EESA11H3 Lecture Notes - Lecture 8: Cell Growth, Biochemical Oxygen Demand, Heap Leaching
17 Apr 2015
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Lecture 8 eesa11: march 19. The combustion of fossil fuels and waste (such as from hospitals), producing large amounts of mercury in the air. Phosphorus and polychlorinated biphenyls (pcbs) are also transported to waterways via air deposition. Metals: many metals such as mercury, lead, cadmium, and nickel are highly toxic, mercury may be released from incinerators and coal-burning power plants, mine drainage and leaching. Early studies commonly found that fish and the wildlife from various ecosystems can attain levels of mercury of concern to human health. Fish, mainly from nutrient-poor lakes and often in very remote areas usually have high levels of mercury. These emissions of mercury cannot be linked to single point sources of pollution, but are due to widespread air-pollution. Nonmetallic salts: the biggest source is road salt used during the winter, when the snow melts, the salt runs off into nearby rivers or lakes.
