AP Environmental Science · Unit 8 Aquatic/Terrestrial Pollution
Learning Objectives
Trace Toxin: A fat-soluble pollutant (like DDT or Mercury) enters the water at extremely low, seemingly harmless levels.
Bioaccumulation: Plankton absorb the toxin over their lifetime. Because it is fat-soluble, it cannot be excreted. It builds up inside the organism.
Biomagnification: A small fish eats 1,000 plankton, taking in ALL their toxin. A large fish eats 1,000 small fish. An Eagle eats 100 large fish. The concentration multiplies exponentially.
Tags
DDTMercuryFood ChainTrophic Scale
TOXIN CONCENTRATION (ppm)
Trophic Level Mechanics
Conc. at Trophic Lvl = (Initial Conc.) × (10% Rule Loss Factor)⁻¹
Water Base: The system starts with an ultra-dilute trace amount of DDT in the water (0.000003 ppm).
AP Exam Tip
You must know the difference between the two terms! Bioaccumulation happens within ONE individual organism over its lifetime. Biomagnification happens ACROSS multiple trophic levels in a food chain. It is the reason Bald Eagles almost went extinct (thin eggshells from massive DDT doses).