The Quality Variation of Groundwater in Malayer City with an Emphasis on the Impacts of Agricultural Land Use on the Quality of Water

The aim of this study was to investigate the quality of groundwater in a semi-arid environment area in Malayer,Hamedan Province, with respect to a four-year monitoring data using water quality index(WQI) with an emphasis on the agricultural land use 's impacts on the water quality. The monitoring data related to 14 water quality parameters associated with 26 sampling wells in 2012-2013 and 19 sampling wells in 2010-2011 were provided. The amount of chlorine residue in 50%percent's of the stations was zero. In addition, the fluoride in 14 stations was less than 0.5 mg/l and for 80.7 percent's of the stations the nitrate values were higher than 13 mg/l. Although, there was a significant difference between the level of some parameters between these two time periods, however, this difference was not that much noticeable.76.9 percent's of the stations were slightly to moderately polluted based on the results of water quality index. As a whole, the amount of nitrate in 21 wells (80.7 percent) was higher than the human induced standard level (13 mg/l) and in two wells were higher than the WHO permissible level (40 mg/l).The regional change of nitrate was increasing from North West to the south east part of the area. Although the overall quality of groundwater has not deteriorated according to WQI but there is a health risk of water for local people especially that is associated with the results of nitrate in the study area.