BOD
Biological oxygen demand, amount of dissolved oxygen needed by aerobic decomposers to break down organic materials.
DDT
A powerful insecticide that is also poisonous to humans and animals and was banned in the 1970s due to its harmful environmental impact.
Fecal coliform
Bacteria that are found in excrement or sewage contamination occurring naturally in the digestive tract of human beings and animals that are used as an indicator of sewage contamination in water.
PCBs
Synthetic chemicals containing chlorine that are used in the manufacture of plastics and other industrial products and can accumulate in the tissue of animals and persist in the environment.