Document Type : Research Article

Authors

urmia university

Abstract

Introduction: Over the past decades, due to climate change and water scarcity, the recovery and use of urban wastewater, especially in arid and semi-arid climates, has increased. But since wastewater is considered as an unconventional source of water, its use in agriculture requires special management which, while benefiting from it, does not have environmental and health hazards in soil, plant and surface water and underground water resources. On the other hand, sewage systems often have significant amounts of heavy and toxic metals, the type and amount of which varies from place to place, and even in the specific location, over time. The soil also has a limited capacity to absorb and maintain these elements, and if their concentration exceeds the permitted range, they can cause pollution of the water, soil, plant and human cycle. Therefore, the present study was conducted to investigate the effect of irrigation with treated wastewater in Urmia city on concentrations, distribution and contamination of Zn, Cu, Cd, Pb and Ni elements.
Materials and Methods: In field work, 6 soil profiles (5 profiles from the wastewater-irrigated soils and a profile from the well-irrigated soil as control soil) were dug, described, and sampled. At around each profile, composite soil samples were also obtained in the root depth of the area (Ap horizon, the depth of 30 cm). Soil samples were first air-dried and passed through a 2-mm sieve and then analyzed for the determination of heavy metals. The available and total fraction of zinc (Zn), copper (Cu), cadmium (Cd), leads (Pb), and nickel (Ni) were extracted by DTPA method and concentrated acid (HNO3) procedure, respectively. The content of Zn, Cu, Cd, Pb and Ni were determined by an atomic absorption spectrophotometer (Shimadzu AA-6300). Descriptive statistics were conducted using SPSS 16 for Windows. In order to study the effect of irrigation with treated wastewater on the extent of contamination of heavy metals, the AP (availability percentage), PI (Single-factor pollution index), NPI (Nemerows pollution index), and PLI (Pollution load index) in the affected soils with this wastewater was calculated. Also, all soil and water experiments were performed in 3 replicates and then, using the excel data software category, tables and charts were plotted.
Results and Discussion: The soils were alkaline and calcareous as characterized by high pH, ranging from 7.6 to 8, and calcium carbonate equivalent, ranging from 30 to 42%. On average, the value of the available fraction of the examined metals in the wastewater-irrigated soils ranged from 1.9 to 3.5 mg kg-1for Zn, 2.5- to 3.5 mg kg-1for Cu, 0.4 to 0.62 mg kg-1for Cd, 2 to 2.9 mg kg-1for Pb, and 1.34 to 1.75 mg kg-1for Ni. Comparing to the control, irrigation with wastewater resulted in a considerable build-up in the available fraction of the metals in the rank of Ni (79-142%)> Cd (54-125%)> Zn (35-73%)> Cu (13-87%)>Pb (6-32%). These patterns can be due to the quality and quantity of the used wastewater and impact of the used wastewater with its receiving soils. Similar to the available fraction, there was an increasing trend in the total fraction of metals in the order of Cd> Zn>Pb> Ni> Cu following wastewater irrigation. In this context, the mean content of total Zn, Cu, Cd, Pb, and Ni in wastewater-irrigated soils was as 51-157%, 10-32%, 243-310, 11-203%, and 13-126% higher than those of control soil, respectively. In spite of such enrichment, only the Cd values exceeded the maximum acceptable limits. The AP index is an appropriate index to compare the mobility potential and the toxicity of heavy metals in soil. In this study, the highest rate of this index among the heavy metals was related to Cd and its lowest level was related to Pb, which showed more toxicity and more mobility of Cd compared with other elements. The average of single-factor pollution index of five elements was observed in sequence Cd> Zn> Ni>Pb> Cu that the element of Cd had the highest class of PI (class 4). The highest and lowest of NPI values of five elements were observed in profiles 4 and 2, respectively. Also, the greatest effect of the five elements of this study is on the elements of Cd and Zn in the generation of this level of contamination. The pollution index of the five studied elements in irrigated soils with treated wastewater was similar to the NPI, its maximum was observed in profile 4 and Cd showed the highest effect on increasing the value of this index.
Conclusions: The results of this study showed that irrigation with sewage significantly increased the available fraction of the metals in the order of Ni (78.9-141.8%)> Cd (54.4-125%)> Zn (35.7-73.3%>Cu (13-87%)>Pb (6-32.3%) compared to the control. However, with the exception of cadmium, the available fraction of other elements was within the permissible limit. Compared to the control, in the majority of studied soils, the total fraction of the metals (with the exception of copper) was significantly increased and the lowest and highest increase associated with Cu (10-32%) and Cd (2 - 3 times). Also, the results of pollutant indices showed that the majority of the studied soils were in the low to high contamination and Cd was known as the major metal affecting the indices yield.

Keywords

1- Abedi-Koupai J.B., Mostafazadeh-Farid M., Afyuni and Bagheri M.R. 2006. Effect of treated wastewater on soil chemical and physical properties in an arid region. Plant, soil and Environmental, 52(8):335-344.
2- Bai J., Yang Z., Cui B., Gao H., Ding Q. 2010. Some heavy metals distribution in wetland soilsunder different land use types along a typical plateau lake, China. Soil & Tillage Research, 106: 344–348.
3- Chapman H.D. 1965. Cation exchange capacity. In: Black CA (ed) Methods of soil analysis, Part2. American Society of Agronomy, Madison, pp: 891-900.
4- Cheng J.L., Shi Z., Zhu Y.W. 2007. Assessment and mapping of environmental quality in agricultural soils of ZhejiangProvince, China. Journal Environmental Science, 19: 50–54.
5- Dahnke W.C., and Journal G.V. 1990. In Westerman RL (ed) soil Testing and plant Analysis: American Society of Agronomy Inc. Madison, Wisconsin, USA, 6, 120-140.
6- Farahat E., and Linderholm W. 2015. The effect of long-term wastewater irrigation on accumulation and transfer of heavy metals in Cupressus sempervirens leaves and adjacent soils. Science of Total Environment. SID, 513: 1-7.
7- FAO. 1992. Wastewater Treatment and Use in Agriculture. Irrigation and Drainage Paper, No 47, FAO, Rome, Italy.
8- Hati K.M., Biswas A.K., Bandyopadhyay K.K., and Misra A.K. 2007. Soil properties and crop yilds on a vertisol in India with application of distillery effluent. Soil & Tillage Research, 92(1-2):60-68.
9- Iranian Environmental Protection Agency Research Deputy. 1992. Sewage outlet standard. Environmental Education Office. (In Persian).
10- Kabata-Pendias A. 2010. Trace elements in soils and plants. Boca Raton (FL): CRC Press, 157-166.
11- Klay S.A., Charef A., Ayed B., Houman and Rezgu F. 2010. Effect of irrigation with treated wastewater on geochemical properties (saltiness, C,N and heavy metals) of isohumic soils (Zaouit Sousse perimeter, Oriental Tunisia). Desalination, 253:180-187.
12- Lindsay W.L., and Norvell W.A. 1978. Development of a DTPA soil test for Zinc, Iron, Manganese, and Copper. Soil science society of America Journal, 42(3), 421-428.
13- Malakouti M.J., and Gheibi M.N. 2000. Determination of critical levels of nutrients in soils, plant and fruit for the quality and yield improvements of Iran,s strategic crops. Applied Agriculture Science Publishers, Tehran, Iran. (In Persian).
14- Massas I., Ehaliotis C., Gerontidis S., and Sarris E. 2009. Elevated heavy metal concentrations in top soils of an Aegean islandtown (Greece): total and available forms, origin and distribution. Environmental Monitoring Assessment. 151: 105–116.
15- Mc Bride M.B., Richards B.K., Steenhuis T., Russo J.J., and Save S. 1997. Mobility and solubility of toxic metals and nutrients in soil fifteen years after sludge application, Soil Science. 7: 487-500. Nelson RE. 1982. Carbonate and gypsum. In: Page PL (ed) Methods of soil analysis, Part 2. American Society of Agronomy, Madison, pp: 181-199.
16- Nelson D.W., and Sommers L.E. 1996. Total Carbon, organic carbon, and organic matter. Methods of soil analysis. Part, 3(3), 961-1010.
17- Nelson R.E. 1982. Carbonate and gypsum. In: Page PL (ed) Methods of soil analysis, Part 2. American Society of Agronomy, Madison, pp: 181-199.
18- Parsfar N., Maroufi S., Rahimi A.H., and Maroufi H. 2015. Evaluation of the rate of Cd, Zn, Cu and Pb in irrigation soil with municipal wastewater. Journal of Water and Soil Science, Vol. 25, No.1, Page 1 to 25. (In Persian with English abstract).
19- Rattan R.K., Datta S.P., Chhonkar P.K., SuribabuK and 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 and Environmental, 109:310-322.
20- Ramos-Miras J.J., Roca-Perez L., Guzman-Palomino M., Boluda R., and Gil C. 2011. Background levels and baseline values of available heavy metals in Mediterranean greenhouse soils (Spain). Journal of Geochemical Exploration, 110(2), 186-192.
21- Rezapour S., Jafarzadeh A.A., Samadi A., and Oustan S. 2010. Distribution of iron oxides forms on A transect of calcareous soils, north-west of Iran. Archives of Agronomy and Soil Science, 56:165-182.
22- Rezapour S., and Samadi A. 2011. Soil quality response to long-term wastewater irrigation in Inceptisols from a semi-arid environment. Nutrient cycling in Agroecosystems, 91(3), 269-2.
23- Rezapour S., Samadi A., and Khodaverdiloo H. 2012. An Investigation of the soil property changes and Heavy metal accumulation in relation to long-term wastewater irrigation in the semi-arid Region of Iran. Soil and Sediment contamination: An International Journal, 20, 841-856.
24- Rezapour S., Kouhinezhad P., Samadi P., and Rezapour M. 2015. Level, pattern, and risk assessment of the selected soil trace metals in the calcareous-cultivated Vertisols. Chemical Ecology, 8:692-706.80.
25- Rezapour S., Kouhinezhad P., and Samadi A. 2017. The potential ecological risk of soil trace metals following over five decades of agronomical practices in a semi-arid environment. Chemistry and Ecology, 68-78.
26- Sharma R.K., Agrawal M., and Marshall F. 2007. Heavy metal contamination of soil and vegetables in suburban areas of Varanasi, India. Ecotooxicology and Environmental Safety, 66(2):258-266.
27- Smith J.L., and Doran J.W. 1996. Measurements and use of pH and electrical conductivity for soil quality analysis. In Methods for assessing soil quality. SSSA special publication 49 (pp. 169-185). Madison: Soil Science Society of America.
28- Tabari M., Salehi A., and Ali-Arab A.R. 2008. Effects of wastewater application on heavy metals (Mn, Fe, Cr and Cd) contamination in a black locust stand in semi-arid zone of Iran. Research Journal of Environmental Science, 7(4): 382-388.
29- Toze S. 2006. Reuse of effluent water (benefit and risks). Agriculture Water Management, 80(1-30):147-59.
30- U.S. Environmental Protection Agency (EPA). 1993. Standards for use of disposal of sewage sludge, Final reles, 40 CFR, Parts 257, 403 and 503. Federal Register, 58 (32): 9248 – 9415.
31- Urmia Environmental Organization. 2008. Archive of figures.
32- WHO. 2006. Guidelines for the safe use of wastewater, excreta and grey water, part II, Geneva.
33- Yu L., Zhang B., and Zhang S.Q. 2004. Heavy metal elements pollution evaluation on the ecological environment of the Sanjiang Plain based on GIS. Chinese Journal of Soil Science, 35(5), 529-532.
CAPTCHA Image