Water Quality APES Ch. 14

Heavy Metals  Lead:  Rarely found naturally in drinking water  Contaminates through lead containing pipes, solder, & brass fittings  Fetuses and infants are most sensitive  Effects: brain-damage, damage nervous system & kidneys

Heavy Metals  Arsenic:  Occurs naturally in rocks; can be dissolved in groundwater  Human activity like mining & industrial uses  Can be removed by filtration or reverse osmosis  Associated with cancers  EPA standard in drinking water is 10 μ g/L  140 million in India drink arsenic contaminated drinking water

Heavy Metals  Mercury:  Occurs naturally but increasing in drinking water due to human activity  Human activity:  Coal burning  Incineration of garbage  Hazardous waste  Medical & dental supplies  Manufacture of cement (release from limestone in heating process)  Petroleum exploration (contaminated wastewater)

Heavy Metals  Mercury Cont.:  Inorganic Hg is not harmful but when released into environment changed in methylmercury by bacteria  Effects:  Damage central nerve system (touch, taste, sight)  Fetus and infants particularly susceptible  Human exposure to methylmercury occurs mostly from fish & shellfish  Bioaccumulation up the food chain  EPA: reduction of mercury emissions in cement manufacturing & coal-burning power plants

Acid Deposition  Acid Deposition: Release of sulfur dioxide & nitrogen dioxide in atmosphere by industry is converted into sulfuric acid/nitric acid and deposited 100’s km away in form of rain or snow (a.k.a acid rain).  Reduced pH in water bodies  Lethal to aquatic organisms  Coal scrubbers remove acidic gases  Underground acidic water comes from mining (reaction with pyrite)  Reaction with acidic water can cause other harmful metals to become soluble

Synthetics: Pesticides  Concerns:  Kill indiscriminately; lethal to unrelated species  Ex: Endosulfan pesticide kills amphibians  Side effects of pesticides can effect other species in unintended ways.  Ex: DDT & Bald Eagle  Inert ingredients make pesticide more effective  Ex: Roundup ingredient (used to penetrate waxy leaves) is highly toxic to amphibians

Synthetics: Pharmaceuticals & Hormones  Common in streams:  50% of tested streams contain antibiotics & reproductive hormones  80% contain non-prescription drugs  90% contain steroids  Low risk due to low concentrations but hormones can effect tissues & are poorly understood  Extent of hormone effects not understood

Synthetics: Industrial Compounds  Chemicals used in manufacturing  Used to be dumped directly into bodies of water  Ex: Cuyahoga River – all animal life killed, caught on fire several times; 1969 fire lead to movement to clean- up waterways.  PCB (polychlorinate biphenyls)  Manufacture of plastics & electrical transformers  Lethal carcinogen that is still in the environment (US stopped in 1979)  Dredging sediments for PCB’s in 2009

Synthetics: Industrial Compounds  PBDE’s (polybrominated diphenyl ethers)  Mostly used in flame retardants in construction, electronics, & clothing  Causing concern: detected in fish, aquatic birds, & human breast milk  Can lead to brain damage in children  EU, WA & CA have banned the manufacture

Oil Pollution  Petroleum products are highly toxic to marine organisms including algae (base of food chain)  Persistent  Extremely difficult to remove  Sources:  Undersea drilling platforms (5,000 in US) -  Leak estimate – 146,000 kg (322,000 lbs) in NA; global – 0.3 to 1.4 million kg  Ex: 2010 BP Oil Spill (206 million gal) contaminated beaches, estuaries (habitat for fish & shellfish); one of largest environmental disasters in US history

Oil Pollution  Oil Tanker spills –  Ex: Exxon Valdez in 1989 leaked 11 million gallons in Gulf of Alaska  Killed 250,000 seabirds, 2,800 sea otters, 300 harbor seals, & 22 orca  20 years later -  Clean-up is still continuing today  Harmed populations rebounded including bald eagles & salmon; not rebounded, killer whales & sea otters  14,500 estimated gallons remain in ecosystems  Now ships required to have double-hulled design  Large fraction of oil in ocean occurs naturally

Oil Pollution Remediation  Oil can either float or remain far below in plumes  Remediation methods:  Birds & mammals – cleaned by hand  Floating oil –  Contain it with a boom (plastic barriers) & then suck it off the surface  Apply chemicals that break-up the oil; can be toxic  Genetically engineered bacteria that consumes oil  Underwater plumes –  Currently (BP spill) there is a plume that is 15 x 5 3,000 ft below  No agreed upon method