APES Unit 8.7 Persistent Organic Pollutants (POPs)

Practice FRQ

★ Persistent organic pollutants (POPs), such as the

pesticide DDT and industrial chemicals like PCBs, have

been found in the fatty tissues of polar bears in the

Arctic and in the breast milk of indigenous populations

in remote northern regions—thousands of miles away

from where these chemicals were originally produced

or used.

(a) Identify one specific characteristic of POPs that allows them to

remain in the environment for long periods of time.

(b) Explain how the chemical properties of POPs lead to their high

concentration in the apex predators of an ecosystem.

(c) Scientists have observed high levels of POPs in Arctic regions,

despite these chemicals being banned in those areas for decades.

(d) Describe the physical process that allows POPs to travel from

warmer agricultural or industrial regions to the colder poles.

a) They have strong carbon bonds that are difficult to break apart.

b) POPs are fat soluble, meaning they easily accumulate into the fatty tissue of apex predators.

c) POPs break down for vastly long periods of time. As a result, they are carried by water and wind to far-flung places.

Chemical Persistence

How long chemical remains in enviroment

Chemical Persistence Factors

• Temperature

• Age

• Soil or Water

• Degraded by sunlight or microbes

Persistent Organic Pollutants

Synthetic carbon-based molecules that break down very slowly in the environment

• Fat-Soluble: Accumulate in fatty animal tissue

• Carried by wind and water for long periods of time

POPs Examples

• Pesticides: DDT

• Industrial compounds: PCBs, PFAs

• Dioxins

Industrial Chemicals PFAs

Synthetic organic chemicals used in nonstick pans, stain-resistant carpets, water-repelling clothing, food packaging, and fire retardants

• Carcinogens

• Weakened immune and reproductive systems

• “Forever chemicals”

Solutions to Lowering Persistent Organic Pollutants

1. Water Filtration: Fill in every home

2. Public Water Lines: Bring uncontaminated water to every home

• Expensive

Determinants of Chemical Concentrations in Organisms

• Route of Exposure

  • Air

  • Water (bathing, drinking, swimming)

  • Food

  • ex. Pesticides: Enter animals thru ingestion or sprayed droplets into permeable skin (amphibians > birds/mammals)

• Solubility of Chemical

  • High Solubility: Can wash off surfaces, percolate into groundwater, and run off into surface waters

  • Fat/Oil Solubility: Not soluble in water—

  • ex. Herbicides vs. Insecticides