[ bahy-oh-uh-kyoo-myuh-ley-shuhn ]
/ ˌbaɪ oʊ əˌkyu myəˈleɪ ʃən /
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OTHER WORDS FROM bioaccumulation

bi·o·ac·cu·mu·la·tive, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does bioaccumulation mean?

Bioaccumulation is the continuous buildup of foreign substances, such as pesticides or toxic chemicals, within an organism.

Bio- is a prefix that means “life.” Accumulation means a continuous growing or collecting. The term bioaccumulation is short for biological accumulation.

Bioaccumulation is a scientific term that describes the buildup of (often harmful) substances in living organisms, such as animals and plants. The term is especially common in discussions of marine biology because aquatic life is particularly vulnerable to contamination from pesticides like DDT and toxins, such as mercury (when these things get into the water, they inevitably get into the animals and other organisms that live in the water).

This poses problems for individual organisms, but it’s also a problem for entire ecosystems. When the bioaccumulation in each organism is compounded (added together, or magnified), this is called biological magnification (or biomagnification). Biomagnification means that bioaccumulation can get worse for animals higher up in the food chain: the amount of toxic substances (such as mercury or pesticides) is greater in the bodies of organisms (including humans) that consume other organisms.

Why is bioaccumulation important?

In many cases, humans have had to learn the hard way that toxic chemicals can poison us without us even knowing it. Decades ago, dangerous substances like the pesticide DDT were commonly used with little to no safety regulations. Eventually, they got into bodies of water, and then into the fish living in those waters. Many people were unaware that the fish they ate for dinner could be loaded with DDT. Many dangerous chemicals like these have since been banned or regulated. But even now, decades later, some of these chemicals can be found in fish (and humans) thanks to the process known as bioaccumulation.

Bioaccumulation occurs when the level of a toxic foreign substance that has entered the body of a living organism gradually becomes more than the body can eliminate. The exact location of this buildup depends on what the intruding substance is and how it enters the body. Foreign substances can be absorbed through the skin or gills, breathed in from contaminated air, or ingested from contaminated food and drink. In order for bioaccumulation to happen, the amount of a toxic substance entering the organism must remain greater than the amount that is eliminated (by breathing it out or going to the bathroom, for example). For this reason, bioaccumulation is especially common in aquatic ecosystems like the ocean. While it is unlikely that a rabbit would continuously eat the same tainted plants over and over, it would be a lot harder for a fish to avoid large areas of contaminated water and the tainted food supply that it contains. Making things worse, the fatty tissue of fish is very good at storing absorbed or eaten chemicals.

The effects of bioaccumulation have only begun to be studied somewhat recently. Environmental and safety standards have become more strict over time and today many chemicals are thoroughly tested to avoid potential bioaccumulation in humans or animals. Many of the regulations enforced by government agencies such as the Environmental Protection Agency are also in place to prevent hazardous bioaccumulation that might happen due to pollution or illegal dumping of toxic materials.

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A modern example of bioaccumulation is the increasingly large number of fish being contaminated by mercury. Nutrition experts often warn against eating large amounts of fish known to be high in mercury, such as tuna and swordfish.

What are real-life examples of bioaccumulation?

Bioaccumulation is an important part of understanding how the food chain works. Because we can’t assume that a toxic substance will just go away, we need to be extra careful about what we eat and what kinds of things we put into the environment.

Bioaccumulation is most likely to appear in discussions of ecosystems and the environment, especially contaminated water and fish.


What other words are related to bioaccumulation?

Quiz yourself!

True or False?

Bioaccumulation occurs when an organism regularly takes in more of a substance, such as a toxin, than it can naturally eliminate.

Medical definitions for bioaccumulation

[ bī′ō-ə-kyōōm′yə-lāshən ]

The increase in the concentration of a substance, especially a contaminant, in an organism or in the food chain over time.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for bioaccumulation

[ bī′ō-ə-kyōōm′yə-lāshən ]

The accumulation of a substance, such as a toxic chemical, in various tissues of a living organism. Bioaccumulation takes place within an organism when the rate of intake of a substance is greater than the rate of excretion or metabolic transformation of that substance. Compare biomagnification.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.