Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Key Ideas l Pollution can come from both human and natural sources. l There are many different types of pollutants, each with different characteristics. l Pollutants can be biologically magnified in food chains. l Some changes in global weather and climate are due to pollution. 1 Marine Pollution How are marine pollutants classified? • Natural pollutants • Human generated pollutants 2 1 Characteristics of a Pollutant Quantity - the amount of a particular pollutant present Toxicity - the amount of a pollutant required to cause damage Persistence - the length of time a pollutant lasts in an environment 3 Major Types of Pollutants l l l l l Sewage Trace metals Oil Synthetic organic compounds Gaseous emissions 4 2 Sources of Oil Pollution 5 Oil Pollution What is the difference between a crude oil spill and a refined oil spill? Crude oil spills are usually larger in volume, and occur more frequently than spills of refined oil. Refined oil spills can be more disruptive for longer periods of time. Components added to oil in the refining process make it more deadly. 6 3 Fate of an Oil Spill 7 8 4 Oil Spills l l l l l l l 5 - 10 million tons per year Loss of volatiles - 25% in days Emulsification - mixing of oil and water (“chocolate mousse”); eventually settles Photo-oxidation - harmless products Microbial oxidation - harmless products After 3 months, only black tarry lumps (“tar balls”) - 15% Nearshore - limited space and time for these processes 9 Biological and Physical Effects l l l l l Range from bad taste to carcinogenic to toxic Low-boiling aromatics - most toxic and carcinogenic; effect decreases with time due to volatility Low-boiling saturated HCs - anesthesia to toxic Stored in fatty tissues Concentrated up the food chain 10 5 11 12 6 Annual Global Oil Spillage 13 Heavy Metals Small quantities of heavy metals can cause damage to organisms. Some examples of heavy metals that can be toxic are: • Lead • Mercury • Copper • Tributyl tin 14 7 Sources of Heavy Metal Pollution • Coal combustion • Electric utilities • Steel and iron manufacturing • Fuel oils • Fuel additives • Incineration of urban refuse 15 16 8 Synthetic Organic Chemicals 17 Synthetic Organic Chemicals Biological amplification of DDT in a food chain. 18 9 Eutrophication Excess nutrients caused by pollution can speed the growth of marine autotrophs. This process is called eutrophication. Eutrophication stimulates the growth of some species and upsets the natural balance of an ocean area. 19 Eutrophication Dead zones caused by eutrophication. Nutrient runoff from farmlands causes excess growth of autotrophs, which in turn depletes the oxygen in an area. 20 10 Dead Zone, Gulf of Mexico 21 Size of Gulf of Mexico Dead Zone 22 11 Solid Wastes and Waste Heat Solid wastes, especially plastics, can cause damage to marine ecosystems. Electrical generating plants give off waste heat, which can damage ecosystems and harm organisms. 23 Introduced Species Ballast water of ships allows species to travel to environments where they have no natural predators. Introduced species often upset the ecological balance of an area. 24 12 Habitat Destruction What marine habitats are most likely to be damaged by pollution? • Bays and estuaries • Coral reefs 25 Global Changes What global changes have been caused by pollution? • Ozone layer depletion, caused by CFCs • Global warming due to increased greenhouse gases How the greenhouse effect works. 26 13 Summary Establishing marine sanctuaries is one action that preserves and protects marine environments. The solution to environmental problems, 27 if one exists, lies in education and action. 14