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Environmental Science: Toward a Sustainable FutureRichard T. Wright Chapter 19 Hazardous Chemicals: Pollution and PreventionPPT by Clark E. Adams
Four Ways to Address Chemical Pollution • Safe disposal • Pollution prevention • Recycling • Treatment
Hazardous Chemicals: Pollution and Prevention • Toxicology and chemical hazards • A history of mismanagement • Cleaning up the mess • Managing current hazardous waste • Broader issues
Toxicology and Chemical Hazards • Dose response and threshold • The nature of chemical hazards: HAZMATs • Sources of chemicals entering the environment • The threat from toxic chemicals • Involvement with food chains
The Nature of Chemical Hazards: HAZMATs • Chemicals That Present Hazard or Risk • Ignitability: catch fire readily; gasoline • Reactivity: unstable and may explode or create toxic fumes when mixed with water; explosives, concentrated sulfuric acid • Toxicity: injurious to health; pesticides, chlorine
Toxics Release Inventory • Emergency Planning and Community Right-to-Know Act (EPCRA) 1986 • Industries must report locations and quantities of toxic chemicals stored on site and releases of toxic chemicals.
Toxics Release Inventory • For 2001: • 1,679 million pounds of toxic chemicals released to the air • 221 million pounds of toxic chemicals released to the water • 4,258 million pounds of toxic chemicals released at land disposal sites • Total environmental release = 6,158 million pounds
The Threat from Toxic Chemicals • Many are broken down by natural processes • Two types persist in the environment • Heavy metals • Synthetic organics
Heavy Metals • Lead, mercury, arsenic, cadmium, tin, chromium, zinc, copper • Used in metalworking, paint, and pesticides, among other products
Heavy Metals • Soluble in water and readily absorbed by body • Interfere with enzyme function • Example: mental retardation from lead poisoning
Organic Compounds • Chemical basis for plastics, synthetic fibers and rubber, solvents, and pesticides • Resistant to biodegradation • Major health effects: carcinogenic and mutagenic
Organic Compounds (see Table 19-1) • Halogenated hydrocarbons • At least one of the hydrogen atoms is replaced with a halogen atom • Chlorine (most common) • Bromine • Fluorine • Iodine
Involvement with Food Chains • Minamata disease • Small fishing village in Japan • Suffered from mercury poisoning • Biomagnification • “Mad as a hatter” • Hatmakers exposed to mercury suffered from insanity
A History of Mismanagement • Methods of land disposal • Scope of the management problem
Methods of Land Disposal • Deep-well injection • Surface impoundments • Landfills
Secure Landfills (see Fig. 19-9) • Properly lined • Supplied with a system to remove leachate • Provided with monitoring wells • Appropriately capped
Toxic Chemical Waste Problems • Cleaning up old wastes • Managing new wastes • Avoiding future wastes
Midnight Dumping and Orphan Sites • Hazardous wastes left on remote or unoccupied properties by unscrupulous haulers. • Companies stored wastes on their own properties and went out of business, abandoning the property and wastes.
Scope of the Mismanagement Problem • The Love Canal story (see Fig. 19-12) • Hooker Chemical and Plastics Company • 17,000 tons of hazardous wastes dumped in abandoned canal • Covered canal with clay cap and sold it to the Niagara Falls school board • People reported serious health problems: birth defects and miscarriages • $233 million spent on cleanup and lawsuits
Problems Concerning Toxic Chemicals • Cleaning up the messes already created • Regulating and handling and disposal of wastes currently being produced • Protect public and environmental health • Reducing the quantity of hazardous waste produced
Cleaning Up the Mess • Ensuring safe drinking water • Safe Drinking Water Act of 1974 • Groundwater remediation • Superfund for toxic sites
Superfund for Toxic Sites • Advanced cleanup technology • Incineration to burn off contaminants in soil • Cleaning soil with detergent • Bioremediation • Phytoremediation • Brownfields • Costly and slow
Managing Current Hazardous Wastes • Clean Air and Water Acts • Resource Conservation and Recovery Act (RCRA) 1976 • Reduction of accidents and accidental exposure
RCRA • All disposal facilities must have permit • Pretreatment of toxic wastes • “Cradle to grave” tracking of toxic wastes
Reduction of Accidents and Accidental Exposure • Leaking underground storage tanks (LUST) • Underground storage tank (UST) legislation • Department of Transportation Regulations (DOT Regs) • Occupational Safety and Health Act (OSHA)
Reduction of Accidents and Accidental Exposure • Emergency Planning and Community Right- to-know Act (EPCRA); also known as Superfund Amendments and Reauthorization Act (SARA) • Toxic Substances Control Act
Broader Issues • Environmental justice and hazardous wastes • Emelle, Alabama • Choctaw reservation in Philadelphia, Mississippi • 870,000 U.S. federally subsidized housing units
Broader Issues • Pollution prevention for a sustainable society • Better product or materials management • Substitution of products for hazardous ones • Cleaning up and recycling solvents and lubricants • Safe disposal