Water Pollution

Distribution of Water Reservoirs Oceans 97% Atmosphere 0.01% Rivers, Lakes, and Inland Seas 0.141% Soil Moisture % Ground Water 0.4 – 1.7% Ice Caps and Glaciers 1.725%

World Water Supply % salt water in the oceans % ice caps and glaciers % groundwater % surface water % soil moisture % atmospheric moisture

Water Cycle Atm. - Ocean - Land Evap. - PPT - Runoff

Water Pollution Two major classifications Point SourceNon-point Source

Point Sources Single large source Can localize it to one spot –Industrial Plants - Sewage pipes

Point Source - Example LUST - Leaky Underground Storage Tanks 22% of the 1.2 million UST are LUST

Non-point Sources Diffuse source or many smaller point sources Automobiles Fertilizer on fields

Water Pollution: Many Forms Disease: In developing nations, 80% of diseases are water-related. Synthetic Organic Compounds Inorganic Compounds & Mineral Substances such as Acids, etc. Radioactive substances Oxygen-demanding wastes Plant Nutrients Sediments Thermal Discharges

Examples of Polluted Waters

A very personal look at water What happens to your water before you drink it? What happens to your water after you dispose of it? –Approximately 99% of Swedes are served by wastewater treatment plants, 86.5% of Germans, 74% of Americans, and 57% of Canadians.

What constitutes quality drinking water? Free of pollutants Tastes good –Want Sodium Bicarbonate and Calcium Sulfate in same concentrations as found in saliva –10 o C –As little chlorination as possible Calcium & magnesium account for most water hardness, death rates (cardiovascular disease) higher in soft water areas than in hard water areas Copper needed to absorb & metabolism iron, but >1mg/liter makes water unpalatable Does taste correlate with presence of toxic compounds?

Forms of Pollution – Details Inorganic – acids, salts, toxic metals One gram of lead in 20,000 liters of water makes it unfit for drinking. Lead is often found in the pipes of older homes What is the safe drinking water limit for arsenic? For lead? How much does UA water supply have?

Forms of Pollution – Details Organic: sewage, pesticides, plastics, etc. One drop of oil can render up to 25 liters of water unfit for drinking One gram of 2,4 D can contaminate 10 million liters of drinking water! One gram of PCBs can make 1 billion liters of water unsuitable for freshwater aquatic life!

Acid Precipitation: When Air Pollution Becomes Water Pollution

When the pH drops below 6.0 species start to die off. When one species dies, others that depend on it may as well Acid Rain Effects – Aquatic Systems

Acid Neutralization How does this work? Cation Exchange on clay minerals Role of chemical weathering...

How does acid kill the fish? One way is mobilizing metals When all base cations are striped from soils Acid now reacts with metals e.g. aluminum –Normally aluminum is immobile –below pH 5 - mobile aluminum Fish breath in the water –Aluminum comes out of solution –Clogs gills - suffocate

More Examples: Oxygen and Water Biochemical Oxygen Demand – What does this mean? –Anything in the water that bacteria can break down. –Bacteria will use up oxygen in the water –Other aerobic organisms will die

Oxygen and Water What else can affect the amount of O 2 in the water? –Temperature –Speed of water flow –Roughness of surface over which water flows

Stories about particular pollutant forms: Oil Both Point and Nonpoint Sources Largest source of oil pollution is pipeline leaks and runoff –61% ocean oil pollution river & urban runoff –30% intentional discharges from tankers –5% accidental spills from tankers

Stories about particular pollutant forms: Detergents The nitrates in fertilizers promote excessive growth of algae and larger aquatic plants, causing offensive algae blooms and driving out sport fish. Phosphates are often thought to culprit, nitrogen is the “limiting factor” in most aquatic systems.

Stories about particular pollutant forms: Sediments THE largest form of water pollution Erosion is source – we’ve sped up rate of erosion, e.g. during urban construction can lose up to 43 tons of topsoil/acre/year Natural rates of erosion: leads to aquatic succession

Succession in Aquatic Habitats Lake Sediments & Nutrients Accumulate Oligotrophic Eutrophic Low in nutrients High in nutrients Can sometimes see Methane gas bubbling up From sediments – process of decomposition

Stories about particular pollutant forms: thermal pollution 26% of all water in U.S. is affected by this Up to a point of adding heated water, you can get thermal enrichment Adding more heat, you get thermal pollution

We can also have cold water pollution In many areas fish and Other river organisms are Adapted to relatively warm water. Building a dam results in very cold water released Downstream killing organisms and changing species

A special case: Groundwater What forms of pollution can affect groundwater? All of them except thermal pollution! Renewal time of groundwater is important –Rivers: days –Soil Moisture: 280 days –Groundwater: 300 years

Groundwater doesn’t stay in one place

Oil Well Drilling & Groundwater

Oil Drilling Protocols Well must be cased from surface to below freshwater zone Casing must also be for 150 feet above pay zone Logging apparatus must be retrieved

Oil Drilling Protocols Drilling fluids must be disposed of properly – e.g. no Midnight Haulers Any spills must be reported and cleaned immediately Area will be subject to remediation efforts

Identifying Sources of Pollutants to the Chesapeake Bay We are going to do the same analysis that scientists did in 1998 to determine what some of the major sources of pollutants were to the Chesapeake Bay