notes for water pollution Environmental Geology Chapter 14WATER POLLUTION • Water Pollution is degradation of water quality as measured by biological, chemical, or physical criteria ….. Based on: – Intended use – Departure from chemical or physical norm – Public health/ecological impacts • Pollutants are any substances that, in excess, are known to be harmful to living organisms. • Common Pollutants • Oxygen-demanding waste (common organic waste) • Pathogenic waste (pathogenic microbes) • Nutrients • Petroleum (oil) • Toxic waste (chemicals, heavy metals, radioactive waste) • Sediment • Thermal plumes • Oxygen-demanding waste – Dead organic matter decomposed by bacteria, which needs Oxygen – BOD: High BOD associated with a high level of decaying organic matter in water, reducing O for other healthy organisms – Sources of oxygen-demanding waste: Natural processes, agricultural applications, urban sewage, and runoff • Pathogenic microbes – Fecal coliform bacteria – Harmful risks (diseases and death ) of E. coli – Billions exposed to waterborne diseases, especially in poor countries – Outbreaks do occur in developed countries, e.g., 400,000 cases in WI, 1993 – Epidemic risks of waterborne diseases during natural disasters • Common harmful microorganisms: E. coli, Giardia & Cryptosporidium • North Carolina “Hog-saster” caused by pathogenic microbes-fecal coliform bacteria – Massive number of hog farms in coastal N.C. – Minimally regulated waste disposal practices ° Unlined waste ponds widespread – Area is low, flat, coastal floodplain – Hog farm sizes in North Carolina grew by 500% during the early and mid-1990s– Expansion largely due to lax regulations on location and waste disposal practices – Many facilities located themselves in flood-prone areas along the NC coastal plain – Subject to periodic heavy rains from nor’easters and hurricanes – Hurricane Floyd dropped up to 20 inches of rain on the area in 1999 – Many waste ponds were overtopped and/or breached, leading to MASSIVE surface water contamination with hog waste – Many people and animals adversely affected – Hurricane Floyd destroyed many of these farms and spilled 1 million tons of hog waste products into rivers and other bodies of water throughout the area – Ecological disaster occurred, killing fish, plants and becoming a hazardous nuisance to human residents throughout the area as well – Similar, though smaller scale, incidents related to release of hog waste have killed fish in streams in MO and IA • Nutrients – Two important nutrients: N, P – Major problems: Cultural eutrophication—algae bloom, triggering BOD problem -Too much oxygen demanding waste can lead to increases in algae and a lowering of oxygen content in the water “Dead Zones” can be created. For example: There is a Dead Zone at depth in bottom water –Gulf of Mexico-near shore, and on the Island of Maui there are algal buildup problems due to excess nutrients from wastewater and agricultural runoff. – Major sources for nutrients: Fertilizer, feedlots, and discharge from wastewater treatment plants • Eutrophication (overabundance/”bloom” in algae, etc.) Red tides/rivers “turn to blood” • Oil – Major problems: Polluted water, ecosystem damage, interrupted socioeconomic conditions of a community – Major sources: Oil spills from tankers and pipelines, on- or offshore oil production, war (e.g., Gulf War) • Toxic waste Ø Hazardous chemicals, e.g., Love Canal, MTBE, TCE, Benzene, Dioxin, etc. Ø Heavy Metals: Pb, Hg, Zn, Cd Ø Biomagnification of methyl mercury in aquatic organisms ((e.g. fish) – Predator fish accumulate more from consuming other fish (to a dangerous level)) ØØ Radioactive materials • Sediment pollution - a resource “out of place” Ø Sand and smaller particles Ø Polluted streams, lakes, reservoirs, even ocean water Ø Major sources: Soil erosion, dust storms, floods, and mudflows Ø Greatest pollutant by volume • Thermal pollution Ø Temp increases, less dissolved oxygen Ø Adverse changes to the habitats of organisms Ø Economic impacts Ø Major sources: Hot-water discharge from industrial operations, power plants, “abnormal” ocean currents • Surface Water Pollution and Treatment • Point sources of pollution Ø Point sources are discrete, confined, and more readily identifiable Ø Common sources: Landfills, discharge from wastewater treatment plants, discharge from industries, power plants, storm water runoff, etc. Ø Identify sources, on-site treatment and mitigation, prevention • Non-point sources of pollution Ø Non-point sources are diffused, intermittent, and hard to specifically identify Ø Causes of non-point pollutions often regional, cumulative and compound Ø Examples: u Run-off from streets and fields u Acid mine/tailings drainage – Sulfide minerals produce sulfuric acid in presence of oxygenated surface waters and microbes – pH’s of
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