Exam 3 Flashcards
(24 cards)
silent killer, the smog killed 12,000 in 4 days and an estimated further 8,000 died from ill health caused by the fog in the months after it
London smog winter 1952
what lead to the Clean Air Act of 1952 in Britain?
air pollution from industry and household coal burning
burning of fossil fuels in power stations, car exhaust, industrial emissions, waste disposal are all sources of what?
air pollution
composition and dispersion of air pollutants under certain climate conditions results in…..
smog
this type of smog comes from high levels of particulates and SO2 via coal burning, results from a combination of incomplete combustion, fog, cool temperatures
reducing smog
this type of smog comes from high levels of O3, NOx, HC, results from car exhausts in bright sunlight, made worse by temperature inversion (pollutants can’t escape, effect of pollutants magnified)
photochemical-oxidant smog
levels > 0.05 ppm cause increased incidence of respiratory illness, levels > 0.2 ppm increased mortality, smoke has a synergistic effect with this compound, reacts with atmospheric water to form sulfuric acid/acid rain, asthmatics are very sensitive to this compound
sulfur dioxide (SO2)
protects us from UV radiation when it is up in the stratosphere, “good up high bad nearby”, longer exposures to this compound decrease respiratory function, irritates the lungs of asthmatics at 50 ppb, also damages plants through contact exposure
ozone (O3)
this compound originates from car exhaust, causes respiratory symptoms at 5-10 ppm, deep lung irritant (at alveolar level)
nitrogen dioxide (NO2)
binds to hemoglobin and reduces the ability of the blood to supply O2, chronic exposure may cause heart damage due to tissue anoxia, high concentrations of this in heavy traffic cause dizziness, headache, lassitude, found in cigarette smoke, increase in mortality and hospital admission for cardiovascular disease with no threshold
carbon monoxide (CO)
solid particles (like soot) in suspended air, smaller diameter of particle greater amount of penetration into the lung
particulate matter (PM)
this size particulate matter can penetrate into at least the larynx, produced by suspensions of dust from construction or agricultural operations, burning of fossil fuels, crushing or grinding, coal or cement dust, fly ash, linked with asthma
inhalable coarse PM (2.5 - 10 micrometers, PM10)
this size particulate matter is derived from fossil fuel combustion, burning of vegetation, metal smelting, tobacco smoke, composed of PAHs and metals, reach the lung alveoli and can be absorbed
fine PM (0.1 - 2.5 micrometers, PM2.5)
dry and wet precipitation of sulfuric and nitric acids, acids removed from air by washout or rainout, causes water pollution, direct damage to leaves of trees, acidification of the soil and release of toxic metals, loss of elemental elements like Mg from the soil, soils with poor buffering capacity are affected more, even if soils are buffering heavy rainfall leads to acidic water saturating the system, this runoff with NH4SO4 fertilizers causes rivers and lakes to become more acidic, toxic metals (Cd, Pb) leach out from soil, Al salts dissolve in water, increased fish mortality, decreased root growth
acid rain
tetraethyl ______ added to gasoline, biggest source up to the 1970s, concern about the health and environmental effects of this, EPA started phasing out gas with this in 1974 overcoming legal battles with refiners, urban air and blood concentrations of this consequently decreased, current sources of this include industrial processes, paint in old houses, batteries, cigarette smoke, cooking vessels with glaze made with this, biochemical effects seen at very low levels of this, subclinical toxicity (not showing symptoms, labs may not show any abnormalities), systems affected (CNS, heme synthesis, bone formation, kidney function), young children particularly susceptible to effects of this molecule, organic type of this more toxic - absorbed through the skin
lead
biomarkers of lead toxicity, high exposure - will find hemoglobin and erythroporphyrin in urine (usually from occupational exposure), low exposure - increased excretion of ALA in urine, ALAD inhibition, lower ALAD ratio means higher lead exposure
effects of lead on heme synthesis
sources - groundwater, metal ore mining, pesticides, chronic exposure leads to hyperpigmentation of the skin, keratosis (excessive production of keratin), cancer, black foot disease, inorganic type of this is more toxic than organic form (found in seafood)
arsenic
these cause endocrine changes in organisms and their offspring, endocrine system maintains homeostasis and longer term control by means of chemical signals called hormones, examples are estrogenic (malathion, BPA, OCs, DDT), androgenic (atrazine, DDT), reproductive (DES, dioxins), thyroidal (PCBs), mechanism of action for estrogenic compounds (mimic the effect of estrogen OR antagonize the effect of estrogens), example of this - male fish produce vitellogenin (VTG) which is a protein that female fish synthesize in response to estrogen, VTG used as a biomarker for the effect of these like ethinylestradiol (EE2)
endocrine disruptors
tributyl tin oxide (TBTO) used to stop fouling of wood in boats, TBTO reaches high levels in harbors and marinas, these animals are very sensitive to this, imposex in females (imposing male characteristics on a female), TBTO interferes with sex hormone metabolism in this animal
mollusks
this pesticide spilled in a lake in Florida in 1980, high levels of this pesticide were found in gator eggs, has both estrogenic and androgenic effects (low testosterone levels in males, abnormal ovarian structure in females), abnormal sexual maturation leads to infertility (population plummets)
DDT
broad spectrum herbicide (weed killer), inhibits amino acid synthesis in plants, used with resistant crops, extensively used in agriculture and lawns, products with surfactants formulated for aquatic use cause developmental and gill toxicity in amphibians and fish, listed as a probable carcinogen and known to the State of California to cause cancer
glyphosate
this molecule exists as three forms (elemental, inorganic salts, organic compounds), elemental and organic readily absorbed leading to CNS toxicity (absorbed through the skin), inorganic not readily absorbed (nephrotoxic), sources of exposure (ore mining, waste incineration, industrial emissions especially coal, medicinals, seafood), cross placental barrier leading to teratogenic effects - fetal red blood cells concentrate this more than adults
mercury
inorganic mercury released in wastewater from factory in Japan 1950s, mercury combined with organic matter to form CH3Hg (methyl mercury) which bioaccumulated in fish and shellfish, chronic exposure to dietary seafood resulted in CNS effects (memory loss, loss of muscle coordination, cerebral palsy)
minimata disease
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