Earth Science

Human Impacts on the Earth Environment

Mercury Pollution

Study Tip
Coal naturally has traces of mercury in it. Half of mercury emissions come from power plants, but installing pollution-control devices can prevent this.

Pollution in the Atmosphere

Burning coal releases mercury into the atmosphere. Breathing in mercury isn’t harmful, but ingesting it is. Mercury condenses into methyl-mercury, which then deposited into water.

Study Tip
Coal naturally has traces of mercury in it. Half of mercury emissions come from power plants, but installing pollution-control devices can prevent this.

Bioaccumulation

Bioaccumulation in aquatic animals is when pollutants they’ve ingested continue to remain in their bodies. As more and more mercury is accumulated going up the food chain, bigger fish are left with the most amount of this chemical in their bodies. Therefore, we can’t eat certain types of fish (such as tuna) frequently, because they contain so much mercury that it will be harmful to us.

Human Damage

Methyl-mercury poisoning can cause brain damage and developmental delays. It also is stored in the fat women develop when they’re pregnant or nursing, causing harm to their babies.

The amount of mercury in a fish
The amount of mercury in a fish increases as the food chain progresses.
Concept Check
  • How does mercury pollute the atmosphere? What does mercury become when it gets deposited into water?
  • What is bioaccumulation? Why can’t we eat certain kinds of fish frequently?
  • What are the effects of methyl-mercury poisoning on humans?