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 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 2014, 80 percent of the Chesapeake Bay’s tidal segments are partially or fully impaired by toxic contaminants.

80

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.

331 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, about 241 million pounds of nitrogen reached the Bay between October 2015 and September 2016: a 12 percent increase from the previous year. This is below the long-term average annual load of 331 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, about 13.6 million pounds of phosphorus reached the Bay between October 2015 and September 2016: a 35 percent increase from the previous year. This is below the long-term average annual load of 19.8 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, about 2.5 million tons of sediment reached the Bay between October 2015 and September 2016: a 58 percent increase from the previous year. This is below the long-term average annual load of 4.9 million tons.