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2.3 – Effect of Bioaccumulation on Ecosystems

2.3 – Effect of Bioaccumulation on Ecosystems. Role of Amphibians. live on both land and in the water. sensitive to chemical changes in the environment Since the 1980s, many amphibian species have suffered declines in population. alarming increases in amphibian birth deformities.

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2.3 – Effect of Bioaccumulation on Ecosystems

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  1. 2.3 – Effect of Bioaccumulation on Ecosystems

  2. Role of Amphibians • live on both land and in the water. • sensitive to chemical changes in the environment • Since the 1980s, many amphibian species have suffered declines in population. • alarming increases in amphibian birth deformities. • Many theories attempt to explain these changes, including drought, increased UV rays, pollution, habitat loss, parasites, and diseases.

  3. Pollutants and the Food Chain Human activities can make natural disturbances much worse Introduced synthetic (human made) chemicals into the environment

  4. What is Bioaccumulation? Bioaccumulation: gradual build-up of chemicals in living organisms Occurs when chemicals are taken up/stored faster than they can be broken down/excreted Absorbed through food, skin contact, or respiration

  5. Chemicals can affect the nervous, immune, and reproductive systems in animals • Ex. birth defects, inability to reproduce • Keystone Species: species that can greatly affect population numbers and an ecosystem’s health

  6. Salmon Food source for bears, wolves, eagles, etc. Source of nutrients as they decay

  7. What is Biomagnification? Biomagnification: chemical that accumulate AND become more concentrated at each trophic level chemicals are passed on as they are eaten and digested

  8. Red Tides Produce toxic chemicals that affect clams, mussels, and oysters Toxins bioaccumulate to a level that is poisonous for larger animals

  9. PCB’s and Orcas • PCB: polychlorinated biphenyls • Synthetic chemicals used from the 30s-70s in industrial products • Have long half-lives (the amount of time it takes to decay) • Affects reproduction in orcas • May last until 2030 • Newborn calves have high levels of PCBs, even though they’ve been banned for decades

  10. Persistent Organic Pollutants • Persistent Organic Pollutants (POPs): carbon-containing compounds that remain in water and soil for many years • Includes PCBs • Ex. insecticide sprays

  11. DDT (dichlorodiphenyltrichloroethane): meant to control mosquitoes Banned because of biomagnification, long half-life, and presence in environment Accumulation measured in parts per million (ppm) 1 ppm = 1 particle mixed with 999,999 other particles DDT toxic at 5ppm

  12. Heavy Metals • Metallic elements with a high density that are toxic at low concentrations • Don’t degrade and can’t be destroyed • Some are essential to the human body in small quantities • Copper • Zinc 3 of the worst heavy metals are lead, cadmium, and mercury!

  13. Lead Naturally present in all soils but levels have increased Used in insecticides, paints, and gas; now found in electronics not considered safe at ANY level Can be ingested, absorbed, or inhaled Can cause anemia, nervous system damage, reproduction difficulties, and impaired mental development

  14. Cadmium • Found in the Earth’s crust • Released through weathering, volcanoes, and forest fires • Used in plastics manufacturing and rechargeable batteries • Enters soil through zinc production and phosphate ore mining • Toxic to earthworms and negatively impacts fish (higher death rates, lower reproduction rates)

  15. Major source of Cadmium poisoning: SMOKING (tobacco absorbs it) • Causes lung cancer • Moves through the digestive system  liver  kidneys • Leads to infertility and damage to the central nervous system, immune system and DNA

  16. Mercury • Released naturally (volcanoes, weathering, etc.) • Levels dramatically increased due to fossil fuels, mining, industrial uses (batteries), etc. • Coal burning accounts for 40 percent of the mercury released into the atmosphere. • Falls as rain and dust, then binds to soil

  17. Mercury bioaccumulates in the brain, heart and kidneys of many animals

  18. Reducing the Effects of Chemical Pollution Method 1: Trap contaminant in soil • Example: phosphate fertilizer is added to lead contaminated soil • By trapping chemicals in the soil, they cannot enter the food chains as easily Method 2: Bioremediation • the use of micro-organisms or plants to help clean up toxic chemicals • Example: the oil industry uses bacteria to “eat” oil spills

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