WATER POLLUTION

Water pollution

What is it?

The contamination of water in lakes, rivers, oceans, aquifers and groundwater.

Water pollution occurs when pollutants

are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.

Categories of water pollution

Point source refers to contaminants that enter the water from a single, easy-to-identify source like a pipe or a storm drain.

Categories of water pollution Non-point source pollution is pollution

that comes from a big area and not from a single, easy-to-identify source like an agricultural field or a shopping centre parking lot.

Point and Nonpoint Sources

NONPOINT SOURCES

Urban streets

Suburban development

Wastewater treatment plant

Rural homes

Cropland

Factory

Animal feedlot

POINT SOURCES

Type of water pollution

Bacteria,Viruses,Protozoa, Parasitic worms

Oxygen demanding substances Inorganic plant nutrients Organic chemicals Sediment or suspended matter Thermal pollution Genetic pollution

1. Bacteria & Co.

Often comes from fecal (poop) material – untreated or poorly treated sewage, farmers’ fields (animal poop) or septic tanks

Major cause of acute contamination of human drinking water – can immediately make people sick

Major issues: E. coli, giardia, cryptosporidium, Norovirus

1. Bacteria & Co.

Health Impacts? – diarrhea, vomiting, etc.

Preventing contamination? Treated by water treatment plants –

various chemicals Filtering or boiling well water and water

that you are not sure about

Access to clean water

Not everyone in the world has access to clean water – we are lucky here in Canada!

Solutions?

Type of water pollution

Bacteria,Viruses,Protozoa, Parasitic worms

Oxygen demanding substances Inorganic plant nutrients Organic chemicals Sediment or suspended matter Thermal pollution Genetic pollution

Oxygen demanding substances Usually organic compounds that are

broken down by bacteria that need oxygen

Like what? Green waste (leaves, grass cuttings,

etc.), food waste, garbage

Oxygen demanding substancesSo what?

When there are many organic compounds decomposing at the same time (and consuming oxygen), they can reduce the amount of oxygen available to suffocate organisms that need oxygen to live.

Could kill plants and fish in the water!

What can happen? Fish kills….

Type of water pollution

Bacteria,Viruses,Protozoa, Parasitic worms

Oxygen demanding substances Inorganic plant nutrients Organic chemicals Sediment or suspended matter Thermal pollution Genetic pollution

Inorganic plant nutrients

What is inorganic? A chemical compound that does not

have any carbon (C) in it.

Examples: nitrate (NO3-), phosphate (PO43-), sulfate

Inorganic plant nutrients

Where do they come from ?

Agricultural fields (fertilizer or manure), feedlots, septic tanks….

Inorganic plant nutrients

Where do nitrates, phosphates and sulfates end up?

In surface water (water we can see) In ground water

Inorganic plant nutrients

What is the problem?

1.Eutrophication of water bodies – too many nutrients

2.Harmful health effects – blue baby syndrome and cancer

1. Eutrophication

Eutrophication – also known as lots of nutrients, more than necessary, released into a water body

Eutrophication comes from too much nitrogen, phosphorus and sulfate from fertilizers used in agriculture, septic tanks and industry.

Problems with eutrophication Too many nutrients – more algae will

grow

Algae use up all the oxygen in the water

Low oxygen in the water means there is none left for other organisms in the water

That means that fish and insects could die

Too many algae on the surface of the water could block the sunlight – no light to water plants, they can die

Some algae can produce toxins – red tide

Toxins can move up the food chain

Eutrophication

Eutrophication cont’d….

2. Blue-baby syndrome

- infants under 4 months of age who drink well water with nitrates

- Nitrates turn into other chemicals in the body and make it difficult for the body to take up oxygen

- Blue-baby syndrome can lead to fatigue, coma, convulsions, asphyxia and death

Rainbow smelt1.04 ppm

Zooplankton0.123 ppm

Phytoplankton0.0025 ppm

Water0.000002 ppm

Herring gull124 ppm

Lake trout4.83 ppm

Herring gull eggs124 ppm

Biological Magnification

Biological Magnification

Pollution of Lakes

Eutrophication Eutrophication Discharge of untreated

municipal sewage(nitrates and phosphates)

Nitrogen compoundsproduced by cars

and factories

Discharge of treatedmunicipal sewage

(primary and secondarytreatment:

nitrates and phosphates)

Discharge of detergents

( phosphates)

Natural runoff(nitrates andphosphates

Manure runoffFrom feedlots(nitrates andPhosphates,

ammonia)

Dissolving of nitrogen oxides

(from internal combustionengines and furnaces)

Runoff and erosion(from from cultivation,mining, construction,

and poor land use)

Runoff from streets,lawns, and construction

lots (nitrates andphosphates)

Lake ecosystemnutrient overload

and breakdown of chemical cycling

Fig .22.7, p. 499

Fig. 20-12

Aquifer

Water well

Migrating vapor phase

Contaminant plume moveswith the groundwater

Free gasolinedissolves ingroundwater(dissolved phase)

Groundwaterflow

Watertable

Gasolineleakage plume(liquid phase)

Leakingtank

Bedrock

Groundwater Pollution: Causes

Coal strip mine runoff

Pumping well

Waste lagoon

Accidental spills

Groundwater flow

Confined aquifer

Discharge

Leakage from faulty casing

Hazardous waste injection well

Pesticides

Gasoline station

Buried gasoline and solvent tank

Sewer

Cesspool septic tank

De-icing road salt

Unconfined freshwater aquifer

Confined freshwater aquifer

Water pumping well Landfill

Fig. 20-11

Fig. 21-10, p. 505

Healthy zoneClear, oxygen-richwaters promote growthof plankton and sea grasses,and support fish.

Oxygen-depleted zoneSedimentation and algaeovergrowth reduce sunlight,kill beneficial sea grasses, useup oxygen, and degrade habitat.

Red tidesExcess nitrogen causesexplosive growth of toxicmicroscopic algae,poisoning fish andmarine mammals.

FarmsRunoff of pesticides, manure, and fertilizers adds toxins and excess nitrogen and phosphorus.

Toxic sedimentsChemicals and toxic metals contaminate shellfish beds, kill spawning fish, andaccumulate in the tissues of bottom feeders.

Construction sitesSediments are washed intowaterways, choking fish and plants, clouding waters, and blocking sunlight.

Urban sprawlBacteria and viruses fromsewers and septic tanks contaminate shellfish beds

Oxygen-depletedzone

Closedbeach

CitiesToxic metals and oil from streets and parking lots pollute waters;

IndustryNitrogen oxidesfrom autos andsmokestacks,toxic chemicals,and heavy metals in effluents flow into bays and estuaries.

Closedshellfish beds

Global Outlook: Stream Pollution in Developing Countries

Water in many of central China's rivers are greenish black from uncontrolled pollution by thousands of factories.

Figure 20-7Figure 20-7

Case Study: India’s Ganges River: Religion, Poverty, and Health

Religious beliefs, cultural traditions, poverty, and a large population interact to cause severe pollution of the Ganges River in India. Very little of the sewage is treated. Hindu believe in cremating the dead to free the

soul and throwing the ashes in the holy Ganges. Some are too poor to afford the wood to fully

cremate. Decomposing bodies promote disease and depletes

DO.

Case Study: India’s Ganges River: Religion, Poverty, and Health

Daily, more than 1 million Hindus in India bathe, drink from, or carry out religious ceremonies in the highly polluted Ganges River.

Is Bottled Water the Answer? Some bottled water is not as pure as tap

water and costs much more. 1.4 million metric tons of plastic bottles

are thrown away. Fossil fuels are used to make plastic

bottles. The oil used to produce plastic bottles in the

U.S. each year would fuel 100,000 cars.