Occurrence of perchlorate in drinking water, groundwater, surface water and human saliva from India

Abstract

Perchlorate ( ClO 4 - ), which is used as an oxidizer in jet and rocket fuels, pyrotechnic devices and explosives, is a widespread contaminant in surface waters and groundwater of many countries. Perchlorate is known to affect thyroid function. Despite the compound’s widespread occurrence and potential health effects, perchlorate levels in drinking water in India are not known. In this study, water samples collected from 13 locations in six states ( n = 66), and saliva samples collected from four locations in three states ( n = 74) in India, were analyzed for perchlorate using high performance liquid chromatography interfaced with tandem mass spectrometry (HPLC–MS/MS). Perchlorate was detected in most (76%) of the water samples analyzed at concentrations above the quantitation limit of 0.02 μg L −1; concentrations ranged from <0.02 to 6.9 μg L −1 (mean: 0.42 ± 1.1 μg L −1; median: 0.07 μg L −1). Mean concentrations of perchlorate in drinking water, groundwater, bottled water, surface water and rain water were 0.1, 1.0, <0.02, 0.05 and <0.02 μg L −1, respectively. From a total of 66 water samples analyzed, only three samples contained perchlorate levels above 1 μg L −1; all three were groundwater samples. Perchlorate was found in the saliva samples analyzed at concentrations above 0.2 μg L −1 and up to 4.7 μg L −1 (mean: 1.3 ± 1.3 μg L −1; median: 0.91 μg L −1). No remarkable differences in perchlorate concentrations were found among the sampling locations of water or saliva or in subgroups stratified by gender or age. Perchlorate concentrations in water samples from India are one to two orders of magnitude lower than the concentrations reported for the United States.