تأثیر آبیاری با فاضلاب تصفیه نشده شهری بر تجمع فلزات سنگین در خاک سطحی و زیرسطحی
محورهای موضوعی : آلودگی های محیط زیست (آب، خاک و هوا)عیسی سلگی 1 , مهدی شاهوردی نیک 2 , مهدی رمضانی 3
1 - دانشیار گروه محیطزیست، دانشکده منابع طبیعی و محیطزیست، دانشگاه ملایر، ملایر، ایران. *(مسوول مکاتبات)
2 - کارشناسی ارشد محیطزیست، دانشکده محیطزیست و انرژی، دانشگاه آزاداسلامی، واحد علوم و تحقیقات تهران، تهران، ایران.
3 - استادیاردانشکده منابع طبیعی و محیطزیست، دانشگاه آزاداسلامی، واحد علوم و تحقیقات تهران.
کلید واژه: خاک, فلزات سنگین, آبیاری با فاضلاب, تغییرات عمقی,
چکیده مقاله :
زمینه و هدف: به دلیل کمبود آب شیرین برای آبیاری، فاضلاب به عنوان یک مکمل مهم و منبع آب جایگزین در دهه های اخیر در آبیاری زمین های کشاورزی های استفاده شده است. آبیاریمزارع با فاضلاب سبب آلودگی فلزات سنگین در خاک، محصولات کشاورزی و آب های زیرزمینی می شود، در نتیجه تهدیدی برای سلامت انسان و امنیت غذایی است. هـدف از انجـام ایـن پژوهش بررسی اثر آبیاری با فاضلاب تصفیه نشده شهری بر تجمع سرب، کادمیوم مس و روی در خاک سطحی و زیرسطحی و ویژگی های خاک سطحی بود. روش بررسی :در تحقیق حاضر به منظور برداشت نمونه های خاک سطحی (0-20 سانتی متر) و زیر سطحی (20-40 سانتی متر) از اراضی کشاورزی جنوب شهر بروجرد، 13 مزرعه آبیاری شده با فاضلاب تصفیه نشده شهری و 7 مزرعه آبیاری شده با آب چاه که بافت خاک مشابهی داشتند انتخاب شدند. نمونه های خاک برای اندازه گیری سرب، کادمیوم، مس ، روی،pH ، EC و مواد آلی خاک طبق روش های استاندارد آنالیز شدند. یافته ها: نتایج بدست آمده نشان داد که میانگین غلظت همه فلزات سنگین در خاک سطحی (بجز مس) و زیرسطحی آبیاری شده با فاضلاب تصفیه نشده شهری در مقایسه با خاک آبیاری شده با آب چاه بیشتر بود. روند تغییرات عمقی فلزات در خاک آبیاری شده به این شکل بود: 1-با فاضلاب شهری: سرب و مس خاک زیرسطحی>خاک سطحی ؛ کادمیوم و روی خاک سطحی>خاک زیرسطحی و 2-با آب چاه: سرب و مس خاک سطحی>خاک زیرسطحی ؛ کادمیوم و روی خاک زیرسطحی > خاک سطحی. بحث و نتیجه گیری: به نظر می رسد بافت سبک خاک سبب انتقال این فلزات به لایه های پایین خاک شده است. به طور کلی، غلظت سرب، مس و روی پایین تر از استاندار FAO/WHO و کادمیوم بالاتر از آن بود. بنابراین، به منظور حصول اطمینان از ایمنی غذایی و استفاده از فاضلاب برای آبیاری، نظارت مستمر و کنترل آلودگی مورد نیاز است. در ضمن چنانچه تصفیه فاضلاب به طور مناسب انجام شود، تجمع فلزات سنگین در خاک و محصولات کشاورزی کمتر اتفاق خواهد افتاد.
Background and Objective: Due to the shortage of freshwater for irrigation, wastewater has been used in agricultural irrigation as an important supplement and alternative water resources in recent decades. Irrigation of fields with wastewater can cause potential contamination with heavy metals to soil crops and groundwater, therefore pose a threat to human health and food safety. The aim of this research was to evaluate the effect of irrigation with untreated municipal wastewater on the accumulation of cadmium lead (Pb), (Cd), copper (Cu) and Zinc (Zn) in topsoil and subsoil and top soil properties. Method: In the present study in order to collection of topsoil (0-20 cm) and subsoil (0-40 cm) samples from south of the Borujerd city, 13 fields irrigated with untreated wastewater and 7 fields irrigated with well water were selected with same soil texture. Soil samples were analyzed by the standard methods for Pb, Cd, Cu, Zn, pH, electrical conductivity (EC), organic matter (OM). Findings: Findings indicated that untreated wastewater irrigated soil contained higher concentrations of all heavy metals in topsoil (with the exception of Cu) and in subsoil, compared to well water irrigated soil. Trend of depth variations of metals in irrigated soil followed this form: 1-With wastewater: Pb and Cu in subsoil>topsoil; Cd and Zn in topsoil > subsoil and 2-With well water: Pb and Cu in topsoil > subsoil; Cd and Zn in subsoil > topsoil. Discussion and Conclusion: It seems that light soil texture has been resulted to transport of the metals to deeper soil layers. Overall, the concentrations of Pb, Cu, and Zn were lower than the FAO/WHO standards in soil, while Cd higher than this. Thus, in order to ensure food safety and use of wastewater for irrigation, continuous monitoring and pollution control is required. Besides, if treatment of wastewater is done appropriately, accumulation of heavy metals in soils and crops will occur less.
- Tóth, G., Hermann, T., Szatmári, G., Pásztor, L. 2016.Maps of heavy metals in the soils of the European Union and proposed priority areas for detailed assessment. Science of the Total Environment 565 (2016): 1054–1062.
- Liu, Y., Wang, H., Li, X., Li, J. 2015. Heavy Metal Contamination of Agricultural Soils in Taiyuan, China. Pedosphere 25(6): 901–909, 2015.
- Flores-Magdaleno, H., Mancilla-Villa, O. R., Mejía-Saenz, E, Bautista-Olivas, A.L. 2011.Heavy metals in agricultural soils and Irrigation wastewater of Mixquiahuala, Hidalgo, Mexico. African Journal of Agricultural Research 6(24): 5505-5511.
- Pourang, N., Noori, A.S. 2014. Heavy Metals Contamination in Soil, Surface Water and Groundwater of an Agricultural Area Adjacent to Tehran oil Refinery, Iran. Int. J. Environ. Res., 8(4):871-886.
- Ibrahim, A.K., Yakubu, H., Askira, M.S. 2014. Assessment of Heavy Metals Accumulated in Wastewater Irrigated Soils and Lettuce (Lactuca sativa) in Kwadon, Gombe State Nigeria. American-Eurasian J. Agric. & Environ. Sci., 14 (6): 502-508.
- Alghobar, M.A., Suresha, S. 2017. Evaluation of metal accumulation in soil and tomatoes irrigated with sewage water from Mysore city, Karnataka, India. Journal of the Saudi Society of Agricultural. 16(1) 2017: 49-59.
- 7-Meng, W., Wang, Z., Hu, Beibei, Z., Hongyuan Lic, W., Goodman, R.C. 2016. Heavy metals in soil and plants after long-term sewage irrigation at Tianjin China: A case study assessment. Agricultural Water Management 171:153–161.
- Bashir, F., Kashmiri, M.A., Shafiqa, T., Tariqa, M. 2009. Heavy metals uptake by vegetables growing in sewage irrigated soil: relationship with heavy metal fractionation in soil.Chemical Speciation and Bioavailability 21(4):199-209.
- Khan, S., Cao, Q., Zheng, Y.M. , Huang, Y.Z., Zhu, Y.G. 2008.Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China. Environmental Pollution 152: 686-692.
- Tabari, M., Salehi, A. 2012. Impact of irrigation by municipal sewage on accumulation of heavy metals in soil. Journal of Environmental Science and Technology. 13(4): 49-60 (In Persian).
- Beigi Harchegani, H., Banitalebi, G. 2013. The Effect of twenty-three years of surface irrigation with treated municipality wastewater on soil loadings, transfer to wheat and corn grains, and related health risks of some heavy metals. Journal of Water and Soil. 27(3):570-580 (In Persian).
- Christou, A., Eliadou, E., Michael, C., Hapeshi, E., Fatta-Kassinos, D. 2014 Assessment of long-term wastewater irrigation impacts on the soil geochemical properties and the bioaccumulation of heavy metals to the agricultural products. Environmental Monitoring and Assessment 186(8):4857–4870.
- Li, P., Wang, X., Allinson, G., Li, X., Xiong, X. 2009. Risk assessment of heavy metals in soil previously irrigated with industrial wastewater in Shenyang, China. Journal of Hazardous Materials 161(1): 516–521.
- Statistical yearbook of Lorestan Province. 2011. 522 pages (In Persian).
- Maleki Rad, Z., Baharvand, S., Nouryazdan, A., Amini Kia, A. 2011. Geological study of Lorestan plains and its impact on the quality and quantity of water resources using satellite data. Regional Conference on Geology of Iran Plateau. Islamic Azad University of Zarand (In Persian).
- Tabandeh, L., Taheri, M., 2016. Assessment of pollution and relationship between heavy metals Concentration in soil and leafy vegetables in Zanjan Province. Iranian Journal of Soil Research. 30(1):49-60 (In Persian).
- Kabata-pendias, A., Pendias, H., 2001. Trace elements in soils and plants. 3rd edition. CRC Press, Boca Raton, Florida, 413 pp.
- FAO/WHO. 2001. Food additives and contaminants, Joint Codex Alimentarius Commission, FAO/WHO. Food standards Programme, ALINORM 01/12A.
- Zafarzadeh, A., Mehdinejad M.H., Amani, N. 2015. Accumulation of heavy metals in agricultural soil irrigated by sewage sludge and industrial effluent (case study: Agh ghallah Industrial Estate. J Mazandaran Univ Med Sci. 25(121): 217-226 (In Persian).
- Rattan, R. K., Datta, S. P., Chhonkar, P. K., Suribabu, K., & Singh, A. K. 2005. Long-term impact of irrigation with sewage effluents on heavy metal content in soils, crops and groundwater-a case study. Agriculture, Ecosystems & Environment, 109 (3 – 4): 310 – 322.
- Xu, J., Wu, L., Chang, A. C., Zhang, Y. 2010. Impact of long- term reclaimed wastewater irrigation on agricultural soils: a preliminary assessment. Journal of Hazardous Materials, 183 (1 – 3): 780 – 786
- Mojiri, A. 2011. Effects of Municipal Wastewater on Physical and Chemical Properties of Saline Soil. J. Biol. Environ. Sci., 5(14): 71-76.
- Rusan, M, Hinnawi, S, Rousan, L. 2007. Long term effect soil and plant quality parameters. Desalination. 215: 143-152.
- Jahantigh, M .2008. Impact of Recycled Wastewater Irrigation on Soil Chemical Properties in an Arid Region. Pakistanian Journa l of Biological Sciences. 11(18): 2264-2268.
- Khai, N.M., Tuan, P.T, Vinh, C.N., Oborn, I. 2008. Effects of using wastewater as nutrien t sources on soil chemical properties in p eri- urban agricultural systems. VNU Journal of Science, Earth Sciences. 24: 87-95.
- Friedel, J.K., Langer, T., Siebe, C., Stahr, K. 2000. Effects of long-term waste water irrigation on soil organic matter, soil microbial biomass and its activities in central Mexico, Biol. Fertil. Soils 31:414–421.
- Tunc, T., Sahin, U. 2015. The changes in the physical and hydraulic properties of a loamy soil under irrigation with simplerreclaimed wastewaters. Agricultural Water Management 158:213-224.
- Gupta, N., Khan, D.K., Sandra, S.C. 2008. An assessment of heavy metal contamination in vegetables grown in wastewater-irrigated areas of Titagarh, West Bengal, India. Bull. Environ. Cont. Toxicol. 80, 115–118.
- Kumar, V., Chopra A. K., Srivastava, S. 2014. Distribution, enrichment and accumulation of heavy metals in soil and Vigna Mungo L. Hepper (Black Gram) after irrigation with distillery Wastewater. J Environ Health Sci 1(1): 1-8.
- 31-Chen, Z.F., Zhao, Y., Zhu, Y., Yang, X., Qiao, J., Tianc, Q., Zhang Q. 2009. Health risks of heavy metals in sewage-irrigated soils and edible seeds in Langfang of Hebei province, China. Journal of Science Food Agriculture, 90:314-320.
- Massaquoi, L.D., Ma, H., Liu, X.H., Han, P.Y., Zuo, S.M., Hua, Z.X., Liu, D.W. 2015. Heavy metal accumulation in soils, plants, and hair samples: an assessment of heavy metal exposure risks from the consumption of vegetables grown on soils previously irrigated with wastewater. Environ Sci Pollut Res Int. 22(23):18456-68.
- Mapanda, F., Mangwayana, E.N., Nyamangara, J., Giller, K.E., 2005. The effect of longterm irrigation using wastewater on heavy metal contents of soils under vegetables in Harare, Zimbabwe. Agric. Ecosyst. Environ. 107:151–165.
- Wali, A., Colinet, G., Ksibi, M. 2014. Speciation of Heavy Metals by Modified BCR Sequential Extraction in Soils Contaminated by Phosphogypsum in Sfax, Tunisia. Environmental Research, Engineering and Management 4(70): 14–26.
- Adeyi A., Torto, N. 2014. Profiling heavy metal distribution and contamination in soil of old power generation station in Lagos, Nigeria. 1(1): 1-10.
- Etim, A. O. Ekpo, F. E., Okeke, A. I. 2016. Assessment of Heavy Metals Concentrations in Soils and Edible Vegetables Grown in Core Crude Oil Producing Communities of Ibeno, Akwa Ibom State, Nigeria. 4(1): 1-6.
- Duan, X., Zhang, G., Rong, L., Fang, H., He, D., Feng, D. 2015. Spatial distribution and environmental factors of catchment-scale soil heavy metal contamination in the dry-hot valley of Upper Red River in southwestern China. Catena 135: 59–69.
- Bansal, R.L., Nayyar, V.K., Takkar, P.N. 1992. Accumulation and bioavailablity of Zn, Cu, Mn, and Fe in soils polluted with industrial wastewater. J. Ind. Soc. Soil. Sci. 40:796–799.
- Singh, G., Bhati, M. 2005. Growth of Dalbergia sissoo in desert regions of western India using municipal effluent and the subsequent changes in soil and plant chemistry. Bioresource Technology, 96 (9): 1019-1028.
- Rieuwerts, J. S., Thornton, I., Farago, M. E., Ashmore, M. R. 1998. Factors influencing metal bioavailability in soils: preliminary investigations for the development of a critical loads approach for metals. Chemical Speciation and Bioavailability, 10(2): 61-75(15).
- Salehi, A., Tabari, M., Mohammadi, J., Ali Arab, A. 2008. Accumulation of Ni, Cu, Zn and Pb in soil and leaf of Robinia under the influence of urban sewage. Pajouhesh and Sazandegi, 92-100.
- Ungaro, F., Ragazzi, F., Cappellin, R., Giandon, P. 2008. Arsenic concentration in the soils of the Brenta Plain (Northern Italy): Mapping the probability of exceeding contamination thresholds. Journal of Geochemical Exploration 96(2–3):117–131.
- European Union, 2002. Heavy Metals in Wastes, European Commission on Environment.http://ec.europa.eu/environment/waste/studies/pdf/heavy metalsreport.Pdf> (accessed 12.06.12)
- Luo, C., Liu, C., Wang, Y., Liu, X., Li, F., Zhang, G.G., Li, X. 2011. Heavy metal contamination in soils and vegetables near an e-waste processing site, south China. J. Hazard. Mater. 186:481–490.
12. Karimi, B., Abdi, CH., Fathi- Tilko, Z., Gavilian, H. 2016. Effect of Irrigation with Treated Urban Wastewater on Heavy Metals Accumulation and Distribution in Soil Profile under Corn and Tomato. Water Research in Agriculture30(1):89-101 (In Persian).
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- Tóth, G., Hermann, T., Szatmári, G., Pásztor, L. 2016.Maps of heavy metals in the soils of the European Union and proposed priority areas for detailed assessment. Science of the Total Environment 565 (2016): 1054–1062.
- Liu, Y., Wang, H., Li, X., Li, J. 2015. Heavy Metal Contamination of Agricultural Soils in Taiyuan, China. Pedosphere 25(6): 901–909, 2015.
- Flores-Magdaleno, H., Mancilla-Villa, O. R., Mejía-Saenz, E, Bautista-Olivas, A.L. 2011.Heavy metals in agricultural soils and Irrigation wastewater of Mixquiahuala, Hidalgo, Mexico. African Journal of Agricultural Research 6(24): 5505-5511.
- Pourang, N., Noori, A.S. 2014. Heavy Metals Contamination in Soil, Surface Water and Groundwater of an Agricultural Area Adjacent to Tehran oil Refinery, Iran. Int. J. Environ. Res., 8(4):871-886.
- Ibrahim, A.K., Yakubu, H., Askira, M.S. 2014. Assessment of Heavy Metals Accumulated in Wastewater Irrigated Soils and Lettuce (Lactuca sativa) in Kwadon, Gombe State Nigeria. American-Eurasian J. Agric. & Environ. Sci., 14 (6): 502-508.
- Alghobar, M.A., Suresha, S. 2017. Evaluation of metal accumulation in soil and tomatoes irrigated with sewage water from Mysore city, Karnataka, India. Journal of the Saudi Society of Agricultural. 16(1) 2017: 49-59.
- 7-Meng, W., Wang, Z., Hu, Beibei, Z., Hongyuan Lic, W., Goodman, R.C. 2016. Heavy metals in soil and plants after long-term sewage irrigation at Tianjin China: A case study assessment. Agricultural Water Management 171:153–161.
- Bashir, F., Kashmiri, M.A., Shafiqa, T., Tariqa, M. 2009. Heavy metals uptake by vegetables growing in sewage irrigated soil: relationship with heavy metal fractionation in soil.Chemical Speciation and Bioavailability 21(4):199-209.
- Khan, S., Cao, Q., Zheng, Y.M. , Huang, Y.Z., Zhu, Y.G. 2008.Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China. Environmental Pollution 152: 686-692.
- Tabari, M., Salehi, A. 2012. Impact of irrigation by municipal sewage on accumulation of heavy metals in soil. Journal of Environmental Science and Technology. 13(4): 49-60 (In Persian).
- Beigi Harchegani, H., Banitalebi, G. 2013. The Effect of twenty-three years of surface irrigation with treated municipality wastewater on soil loadings, transfer to wheat and corn grains, and related health risks of some heavy metals. Journal of Water and Soil. 27(3):570-580 (In Persian).
- Christou, A., Eliadou, E., Michael, C., Hapeshi, E., Fatta-Kassinos, D. 2014 Assessment of long-term wastewater irrigation impacts on the soil geochemical properties and the bioaccumulation of heavy metals to the agricultural products. Environmental Monitoring and Assessment 186(8):4857–4870.
- Li, P., Wang, X., Allinson, G., Li, X., Xiong, X. 2009. Risk assessment of heavy metals in soil previously irrigated with industrial wastewater in Shenyang, China. Journal of Hazardous Materials 161(1): 516–521.
- Statistical yearbook of Lorestan Province. 2011. 522 pages (In Persian).
- Maleki Rad, Z., Baharvand, S., Nouryazdan, A., Amini Kia, A. 2011. Geological study of Lorestan plains and its impact on the quality and quantity of water resources using satellite data. Regional Conference on Geology of Iran Plateau. Islamic Azad University of Zarand (In Persian).
- Tabandeh, L., Taheri, M., 2016. Assessment of pollution and relationship between heavy metals Concentration in soil and leafy vegetables in Zanjan Province. Iranian Journal of Soil Research. 30(1):49-60 (In Persian).
- Kabata-pendias, A., Pendias, H., 2001. Trace elements in soils and plants. 3rd edition. CRC Press, Boca Raton, Florida, 413 pp.
- FAO/WHO. 2001. Food additives and contaminants, Joint Codex Alimentarius Commission, FAO/WHO. Food standards Programme, ALINORM 01/12A.
- Zafarzadeh, A., Mehdinejad M.H., Amani, N. 2015. Accumulation of heavy metals in agricultural soil irrigated by sewage sludge and industrial effluent (case study: Agh ghallah Industrial Estate. J Mazandaran Univ Med Sci. 25(121): 217-226 (In Persian).
- Rattan, R. K., Datta, S. P., Chhonkar, P. K., Suribabu, K., & Singh, A. K. 2005. Long-term impact of irrigation with sewage effluents on heavy metal content in soils, crops and groundwater-a case study. Agriculture, Ecosystems & Environment, 109 (3 – 4): 310 – 322.
- Xu, J., Wu, L., Chang, A. C., Zhang, Y. 2010. Impact of long- term reclaimed wastewater irrigation on agricultural soils: a preliminary assessment. Journal of Hazardous Materials, 183 (1 – 3): 780 – 786
- Mojiri, A. 2011. Effects of Municipal Wastewater on Physical and Chemical Properties of Saline Soil. J. Biol. Environ. Sci., 5(14): 71-76.
- Rusan, M, Hinnawi, S, Rousan, L. 2007. Long term effect soil and plant quality parameters. Desalination. 215: 143-152.
- Jahantigh, M .2008. Impact of Recycled Wastewater Irrigation on Soil Chemical Properties in an Arid Region. Pakistanian Journa l of Biological Sciences. 11(18): 2264-2268.
- Khai, N.M., Tuan, P.T, Vinh, C.N., Oborn, I. 2008. Effects of using wastewater as nutrien t sources on soil chemical properties in p eri- urban agricultural systems. VNU Journal of Science, Earth Sciences. 24: 87-95.
- Friedel, J.K., Langer, T., Siebe, C., Stahr, K. 2000. Effects of long-term waste water irrigation on soil organic matter, soil microbial biomass and its activities in central Mexico, Biol. Fertil. Soils 31:414–421.
- Tunc, T., Sahin, U. 2015. The changes in the physical and hydraulic properties of a loamy soil under irrigation with simplerreclaimed wastewaters. Agricultural Water Management 158:213-224.
- Gupta, N., Khan, D.K., Sandra, S.C. 2008. An assessment of heavy metal contamination in vegetables grown in wastewater-irrigated areas of Titagarh, West Bengal, India. Bull. Environ. Cont. Toxicol. 80, 115–118.
- Kumar, V., Chopra A. K., Srivastava, S. 2014. Distribution, enrichment and accumulation of heavy metals in soil and Vigna Mungo L. Hepper (Black Gram) after irrigation with distillery Wastewater. J Environ Health Sci 1(1): 1-8.
- 31-Chen, Z.F., Zhao, Y., Zhu, Y., Yang, X., Qiao, J., Tianc, Q., Zhang Q. 2009. Health risks of heavy metals in sewage-irrigated soils and edible seeds in Langfang of Hebei province, China. Journal of Science Food Agriculture, 90:314-320.
- Massaquoi, L.D., Ma, H., Liu, X.H., Han, P.Y., Zuo, S.M., Hua, Z.X., Liu, D.W. 2015. Heavy metal accumulation in soils, plants, and hair samples: an assessment of heavy metal exposure risks from the consumption of vegetables grown on soils previously irrigated with wastewater. Environ Sci Pollut Res Int. 22(23):18456-68.
- Mapanda, F., Mangwayana, E.N., Nyamangara, J., Giller, K.E., 2005. The effect of longterm irrigation using wastewater on heavy metal contents of soils under vegetables in Harare, Zimbabwe. Agric. Ecosyst. Environ. 107:151–165.
- Wali, A., Colinet, G., Ksibi, M. 2014. Speciation of Heavy Metals by Modified BCR Sequential Extraction in Soils Contaminated by Phosphogypsum in Sfax, Tunisia. Environmental Research, Engineering and Management 4(70): 14–26.
- Adeyi A., Torto, N. 2014. Profiling heavy metal distribution and contamination in soil of old power generation station in Lagos, Nigeria. 1(1): 1-10.
- Etim, A. O. Ekpo, F. E., Okeke, A. I. 2016. Assessment of Heavy Metals Concentrations in Soils and Edible Vegetables Grown in Core Crude Oil Producing Communities of Ibeno, Akwa Ibom State, Nigeria. 4(1): 1-6.
- Duan, X., Zhang, G., Rong, L., Fang, H., He, D., Feng, D. 2015. Spatial distribution and environmental factors of catchment-scale soil heavy metal contamination in the dry-hot valley of Upper Red River in southwestern China. Catena 135: 59–69.
- Bansal, R.L., Nayyar, V.K., Takkar, P.N. 1992. Accumulation and bioavailablity of Zn, Cu, Mn, and Fe in soils polluted with industrial wastewater. J. Ind. Soc. Soil. Sci. 40:796–799.
- Singh, G., Bhati, M. 2005. Growth of Dalbergia sissoo in desert regions of western India using municipal effluent and the subsequent changes in soil and plant chemistry. Bioresource Technology, 96 (9): 1019-1028.
- Rieuwerts, J. S., Thornton, I., Farago, M. E., Ashmore, M. R. 1998. Factors influencing metal bioavailability in soils: preliminary investigations for the development of a critical loads approach for metals. Chemical Speciation and Bioavailability, 10(2): 61-75(15).
- Salehi, A., Tabari, M., Mohammadi, J., Ali Arab, A. 2008. Accumulation of Ni, Cu, Zn and Pb in soil and leaf of Robinia under the influence of urban sewage. Pajouhesh and Sazandegi, 92-100.
- Ungaro, F., Ragazzi, F., Cappellin, R., Giandon, P. 2008. Arsenic concentration in the soils of the Brenta Plain (Northern Italy): Mapping the probability of exceeding contamination thresholds. Journal of Geochemical Exploration 96(2–3):117–131.
- European Union, 2002. Heavy Metals in Wastes, European Commission on Environment.http://ec.europa.eu/environment/waste/studies/pdf/heavy metalsreport.Pdf> (accessed 12.06.12)
- Luo, C., Liu, C., Wang, Y., Liu, X., Li, F., Zhang, G.G., Li, X. 2011. Heavy metal contamination in soils and vegetables near an e-waste processing site, south China. J. Hazard. Mater. 186:481–490.
12. Karimi, B., Abdi, CH., Fathi- Tilko, Z., Gavilian, H. 2016. Effect of Irrigation with Treated Urban Wastewater on Heavy Metals Accumulation and Distribution in Soil Profile under Corn and Tomato. Water Research in Agriculture30(1):89-101 (In Persian).