What is chemical persistence?

Persistence is usually described as the half-life (T ½) of a chemical in water, soil, sediment, or air. The T ½ is the amount of time necessary for a given amount of chemical released into the environment to decrease to one-half of its initial value.

What is bioaccumulation chemistry?

Bioaccumulation is a process of accumulation of chemicals in an organism that takes place if the rate of intake exceeds the rate of excretion. Chemicals are introduced into the organism through exposure to the abiotic environment (soil, water, air) or as dietary intake (trophic transfer).

What chemicals are found in bioaccumulation?

Chemicals such as PCBs, DDT, dioxins, and mercury are all persistent chemicals. Because they don’t break down and go away, these chemicals are a problem when it comes to fish that we eat. Especially when you consider that these chemicals can also bioaccumulate, or build up, in fish, wild game, and your body, too.

What is bioaccumulation example?

Examples of bioaccumulation and biomagnification include: Car emission chemicals building up in birds and other animals. Mercury building up in fish. Pesticides building up in small animals.

What does high persistence mean?

High persistence Children who are persistent will work hard to figure out exactly how that puzzle piece fits in, even if it is challenging. They will work very hard to finish something they have started and are likely to practice something they want master, like riding a bike.

What is toxic bioaccumulation?

Toxicology of Persistent Organic Pollutants Bioaccumulation occurs when the compound concentrates in living organisms or tissues. Bioaccumulation can counteract the effect of environmental dispersion and redistribute the chemical within the biosphere. POPs primarily accumulate in fatty tissues of the body.

Why are POPs toxic?

POPs pose a particular hazard because of four characteristics: they are toxic; they are persistent, resisting normal processes that break down contaminants; they accumulate in the body fat of people, marine mammals, and other animals and are passed from mother to fetus; and they can travel great distances on wind and …

What are persistent bioaccumulative and toxic substances?

From Wikipedia, the free encyclopedia Persistent, bioaccumulative and toxic substances (PBTs) are a class of compounds that have high resistance to degradation from abiotic and biotic factors, high mobility in the environment and high toxicity.

What is bioaccumulation in biology?

Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated by catabolism and excretion.

What is an example of bioaccumulative contamination?

For example, lead contamination of air, soil, or drinking water can ultimately result in significant exposures in fetuses, infants, and children, resulting in impaired brain development. Chemicals that accumulate in living organisms, so that their concentrations in body tissues continue to increase, are called bioaccumulative.

What are fat-soluble bioaccumulative chemicals?

Many bioaccumulative chemicals are fat-soluble so that they tend to reside primarily in fat deposits or in the fatty substances in blood. This explains why fat-soluble bioaccumulative chemicals are often found at elevated levels in fat-rich breast milk. [ 6]