Ch 11 Water Pollution

1. Ch 11 Water Pollution

2. 11.1 Types of Water Pollution • Pollution - Any contamination of water that lessens its value to humans or other species, aquatic or nonaquatic • Point Source Water Pollution • Has a well defined location where the pollutants enter surface or ground water • Ex: sewage • Nonpoint Source Water Pollution • Pollutants come from a large area, no specific location • EX: pesticides or fertilizers, construction sites, streets

4. 11.2 Major Pollutants • Classified according to their chemical type • Sediment, inorganic nutrients, thermal, disease-producing microorganisms, toxic organic chemicals, heavy metals, oxygen demanding organic waste • Pollution control devices – remove pollutants from the effluents of factories and sewage treatment plants, used for point source • Output control – deal with pollutants after they have been produced

5. Pollution prevention – reduce or eliminate pollutants in a cost effective way for companies and individuals • Nontoxic substitutes for chemicals • Sediment Pollution • Sediment includes sand, silt, and clay that have eroded from soils and washed from land • Mississippi River carries 210 million metric tons of sediment to Gulf of Mexico each year • Can damage turbines, clog irrigation canals, fill channels for navigation • Block sunlight

6. Control of Sedimentation • Input Control – preventive measure to stop or control soil erosion • Output Control – direct muddy water to marshes or wetlands • Inorganic Nutrient Pollution • Nitrates and phosphates • Sources – agriculture, domestic sewage, livestock waste • Effects on Aquatic Ecosystems –phosphorus are usually limiting nutrients, a large input from runoff can cause an algal bloom

7. Eutrophication • The nutrient enrichment of an aquatic ecosystem • Natural eutrophication – occurs over long periods of time, maybe thousands of years • Cultural eutrophication – human activities speed up the process • Classifying Lakes based on Productivity • Oligotrophic lake – clear water lakes, surrounded by spruce and pine forests, very little algae, low levels of dissolved nutrients, low biomass per unit • Mesotrophic lake – moderate levels of nutrients, intermediate fertility, clarity, dissolved oxygen, and total biomass

8. Eutrophic lake – high levels of nutrients, turbid water, abundant plankton • Have frequent algal blooms • May destroy aesthetic of lake or pond • Decrease quality of water for drinking • Piles of algae on shore and release H2S • Proliferation of blue-green algae, some can be toxic • HW: pg 303 #1-4, 6, 8

9. Thermal Pollution • An increase in the temperature of water that adversely affects organisms living in it • Sources of thermal pollution – natural causes (summer heating) and human actions • Electric utilities, steel manufacturing, chemical plants • Thermal plume – a heated body of water • Can extend for 1km

10. Biological Effects of Thermal Pollution • Reduction in Dissolved Oxygen • Interference with Reproduction • Increased vulnerability to disease • Direct mortality • Invasion of destructive organisms • Undesirable changes in algal populations • Destruction of organisms in cooling water • Control of Thermal Pollution • Power plants can reduce or eliminate by installing cooling towers • Beneficial Effects of Heated Water • Can help vegetation near the warmed water, increased growth rate of lobsters, attracted desirable fish

11. Disease Producing Organisms • Responsible for more human illness world wide than any other environmental factor • Cholera, typhoid fever, dysentery, polio, hepatitis • In US Pfiesteria is a problem for wildlife • Causes open sores and massive fish kills in coastal waters • Feeds on algae and in large numbers releases toxins into the water that stuns the fish and can break down the skin, causing the sores

12. Protecting from Pathogens • Starts with good sewage treatment • Purification of drinking water • Coliform bacteria testing is used to test for the safety of drinking water • Chlorination is used to kill bacteria and viruses • Toxic Organic Compounds • Many of the man made organic compounds resist decomposition by bacteria • EX: DDT and PCBs • Plasticizers – chemicals added to plastic to make it less brittle • Found in water bottles and even linings of metal cans • May have heard of BPA????

13. Groundwater Contamination • Most contamination comes from municipal and industrial landfills • Adverse Effects on Health • Kidney damage and birth defects • Ground water contamination mostly comes from improper disposal of hazardous waste • Heavy Metal Pollution • Heavy metals are toxic elements like lead and mercury • Can come from underground mines, gaseous emissions of coal power plants, garbage incinerators, industrial facilities

14. Can be released into waterways from metal-processing plants, dye-,making firms, and paper mills • Heavy metals interfere with the function of important enzymes • Lead Poisoning – decreased learning ability, gastric upset, convulsions, coma, death; mental retardation and stunted growth in children • Mercury – can come from industrial discharge and rain and snow (coal fired power plants and garbage incinerators that burn batteries) • Biological magnification

15. HW: pg 303 11,12,14,15