فصلنامه سلامت و محیط زیست
سال نهم شماره 4 (پیاپی 34، زمستان 1395)

Street dust is consisting of solid particles with complex compositions which can be an appropriate indicator to determine urban environmental contamination. Therefore, the purpose of this study was to determine spatial patterns and heavy metals contamination in the street dusts of Kashan.
A total of 48 urban street dust samples were collected and total concentrations of Pb, Cu, Zn, Fe, Cr, Ni, and Cd were determined in the dust samples. The geoaccumulation index was applied to assess heavy metals contamination. In addition, the spatial patterns of heavy metals concentrations in the street dust were determined using GIS.
The results showed that the average concentrations of Zn, Cd, Cr, Fe, Ni, Pb and Cu in the street dust samples were 237.21, 0.43, 37.12, 16589.77, 13.62, 45.18 and 45.58 mg/kg, respectively. The average concentrations of Pb, Cu, Zn, and Fe were higher than their local background values. Based on geoaccumulation index, the heavy metals in the street dust were in the following decreasing order: Pb > Zn > Cu > Ni > Cd > Cr. According to the spatial analysis results, higher concentrations of heavy metals were observed in the city center and Kashan-Qom highway; whereas, lower concentrations were found in the residential regions.
Based on the obtained results, it seems the high concentrations of Pb, Zn and Cu and to a lesser extent Fe and Cd concentrations in the dust samples was derived from anthropogenic activities; whereas the concentration of Cr and Ni has been mostly affected by natural sources. The high concentrations of heavy metals in the street dusts of Kashan could be attributed to vehicle emissions and industrial activities.

Water corrosion and scaling are known as destructive phenomenon of drinking water quality and water facilities. In this study, the groundwater tendency to corrosion or scaling in source water, water storage reservoirs and distribution system were studied. Simultaneous use of some qualitative and a quantitative index along with statistical analyses to assess the water scaling or corrosion tendency were investigated.
The data analysis of groundwater, water storage reservoirs and water distribution system in rural area of Kurdistan province were analyzed and the amount of Langelier (LI), Ryznar (RY), Pockorius (PSI) and Larson–Skold (LS) and CCPP indices were determined. Corrosion and scaling threshold for qualitative indices were determined based on CCPP index. The mean of indices was compared with the thresholds using independent t-test. ANOVA was used to assess the difference between the indices in different sources of water.
The balance range for LI, RY and PSI found to be -0.1-0.05, 7-9 and 7.1-8.5. The mean CCPP for groundwater, reservoirs and networks were 9.27 ± 1.29, 9.13 ± 1.25, 11.25 ± 1.23, respectively. All three sources of water have some tendencies toward scaling; however, a significant balance status was confirmed statistically. According to Larson–Skold index, sulfate and chloride anions did not play a role in scaling process.
The use of qualitative indices with CCPP index can provide more accurate estimation of water tendency toward scaling or corrosion. The assessment of qualitative indices along with CCPP is recommended in drinking water corrosion monitoring studies.

The aim of present study was to assess environmental inequality in long-term exposure to outdoor air pollution in 22 districts of Tehran in 2012.
The present study is an ecological study and concentration index was used for assessment of inequality. In this study the amounts of pollutant concentrations (PM10, NO2, SO2) obtained were based on land use regression (LUR) for exposure assessment. Variables that their effects have been studied on the distribution of exposure to pollutants included: education level, employment status and car ownership, which were obtained from census demographic and Tehran Municipality's dataset.
The concentration index for PM10 in the case of illiteracy, people with higher education and private car owners was 0.059 (0.004-0.113), -0.056 (-0.001- -0.110) and -0.079 (-0.031- -0.127), respectively. These relationships were statistically significant. Concentration index for PM10 was 0.016 for the workers population, which was not statistically significant. For NO2 and SO2, no inequality was found in illiterate people, people with higher education, employees and car owners.
This study showed that there was significant inequality in terms of exposure to PM10 between different regions of Tehran in the illiterate, people with higher education and car owners. Considering these subgroups of population can be helpful in policy-making process.

Solid waste management has always been one of the major challenges of large cities. Conversion of waste to energy in the form of biogas is known to be an appropriate solution. The aim of this study was to investigate the effect of total solids (TS) content and alkaline pretreatment on biogas production from municipal solid waste (MSW).
Experiments were done in 1 L glass bottles at 37 °C with different TS contents (5, 10, and 15%), each in 3 replications based on a completely randomized design. Comparison of means was used for interpretations of the result. The volume of the produced biogas, the amount of methane, and changes in pH were measured on a daily basis. In order for better mixing, the digesters were manually shaken for 30 seconds every day. TS, volatile solids (VS), carbon and nitrogen of the feedstock were determined according to APHA standard methods.
The highest methane yield and VS reduction was observed in 5% TS. Therefore, this TS was chosen for alkaline pre-treatment. The results showed that pre-treatment with NaOH significantly improved biodegradability of MSW. In 25 days, the production of biogas was 30.38% higher than that of the untreated digester. The highest methane yield was 83.35 mL/g TS and 132 mL/g TS from the control and the pretreated digesters, respectively.
The results of the lab experiments showed that the TS of 5 % and the alkaline pre-treatment, significantly improved biodegradability of MSW and consequently increased biogas and methane yield.

Dewatered sewage sludge is a by-product of wastewater treatment process which can cause health and environmental problems if not properly managed. The aim of this study was to determine the feasibility of composting of Yazd WWT dewatered sludge with windrow method using different treatments.
In this study, the dewatered sewage sludge was mixed with two treatments of agricultural wastes (straw) and green waste (leaves), respectively. The mixture was done based on weight ratio of 20:1 and 10:1 (agricultural waste: dewatered sludge, and green waste: dewatered sludge) to achieve a ratio of C/N:20. The windrows were built with a length of 2 m, width of 75 cm and height of 1.5 m. Composting process was controlled by measuring the temperature, humidity, volatile solids, ash, pH, EC, organic carbon and estimating the C/N ratio. The results were compared with those of the Institute of Standards and Industrial Research of Iran.
After 100 days of composting, C/N ratio was 13.08±6.25 in the treatment with green waste and reached to 15.46±5.35 in the treatment with agricultural waste. The amount of volatile solids decreased to 19.8±14.01% and 20.71±16.06% in the treatments with green waste and agricultural waste, respectively. The amount of EC had an increasing trend in both treatments.
composting with both treatments was led to an improvement in indicators of organic fertilizers in dewatered sewage. However, the windrow containing green waste reached to the mature compost standards sooner than the windrow containing agricultural waste.

Malachite green dye is used in many industries including textile industries. Disposal of wastewaters containing the dye to the environment, can lead to many environmental problems. Currently, many physico-chemical approaches are used for wastewater treatment. Because of limitations and difficulties of these methods, biological treatment is considered as an economic and effective treatment method. The aim of the present study was to study the feasibility of phytoremediation of malachite green dye using watercress and investigate the effect of some environmental factors in removal efficiency.
After collection, the plants were kept in the laboratory, and they were treated with different concentrations of malachite green. During the experiments, decolorization extent was determined by UV-Vis spectrophotometry. Intermediate compounds generated during the biodegradation of the pollutant were identified using GC-MS method.
After 7 days, the ability of watercress in removal and biodegradation of 10 mg/L of malachite green solution was more than 90%. Five intermediate compounds were identified in the biodegradation pathway of the pollutant. It was also found that increasing dye concentration up to 20 mg/L led to the increase of the plant photosynthetic pigment contents and activities of antioxidant enzymes.
Our results showed that watercress has high ability in the dye removal of malachite green. The reusability of the plant for decolorization confirmed the biological degradation process. Moreover, an increase in the plant biomass, temperature and pH led to the increased decolorization efficiency.

The aim of this study was to investigate the physico-chemical properties, size distribution and shape of the falling mineral dusts over Masjed Soleyman and to identify their origins. Also, seasonal and annual variations of climatic parameters and their relation with dust storm occurrence were investigated.
The collected samples were as result of dry deposition process during warm season in 2013. Particle size distribution was determined by laser size diffraction. Chemical and mineralogical compositions were measured with atomic absorption spectrophotometer (AAS) and X-ray diffraction (XRD). Crustal and non-crustal origins for elements in the dust samples were determined using enrichment factor (EF). In addition, dust storm sources were identified using the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT.4).
The study of the annual and seasonal changes in meteorological parameters associated with the occurrence of dust storms indicated an agreement between the occurrence of dusty days, temperature and rainfall in summer. The chemical and mineralogical analysis of dust particles demonstrated that the likely origin of these particles is of neighboring countries in the South West of Iran. Also, some of the detected trace elements had non-crustal sources.
Using HYSPLIT.4 results, it was concluded that the main origin of dust storms are North West of Iraq and East of Syria in Masjed Soleyman.

There are major mobile and non-mobile pollution sources due to human activities that can influence aquifers and reduce groundwater quality. Vulnerability assessment is an inexpensive procedure in to identify areas prone to the pollutants. Identification of these sources is essential in water resources management. Mahidasht Plain is one of the important regions of Kermanshah province and plays a significant role in the production of agricultural products. Water supply for agriculture may be at risk due to the indiscriminate withdrawal of groundwater resources of the plains, the recent droughts and potable water requirements. Therefore, analysis and evaluation of the area helps to make better decisions on proper management and control of water pollution.
Vulnerability, which is defined as the sensitivity of groundwater quality to pollution load, was applied and determined using intrinsic features of the aquifer. In this study, we have studied inherent vulnerability of the Mahidasht aquifer against pollution by using DRASTIC model and GIS. Seven parameters for the zoning of aquifer vulnerability was used in the DRASTIC method, including depth to the water table, net recharge, aquifer material, soil type, topography, impact of vadose zone and hydraulic conductivity. These parameters were prepared as seven layers of information in Arc GIS10 Software. The data collected for the purpose of this study were taken fromwells log, 44 piezometer in the area, pumping experiments and three rain-gauge stations. The layers prepared in Arc GIS10 software were weighted, ranked and eventually integrated.
The DRASTIC index calculated for the plain ranged from 34 to 120 units. On this basis and according to the standards listed for DRASTIC index, the aquifer was in a vulnerable group with a low or no risk.
DRASTIC model output showed an inherent vulnerability of the aquifer. The model can be used as a primary tool in the development and management of water resources in the future. In addition, this model is not able to produce information about amount and type of pollutants. Therefore, it is recommended to examine the salinity zoning in the future research due to less rainfall and decreasing underground water level and consequently the higher probability of salinity in underground water. Additionally, the domestic and industrial wastewater, sewage irrigation and the fraction used for groundwater recharge should be considered in order to validate the results of Drastic model.

Arsenic accumulation in rice has become a major disaster in the recent decade. A number of studies indicated that rice is a major source of arsenic pollution in human diets. This study assessed the arsenic (As) accumulation in rice grain in Meydavood where rice is the main agricultural crop of the region. This research studied the probable presence of arsenic in the rice grains of Maydavood region in Khozestan province and evaluated the arsenic intake through daily rice consumption.
Ten rice samples were taken from Meydavood farms during cropping time. Samples were analyzed for arsenic using ICP-MS.
Data were analyzed using SPSS statistical software and then compared with the World Health Organization standards. The mean concentrations of arsenic in rice samples were 0.079 ppm based on dry weight. The results showed that in 30% of the samples, arsenic concentration exceeded the WHO standards. Due to the high concentration of arsenic in rice samples, the arsenic intake by human was calculated using a regimen of safety and considering a consumption rate of 110 g of rice per day and an average body weight of 70 kg.
The total daily intake of As (TDI-iAs) for adults (70 kg body weight and 110 g rice consumption) was in the range of WHO recommended provisional tolerable daily intake value. Since the source of arsenic in Meydavoud is a natural source, thus, comprehensive studies are recommended on its water resources. Additionally, a solution should be found to prevent probable health effects on the residents.

Chemical pesticides are considered a vital component of farming and play a substantial role in maintaining high agricultural productivity. Concerns regarding the health and environmental effects of the pesticides have been increased in recent years. Therefore, this research aimed to assess farmers’ awareness about the positive and negative impacts of pesticides and their health risk on human.
A survey study was carried out between two groups of farmers including chemical pesticide users (n= 126) and biological pesticide users (n = 98). The users were randomly selected from 20 villages. The studied villages were selected from two sub-districts by cluster sampling method. An expert-verified questionnaire that its design and contents were assessed by local professionals was used in this research. The reliability of the questionnaire was confirmed based on the calculated Cronbach Alpha Coefficient for two constructs of awareness: positive (0.75) and negative (0.83) impacts of pesticides.
Results indicated that the farmers using biological control were well aware of the harmful impacts of pesticide and hence they used less pesticides than the chemical pesticide users. Although the two groups of the farmers highlighted the health impacts of chemical pesticides such as human and animal health threat, and pollution of surface and underground water, the users of biological control methods had more concerns in this regards. Most of the respondents stated that the pesticides caused serious health problems such as exhaustion, sweating, cough and headache, dizziness, skin inflammation and irritation, nausea and vomiting.
Even though the farmers were well aware of the impacts of pesticides use, they have less often used personal protective equipment. In order to promote farmers’ awareness of pesticide impacts, more efforts are needed to strengthen training programs and facilitate access to extension services.

The use of household water filter systems has been widely increasing in recent years because of water pollution. In water filter systems, bacterial biofilm forms on the surface of the membranes, thereby increasing the possibility of transferring antibiotic resistance among bacteria and allowing their entry into the human body. This study analyzed the types of bacteria that grow in the membranes of water filter systems and their antibiotic resistance.
For this study, samples were collected from 80 membranes of household water filter systems. Bacteria grown on these membranes were identified using biochemical and molecular methods. Resistance against antibiotics including penicillin, tetracycline, erythromycin, gentamycin, cephalexin, and trimethoprim-sulfamethoxazole was evaluated by disk diffusion method.
The detected bacteria included Pseudomonas, Rhodococcus, Bacillus, Sphingomonas, Zymomonas, Aeromonas, Klebsiella, Citrobacter, Drexia and Achromobacter. Majority of the isolates were identified as Pseudomonas aeruginosa. The antibiogram test showed that most of these bacteria exhibited multi-drug resistance (MDR). Maximum resistance was observed toward cephalexin and the least resistance was toward gentamicin.
The results revealed that membranes of household water filter systems were suitable environments for the growth of bacteria. In these conditions, MDR bacteria presumably could transfer antibiotic resistance genes to bacteria and microflora of the human body through water. Therefore, membranes should be designed in such a manner that not only they can remove the bacteria from water but also kill them.

Improper and incorrect implementation of sewage collection networks can cause environmental and health problems. It also causes dissatisfaction in urban residents. The purpose of this study was to design a questionnaire for evaluating satisfaction level of urban residents from sewage collection network. Face validity index, content validity ratio and Cronbach-coefficient were used to evaluate validity and internal consistency. The evaluated indexes were assessed in acceptable levels. The designed tool that was included 25 variables can be used to assess satisfaction level by researchers and wastewater companies.