Mercury and PCBs are two types of harmful chemicals that may be found in Triangle-area lakes and rivers. These chemicals stay in the environment for many years and can build up in long-lived, predatory fish, like largemouth bass and catfish. The chemicals enter your body when you eat polluted fish.
Mercury and PCBs are odorless and colorless, so you can’t see, smell or taste these chemicals in fish.

How can mercury and PCBs affect my health?

Mercury and PCBs are especially dangerous for women ages 15 to 44 and for young children, who should avoid eating fish from polluted areas.

  • PCBs build up in the body and may cause cancer in humans.
  • Mercury builds up in the body and can harm the brain and kidneys.
  • Mothers can transfer PCBs and mercury to their unborn children during pregnancy and to an infant through breast milk.
  • Mercury and PCB exposure can harm the brain of a baby or young child.
  • Babies born to women who consume high levels of PCBs or mercury can have low birth weight.

Why are children at greater risk?

Children’s bodies are still developing and are smaller than adults. An amount of a chemical that would not harm an adult can cause damage to a child. Women, particularly those who are pregnant or thinking about becoming pregnant, should reduce their mercury and PCB exposure. Mercury accumulates in your blood and, although it is removed naturally, it can take over a year to decrease significantly.


Electric power generation and incinerators can put mercury into the air, where it falls directly into bodies of water or washes into lakes and rivers when it rains.

Across North Carolina, children and women ages 15-44 should never eat largemouth bass or other fish high in mercury caught in the state.

Southeast of I-85, catfish are also high in mercury and should never be eaten by children and women ages 15-44.


PCBs (polychlorinated biphenyls) have been found in and near Lake Crabtree as a result of pollution from the Ward Transformer Superfund site, located upstream from the lake near the Raleigh-Durham International Airport.

Ward Transformer was an industrial facility that manufactured, rebuilt and refurbished electrical transformers and other equipment from 1964 to 2006. PCBs leaked into the soil, surface water and groundwater during facility operations.

State fish advisories and local catch-and-release policies can help you choose which fish to eat.

For More Information

Agency for Toxic Substances and Disease Registry

ToxFAQ for Mercury | Mercury and Your Health | ToxFAQ for PCBs

Environmental Protection Agency

Mercury in Your Environment | Basic Information on PCBs | Health Effects of PCBs

NC Department of Health and Human Services

Fish Consumption Advisories