RESUMO
Nitrate is considered as a major pollutant for groundwater resource. In recent years, the concentration of nitrate in subsurface water is increasing because due to utilization of the of using excessive amount of fertilizers and disposal of wastewater in soils. This research was carried out as descriptive study, in a rural area of Paeen Khiaban Litkooh in Amol City in 2005. In this cross-sectional descriptive study, 300 samples were collected from 50 well drinking water in different weather [wet and dry] The samples was taken from each well, 3 times in the wet air and 3 times in the dry air. Nitrate analysis method was Ultraviolet Spectrophotometer [Model Jesco 7800 U.V/Visible] at 220 and 275 nm according to "Standard methods for the examination of water and wastewater [20th edition]. The results revealed that, nitrate maximum related to well number 38 in a rural qrea with code 8 and with 20.66 mg/I Nitrate as N. Maximum of Nitrate average concerned in rural code 8 with 9.66 mg/I and minimum of nitrate average related to rural code 2 with 1.257 mg/I nitrate as N. The results indicated that nitrate was reduced when the depth of water wells increased and ford ware, the value of nitrate in deep wells is more than surface wells. The statistical analysis showed, there is a significant difference between concentrations of nitrate in surface wells drinking water in wet and dry air conditions, but there is not a significant difference between deep well drinking water. The leakage of surface water to the low depth well and lack of sanitation, may be the cause of this difference