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Bio Build-up

Author(s): Nancy Moreno, PhD, and Barbara Tharp, MS.

The Science of Bioaccumulation

In this activity, students observed the following properties of food.

  • Pollutants often are absorbed by organisms near the base of a food chain. These toxins usually are present in the water or soil in which producers (such as green plants and algae) or primary consumers (such as filter feeders in aquatic ecosystems) live and reproduce. 
  • Toxic chemicals can become concentrated in the bodies of consumers, especially those near the top of the food chain. Some chemical substances, such as pesticides and heavy metals (like mercury and lead), persist within the bodies of organisms that take them in with food. These compounds are not broken down by the body, nor are they eliminated with other waste products. Most of these substances are not harmful in trace amounts, but they can accumulate in the tissues of an organism over its lifetime. Consumers near the top of the food chain tend to accumulate larger amounts of toxic substances in their bodies, because pollutants become more concentrated at each step of the food chain.

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932