Water Pollution
Any change in water quality that has a harmful effect on living organisms
Any change that makes the water unsuitable for the use intended
Chemical
Biological
Physical
Thermal
Safe Drinking Water
95% in developed countries have safe drinking water
74% in developing countries
1.4 billion lack safe water
9,300 die/day: contaminated water or lack of adequate hygiene
Water Quality
Tests and analyses of water samples
Fecal coliform test
Coliforms inhabit intestines of human and other animals
Presence indicates water has been exposed to wastes that may carry pathogens
Fecal Coliforms
Not all coliforms cause disease
Pass water through filter
Place filter on culture medium
Grow out bacteria for 24 hours
Safe for drinking—no colonies in sample size of 100 ml
Fecal Coliforms
Safe for swimming ≤200 colonies/ 100 ml
Raw sewage—several million colonies/100 ml
High readings—determine source
Look at different strains
Identify source—humans, pets, livestock
Dissolved Oxygen
Related to amount of oxygen-demanding wastes
Organic materials that are usually biodegradable by aerobic bacteria if there is enough dissolved oxygen in the water
Biological Oxygen Demand
Amount of dissolved oxygen consumed by aquatic decomposers
Given volume of water at a certain temperature over a specific time period
Chemical Analyses
Presence and concentration of organic and inorganic chemicals that pollute water
Various methods, various machines
Sediment content—measure weight of sediment
Suspended sediment—measure turbidity of sample
Living organisms
Indicator species: cattail, mussels, rockfish
Plants and bottom dwellers or filter feeders
Biosensors: bioengineered bacteria or fungi glow in presence of specific pollutant
Sources
Single source—point source
Release at specific locations
Drain pipes, sewage lines
Easier to identify, monitor, regulate sources
Sources
Nonpoint sources—scattered and diffuse
Not traced to single discharge site
Acid deposition (rain), runoff of agricultural chemicals, urban runoff, lawns, golf courses
Difficult to identify and control source
Activities Producing Pollution
Food production
Sediment from cropland and rangelands
Fertilizers
Pesticides
Bacteria from livestock
Food processing wastes
Excess salts
Activities Producing Pollution
Making things—industrial facilities and mining
Industrial wastewater
Acid deposition
Sediments toxic chemical runoff
Acid drainage
Infectious Agents
Typhoid, cholera, bacterial and amoebic dysentery, polio, hepatitis A, schistosomiasis—contaminated water
Malaria, yellow fever, dengue fever, filariaisis—insects with aquatic larvae
Infectious Waste
Sewage treatment facilities—treat human waste
Water treatment—chlorination and filtration
Keep two streams separate
Rehydration cocktail—clean water, sugar, salt
Oxygen-Demanding Waste
Oxygen content above 6 ppm supports game fish
< 2ppm—worms, bacteria, fungi
Add O2—turbulence and diffusion
Deplete O2—respiration and chemical processes
Oxygen-demanding Waste
BOD
COD
DO—more related to organism survival, measures pollutants, but is also function of temperature and aeration
Fresh Water Streams &OD Waste
Effects on streams depends on volume, flow and temperature
Combination of dilution and biodegradation—natural processes help
Moderate pollution loads
Fresh Water Streams &OD waste
Oxygen sag curve—oxygen depleted as bacteria breaks pollutants down
Hits populations with high O demands
Recover downstream
Factors include—waste volume, stream volume, flow rate, turbulence, temperature, pH
Lakes and OD Wastes
OD wastes more problematic
Layers of lake allow little mixing
Little flow
Little discharge
Agricultural chemicals, oils, lead, mercury, selenium
Biomagnification
Water Quality
Oligotrophic—clear water, low biological activity
Eutrophic—rich in organisms and organic materials
Eutrophication
Natural nutrient enrichment of lakes, nitrates and phosphates
Increase phytoplankton -> increase fish
Cultural eutrophication—increase from human activities
Blooms of plant and bacterial growth
May reduce productivity
Cultural Eutrophication
Decaying organisms depletes O
If continuous, aerobic organisms die
Anerobics take over
Produce methane and hydrogen sulfide
Eutrophication and Marine Systems
Nearshore waters, bays, estuaries
Dead zones—Mississippi River and Gulf of Mexico, NileRiver and MeditteranianSea
Toxic tides—red tides, dinoflagellates, Pfiesteriapiscisida
Inorganic Chemicals
Water-soluble
Acids, toxic metals (lead, arsenic, selenium), salts (sodium chloride) and flourides
Inorganic Chemicals
Make fresh water unusable
Skin cancers, spine and neck damage
Nervous system damage
Harm fish and aquatic life
Lower crop yields
Accelerate metal corrosion
Inorganic Pollutants
Weathering of rocks
Industrial activities
Metals—lead, mercury
Non-metallic salts—selenium, arsenic
Acids and bases—acid deposition
Alkaline soils (with limestone)—help to neutralize
Organic Chemicals
Chemical, pharmaceuticals and plastics
Oil, gasoline, cleaning solvents, detergents
Nervous system damage
Cancers
Harm fish and wildlife
Thermal Pollution
Temperature change (+ or - ) alters water quality and ability to support life
Water temperature changes alter ability to hold O
Warmer temperature, less O
Industrial and power plants use water to cool
Thermal Pollution
Restrictions on how much temperature change is allowed
Animals attracted to warmth and food source
Alter plant life
Sediment
Erosion rates increase as result of human activities
Sediments fill lakes, alter shipping channels
Cover eggs and bottom dwelling animals
Blocked sunlight
Sediment
Rebuild wetlands
Deposit nutrient laden silt
Build land
Groundwater Pollution
So far, “easy”
Groundwater—invisible but valuable
Major source of drinking water
Once contaminated, pollutants hard to remove
Groundwater
Pollution moves from site of introduction
Forms plume
Contaminated water may be used for drinking or agricultural water
Groundwater
Degradable waste not degraded
Slow flow—no dilution or dispersion
Lower dissolved O
Lower numbers of aerobic decomposing bacteria
Lower temperature
Nondegradable waste not degraded
Groundwater Pollution
Identification, monitoring, remediation—expensive
Municipal groundwater supplies contaminated—45% in U. S.
Industrial waste ponds and lagoons leak
Acids, wood preservatives, fuels
Groundwater Pollution
Leaking Underground Storage Tanks
Historically 85% leakage
Silicon Valley
Leaking gasoline storage
Cleanup costs--$10,000 to $250,000 per tank
Groundwater Pollution
Military facilities
Wash facilities
Fuel dumps
Explosive washouts
Etc.
Groundwater Pollution
Leaking landfills
No liner or cracked liner
Deep well injection
Should not have migrated into groundwater
Ocean Pollution
Materials on land end up in ocean
Oils, metals, solvents, sediments
Solid waste—ends up in ocean
After storm—mountains of waste end up in LA and San GabrielRivers, transported to ocean and beaches
Ocean Pollution
Federal law requires clean up before solid waste hits ocean
Temporary dams, barricades
Stay out of water for three days minimum before swimming
Ocean Pollution—Oil
Oil tanker spills—dramatic, ship impaled on rocks
Intensive clean-up efforts and costs
Greater impact overall—land-based activities, waste oil, washing and loading oil tankers & ships
Ocean Pollution—Oil
Effects depend on
Type of oil: crude or refined
Type of system: open ocean, bay, estuary
Amount released
Distance from shore
Time of year
Weather conditions
Average water temperature
Ocean currents
Oil Pollution
VOCs—immediately kill several types of organisms
Tar-like globs float and cover ocean and shore birds
Heavy oil sinks to bottom—smothers bottom-dwelling organisms
Oil Pollution
Rule of thumb for recovery time from exposure to large exposures—
Crude oil—3 years
Refined oil—10-15 years
Water Pollution Control
Source Reduction
Don’t produce
Don’t release
Alter agriculture practice
NonpointSource
Agriculture—erosion, agriculture chemicals, animal waste
Urban runoff—salts, oil rubber metals, fertilizer
Construction sites—sediment, barriers and filters on catch basins
Land disposal—leaking liners