4 - industrial pollutants Flashcards
heavy metals
a dense metal that is toxic at low concentrations - highly toxic making them a public health concern
six heavy metals
lead - old paints, contaminated water from old pipes
mercury - thermometre liquid, light bulbs
arsenic - pesticides, herbicides
aluminium
cadmium
manganese
clinical effects of heavy metals
dizziness, nausea, pulmonary diseases, GI diseases, impaired voluntary muscle function, anemia, bone deterioration
most significant heavy metals
arsenic, cadmium, chromium, lead
arsenic
heavy metal carcinogen that affects the sulphydryl groups of cells disrupting cell respiration, enzymes and mitosis
heavy metals cause cellular damage via
free radicals (reactive oxygen species)
which population was of big concern for lead poisoning and why
children - they encounter lead through paint chips, water from old pipes, dust, soil, and toys
environmental chemistry
changes in chemical composition beyond a certain limit within the environment, posing health risks to humans
a molecule is the
simplest unit that has the fundamental chemical properties of a covalent compound (ex - H2)
ionic bond
positively and negatively charged ions held together by electrostatic forces
covalent bonds
sharing of electrons between bonded atoms
four chemical reactions
oxidation
reduction
hydrolysis
photolysis
oxidation
loss of an electron, occurs during combustion
relevance of oxidation for environmental public health
used for the treatment of waste water - wastewater aeration - augments the supply of oxygen
reduction
gain of electrons, often involves a reaction with hydrogen
how do redox reactions contribute to pollution control
transform pollutants into less harmful substances via catalytic converters
hydrolysis
split compounds into other compounds using a reaction with water
how is hydrolysis useful for environmental public health
polyethylene tetrapthalate (PET) used in the recycling of plastic
photolysis
decomposition or separation of molecules via lightu
use of photolysis in PH
photocatalysis has the potential to degrade pollutants in the aquatic environment and in waste water
four structural classes of hydrocarbons
aliphatic - straight or branched changes
heterocyclic - ring structure where one member is an element other than carbon
halogenated - hydrocarbons which contain a halogen atom (chlorine, fluorine, bromine) - often used as refrigerants, herbicides, or insecticides
aromatic - benzene ring
aliphatic hydrocarbons
largely from petroleum
additionally, weak anesthetic properties
May also methylate DNA
benzene
completely insoluble in water
Properties of aromatics depend on the substituents added
benzene and polycyclic aromatic hydrocarbons are toxic air pollutants associated with emissions from motor vehicles.
polycyclic aromatic hydrocarbons
result from the incomplete combustion of organic materials
toxic - interfere with enzyme systems and cellular membranes
large scale chemical production can produce the following as a byproduct
persistent organic pollutants:
benzene
trichloroethylene
PAHs
etc
chlorination
an internationally used method to reduce pathogens in drinking water
chlorination byproduct health concern
trihalomethanes have been shown to cause colon cancer and bladder in lab animals, but no causal relationship has been proved yet. The results are highly sex-dependent with men being more likely to be affected, and smoking appearing to play a confounding role
t/f everyone is exposed to low levels of heavy metals from naturally occuring deposits in the earths crust
true
what are some exposure sources for heavy metals
occupational exposure through smelters, coal fired power plantsl leaching from hazardous waste sites
T/F some heavy metals are vital for humans and abundant in nature
true - ex - copper, nickel, and zinc
t/f there is no safe exposure limit to mercury or lead
true
t/f chromium is essential for health in the 3+ state
true, hexavalent is the dangerous format
two types of effects from lead poisoning
cellular and neurological
mechanism of action of heavy metals
they induce exposure to free radicals causing oxidative sterss leading to carcinogenicity, cell membrane damage, and enzyme interference
why are heavy metals a public health concern
human exposure has risen dramatically due to an increase in industrial, agricultural, domestic, and technological applications
natural phenomena which contribute towards heavy metal emissions
volcanic erruptions
cadmium
accumulates in sedimentary rocks and marine phosphates. used in the production of alloys, pigments, and batteries
cadmium toxicity
interacts with calcium and lead to cause osteoporosis and cadmium deposits in bones called hypercalciuria
cadmium disturbs zinc metabolism which inhibits zinc-containing enzymes used in GI absorption
decreases the concentration of copper in the liver and plasma
interacts with iron, decreasing hemoglobin and hematocrit leading to anemia
biggest heavy metal released from industry
chromium
released from industries such as metal processing, tannery facilities, chromate production, etc
human carcinogen
mercury is found in nature in three forms. Which is the toxic one
methyl mercury - its organic form
major source of mercury in the environment
burning of fossil fuels - increasedin the atmosphere and oceans threefold since the pre-industrial times.
fat-soluble methylmercury bioaccumatles in the food chain before being ingested by humans who eat oily fish
minamata disease
results from mercury poisoning
causes atazia, speech problems, paralysis, insanity, coma, death
manganese
beneficial (neuroprotective) in low doses, but in high doses may have harmful neurological complications such as alzheimers and parkinsons as well as mitochondrial dysfunction
three most effective methods to reduce industrial pollutants
legislature
health advice
voluntary agreements - good in principle, less effective in practice
what is the source pathway sink method
source - stop producing harmful byproducts/toxicants
pathway - intervene in the pathway by adding a buffer strip around a crop to reduce the run off of pesticides
rink - advise pregnant women not to eat seafood containing mercury
