How does pollution happen?
Most of the pollutants that we are concerned about in North Carolina’s freshwater fish come from human-made pollution that is released to air, water, or soil and which ends up in our waterbodies. Even air pollutants eventually make their way back down to lakes and rivers through rain, snow, and settling dust particles.
So what? Once chemical pollutants get into our water, they are taken up by smaller organisms at the bottom of the food chain like algae and insects, which are eaten by small fish, which are then eaten by larger fish, and so on up the food chain until the largest fish is eaten by a human. This process of increasing levels of pollutants with each step in the food chain is called biomagnification. So as you move up the food chain, those larger, predatory fish that people like to eat the most often have higher amounts of chemicals in their bodies. It is almost always better to choose smaller-sized fish when trying to reduce exposure to chemicals.
What pollutants are we worried about in North Carolina?
Mercury – a naturally-occurring metal found in the earth’s crust that is released to the environment through volcanic activity or when humans mine for ore and burn coal to produce electricity.
Polychlorinated Biphenyls– a group of 209 related compounds that were used in industrial applications until they were banned in the 1970s, but continue to be present in the environment today.
Dioxins– a group of related chemicals that last for a long time once they enter the environment, mostly from industrial contamination.