What happens when humans introduce chemicals into the environment? Warmup- Symbiosis Worksheet Get out Homework and turn it in!! Essential Question- What happens when humans introduce chemicals into the environment?

Bioaccumulation & Biomagnification Chemicals in our Environment

Bioaccumulation The gradual buildup, over time, of a chemical in a LIVING ORGANISIM

Depicted here is a representation of bioaccumulation in a Northern ecosystem. Northern populations may be uniquely susceptible to bioaccumulation of certain toxicants because of their culture, lifestyle and diet. Diets high in animal fats, particularly meat and blubber from seal, walrus, whale as well as fish and birds may contribute to the accumulation of chemicals such as organochlorines in humans. In women, organochlorines derived from the diet are accumulated in fat stores and are subsequently secreted in breast milk and fed to nursing infants. Detectable levels of many chemicals have been found in breast milk, serum, hair and fingernails. These studies have led to the development of health advisories which, through alterations of dietary practices, hope to reduce the levels of chemical contamination in humans.

Why Does This Happen? Chemicals are taken up faster than they are used Or Chemicals can’t be broken down by the organism for use - can’t get rid of chemicals bc they get suck in “adipose” tissue

Pollutants Chemical pollutants that are bioaccumulated come from many sources Pesticides Industrial Smoke Stacks Automobile Emissions Deliberate Discharge of Compounds into Water

Soil(10ppm)Earthworms(141ppm)Robins(444ppm) Biomagnification The buildup of substances by successive trophic levels Example: A predator will have higher concentrations of a chemical compared to its prey DDT Soil(10ppm)Earthworms(141ppm)Robins(444ppm)

i.e. mercury in salmon

24 units 12 units 6 units 2 units 1 unit

DDT Dicholoro-diphenyl-trichloroethane An insecticide used in the 40’s, 50’s and 60’s entered the environment in run-off from land Was banned in 1972 after the Bald Eagle population had a noticeable crash. - DDT affected reproduction of fish eating birds - banned in 1970s

What is the difference Biomagnification Bioaccumulation