1.5 Humans and pollution

Key Terms• Pollution: The addition of any substance (solid, liquid or gas) or any

form of energy (such as heat, sound, light or radioactivity) to the environment at the rate faster than it can be dispersed, diluted, decomposed, recycled or stored in some harmless form and which has an appreciable effect on the organisms within it.• Point source: The release from a single clearly identifiable siteE.g. a factory chimney, outlet pipes, slurry pits on farms, pipe of swage. (easier to identify and manage)• Non-po

Pollutantsreleased by human activities and may be:• Matter (gases, liquids or solids) which is organic (contains carbon atoms) or inorganic.• Energy (sound, light, heat, radioactivity).• Living organisms (invasive species or biological agents).

Primary pollutants: active upon emissions e.g. carbon monoxideSecondary pollutants: changes after emissions e.g. sulphuric acid

Biodegradable pollutants: do not persist in the environment and break down quickly

(!) photochemical smog is a mixture of primary and secondary pollutants

Major sources of pollutants

Point source and non-point source pollutants

Point source pollutants Non-point source pollutants

Def: The release from a single clearly identifiable site. Def: The release of pollutants from numerous, widely dispersed origins.

Easier to identify. Impossible to detect exactly where it is coming from.

Easier to manage. Air pollution can be blown hundreds of km.E.g. a factory chimney, outlet pipes, slurry pits on farms, pipe of swage…

E.g. vehicle emissions, chemicals spread on fields…

TLAsPOPs Persistent Organic Pollutants

Manufactured as pesticides in the past. Resistant to breaking down and remain active in

the environment for a long time. Can cause significant harm.E.g. DDT Stockolm, 2004 “the dirty dozen” (9 more were added in 2010)

PANs Peroxy AcylNitratesE.g. Photochemical Smogs

PCBs Polychlorinated Biphenyls

DDT Dichlorodiphenyltrichloroethane

VOCs Volatile Organic Compo

• High molecular weight• Not very soluble in water• Highly soluble in fats and lipids –

can pass through cell membranes • Halogenated molecules, often

with chlorine.

OrganicOrganisms are vital in the composting of fields and organic farming• Has become associated with sustainability – as in ‘organic farming’.• When used in terms of pollutants we mean carbon chemistry

organochlorides, organophosphates, plastics, petroleum derivatives.

Acute and chronic pollutionAcute Chronic

When large amounts of a pollutant are released, causing a lot of harm. Swift acting.

Results from the long-term release of a pollutant but in small amounts (over-time)

Often goes undetected for a long time It often spreads widely

E.g. Bhopal disaster, India 1984 Aluminium Sulphate Camel ford in Cornwall 1998

E.g. Minimata methylmercury accumulation in food

chains Air pollution in cities – Beijing 2014 Asbestos dust

Detection and monitoringDirect measurements of air

pollution include measuring:Direct measurements of water or soil pollution include measuring:

Indirect measurements record changes in an abiotic or abiotic

factorThe acidity of rainwater. Nitrates and phosphates. Measuring abiotic factors that

change as a result of the pollutant. e.g. content of oxygen in the water

Amount of gas, for example carbon dioxide, carbon monoxide, nitrogen oxides in the atmosphere.

Amount of organic matter or bacteria.

Recording the presence or absence of indicator species.e.g. polluted conditions – rat-tailed maggot in water) unpolluted conditions – leafy lichens on trees

Amount of particles emitted by a diesel engine.

Heavy metal concentrations.

Amount of lead in the atmosphere.

Actions?1. CHANGE the activity that produces pollution.2. Pass LAW that bans pollutants.3. Clean up - REMEDIATION

The great debate over DDT• Banned in the 70’s following claims in most MEDCs.

Silent spring, over bioaccumulation resulting in eggshell thinning in birds of prey.

• However, it is cheap, and very effective at deterring and killing Anopheles – the Malaria mosquito, Female Anopheles carry the plasmodium parasite which infects red blood cells causing malaria.

• Malaria probably does not receive enough funding for research as it is mostly a disease of the poor.