4Biological RisksInfectious diseases- those caused by infectious agents, known as pathogens.Chronic disease- slowly impairs the functioning of a person’s body.Acute disease- rapidly impairs the functioning of a person’s body.Epidemic – rapid increasePandemic – epidemic over a large geographic area
6Historical Diseases Plague – aka bubonic plague or black death Caused by bacteria spread by fleasMost recent pandemic in Asia in early 1900’sMalariaCaused by a parasitic protist carried by mosquitoesTuberculosisCaused by airborne bacteriaSerious problem today is drug-resistant strains
7Emergent DiseasesHIV/AIDS – spread by contact with infected bodily fluidsEbola – extremely high death rateMad Cow Disease – caused by prions; spread to humans through ingestion of infected meatBird Flu – aka H1N1; spread from infected domesticated birdsWest Nile Virus – spread from wild birds to humans via mosquitoes
9Chemical RisksNeurotoxins- chemicals that disrupt the nervous system – some insecticides, lead, mercuryCarcinogens- chemicals that cause cancer – asbestos, radon, formaldehyde, tobaccoTeratogens- chemicals that interfere with the normal development of embryos or fetuses – thalidomide, alcoholAllergens- chemicals that cause allergic reactions – peanuts, milk, penicillin, codeineEndocrine disruptors- chemicals that interfere with the normal functioning of hormones in an animal’s body - hormones
10Dose-Response Studies LD50- lethal dose that kills 50% of the individualsStudies are conducted on animals and extrapolated to humansED50- effective dose that causes 50% of the animals to display the harmful but nonlethal effectSublethal effects – is the chemical a teratogen, carcinogen, neurotoxin?
12Synergistic interactions- when two risks come together and cause more harm that one would. Example: the health impact of a carcinogen such as asbestos can be much higher if an individual also smokes tobacco.
19Qualitative Risk Assessment Making a judgment of the relative risks of various decisionsProbability- the statistical likelihood of an event occurring and the probability of that event causing harm
20Quantitative Risk Assessment The approach to conducting a quantitative risk assessment is:Risk= probability of being exposed to a hazard X probability of being harmed if exposed
21Stockholm ConventionIn 2001, a group of 127 nations gathered in Stockholm, Sweden, to reach an agreement on restricting the global use of some chemicals12 chemicals were to be banned, phased out, or reducedThese include DDT, PCBs, and certain chemicals that are by-products of manufacturing processes.