فصلنامه محیط شناسی
سال چهل و هفتم شماره 4 (پیاپی 100، زمستان 1400)

Eliminating or deactivating the microbial pathogens in wastewater treatment plants effluent has been of particular interest to experts in order to reach the standard quality required. In the meantime, it seems obvious – due to a lack of water resources – that reusing the treated wastewater is a necessity, along with employing and developing modern, efficient solutions. In this regard, the disinfected effluent of wastewater treatment plants has raised interest in various applications containing agriculture, green space irrigation, aquifer feeding, industry, and other municipal activities. In the recent couple of decades, it can be seen that an ever-increasing attention has been paid to the use of ultraviolet (UV) radiation as an efficient method in wastewater treatment plants. However, the results of investigations and existing experiences indicate the negative impact of parameters such as turbidity, hardness, and suspended solids in wastewater on account of the diffusion of radiant energy, as well as obstructing the influence of direct radiation on microorganisms and, in turn, the performance of the UV radiation method in a disinfection process; thus, the application of modern, efficient technologies is requisite for the performance improvement of this process under different operating conditions. Due to their capability of removing toxic, resistant and non-biodegradable compounds, Advanced Oxidation Processes (AOPs) may be adopted as a suitable approach to reach the abovementioned goal. The ultraviolet radiation in conjunction with the effective radicals is considered efficient UV-based AOPs in urban wastewater treatment plants. Not only do these methods lead to reducing the probability of forming toxic and hazardous by-products, they also produce radicals that are highly reactive and react with organic compounds in a non-selective manner. AOPs can eliminate a vast variety of biological and chemical substances, as well as significantly decrease organic and inorganic pollutants by producing highly reactive free radicals, e.g., hydroxyls (OH˚) and sulfate radicals (SO4-˚). Suitable for deactivating microorganisms, these radicals decompose an extensive spectrum of resistant compounds as well. Hydroxyl-based advanced oxidation processes (HR-AOPs) have been comprehensively studied. It should be noted that the sulfate radical has higher reactivity and oxidation potential compared to the oxidizing agent of the hydroxyl radical. As a substitute for HR-AOPs, Sulfate-based Advanced Oxidation Processes (SR-AOPs) have been the focus of many researchers in recent years. This process encompasses the use of chemical oxidants such as Peroxymonosulfate (PMS), which is environmentally friendly and easily activated. The research results in recent years unanimously reveal the high efficiency of AOPs in substantial eliminations of the microbial community within the specimens tested. In the current research, the efficacy of a UV/PMS AOP, which is able to produce both sulfate and hydroxyl radicals, was investigated so as to remove the total amount of coliforms from the effluent of municipal wastewater treatment plants. In order to identify the relative advantages of this method, the obtained results were compared to those of persulfate-UV, hydrogen peroxide-UV, and UV alone methods. In addition, the effect of removing the parameters related to the quality characteristics of wastewater treatment plant’s effluent, comprising turbidity, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total nitrogen (TN), electrical conductivity (EC), total dissolved solids (TDS) and total suspended solids (TSS), was investigated under optimal operating conditions of laboratory reactors.

In this work, the treated wastewater effluent samples were collected daily near the endpoint before chlorination from an activated sludge municipal WWTP located in northeast Tehran. All the experiments were performed by a 250-cc cylindrical reactor and a UV-C lamp model UV-6W. To measure the effluent's quality parameter, we used methods from the standard methods for the examination of wastewater.

In this section, the processes of UV/PMS, UV/PS, UV/H2O2, and UV alone have been investigated on the removal of the total coliform, the results achieved as Figures 1 to 3. It was determined that increasing the production of hydroxyl and sulfate radicals during the experiments leads to an increase in the removal of total coliform. We have evaluated the optimum operational conditions for each process. In this way, 400 MPN in 100 ml was considered the allowable limit for the total coliforms to successfully disinfection according to the wastewater reuse standards for agriculture purposes. Regarding the importance of reducing the qualitative parameters of effluent, in this study, the most important parameters such as COD, BOD5, TSS, TDS, TN, TP, EC, and turbidity have been studied under optimum operational conditions of each disinfection method.In comparison, the UV-radiation alone showed the limited capability to achieve coliforms reduction requirements. As shown in Figure 1, the hydroxyl and sulfate radicals are both produced. The highest removal efficiency is by a PMS dosage of 0.09 mmol/L in a reaction time of 30 min. It should be noted, that the optimum operational conditions for the reactor to achieve the allowable limit of maximum 400 coliforms in 100 ml in a PMS dosage of 0.06 mmol/L, can be obtained by achieving log (MPN) = 2.45 (e.g., 285 MPN/100ml) in a reaction time of 20 minutes, whereas in UV/PS and UV/H2O2 the optimum operating conditions were in the dosage of 3 and 0.35 mmol/L at the time of 30 and 25 minutes, respectively. Therefore, The UV/PMS process showed the best capability to achieve coliforms reduction requirements and efficient disinfection of wastewater treatment plants effluent. As the results are shown in Table 1, the UV/PMS is the most efficient method to earn the best reduction of effluents' quality parameters. In comparison between these four processes under the optimum operational conditions, these results are achievable that the UV/PMS process had a considerable amount in the removal of turbidity and TSS. Also, it showed an appropriate efficiency in other parameters like COD and BOD5. But this method is still incapable of removing existing TN and TP concentrations.

Wastewater treatment processes with the aim of reuse and reclamation have been investigated and improved during the last decades. Also, efficient disinfection of wastewater effluent before discharge is counted as the essential requirement of reuse. In this regard, employing novel disinfection processes is vital and followed by researchers. In this study, a new approach for improving the UV-based disinfection process for wastewater effluent was investigated. The peroxymonosulfate-ultraviolet was considered as the primary method, and because the obtained results indicate the capability of this method, it was compared with persulfate-ultraviolet, hydrogen peroxide-ultraviolet and conventional UV-radiation methods. In terms of disinfection process improvement, the results demonstrate that employing the peroxymonosulfate-ultraviolet process is suitable for achieving a more reliable solution accordingly. It was also found that this method has the ability to effectively reduce the effluent's quality parameters, in addition to disinfection. It should be noted that using the peroxymonosulfate-ultraviolet method in wastewater treatment plants requires complementary studies regarding possible by-products of the process in a semi-industrial scale which are recommended to be considered in future research.

The idea of ecosystem health assessment (EHA) was introduced in environmental management in the late 1980s. In the discussion of health assessment, indicators are raised. Indicators provide a better picture of the environment Ecological indicators are committees that are closely related to the complex characteristics of the ecosystem. But these indicators are often not directly measurable. Measuring these indicators is used to simplify and evaluate various aspects of ecosystem performance. Examples of these indicators are: Vegetation density index, fold index, continuity index, Euclidean distance or distance from the nearest neighbor, environment to area ratio and spot area. The aim is to prepare a health map of the study area. In this process, after detecting changes, the thresholds of health, confusion, and disorder are determined. And health disruptors are identified. At the end, health diagnosis instructions are provided. The main question of the research is whether the health of the land has changed in the desired period of time?

The study area in this study is sub-basins of Qarahsoo, Nekarood and Gorganrood watersheds including Gorgan, Kordkuy and Bandar Gaz counties. The health utility map was obtained using the weighted linear combination (WLC) method. Thus, the health maps of 1984, 2000 and 2018 were prepared. By comparing the three maps, health changes in the study period were examined. In these layers, more desirability indicates a higher degree of power and less desirability indicates a lower degree of power for the health of the landscape. The number zero indicates the worst state of health and the number 255 indicates the best state of health in this study. In the next step, the health threshold is determined and also the health disruptors (such as human development and diseases) that are available and changeable are identified.

At this stage, land health maps have been prepared using quantitative indicators it is presented as a map. Using the health maps obtained from the previous stage and the resulting change map, the health changes of the landscape were compared statistically and visually. At this stage, the health map changes of 1984 and 2018 were prepared and classified. Areas that were unchanged from the base or had a slight change their health condition was considered excellent. Areas with low, medium, and high variation were considered good, moderate, and poor in health, respectively. In this section, changes in the landscape of the land from 1984 to 2018 were examined. From the point of view of the criteria studied in this research, in this 32-year period, the least changes and consequently the best state of health are related to 1984. Therefore, the 1984 health map was considered as the basis and other years were measured and compared accordingly. Changes in the health map of 1984, 2000 and 2018 were examined. Changes between 2000 and 2018 are negligible. Using the prepared health maps, the health changes of the land appearance between 1984 and 2018 were mapped. In the resulting change map, which was considered in the range of 0 to 255, Trial and error showed that up to 130, the changes in the study area are insignificant. Changes in the region are significant from 130 onwards. The number 130 was considered as the health threshold of the land. Therefore in addition to presenting changes in the landscape of the land, areas without change that did not cross the health threshold Changed areas that have crossed the health threshold are also shown. The development of human land uses such as urban development and roads, as well as the conversion of land uses such as forest to agriculture, rangeland and roads, runoff and erosion are introduced as factors of change. These cases may also reduce the area of forests, diseases and climate. Figure of landscape health final map of the study area presented in below: Figure of landscape health final map of the study areaLandscape health changes in the studied time periods were evaluated and compared using measures. The results in the mentioned period show the declining trend of the health of the landscape. Examination of the results shows that the uses are more uneven and the damage to the landscape has increased. Due to the increase in fragmentation index and decrease in integration and communication, the environmental situation has declined. Due to the high capability of satellite images - such as timeliness, multi-spectrum, duplication - they can be used to determine changes in the landscape in a certain period of time. Using the landform measurements, the spatial structure of the land landscape can be quantified. By establishing a relationship between the structure and performance of the landscape and a better understanding of ecological processes, it is possible to evaluate the landscape in order to plan and manage it sustainably. As a result, the use of metrics, while saving time, provides acceptable results. The measurements can be studied and extracted as quantitative indices of the environment using satellite images. The larger the area of the spots, the less damaged and intact they are. The shorter the distance between the stains, the less tampering. Therefore, closer distance is a favorable factor in the health status of the land. Maintaining the integrity and stability of the landscape based on ecological principles leads to reducing or improving the effect of human activities on biodiversity and the dynamics of local landscapes. In the discussion of detection of changes, the measurement of land use is one of the most telling measures in the study of changes in the appearance of the land. In this study, in addition to visual analysis, cross-books were used to understand where it has changed and how much. In terms of area, 2000 is not much different from 1984. In 2018, in terms of area, about 4,000 hectares were added to the development area, including the city and roads. The area of the city has tripled compared to the base year. About 26,000 hectares of forest area has been reduced. The rate of erosion has increased by about 40 hectares (increase of run off). About 9,000 hectares have been added to the area of agricultural land. About 12,000 hectares have been added to the rangeland area. The area of roads has increased by 800 hectares. The 1984 health map is in a better position than the 2000s and 2018s in terms of the indicators studied. In the map of 2000, compared to 1984, the situation of forests, pastures and agriculture has deteriorated. In the 2018 map, the situation of forests and agriculture has deteriorated, but the situation of pastures is acceptable. The number of urban spots has increased. At the city level, there are slight positive changes due to the large and concentrated spots in the city. The maps for 2000 and 2018 do not show much difference from each other. But they are a significant change from the 1984 map. Statistical analysis of the histogram shows that the 1984 curve is more homogeneous than 2000 and 2018. The 2000 and 2018 curves are closely related. Landscape changes from 1984 to 2018 were examined. From the point of view of the criteria studied in this research, 1984 is in a better health condition than other years. Therefore, it was considered as the basis and threshold of health and other years were measured and compared accordingly. In line with the findings of this study and their ecological analysis, guidelines for diagnosing the health of the landscape were presented.Keywords: Threshold, Health map, Landscape, Metrics, Landsat

Nowadays, there are various environmental problems and issues in most cities of the world, especially in developing countries. The solution to these problems requires various social, economic, and political factors. The environmental valuation in different dimensions is a way to eliminate these problems. In other words, it is necessary to valuation of goods and services using appropriate methods to express environmental role and importance and convert them into monetary values. The growth of urbanization and urban population is led to problems in the field of human habitation and land supply in most cities. Among these, land is the most basic factor of development and how to use it is one of the most important issues in urban planning. In other words, land is the main base of all citizens' activities and there is a lot of traction and demand for various activities such as providing housing, transportation, educational, commercial, medical, industrial and leisure spaces, especially in high population cities. Therefore, it is necessary to pay attention to various characteristics of the housing unit such as physical, environmental and accessibility characteristics in order to study different dimensions of housing as a heterogeneous and multidimensional commodity and to identify the affecting factors on its price. Because physical, environmental and accessibility characteristics cause differences in the tastes and preferences of heterogeneous goods consumers such as housing. There are various methods for measuring these characteristics. One of the indirect valuation methods for the estimation of willingness to pay is determination of expressed preferences using the hedonic method, in which the value of a non-market commodity is obtained by analyzing its influence on another commodity such as housing. Therefore, the present study was conducted to investigate the effect of green space on the price of surrounding houses using hedonic valuation method.

This study took place in Hafte-Tir park, Yazd city, Iran. Hafte-Tir park with approximately 5.5-ha area has been constructed in 31°51'28" to 31°51'35" latitude and 54°22'56" to 54°23'01" longitude. This park is one of the most thriving green spaces in Yazd province. This study is a kind of survey-analytical research and is also a field study in terms of data collection. The statistical community of this study is households that live in district 4 of Yazd city, in which Hafte-Tir park is located. In the study, the hedonic valuation method was used to evaluate the effect of Hafte-Tir park on the price of surrounding houses. In this regard, 15 factors including physical, environmental, and accessibility variables have been considered. Statistics and information were collected by a questionnaire through face-to-face interviews with owners of residential units and in this regard, 80 questionnaires were collected. In the hedonic method, it is assumed that the price reflects the willingness of its residents to pay for the facilities needed inside and outside of housing (physical and environmental factors). In other words, it is assumed that the difference in property prices is due to differences in housing characteristics. Therefore, the price of housing indicates the maximum amount of money that people are willing to pay to obtain a better quality of the environment, a certain amount of building facilities, as well as access to urban facilities and services. In this study, it is not possible to use a completely logarithmic form of the demand function, because of the fact that some variables are qualitative and their logarithm can not be calculated. Therefore, linear and linear-logarithmic (semi-logarithmic) shapes have been chosen to estimate the hedonic housing price function. Then, in order to analyze the data, the ordinary least squares (OLS) method and EViews software have been used. In fact, the ordinary least squares method is the simplest and most common method to estimate linear regression models. The criterion of the ordinary least squares method is that coefficients should be estimated in a manner that the residual sum of squares (RSS) is minimized.

The estimation results of the hedonic price function for residential units in Yazd city using the ordinary least squares (OLS) method showed that there is a significant relationship between the total price of housing unit and five explanatory variables including land price per m2, infrastructure, parking, distance to the main street, and distance to Hafte-Tir park (P <0.05). Between the studied variables, the variable of land price per m2 has the most influence on the dependent variable (total housing price) and its effect is positive. By one percent change in land prices, the total price will change 0.95 percent. As expected, the variables of infrastructure level had a significant positive effect on housing prices (with a coefficient of 0.89). Indeed, by one percent change in infrastructure, the total land price will change by 0.89 percent. On the other hand, the variables of parking and distance to the main street have a significant negative effect on housing price. In the absence of parking and by one meter distance to the main street, the total housing price will be reduced by 0.26 and 0.19 percent, respectively. So, it can be said that houses that are closer to the main street have higher prices due to their proximity to sales and service centers. Also, distance to Hafte-Tir park significantly affects the price of residential units (with a coefficient of 0.15). In other words, increasing one meter in the distance to park is caused increasing approximately 15 percent in housing price. Also in this study, the adjusted coefficient of determination ( ), which shows the explanatory power of the model by existing variables, indicates that 86 percent of the price changes of residential units are explained by the variables in the model.

Sample type and difference in the significance of variables are the points that make this study different from other studies. The results of the study indicate that the hedonic method is one of the methods that make a relationship between a market product such as housing and park quality by considering the effecting factors of the dependent variable. On the other hand, there are other factors than the used variables in this study that are involved in determining housing prices. Perhaps the most important of these factors are the policies and actions of national and local governments and the macroeconomic structure of the country, which are constantly causing fluctuations in housing prices.

Safety climate, which is defined as employees' perception of the organization's policies and practices regarding safety has focused on safety in organizational knowledge. Over the past few decades, much research has been done on defining, conceptualizing and exploiting the safety climate. Studies have consistently shown that safe places are those that have a positive safety climate. Safety climate is known as a major indicator of safety efficiency and a predictor of occupational accidents, and the evaluation and determination of the factors affecting it, can play a decisive role in effectively reducing the occurrence of accidents. Therefore, a valid and reliable assessment of the organization's safety climate is of great importance. Despite the great importance of safety climate in organizations and many researches which have been done in different countries, but no study has been done on the assessment of safety climate in slaughterhouses. Given that slaughterhouses are among the occupations that are dangerous in nature, in this study, safety climate and the factors affecting it in an industrial poultry slaughterhouse have been investigated.

The statistical population of the research included 482 employees of a poultry slaughterhouse. A researcher-made safety climate questionnaire was used, which is a combination of Vinodkumar and Nordic questionnaires with the focus on Vinodkumar questionnaire. The initial questionnaire contained 50 questions. To evaluate the validity of the questions, a panel of safety experts and the method of Lawshe were used and the questions that were vague and unfamiliar were removed. Thus, a questionnaire with 39 questions was obtained and Cronbach's alpha coefficient was used to evaluate the reliability of the questionnaire and 37 questions obtained an acceptable score (α = 0.9). As a result, the final questionnaire including 37 questions and 7 dimensions was designed on a five-point Likert scale. If the mean of the given answers is equal to or more than 3, its condition is estimated to be favorable. The first part deals with the demographic information of individuals and the second part measures the dimensions of safety climate. In this research, 214 people were randomly selected from 482 personnel using the Cochran's formula. After selecting the sample, each of the employees was given the necessary explanations about how to fill in the prepared questionnaire, the reason for conducting the research, the guarantee of their confidentiality, and the questionnaires were provided to them for completion. After one month, all completed questionnaires were collected. Descriptive and inferential statistics were used to analyze statistical data and examine the questions.

Among the measured factors, the employees 'attitude variable had the highest mean score of 4.57± 0.47 followed by the employees' participation and commitment in the field of safety with the mean score of 4.47. ± 0.59, respectively. The knowledge variable with the mean score of 4.42 ±0.53 and the variable of commitment and management performance regarding safety with the mean score of 4.30 ± 0.61 at the highest levels compared to other factors and above the mean Likert scale (3) and they are at a good level. The workplace safety variable with the mean score of 3.03 ± 0.78 has the lowest score, followed by the risk justification variable with the mean score of 3.44 ±1 and the emergency preparedness variable with the mean score of 3.73± 0.93, respectively are at the lowest levels compared to other variables and of course above the mean Likert spectrum. Therefore, it can be concluded that employees have a good attitude, participation and knowledge in the field of safety, but feel that their work environment is not very safe, sometimes due to familiarity with work, ignore safety and are not sufficiently prepared in emergencies. The total mean of safety climate of the study population is 3.82± 0.83. Since It is higher than mean of the Likert spectrum (3), safety climate of the studied organization is positive.The results of Friedman test show that mean scores of safety climate are significantly different. Mean score of the variable of employees' attitude towards safety with mean of 5.40 is the most important in the safety climate and then the variable of employee s' participation and commitment with a mean score of 5.10 is in the second place. Employees' safety knowledge and management commitment and performance regarding safety have a close mean that is 4.92 and 4.63, respectively. In addition, workplace safety variable with mean score of 1.89 has the least impact on safety climate, followed by risk justification variables with a mean score of 2.73 and emergency preparedness with a mean score of 3.32.Safety attitude is one of the most prominent factors influencing safety climate and has been extensively studied by other researchers such as Diaz-Kabrera et al, so our findings are consistent with their results. As Griffin et al have shown safety climate influences employees' participation and it helps to create a safe work environment. Therefor it matches with our findings. Safety knowledge is also one of the dimensions that some researchers have emphasized its importance on safe performance. The results of a study conducted by Fernández-Muñiz showed that management commitment to safety is an important dimension in the success of safety programs and has a significant impact on behaviors. Workplace safety variable with the lowest score indicates that more efforts should be made to increase the score in this dimension because personnel feel the slaughterhouse is weak in terms of providing security and a safe work environment. So to improve workplace safety, basic planning should be considered, and as much as possible safe equipment and working conditions be provided so that employees can perform their duties safely. The results of Phi and ANOVA analysis show that the only variable that has a significant relationship with the total mean of safety climate is workplace (p<0.05) and other demographic variables including age, education, accident history and work experience don’t have a significant relationship with safety climate (p> 0.05). These results indicate that different working conditions can be effective in understanding the safety climate of individuals. There was also a significant relationship between work experience with some dimensions of safety climate, which is consistent with the findings of some authors, such as Lane et al .This can be explained that by increasing the experience of individuals and holding safety training courses, their awareness of the safety of their work environment rises and as a result their knowledge of safety, participation and emergency preparedness grow, this in turn increases management's commitment to employee and workplace safety.

In general, it can be stated that total safety climate in the slaughterhouse is positive. Two components of employees’ attitudes and employee s’ participation towards safety have the greatest impact on the safety climate. Therefore, to strengthen employees’ participation, employees' attitudes and thus to improve safety performance, management commitment to safety need to be such that create a positive attitude in employees. The safety component of the workplace has the least impact on safety climate. Understanding the risk of accidents and not being safe in the workplace induces stress and reduces physical and mental capacity. Therefore, it is necessary to study the variables that can reduce the risk perception of employees and provide a safe workplace. Changing the management's attitude towards safety by prioritizing it over production in any situation and transmitting this attitude by setting safety regulations to its subordinate personnel can play an effective role in reducing accidents. The results of the study of the correlation showed that safety climate has no significant correlation with any of the demographic data other than job position and only work experience has a significant relationship with some dimensions of the safety climate and in general, it indicates that personal factors have very little impact on safety climate, and other factors such as organizational policies can play a more prominent role in safety climate.

One of the most critical and controversial issues regarding the pollution of water resources and agricultural products is the challenging relationship between nitrate intake and the risk of gastrointestinal cancers. During the last two centuries, human activities have fundamentally changed the global nitrogen cycle and increased the amount of nitrate in the soil. Nitrate and nitrite move quickly in the environment due to the high solubility. Nitrate in wastewater or fertilizers used to increase crop production can be accessed to surface and groundwater by rainfall or irrigation. Nitrate in the diet is absorbed into the bloodstream and enters the oral fluid through the salivary glands. Approximately 25% of nitrate in the human body enters the salivary glands after absorption in the upper gastrointestinal tract, and it is actively concentrated up to 20 times in saliva. Nitrite disrupts young vertebrates by destroying hemoglobin in the blood and forming the toxic compound methemoglobin. Nitrite also causes hypotension (reduction of arterial pressure), a precursor to the formation of carcinogenic nitrosamines. However, there is no conclusive evidence that nitrate can cause cancer without amines containing nitrosamines.Since accurate information about the amount of nitrate in drinking water sources and vegetables used in Mazandaran province is not available, this study aimed to obtain accurate and up-to-date data on nitrate concentration in drinking water and vegetables. Also, the relationship between nitrate concentration in drinking water and vegetables in areas of Mazandaran province with a high and low prevalence of gastrointestinal cancers was investigated.

In this study, two areas with high incidence and low incidence of gastrointestinal cancers (Savadkuh and Simorgh counties, respectively) were identified. Information on patients with gastrointestinal cancer was prepared between 2014-2016. Then the patients living in the studied counties were separated and coded. Nitrate concentration in 30 samples of vegetables (60 samples in total) and water was analyzed by spectrophotometry and compared with international standards.The selection of vegetable samples was made according to the prevailing consumption pattern of the people. Selected vegetables included tomatoes, lettuce, potatoes, onions, cucumbers, garlic, cress, and spinach. According to the available instructions, plant samples from each region were quickly transferred to the laboratory. Nitrate concentration was measured by the semi-micro distillation method. The relationship between nitrate concentration and the incidence of gastrointestinal cancer and the ASR index of gastrointestinal cancer were determined using SPSS (26) software for Mazandaran province.Discussion of

Statistical analysis of the data showed that nitrate concentration of all studied crops in the Savadkooh region showed a significant difference compared to the Simorgh region, except potato. In the Simorgh region, nitrate concentration in lettuce, cress, potato, and spinach was lower than the maximum limit, while other vegetables were significantly higher than the standard. The data showed that in Savadkuh and Simorgh regions, the highest nitrate concentration was observed in garlic and the lowest in onion. According to the data, except for potatoes, all other vegetables in the Savadkooh region were significantly higher than the Simorgh region (p <0.01). The average concentration of nitrate in the drinking water of Savadkooh and Simorgh counties was significantly lower than the standards presented in the literature.The effect of nitrate concentration variables (in the regression model presented) in tomatoes, potato and cucumber, and drinking water was more than the allowable error (0.05). Therefore, changes in the nitrate concentration of these products and the amount of nitrate in drinking water will not significantly affect changing the dependent variable (the incidence of cancer). On the other hand, the significance level of the t-test for the effect of nitrate concentration variables in spinach, garlic, cress, and onion was less than the allowable error (0.01). Therefore, changes in the amount of nitrate in these variables significantly affect changes in the dependent variable. Based on the coefficients related to β, the most effect on the changes of the dependent variable will be the change in the amount of nitrate in spinach and garlic with a coefficient of β of 0.372 and 0.367, respectively. The amount of nitrate in the variables of cress and onion are of the following ranks. Comparison of residual nitrate levels in vegetables in Savadkuh and Simorgh showed that nitrate levels in Simorgh city were lower than Savadkuh, and nitrate concentration in four vegetables i.e. lettuce, cress, onion, and spinach, was less than the maximum limit. However, other products far exceeded the maximum limit. According to the researchers of the Razi University of Kermanshah, the concentration of nitrate in all cases under investigation in Kermanshah was exceeded by the National Standard Institute of Iran. The highest and lowest nitrate concentrations were observed in the Savadkuh region with an average of 3398 and 71 mg/kg in garlic and onion crops, respectively, and in the Simorgh region with an average of 2259 and 38 mg/kg in garlic and potato as well. The common denominator between the two regions is the lowest nitrate concentration observed in the onion crop. Significant differences between the two counties in terms of nitrate concentration in the studied products, except potato, can be examined from various aspects. It seems that the management of fertilizer consumption, especially nitrogen fertilizers in the Simorgh region, has been done better. The result has been shown by reducing nitrate accumulation in agricultural products of the region. Nitrogen in chemical and organic fertilizers is converted to nitrate after use in soil by soil bacteria such as Nitrosomonas and Nitrobacter. Nitrate absorbed in the root is reduced and converted to ammonium compounds and transferred through the vascular system to different parts of the plant, and used in physiological processes of the plant. Suppose the amount of soil nitrate increases for any reason, including excessive consumption of nitrogen fertilizers, and the plant does not have the necessary ability to reduce it. This compound enters the plant organs through the mass transfer mechanism and the vascular system and accumulates there.It has been found that there is a direct relationship between the concentration of nitrate in the environment and the amount of nitrate accumulation in agricultural and horticultural products, so that the most important environmental factor affecting the accumulation of nitrate in the product is the amount of available nitrate ions. In addition, harvest time (morning or evening) is also an essential factor in the amount of nitrate output through the harvested product. Receiving light energy during the day increases the plant's photosynthesis, and the production of more assimilates and increases the activity of the enzyme nitrate reductase in the plant. The average nitrate concentration in drinking water was 10.4 mg/L in Savadkuh and 15.8 mg/L in Simorgh. Fortunately, this concentration is lower than the standard defined for drinking water (50 mg/L) in both areas.

Although the concentration of nitrate in the drinking water of Savadkuh county is significantly higher than Simorgh one, the concentration of nitrate in the drinking water of both counties is below the standard limit. Therefore, there is probably no significant relationship between the prevalence of gastrointestinal cancers and nitrate concentration in drinking water sources in these areas.Nitrate concentration in vegetables consumed by patients with gastrointestinal cancers in the Savadkuh region was significantly higher than the Simorgh region and, to some extent, maximum contaminant level. The results showed that the consumption of spinach, garlic, cress, and onion had played an influential role in increasing the incidence of gastrointestinal cancers. Therefore, management practices in agriculture, especially changes in the consumption pattern of nitrogen fertilizers, are inevitable to reduce the accumulation of nitrate in vegetables. It is strongly recommended that the vegetables be harvested in the afternoon to reduce nitrate accumulation in the plant tissues. It is suggested that new strategies to reduce nitrate accumulation in food, especially vegetables, be studied to reduce the incidence of gastrointestinal cancers in this province.

Investigation of Contamination Potential in the area of Ahar Mazareh Copper Mine and Determination of their Origin.IntroductionInvestigating the quality of water resources in an area is one of the most fundamental issues in the study of contamination. The term “trace elements” generally refers to elements that are present in the environment in small concentrations and can be hazardous at concentrations above the permitted standard of drinking. The origin of these elements can be geogenic or anthropogenic. The geogenic origin of these elements is the earth's crust, and the anthropogenic origin can also be due to industrial, agricultural, and mining activities. One of the strategic tasks in the field of water resources is to provide chemical information in a way that it can be visually reconstructed. Mazraeh mine is one of the copper mines in Iran that uses a lot of water daily to concentrate copper through flotation, which along with other contaminates is directed to the tailings dam, Therefore, it is necessary to study the affected factors to the hydrochemical evolution and quality of surface and groundwater resources and to investigate the relationship between elements and contaminates and its impact on the quality of water resources and most importantly the origin of these elements and their relationship with mining and tailings dams. In this study, Hydrochemical study of water resources in the study area has been done by plotting methods such as Piper and Stiff diagrams. Multivariate statistical methods such as factor and cluster analysis were used to evaluate the origin of the trace elements.Materials and MethodsMazraeh copper mine is located 5 km from Mazraeh, and 120 km from Tabriz. It is located in the north of East Azarbaijan. Geologically, the study area is part of the Alborz-Azarbaijan structural unit. The geological map of the study area shows that the oldest geological units in the study area belong to the Cretaceous. Mazraeh copper mine reserves are of the iron and copper skarn index type. In general, in this study, on average, about 16 water samples were collected monthly from surface and groundwater resources in the area of the Mazraeh copper mine; The samples include 8 water samples from piezometers in the area, 1 sample from tailings dam, 1 sample from overflow of the tailings dam, 1 sample from water well of the village near the mine, and 5 samples from springs. Discussion of ResultsThe amount of electrical conductivity also varies between 254 and 1774 μS / cm. The amount of the concentrations of the major cations and anions in terms of the median are "potassium ConclusionsBased on the results, the Piper and Stiff diagrams plotted for water, the water type was mainly divided into two groups of sulfate and bicarbonate; the resource of water in the area corresponds to the geological formations of the area. The results of chemical analysis of about 290 water samples showed that some trace elements such as cadmium, lead, and cobalt have more concentrations than the standard of drinking water. The results of factor analysis showed that 4-factor groups were effective in the quality of water resources in the Mazraeh copper mine area. The second and the third factors were geogenic and the first and the fourth factors were affected by both geogenic and anthropogenic factors. The majority of trace elements in water resources are affected by the impact of formations and water-rock interaction. In the clustering method, amount of EC, sulfate, and calcium in the first cluster is more than in the second one, which indicates the effect of dissolution of sulfide minerals such as pyrite and chalcopyrite in the area. The amount of zinc and iron in the second cluster is more than the first cluster.