Water pollution
From Freepedia
Water pollution has many sources and characteristics. Humans and other organisms produce bodily wastes which enter rivers, lakes, oceans and other surface waters; in high concentrations these wastes result in bacterial contamination and excessive nutrient loading (eutrophication). Industries discharge a variety of compounds such as heavy metals, and wastewater, sometimes in toxic concentrations, from industrial process may also be too hot or too low in dissolved oxygen to support life. Silt-bearing runoff from construction sites and farms can inhibit the penetration of sunlight through the water column, hampering water organisms in their ability to photosynthesize.
Groundwater pollution is more difficult to clean up than surface pollution because groundwater can move hundreds of miles through unseen aquifers. Porous, fine-grained aquifers such as sands and sandstones naturally purify water of bacteria by simple filtration (adsorption and absorption), dilution, and, to a lesser extent, chemical reactions and biological activity. Groundwater that moves through cracks and caverns is not filtered and can be polluted just as easily as surface water. In fact this can be aggravated by the human tendency to use sinkholes in areas of Karst topography as dumps.
Contents |
Causes
Image:Terminalkils2.jpg The causes of water pollution can be divided into two groups: anthropogenic sources of pollution are those due to human choices, and natural sources are those resulting from forces intrinsic to the environment.
Anthropogenic sources include:
- discharge of poorly-treated or untreated sewage;
- 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 sulfur dioxide (by burning high-sulfur fossil fuels)
- excess nutrients added by runoff containing large amounts of detergents or fertilizers
Natural sources include:
- seasonal turnover of lakes and embayments;
- siltation due to floods;
- eutrophication of lakes due to seasonal changes
- acid rain caused by natural volcanic discharges or smog from factories
- acid pollution of rivers and lakes by runoff from naturally acid soils
- carbon dioxide discharges and runoff, volcanic or mineral
Contaminants
Contaminants may include organic and inorganic substances. Organic water pollutants include:
- bacteria,that is from sewage or livestock operations;
- fertilizers, in runoff from agricultural fields or forestry;
- food processing waste;
- tree and brush debris from logging operations
Inorganic pollutants include:
- metals
- acid mine drainage
- acid rain caused by industrial or volcanic discharges
- acid pollution of lakes by runoff from acid soils
- carbon dioxide discharges and runoff, volcanic or mineral
- chemical waste industrial byproducts
- silt in stormwater runoff from cleared land
Consequences
The toxic chemicals and particles are carried out by the rivers into the ocean. In some areas of the world the influence can be traced hundred miles from the mouth, like in front of the Hudson river. As indicator filter feeding animals are used by the oceanographers, like copepods in the map of New York Bight. The highest toxin loads are not directly in front off New York but 100 km South, because it takes a few days to be incorporated in the tissue of the plankton. The Hudson water flows south along the coast due to the coriolis force. The second map shows areas of oxygen depletion, caused by chemicals using up oxygen and by heavy algae blooms, caused by too much nutrients, when the cells die, sink and decompose. Heavy fish and shellfish kills have been reported. The toxins make their way up the foodchain when small fish eat the copepods, then large fish, each step concentrating up ca. 10 times.
Water Contamination from Texas Instrument
Texas Instruments has a semiconductor facility.chip/chemical factory in Dallas, Texas which uses over 200 gases and chemical compounds. Its leaking USTs, Underground Storage Tanks, since the 1970's have contaminated the air, soil & groundwater and streams nearby with at least 32 VOCs, including, 1,1,1,2- Tetrachloroethane 1,1,1-Trichloroethane 1,1,2-Trichloroethane 1,1-Dichloroethane 1,1-Dichloroethene 1,1-Dichloropropene 1,2,4-Trichlorobenzene 1,2,4-Trimethylbenzene 1,2-Dibromo-3-chloropropane 1,2-Dichlorobenzene 1,2-Dichloroethane 1,3,5-Trimethylbenzene 1,3-Dichlorobenzene l,4-Dichlorobenzene 2-Butanone 2-2-Dichloropropane 2-Chlorotoluene Benzene Butyl Acetate Chlorobenzene Chloroethane Chloroform (Trichloromethane) Chloromethane cis-l,2-Dichloroethene Dibromochloromethane Dichlorodifluoromethane Ethyl Benzene Heptane Hexachlorobutadiene Isopropanol Isopropylbenzene Methylene Chloride n-Butylbenzene n-Propylbenzene Naphthalene p-Isopropyltoluene sec-Butylbenzene tert-Butylbenzene Tetrachloroethene Toluene Total Xylenes trans-l ,2- Dichloroethene Trichloroethene Trichlorofluoromethane Vinyl Chloride (Chloroethylene)
32 chemical compounds discovered so far
The groundwater near the Texas Instruments semiconductor wafer fab (chip factory) in Dallas, Texas flows through the Austin Chalk Formation, about 15 to 25 feet under the surface. TI is basically a chemical factory for making silicon chips and uses hundreds of different chemicals. Leaking USTs (Underground Storage Tanks) filled with solvents and other chemicals have infiltrated and contaminated the groundwater. Monitoring Wells have been used to identify the toxic chemicals such as xylenes, phenols, etc. TI has announced that its latest factory will use 1.5 million gallons of water per day. And there are already several factories on the TI Dallas site.
The groundwater 'seepage' entered the nearby creeks, Cottonwood Creek and Floyd Branch Creek and contaminated them. The residents reported fishing in the creeks until they observed that the fish were deformed and the frogs had tumors growing on them. Then one day all the fish died and now the creeks are lifeless. No fish or insects. The un-reinforced banks of the creeks are collapsing due to the lack of vegetation and root structure.
Beginning with the recent Dallas High-Five construction project near the TI factories, the residents have reported that trees have died and residents who worked in their gardens have developed cancer and died.
See also
External Links
- U.S. Environmental Protection Agency Homepage
- Kentucky Division of Water Homepage
- Natural Resources Defense Council (NRDC): overviews, news and reports on water pollution
- Troubled Waters: Episode and web site from National Geographic/PBS's "Strange Days on Planet Earth"
