Upload
norma-norton
View
224
Download
6
Tags:
Embed Size (px)
Citation preview
CHAPTER 17HUMAN HEALTH AND ENVIRONMENTAL RISKS
THREE CATEGORIES OF HUMAN HEALTH RISKS
PHYSICAL – EXCESSIVE EXPOSURE TO UV RADIATION OR RADON
BIOLOGICAL - ASSOCIATED WITH DISEASE
CHEMICAL – NATURALLY OCCURRING AS WELL AS SYNTHETICALLY PRODUCED
LEADING CAUSES OF DEATH IN THE WORLD
BIOLOGICAL RISKS
INFECTIOUS 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 INCREASE PANDEMIC – EPIDEMIC OVER A LARGE
GEOGRAPHIC AREA
LEADING HEALTH RISKS
HISTORICAL DISEASES
PLAGUE – AKA BUBONIC PLAGUE OR BLACK DEATH CAUSED BY BACTERIA SPREAD BY FLEAS MOST RECENT PANDEMIC IN ASIA IN EARLY 1900’S
MALARIA CAUSED BY A PARASITIC PROTIST CARRIED BY MOSQUITOES
TUBERCULOSIS CAUSED BY AIRBORNE BACTERIA SERIOUS PROBLEM TODAY IS DRUG-RESISTANT STRAINS
EMERGENT DISEASES HIV/AIDS – SPREAD BY CONTACT WITH
INFECTED BODILY FLUIDS
EBOLA – EXTREMELY HIGH DEATH RATE
MAD COW DISEASE – CAUSED BY PRIONS; SPREAD TO HUMANS THROUGH INGESTION OF INFECTED MEAT
BIRD FLU – AKA H1N1; SPREAD FROM INFECTED DOMESTICATED BIRDS
WEST NILE VIRUS – SPREAD FROM WILD BIRDS TO HUMANS VIA MOSQUITOES
TRANSMISSION OF PATHOGENS
CHEMICAL RISKS
NEUROTOXINS- CHEMICALS THAT DISRUPT THE NERVOUS SYSTEM – SOME INSECTICIDES, LEAD, MERCURY
CARCINOGENS- CHEMICALS THAT CAUSE CANCER – ASBESTOS, RADON, FORMALDEHYDE, TOBACCO
TERATOGENS- CHEMICALS THAT INTERFERE WITH THE NORMAL DEVELOPMENT OF EMBRYOS OR FETUSES – THALIDOMIDE, ALCOHOL
ALLERGENS- CHEMICALS THAT CAUSE ALLERGIC REACTIONS – PEANUTS, MILK, PENICILLIN, CODEINE
ENDOCRINE DISRUPTORS- CHEMICALS THAT INTERFERE WITH THE NORMAL FUNCTIONING OF HORMONES IN AN ANIMAL’S BODY - HORMONES
DOSE-RESPONSE STUDIES
LD50- LETHAL DOSE THAT KILLS 50% OF THE INDIVIDUALS STUDIES ARE CONDUCTED ON ANIMALS AND EXTRAPOLATED TO HUMANS
ED50- EFFECTIVE DOSE THAT CAUSES 50% OF THE ANIMALS TO DISPLAY THE HARMFUL BUT NONLETHAL EFFECT SUBLETHAL EFFECTS – IS THE CHEMICAL A TERATOGEN, CARCINOGEN, NEUROTOXIN?
LD50 STUDY
SYNERGISTIC 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.
ROUTES OF CHEMICAL EXPOSURE
BIOACCUMULATION
AN INCREASED CONCENTRATION OF A CHEMICAL WITHIN AN ORGANISM OVER TIME
USUALLY OCCURS WITH FAT-SOLUBLE SUBSTANCES
CLASSIC EXAMPLE: DDT
BIOMAGNIFICATION IN THE FOOD CHAIN - DDT
PERSISTENCE
HOW LONG A CHEMICAL REMAINS IN THE ENVIRONMENT
RISK ANALYSIS
PROBABILITY OF DEATH IN U.S.
QUALITATIVE RISK ASSESSMENT
MAKING A JUDGMENT OF THE RELATIVE RISKS OF VARIOUS DECISIONS
PROBABILITY- THE STATISTICAL LIKELIHOOD OF AN EVENT OCCURRING AND THE PROBABILITY OF THAT EVENT CAUSING HARM
QUANTITATIVE 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
STOCKHOLM CONVENTION
IN 2001, A GROUP OF 127 NATIONS GATHERED IN STOCKHOLM, SWEDEN, TO REACH AN AGREEMENT ON RESTRICTING THE GLOBAL USE OF SOME CHEMICALS
12 CHEMICALS WERE TO BE BANNED, PHASED OUT, OR REDUCED
THESE INCLUDE DDT, PCBS, AND CERTAIN CHEMICALS THAT ARE BY-PRODUCTS OF MANUFACTURING PROCESSES.