Almost three-quarters of the Chesapeake Bay’s tidal waters are considered impaired by chemical contaminants. These contaminants include pesticides, pharmaceuticals, metals and more, and can harm the health of both humans and wildlife. From the insecticides that are put on farm fields to the cleaners we use to disinfect our homes, contaminants can enter the Bay and its tributaries in several different ways. While production bans have lowered the presence of some contaminants in the watershed, others are still widely used today.
Two kinds of chemical contaminants can be found in the Chesapeake Bay: metals and organics.
The most common metal found in the watershed is mercury. A 2010 report from the U.S. Environmental Protection Agency (EPA) found the extent and severity of mercury contamination to be widespread in the watershed. Contamination with metals like aluminum, chromium or iron, on the other hand, is more often localized.
Common organic chemical contaminants include PCBs, PAHs and pesticides:
Pharmaceuticals and personal care products are an emerging concern in the region. These contaminants can appear in our landfills and our wastewater, and have been linked to behavior changes and reproductive disruptions in fish and other species.
There are four general sources that push chemical contaminants into the Chesapeake Bay and its tributaries:
Some of the most common chemical contaminants in the Chesapeake Bay watershed can persist in the environment for a long time. These contaminants bind to sediment or build up in the tissues of fish and other organisms, moving through the food web in a process called bioaccumulation. During bioaccumulation:
Because the consumption of contaminated fish and shellfish can cause health problems in humans, cities and states issue fish consumption advisories in areas where chemical contaminants are a concern. The District of Columbia, for instance, has issued advisories for all of its water bodies, asking the public not to consume bottom-feeding fish like catfish, carp or eels.
Different chemical contaminants can affect the survival, growth and reproduction of fish and wildlife in different ways. Exposure to PAHs, for instance, has been linked to the development of liver tumors in brown bullhead catfish; exposure to pesticides has been linked to eggshell thinning in wild birds; and several studies have shown that PCB concentrations in bald eagle eggs can contribute to their failure to hatch.
Almost three-quarters of the Chesapeake Bay’s tidal waters are considered impaired by chemical contaminants. But the EPA has identified three “regions of concern” that show significant problems:
As part of the 2014 Chesapeake Bay Watershed Agreement, Chesapeake Bay Program partners committed to the goal of ensuring that the Bay and its rivers are free of effects of toxic contaminants on living resources and human health. This goal includes two parts: to continually increase our understanding of the impacts and mitigation options for toxic contaminants, and to continually improve practices and controls that reduce and prevent the effects of toxic contaminants below levels that harm aquatic systems and humans.
For Chesapeake Bay restoration to be a success, we all must do our part. Our everyday actions can have a big impact on the Bay. By making simple changes in our lives, each one of us can take part in restoring the Bay and its rivers for future generations to enjoy.
To lower chemical contaminants in the Bay watershed, consider using non-toxic pesticides or chemical-free cleaning and personal-care products. You can also follow safe and legal disposal methods for paint, motor oil and other household chemicals, and keep pharmaceuticals out of our waterways by returning unused medicine to a consumer drug return location or fouling it with coffee grounds or cat litter before putting it in the trash.
A research effort seeks to determine the extent of plastic pollution in the Chesapeake
The amount of road salt, in tons, applied across the Chesapeake Bay watershed each year
Intersex characteristics tied to endocrine-disrupting chemicals
Decades of reintroduction and careful monitoring have New York seeing healthy bald eagle populations
The amount of Pennsylvania-caught sport fish you are advised to consume in a given week
Based on the list of impaired and threatened waters that states submitted to the U.S. Environmental Protection Agency in 2012, 74 percent of the 92 tidal segments analyzed in the Chesapeake Bay were partially or fully impaired by chemical contaminants.
Fish biologist Vicki Blazer with the U.S. Geological Survey (USGS) brings her team to the Shenandoah River in Front Royal, Va., to collect and study smallmouth bass, a species in which intersex characteristics have been linked to chemical contaminants in the Chesapeake Bay region.
Intersex conditions occur when exposure to chemicals disrupts the hormonal systems of an animal, leading to the presence of both male and female characteristics in an animal that should exhibit the characteristics of just one sex in its lifetime. In the case of smallmouth bass, male intersex fish are found with immature eggs in their testes, which indicates exposure to estrogenic and anti-androgenic chemicals.
“The sources of estrogenic chemicals are most likely complex mixtures from both agricultural sources, such as animal wastes, pesticides and herbicides, and human sources from waste water treatment plant effluent and other sewage discharges,” says Blazer, who first discovered intersex characteristics in fish while studying fish kills in the South Branch of the Potomac River and the Shenandoah River.
Publication date: July 01, 2002 | Type of document: Report | Download: Electronic Version
This report represents the coordinated effort of a team of scientists from various institutes, who continue a long series of studies aimed at toxicological and chemical characterization of the Chesapeake Bay.
Publication date: January 01, 2001 | Type of document: Report
An assessment of ambient toxicity of Delaware public peninsula creeks where agriculture is the dominant land use. The assessment evaluates potential persistent impacts and potential intermittent or pulsed impacts. Three watershed…
Publication date: December 01, 2000 | Type of document: Agreement | Download: Electronic Version
This strategy commits to voluntary efforts that build on the successes of the state and federal regulatory programs and go beyond compliance /existing regulatory point and nonpoint source programs to preclude the need for costly regulations…
Publication date: December 01, 2000 | Type of document: Fact Sheet | Download: Electronic Version
Chemicals of concern include chemical contaminants identified in the 1999 Toxics Characterization that are at levels that may cause toxic impact, chemical contaminants responsible for listing waterbodies as impaired or threatened, and…
Publication date: May 01, 1996 | Type of document: Report
The primary objectives of this report are to describe the spatial patterns in the distribution of sediment chemical contaminants in Chesapeake Bay and to compare sediment chemical contaminant concentrations in Chesapeake Bay to sediment…
Publication date: March 01, 1995 | Type of document: Report
The purpose of this document is to present a geographical targeting approach for focusing chemical contaminant remediation, reduction, prevention, protection, and assessment actions within the Chesapeake Bay basin.
Publication date: July 01, 1993 | Type of document: Report | Download: Electronic Version
The Chesapeake Bay Groundwater Toxics Loading Workshop was held April 15-16, 1992, at the U.S. EPA Chesapeake Bay Program Office. Workshop participants reviewed and discussed available information on results from groundwater studies and…
Publication date: February 01, 1993 | Type of document: Report
The Chesapeake Bay Contaminated Sediment Critical Issue Forum was structured to seek a technical consensus on a series of questions related to the magnitude and extent of contaminated sediments within the Bay; and how that affects the…