Water QualityWater QualityAPES Ch. 14APES 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 μg/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 mi @ 3,000 ft below

No agreed upon method