ارزیابی غلظت آرسنیک، روی، سرب و مس منابع آب زیرزمینی دشت تویسرکان و تهیه نقشه توزیع مکانی عناصر

Background and purpose: Pollution of exploitation water resources is increasing throughout the world. Continuous monitoring of these resources could play a key role in reducing such pollutions. This study aimed at evaluating As, Zn, Pb and Cu concentrations in groundwater resources in Toyserkan Plain and preparing the zoning map through GIS. Material and Methods: Groundwater samples were collected from10 selected stations during two seasons in 2012. The samples were filtered (0.45 μm) and maintained cool in polyethylene bottles. Samples were taken for the analysis of cations, the former was acidified with HNO3 (suprapur Merck, Germany) to pH lower than 2. Minor elements (As, Zn, Pb and Cu) were determined using ICP-OES (Varian, 710-ES, Australia). All statistical analyses were performed using SPSS. Kriging method was used for preparing spatial distribution maps of elements in groundwater samples. Results: The results showed that mean concentrations of As, Zn, Pb and Cu in groundwater samples were 3.68±0.76, 3.85±0.84, 1.66±0.35 and 8.59±1.01 ppb, respectively in spring, and 3.99±0.83, 6.30±1.12, 1.85±0.71, and 12.49±1.85 ppb, respectively in summer. The mean concentrations of evaluated metals in groundwater samples were significantly different compared to those of the WHO and IranDOE permissible limits for drinking and agricultural use (p< 0.05). In fact, the mean concentrations of aforementioned metals were significantly lower than the permissible limits. Conclusion: Currently the groundwater resources of Toyserkan Plain are not polluted with heavy metals, but long-term excessive use of agricultural inputs and construction of polluting industries can cause a threat to groundwater resources in this area.