Water Pollution Flashcards
Measurements of the level of pollutants in water.
Water Quality
Measurements of the amount of water.
Water Quantity
Pollution that is released from a widespread area, making it more challenging to control.
Non-point Source Pollution
Pollution that is released from a specific location, such as a pipe or a smokestack.
Point Source Pollution
Acid Deposition
AKA, acid rain (or acid snow): Precipitation with a low pH.
Sources of Acid Deposition
Power plants, cars, and factories that release nitrous oxides and / or sulfur oxides into the air. These combine with water vapor to form nitric acid or sulfuric acid.
Impacts of Acid Deposition
Small aquatic organisms and fish eggs can be killed directly by the low pH. Larger organisms may slowly starve as the food web collapses below them. Trees may have damaged leaves. Statues and buildings made of limestone or marble slowly break down by the chemical reaction with acid.
Algae Bloom
The overgrowth of phytoplankton in a body of water.
Sources of algae blooms.
Eutrophication - adding nutrients to the water. These nutrients include nitrates and phosphates, which can come from fertilizers (from agricultural fields, golf courses, and lawns), animal waste (from feedlots or pets), and human sewage. Treated sewage often still contains nutrients, which are left behind when the wastes are broken down.
Impacts of algae blooms.
The water can become murky and smelly. As the algae overpopulate, many cells complete their short life cycles, resulting in a build-up of dead algae in the water. Decomposing bacteria use up oxygen from the water, as well as releasing foul odors. The low levels of dissolved oxygen can harm fish and other organisms.
A process where an animal ingests toxic molecules, and the toxins are stored in the animal’s fatty tissues.
Bioaccumulation
A process where the concentration of a toxin increases at higher levels of the food chain. As predators consume many prey organisms, the toxins in the prey reach higher dosages in the predator. As a result, predators may be more harmed by the toxin than their prey.
Biomagnification
D.O.
The amount of oxygen used by decomposing bacteria to break down organic materials. As this value increases, the oxygen levels drop, which can harm fish and other organisms.
Biological Oxygen Demand (or biochemical oxygen demand): B.O.D.
A graph of the oxygen content of a river as it flows past a point source of pollution. The graph shows a rapid drop in D.O. at the point source, followed by a slow recovery.
Oxygen Sag Curve - the D.O. graph “sags” at the point source, then bounces back downstream.
Describe the changes in B.O.D. across an oxygen sag curve.
Upstream from the point source of pollution, BOD is low. When the river reaches the source of pollution, BOD jumps. As the river flows away from the pollutants, BOD gradually drops back to its normal low levels.
Describe the changes in aquatic organisms across an oxygen sag curve.
Trout, mayflies, and other sensitive organisms that need high D.O. thrive upstream from the point source of pollution. These organisms either die off or swim away from the pollution due to the low oxygen levels. Instead, tolerant species like carp and leeches dominate the zone of low oxygen. If the oxygen drops far enough, no fish survive. Further downstream, where the river has recovered, trout and mayflies can be found again.
A synthetic pesticide that was banned in the US due to its impact on the reproductive system. It is known to have caused eggshell-thinning in birds that prey on fish.
DDT (Dichlorodiphenyltrichloroethane)
Sources and History of DDT
DDT was invented in the late 1800s and was commonly used to kill insects after WWII. It was primarily used in agriculture, along with mosquito control. It’s use was banned in the US in 1972. Today it is still used in some countries, mostly to control mosquitos that spread malaria.
Impacts of DDT
DDT interferes with the reproductive system. In piscivorous birds (fish eaters), it bioaccumulates and biomagnifies. This results in egg-shell thinning, which kills the chicks before they hatch.
A location in the ocean where very few organisms live. It is usually near the mouth of a river that drops off a variety of pollutants, and oxygen levels are often low.
Dead Zone
A toxic molecule released by several industrial processes, such as bleaching. It can cause cancer.
Dioxin
Molecules that can either mimic or block the action of hormones.
Endocrine Disruptors