Chapter 14 - Environmental Health and Toxicology Flashcards
toxicant
a substance that acts as a poison to humans or wildlife
toxicity
the degree to harm a chemical substance can inflict
toxicology
the scientific field that examines the effects of poisonous chemicals and other agents on humans and other organisms
toxin
a toxic chemical stored or manufactured in the tissues of living organisms. for example, a chemical that plants use to ward off hervibors or that insects use to deter predators
environmental toxicology
the study of toxicants that come from or are distributed into the environment, including the study of health effects on humans, animals, and other ecosystems
mutagen
a toxicant that causes mutations in the DNA of organisms
teratogen
a toxicant that causes harm to the unborn, resulting in birth defects
carcinogen
a chemical or type of radiation that causes cancer
allergen
a toxicant that over activates the immune system, causing an immune response when one is not necassary
endocrine disrupters
a toxicant that interferes with the endocrine (hormone) system
pathway inhibitor
a toxicant that interrupts vital biochemical processes in organisms by blocking one or more steps in important biochemical pathways. compounds in the herbicide atrazine kill plants by blocking key components in the process of photosynthesis
neurotoxin
a toxicant that assaults the nervous system. neurotoxins include heavy metals, pesticides, and some chemical weapons developed for use in war
acute exposure
exposure to a toxicant occurring in high amounts for short periods of time
chronic exposure
exposure for ling periods of time to a toxicant occurring in low amounts
bioaccumilation
the buildup of toxicants in the tissues of an animal
biomagnification
the magnification of the concentration of toxicants on an organism caused by its consumption of other organisms in which toxicants have bioaccumulated
case history
medical approach involving the observation and analysis of individual patients
epidemiological study
a study that involves large-scale comparisons among groups of people, usually contrasting a group known to have been expected to some toxicant and a group that has not
dose response analysis
a set of experiments that measure the response of test animals to different doses of toxicants. the response is generally quantified by measuring the proportion of animals exhbiting negative effects
dose
the amount of toxicant a test animal recieves in a dose response test
response
the type or magnitude of negative effects on animal exhibits in response to a dose of toxicant in a dose-response analysis
threshold dose
the amount of a toxicant at which it begins to affect a population of test animals
LD50 (lethal dose-50%)
the amount of a toxicant it takes to kill 50% of a population of test animals
ED50 (effective dose-50%)
the amount of a toxicant it takes to affect 50% of a population of test animals
dose response curve
a curve that plots the response of test animals to different doses of a toxicant, as a result of dose-response analysis
synergistic effects
a interactive effect (as of toxicants) that is more than or different from the simple sum of their constituent effects
risk assessment
the quantitative measurement of risk, together with the comparison of risks involved in different activities or substances
risk management
the process of considering information from scientific risk assessment i light of economic, social, and political needs and values, in order to make decisions and design strategies to minimize risk
risk
the mathematical probability that some harmful outcome (death, environmental or economic loss) will come from a given action, event, or substance
REACH (registration, evaluation, authorization,and restriction of chemicals)
program of the EU that shifts the burden of proof for testing chemical safety from national governments to industry and requires that a chemical substance produced over 1 metric ton per year be registered with the new European chemical agency REACH
toxic substances control act
a 1976 US law that directs the environmental protection agency to monitor thousands of industrial chemicals and gives the EPA authority to regulate and ban substances that pose excessive risk
