Inorganic pollutants Flashcards
What are inorganic pollutants?
- metals, metalloids
- nitrates, nitrites
- minerals?
- radioactive substances
Naturally occuring inorganic pollutants?
- some are essential for life:
Co, Cu, Fe etc. - some are always toxic (non-essential)
Pb, Cd, Hg
Can inorganic pollutants be destroyed?
No
What about their background concentrations?
Something occurs and we cant do anything about it, but we need to know how much
Adaptation to inorganic pollutants?
Some species can adapt to high concentrations while some die.
List some Potential toxic elements (PTE)!
- Arsenic
- Chromium
- Cobalt
- Copper
- Lead
- Mercury
- Zinc
What are potential toxic elements?
Elements that exhibit metallic properties.
PTE:s are sometimes referred to ‘heavy metals’, what does it mean?
- relatively high density (above 5g/cm^3)
- relatively high atomic weight
- toxic at low concentrations
- cant be destroyed
- widely distributed
What are metals properties?
- accumulates in organisms
- cant be broken down by liver
- persistent in environment
pH effect on metals?
- toxicity depends on pH
- decreased solubility as pH increases -> less toxic
- free ionic form usually most toxic (except aluminum)
Toxicity is pH dependent!
Something about mercury (Hg)?
- most volatile of all metals
- highly toxic in vapor form
- liquid in ordinary temperatures
- liquid mercury itself is not highly toxic
- rarely occurs naturally
Anthropogenic (human made) presence of mercury?
- fossil fuel burning
- waste incineration
- mining
- smelting
Some sources of mercury?
- emissions of mercury vapor from large industrial operations
- unregulated burning of coal and fuel oil
- emissions from batteries, thermometers
- gold and silver extraction from mines
Environmental effects of mercury?
Mercury is normally a problem only where the rate of natural formation of METHYLMERCURY from inorganic mercury is greater than the reverse action.
Methylmercury is the only form which accumulates
Which waters can contain a lot of mercury?
Acidic surface waters can contain significant amounts of mercury.
Low soil pH increases the mobility in soil -> water ecosystems in danger
Other environmental effects of mercury (bio) ?
Bioaccumulation:
- increase in concentration of a pollutant from the environment to the first organism in a food chain
Biomagnification:
- increase in concentration of a pollutant from one link in a food chain to another.
Health effects of mercury (ways)?
Toxicity in all forms:
MeHg > vapor > Hg2+ > liquid
Liquid is readily excreted Hg2+ affects liver and kidneys Vapor Hg diffuses from lungs to bloodstream to brains Methylmercury: lipophilic (soluble in fatty tissues) Converted to Hg2+ in brain (neurotoxin)
Health effects of mercury?
- skin burns
- irritation of nose and skin
- rashes
- damage to kidneys
- damage to vision
- loss of hearing and muscle coordination
- severe brain damage
- CNS dysfunction
Something about lead (Pb)?
- melting point of 327 C
- commonly used in the building industry for roofing, flashing and soundproofing
- when combined with tin, it forms a solder, used in electronics and other applications to make connections between metals
- used in batteries, paints and ceramics
- in foods, soft drinks and wine
- application with gasoline
- industrial processes
Chemistry of lead?
Exists in Pb2+ form (PbS is highly insoluble)
PbO (batteries), PbCO3, PbS, PbCl
The solubility of lead compounds in water is a function of?
- pH
- hardness
- salinity
Solubility is highest in soft, acidic water
Significant fraction of lead carried by in undissolved form
Lead, chimistry + soil?
The sink for lead is the soil and sediment
- strongly absorbed to soil
- generally retained in the upper layers of soil
- does not leach appreciably into the subsoil and groundwater
Environmental effects of lead?
- bioaccumulates in the bodies of water- and soil organisms
- health effects can take place in low concentrations
- soil organisms are suffered from lead poisoning
- plants and animals may bioconcentrate lead
Health effects related to lead?
- lead can enter fetus through the placenta of a mother
- transferred from breast milk -> serious damage to nervous system and brain of unborn child
- lowered IQ in children
- behavioral disruptions in childen
More health effects related to lead?
- rise in blood pressure
- kidney damage
- miscarriages
- nervous system and brain damages
- death, with high levels
Something about cadmium?
- most toxic in its ionic form (unlike mercury, vapor)
Greatest source of cadmium? Greatest application?
- from our food supply-seafood, organ meats, potatoes, rice and other grains
- greatest application in batteries
Environmental effects of cadmium?
Longe range transportation when absorbed by sludge
- it pollutes surface waters as well as soils
Strongly adsorbs to organic materials in soils
Why cadmium can be extreme dangerous in soils?
- its uptake through food will increase
- low pH enhance cadmium uptake by plants -> accumulated in plants
Health effects of cadmium?
- kidney- and lung toxicity
- skeletal effects
- osteoporosis and osteomalacia
- cancer
Something about chromium?
- steel-gray solid, high melting point
- occurs in the environment in two valance states:
- trivalent chromium (III)
- hexavalent chromium (IV) more toxic!
Difference between chromium III and IV?
III:
- in an organic form is an essential micronutrient for life
- shortages cause cause health problems, uptake a bit too
IV:
- powerful epithelial irritant
- carcinogenic
- toxic to many plants, aquatic animals and bacteria
Sources if chromium?
- naturally occurs in rocks, plants, animals, soil, and volcano dust and gases Natural sources of Cr: - weathering of rock constituents - wet precipitation - dry fallout from atmosphere
Environmental effects of chromium (pathways)?
- the atmosphere is a major pathway for long-range transfer
- most of the chromium in the air will settle and end up in waters or soil
- in water, chromium will absorb on sediment and become immobile
- in soils chromium strongly attaches to soil particles and as a result it will NOT move towards groundwater
Environmental effects of chromium III and IV?
- Cr (III) is generally not transported over great distances because of its low solubility and tendency to be adsorbed by soil particles
- Cr (IV) most mobile in water and soil
- Conversion from III to IV increases Cr dislocation from soil to water systems
Health effects of chromium?
- chromium (IV) is a danger to human health mainly for people who work in the steel and textile industry
- smokers have a higher chance of exposure to chromium
- all other stuff
Something about arsenic?
- widespread in the environment, human activity has mobilized it
- found naturally in the Earth’s crust
- odor- and colorless
- organic or inorganic compounds
- NOT easily water soluble
Sources of arsenic?
Atmosphere: - volcanoes, burning of fossil fuels - commercial or industrial processes Smelting of metals Pharmaceutical industry etc.
Environmental effects arsenic?
- runoff through surface- and groundwater
- accumulates in plants if soil conditions are right
- bioaccumulates in aquatic ecosystems
Health effects on arsenic?
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