Pollution Flashcards
(47 cards)
Define contamination
The presence of concentrations of substances in water that are above the natural background level for that area
Define pollution
Something done by humans which damages the environment.
The direct or indirect introduction as a result of human activity, of substances or heat into the air, water or land, which may be harmful to human health or the quality of aquatic ecosystems or terrestrial ecosystems directly depending on aquatic ecosystems, which result in damage to material property or which impar or interfere with amenities or other legitimate uses of the environment.
What are the 7 types of pollutants?
(order from least to most hazardous)
Natural inorganic salts and sediments
Waste heat
Organic wastes
Trace metals
Synthetic Organic Chemicals
Radioactive materials
Chemical and biological warfare agents
What causes natural inorganic salt and sediment pollution?
Only becomes a problem in excessive doses - main cause is soil washed off land caused from changes in crop growing practices causing increased land erosion
What are the effects of natural inorganic salt and sediments?
Solid matter increases the turbidity of water and reduces the photosynthesis by reducing light pollution.
When settling at the bottom it smothers plants and animals, preventing spawning of fish and clogging the feeding/respiratory structures of aquatic animals.
What causes waste heat pollution?
Cooling systems in power plants use water to carry away large quantities of heat.
What are the effects of waste heat pollution?
Effects the solubility of oxygen and the speed of chemical reactions. Increase in T causes a decrease in DO which is harmful to aquatic life and water quality.
What causes organic waste pollution?
Domestic sewage which contains mainly carbon, nitrogen and phosphorus.
What are the effects of organic waste pollution?
Nitrates can be dangerous to babies.
Organic matter is oxygen demanding thus reduced DO.
Organic effluents also contain large quantities of SS which reduce light availability and photosynthesis.
How are the effects of organic waste pollution reduced?
Treating and dispersing the effluent into large water bodies.
BOD is reduced by dilution to satisfy natural DO in water body.
What is an organic waste that is directly toxic to aquatic animals?
What are the types and how is this effect worsened?
Ammonia
Un-ionised is far more toxic than ionised.
Increasing temperature and pH will push a greater proportion into the un-ionised (more toxic) form.
What causes trace metals pollution?
Salts of heavy metals are present in the environment naturally in small amount.
There can be toxic quantities in:
- discharges from sewage and industry
- minewater discharges
- atmospheric deposition (from fossil fuel combustion)
- road run-off (additives in fuel and leaching)
- metal containing products
What are the effects of trace metals pollution?
Kill aquatic organisms at very low concentrations
What type of synthetic organic chemicals causes pollution and what is it?
Persistent organic pollutants - a group of toxic organic chemical which persists in the environment for longer than their intended use and are characterised by low water solubility and high lipid solubility.
Why are synthetic organic chemicals a problem?
They are slow to degrade and can be bioaccumulated in the food chain so despite wastewaters containing a low dilution, the food chain can multiply the concentrations, distributing the chemicals across the globe.
What are the 2 types of persistent organic pollutants and give examples of both?
What effects do these have?
Polyaromatic hydrocarbons (PCBs)
Increases mortality and deformations in mammals
- printing inks and paints
- plasticizers
- lubricants
-insulators in transformers
Organophosphorus pesticides (PAHs)
Causes liver damage and is a carcinogen.
- produced via incomplete combustion of organic matter (produced naturally and anthropogenically
- forest fires
-oil seeps
-power generation
-waste incineration
What effects do radioactive material pollution have and how do we reduce these?
Highly toxic over long timescales.
Need to be stored over long time without leakage or contamination.
What effects do chemical and biological warfare agent pollution have and how do we reduce these?
Toxic in very low doses.
Cannot be dispersed without great danger to life.
What is a point pollution source?
Have a definable input point such as a pipe or channel.
What is a diffuse pollution source?
Arise from small or non-point inputs such as runoff or atmospheric deposition.
What are the 8 most common pollution sources?
Continuous sewage discharge
Intermittent sewage discharge
Trade effluent
Leaching from landfills and contaminated land
Urban runoff
Mining
Agricultural run off
Accidents and spillages
How does continuous sewage discharge contribute to pollution?
Contributes degradable organic matter and plant nutrients and microorganisms.
If they contain trade wastes can also contribute metals and organic chemicals.
When does intermittent sewage discharge occur and how does it contribute to pollution?
Sewage system is combined so when there is heavy periods of rainfall the volume of effluent passing through the network increases suddenly. This causes an overflow diluted effluent into the environment.
These discharges contain organic matter, nutrients, and microbiological pollutants.
What do combined storm overflows do?
Act as pressure points in the system which release raw effluent into the environment in the case of heavy rainfall. They prevent STW from being inundated and effluent backing up in the system into people’s homes.
