Basis of the Massachusetts Reference Dose and Drinking Water Standard for Perchlorate

Abstract

ObjectivePerchlorate 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 sourcesMA 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 synthesisWe used a weight-of-the-evidence approach to evaluate perchlorate risks, paying particular attention to sensitive life stages. A health protective RfD (0.07 μg/kg/day) was derived using an uncertainty factor approach with perchlorate-induced iodide uptake inhibition as the point of departure. The MA DWS (2 μg/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.ConclusionsCurrent 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.

Occurrence and exposure evaluation of perchlorate in indoor dust and diverse food from Chengdu, China

“…e.g., solid rocket propellants, munitions, fireworks, roadside flares, air bag inflation systems, and pharmaceutics (Urbansky, 1998;Zewdie et al, 2010). Recently, perchlorate has raised more concerns due to its persistence and ubiquitous occurrence in aquatic environment and drinking water, with concentrations ranging from below 0.1 to 2300 ng/mL (Kosaka et al, 2007;Kannan et al, 2009;Wu et al, 2010;Qin et al, 2014).…”

Chlorates(VII) removal on Dowex™PSR-2 resin

“…As a result, the individual states of the USA introduced some ristictions. The most rigorous requirements (1-2 µg/dm 3 ) were applied in the states Maryland, New Mexico i Massachusetts [13]. The higher admissible concentrations 25 and 18 µg/dm 3 were applied in California and Nevada.…”

Review on Fate, Toxicity, and Remediation of Perchlorate

“…They suggest that drinking water perchlorate level should be <6.9 mg/L, to keep the nursing infants' exposure below the RfD. Zewdie et al (2010) suggest 2 mg/L drinking water standard for perchlorate. A public health goal of 6 ppb (0.0037 mg/kg/day) was found to be adequately protective of sensitive subpopulations, including pregnant women, their fetuses, infants and people with hypothyroidism (Ting et al, 2006).…”