FNR 10300 Lecture 27: Surface water pollution lecture 27
31 Oct 2016
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Document Summary
Discharge pollution from specific locations: drain pipes, ditches, sewer outfalls. No specific location where they discharge into a particular body of water. Major progress in cleaning up polluted rivers and lakes. Tough to point a finger and assign responsibility. Mercury - most widespread toxic metal in contaminant in north america. Sodium chloride: road salt in winter, runoff can increase salinity, harm ecosystems. Used in making pesticides, plastics, pharmaceuticals, pigments, etc. Pesticide and herbicide runoff: farm fields, forests, roads, golf courses & lawns. E. coli, dysentery, cholera, typhoid, polio, for example: assumed to be present if coliform (lives in colon) bacteria are present. Increases oxygen consumption: decomposition in water through action of detritivores. Oxygen removed by respiration and chemical processes. Biochemical oxygen demand (bod: dissolved oxygen consumed by microorganisms. Oligotrophic (oligo=little, trophic=nutrition: clear water, low biological productivity. Eutrophic (eu=good; well-nourished: rich in organic materials and organisms. Natural sedimentation and nutrient influx from streams: lakes can fill in, become marshes.
