Water Pollution

Part I

Sources - General Point Source: when a harmful substance

is released directly into a body of waterUsually monitored and regulated in

developing countriesEx: industrial discharge into a river

Non-point source: deliver pollutants through transport or environmental changeIndirect and more difficult to monitor and

controlEx: fertilized from a farmers feild

Sources - Air pollution:

mercury, sulfur dioxide, nitric oxides, and ammonia fall out of the air and into bodies of water Cause: Acidification, eutrophication and

contamination of fish

Sources – Methyl Mercury

Inorganic mercury enters water systems and is converted to methyl mercury by bacteria

Enters food chain and bioaccumulates Humans exposed by eating

contaminated fish Methyl mercury is more toxic than

inorganic mercury Organisms take a long time to process

out methyl mercury

Sources – Other chemicals Variety of chemicals Bioaccumulate and poison fish, marine

mammals, birds, and humans Affect the development and reproduction of

various marine animals Examples:

Metals Solvents Oils Detergents Pesticides Prescription drugs

●Hormones

●Antibiotics

●Personal care products

●Household products

Sources - Microbial Pathogenic (disease-causing)

microorganisms (bacteria, viruses, protozoa)Ex: cholera, typhoid, polio, meningitis,

hepatitis, “Montezuma's revenge” Infects drinking sources when raw

sewage is dumped into rivers, lakes, and bays 90% of sewage in developing world is raw

Leaking septic tanks and other sources contaminate groundwater and streams

Sources - Mining Methods of contamination:

Exposes heavy metals and sulfur compounds that can leach out of rock and into water sources

Rainwater washes chemicals out of mining waste and into water sources

Pools of mining waste leak and contaminate ground water

Direct dumping of mining waste into rivers Examples:

2003 – US reclassified mining waste from mountain top removal so it could be dumped in valleys

Iron Mountain mine in CA – closed in 1963, still drains sulfuric acid and heavy metals into the Sacramento river

Sources - Noise

Commercial shipping, military sonar, recreational boating create noise that interferes with marine organisms who use sound to communicate, navigate, and hunt

Sources - Nutrients

Phosphorus and Nitrogen from fertilizers cause algal blooms

Damages rivers, lakes, oceans, estuaries, and deltas

Sources – Oil Spills From ship and well leaks and spills Effects:

Coats sea birds making them more vulnerable to temperature fluctuations and poisons them when they clean themselves

Poisons food sources and leads to bioaccumulation

Limits photosynthesis Clean up:

Use microorganisms to “eat oil” Use chemical agents to try to control oil for

clean up Controlled burning, skimming, booming,

vacuuming oil from surface and shorelines

Sources – Oxygen-depleting Substances

Biodegradable wastes serve as food for microorganisms which take oxygen out of the water

Results in:Anoxic water and fish killsIncreased activity from anaerobic

bacteria which produce ammonia, amines, sulfides, methane

Source - Plastic From litter that enters watersheds Problems:

Plastic photodegrades into smaller pieces Leach chemical toxins into environment Consumed by marine animals and clogs their

digestive tracks Gets caught on animals Spread invasive species Absorb toxins and then leach them into upper

water column Makes it more difficult for animals to see and

capture real food Affect 250+ species world wide

Sources – Suspended Matter

Suspended waste settles out and contaminates mud at the bottom of rivers affecting organisms throughout the food web

Can include, silt, plastics, other forms of trash

Sources - Thermal Produced by industry Reduces the ability of water to hold oxygen Causes death of animals with low tolerance to

heat and low oxygen conditions Can change species composition of the area

Case Study - Minamata disease Between 1932 and 1968, 27 tons of

mercury- containing chemicals were dumped into Minamata Bay, Japan

Mercury accumulate in fish and shellfish caught in the bay

Disease symptoms (mercury poisoning): blurred vision, hearing loss, loss of muscular coordination, reproductive disorders

Case Studies – Oil Spills Exxon Valdez (1989):

Oil tanker ran aground Dumped 11 – 30 million gallons in Prince

William Sound, Alaska Destroyed the habitat from plankton on up

Deepwater Horizon (2010): Following an explosion on the Deepwater

Horizon, well spilled oil into Gulf of Mexico for months

Most significant environmental disaster in the US

Oil followed currents, contaminated the Gulf Coast

Damage to fishing, tourism, and other industries Environmental damage to many habitats