- سال چهل و چهارم شماره 1 (پیاپی 85، بهار 1397)
- تاریخ انتشار: 1397/03/20
- تعداد عناوین: 12
- مقاله پژوهشی
صفحات 1-15در این تحقیق، میزان حذف اورتو زایلن با استفاده از گرافن اکسید پیوند داده شده با پلیمر متیل وینیل کتون و آنیلین توسط روش رویه پاسخ مورد بررسی قرار گرفت. آماده سازی جاذب با استفاده از فرایند پلیمریزاسیون توسط آغازگر آمونیوم پر سولفات و پلیمر متیل وینیل کتون انجام شد. سپس، محصول توسط آنیلین اصلاح شد. جاذب نهایی توسط طیف سنج مادون قرمز تبدیل فوریه، میکروسکوپ الکترونی روبشی، طیف سنجی پراش انرژی پرتو ایکس و آزمایش بی ای تی آنالیز شده است. برای کاهش تعداد آزمایشات، از روش رویه پاسخ استفاده شد و تاثیر پارامترهای منتخب (زمان تماس، pH و میزان جاذب) بر روی جذب اورتو زایلن از آب مورد آزمایش قرار گرفت. بعلاوه، شرایط بهینه برای رسیدن به درصد حذف 75 % بدست آمد ( زمان تماس برابر با 11 دقیقه، pH برابر با 4/35 و میزان جاذب برابر با 2/43 گرم بر لیتر). نتایج حاصله نشان داد که درصد حذف اورتو زایلن با غلظت اولیه 20 میلی گرم بر لیتر تحت شرایط بهینه، برابر با 74/5% بوده است. در این مقاله میزان ضریب همبستگی برای جذب اورتو زایلن 99/27% بدست آمد که نشان می دهد مدل دارای اعتبار می باشد.کلیدواژگان: جذب، گرافن اکسید، پلیمریزاسیون، اورتو زایلن، روش رویه پاسخ
صفحات 17-32فلزات سنگین در زمین های کشاورزی جذب گیاهان می شوند؛ وارد چرخه غذایی انسان شده و مقدار بیش از حد آنها باعث بیماری هایی در انسان می شود. بنابراین آگاهی از توزیع مکانی این عناصر برای مدیریت محیط زیست ضروری است. در این تحقیق به بررسی توزیع مکانی فلزات سنگین در شهرستان هریس پرداخته شد. بدین منظور نمونه هایی از خاک تهیه و به اندازه گیری غلظت عناصر (پتاسیم، منگنز، روی، آهن و مس) پرداخته شد. در ادامه با استفاده از روش های ریاضی و روش های زمینآمار به تهیه ی نقشه های خطرپذیری پرداخته شد. در بین روش های مختلف مدل های بهینه با مقایسه ی مقادیر کمترین مربعات خطاها، میانگین مطلق خطاها و میانگین قدرمطلق خطاها مورد ارزیابی قرار گرفتند بدین ترتیب که نزدیکتر بودن معیارهای ذکر شده به صفر ملاک تعیین مدل بهینه قرار گرفت. از بین مدل های بررسی شده برای عنصر پتاسیم، وزن دهی معکوس فاصله، برای منگنز کریجینگ معمولی، برای روی، کریجینگ ساده، برای آهن، توابع پایه ای شعاعی و برای مس نیز توابع پایه ای شعاعی به عنوان روش های انتخاب شدند. سپس به تهیه ی نقشه های پهنه بندی به تفکیک مناطق مختلف با استفاده از شاخص های استاندارد WHO، کلی و استاندارد موسسه ی خاک و آب ایران پرداخته شد و نتایج نشان می دادند که عناصر پتاسیم و مس در محدوده ی غیرمجاز بودند.کلیدواژگان: آلودگی خاک، فلزات سنگین، مدل های درونیابی، کریجینگ، سیستم اطلاعات مکانی
ارزیابی ریسک کمی غیر سرطانزایی برخی از عناصر سنگین در 8 گونه از ماهیان تالاب های بین المللی ایران به روش EPA/WHOصفحات 33-47دف از این مطالعه بررسی میزان جیوه عضله، امعاء و احشاء، گناد و کلیه ماهیان کولمه، تیز کولی، زالون، و میزان جیوه و سرب عضله آمور، کپور معمولی، فیتوفاگ، سرگنده، شیزوسیپریس و هامون ماهی می باشد. این پایش چند گونه ای در راستای ارزیابی ریسک سلامت مصرف کنندگان به روش EPA/WHO صورت گرفته است. طبق نتایج حاصله، غلطت های جیوه در ماهیان مورد مطالعه کمتر از حد پیشنهادی WHO، FAO، FDA، EPA، و EU هستند. غلظت های سرب گونه های آمور، کپور معمولی، فیتوفاگ زیر محدوده پیشنهادی FDA، WHO، FAO، TAL، UK MAFF و NHMRC هستند، اما غلظت سرب شیزوسیپریس و سفیدک بالاتر از حد WHO و TAL قرار دارند. نتایج مطالعه حاضر کمک کرد تا داده هایی از دریای خزر، تالاب انزلی، و تالاب هامون به عنوان شاخص اثرات طبیعی و انسانی روی اکوسیستم های آبی تهیه شود و همچنین نمایه خطرات انسانی مرتبط با مصرف ماهی ارزیابی شود. ریسک سلامت ناشی از دریافت آلاینده های فلزی از عضله ماهیان با استفاده از خارج قسمت خطر (HQ) ارزشیابی گردید. شاخص خطر سلامت انسان نشان داد که ریسک تجمعی با افزایش نرخ مصرف افزایش می یابد، که این موجب نگرانی برای سلامت مصرف کننده شده و لازم است به آن توجه شود.کلیدواژگان: ارزیابی ریسک، فلزات سنگین، تالاب انزلی، دریای خزر، تالاب هامون
بررسی تاثیر صنعتی شدن بر کیفیت محیط زیست در ایران با تاکید بر نقش تعدیل کننده سرمایه اجتماعی(رهیافت فیلتر کالمن)صفحات 49-68آثار و تبعات زیست محیطی، از مهم ترین دغدغه های معطوف به صنعتی شدن به شمار رفته و ازاین رو جستجوی راهکارهای لازم برای کنترل چنین تبعاتی دارای اهمیت زیادی است. مبتنی بر تجارب جدید موجود در زمینه مدیریت مسائل زیست محیطی، سرمایه اجتماعی می تواند با تقویت همسویی و هم افزایی سیاست ها و اقدامات زیست محیطی ، نقش قابل ملاحظه ای را در کنترل ابعاد زیست محیطی معطوف به صنعتی شدن ایفا نماید. در این مقاله سعی شده است نقش سرمایه اجتماعی در کنترل تبعات زیست محیطی حاصل از فرآیند صنعتی شدن در ایران با استفاده از داده های دوره زمانی 1359 تا 1394 مورد بررسی قرار گیرد. بدین منظور با استفاده از رهیافت کالمن فیلتر روند تغییرات اثرگذاری صنعتی شدن بر محیط زیست در ایران برآورد شده است. همچنین با استفاده از روش همگرایی یوهانسون، تاثیر سرمایه اجتماعی بر شدت اثرگذاری صنعتی شدن بر محیط زیست مورد آزمون و تحلیل قرار گرفته است. یافته ها حاکی از آن است که در بلندمدت، ارتباط منفی معنی دار بین سرمایه اجتماعی و میزان تاثیر صنعتی شدن بر محیط زیست در ایران برقرار است. لذا استنباط می شود که روند فرسایشی و در حال کاهش سرمایه اجتماعی در ایران، اثرات منفی صنعتی شدن را بر محیط زیست تشدید نموده استکلیدواژگان: سرمایه اجتماعی، صنعتی شدن، محیط زیست، کالمن فیلتر
صفحات 69-84این مطالعه به تعیین ارزش حفاظتی حوزه آبخیز ابر شاهرود و تعیین عوامل موثر بر میزان تمایل به پرداخت افراد است. در این تحقیق به منظور تعیین عوامل موثر از روش ارزشگذاری مشروط استفاده شده است. برای اندازه گیری میزان تمایل به پرداخت افراد از مدل رگرسیونی لوجیت استفاده شد و براساس روش حداکثر راستنمایی، پارامترهای این مدل برآورد شدند. برای این منظور، تعداد 381 پرسشنامه به روش نمونه گیری تصادفی در استان سمنان تکمیل شد. نتایج نشان داد که متغیرهای سن و درآمد فرد در سطح یک درصد و متغیرهای توانایی مالی، جنسیت، تاهل، هزینه ماهانه، تعداد بازدید و پیشنهاد در سطح احتمال 5 درصد معنی دار و میزان بر تمایل به پرداخت افراد تاثیر داشته است. همچنین نتایج این پژوهش بیان کرد که متوسط تمایل به پرداخت افراد برای حفاظت منطقه 10574 ریال و ارزش حفاظتی برای هر خانوار 126889 ریال در هر سال است. همچنین ارزش حفاظتی سالانه منطقه مورد مطالعه حدود 6/27353 میلیون ریال برآورد گردید. براساس نتایج این تحقیق و ارزش حفاظتی بالای این منطقه پیشنهاد می شود سیاستگزاران و برنامه ریزان با اتخاذ تدابیر لازم و تدوین و تصویب بودجه مناسب کیفیت ارزش ها و ارائه خدمات را ارتقا دهند.کلیدواژگان: تمایل به پرداخت، روش ارزشگذاری مشروط، استان سمنان، ارزش حفاظتی
صفحات 85-98زنجیره تامین پایدار بر مدیریت زیست محیطی تولید، توزیع و مصرف کالاها تاکید دارد. استفاده از ادوات کشاورزی در قسمت تولید گندم منجر به مصرف انرژی و انتشار آلودگی خواهد شد. همچنین دوری مناطق تولید و مصرف، جا به جایی گندم را ناگزیر کرده است. بنابراین، بخش توزیع نیز یکی از قسمت های مهم در مصرف انرژی و انتشار دی اکسیدکربن به شمار می رود.
از این رو، هدف این مطالعه برآورد ارزش سایه ای انتشار دی اکسیدکربن در این دو بخش از زنجیره تامین گندم می باشد. برای این منظور از اطلاعات سال های 1379 تا 1393 استان های ایران و با استفاده از رهیافت تابع مسافت نهاده، مقدار قیمت سایه ای دی اکسیدکربن به تفکیک بخش تولید و توزیع گندم تخمین زده شده است. نتایج تخمین نشان می دهد که هزینه انتشار آلودگی، 7/16 درصد از هزینه تولید گندم را تشکیل داده و اعمال آن باعث کاهش نسبت درآمد به هزینه گندم از 55/1 به 33/1 می شود. از طرف دیگر ارزش سایه ای انتشار دی-اکسید کربن در بخش توزیع بیشتر از بخش تولید بوده است. بر همین مبنا بایستی اقدامات لازم برای تولید و توزیع پایدار در مورد محصول استراتژیک گندم اعمال گردد، به طوریکه کمترین خسارت به محیط زیست وارد شود.کلیدواژگان: گندم، ارزش سایه ای آلودگی، مسافت نهاده، زنجیره تولید و توزیع
صفحات 99-111تغییر کابری اراضی از دو دیدگاه خرد و کلان قابل بررسی است. از نظر کلان سیاست های دولت و عوامل اقلیمی و از نقطه نظر خرد ویژگی های فردی و اقتصادی کشاورزان بر تغییر کاربری اراضی موثر هستند . استان خراسان رضوی یکی از مناطقی است که تغییر کاربری اراضی کشاورزی در آن در سال های گذشته با شدت بیشتری صورت گرفته است. در این مطالعه عوامل موثر بر تغییر کاربری با استفاده از اطلاعات میدانی 70 کشاورز در شهرستان تربت حیدریه به روش نمونه گیری تصادفی طبقه بندی شده در سال 1396 بررسی شد. تحلیل مولفه های اثر گذار با استفاده از الگوی هکمن - توبیت دو مرحله ای انجام شد. نتایج حاصل از برآورد الگوی هکمن دو مرحله ای نشان داد که در مرحله ی نخست متغیرهای جمعیت خانواده ی کشاورز، تعداد قطعات اراضی، درآمد کشاورز، قیمت محصول عمده ی تولیدی، سطح سواد کشاورز، سطح بارندگی و میزان دسترسی به چاه های آب بر تمایل به تصمیم جهت تغییر کاربری اراضی تاثیر گذار می باشند. نتایج مرحله ی دوم الگوی هکمن نشان داد که که جمعیت خانواده کشاورز، درآمد کشاورز، قیمت محصول عمده ی تولیدی و سطح بارندگی و میزان دسترسی به چاه های آب، عوامل موثر بر میزان تغییر کاربری اراضی کشاورزی می باشند.کلیدواژگان: زمین، تغییر کاربری، تربت حیدریه، الگوی هکمن توبیت
صفحات 113-129آلودگی هوا یکی از انواع آلودگی های زیست محیطی است که بقا و سلامتی موجودات زنده از جمله انسان را تهدید می کند. بعد از انقلاب صنعتی و به خصوص در یک صد سال اخیر به علت پیشرفت تکنولوژی صنعتی و تولید انواع وسایل نقلیه، میزان آلودگی هوا در جهان افزایش پیدا کرده است. درختان با فیلتر کردن و جذب آلاینده ها، نقش مهمی در کاهش آلودگی هوا ایفا می کنند و یکی از ابزارهای طبیعی در مهار آلودگی هوا هستند. هدف این تحقیق برآورد منافع اقتصادی حاصل از حفظ و کاشت برترین گونه ی درختی کاهش دهنده آلودگی هوای سطح شهر اهواز در سال 94 است. بدین منظور گونه های درختی که بیشترین فراوانی را در سطح شهر اهواز دارند، انتخاب شدند. سپس با استفاده از روش های آزمایشگاهی و شاخص های سنجش توان گونه ی درختی برای جذب آلاینده های هوا و صوت، برترین گونه درختی تعیین شد (درخت برهان). در نهایت با استفاده از نمونه گیری طبقه ای و روش مدل سازی انتخاب منافع اقتصادی حاصل از خدمات تصفیه ای این گونه درختی محاسبه گردید. نتایج نشان داد که تمایل به پرداخت ساکنان شهر اهواز با حفظ و کاشت بیشتر این گونه ی درختی افزایش می یابد. همچنین ارزش سالانه منافع و ارزش سرمایه ای درخت برهان به ترتیب 1167 و 1852 میلیارد ریال محاسبه شد.کلیدواژگان: آلودگی هوا، مدل سازی انتخاب، تمایل به پرداخت، ارزش سرمایه ای گونه درختی، شاخص های APTI
بررسی و مقایسه ارزش اقتصادی کارکرد ترسیب کربن پوشش گیاهی در عملیات بیولوژیک (مطالعه موردی: مراتع استپی سربیشه - استان خراسان جنوبی)صفحات 131-148یکی از مهمترین کارکردهای اکولوژیکی مراتع بویژه مراتع تخریب یافته پتانسیل بالای ترسیب کربن به عنوان مهم ترین گاز گلخانه ای می باشد. احیاء مراتع تخریب شده مناطق خشک ایران اهمیت ویژه ای در حفظ تعادل چرخه کربن دارد. در نظر گرفتن ارزش اقتصادی کارکرد ترسیب کربن از طریق محاسبات مالی می تواند نقش موثری در برنامه ریزی های زیست محیطی داشته باشد. لذا تحقیق حاضر با هدف بررسی تاثیر اجرای عملیات احیای پوشش گیاهان مرتعی بر ارزش اقتصادی ترسیب کربن گیاهان انجام گرفت. به این منظور سه نوع فعالیت احیایی بوته کاری، هلالی آبگیر و بذرکاری- بذرپاشی انتخاب و مناطق شاهد مشخص شد. جهت ارزشگذاری میزان کربن ترسیب یافته از روش سیاست مالیات بر کربن استفاده شد. بر اساس نتایج تحقیق میزان جذب کربن در مراتع منطقه مورد مطالعه 774 تن برآورد گردید. ارزش سایه ای جذب کربن سالانه، 8/54721 دلار/تن (معادل 191526399ریال/تن) بدست آمد. ارزش هر هکتار از این مراتع برای کارکرد ترسیب کربن برابر با 35/17 دلار (معادل 15/60744 ریال) برآورد گردید. بنابر نتایج بدست آمده، عوامل مدیریتی همچون عملیات احیایی، نقش مهمی در کنترل ترسیب کربن داشته است. همچنین ترسیب کربن فعالیت احیایی بوته کاری، بطور معنی داری موفقیت بیشتری در ارتقای شاخص های اکولوژیکی و ارزش ریالی ترسیب کربن در مقایسه با مناطق شاهد داشته است.کلیدواژگان: ترسیب کربن، عملیات احیایی، پوشش گیاهی، ارزش اقتصادی، مراتع استپی
بررسی، ارزیابی و تدوین تاب آوری کاربری اراضی شهری بر پایه رویکرد توسعه پایدار (نمونه موردی: منطقه ی 1 تهران)صفحات 149-169کلان شهرها، محل تراکم بالای جمعیت و پدیده های انسان ساخت هستند. در صورت وقوع سیل و زلزله در کلان شهرها و نبود آمادگی برای مقابله با این بلایای طبیعی، احتمال بروز خسارات جانی و مالی بالا می رود. به منظور جلوگیری ازاین امر، استفاده از رویکردتاب آوری کاربری اراضی شهری از اهمیت و ضرورت دو چندانی برخوردار می گردد. هدف کلی از پژوهش حاضر، بدست آوردن عوامل تاثیرگذار در میزان تا ب آوری کاربری اراضی شهری با رویکرد توسعه پایدار و تعیین میزان اهمیت نقش هر یک ازمعیارهای تاب آوری و بررسی آن ها درمنطقه ی 1شهر تهران، که دارای جمعیت زیاد وموقعیت ویژه ی زمین شناسی است، می باشد.روش تحقیق این پژوهش، توصیفی تحلیلی، و ماهیت آن کاربردی است. در این پژوهش، ابتدا مبانی نظری تحقیق از طریق جمع آوری اطلاعات و مطالعات اسنادی صورت پذیرفت. در ادامه به منظور بررسی میزان تاب آوری کاربری اراضی، معیارهای تا ب آوری براساس نظرات کارشناسان و بررسی پژوهش های قبلی صورت گرفته، تعیین گردید. سپس به کمک 15 نفر از اعضای متخصص که در حوزه ی برنامه ریزی محیط زیست، برنامه ریزی شهری، برنامه ریزی روستایی و شهرسازی تخصص داشته اند، مقایسات زوجی شاخص ها صورت پذیرفته است. همچنین به منظور ارزیابی و بررسی نهایی میزان تاب آوری، از روش FAHP، سیستم اطلاعات جغرافیایی(GIS) و Idrisi، TOPSIS و SWOTبهره گرفته شده استکلیدواژگان: کلان شهرها، تاب آوری، کاربری اراضی شهری، توسعه پایدار
صفحات 171-188براساس نوشته های مورخان همواره برای توصیف تهران از باغ بهره برده شده است، عنصری که منشا حضور تهران و در اسناد تاریخی دارای جایگاه خاصی می باشد؛ پرسش اصلی این نوشتار این است که آیا می توان بیان نمود که باغ عامل اصلی ایجاد شهر و توسعه تهران بوده آیا می توان بیان کرد موجودیت شهر تهران از باغ نشات گرفته است؟ مقاله حاضر با روش تاریخی- تحلیلی و اکتشافی از متون تاریخی و اسناد و مدارک از دوران شروع مدنیت شهر تهران به جمع آوری مطالب براساس تحلیل تاریخی و توصیفی به برداشت لایه های زمانی می پردازد. سپس با تجزیه و تحلیل لایه های تاریخی باغ در بستر شهر تهران همزمان به شناخت رابطه دوطرفه بین بستر طبیعی و تاثیر متقابل فرهنگ و شهر و معماری می پردازد. فرض این مقاله بر این است که رابطه مستقیمی بین باغ و بوجود آمدن یک شهر از یک طرف و از طرف دیگر بین رشد شهر تهران و بستر طبیعی و باغ به ویژه باغ گلستان تهران وجود دارد. سعی این مقاله بر این است که تاثیر متقابلی که بین بستر طبیعی و باغ و شهر و معماری ارتباط دوطرفه ای وجود دارد را کشف و ارائه نماید.کلیدواژگان: باغ گلستان، توسعه شهری، ارگ سلطنتی، شهر تهران، بستر طبیعی
صفحات 189-203گسترش کلان شهرها در دهه های اخیر پیامدهای متعدد کالبدی، اجتماعی- اقتصادی و محیط زیستی در پی داشته است. یکی از این پیامدها تشدید پدیده جزایر حرارتی شهری در نواحی با آب و هوای معتدل تر بوده است. اما در نواحی کلان شهری با آب و هوایی گرم و خشک تر افزایش شهرنشینی نه تنها موجب تشدید جزایر حرارتی نمی شود بلکه در فصول گرم سال دمای سطح زمین را کاهش نیز خواهد داد. کاهش دمایی که از آن با عنوان پدیده جزایر سطحی سرد شهری یاد می شود. پژوهش های پیشین از طریق استخراج نقشه های کاربری/پوشش زمین از تصاویر ماهواره ای و مقایسه نسبت هر کاربری زمین با دمای سطحی تاثیر این پدیده در روزهای مختلف سال را در یک شهر نشان داده اند. اما با این وجود تاثیر پیچیدگی شکل نواحی ساخته شده و همچنین ویژگی های کالبدی ساختمان ها همچون تراکم ساختمانی و ریزدانگی بر تشدید پدیده جزایر سرد شهری مغفول مانده است. این پژوهش با مطالعه تاثیر ترکیب بندی و پیکربندی نواحی ساخته شده و ویژگی کالبدی آن ها بر دمای سطحی شهر شیراز با استفاده از سنجه های سرزمین به این نتیجه دست یافت که هرچه پیچیدگی شکل نواحی ساخته شده کمتر باشد و همچنین تراکم ساختمانی و ریزدانگی نواحی شهری افزایش یابد پدیده جزایر سرد شهری تشدید می شود.کلیدواژگان: جزایر سطحی سرد شهری، دمای سطح زمین، سنجه های سیمای سرزمین، تراکم ساختمانی، ریزدانگی
Application of polymerized graphene oxide for optimization of o-xylene removal from aqueous solutions through response surface methodologyPages 1-15IntroductionFollowing an accidental oil spill, the removal of surface oil are usually the important concern for decreasing energy loss and damage to the environment. O-xylene is one of the common compounds which exist in the effluent of oil and petroleum industries. Consequently, the removal of o-xylene from groundwater and surface waters is essential. The one of main techniques that are useful for cleaning up the soluble oil are adsorption. Adsorption methods are simple and economical and the removal of toxic chemicals using porous adsorbents has aroused attention. Graphene as a new synthetic 2D allotrope of carbon has advantages as an adsorbent due to its flexible structure. Graphene has a very fine potential as adsorbent material due to its low cost and environmentally friendly product and by the fact that graphene can be reused without any significant change in its adsorption capacity.Materials And MethodsPreparation of graphene oxide (GO)
GO was prepared from graphite powder by Hummers and Offeman method.
Polymerization of GO
2 g of GO powder were dissolved in 20 ml of dimethylformamide with stirring. Then, allylamine (10 ml) was added to the solution by continuous stirring at 160 rpm for 2 days. Later, the mixture was washed via dimethylformamide and filtered, the product was dried at room temperature.
The grafting of GO with allylamine (GO-AA) was transferred into the flask and was dissolved in 30 ml of methanol. Next, APS (0.75 g) and MVK (30 ml) were rapidly poured to the solution. The mixture was heated at 60°C in a nitrogen atmosphere for 5 h under stirring. The solution was washed with methanol and filtered. At the end, the product was dried at room temperature.
Modification of polymerized GO with methyl vinyl ketone (GO-MVK)
At first, GO-MVK was mixed with ethanol (150 ml) and aniline (50 ml) and added into the flask. The mixture was fitted under atmosphere of nitrogen at 40°C for 6 h, with agitation speed of 180 rpm. After filtering, the final product was washed with ethanol and further dried in vacuum oven at 40°C for 3 days.
Batch adsorption experiments
For batch adsorption experiment, the desired dosage of graphene oxide grafted with poly methyl vinyl ketone and aniline (GO-MVK-ANI) was mixed with 50 ml of aqueous o-xylene solution (20 mg/l) in a 100 ml flask which was shaken using a rotary shaker at 150 rpm at 25 ± 2ºC. Then, the solution was filtered with syringe filter. The concentration of o-xylene was quantified using GC-FID.
RSM is the statistical and mathematical method for designing experiments, building models, and estimating the effects of several factors for desirable responses. This technique is suitable for optimizing the effective parameters with a minimum number of experiments. Herein, the effects of 3 variables in adsorption process including contact time, initial pH and adsorbent dose were investigated with a standard central composite design (CCD). The number of experiments is selected 20 basing on a 23 full factorial CCD for the 3 factors. Five levels of factors were investigated according to the obtained experimental data using MINITAB 16 which are presented in Table 1.
Table 1 Experimental range and levels of independent variables
Variable Factor Unit Range and level
-α -1 0 1 α
Contact time X1 min 10.91 45 95 145 179.09
Initial pH X2 - 4.31 5 6 7 7.68
Adsorbent dose X3 g/L 0.05 0.8 1.9 3 3.75
Finally, the optimum value of parameters has been earned for the selected target (o-xylene removal efficiency) in optimization process of RSM program.Results And DiscussionThe synthesized product was characterized via Fourier transform-infrared resonance (FTIR) spectroscopy, scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX) spectroscopy and Brunauer-Emmett-Teller (BET) analysis. The total pore volume and average pore diameter of the GO are enlarged by polymerization and modification. The effect of three different parameters including the contact time, initial pH and adsorbent dose on adsorption process of o-xylene using GO-MVK-ANI were investigated. The o-xylene adsorption behavior at different contact time was carried out and shown in Fig. 1a. As can be seen, the maximum o-xylene removal was observed in the initial 10 min of adsorption process. Then, the adsorption capacity became constant, approximately. The effects of pH on adsorption capacity are shown in Fig. 1b. There was no significant change in removal efficiency during the increasing of the pH range. According to Fig. 1c, when adsorbent dose increased, the o-xylene removal efficiency improved. The reasons of this enhancement are that the surface area of the adsorbent, available adsorption sites and also active functional groups are improved with increasing of adsorbent dose. Basing on RSM results, the R2-value is found very high for o-xylene removal (R2 = 99.27%) which is a good confirmation between the experimental and the predicted results. Finally, the optimization of adsorption process was applied for the removal of o-xylene. The experimental checking under optimum conditions (the contact time of 11 min, pH of 4.35 and adsorbent dose of 2.43 g/L) was obtained 74.5% for o-xylene removal efficiency which is close to the model result (75 %).
Fig. 1 Main effects of (a) contact time, (b) initial pH and (c) adsorbent dose on o-xylene removal efficiency using GO-MVK-ANIConclusionsThe aim of this research was to investigate GO-MVK-ANI to adsorb o-xylene from aqueous solutions. The total pore volume and average pore diameter of GO were improved from (0.016 cm3/g, 4.853 nm) to (0.022 cm3/g, 23.187 nm) by polymerization and modification. Based on the results acquired, adsorption contact time was 11 min. It confirms that this adsorbent has high efficiency in the removal of o-xylene for conditions that need rapid treatment. Moreover, GO-MVK-ANI has high stability in the different ranges of solutions pH. According to the ANOVA results, the model presents high R2-value of 99.27% for o-xylene removal and indicates that the accuracy of the polynomial model was successful. The o-xylene removal efficiency under experimental optimum conditions was obtained 74.5% which confirms close to the RSM results.Keywords: Adsorption, Graphene oxide, Polymerization, O-xylene, Response surface methodology
Pages 17-32It is inevitable to analyze the existing contaminant elements in soil as the most important source of nutrition for human. Heavy metals are considered and referred among these elements. The contaminated soils of urbanized regions are directly related to human, while these elements are absorbed by plants in agricultural fields, through which they enter the human food cycle. The excessive increase of these elements in soil results in the growing incidence of certain diseases such as cancer. Moreover, the irresolvability of these materials may have dangerous impacts on the human digestion as well as nervous systems. Contamination, due to heavy metals in soil, have even resulted in some animals death.
There are various factors involved in soil contamination. One of main factors is the incorrect use and increasingly irregular exploitation of nature by human beings. In Iran, inappropriate economic exploitation of agricultural fields and aberrant use of chemicals have led to the higher concentration of heavy metals in soil, turning to a crucial problem in certain areas. The most significant cause of soil contamination is the wrong use of chemical fertilizers, resulting in the agglomeration of heavy metals in soil. Therefore, it is inevitable to identify the spatial distribution of these elements. The geo-statistical instruments have facilitated the quantification of soil spatial characteristics, whereby leading to the probability of spatial interpolation.
Objective of the study are: (i)To prepare zoning maps of elements including Zinc, Copper, Iron, Manganese, Potassium, and Lead using mathematics and geo-statistics methods as well as choosing the most optimum technique of spatial interpolation by comparing RMSE, MAE and MBE;(ii)To analyze the probable spatial correlation between the concentration of these elements in agricultural soils;(iii)To distinguish the regions affected by the excessive contamination higher than the threshold limit of general index and WHO standard and also Irans Soil and Water Research Institutes standard.Materials And MethodsHarris Town is located in the north-western Iran between 38°04° and 38°24° latitudes of northern hemisphere and of 46°22° and 47°22° geographical longitudes of eastern hemisphere.
In this research, first of all, 370 samples of soil were randomly selected from this region and the concentrations of abovementioned elements were measured in the laboratory. Then, the accuracy of the measured data was examined by applying 3Sigma Validation Test. At the next stage, the spatial distribution of the elements of Zinc, Iron, copper, Manganese, and Potassium was examined using Mathematics and geo-statistics interpolation models. These methods which are based on the first principle of geography include certain mathematical methods such as the Inverse Distance Weighting, Local Polynomial, and Radial Basis Functions and geo-statistics methods such as Ordinary Kriging (OK), Simple Kriging (SK), and Universal Kriging (UK) with Circular, Globular, Gaussian, and Exponential Variogram Models.
Kriging is one of the geo-statistical interpolation methods, which is based on Weighted Moving Average. One of the features distinguishing it from other interpolation methods is that it is regarded as the Best Linear Unbiased Estimator. The first stage in statistical analyses is the computation and drawing of variogram. In fact, variogram represents the variability of samples based on their distance. The next stage is the selection of the best theoretical model for fitting to experimental variogram. The modeled variogram shows the spatial self-correlation of data, and describes range, sill and nugget. The Kriging interpolator is divided into different methods. The models being tested in this research are Ordinary, Universal and Simple Kriging.
Inverse Distance Weighting
The Inverse Distance Weighting is a radix point method which acts based on the first principle of geography. In this interpolation method, the weighting parameter operates according to the criterion that an increase in the distance from the sampled points to the passive point leads a decrease in its effect in the expected (predicted) value.
Local PolynomialMethodPolynomial interpolation is a method for finding a formula, the figure of which passes through the data. The Universal Polynomials identify the fitted surface to data by considering all existing data in the analysis, while local polynomials performs this action for a limited number of points within a considered oval. This method allocates the least proportional squares among the identified points in the oval shape area as the point weight. Thus, interpolation is performed based on the allocated weight of the relations of the first, second and/or third grades among the variables in the neighboring points of X, Y, and Z along with the minimization of estimated errors.
Radial Basis Functions
This method is a manner of artificial neural networks in which the predicted values are higher than the maximum observed and lower than the existing minimum observed. Indeed, the surface fitting by these functions acts like a plastic membrane so as to minimize the total surface curvature. The Radial Basis Functions performs interpolation based on five principal functions. The main core of these functions is the sum of squares values. In this method, a function is considered for each location (place), where the linear combination of these functions is used for predicting the amount of function in the passive location as the final function. In this study, five functions including Spline Function, Quite Regular, Spline with tension, Multi-Quadric function, Reverse Multi-Quadric Function and Spline Function with the thin surface were used.
Validation Criterion of InterpolationMethodsIn this research, the observed data were divided in two groups of experimental and control, with the proportion of 80 to 20. At the beginning, by applying the experimental data, a surface was fitted for the data using each interpolation method. Jackknife Cross-Validation Method was used to determine errors vector. The basis of this method is that when fitting the surface, one of the data is omitted each time, fitting is performed by using other data and the data deviation from the predicted value is recorded. Then, the control data is inserted in the fitted model and the amount of data deviation from the fitted model is being reported.
In order to examine the accuracy and validation of each method in the zoning of the aforementioned heavy metals, Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Mean Basin Error (MBE) were applied. The closer the values of (RMSE), (MAE), and (MBE) to zero, the more efficient (effective) the performance of the fitted model.Results And DiscussionAll obtained numbers for the spatial correlation between the elements are of positive value, and this represents a direct relation in the reciprocal transformations of elements. Among the results obtained, the spatial correlation between two metals of Zinc and Copper is more intense, as with 46%, include the most intense relation as compared to each pair of other elements. Meanwhile, the correlation between the two elements of Manganese and Potassium has the least value with 1%.
By using the QQ chart, it was found the data of Potassium, Zinc, Iron and Manganese have a relatively high skewedness and far from normal distribution.
As it was previously indicated, variogram explains the relation between sample variability as well as their interaction. In order to choose the best model of experimental variogram, the proportion of nugget to sill was used, in which the least value represents the best model (Figure 3).
By using Arc GIS Software, the most optimum model for the preparation of zoning maps was examined. Among the various models, deviation vectors were drawn from the measured value for the fitted surface. These vectors were drawn for both sets of data. By comparing the measured data and the global index of soil contamination and WHO standard, it was found that the highest volume of elements of Iron, Copper, and Manganese are not located in the permissible range, while the amount if this element is located in the impermissible range in the whole region under study. (Figures 4 to 8).Keywords: Soil Pollution, heavy metals, interpolation models, Kriging, GIS
Non-carcinogenic quantitative risk assessment of heavy metals in 8 fish species of Iranian international wetlands by EPA/WHO instructionsPages 33-47IntroductionIn between aquatic ecosystems, wetlands and rivers have a great ecological importance. Heavy metals from geological and anthropogenic sources are increasingly being released into natural waters. Contamination of aquatic ecosystems with heavy metals has seriously increased worldwide attention, and a lot of studies have been published on the heavy metals in the aquatic environment. Under certain environmental conditions, heavy metals may accumulate to toxic concentrations and cause ecological damage. Mercury is a special concern in marine ecosystems, where methylation occurs during the process of biotransformation and accumulates in biota. Mercury is a toxin to the central nervous system and it can readily cross the placental barrier. Lead is attracting wide attention of environmentalists as one of the most toxic heavy metals. The sources of lead release into the environment by waste streams are battery manufacturing, acid metal plating and finishing, ammunition, tetraethyl lead manufacturing, ceramic and glass industries printing, painting, dying, and other industries. Lead has been well recognized for its negative effect on the environment where it accumulates readily in living systems. Lead poisoning in human causes severe damage to the kidney, nervous system, reproductive system, liver and brain.
The aim of this study is determination of mercury concentration in the muscle, intestine, gonad and kidney of Rutilus rutilus, Hemiculter Leucisculus (Anzali wetland), and Alosa Caspia Caspia (Caspian Sea), and mercury and lead concentrations in the muscle of Ctenopharyngodon idella, Cyprinus carpio, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis, Schizocypris altidorsalis, and Schizothorax zardunyi (Hamun wetland). The results of this study were compared with global standards. As well as in this multispecies monitoring, health risk assessment of consumers by EPA/WHO instructions has been done. The main objective was to evaluate the potential health risks associated with heavy metals via consumption of fish from the wetlands using the Average Daily Dose for Intake Process (〖ADD〗_pot) and Hazard Quotient (HQ) from heavy metals.Materials And Methods2-1- Case study
The Caspian Sea (Fig. 1), which is located in the northern I.R. Iran, is the largest lake in the world and is connected to the distant Baltic through canals and the River Volga. It is unique closed water basin, plays the important role in the establishment of the climate. The Anzali Wetland (193 km2) (Fig. 1), located on the southern coast of the Caspian Sea, is internationally known as an important wetland for migratory birds, and was registered as a Ramsar site in June 1975 in accordance with the Ramsar Convention. Hamun wetland, the largest freshwater expanse of the Iranian plateau, is listed in the Convention on Wetlands, Ramsar.
The fish species including Rutilus rutilus, Hemiculter Leucisculus (from Anzali wetland), and Alosa Caspia Caspia (from Caspian Sea), Ctenopharyngodon idella, Cyprinus carpio, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis, Schizocypris altidorsalis, and Schizothorax zardunyi (Hamun wetland) randomly were collected.
Fish samples (20 samples from each species) were transferred to the laboratory and stored in refrigerator. Afterwards, the tissues were separated and dried.
2-3- Mercury and lead analysis
The dried samples were ground and changed into a homogenous powder and then the mercury concentration rate has been determined by advanced mercury analyzer, model 254. Lead concentration rate has been determined by Atomic Absorption Spectroscopy (AAS), Perkin Elmer 4100.
2-4- Health risk assessment by EPA/WHOMethod2-4-1- Hazard Identification
Hazard identification involves gathering and evaluating toxicity data on the types of health injury or disease that may be produced by a chemical and the conditions of exposure under which injury or disease is produced. The subset of chemicals selected for the study is termed chemicals of potential concern. Data from acute, subchronic, and chronic dose-response studies are used.
2-4-2- Dose-Response Assessment
The dose-response assessment involves describing the quantitative relationship between the amount of exposure to a chemical and the extent of toxic injury or disease. The US EPA established the Reference Dose (RfD) as below:RfD = (NOAEL or LOAEL)/(UF ×MF)
NOAEL: No Observed Adverse Effect Level
LOAEL: Low Observed Adverse Effect Level
UF: Uncertainly Factor
MF: Modifying Factor
2-4-3- Exposure Assessment
Applies a generalized dose-response relationship to specific conditions for some population. Characterizes the sources of an environmental hazard, concentration levels at that point, pathways, and any sensitivities. Exposure assessment involves describing the nature and size of various populations exposed to a chemical agent, and the magnitude and duration of their exposures. The exposure pathway of heavy metals to human through ingestion of contaminated food has been studied by many researchers. Average Daily Dose for Intake Process 〖ADD〗_pot is calculated as:〖ADD〗_pot=( (C× IR×ED))/(BW×AT)
C: Concentration of toxic material
IR: Ingestion Rate
ED: Exposure Duration
BW: Body Weight
AT: Averaging Time
2-4-4- Risk Characterization/Risk calculation
The Average Daily Dose for Intake Process (〖ADD〗_pot) (Total Intake) is compared to the RfD. If 〖ADD〗_potResults And DiscussionThe concentrations of Hg in tissues of Rutilus rutilus, Hemiculter Leucisculus, and Alosa Caspia Caspia was measured (Table 1).There was no significant difference between the independent variables of gender, age and weight of the dependent variable is the amount of mercury in the tissues of the Rutilus rutilus. But between the length and the amount of mercury in the kidney of Rutilus rutilus, there was significant difference at 95% (p=0.015) (Figs 2 and 3).
Mean concentrations of Hg in muscle of Ctenopharyngodon idella, Cyprinus carpio, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis, Schizocypris altidorsalis, and Schizothorax zardunyi were 0.14, 0.28, 0.15, 0.15, 0.34 and 0.36 mg/kg respectively (Table 1). The results of laboratory analysis showed that there are significant difference between the concentration of mercury in the muscle between species (p0.05).
Table 1 shows ADDpot and HQ of heavy metals in muscles of fish samples from the wetlands. Among the fish species examined in this study, Hemiculter Leucisculus with a HQ value of 0.009 has the lowest potential health risk to mercury and Schizothorax zardunyi with a HQ value of 1.2 has the highest potential health risk to mercury. The HQ through the consumption of Schizocypris altidorsalis and Schizothorax zardunyi was higher than 1 (for mercury), indicating that there is potential health risk associated with the consumption of these fish from the hamun wetland. The results for lead concentration indicate that there is no HQ value > 1, indicating that humans would not experience any significant health risk if they only consume metals from these species of fish from the hamun wetland. The concentrations of mercury in all species were below the limits for fish proposed by United Nations Food and Agriculture Organization (FAO), World Health Organization (WHO), US Food and Drug Administration (FDA) and US Environmental Protection Agency (EPA), and European Union (EU) (Table 2). Lead concentrations in Ctenopharyngodon idella, Cyprinus carpio, Hypophthalmichthys molitrix were under the scope proposed by FAO, WHO, FDA, Turkish Acceptable Limits (TAL), United Kingdom Ministry of Agriculture Fisheries and Food (UK MAFF) and National Health and Medical Research Council (NHMRS), but lead concentration in Schizocypris altidorsalis, and Schizothorax zardunyi were higher than WHO and TAL (Table 2).
It should be noted that maximum consumption of 0.020 kg/day of Schizocypris altidorsalis and 0.019 kg/day of Schizothorax zardunyi there is no potential health risk (CRlim).ConclusionThe results of the present study aimed to provide data from Caspian Sea, Anzali wetland, and Hamun wetland as indicators of natural and anthropogenic impacts on aquatic ecosystem as well as to evaluate the human hazard index associated with fish consumption. The human health hazard Quotient (index) showed that the cumulative risk greatly increases with increasing fish consumption rate, thus yielding an alarming concern for consumer health.Keywords: Risk assessment, Heavy metals, Anzali wetland, Caspian Sea, Hamun wetland
Investigating the effect of Industrialization on Environment quality in Iran emphasizing the Moderating Role of Social Capital (Kalman Filter Approach)Pages 49-68IntroductionOne of the main concerns of industrialization is the corresponding environmental effects. Industrialization has affected the entire environment with its severe downside problems. The formation of massive pollution made by industries are the result of the constant need and greed of the human being. These industries, including transportation and manufacturing, are exhausting the earths resources and are causing tremendous stress on the environment and the ecological system. Water, soil and air pollution, are defined as the negative results of industrial development and industrialization. Global warming and greenhouse effects are the result, which is a massive impact of industrialization on the environment. The degradation of the entire environment and ecological system, is inclined to become permanent and tends to cause several negative effects on the economy, by causing human losses, ill health of the employees at large costs to governments, manufacturing and society. Therefore, it is very important to find necessary solutions to control such effects to facilitate the conditions for achieving sustainable industrial growth. This requires to identify the exact effects of industrialization on environment and the factors and solution which can mitigate this kind of bad effects of industrialization. According to the literature, there are a wide variety of variables that can help policymakers to control the side effects of industrialization. Social capital is one of these factor. Social capital comprises relations of trust, reciprocity, common rules, norms and sanctions, and connectedness in institutions. Social capital is necessary for sustainable and equitable solutions to natural resource management. This paper is to investigate the contribution of social capital in moderating the environmental effects of industrialization.Materials and MethodData for variables included in the estimated econometric models in this paper- including per capita carbon dioxide emission(as environment quality index), per capita income, per capita industrial value added (as industrialization index), energy use intensity, urban population, human capital and social capital - is gathered from Iran central bank data center during the period 1967-2015. Augmented dickey fuller test is used to investigate the stationary of variables included in the econometrics models of the study. In order to analysis the moderating role of social capital as well as human capital in the reaction of environment quality to industrialization in Iran, two steps were taken as follows: at the first step, the effect of industrialization on environment quality was estimated using Kalman filtering approach during the period 1967-2015. At the second step, the moderating role of social capital is tested using Johnson co integration approach. Sohwarz and Quinn criteria were used to determine the optimal lag numbers in vector autoregressive model. The number of co-integration vectors was determined using maximum eigenvalue and trace tests. Vector error correction model is used to test and analyze the partial short-run adjustments.
Discussion ofResultsAugmented dickey fuller test shows that the order of integration of all variables is one and so these variables are not stationary series at level. This results lead the research team to use co integration test to analysis the relationship between variables. Estimation of the environment quality function, by Kalman filter approach estimation, shows that per capita carbon dioxide emission (environment quality index) is positively influenced by first power of per capita income, per capita industrial value added(industrialization index), energy use intensity and urban population. This finding is in line with the theoretical expectation and many other empirical researches in this field. The coefficient of the first power of per capita income in estimated model is 0.1659 and indicates that if the first power of per capita income increase one unit, per capita carbon dioxide emission increase 0.1659 unit. The coefficient of the energy use intensity in estimated model is 0.0005 and indicates that if energy use intensity increase one unit, per capita carbon dioxide emission increase 0.0005 unit. The coefficient of the urban population in estimated model is 0.0027 and indicates that if urban population increase one unit, per capita carbon dioxide emission increase 0.0027 unit. The coefficient of per capita industrial value added(industrialization index) in estimated model is 0.8176 and indicates that if industrialization index increase one unit, per capita carbon dioxide emission increase 0.8176 unit. There is a positive and statistically significant relationship between per capita industrial value added and per capita carbon dioxide emission. Estimation of industrialization coefficient in environment quality function using Kalman filtering reveals that this coefficient has experienced an increasing trend during the period 1982 -2015. This finding shows that the degree of industrialization side effects on environmental quality has been intensified during the period. Co integration test based on eigenvalue and trace statistics in this paper confirm the presence of almost one co integration vectors between the model variables. According to the estimated coefficients of restricted vectors, there is a long term negative relationship between social capital and the coefficient of industrialization in environment quality function. The coefficient of social capital in restricted vector is estimated around -12.1956. This shows that, in long term, as social capital improve or increase around one unit, the coefficient of industrialization in environment quality function decrease and mitigate around 12.19 unit. According to the estimated vector error correction model, social capital and human capital does not significantly affect the degree of industrialization effects on environment quality.ConclusionsBased on the negative and significant coefficient of social capital in environment quality function estimated in this paper, it is inferred that the fraying trend of social capital has intensified the negative environmental side effects of industrialization in Iran during last decades. At the same time, improving the peoples awareness of environmental supportive activities, has mitigated the harmful effects of industrialization. According to the findings, related organizations and institutions like industrial organization, environmental organization, and other cultural institution are strongly recommended to have a close cooperation in order to design and implement the comprehensive and integrated program to manage the environmental side effects of industrialization process in Iran. Top down approaches and policies are not enough to ensure the applicability of measures in field of environmental protection. People participation in environmental activities is the main precondition to enhance the effectiveness and efficiency of environmental side effects management in industrial projects and activities. This requires the proper level and structure of trust, networking and social capital in the society.Keywords: Social Capital, Industrialization, Environment, Kalman Filter
Estimating the preservation value of environmental resources of Abar area of Shahrood by using individual's willingness to payPages 69-84Estimating the preservation economics value of environmental resources by using individuals willingness to payIntroductionValuation of non-market functions and services of the natural resources and the environment is important due to some reasons including understanding the environmental and ecological benefits by humans, feedback of the importance of environmental issues to the planners, creating the relation among economic policies and incomes from natural resources, measuring the role and importance of the environmental resources in improving the welfare of society and sustainable development, adjusting and reforming the national accounts such as gross national product (GNP), and preventing the uncontrolled destruction and exploitation of natural resources. The maximum willingness to pay (MWTP) by the users for non-market goods such as improving the quality of the environment, wildlife, and forests represents the economic value of the resources (Kealy and Turner 1993). In recent years, economists and policy makers have used CVM to estimate this value and the other economic values.
The Contingent Valuation Method (CVM) is applied as a standard and flexible tool to measure the use and non-use values of the environment for which there is no market (Amigues et al. 2002). This method was firstly introduced by Ciriacy and Wantrup in 1947 and also it was for the first time used by Davis in 1963. This method specifies the individuals willingness to pay (WTP) in the form of hypothetical tools (Han and Lee 2002). The evaluator in this method refers to the people in order to determine the economic value of the goods and environmental services of the environment such as wetlands and then measures their preferences based on the offered prices. Thats why CVM is often called as the preferred method, too (Venkatachalam 2003).
The objective of this research is evaluation WTP of the individuals who were categorized into two different groups of consequentialists and deontologists to estimate the conservation value of the Abar watershed of Shahrood that located in the Semnan Province. Also, was determined the factors affecting on the WTP to estimate the conservation value of the study area.
Matherials &MethodsContingent Valuation Method (CVM) was used in this research to determine the conservation value. The WTP is determined under the certain hypothetical market scenarios. Dichotomous Choice (DC) methods are more consistent than the other methods of extracting the WTP due to motivating the respondents (Lee and Han 2002). In this research Double bounded Dichotomous Choice (Hanemann 1994 and Carson 1985) questionnaire was designed to do the interview and to extract the respondents WTP to determine the conservation value of the region in order to make aware the respondents completely from the condition of hypothetical market. The questions of questionnaire were about the socio-economic characteristics affecting individual preference (Such as the age, gender, education, the number of family members and so on) and the WTP for each member of the family. Finally, the individual WTP was questioned using a Double bounded Dichotomous Choice. The simple random sampling method was used as for sampling in population
To determine the offered prices in the Double bounded Dichotomous Choice Method, 35 open-end questionnaires were completed and the respondents were asked about the maximum WTP. Finally, the offered prices were calculated. The WTP amount (middle, minimum and maximum) was obtained through asking the basic questions. In accordance with the statistical procedures, 20,000, 10,000, 20,000 Rials have been stated respectively as the middle, minimum and maximum offered prices to protect the Abar watershed of Shahrood. The Logit model parameters were estimated using maximum likelihood by Shazam software.
Discussion ofResultThe results have been presented 60% of the respondents were male and 80% of the respondents were married. The average age of the respondents was 37.4 years. The average of the variable of cost were 16.44 billion Rials per month. The average household size of the visitors of the region was 3.7 persons. Almost 1% of the respondents were members of the environmental organizations. The average number of the times that the region was visited was estimated to be 3.4. 18 % of the respondents declared their willingness to participate in the conservation of the region. Based on the results, most of the respondents stated that they are willing to pay to protect the vegetation cover in the region due to the regulatory functions of vegetation cover including climate regulation, carbon dioxide absorption, reducing soil erosion and so on. According to the results, the questions of the WTP are asked in this way that the middle option is firstly asked. If the respondents give a negative answer to the question, then the lowest offered price will be asked of the respondents and if the respondents give a positive answer, then the highest offered prices will be asked. Based on result, 63 individuals of the respondents (18%) are willing to pay for the conservation of Abar watershed.
Based on the logit model results, the coefficient of the variables of age and income are significant at the level of 1% and the variables of the financial Affordability, gender, married, cost, visit number and bid are significant at the level of 5% and effect on the willingness to pay. Based on the theory, the sign of the estimated coefficient of the bid is negative which indicates that if the offered price for protecting the area increases the probability of the acceptance for paying a given amount will decrease. LR test statistic was used in the Logit model to assess the significance of the whole model and goodness of fit. The amount of this statistic was 62.68. Being significant of this statistic indicates that the estimated model is significant in general. The results reveal that almost 91% of the respondents were correctly allocated to predicted WTP either yes or no in the model, indicating a relatively good fit to the data. Based on the results of the study, mean of willingness to pay for preserving was estimated about 10574 Rials and preservation value of family was about 126889 Rial in year. Also annually preservation value of watershed was about 27353.6 Million Rial in year.
Carrying out this study in the current situation is an important step to protect the protected areas and the natural resources and to move towards the sustainable development. The economic, political, and social planners and decision-makers always emphasize on the cost-benefit analysis in their decisions. Such analyses are based on the quantity and the monetary units. Therefore, the economic valuation of the protected areas is important and as long as the fans of the nature and its conservation cannot determine the value of the services based on the monetary units, the important services and functions of the protected areas and natural resources which are largely out of the market will be ignored. In terms of the management, results of this research are very hopeful especially because the results indicate that the natural resources and specially the Abar watershed are important for people. The results can justify planners, authorities, and policy makers to protect the quantity and quality of the natural resources and to prevent of putting aside the natural resources and the environment due to the lack of supporting by the governments.ConclusionsThe estimated economic conservation value does not represent the value of the entire ecosystem of the region. In the other words, the ecosystem of the study area has many other values that can be demonstrated. Some of them consist of the biological control of pests, pollination, water and soil conservation, medicinal plants and byproducts, capture and storage of carbon dioxide and producing the oxygen, biological diversity, preventing soil erosion, combating with the air pollution, reducing the noise, adjusting and softening the climate, creating green space and landscape and natural scenery, increasing the groundwater resources and flowingly the springs and rivers, and so on that their values should be estimated.Keywords: willingness to pay, contingent valuation method, Semnan province, preservation value
Pages 85-98IntroductionThe use of energy input in addition to physical inputs cause pollution and greenhouse gas emissions such as carbon dioxide. Therefore, the energy consumption in the process of production of agricultural products will be accompanied by the release of carbon dioxide. Energy consumption at all stages of the supply chain of a product is of utmost importance and its use is associated with externalities. These effects can also occur in the product distribution. Internalizing these external effects involves estimating the environmental damages caused by economic activities, so product prices are more transparent and can also cover social preferences after internalization. On the other hand, the lack of equality between supply and demand of food products in each region and the distance between production areas and consumption areas, trade, and its distribution become inevitable among different regions. Road transport causes side effects that greenhouse gas emissions are one of its varieties.
Wheat as the main product in the Iranians food basket devoted 51.2 percent of the acreage to crops. This acreage in the 2013-2014 crop years produced 10.58 million tons. Although that energy consumption in the transport sector in the period 2000 to 2014 has increased by 1.86 times, carbon dioxide emissions has been at a rate of 2.04 times. Accordingly, emissions increased according to per unit fuel consumption. As a result, taking environmental control policies in this sector become inevitable. The calculation of environmental impacts that arise as a result of wheat movement can play an important role in managing green supply chain.MethodologyThe aim of this study was to estimate the value of the shade of environmental emissions in the production and distribution chain of the wheat in Iran. So, the amount of energy consumed in the production of wheat and distribution in the country is estimated for the years 2000 to 2014. Then, using a distance function based approach to estimate carbon dioxide emissions shadow price of wheat has been manufacturing and distribution sectors. A unique feature of this study was to evaluate and compare the importance of each part of the supply chain on environmental emissions.ResultShadow price of emissions should be achieved in order to internalize the externalities. One way to obtain this shade value is to estimate the distance at which communication between desirable and undesirable outputs is determined. According to what was presented in the research method, the carbon dioxide emission in the production process is less than the distribution process. According to research findings, 1.4 tons of carbon dioxide emissions occur for per hectare wheat production in the country, but in exchange for the distribution of this amount of wheat the emissions will reach to 2.03 tons. Total emissions in total production and distribution will be equal to 3.43 tons per hectare. These results can show the more importance of the distribution sector in the environmental damages.
According to the calculations of the current research, the ratio of CO2 shadow price in production sector is 1.4 percent of the cost of production per hectare at average, but this number reaches 15.3 percent in the process of distribution which indicating a much higher importance of the distribution process in CO2 emissions. The control policies in the distribution process of products will be more efficient and more effective in the distribution process. On average in the years 2000 to 2014, it had a value of 852400 Rials. This value in the production sector was equivalent to 76300 Rials. Hence the importance of distribution segment in carbon dioxide emissions is 11.2 times the production of wheat. The shadow value in the distribution sector of the real prices was higher than the value of shadow prices in the production sector. The shadow price of CO2 emission in production and distribution sectors has been ascending, but since 2010 and the release of energy prices, has been an incremental process. Another interesting point is that this increasing process is also shown once again on the implementation of the second phase of the release of energy prices.
As it is known, the production and distribution of wheat is accompanied by social losses imposed on the community. These environmental damages are not included in the economic calculations. The total amount of damages is 16.7 percent of the wheat production cost. The consideration of this damages can change the comparative advantage of wheat production in Iran.ConclusionGreen supply chain management requires that environmental impacts be taken into account in the production, distribution and consumption of goods. The first step is to calculate the quantity amount of environmental impacts in the supply chain. The carbon dioxide emission, as a result of energy consumption, is one of the major pollutants that are released in the environment. On the other hand, wheat as a strategic commodity plays a major role in in Irans food security. Therefore, the purpose of this study is to estimate the shadow price of carbon dioxide emissions in Iran's wheat production and distribution sector by using the Input Distance Function. The shadow value of the CO2 emission can be considered a green tax. The results of the research showed that the shadow price of CO2 emissions in the production sector is much lower than in the distribution sector. Also, the ratio of income to the cost of wheat production in Iran during the study period was 1.55. If the amount of environmental damage is taken into account during this period, this will be reduced to 1.33. Therefore, environmental considerations must be taken into account in the production and distribution of wheat.Keywords: Wheat, Pollution Shadow Price, Input Distance Function, Production, Distribution Chain
Pages 99-111IntroductionThe soil is the bedrock of all human productive activities and the foundations of many of the great and ancient civilizations that have maintained soil conservation. Population growth and shortage of new land for agriculture, large areas of forests have become degraded and transformed into agricultural land and, consequently, agricultural land has become industrial and urban. The major impact of land use change on the physical and social environment is an incentive for research in relation to the reasons for land use change and its effects. Modeling and analyzing these factors can help to plan and plan agricultural land. One of the issues that have faced many problems in developing countries over the last few decades, the growing urbanization and urbanization that have led to the emergence of huge immigration trends in urban areas around the world. Immigration to cities in these countries has caused such problems as incompatibility in utilization, urban environs, and the lack of urban services to immigrants, the creation of marginalization, the destruction of agricultural lands around urban development, and the modification of its use to industrial and urban uses. In Iran, as in other developing countries, this trend has existed.
On the other hand, the lack of serious attention to rural areas and agriculture, as well as the reduction of the share of villages and rural areas in the strategies of economic development and industrial development has caused the productive forces of these points to be able to provide livelihoods and to cities And areas around cities. Investigating the changes in land cover and land use from distant lands on the surface of the earth, which is usually made in two ways the first type is the changes that are made by natural factors such as erosion and flood occurrence, and the second type is the changes that occur by humans. Recently, in most parts of the world, human activities have been one of the main factors influencing land use change.Materials and MethodsThe data required for this study was completed by collecting 70 questionnaires in 2017. In the two-stage Hackman model, factors that can affect farmer's decision to change land management practices in agriculture, in the form of independent variables in the probit pattern and the factors that can affect the amount of change in use, in the set of independent variables in the linear regression model.
The second pattern is added by adding a new variable called MRI (IMR), which is constructed using the parameters, met the first pattern. The set of independent variables will be linked to the first stage. The dependent variable in the probit pattern consists of a binary variable with values 1 and zero. Accordingly, the dependent variable is the vector of the values 0 and 1 in which the number 1 is the decision to carry out the activity and the zero number means the decision to not perform that activity. This variable is based on the dependent variable in the Tobit model. Hence, for Yi whose value is greater than zero, the number 1 is set to zero, and for Yi whose value is zero, it remains zero. In this way, the independent variable of the probit pattern is constructed for all observations.
In the above models, β coefficients of pattern parameters, IMR Reverse Mills Ratio, V and Ei are error sentences. In the first step, the Hackman method, the probit pattern is estimated using the maximum exponential method.
In the second step, the Hackman method, The linear regression model is estimated for observations whose Yi is greater than zero¡ At this stage, the inverse of the Mills ratio is added to the set of independent variables in the regression model. The coefficient of this variable expresses the error caused by the sample selection. If the coefficient of this variable is statistically larger than zero, Deleting the zero views from the set of views will cause the skew of the estimated parameters of the template and if the coefficient of this variable is not meaningful, Deleting zero observations, although not leading to the error of the estimated parameters, But it will lead to the loss of performance of the estimator. The presence of the inverse of the Mills ratio in the linear regression model eliminates the existence of the heterogeneity of the primary model variance and allows the use of OLS. Therefore, it is possible to differentiate factors affecting agricultural land use change from the impact of factors on agricultural land use change. Static software has been used to estimate the two-stage Heckman model in this study.
Discussion of Results &ConclusionThe first phase of the Hackman's two-stage method is the decision stage to make land use change.
In other words, this is the stage of the intention. Based final effects of significant variables with positive effect, with an increase in the number of farmers in the family, assuming that other factors are constant, The probability of a decision to change the use of agricultural land increases by 0.18 units. For the variable number of agricultural land plots, one increase in the number of land shares, the willingness to decide to change the use of agricultural land is increased by 0.53 units. Also, the level of education and literacy level of a farmer increases by one unit (for example, one section) in his education, his desire to increase the change of user by as much as 0.23 unit's increases. In general, for the variables mentioned, we can say that the population of the farmer's family, The number of land plots and farmer education levels have a direct relationship with the farmer's willingness and decision to change their utilities That is, with the increase, the change in agricultural land use is also increasing. On the other hand, regarding meaningful variables with negative effect and their final effect, it can be concluded that farmer's income has a negative effect on agricultural land use change so that by increasing one unit in farmer's income, assuming that other factors are constant, the person's desire to change the use of agricultural land is reduced by 0.8 units. In other words, in summary, one can say that income, The price of a major agricultural product and the amount of rainfall have a negative relationship with the change in agricultural land use Namely, as these three factors are strengthened, the willingness of the farmer to change the use of agricultural land will be less. According to the results obtained from the probit model, the coefficient of determination of the Mac-Faden model is 0.48 and false R ^ 2 is equal to 0.61, which shows good fit of the model. Therefore, these variables in the second stage of the model are estimated to The OLS method is eliminated, and the number of altered agricultural land lots in the second stage is considered as a dependent variable.
In the second Hackman stage, the presence of the Mills Image Ratio (IMR) in linear regression eliminates the model's heterogeneity and makes use of the linear pattern and serves as a variable in the model.
According to the findings of this research, in order to solve the problem of agricultural land use change, proper control and planning in relation to urban migration and urban areas, To create more incentives for the farmer through appropriate policies in the price of products, Encouraging the farmer to use high-yielding inputs to earn more money, Provide water resources management policies for farmers to better access and use water resources and adopt policies to reduce farmer's costs of production in all areas, Shipping costs and initial charges are offered.Keywords: Land, change, Torbat Hydarie, Heckman Tobit Model
Pages 113-129Green plans are among natural blessings which have many functions toward air quality improvement. On the one hand, plants moderate the air pollutants by photosynthesis; and on the other, beautify the cities. Many other functions have been found for the trees, of course, including the absorption of sound, water and soil pollutions. For this reason, in many nations, the creation of a green belt for inside and outside the cities has been set forth as a serious requirement but in the implementation of such projects, it is a must to select the species to be planted. The authors studies indicate that so far, no investigation has been done toward the selection of tree species across the city of Ahwaz [Iran]. This is a city with a hot, arid climate where the temperature rises to 57 degrees Celsius in the summer; and suffers from many environmental problems such as particulates and industrial pollutions. But the landscape planners in the city of Ahwaz are confused and occasionally, the expenses for planting trees are made with little efficiency. The selection of the best air pollution-reducing tree species may help policy makers toward optimal allocation of their limited resources. On the other hand, the budget allocated to the Organization for Landscapes and Parks of Ahwaz City Hall is not proportional to the economic benefits of the real interests of urban landscape. Achieving economic benefits of the best pollution-absorbing tree species may be used as a scientific criterion for optimal allocation of funds to this organization. Also, using the results of this study, the citizens awareness of the importance of trees is improved which could result in a more friendly treatment of landscape on their part and prevent the cutting of trees for banal reasons.
So far, many studies have been performed in various nations toward valuation and appreciation of natural and environmental resources such as parks, forests, lagoons, etc. (Juutien et al., 2011; Jenkins et al., 2010; Westerberg et al., 2010; Setlhogile et al., 2011; Cui et al., 2012; Newell and Swallow, 2013). However, to the authors experience, no studies have been done so far appreciating a tree species which might have the most attractive ability in absorbing air pollutants concerning the city of Ahwaz. Additionally, in most studies, the figures obtained for the tendency toward final payment have not been generalized to the overall community benefitting from the advantages; and therefore, the value of natural resources have not been calculated as a natural capital. Moreover, the contribution of natural resource functions value in the provincial, regional, or national gross production has not been considered; which is a very important factor in funds allocation and also in the movement toward national green accounting and environmental evaluation of projects.Materials And MethodsThe methods applied in this study is the choice modeling method, which assumes the individuals to have a rational behavior so that by choice, they would maximize their desirability considering the budget constraint. Therefore, it is assumed that any respondent has a random desirability function (Ben-Akiva, 1985). A random desirability function consists of a specific, observable component and a random one (Montazer-hojjat and Mansoori, 2016). A random parameter logit model would be suitable to explain such conditions:Where um is the desirability of the nth individual, a binary variable; P, the protection cost for tree species or their improvement across the city; Ai, selected quality features of the tree such as air and sound pollution absorption, providing a delightful natural landscape, and educational services; Aisocij, an action variable of socio-economic characteristics of respondents and quality features of the intended tree species. Obviously, the socioeconomic characteristics of individuals are fixed at the time of their selection among the options and therefore, they appear in the model in action form with the features of tree species. After estimating the above model, the tendency toward final payment is obtained through dividing the estimated coefficient for each feature (i) by the estimated price coefficient (1):However, an important stage of this study has been the selection method for the best air-and-sound pollution-absorbent tree species as well as the field survey method applied in this section. For this purpose, three species with the highest frequency across the city of Ahwaz, Concarpus Erectus, Albiza Lebbeck, and Eucalyptus Globulus, were selected based on the data provided by the Parks and Landscapes Organization. To select the superior species in terms of air and sound pollution absorption, the Air Pollution Tolerance Index (APTI) was applied. This index is calculated using four parameters, namely, total chlorophyll, leaf extract pH, relative water content, and acid ascorbic concentration) (Pathak et al., 2011). To perform laboratory process and calculate the APTI, the sampling process from the leaves of selected trees was performed in five highly trafficked areas, namely, north (Kianpars), south (Golestan), east (Zeytoon Kargari), west (Kamploo), and downtown Ahwaz (Amaniyeh), randomly.
Leaves from three selected species were collected in three different time frames during June 2015; and for each species in each area, three plants were sampled randomly as replicas. Coevality of the trees, given the commensuteness in diameter and length of their trunks was also taken into account. Leaves collected in frozen environment (zero degrees Celsius) were directly transported to the laboratory.
Later, relative moisture and pH of leaf extract were measured. In order to measure other parameters, collected leaves were stored in zero degree Celsius conditions so that their properties would not change. Ultimately, the figures obtained from the experiments were fed into SPSS21 software for analysis.
Discussion of Results andConclusionThe results obtained from the measurement of five parameters, i.e. pH, RWC, ASC, CHL, and APTI, for three selected tree species, led to the selection of Albiza Lebbeck as the superior species in terms of air and sound pollution tolerance/absorption. The benefits of this species were also calculated for city residents. Tendency to final payment for four functions of this species was obtained dividing estimated coefficient for each feature by the price coefficient. They include tendency to final payment for natural landscape (Rials 1,418,128.4); reduced air pollution (Rials 1,692,708.9); reduced sound pollution (Rials 1,770,981); and educational performance (Rials 1,653,938.4). Additionally, the annual value of benefits and capital value of this species were calculated to be Rials 1,167 and 1,852 B, respectively.
Using the figures obtained for annual value of social benefits of Albiza Lebbbeck species, the municipality of Ahwaz will be able to direct the budget of the Parks and Landscapes Organization toward higher efficiency; and to determine its budget based on every citizens landscape quota and the figures obtained by this study. Additionally, the municipality may use those numbers to determine the tendency of residents to pay renovation and building license charges; and to update previous numbers.
Given the results of this study and the enormous capability of Albiza Lebbeck in absorbing and metabolizing the pollutants, it is recommended that planting this species be included in agenda in highly trafficked areas of the city of Ahwaz such as the downtown, along city roads, industrial zones, factories, and other areas where there is a possibility of air pollution. Also, by using the results of this study and the obtained figures, it is possible to improve social awareness on real value of this species functions, enhancing their sense of responsibility to protect it, and to prevent their unnecessary cutting. Also, the results of this study can be used as a basis to fine the breaching citizens for cutting the trees. Another use for the results of this study is in the field of economic-environmental evaluation of urban projects. The figures obtained by this study can be used to evaluate the projects which might require cutting the trees. Thereby, environmental costs will be included in calculations; and the justification for some projects might even be questioned.Keywords: Choices modeling, marginal willingness to pay, environmental capital value APTI
Investigation and Comparison of the Economic Value of Carbon Sequestration Function of Vegetation Cover in Biological Operations (Case study: Sarbishe Rangelands-South Khorasan Province)Pages 131-148One of the most important ecological functions of rangelands especially destroyed rangelands is the high potential of carbon sequestration as the most important greenhouse gasses. Restoration of destroyed Irans dry lands has an important role in environmental plans. So this study was aimed to investigate the effect of range plants vegetation recovery operations on the economic value of carbon sequestration. For this purpose, three types of restoration plans, the construction of shrub planting, seeding and crescent waterfall, besides control sited were identified. The carbon tax policy method was used to estimate the amount of carbon sequestrated. According to the results, the carbon capture rate in the rangelands of the study area was estimated at 774 tons. The value of each hectare of the rangelands for carbon sequestration function estimated at $17.35 (equivalent to $ 60,744). According to the results, management factors such as recovery operations have played an important role in controlling carbon sequestration. Also, the treatment of carbon sequestration activity of the brush planting, significantly improved the ecological indices and the value of carbon sequestration compared to the control areas.IntroductionRangeland ecosystems have high capability in carbon sequestration, because they have taken half of the surface of the earth and their carbon storage accounts for 10% of the total carbon stock of biomass in ecosystems and 30% of total soil carbon stock. However, carbon sequestration capacity in rangelands is less than forests, but due to the large extent of these ecosystems, management of these areas plays an important role in the carbon cycle. For this reason carbon sequestration in addition to the protective value has an economic value and it can be as an additional benefit of destruction operation of destroyed lands. Destruction operations such as restoration and protection of vegetation of pastures to increase carbon sequestration in soil and plant has other benefits such as ecosystem services. To increase carbon sequestration in arid and semi-arid regions planting methods are usually used. Using bush plants by deep root can absorb water from deep soil which normally is not available by existing plants in this areas. Su-Yong and Zao (2003), Hill et al (2003); Schuman and Derner (2007) stated management factors has an important role in soil carbon sequestration and the result of their research showed that under managed range management systems, total soil carbon sequestration, has increased significantly in biomass, litter and soil. So, increasing carbon sequestration through vegetation regeneration is equivalent to increasing plant biomass, increase production and improving land fertility. For this reason, in addition to basic and protective values, has also economically value. Considering the growing importance of greenhouse gases in the world and the importance issue of global warming and increasing co2 is not applicable to a particular country, there are a lot of ambiguous issues related to the ability of the types and different range plants in soil carbon sequestration and their economic value. Responding to these issues depends on extensive researches. Therefore, the present study aims to estimate and comparison the economic value of succeeded aboveground biomass of range plants.Materials and MethodsHossein-Abad basin is located 40 km away from Sarbishe city, in the south khorasan province adjacent to the Afghanistan border. In order to compare destruction operation 3 sites were selected. The sites located at Hossein-Abad in 79° 90' - 80° 55' E and 36° 01' and 36° 04' N, Abbas-Abad in 78° 65' - 78° 79' E and 36° 08'- 36° 11 N', Janat Abad in 78° 20'-78° 50' E and 36° 07'- 36° 09' N were selected. The average elevation of the area is 1830 m. Hossein-Abad rangelands receives an annual precipitation of 188 mm and its average annual temperature approximate 14.5 C°. To measure carbon sequestration in plant, 3 transect 200 m at a distance of 30 meters from each other were established. 10 (3m2) were established in each transect. Specified herbaceous species and their density were measured. To determine the coefficient of carbon sequestration of species into organic carbon, the combustion method was used. The ash of the samples was weighed after cooling in the desiccator. By determining the weight of the ash and with the weight of the original and the ratio of organic carbon to organic matter the amount of organic carbon in each of the plant organs was calculated separately. For valuing carbon sequestration function, carbon tax policy and the cost of emissions was used as a shadow value for carbon sequestration.
Discussion ofResultsThere was a significant difference in comparison of the mean of destruction operations with control area in terms of percentage of vegetation, forage production and litter indicators table (1), (2) and (3).
Table (1)- t test results for shrub destruction operations and control area
Feature Degrees of freedom
Plant vegetation cover 58 17.1**
Forage production 58 10.8**
Litter percentage 58 19**
Table (2)- t test results for crescent waterfall destruction operations and control area
Feature Degrees of freedom
Plant vegetation cover 58 13.9**
Forage production 58 11.3**
Litter percentage 58 9.3**
Table (3)- t test results for seeding operations and control area
Feature Degrees of freedom
Plant vegetation cover 58 13.6**
Forage production 58 7.3**
Litter percentage 58 13.1**
The results of the variance analysis between destruction operations and control sites forage production showed that there was significant difference between the sites of carbon sequestration project and the control site.
Table (4)- Analysis of variance of site type and destruction operations on organic carbon
Feature Degrees of freedom Mean squares
Site 1 7670.1 **378.5
Kinds of destruction operations 2 172.5 8.5*
error 176 20.2
- Carbon sequestration in plant
Results of carbon sequestration in plant has shown in table (5). In organic carbon construction operation, dominant plants in shrub planting operation were Atriplex canescen, Haloxylon persicum, Artemisia sieberi, Zygophyllum atripoides.
sites Kind of operation Area (ha) Dominant plant Density (ha) Average carbon in plants (gr) Total organic carbon in plant (ha)
organic carbon (kg/ha)
($/ton) Total organic carbon (ton)
Destruction operation site Shrub
planting 1472 A.Canesces 209 133.61 27.92 343 8.67 504.8
P. Haloxylon 213 254.81 54.27
A.sieberi 10520 21.2 223
z. atripoides 268 141.1 37.81
Crescent waterfall 1311 A.Canesces 155 129.6 20.08 220 5.56 288.4
P. Haloxylon 218 238.3 51.94
A.sieberi 7150 20.7 148
Seeding 370 P. Haloxylon 280 240.6 67.3 171 4.32 63.2
A.sieberi 6030 17.2 103.7
Control site Shrub
planting 1472 A.sieberi 1653 9.4 15.53 41.75 10.5 61.4
A.camelorum 2081 12.6 26.22
Crescent waterfall 1311 A.sieberi 652 6.5 4.23 12.64 3.18 16.57
A.camelorum 956 8.8 8.41
Seeding 370 A.sieberi 709 7.2 5.1 11.79 2.9 4.36
A.camelorum 1015 6.6 6.69
- Valuing Carbon sequestration in plant
Table (6)- Comparison of carbon sequestration levels and its economic value
sites Total organic carbon (ton) Total Economic value of C ($/ton/yr) Total Economic value of C (Rial/ton/yr) Economic value of C sequestration (Rial/ha/yr)
Destruction operation site 856.4 60547.48 211916180 67210.96
Control site 82.33 5820.73 203725550 64613.24
Carbon sequestrated weigh 774 5421.8 191526300 60744.15ConclusionsIn this study, to estimate the amount of carbon sequestrated in the plant, considering the cost of measurement, only the dominant species of rangelands of the region were measured. So, it is recommended to measure a whole plant species c sequestration in the region. Also, in selecting suitable species for destruction operations the ability of species in carbon sequestration is one of the indices for selecting the appropriate specie. Considering different valuation methods, it is suggested that the economic value of carbon sequestration in the study area compare with other methods of economic valuation and their results with each other.Keywords: SOC sequestration, construction operation, plant vegetation, economic value, steppe rangelands
Evaluation and Determination of Urban Land use Resilience based on Sustainable Development Approach (Case Study: District One of Tehran Municipality)Pages 149-169IntroductionLooking at the long history (at least ten thousand years) of human settlement, we can realize that urban environments in their current shape and form can be considered a relatively new phenomenon.Despite covering a small area of the earths surface, urban environments house the majority of human population. This high concentration of population on one hand escalates the exposure to natural or man-made disasters and on the other hand increasesthe vulnerability of urban communities, especially in developing countries. Movingthe entirepopulationout of the danger zones is an impossible task; therefore a set of structural and non-structural measures must be taken to make the settlements morehazard-resilient. Land use planning,as one the most important tools of urban planning, can play a significant role in reducing the disaster risks.
Tehrans district 1 hasa high concentration of population and is house toseveral administrative and economic centers, but its geological and geographical characteristics make it highly exposed to natural and man-made hazards,which overall make this district an ideal subject for a case study.So the present study aims to determine and clarify the dimensions and criteria of urban land use resilience, and to measure and evaluate these dimensions and criteria for Tehrans district 1, in order to take effective steps toward reducing the vulnerability and improving the resilience of the study area.
Theoretical principles of research:Numerous studies have been carried out to determine the relation of resilience dimensions and components with the urban land use. In the end, severaldimensions and criteriaconsidered more prominent bythe experts (specializing in the field of environmental planning, urban planning,and geography) have been proposed for the concept of land use resilience.The dimensions of urban land use resilience are listed in Table 1.
Table 1. the dimensions of urban land use resilience.
Structural-natural dimension is among the main measures of a resilient community, and describes the various structural-natural capacities of a city or a district affecting its ability to prevent and withstand the crisis and its quick return to normal status after the crisis. Any city or district lacking structuralnatural resilience will have a very low environmental quality and will be very vulnerable in the face of a disaster.The structural-physical dimension is another main aspect of urban land use resilience. Improving the resilience of cities in this aspect is an appropriate and effective way to strengthen the city to deal with crises and natural and unnatural hazards. Paying proper attention to this aspect increases the quality of normal city life before the crisis, reduces the damage and casualties in the event of crisis, and accelerates the return to normal conditions after the crisis by speeding up the relief and aid efforts. Another important aspect of urban land use resilience is its socio-cultural dimension. Paying proper attention to the socio-cultural aspects of urban land use resilience increases the environmental quality and improves the lives of citizens. Another advantage of socio-cultural dimension of resilience is its ability toincrease the mental, psychological, and spiritual readiness of citizensagainst the events that happens before, during and after the crisis. The economic dimension is another key aspect of urban land use resilience. Economic resilience describes the economic capacity of a region to prevent and withstand the crisis andto make a quick return to normal status after the crisis. Any city lacking the economic resilience will be highly vulnerable to natural and unnatural disasters and will not be able to quickly return to equilibrium after the crisis.
The study area:The study area is thefirst district of Tehran municipality.Given the current Tehran northern borders approved by Tehran City Council, the area of this district is 4574.24 hectares. This district is bounded by 1800mcontour line of the southern slopes of the Alborz Mountains in the north, by the Chamran highway (between Hotel Azadi and Sadr bridge)in the south, by Darakeh river basin in the west, and by the Artesh highway, cement factory, andTehransnortheast oil depot in the east.
ResearchMethodologyAt the first step of this research, the theoretical framework was determined by collecting data fromlibrary and electronic resourcesand related articles. Then the important criteria and sub-criteria for assessing the urban land use resilience were determined by incorporating the expert opinions and reviewing the previous research. Then the FAHP method, which incorporated the opinions of 15 experts and faculty members in the field of environmental planning, urban planning, rural planning and urban development, was used to make pairwise comparison between important dimensions and criteria. At this stage, all valuations were based on experiences and studies of those experts. After making pairwise comparisons, the maps of district resilience factors were standardized in Idrisi environment , and then the weight of each resilience factor was applied to the layers in the GIS environment. The maps were then merged to determine the resilience of the district, and finally the TOPSIS technique was used to prioritize the resilience of each zone within the district.
Discussion andConclusionIn this study, first the factors affecting the resilience of land use were examined, and then these factors were evaluated for Tehrans district 1.The results of these evaluations showed thataverage resilience of this area is approximately 0.61which indicates that this district is moderately resilient (moderately vulnerable).Therefore, according to the research findings the following results can be concluded:1- According to experts opinions, the structural-physical dimension plays the most important role in enhancing the urban resilience. In this dimension, the criteria of buildings condition, access routes, high-risk land uses, public safety land uses, green open spaces, and quality of residential centers were evaluated. Ultimately,district 1 gained an average resiliency score of 0.53 in this dimension, which indicate a medium resilience (or medium vulnerability) with respect to this dimension.
2- According to experts opinions, the socio-cultural dimension also plays an important role in enhancing the urban resilience. This dimension consisted of 8 criteria including population density, and land uses related to healthcare, education, culture, tourism, sports, law enforcement, and religion. After overlaying all layers corresponding to criteria, district 1 gained an average resiliency score of 0.69, which indicate the resilience of this district with respect to this dimension.
3- The structural-natural dimension was placed third in terms ofimportance in enhancing the urban resilience. The criteria of this dimension included natural hazards, composition and distribution, vegetation, and physiography. District 1 gained an average resiliency score of 0.78 in this dimension, which indicate the resilience of this district with respect to this dimension.
4- The economic dimension included the criteria of commercial land uses, economic activity, employment and unemployment.Assessments in relation to this dimension revealed thatDistrict 1 has an average resiliency score of 0.47, which indicate the medium resilience (or medium vulnerability) of this district with respect to this dimension.Keywords: metropolises, resilience, urban land use, sustainable development
The factors affecting on forming and development of Tehran with an emphasis on relationship between city and naturePages 171-188Before Qajar era, Tehran City located beside Rey was a borough with favorable weather. At the time, Iranian kings used the borough as a temporary residence. Gradually, kings paid more attention to the borough since it contained green gardens and areas with desirable weather. In Qajar era, announcement of the city as countrys capital enabled its further development and physical growth.
Based on works of travelers and historians published during different historical era, the word garden preceded the name Tehran to describe it. The review of historical texts shows that one of the early gardens made before civilization and urbanization of Tehran City covered Golestan Garden as well as districts between Org Square and Panzdah-Khordad St. in South, Naser Khosro in East, Khayam St. in West and Imam Square and Imam St. in North.
Based on historical documents, up to middle years of Nasser al-Din Shahs reign Tehran City physically grew along its eastern-western sides and near Tahmasbi borderline. In late years of the era, the borderline was taken down and city grew northwards towards Alborz mountain skirts and Darvazeh Dolat. However, the mutual association between Golestan Garden and Tehran city or effect of the garden on development and growth of the city has not been studied yet. In other words, review of literature of development and growth of Tehran City showed that role of garden as natural contributor to and main factor affecting development and growth of the city has not been studied yet. From Iranian architectural viewpoint, architecture develops out of garden. This significant factor (i.e. garden) could be studied in relation to Tehran City. In other words, effect of historical garden of the city, as city was previously a borough and had a garden in it, could be reviewed further.
The studies of historical maps signified the importance of Golestan garden in Tehran village as well as effect of garden, as primary nucleus of the city, on development and growth of Tehran City.
Therefore, the present paper seeks to suggest that the main factor affecting development, growth and orientation of Tehran City is Golestan garden. In addition, it is endeavored to suggest that natural setting (i.e. garden), city and architecture are mutually related.
In order to conduct the study, the following questions should be explained.
Q.1-Could one state that Tehran City was developed out of the garden?
Q.2-Did development of Tehran city arise out of the garden?
Q.3-What is the role of Golestan garden in the association?
In this paper, it is presumed that there is a direct association between garden and development of the city. In addition, association between physical growth of Tehran City and its natural setting and gardens (especially Golestan garden) is hypothesized. Temporal changes of the garden and its internal constructions exert effect on the city and its development as long as the garden is not torn into pieces. Since garden acted as an element directing the city towards outside of its boundary wall, the gardens located out of the city, north and skirts of Alborz mountains, the present paper intends to highlight the mutual effects of natural setting (i.e. garden), city and architecture on each other.
From a natural viewpoint, analysis of natural and historical layers of the city as well as its natural setting offers a reasonable and scientific method for studying development and growth of the city. In the present paper, the method is adopted to evaluate and document the association between Tehran City and natural factors.
To real the research objectives, historical texts should be reviewed to highlight the associations between trend of urban changes and garden, garden and architecture, and architecture and decorations. Based on this method, collection and review of all relevant documents, historical documents, travel books, and relevant images are done to collect the necessary information on above associations. Then, review of those studies may offer layers of information for further analysis of trend of growth and development of Tehran City as well as its association with natural factors and setting. Consequently, data collection is followed by study of the associations of garden, city, architecture, and natural setting. Finally, a hermeneutic approach is adopted to analyze the data qualitatively.
The findings suggest that primary core of Tehran City was made up of vegetation and direction of water networks (aqueducts) at the skirts of Alborz mountains. One of the gardens exerting higher effect on the urban development is Golestan garden. Physical growth of the city is correlated with lower number of these gardens while such gardens increase in number northwards and out of Tehran City. In general, one may suggest that in its initial steps of development, Tehran had a direct correlation with natural elements and the association continued until Pahlavi era. The interaction between city and its natural setting could be categorized into three major parts: association between nature and city in a macro-scale, association between nature and architecture in a medium scale, and association between decoration and nature in a micro-scale.
In a macro-scale, the garden contributed to development of the city, its changes and future trends. In a medium scale, Golestan garden and its internal set of buildings act as a city within another city. In such a case, the initial core of the city is its garden and it grows northward. In the case of development and internal change of the city, priorities were maintaining geometrics of the garden, keeping its square and rectangular shape (principles of developing Iranian gardens) and building architectural spaces. On the other hand, change in view of inner-city gardens to skirts of Alborz mountains and remote vistas during Qajar era led to directing the growth of buildings inside the garden and development of the city northward (i.e. towards mountain skirts). In a small scale, significance of nature and natural elements such as tree, plants and water is vivid. In this case, tile and painting decorations use such elements when royal and luxury settings are concerned.Keywords: Golestan Garden, Urban Development, the Royal Palace, Tehran city, natural context
Analysis of the Effect of Land Cover Spatial Configuration and Physical Characteristics of Buildings on the Surface Urban Cool Island PhenomenonPages 189-203IntroductionThe expansion of metropolitan areas has led to several physical, socioeconomic and environmental issues. One of the negative consequences is the intensification of urban heat islands (UHI) phenomenon in areas with more moderate climate. Studies on surface UHI have shown that in more arid environments there is a possibility for urban areas to have a lower temperature than the surroundings; a phenomenon that is called surface urban cool islands (SUCI) or surface urban heat sink.
Studies on the SUHI have shown that in addition to spatial composition and abundance of land covers, the shape of a land cover and its relative placement to other land covers (spatial configuration) is also important. These studies have pointed out that the land surface temperature (LST) decreases, as the complexity of urban patches in more moderate areas increase. However, studies on SUCI have mainly focused their attention on analyzing the effect of time of data acquisition and also the influence of the composition of land covers on the land surface temperature.
Another matter that has been somehow forgotten is the effect of building density and plot size on LST. Previous studies have noted the positive impact of the increase in building density on LST. However, the effect of plot size on the SUCI phenomenon has been significantly neglected.
Therefore, the purpose of this study is twofold. First, it tries to investigate the role of spatial configuration of land covers in the formation of SUCI in Shiraz urban area and then to assess the effect of urban density and plot size on the intensification on SUCI.Materials And MethodsThe process of the study involved three stages. First, the SUCI intensity for four different seasons was studied to determine if the SUCI phenomenon can be seen in Shiraz. Then, by conducting linear regression and with the use of landscape metrics, the relationship between the mean LST and the shape complexity and fragmentation of land covers was examined. Afterwards the effect of building density and plot size of the mean LST was studied.
Shiraz, the fifth largest city of Iran in terms of population with 1.869 million, has a hot semi-arid climate according to the Köppen climate classification.
2.1 Retrieval of LST
The methodology proposed by Sobrino et al. (2004) and Sobrino et al. (2008) were used to retrive LST for each year from the thermal bands of the images (band 6 of Landsat TM). It should be noted that the land surface emissivity was calculated for the thermal band with the simplified of Normalized Difference Vegetation Index (NDVI) Thresholds Method (NDVITHM).
2.2 SUCI intensity
A 10-km rural buffer around the core urban area which does not include water bodies were selected to compute the SUCI intensity.
2.3 Indicators to analyze the effect of landscape composition and spatial configuration and building characteristics on LST
The effect of landscape composition and spatial configuration on the intensification of SUCI was studied by using composition indices and landscape metrics. The composition indices, which are including NDVI and NDBI, measure the abundance of vegetation and non-vegetative land covers, respectively. Two metrics of Landscape Shape Index (LSI) and Fractal Dimension Index (FRAC) measure the shape complexity of land covers by studying the relative amount of perimeter per unit area, and Landscape Division Index (DIVISION) is the third spatial configuration index to study the degree to which land covers are broken up into separate patches.
The effect of building characteristics was also studied through examining the building density (Floor Area Ratio) and the size of plots in each census tract.
Discussion andResults3.1 SUCI intensity
There were distinctive temperature differences between urban areas and the surroundings throughout the year. Also the SUCI phenomenon in Shiraz was at the highest level in summer. While the SUCI intensity was 6.62 degrees in summer, it was 3.42 degrees at the lowest level in winter.
3.2 The effect of landscape composition on LST
The value of NDVI showed that vegetation had no effect on the reduction of LST in urban area of Shiraz. Although a great deal of vegetation of the study area is within conservation areas in a few census tracts which had lower LSTs. On the other hand, the NDBI represented a significant effect of the built-up area on reducing land surface temperatures, contrary to studies on urban heat islands.
3.3 The effect of shape complexity and fragmentation of built-up areas on LST
Examining the landscape metrics showed that as the complexity and fragmentation of urban patches increased, the mean LST of census tracts rose as well. The increase in shape complexity and fragmentation of urban patches means these urban patches will have more adjacency with other land covers (such as vegetation or soil) on their edges.
3.4 The effect of building characteristic on the intensification of SUCI
The value of FAR pointed out that as the building density of each census tract increased, the mean LST decreased. On the other hand, the smaller the size of plots in a census tract, the lower the mean LST was. This can be clearly seen in historical areas of Shiraz in which the size of plots is smaller.ConclusionThe results of this study revealed that the surface urban cool islands in Shiraz were significantly affected by the expansion of built-up areas. The analysis of landscape metrics showed as the built-up areas grew more irregularly, LST decreased. In other word, the shape complexity and fragmentation of urban patches led to an increase in LST. The shape complexity and fragmentation of urban patches means they have more adjacencies with other land covers such as vegetation. The analysis of building density and size of plots also showed the height of buildings and the size of plots affected the land surface temperature. In fact, the increase in building density and the decline in the size of plots led to the mitigation of LST and the intensification of SUCI. To sum up, while the expansion of built-up areas has a distinctive impact on mitigating LST, the SUCI phenomenon intensifies as this expansion occurs with higher density and in a smaller area.Keywords: Surface Urban Cool Islands, Land Surface Temperature, Landscape Metrics, Building Density, Plot size