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

82% of the tidal Chesapeake Bay is partially or fully impaired by toxic contaminants

Pesticides, pharmaceuticals, metals, and other toxic contaminants can harm the health of humans and affect the survival, growth and reproduction of fish and wildlife. Found in sediment and the tissues of fish and other organisms, toxic contaminants enter the water through air pollution, agricultural runoff, stormwater runoff and wastewater. According to data submitted to the U.S. Environmental Protection Agency in 2016, 82 percent of the Chesapeake Bay’s tidal segments are partially or fully impaired by toxic contaminants. 

82

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

While chemical contamination is often seen as a localized problem occurring in “hot spots” or “regions of concern,” metals, polychlorinated biphenyls (PCBs) and priority organics exceed water quality criteria in at least part of all of the tidal tributaries that deliver water to the main stem of the Bay. A technical report shows 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 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 mercury-containing waste, as well as the improper disposal of old thermometers and other mercury-containing consumer products.

In the Chesapeake Bay Watershed Agreement, the Chesapeake Bay Program committed to increasing our understanding of toxic contaminants and improving the practices that prevent or reduce their effects on humans and the environment.

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.

491 million

The amount, in pounds, of nitrogen delivered to the Chesapeake Bay between October 2018 and September 2019

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. Generally, when the watershed receives more rain and river flows increase, the water carries more nitrogen, phosphorus and sediment pollution than usual, increasing loads received by the Bay. The U.S. Geological Survey (USGS) reports that between October 2018 and September 2019, river flow to the Bay measured an above-average 84.5 billion gallons per day, the highest recorded amount since 2011. According to our most recent water quality monitoring data, about 491 million pounds of nitrogen reached the Bay between October 2018 and September 2019: a 16% increase from the previous year. This is 40% higher than the long-term average annual load.

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.

34.8 million

The amount, in pounds, of phosphorus delivered to the Chesapeake Bay between October 2018 and September 2019

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. Generally, when the watershed receives more rain and river flows increase, the water carries more nitrogen, phosphorus and sediment pollution than usual, increasing loads received by the Bay. The U.S. Geological Survey (USGS) reports that between October 2018 and September 2019, river flow to the Bay measured an above-average 84.5 billion gallons per day, the highest recorded amount since 2011. According to our most recent water quality monitoring data, about 34.8 million pounds of phosphorus reached the Bay between October 2018 and September 2019: a 17% decrease from the previous year. This is 52% higher than the 1985-2019 long-term average.

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.

26.6 billion

The amount, in tons, of sediment delivered to the Chesapeake Bay between October 2018 and September 2019

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. Generally, when the watershed receives more rain and river flows increase, the water carries more nitrogen, phosphorus and sediment pollution than usual, increasing loads received by the Bay. The U.S. Geological Survey (USGS) reports that between October 2018 and September 2019, river flow to the Bay measured an above-average 84.5 billion gallons per day, the highest recorded amount since 2011. According to our most recent water quality monitoring data, about 26.6 billion tons of sediment reached the Bay between October 2018 and September 2019, a decrease from the previous year. Experts suggest the decline in sediment could be a result of management actions on controlling nonpoint source pollution in the Bay watershed. For the long term, this is 25% higher than the 1985-2019 long-term average annual load.