25-37 DDTs & POPs

APES 2024

Eutrophication

Eutrophication

A phenomenon in which a body of water
becomes rich in nutrients

Cultural eutrophication

An increase in fertility in a body of water, the result of anthropogenic inputs of nutrients

Eutrophication sources

• Discharge from sewage treatment plant – has nitrogen and phosphorous

• Animal waste from large farms

• Synthetic fertilizer added to farms

Oligotrophic waters

low amounts of nutrients, stable algae populations and high dissolved oxygen

Oligotrophic waters causes

lack of nutrient pollution or age of body of water

Oligotrophic waters effects

• Aquatic ecosystem will undergo succession

• Sediment builds up on bottom and leads to more nutrients

• Over time the pond shifts from oligotrophic to eutrophic naturally

Bioaccumulation

absorption and concentration of elements or compounds by cells in a living organism, most commonly fat-soluble compounds (organism)

Biomagnification

increase in chemical concentration of substances per unit of body tissue that occurs in successively higher trophic levels in a food chain or web

Some effect that can occur when a persistent substance is biomagnified in a food chain includes

eggshell thinning and developmental deformities in top carnivores in the higher trophic levels (DDT)

DDT causes

• near extinction of peregrine falcons and bald eagles

• Humans can experience issues with reproductive, nervous, and circulatory system
  (Pregnant women encouraged to not eat fish with mercury in it)

Endocrine disruptors effects

• Interfere with the endocrine system of animals

• Impacts growth, metabolism and development of reproductive organs

• Chemicals mimic the hormones in the body and bind to receptor cells and cause a response that is harmful

Wastewater can have hormones from

farms, birth control pills, and pesticides

Human medicine that passes through urine into sewage or flushed down toilet are a

common sources of endocrine disruptors

Male fish, reptiles and amphibians are becoming feminized due to high levels of estrogen caused by

atrazine binds to receptors that should convert estrogen to testosterone

Male fish/reptile/amphibian feminization causes

• Low sperm counts

• Testes that produce both sperms and eggs

• Birth defects, developmental disorders and gender imbalances

BPA causes cancer, nerve damage, and miscarriages in

extremely low doses

BPA was in

cans, utensils, baby bottles, laptops, toys (banned in baby bottles and sippy cups in 2012 in US)

BPA leaches into food, water, air, and bodies causing

93% of Americans have it in their bodies

insecticide that was phased out but still persists and was applied to agricultural fields, and runoff to surface and groundwater

DDT

Phthalates

compounds used in plastic and cosmetic manufacturing

• Enter surface and groundwater by trash dumping or waste from factories
  improper dumping of waste

• Found in some cosmetics and plastic food containers

Phthalates

Persistent Organic Pollutants (POPs)

• do not easily break down in the environment

• Synthetic, carbon-based molecules

• Ex. DDT and PCBs

• Can be toxic to organisms because they are soluble in fat

• Accumulates in organism’s fatty tissues (liver)

• Can travel long distances over water and wind and be redeposited

In the 1960s, untested pesticides were sprayed over
public areas, with assumption

they would do no harm

showed DDT’s risks to people, wildlife, and ecosystems

Rachel Carson’s Silent Spring (1962)

Chemical companies challenged the book and tried to discredit Carson’s personal reputation

True

DDT was banned in the U.S. but

is still made in the U.S. and exported