Water Pollutants

Sediment

Soil particles in bodies of water. 70% of sediment comes from human activities.

• Clear cutting, mining, and clearing land for development have all increased rates or erosion, creating sediment pollution

Issues:

• Blocks sunlight penetration, reducing productivity of algae and plants and reducing visibility of predators

• Clogs gills and prevents aquatic organisms from obtaining oxygen

Solid Waste (Trash)

Garbage thrown away by people

• Litter that reaches aquatic ecosystems (unsightly and creates intestinal blockage and choking hazards for wildlife and introduces toxic substances to the food chain

Thermal Pollution

Occurs when human activities cause a substantial change in the temperature of water

• A dramatic change in temperature can cause thermal shock, which is fatal to organisms

• Warm water holds less O₂

Noise Pollution

Sounds emitted by ships and submarines can interfere with animal communication

Especially loud sonar can negatively affect species such as whales that rely on low-frequency, long distance communication

Synthetic Compounds

Can enter water supply from industrial plant sources or from nonpoint sources when they are applied over large areas (farmland)

• Examples of synthetic compounds include pesticides and pharmaceuticals

Synthetic organic compounds can be toxic, persistent and cause genetic defects, and interfere with growth and sexual development

Oil

Petroleum products are highly toxic to many marine organisms

• Birds, mammals, and fish, as well as algae and microorganisms at the base of the aquatic food chain

Sources

• Drilling

• Oil spills from tankers

• Naturally (oil seeps)

Remediation of Oil

• Containment: booms keep the floating oil from spreading, then boats equipped with giant oil vacuums suck up as much oil as possible

• Dispersants: Chemicals break up oil on the surface, helping it dissolve before it reaches shore

• Bacteria: scientists are trying to optimize oil-degrading bacteria to break down spilled oil (bioremediation)

Heavy Metals

Neurotoxins, which affect nervous system function or development. Lead, arsenic, mercury

Lead

Found in pipes and other materials in older construction

Arsenic

Occurs naturally and through human activity such as mining and industry

Mercury

Occurs naturally and through human activity, primarily burning coal

Biological pollutants

Pathogenic microorganisms (bacteria and protists), which originate primarily from human and animal waste products

Pathogens can contaminate surface water as well as groundwater

Animal Feedlots and Manure Lagoons

Manure from concentrated animal feeding operations (CAFOs) may contain pathogens as well as hormones and antibiotics used on animals

Farmers may use manure lagoons (ponds lined with rubber) to store and decompose manure using bacteria

• Following decomposition, manure byproducts can be used as fertilizer