ENVIRSC 1C03 Lecture Notes - Lecture 20: Biochemical Oxygen Demand, Polycyclic Aromatic Hydrocarbon, Triazine
3 Sep 2018
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Document Summary
Chemical pollutants including pesticides like ddt, parathion and triazine. Heavy metals like pb, zn, cd, as, u. Heat which impacts endogenous populations of fish. If water discharged into the receiving environment is too got it limits o2 availability. If water is too cold, the populations may not be adapted to such temps. These pollutants may be introduced from point or nonpoint sources. A specific spot where large quantities of pollutants are discharged. Often consists of small point sources distributed over a wide area. Groundwater can be polluted by defective on-site septic systems, leaky tanks or pipelines containing petroleum products, and leaks/spills of industrial chemicals at factories. For example, contamination of groundwater w dry cleaning agents & solvents such as toluene & trichloroethylene is a major environmental problem. Pollution can also occur from seepage from municipal landfills, fertilizers dispersed on agricultural land, pesticides sprayed on agricultural lands and forests and from contaminants in wet & dry atmospheric fallout.
