Basis of the Massachusetts Reference Dose and Drinking Water Standard for Perchlorate
نویسندگان
چکیده
OBJECTIVE Perchlorate inhibits the uptake of iodide in the thyroid. Iodide is required to synthesize hormones critical to fetal and neonatal development. Many water supplies and foods are contaminated with perchlorate. Exposure standards are needed but controversial. Here we summarize the basis of the Massachusetts (MA) perchlorate reference dose (RfD) and drinking water standard (DWS), which are considerably lower and more health protective than related values derived by several other agencies. We also review information regarding perchlorate risk assessment and policy. DATA SOURCES MA Department of Environmental Protection (DEP) scientists, with input from a science advisory committee, assessed a wide range of perchlorate risk and exposure information. Health outcomes associated with iodine insufficiency were considered, as were data on perchlorate in drinking water disinfectants. DATA SYNTHESIS We used a weight-of-the-evidence approach to evaluate perchlorate risks, paying particular attention to sensitive life stages. A health protective RfD (0.07 microg/kg/day) was derived using an uncertainty factor approach with perchlorate-induced iodide uptake inhibition as the point of departure. The MA DWS (2 microg/L) was based on risk management decisions weighing information on perchlorate health risks and its presence in certain disinfectant solutions used to treat drinking water for pathogens. CONCLUSIONS Current data indicate that perchlorate exposures attributable to drinking water in individuals at sensitive life stages should be minimized and support the MA DEP perchlorate RfD and DWS. Widespread exposure to perchlorate and other thyroid toxicants in drinking water and foods suggests that more comprehensive policies to reduce overall exposures and enhance iodine nutrition are needed.
منابع مشابه
تعیین غلظت پرکلرات در آب و خاک سطحی مناطق جنگی (مطالعه موردی: شهرستان خرمشهر)
Background and Objectives: Perchlorate, as an emerging contaminant, has attracted notice of the most individuals and organizations. Presence of perchlorate in the human body can lead to inappropriate regulation of metabolism in adults. Moreover, due to inhibition of iodide uptake in the thyroid gland, it causes neurological and behavioral problems in infants and children. United States Environm...
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