Download Toxicology: Understanding the Harmful Effects of Chemicals and Environmental Health and more Quizzes Environmental Science in PDF only on Docsity! TERM 1 Toxicology DEFINITION 1 study of the harmful effects of chemicals on human and environmental health TERM 2 Integrated Risk Information System (IRIS) DEFINITION 2 EPA data on toxic chemicals is made available though the IRIS TERM 3 Dose Response and Threshold DEFINITION 3 Dose- the level of exposure multiplied by the length of time over which exposure occursResponse- some acute or chronic effects or the development of tumorsThreshold level- level below which no ill effects are observed TERM 4 The Nature of Chemical Hazards DEFINITION 4 Hazardous material (HAZMAT) - a chemical that presents a certain hazard or riskproperties: -ignitability- substances that catch fire easily (gas, alcohol) -corrosivity- substances that corrode material (acids) -reactivity- substances that are chemically unstable and may explode or create toxic fumes when mixed with water (explosives) -toxicity- substances that are injurious to health when they are ingested or inhaled (chlorine, pesticides) TERM 5 Sources of Chemicals Entering the Environment DEFINITION 5 -Total product life cycle- the sun of all steps the manufacturing of a product, from obtaining the raw materials to disposing of the product-800,000+ registered commercial-use chemicals within the US -various chemical products and by products enter the environment, effecting human and environmental health (pesticides, fertilizers, and road salts)-Toxics Release Inventory (TRI)- an annual record of releases of toxic chemicals to the environment including the locations and quantities of toxins stored at US sites TERM 6 The Threat from Toxic Chemicals DEFINITION 6 -A large portion of toxins released into the environment are broken down-2 major classes of chemicals do not degrade in the environment (1)heavy metals - lead, mercury, arsenic, cadmium, tin, chromium, zinc, copper) (2)synthetic organics - plastics, synthetic fibers and rubber, paintlike coatings, solvents, pesticides, wood preservatives) TERM 7 Dirty Dozen DEFINITION 7 -Halogenated hydrocarbons - organic compounds in which one or more of the hydrogen atoms have been replaced by atoms of chlorine, bromine, fluorine, or iodine (halogens) - chlorinated hydrocarbons/ organic chlorides - widely used in plastics, pesticides, solvents, and electrical insulation TERM 8 Methods of Land Disposal DEFINITION 8 3 primary methods-deep-well injection // involves drilling a borehold below groundwater into porous geological formation, injecting the waste, and sealing the bottom-surface impoundments // excavated depressions (ponds) into which liquid wastes are drained and held // least expensive and most common method- landfills // involves sealing concentrated solid and liquid wastes into drums and burying them // 2007 - 403 million lbs of HAZMATS delivered to on-site landfills, 341 million lbs delivered to off-site landfills // 23 US landfills licensed to receive off-site hazardous wastes TERM 9 Mismanagement of Hazardous Wastes DEFINITION 9 -The need for alternative methods to dispose of waste chemicals created an opportunity for a new enterprise- waste disposal-midnight dumping // the act of dumping hazardous wastes in any available location under the cover of darkness, avoiding the disposal fee-orphan sites // hazardous waste sites without responsible party to clean them up TERM 10 Ensuring Safe Drinking Water DEFINITION 10 First priority is to ensure that people have safe water, second is to clean up or isolate the source of pollution so that further contamination does not occur-Safe Drinking Water Act of 1974- the EPA sets national standards to protect the public health// allowable levels of specific contaminants (if there is an exceeding of the max contaminant levels, water is shut down until it is clean- Groundwater remediation // involves drilling wells, pumping out the contaminated groundwater, purifying it, and injecting the purified water back into the ground or discharging it into surface waters
