Water+Pollution

Water Pollution Sources: -Geology of aquifers from which groundwater is abstracted -Industrial discharge of chemical wastes and byproducts -Discharge of poorly treated or untreated sewage -Surface runoff containing pesticides or fertilizers -Slash and burn farming practice, which is often an element within shifting cultivation agricultural systems -Surface runoff containing spilled petroleum products -Surface runoff from construction sites, farms, or paved and other impervious surfaces e.g. silt -Discharge of contaminated and/or heated water used for industrial processes, -Acid rain caused by industrial discharge of sulphur dioxide (by burning high-sulphur fossil fuels) -Excess nutrients are added (eutrophication) by runoff containing detergents or fertilizers -Underground storage tank leakage, leading to soil contamination, and hence aquifer contamination -Inappropriate disposal of various solid wastes and, on a localized scale, littering -Oil spills Contaminants: (Contaminants may include organic and inorganic substances) Organic-Insecticides and herbicides, a huge range of organohalide and other chemicals, Bacteria, often is from sewage or livestock operations, Food processing waste, Tree and brush debris from logging operations, VOCs (Volatile organic compounds), such as industrial solvents, from improper storage, Petroleum Hydrocarbons including fuels (gasoline, diesel, jet fuels, and fuel oils) and lubricants (motor oil) from oil field operations, refineries, pipelines, retail service station's underground storage tanks, and transfer operations. Note: VOCs include gasoline-range hydrocarbons. Inorganic- Heavy metals including acid mine drainage, Acidity caused by industrial discharges (especially sulfur dioxide from power plants), Pre-production industrial raw resin pellets, an industrial pollutant, Chemical waste as industrial by products, Fertilizers, in runoff from agriculture including nitrates and phosphates, Silt in surface runoff from construction sites, logging, slash and bum practices or land clearing sites Transport and chemical reactions of water pollutants: -Most water pollutants are eventually carried by the rivers into the oceans. In some areas of the world the influence can be traced hundred miles from the mouth by studies using hydrology transport models. Advanced computer models such as SWMM or the DSSAM Model have been used in many locations worldwide to examine the fate of pollutants in aquatic systems. -Indicator filter feeding species such as copepods have also been used to study pollutant fates -Areas of oxygen depletion are caused by chemicals using up oxygen and by algae blooms, caused by excess nutrients from algal cell death and decomposition. Fish and shellfish kills have been reported, because toxins climb the food chain after small fish consume copepods, then large fish eat smaller fish, etc. Each successive step up the food chain causes a stepwise concentration of pollutants such as heavy metals (e.g. mercury) and persistent organic pollutants such as DDT. This is known as biomagnification or bioaccumulation -The big gyres in the oceans trap floating plastic debris. -Many chemicals undergo reactive decay or chemically change especially over long periods of time in groundwater reservoirs. -Groundwater pollution is much more difficult to abate than surface pollution because groundwater can move great distances through unseen aquifers. Secondary effects: 1) Silt bearing surface runoff from can inhibit the penetration of sunlight through the water column, hampering photosynthesis in aquatic plants, and 2) Thermal pollution can induce fish kills and invasion by new thermophyllic species Regulation/Laws/Acts: State anti-pollution laws and federal legislation enacted in 1899; the Refuse Act of the federal Rivers and Harbors Act of 1899 prohibits the disposal of any refuse matter from into either the nation's navigable rivers, lakes, streams, and other navigable bodies of water, or any tributary to such waters, unless one has first obtained a permit; The Water Pollution Control Act, passed in 1948, gave authority to the Surgeon General to reduce water pollution; Federal Water Pollution Control Act Amendments of 1972 (Clean Water Act) established the basic mechanisms for regulating contaminant discharge and the authority for the US EPA to implement wastewater standards for industry, also continued requirements to set water quality standards for all contaminants in surface waters.