Chemical Contamination
Chemical contaminants in water do not break down easily and persist in the environment for many years, impacting not just fish and birds, but humans as well.
Chemical contamination occurs when chemicals are either found where they shouldn’t be or are present in amounts that are higher in concentration than is considered safe.
Toxic chemicals are constantly entering the Chesapeake Bay and its rivers and streams via industrial sites, military bases, wastewater, stormwater, agriculture, and air pollution. These dangerous chemicals, including mercury and other metals, pesticides, PCBs (polychlorinated biphenyls), PAHs (polycyclic aromatic hydrocarbons), and PFAS (per- or poly-fluoroalkyl substances), persist in the environment for many years.
You can’t see them, smell them, or taste them, but these contaminants are present, causing harm to the Bay, its fish, wildlife, and people.
What are chemical contaminants?
There are many types of toxic chemicals in the waters of the Chesapeake Bay. According to the Chesapeake Bay Program, almost three-quarters of the Bay’s tidal waters are considered impaired by contaminants. Each contaminant has a unique and harmful impact, and many bioaccumulate—or build up in the body—faster than they can be eliminated.
Pesticides flow into the Chesapeake Bay primarily from surrounding farms, but also from private yards, via polluted stormwater runoff. Exposure to neurotoxic pesticides has been linked to lower birth weight, reduced IQ, delayed motor development, attention disorders, and more.
One example is Chlorpyrifos, an organophosphate insecticide used to kill pests, primarily on grain, fruits and vegetables. This extremely toxic pesticide is third on the list of toxic chemicals of concern in the Chesapeake. It is a neurotoxin, and even limited exposure during pregnancy could lead to neurobehavioral and functional issues in prenatally exposed children.
Another example is the herbicide atrazine. Used for agriculture and in lawn products, it is just one of many known to disrupt regular hormone function and cause several types of cancer. Though banned in much of the world, it is the second most commonly used herbicide in the United States.
This heavy metal, often released from the burning of coal, is a highly toxic chemical that pollutes waterways, taints fish, and subsequently can cause harm to humans that consume them. The chemical becomes more concentrated as it moves up the food chain as fish, wildlife, and people consume contaminated food. For example, the amount of mercury in fish tissue can be more than a million times higher than in surrounding water. Mercury is especially detrimental to the developing nervous system and can cause IQ deficits in children. For this reason, fetuses, infants, children, and women of childbearing age are at the greatest risk. In the Chesapeake region, governments have issued statewide fish-consumption advisories for mercury for all lakes and rivers in Pennsylvania and Maryland, and many rivers in Virginia.
In 2006, the EPA’s Chesapeake Bay Program prioritized Polycyclic Aromatic Hydrocarbons (PAHs) as among the most critical toxic contaminants to rivers, streams, and the Chesapeake Bay. These compounds make their way into our waters and our air through polluted runoff and air deposition. Sources include leaking motor oil, vehicle exhaust, the burning of fossil fuels, coal-tar pavement sealants, and more. They can harm people, birds, amphibians, fish, mammals, and plants. They are found to cause lesions, tumors, and developmental issues in fish and amphibians, and accumulate in mussels, clams, and oysters.
Sometimes called “forever chemicals,” Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) don’t break down in the environment and contaminate our water, soil, and wildlife. These chemicals are used to make products resistant to water, stains, grease, and heat, such as non-stick cookware, water and stain repellent clothing, some fertilizers, and firefighting foam. They are commonly used in personal use products and industrial processes. PFAS have been linked to detrimental fishery impacts, cancer, fish consumption advisories, reproductive impacts, and immune suppression.
Considered emerging contaminants of concern, PPCPs end up in our waters in a number of ways. Antibiotics and medications, which pass through the body as waste (both human and animal), are found in wastewater. Personal use products, from hair color to shampoo to cosmetics, which contain a range of toxic chemicals and heavy metals, are washed off into drains. People also dispose of unwanted products and medications improperly, dumping them down the sewer or putting them into the trash.
Although PCBs were banned in 1977, these highly toxic industrial compounds continue be widespread in the Bay watershed, entering our waters through accidental leaks, improper disposal, and legacy deposits that can remain in the environment for decades. Even low levels of PCBs are dangerous, as they accumulate in fish and animal tissue, traveling up the food chain. These compounds are known to cause a wide range of health problems in both wildlife and humans, ranging from cancer and birth defects to hormonal imbalances and an increased susceptibility to other diseases.
How do chemicals enter the water?
Chemical contaminants enter the water quietly, often without being seen or smelled. But by understanding their origins, we can devise ways to stop toxic chemicals from contaminating the waters of the Chesapeake Bay and causing harm to the water, fish, wildlife, and ultimately humans, as well.
Left unchecked, industrial facilities (like the old Sparrows Point Steel Mill in Baltimore) are notorious for violating pollution regulations for water, air, and toxic wastes that foul local waterways and impact communities. Toxic chemicals released by industrial facilities include benzene, chromium, lead, naphthalene, benzo(a)pyrene, and zinc, among others. These chemical pollutants can migrate beyond the facility and surrounding land, ending up in the water we drink and fish we eat, presenting a risk to human health and the environment. They contaminate groundwater and sediment, eventually seeping into local creeks, rivers, and ultimately the Bay.
Stormwater runoff or urban/suburban polluted runoff picks up oil, pesticides, fertilizer, and other chemicals as it flows across lawns, roads, driveways, and parking lots, contaminating nearby streams and storm drains. This polluted runoff is significant and challenging to control.
Pharmaceuticals and chemicals from personal care products end up in wastewater. They cannot be removed at wastewater treatment plants, so they find their way into our rivers and the Bay.
Coal-fired power plants are the largest single source of mercury emissions in the U.S. They also produce microscopic soot particles that spread by the wind over hundreds of miles. While renewable energy sources are replacing the need for many coal-fired power plants, those in the Chesapeake Bay airshed continue to affect our water and put human health at risk. In addition to toxic contaminants, one-third of the Bay’s nitrogen pollution comes from the air.
How can we help stop water contamination?
Coal-fired power plants are the largest single source of mercury emissions in the U.S. They also produce microscopic soot. The best way we can reduce toxic contamination and reduce nitrogen, phosphorus, and sediment pollution are largely the same: Stop pollutants at their source.
We’re working hard to control polluted runoff from urban and suburban areas as well as from farms. When we limit urban, suburban, and agricultural polluted runoff, less pollution of all kinds will end up in our waterways and food. The same goes for upgrading wastewater treatment technology and reducing the amount of waste we have to treat before putting it back into the environment.
CBF also fights for rules and regulations that reduce air emissions of toxic contaminants, like the Mercury and Air Toxic Standards (MATS) rule to cut mercury emissions from power plants.
Chemical contamination of our water can be curbed and even reversed, but we need to take action. Some things you can do as an individual include:
- Dispose of pharmaceuticals responsibly. More and more pharmacies offer special disposal bins for medications.
- Be cautious when fertilizing your lawn and garden so that excess nitrogen and phosphorus don’t end up in stormwater and groundwater. What we do upstream on land ultimately ends up in the water and in us.
- Use an environmentally friendly service or self-service location when performing work on or washing your car.
