Transcript Document
Marine Pollution Pollution in coastal waters Coastal waters are highly affected by pollution because they are: Heavily used Close to sources of pollution Shallow-water bodies Not as well circulated as the open ocean Marine pollution: A definition The introduction by man of substances or energy into the marine environment, which results in harm to marine life, hazards to human health, hindrance to marine activities, including fishing and other legitimate uses of the sea, impairment of quality for use of sea water and reduction of amenities. (WHO) Main types of marine pollution Sewage sludge DDT and PCBs Mercury Nuclear Radiation Non-point-source pollution Petroleum (oil) Marine pollution: Sewage sludge Sewage sludge is the semisolid material that remains after sewage treatment Much sewage sludge was dumped offshore until laws restricted sewage dumping Marine pollution: DDT DDT was a widely used pesticide that became concentrated in marine fish DDT caused brown pelicans and ospreys to produce thin egg shells Worldwide, DDT has been banned from agricultural use but is still used in limited quantities for public health purposes Marine pollution: PCBs PCBs are industrial chemicals used as liquid coolants and insulation in industrial equipment such as power transformers PCBs enter the marine environment through leaks and from discarded equipment PCBs can accumulate in animal tissues and affect reproduction Mercury and Minamata disease Mercury has many industrial uses but is extremely toxic A chemical plant released large quantities of mercury into Minamata Bay, Japan Residents who ate highly contaminated fish suffered neurological disease and birth disorders (Minamata disease) Nuclear Radiation Caused by leaking of containment structures The severity of this contamination depends on the life of the radioactive isotopes that would be released if a meltdown were to occur. Some like iodine 131, would only affect humans if plants and vegetables were consumed immediately after contamination because they quickly degrade. Others, like caesium, are more dangerous because they remain radioactive for about 28 years. Fukushima Daiichi nuclear disaster Fukushima Daiichi nuclear power plant went into a meltdown after an earthquake and 49 foot tsunami destroyed the plant, cooling pumps, and generators on March 11, 2011 Core reactor temperatures reached over 5000◦F. The saga continues as workers try to contain the continually leaking reactors. Radiation’s Effects Fukushima Non-point- source pollution Non-point-source pollution comes from material washed down storm drains as “poison runoff” Includes fertilizers, pesticides, road oil, and trash Law regulating ocean dumping The only substance that is illegal to dump anywhere in the ocean is plastic Plastic in the marine environment Plastic: Does not biodegrade Floats Has high strength Is ingested by and entangles marine animals Marine pollution: Petroleum Oil spills can be caused by: Tanker accidents Intentional dumping Drilling/pumping operations Marine pollution: Petroleum Petroleum is biodegradable Many pollution experts consider oil to be among the least damaging ocean pollutants Data from the 1989 Exxon Valdez oil spill shows the recovery of key organisms Exxon Valdez 1989 Prince William Sound, Alaska Hit a reef Ship leaked 11 million gallons of oil from a tank Some oil still left after 22 years BP Deepwater Horizon Rig April 20, 2010 Drilling rig exploded Gulf of Mexico (48 mi. from Mississippi River) Over 6 million gallons so far Huge reservoir of oil that is leaking (not as limited as ship leak) Has entered Loop Current Examples of damage… 11 workers are presumed dead 187 turtles stranded 18 dead dolphins Hundreds of bird nests Pelican covered in oil, Associated Press Dangers to Wildlife Damage to sea grasses that hold wetlands together Over 70% of US water birds use Lousiana’s wetlands for rest or nesting Danger for fisheries (oysters & trout are spawning this time of year) Harm to Florida coral reefs Ways to Clean Up Oil Spills Booms Skimmers Sorbents Dispersants Burning Bacterial breakdown Kevin Costner’s centrifuge Various processes break up and degrade oil in the marine environment Marine pollution: Petroleum When oil washes up at a beach, it can negatively affect the marine environment Oil can coat marine organisms and render their insulating fur or feathers useless Oil on the beach from the Exxon Valdez oil spill, Alaska