Contaminants of Emerging Concern
What are Contaminants of Emerging Concern?
A graphic of the chemical composition of an emerging contaminant. 

Contaminants of emerging concern (CECs) are chemicals that are present in substances or products used by humans that can get into surface waters and groundwater, potentially impacting water quality, aquatic species and drinking water sources. 

While CECs have been detected in humans and other living organisms and have been found to persist in the environment, many are currently unregulated and not routinely monitored.

Examples include phthalates, perfluoroalkyl and polyfluoroalkyl substances (PFAS), brominated flame retardants (PBDEs), nanoparticles and pharmaceuticals and personal care products (PPCPs).

Most of these compounds have been detected in surface waters at very low concentrations. 

A growing body of information on the adverse effects of CECs, as well as improved analytical detection methods, have caused increased interest and concern about how these substances impact our water resources. 

A number of efforts have been undertaken within the Basin by the DRBC, the basin states and the U.S. EPA to identify CECs and understand their presence, sources, pathways, persistence and how they degrade in surface water.

From 2007-2009, DRBC conducted a Pilot Monitoring Survey (pdf) to investigate the presence and concentration of PPCPs, PFAS and PBDEs in the ambient waters of the tidal Delaware River.

In 2013, DRBC and the Water and Environmental Technology (WET) Center at Temple University partnered on a grant-funded survey to study CECs in several southeastern Pennsylvania tributaries to the tidal Delaware River. Tributaries surveyed included the Neshaminy, Perkiomen and Wissahickon creeks and the Schuylkill River, all of which have numerous municipal and industrial discharges to surface water. Ten sampling sites were surveyed, the chosen locations above and below potential source discharges for CECs. The survey was completed in March 2014. 

The DRBC continues to cooperate with the basin states, U.S. EPA and academics on a prioritized list of PPCPs, PFAS and polybrominated diphenyl ethers in order to further evaluate sources, fate and effects in surface water, sediment and fish tissue. 

Commission staff are also developing a DRBC Contaminants of Emerging Concern Strategy in consultation with its Toxics Advisory Committee (TAC). 

Examples of & Monitoring for CECs


Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a diverse group of compounds that have varying degrees of persistence, toxicity and bioaccumulation in the environment.

Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS) are the most extensively produced and studied of the PFAS.

Having unique properties to repel both water and oil, they are found in a variety of industrial and household products such as stain repellant textiles, fire-fighting foams and paper coatings. 

While there is still much to be learned about the effects of PFAS on human and ecological health, exposure from drinking water is a concern.

Monitoring for PFAS:

The DRBC has an ongoing monitoring program for PFAS in the main stem Delaware River, examining surface water, fish tissue and sediment.

Available data for surface water show PFAS levels are below current EPA and basin state human health advisory levels in segments of the Delaware River designated as drinking water sources.

However, PFAS levels observed in fish indicate that further evaluation of risk to human health and wildlife is warranted in the Delaware River. 

In FY 2021-2022, DRBC will collect PFAS data along 231 miles of the main stem Delaware River, between Narrowsburg, N.Y. and Salem River, N.J. Multiple tributaries will also be sampled in order to inform fish consumption advisories. Data collected may also be used by DRBC and other state and government agencies as the scientific basis for the development of future PFAS reduction strategies. DRBC will work with its various advisory committees (e.g., the TAC, MACC and WQAC) to solicit input on this effort from experts and stakeholders in the Basin. This project is being supported with grant funding from the Delaware Watershed Conservation Fund, Pennsylvania Coastal Zone Management and the U.S. EPA.

Another project, funded by a grant from the Pa. Department of Environmental Protection, will conduct a research study to focus on PFAS in the Delaware River Estuary.


1,4-Dioxane is a synthetic industrial chemical used as a solvent in products such as adhesives, resins, oils and waxes and wood pulping.

Other uses include: a stabilizer for chlorinated organic solvents; in the manufacture of pharmaceuticals, certain plastics and rubber; and it appears as a byproduct of surfactants used in personal care products, detergents and cosmetics.

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.

Learn more: 1,4-Dioxane Fact Sheet (U.S. EPA; pdf)

Monitoring for 1,4-Dioxane:

DRBC is part of a working group that includes representatives from the New Jersey Department of Environmental Protection (NJDEP), the Pennsylvania Department of Environmental Protection (PADEP) and water/wastewater utilities.

The working group has been coordinating to conduct enhanced sampling and assessment to identify potential source(s) of the contaminant and recommend a course of action to address potential risks to the environment or public health.

For additional information from the NJDEP on 1,4-Dioxane in the Delaware River:

DRBC has engaged its Toxics Advisory Committee, and, in addition to the above-mentioned monitoring efforts, will continue monitoring for 1,4-Dioxane via its Delaware Estuary Water Quality Monitoring and Special Tributary Monitoring programs.

Presentations and Reports

The below presentations and reports are by DRBC staff or given at DRBC advisory committee meetings.

Contaminants of Emerging Concern (CECs):

Pharmaceuticals and Personal Care Products (PPCP):

Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS):


Informational Links
Drug Take-Back/Disposal Information