Chapter 21 Jesus Ramirez Jake McCleery

eutrophication Physical, chemical, and biological changes that take place after a lake, estuary, or slow-flowing stream receives inputs of plant nutrients mostly nitrates and phosphates from natural erosion and runoff from the surrounding land basin. See cultural eutrophication.

What pollutes water, where do these pollutants come from, and what effects they have? Water is polluted by disease-causing agents, oxygen demanding wastes, plant nutrients, organic and inorganic chemicals, sediment, and excess heat.

nonpoint source Large or dispersed land areas such as crop fields, streets, and lawns that discharge pollutants into the environment over a large area. Compare point source. point source Single identifiable source that discharges pollutants into the environment. Examples are the smokestack of a power plant or an industrial plant, drainpipe of a meatpacking plant, chimney of a house, or exhaust pipe of an automobile. Compare nonpoint source.

oxygen-demanding wastes Organic materials that are usually biodegraded by aerobic (oxygen-consuming) bacteria if there is enough dissolved oxygen in the water. See also biological oxygen demand.

primary sewage treatment Single identifiable source that discharges pollutants into the environment. Examples are the smokestack of a power plant or an industrial plant, drainpipe of a meatpacking plant, chimney of a house, or exhaust pipe of an automobile. Compare nonpoint source

What are the major water pollution problems in streams and lakes? Factory waste, untreated sewage waste

primary sewage treatment Mechanical sewage treatment in which large solids are filtered out by screens and suspended solids settle out as sludge in a sedimentation tank. Compare advanced sewage treatment, secondary sewage treatment. septic tank Underground tank for treating wastewater from a home in rural and suburban areas. Bacteria in the tank decompose organic wastes, and the sludge settles to the bottom of the tank. The effluent flows out of the tank into the ground through a field of drainpipes.

What causes groundwater pollution, and how can it be prevented? Groundwater can become contaminated with a variety of chemicals because it cannot effectively cleanse itself and dilute and disperse pollutants. Better monitoring of underground gas tanks Prevent oil spills. Better testing for aquifers.

Sludge Gooey mixture of toxic chemicals, infectious agents, and settled solids removed from wastewater at a sewage treatment plant. tertiary (higher-level) consumers Animals that feed on animal-eating animals. They feed at high trophic levels in food chains and webs. Examples are hawks, lions, bass, and sharks. Compare detritivore, primary consumer, secondary consumer

What are the major water pollution problems affecting oceans? Pollution in the ocean directly affects ocean organisms and indirectly affects human health and resources. Oil spills, toxic wastes, and dumping of other harmful materials are all major sources of pollution in the ocean. People should learn more about these because if people know more about pollution in the ocean, then they will know more about how to stop pollution.

How safe is drinking water, and how can it be made safer? Water treatment plants and watershed protection can provide countries. Simpler and cheaper ways can be used to purify drinking water for individuals and villages in developing countries.

tertiary sewage treatment A process for purification of wastewater in which nitrates and phosphates, as well as fine particles, are removed; the process follows removal of raw sludge and biological treatment. Also known as advanced sewage treatment. water pollution Any physical or chemical change in surface water or groundwater that can harm living organisms or make water unfit for certain uses.