Approaches to Pollution Management Complete #5 on the worksheet

Toxicology and Trash

Toxicology Toxicology—measure of how harmful a substance is Potential harm is dependent on Dosage Bioaccumulation—some molecules are absorbed & stored in specific organs or tissues at levels higher than normally would be expected Biomagnification—levels of some toxins in the environment are magnified as they pass through a food web DDT, PCBs, & some radioactive isotopes Chemical interactions that can decrease or multiply the effects of a toxin

Toxicology Poison—chemical that has an LD50 of 50 mg or less per kg of body weight LD50—median lethal dose The amount of chemical that in one dose that kills exactly 50% of the animals in a test population within a 14 day period

Toxicology Toxicity Testing Dose-response curves—shows the effects of various dosages of a toxic agent on a group of test organisms X-axis plot concentration of toxin & y-axis plots response Usually follows an S-shaped curve

Toxicology LD50 Practice

Solid and Hazardous Waste

Love Canal Between 1842-1953, Hooker Chemical sealed multiple chemical wastes into steel drums and dumped them into an old canal excavation. In 1953, the canal was filled and sold to Niagara Falls school board for $1. The company inserted a disclaimer denying liability for the wastes.

In 1957, Hooker Chemical warned the school not to disturb the site because of the toxic waste. In 1959 an elementary school, playing fields and homes were built disrupting the clay cap covering the wastes. In 1976, residents complained of chemical smells and chemical burns from the site.

President Jimmy Carter declared Love Canal a federal disaster area. The area was abandoned in 1980.

Love Canal sparked creation of the Superfund law (CRCLA), which forced polluters to pay for cleaning up abandoned toxic waste dumps. It reminds us that: a) we never really throw anything away b) wastes often do not stay put c) preventing pollution is much safer and cheaper than trying to clean it up! Video (11min)

Superfund Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) - 1980 Identifies abandoned hazardous waste dump sites Protects and cleans up groundwater near such sites Cleaning up the hazardous chemical at the site Requiring responsible parties to pay for the cleanup When no responsible party can be found, EPA draws money out of the Superfund for cleanup 25% of cleanups have been paid for by the superfund

Superfund The Superfund law was designed to have polluters pay for cleaning up abandoned hazardous waste sites. Only 70% of the cleanup costs have come from the polluters, the rest comes from a trust fund financed until 1995 by taxes on chemical raw materials and oil.

Waste Solid waste: any unwanted or discarded material we produce that is not a liquid or gas. Municipal solid waste (MSW) “garbage”: produce directly from homes. Industrial solid waste: produced indirectly by industries that supply people with goods and services. Hazardous (toxic) waste: threatens human health or the environment because it is toxic, chemically active, corrosive or flammable.

The United States produces about a third of the world’s solid waste and buries more than half of it in landfills. About 98.5% is industrial solid waste. The remaining 1.5% is MSW. About 55% of U.S. MSW is dumped into landfills, 30% is recycled or composted, and 15% is burned in incinerators.

Recycling Primary (closed loop) recycling: materials are turned into new products of the same type (aluminum cans, newspaper) Secondary recycling: materials are converted into different products. Used tires shredded and converted into rubberized road surface. Newspapers transformed into cellulose insulation.

Recycling Advantages Disadvantages Reduces pollution Saves energy Reduces mineral demand Reduces greenhouse gas emissions Reduces solid waste Important part of economy Disadvantages May lose money for items such as glass and most plastics Reduces profits from landfills or incinerators Source separation is inconveinent

Burning Solid Waste Globally, MSW is burned in over 1,000 large waste-to-energy incinerators, which boil water to make steam for heating water, or space, or for production of electricity. Japan and a few European countries incinerate most of their MSW.

Waste Incineration Advantages Disadvantages Reduces trash volume Less need for landfills Less water pollution Concentrates hazardous material into ash Sale of energy reduces cost Modern controls reduce air pollution Disadvantages Expensive to build Costs more than hauling to a landfill Difficult to site because of citizen opposition Some air pollution Output approach that encourages waste production

Sanitary MSW Landfill

Landfill Design The bottom liner - layers of clay or other synthetic material (clay, plastic, or composite) placed on compacted soil. The bottom of the landfill is sloped and pipes along the bottom collect leachate. The leachate is then pumped away and treated at a plant.

Landfill Design Trash is dumped onto the landfill and consistently layered with soil to promote safer and better decomposition. A cover is placed over the landfill to keep water out (to prevent eventual leachate formation). Landfills also must have a system to dispose of methane gas.

North Wake Landfill (Now Closed)

Landfills Advantages Disadvantages No open burning Little odor Built quickly Low operating costs Can handle large amounts of waste Land can be used for other purposes Disadvantages Noise and traffic Dust Groundwater contamination Slow decomposition Discourages recycling, reuse, and waste reduction

Hazardous Waste Long-Term Storage Hazardous waste can be disposed of on or underneath the earth’s surface, but without proper design and care this can pollute the air and water. Deep-well disposal: liquid hazardous wastes are pumped under pressure into dry porous rock far beneath aquifers. Surface impoundments: excavated depressions such as ponds, pits, or lagoons into which liners are placed and liquid hazardous wastes are stored.

Long-Term Storage Long-Term Retrievable Storage: Some highly toxic materials cannot be detoxified or destroyed. Metal drums are used to stored them in areas that can be inspected and retrieved. Secure Landfills: Sometimes hazardous waste are put into drums and buried in carefully designed and monitored sites.

Secure Hazardous Waste Landfill In the U.S. there are only 23 commercial hazardous waste landfills.

Brownfields Brownfields are abandoned industrial and commercial sites that are contaminated (e.g. factories, old landfills, gas stations). 450,000 – 600,000 sites exist in the U.S., many of them in economically stressed inner cities. Many of these sites can be cleaned up and reborn as parks, athletic fields and neighborhood.

U.S. Hazardous Waste Regulations Two major federal laws regulate the management and disposal of hazardous waste in the U.S., RCRA and CERCLA: Resource Conservation and Recovery Act (RCRA) – 1976, 1984 Requires EPA to identify hazardous wastes & set standards for their management Primary goal - protect human health and environment from the potential hazards of waste disposal. Calls for conservation of energy and natural resources, reduction in waste generated, and environmentally sound waste management practices.

A Few Stats……. 60 to 80% of solid and hazardous waste produced could be eliminated through a combination of waste reduction, reuse, and recycling. 5% of MSW is recycled or composted while 35% could be. Video: Story of Stuff (20 min)