Pollution

When pollutants like excess nutrients, sediment and chemical contaminants enter local waterways, they threaten the health of plants and animals that live in the Bay ecosystem.

Toxic Contaminants

Pesticides, pharmaceuticals, metals and other toxic contaminants can harm the health of humans and wildlife. Found in sediment and the tissues of fish and other organisms, these contaminants enter the water through air pollution, agricultural runoff, stormwater runoff and wastewater. In the Chesapeake Bay Watershed Agreement, the Chesapeake Bay Program committed to increasing our understanding of the impacts and mitigation of toxic contaminants and improving the practices that prevent or reduce the effects of these contaminants on humans and the environment.

74

The percentage of the Chesapeake Bay's tidal waters that are partially or fully impaired by toxic contaminants

According to data submitted to the U.S. Environmental Protection Agency in 2012, 74 percent of the Chesapeake Bay’s tidal waters are partially or fully impaired by toxic contaminants. A technical report shows polychlorinated biphenyls (PCBs) and mercury are particularly problematic in the region, and are considered widespread in severity and extent.

While PCBs have not been manufactured in the United States since a 1979 ban, the chemicals can be found in old electrical equipment, paint, plastics and other products, and continue to enter the environment through accidental leaks, the improper disposal of PCB-containing consumer products and "legacy deposits." Mercury is released into the environment through the burning of coal, oil and wood as fuel, as well as the burning of waste that contains mercury and the improper disposal of old thermometers and other mercury-containing consumer products.

Polycyclic aromatic hydrocarbons (which form when gas, coal and oil are burned) and some herbicides (which are used to control weeds) are also considered widespread, while dioxins, petroleum hydrocarbons, some chlorinated insecticides and some metals occur locally. We do not have enough information to determine the extent of biogenic hormones, household and personal care products, pharmaceuticals or flame retardants in our waterways.

Nitrogen Pollution

While plants and animals need nutrients to survive, excess nutrients can fuel the growth of algae blooms that lead to low-oxygen “dead zones” harmful to underwater life. In the Chesapeake Bay Watershed Agreement, the Chesapeake Bay Program set a goal to reduce nitrogen and other pollutants and improve water quality.

334 million

The average amount, in pounds, of nitrogen delivered to the Chesapeake Bay each year

The amount of nitrogen entering the Chesapeake Bay can change dramatically from year to year and is influenced by land use, land management and river flow. According to our most recent water quality monitoring data, approximately 217 million pounds of nitrogen reached the Bay between October 2014 and September 2015: a 25 percent drop from the previous year. This is below the long-term average annual load of 334 million pounds.

Phosphorus Pollution

Like nitrogen, phosphorus is also a nutrient of concern in the region. In the Chesapeake Bay Watershed Agreement, the Chesapeake Bay Program set a goal to reduce phosphorus and other pollutants and improve water quality.

20 million

The average amount, in pounds, of phosphorus delivered to the Chesapeake Bay each year

The amount of phosphorus entering the Chesapeake Bay can change dramatically from year to year and is influenced by land use, land management and river flow. According to our most recent water quality monitoring data, approximately 9.8 million pounds of phosphorus reached the Bay between October 2014 and September 2015: a 44 percent drop from the previous year. This is below the long-term average annual load of 20 million pounds.

Sediment Pollution

Loose particles of sand, silt and clay are a natural part of the Chesapeake Bay ecosystem. But sediment in excess amounts can cloud the water and harm underwater grasses, fish and shellfish. In the Chesapeake Bay Watershed Agreement, the Chesapeake Bay Program set a goal to reduce sediment and other pollutants and improve water quality.

5 million

The average amount, in tons, of sediment delivered to the Chesapeake Bay each year

The amount of sediment entering the Bay can change dramatically from year to year and is influenced by land use, land management and river flow. According to our most recent water quality monitoring data, approximately 1.5 million tons of sediment reached the Bay between October 2014 and September 2015: a 59 percent drop from the previous year. This is below the long-term average annual load of 5.32 million tons.