Responding to Emerging Contaminants: 1,4-Dioxane

The New Jersey Department of Environmental Protection is a national leader in assessing and responding to environmental and public health risks presented by emerging contaminants.

Emerging contaminants, also called contaminants of emerging concern (or CECs), is a designation that refers to a class of chemicals that present unique issues and challenges to the environmental community. Many emerging contaminants can be present in substances or products regularly used by the general public. Emerging contaminants can include chemicals present in pharmaceuticals, personal care or household cleaning products, lawn care and agricultural products, and many other applications. Emerging contaminants, some of which are not yet regulated by federal or state environmental agencies, can make it into surface waters (e.g., lakes, rivers, and streams) and groundwaters, impacting water quality, aquatic species, and potentially, drinking water sources.

DEP assesses emerging contaminants, together with the New Jersey Drinking Water Quality Institute, determines whether and how to regulate these contaminants.

1,4-dioxane, an emerging contaminant that is present in or a byproduct of many commercial/industrial and consumer products, is under evaluation by DEP. As of December 2020, DEP has established a standard for the groundwater discharges and remediation. DEP is also in the process of evaluating the setting of a drinking water standard for 1,4-dioxane.

About 1,4-Dioxane

1,4-dioxane is a synthetic chemical used as a solvent in products such as adhesives, resins, oils and waxes and wood pulping, and was formerly used as a stabilizer for chlorinated organic solvents. 1,4-dioxane is also used in the manufacture of pharmaceuticals, certain plastics and rubber, and other products.

The chemical also appears as a byproduct of surfactants used in personal care products, detergents and cosmetics. Significant exposure to 1,4-dioxane is not known to occur during showering or bathing, as the chemical is not absorbed through the skin and does not vaporize significantly into the air from drinking water. However, since scientific studies indicate that 1,4-dioxane may pose a threat to human health if ingested in sufficient amounts, the chemical is a concern for drinking water supplies.

Information on health effects of 1,4-dioxane comes primarily from studies of laboratory animals, which show that prolonged exposure to low levels of 1,4-dioxane may result in adverse health impacts. Research suggests lifelong exposure to 1,4-dioxane may be associated with an increased risk of cancer or damage to the kidneys or liver. The United States Environmental Protection Agency (EPA) has classified the chemical as “likely to be carcinogenic to humans” from long-term exposure.

1,4-Dioxane and the Delaware River

In response to the detection of the synthetic chemical 1,4-dioxane in the Delaware River, the New Jersey Department of Environmental Protection is convening an interstate task force to assess potential sources of the chemical and possible remedies.

The State will lead a working group consisting of DEP experts, Pennsylvania regulators, the Delaware River Basin Commission, and industry representatives. DEP intends for the group to conduct enhanced sampling and assessment to identify potential source(s) of the contaminant and recommend a course of action to address risks to the environment or public health.

Among issues for the group to evaluate is the recent detection of 1,4-dioxane at the Delaware River Regional Water Treatment Plant in Delran, operated by New Jersey American Water (NJAW). At the amounts presently detected by NJAW, the chemical is unlikely to pose an immediate acute health risk. Nevertheless, NJAW has made operational changes to reduce 1,4-dioxane levels in drinking water distributed by the Delran plant and intends to install new treatment at the plant. While there is no cause for alarm, the information shared by NJAW is an important preliminary data point in the evaluation of this emerging contaminant for all water systems that draw from the Delaware River.

“While we take the detection of 1,4-dioxane in the Delaware River very seriously, it is important for the public to understand that DEP does not believe that the current results pose any immediate health risk,” DEP Commissioner Catherine R. McCabe said on December 2, 2020. “New Jersey has led the nation in protecting our drinking water from chemical exposure risks, and we will continue that tradition by responding to the challenge of 1,4-dioxane, working collaboratively with our partners in the public and private sectors. We encourage water purveyors throughout the state to share information about the presence or treatment of 1,4-dioxane in source water supplies with the DEP while regulations for this emerging contaminant are in development.”

Regulating 1,4-Dioxane

There are no current federal or New Jersey drinking water standards for 1,4-dioxane. The DEP and the New Jersey Drinking Water Quality Institute are in the process of developing a 1,4-dioxane drinking water standard. This process would establish a regulatory limit for 1,4-dioxane in drinking water that is based on potential health effects from long-term consumption of affected water.

Once formally regulated, water systems would be required to monitor for the presence of 1,4-dioxane and would be obligated to take remediation measures where the elevated levels of the chemical are detected, including the potential installation of additional treatment technology. Presently, no home-treatment systems or filters have been certified to remove 1,4-dioxane.

DEP has already adopted a remediation standard for groundwater 0.4 µg/L. Of an estimated State population of 8.9 million, about 3 million people rely on ground water from public water supply wells and private domestic potable wells. The ground water quality standard for 1,4-dioxane ensures that a current and scientifically based standard to protect, maintain, and restore ground water quality is in place. The ground water quality standards also establish minimum standards for the remediation of contaminated ground water.

Health-based drinking water standards are developed using conservative assessments that consider exposure to a chemical over an entire lifetime. The USEPA has estimated the concentration of 1,4-dioxane in water corresponding to an increased lifetime cancer risk of one-in-a-million is 0.35 parts per billion (ppb), assuming consumption of two liters of water contaminated with 1,4-dioxane every day for an entire lifetime. The New Jersey Drinking Water Quality Institute is currently taking public comment on a draft Maximum Contaminant Level (MCL) of 0.33 ppb with a similar basis as the USEPA value.

Related Organizations