DNREC and the DHSS Division of Public Health are working with federal agencies to protect the environment and public health in Delaware from the effects of a group of synthetic chemicals known as PFAS.
Per- and polyfluoroalkyl substances (PFAS) include thousands of synthetic chemicals including PFOA, PFOS, and GenX. They have been used throughout the world in manufacturing, firefighting, and consumer products since the 1940s.
The state maintains a list of sites being investigated by DNREC for per- and polyfluoroalkyl substances (PFAS) in drinking water, groundwater or surface water in Delaware.
PFAS do not readily break down in the environment and can accumulate in living things. Some toxicological studies have found that exposure to these substances can cause serious health effects.
PFAS are considered “emerging contaminants” by federal environmental and public health regulators. A group of state and federal agencies are investigating PFAS, their sources, and their presence in the environment. This group includes DNREC, the Delaware Department of Health and Social Services, the US Environmental Protection Agency, the US Geological Survey, and the CDC’s National Center for Environmental Health/Agency for Toxic Substances and Disease Registry.
When PFAS are detected in public drinking water in Delaware at concentrations above the EPA’s health advisory limit (70 parts per trillion), the group implements a response plan, which may include alternate sources of water and/or water treatment, to ensure that public water supplies are safe to consume.
In 2018, the DNREC Division of Waste and Hazardous Substances adopted a policy to define where sampling for PFAS may occur in groundwater and surface water within the state. The policy outlines that DNREC added PFOA and PFOS as hazardous substances regulated under HSCA, and details pertinent aspects of the addition, as well as expectations related to sampling and characterization of these emerging contaminants.
The federal Safe Drinking Water Act governs the quality and testing of all public drinking water supplied by water systems in the United States. The EPA works with states, localities and water suppliers to implement drinking water regulations. Drinking water supplied by public systems in Delaware is regulated by the Division of Public Health to ensure compliance with the National Primary Drinking Water Regulations.
The National Primary Drinking Water Regulations are legally-enforceable standards and treatment techniques that include maximum contaminant levels for chemicals. The EPA has not yet established a maximum contaminant level for any PFAS.
Delawareans who do not have public drinking water generally get their water from private wells. Groundwater (water stored in aquifers below the surface of the earth), directly supplies all private wells. The Safe Drinking Water Act does not apply to drinking water from private wells.
Sampling for PFAS is best done by a professional. DNREC recommends using environmental consulting firms certified to perform work in Delaware under the Hazardous Substance Cleanup Act (HSCA), as well as DNREC-approved laboratories.
Laboratory analysis for PFOS and PFOA by EPA Drinking Water Method 537 may cost $400 or more. This does not include the cost of collecting the sample by the environmental consulting firm.
Water contaminated with PFAS can be treated with carbon filters and reverse osmosis. The American National Standards Institute (ANSI) publishes standards (NSF/ANSI 53 and 58) related to the removal of PFAS through these systems.
The National Sanitation Foundation lists products it has certified to reduce PFOA/PFOS in drinking water.