ENVS10011 Lecture Notes - Lecture 10: Ecotoxicity, Atmospheric Chemistry, Biomagnification
17 May 2018
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WEEK 10: ENVIRONMENTAL POLLUTION
Environmental Pollution: contaminants entering + negatively affecting the environment
• Mainly chemical compounds but sometimes also used physical properties (heat
pollution) or biotic agents
• Main Environmental Types: air pollution, water pollution + soil pollution
• Xenobiotics: compounds that do not naturally occur
o Ecosystems + organisms may have some detoxification capacity – but often
not well equipped to deal with them
Toxicity: negative effect of a contaminant on an organism
Eco-toxicity: negative effect on the environment, an ecosystem
Toxicology: branch of science dealing with these effects
Toxic Effect:
• Dependent on exposure (dose), uptake (amount) + detoxification capacity
• Often assessed by dose – response relationship (LD50 – if more than 50% die)
• Acute (easy to assess) v chronic (difficult to assess, but more important in env.)
Bioaccumulation: concentration of a substance in one particular organism
Biomagnification: concentration of a substance along a food chain in an ecosystem
Synergy: different pollutants together have an amplified effect which cannot be
predicted from their individual effects (usually stronger)
Air Pollution
• More than 2 mil deaths globally per year (may increase by 100,000y due to c.c)
o Main cause: fine particulate matter, then ozone pollution
• WHO (set standards): 1 bil people live where air isn’t safe
• Primary pollutants: directly emitted by a process
o E.g. sulfur dioxide (SO2) (burning brown coal) – accumulating pollutant
• Secondary pollutants: formed by reactions in atmosphere, products of primary
pollutants + atmospheric chemistry
o E.g. Ozone (O3) – non-accumulating (short lived, reactive), only formed in
atmosphere under certain conditions
Emission: point of release of pollutant, emissions often regulated for certain industries
Deposition: input into ecosystem, easily measured for accumulating pollutant
• Dry (gas or solid form) or wet (dissolved in rain rain
Sulfur Dioxide (SO2)
• Accumulating pollutant, primary pollutant – released by burning of fossil fuels which
contain sulphur
• Highly toxic to plants, esp conifer trees
• Main sources: industry, power stations, heatings (coal, oil)
• Forms acid rain, when mixed with water
Desulphurication
- Use clear sulphur – lower sulfur coal + oil
- Methods filter SO2 from exhaust of power stations + industry
- Successful: due to knowing the source and political change (Europe – 1990’s)
Nitrogen Oxides (NOx)
Document Summary
Toxicity: negative effect of a contaminant on an organism. Eco-toxicity: negative effect on the environment, an ecosystem. Toxicology: branch of science dealing with these effects. Bioaccumulation: concentration of a substance in one particular organism. Biomagnification: concentration of a substance along a food chain in an ecosystem. Synergy: different pollutants together have an amplified effect which cannot be predicted from their individual effects (usually stronger) Ozone (o3) non-accumulating (short lived, reactive), only formed in atmosphere under certain conditions. Emission: point of release of pollutant, emissions often regulated for certain industries. Deposition: input into ecosystem, easily measured for accumulating pollutant: dry (gas or solid form) or wet (dissolved in rain rain. Use clear sulphur lower sulfur coal + oil. Methods filter so2 from exhaust of power stations + industry. Successful: due to knowing the source and political change (europe 1990"s) Ozone (o3: an active oxygen species (aos, potent greenhouse gas + very toxic, good in stratosphere, bad in troposphere.
