Human health risk assessment of unregulated organic compounds in New Jersey drinking water

Considerable quantities of organic chemicals are used by industry and consumers each year in the United States, creating the potential for contamination of limited fresh water supplies with a wide variety of organic chemicals. Although drinking water standards have been established for many organic chemicals, there is a potential for contamination of water sources with unregulated chemicals. The New Jersey Department of Environmental Protection (DEP), in conjunction with Rutgers University, has conducted a survey of public drinking water systems and has detected over 600 unregulated organic compounds in water samples from these systems. To evaluate the potential human health effects from drinking water exposure to these chemicals, a review of the scientific literature for toxicology data was conducted during this project. Toxicology data were not available for the majority of the chemicals, limiting the ability to assess the potential human health effects from drinking water exposure. Sufficient data were available to establish health based water criteria for 40 chemicals. The calculated drinking water criteria for these chemicals were greater than 1 ppb indicating that the chemicals are unlikely to present a risk to human health when present in drinking water at concentrations <1 ppb. Finally, human health risk assessments for exposure to N,N-diethyl-meta-toluamide (DEET), triclosan and acetaminophen were conducted. Acceptable daily intakes (ADIs) were derived from the available toxicology data and exposure was estimated by generating distributions for key exposure parameters using Monte Carlo analysis. The maximum estimated exposures were at least 100 fold lower than the corresponding ADIs, indicating that there is minimal risk to human health from exposure to these chemicals at reported typical concentrations in US streams.