s Samani - Department of Geology, Faculty of Natural Science, University of Tabriz, Iran.
a.a Moghaddam - Department of Geology, Faculty of Natural Science, University of Tabriz, Iran.
m Vadiati - Department of Geology, Faculty of Natural Science, University of Tabriz, Iran.
z.n Jahromi - Iran Water Resources Management Institute, Tehran, Iran.

There are several factors influencing the water quality based on its usage. An attempt has been made to understand the ground water quality near the some industrial parts of Marvdasht city. the following 8 parameters have been considered: pH, dissolved oxygen, BOD (biochemical oxygen demand), Fecal coliform, temperature, total phosphate, nitrates and total solids, in the groundwater of three Marvdasht, Kharameh and Zarghan plains, during spring and fall(June-2012 and December-2013), to determine spatial distribution of groundwater quality and to identify places with the best quality for drinking, based on Water Quality Index calculation and Geographical Information System, due to industrialization, urbanization and agricultural activity. Groundwater samples were collected from 120 wells. The values of WQI for all samples were found in the range of 43.3 to 80.5 in the spring season while it was 44.7 to 82.3 in the fall season. In spring 10% and in fall season 7.5% of the water samples in Zaraghan and Dashtbal–Lanetavosi and Kharameh plains fall within the bad categories based on National Sanitation Foundation (NSF). The analysis reveals that the groundwater of these plains needs some degree of treatment before consumption, and it also needs to be protected from the perils of contamination.

Geographical information system ، ، ، Water quality index ، ، Contamination ، ، Marvdasht plain