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:
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.
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Based on the 2012 303(d) assessments of 92 tidal segments analyzed 74 percent had partial or full impairments due to chemical contaminants.
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…