نشریه محیط زیست طبیعی
سال هفتاد و دوم شماره 3 (پاییز 1398)

Given the importance of groundwater resources and the water shortage crisis in Iran, a significant attention should be paid to these resources. One of regarding challenges is the resource pollution; therefore the vulnerable resources should be revealed based on suitable assessments to eliminate pollutions by the necessary actions. In the most cases, the groundwater pollution can be detected after the drinking water wells were polluted. Detection of vulnerable zones of an aquifer can be used for the groundwater pollution preventive actions. Different vulnerability assessment methods have been presented which one of the proper and well-known methods of overlaying indicator named SINTACS has been used in this research. The study aims assessing the qualitative vulnerability of Birjand plain aquifer, using SINTACS model for a statistical period of 2016-2017. Based on the results of this assessment, the SINTACS vulnerability zoning map indicates that 12.81 percent of the zone space has a vulnerability of medium to high level, 80.47 percent of the space has a high vulnerability level and 6.71 percent of the space has a very high vulnerability level. For the SINTACS model verification, the relation between vulnerability and Nitrate density values of 21 groundwater samples have been examined. The gained correlation coefficient between vulnerability index of SINTACS and Nitrate density was 71 which shows suitable correlation of this model with Nitrate density as groundwater pollution index.

The drought effect that means water shortages due to drought events, is that one percent of the water access limitations, ceteris paribus, how many percent reduces the economic growth. In the last decades environmental economists have been answering this question that is whether there is a level of consumption and discharge of water resources that reverses the positive impact of water on production. To this end, using data from 30 provinces during the period 1383-1396 and application of Spatial Aotu Regressive General Momentums Model Dynamic Panel Data A new interpretation of the drought and thresholds effect for the extraction of groundwater resources on the real GDP was presented. The results showed that groundwater resources at the surface and squared have 556/7311 and -0/0065 coefficients. The threshold was estimated at 42/825 billion cubic meters per year. Extracting over this threshold has a negative environmental, economic, social and political impact that leads to a reduction of real GDP in the provinces of Iran. Thus, the drought effect on the provinces of Iran is not rejected. Human footprints are also visible in underground water supplies. Also, the spatial lagged variable has a coefficient of 0/1064 which indicates that the discharge of basin whose geographic location is from an environmental dimension independent of political divisions has spatial effects on the real GDP of adjacent provinces. It is suggested that the authorized and unauthorized water rent is controlled with using temporary water ownership instead of permanent ownership. The demand side is controlled and the economic production of water is strengthened using water market tools. So underground water resources have been reduce until reach below the threshold to zeroing the negative consequences of resource extraction.

Surfactants are one of the most important pollutants of surface water and underground water resources, and create potential health risks for humans and environment. The purpose of present study was to synthesize the MGNCs to be used for the removal of sodium dodecyl benzenesulfonate (SDBS) from aqueous solutions. First, graphene was synthesized through pyrolysis of orange peel as carbon precursor and KOH as an activating agent. The magnetic adsorbent nanocomposite was prepared through the solvothermal method using ferric chloride hexahydrate. The absorbent characteristics were analyzed using Fourier transformed infrared (FT-IR), vibrating sample magnetometer (VSM), Atomic force microscope (AFM), scanning electron microscopy (SEM) and Raman spectrometer techniques. The effects of the adsorbent amount, pH, the initial concentration of SDBS, and contact time were investigated for removal of SDBS. The adsorption isotherms were interpreted using Langmuir and Freundlich models and the kinetic data of adsorption process was also evaluated using pseudo-first-order and pseudo-second-order kinetic models. Based on the findings of the study, the absorbent dose of 20 mg, pH 3 and the contact time of 60 min were found to be the optimal conditions for the removal of SDBS. The equilibrium isotherm data fitted well with the Langmuir model (R2 = 0.9989) and the pseudo-second-order kinetic model was found to explain the adsorption kinetics more effectively (R2 = 0.9992). The maximum adsorption capacity of SDBS onto magnetic graphene nanocomposite was attained to be about 276 mg/g. Desorption experiments of ethanol and methanol from MGNCs were performed. The percentage adsorption recoveries of ethanol and methanol were 74 and 76%, respectively. The results showed that the as-synthesized MGNCs has an efficient and cheap adsorbent for removal of SDBS because of its high adsorption capability, high porosity, and large surface area and has the advantage of easy and rapid separation from the aqueous solution via external magnetic field.

Today, the issues mentioned in the international community are environmental issues and the warming of the air. One of the things that has a direct impact is carbon dioxide emissions. Different countries have been working to reduce environmental emissions in the past years by joining environmental protocols. It has to be explained that various studies have shown that several factors influence the amount of carbon dioxide emissions in the world, and if any of these factors are controlled, it will reduce the release of this gas in the environment. Therefore, considering the importance of carbon dioxide emissions, this study examined the effects of economic growth, degree of economy openness, energy consumption and rural population in selected OECD countries. The method used in this research is panel data with using of generalized least squares method. The results showed that energy consumption has a significant positive effect and rural population has a negative significant effect on carbon dioxide emissions in these countries during the period 2014-1990.

Groundwater is the most important source of potable water in the most of the cities and villages of Iran. Nitrate and phosphate are the greatest current groundwater pollutants that threaten the health of the people in Iran. This research was done with the aim of assessing the effect of land use on the quality of potable water. To this aim, 132 water samples from 132 wells used for drinking purposes in different locations of the province were prepared, and nitrate and phosphate concentrations in samples were measured with a spectrophotometer. The results showed nitrate concentrations in 92.42% of the samples were below the permitted limit, while 7.58% of the samples were higher than standard. Phosphate concentration in 100% of the samples was lower than both the global and Iranian standards. Also, there was significant correlation between nitrate and phosphate concentrations (r = 0.29). According to the obtained results, nitrate concentrations in residential areas were significantly different from those in rangeland, forest and garden land uses (p <0.05). Phosphate concentration in residential areas, agriculture, rangeland and garden land had significant differences with those in forest land use (p <0.05). Now, water quality with regard to nitrate concentration in most parts of the province and phosphate concentration in all parts of province were in compliance with standards, but nitrate concentration was 10 points higher than the permitted level. Therefore, monitoring, purification, wastewater generation and lower consumption of nitrate fertilizer should be considered.

In this study, the carbonaceous adsorbents were prepared from the waste of crude oil storage tanks using with steam at various temperatures. The optimum adsorbent was selected for further experiments after characterization of specific surface area and textural properties. Batch experiments of nickel adsorption were performed with initial concentration of 25-200 mg/L, pH 2-8, contact time 5-240 min and absorbent dose of 1-5 g/L. The results showed that among the three synthesized absorbents, the obtained adsorbent at 900 ˚C showed the higher surface and best structural properties with a specific surface area of 422 m2/g and a total pore volume of 0.55 m3/g. The results of nickel adsorption showed that the removal efficiency increases with increasing the contact time and absorbent dose. Maximum nickel adsorption efficiency was obtained at pH 5, contact time of 60 min and absorbance dose of 2 g/L. In addition, it was observed that the adsorption data follow the Langmuir and Freundlich isotherms. The results of fitting the kinetic models for all adsorbents indicate that the adsorption process follow the pseudo second order kinetic model. Base on the results of this study, it can be stated that the activated carbon produced from oily sludge can be considered as an efficient and cost effective adsorbent for treatment of industrial wastewater.

Wastewater is one of the environmental pollution that should be collected, treated and, if possible, recycled back into the water cycle. Antibiotics are hazardous environmental pollutants and have been named as emergency contaminants due to their unique physical and chemical structures. Advanced oxidation processes are a powerful method for the degradation of contaminated water containing inorganic pollutions. Its main mechanism is based on the production of free radicals that have been very effective in eliminating organic materials. In this study, the effect of solar photocatalyst in order to remove amoxicillin from contaminated water by photocatalyst have been investigated and the effects of pollutant concentrations, photocatalyst concentration and initial pH have been investigated. The sun's ultraviolet energy is used to active photocatalyst. The reactor used in this study has a combined parabolic collectors that have the best performance. Among the parameters studied, pH, photocatalytic concentration, and pollutant concentrations had the highest effect on degradation efficiency, respectively. According to this study, amoxicillin degradation in alkaline condition is well done. In the same conditions, with an increase in pH from 3.5 to 9.5, the degradation efficiency increased to 83.51 percent. High efficiency in alkaline pH due to the higher hydroxylation of amoxicillin and the instability of its beta-lactam ring, and the production of more radical hydroxyl with respect to the physical and chemical structure of the pollutant and photocatalyst. According to the results, solar photocatalyst is a suitable method for the removal of amoxicillin from wastewater.

Cotton has economic and commercial importance, due to the various uses in today's world. It is also one of the most important oily plants in the world, and its cultivation is increasing in countrys. In recent years the government has special attention, considering that this product is the raw material of textile industry; therefore, the evaluation of this product is a very important factor and has an impact on increasing its production and performance without the need for additional costs. In the present study, technical, allocation, economic, and technical measures were performed with two standard and combined methods, at two fixed and variable levels, in order to determine the water use efficiency and its environmental performance in the producing provinces of this product. The statistical data of this study were extracted from the Agricultural Jihad in the years 2015-2014. The average economic efficiency, variable in relation to scale in both standard and environmental methods is respectively 0.81 and 0.78% respectively. In this study, after solving the institutionalization overlay model, the results were compared to the standard scale for comparing both standard and environmental methods at constant and constant levels. Based on these results, the provinces that are well-known efficient in the standard method are also relatively efficient by the specific environmental method. But for non-efficient provinces, the estimated value of the special compilation method is lower than the standard values. It is advisable to help raise the productivity of cotton farmers through their participation in extension classes, the improvement of irrigation practices and the use of green water (sewage treatment).

Fire is considered as one of the main causes of disruption and change in natural ecosystems. Identifying the effective factors in the occurrence of a fire and providing a spatial pattern of its risk is one of the basic tools for achieving fire control. The statistics showed that 1124 incidents of fire caused to burning of 7364 hectares of forests and rangelands in Kurdistan province, between 2006 and 2015. Therefore, in this research, a fire risk map was developed in natural areas in Kurdistan province using statistical index method (SI) and Geographic Information System (GIS). In this study, in order to prepare a fire hazard map, six parameters including three natural variables: slope percentage, aspect, elevation and three human variables, distance from the village, distance from the road and distance from the agricultural land were used. From all of 1124 fire cases, 70% of the data (787 cases) were used for modeling and 30% (337 cases) were used for model verification. The results showed that about 50% of the area of Kurdistan province (14400 km2) is in high and very high fire hazard classes. Also, findings showed the high accuracy of the statistical index method in identifying areas with a fire hazard with a precision of 93.5% (315 out of 337 cases of fire).