Water Pollution and Quality Measurement

Water Pollution

• Water is the only molecule on Earth that is present in all states of matter.
• The Hydrologic Cycle is the movement of water between reservoirs on either a local or global scale.
• The Hydrologic Cycle includes: Evaporation, Condensation, Precipitation, Infiltration, Groundwater flow, Transpiration, and Overland flow.
• 97% of Earth's water is saltwater in the oceans, and 3% is freshwater.
• The majority of freshwater is stored in ice caps and glaciers.
• 1.2 billion people lack access to clean drinking water.

Water Quality Measurement

• Physical parameters include: Temperature, Suspended solids, and Odor.
• Chemical parameters include: pH, Nutrients, Metals, Pesticides, and Herbicides.
• Biological parameters include: Fish, Bacteria, and Algae.

Dissolved Oxygen

• Dissolved oxygen is a critical water quality parameter that affects the health of aquatic ecosystems and fish.
• Low dissolved oxygen levels can lead to fish mortality and odors.
• Dissolved oxygen levels play a role in fish reproduction.

Biochemical Oxygen Demand

• Biochemical oxygen demand (BOD) is a measure of the amount of oxygen required to biochemically oxidize organic matter present in water.
• BOD levels are related to the amount of biodegradable organic matter present in water.
• High BOD levels indicate the presence of organic waste in water.

Salinity

• Salinity measures the content of salts in soil or water.
• High salinity can lead to environmental damage, agricultural problems, and infrastructure issues.
• High salinity levels can affect machinery, and lead to poor health in vegetation.

Water Pollutants

• Infectious Agents (Pathogens): Bacteria, parasites, and human waste.
• Oxygen Demanding Wastes: Plant debris and sewage.
• Plant Nutrients: Nitrate, sewage and animal wastes.
• Organic Chemicals: Oil, gasoline, industrial and agricultural sources.
• Inorganic Chemicals: Acids, bases, salts, and industrial sources.
• Sediments: Soil, land erosion from farms and urban streets.
• Heavy Metals: Lead, unlined landfills.
• Thermal: Excessive heat, electric power plants.

Major Sources of Water Pollution

• Agriculture: Fertilizers, pesticides, and livestock waste.
• Industries: Manufacturing, chemicals, and mining.
• Mining: Runoff from mining operations.

Point Sources of Water Pollution

• Discharge pollutants at specific locations.
• Easier to identify, monitor, and regulate.

Nonpoint Sources of Water Pollution

• Broad diffuse areas where pollutants are washed into surface waters by rainfall or snowmelt.
• Difficult to identify and regulate.

Pollution of Freshwater Streams

• Streams and rivers cleanse themselves of biodegradable pollutants if not overloaded.
• Cleaning processes include dilution and bacterial biodegradation.
• Overloading can lead to a depletion of dissolved oxygen and the accumulation of pollutants.

Oxygen Sag Curve

• A graphical representation of the depletion and recovery of dissolved oxygen in a stream after a point source of pollution enters the stream.

Steps Towards Reduction of Stream Pollution

• Developed countries have significantly reduced point source pollution.
• Developing countries are struggling with the discharge of untreated sewage and industrial waste.
• Poverty and religious beliefs can contribute to the lack of water treatment facilities and enforcement of water pollution laws.

Pollution of Freshwater Lakes and Reservoirs

• Lakes and reservoirs are more vulnerable to pollution than streams.
• Lakes have a slower water turnover rate than streams, which makes them more susceptible to pollution.
• It can take up to 100 years for the water in a lake to flush and change.

Cultural Eutrophication

• Eutrophication is the natural enrichment of shallow lakes with nutrients.
• Cultural eutrophication is caused by excessive nitrates and phosphates from human sources.
• Cultural eutrophication can lead to algal blooms, oxygen depletion, and fish kills.

Prevention of Cultural Eutrophication

• Waste treatment to remove nitrates and phosphates.
• Soil conservation practices to reduce runoff.
• Banning or limiting the use of phosphates in detergents.

Methods to Clean Up Lakes

• Removing excess weeds.
• Using herbicides to control algae.
• Pumping air into the lake to increase oxygen levels.
• Most lakes will recover if the excessive input of nutrients is stopped.

Great Lakes Water Quality Agreement

• 1972: Great Lakes Water Quality Agreement, new or upgraded treatment plants
• Remaining problems; Increasing nonpoint runoff of pesticides and fertilizers
• Atmospheric deposition, 25% of fish had unsafe mercury content

Great Lakes Restoration Initiative (GLRI)

• 1.3 billion provided, focus on reduce pollution
• Prevention Approach; Call for ban on toxic chlorine compounds

Pollution of Groundwater

• Groundwater can be contaminated with a variety of chemicals.
• Groundwater is a prime source of drinking water and irrigation.
• Common pollutants include fertilizers, gasoline, organic solvents, and fracking chemicals.

Groundwater Pollution Solutions

• Finding substitutes for toxic chemicals.
• Keeping toxic chemicals out of the groundwater.
• Requiring leak detectors on underground storage tanks.
• Banning hazardous waste disposal in landfills.
• Storing harmful liquids in aboveground tanks.

This quiz explores the critical aspects of water pollution and water quality measurement. It covers the hydrologic cycle, the importance of freshwater, and key parameters for assessing water quality. Test your knowledge on dissolved oxygen and its impact on aquatic ecosystems.