Occurrence and co-occurrence of perchlorate and nitrate in California drinking water sources Perchlorate, a chemical that affects the ability of the thyroid to absorb iodide, has been detected in many drinking water sources, mainly groundwaters. Perchlorate enters groundwater via permeation from surface water; other contaminants can enter groundwater in the same fashion. The purpose of this study was to determine the overall distribution of perchlorate and nitrate in California drinking water sources and the co-occurrence (if any) of nitrate and perchlorate. The study used the California Department of Health Services Division of Drinking Water and Environmental Monitoring database of all source water monitoring results, including those for nitrate and perchlorate. Data for nitrate (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) and perchlorate (1997)(1998)(1999)(2000)(2001)(2002)(2003) were queried, and results (including nondetects) were averaged. A similar query was performed for all results above the reporting limit. All sources with positive results for perchlorate were queried for nitrate results. Nitrate results collected within 180 days of a positive perchlorate result were used. Results indicated that the mean perchlorate level in California drinking water sources was 3.6 µg/L, and the mean nitrate level was 21,000 µg/L. Among sources with positive perchlorate results, the mean perchlorate result was 12 µg/L, and the mean nitrate result was 39,000 µg/L for nitrate. A weak but statistically significant correlation was found between the concentrations of perchlorate and nitrate (R 2 = 0.31, p < 0.001).

Study of drinking water terms of Physico chemical parameters like pH, Total dissolve solid (TDS), Total hardness, Total alkalinity, Chloride, Sulphate, Calcium, Magnesium, Nitrate values, Chemical oxygen demand (COD), Biological oxygen demand (BOD), Fluoride and Turbidity. Measurement is done for six stations of Rajula Taluka of Amreli district. All the parameter are measured with respected to three different seasons such as WINTER, SUMMER and MONSOON. Results obtained are compared in terms of their highest value and lowest values among six stations in terms of 13 parameters.