POLLUTION MANAGEMENT

5.4 Eutrophication

Assessment Statements 5.4.1 Outline the processes of

eutrophication. 5.4.2 Evaluate the impacts of

eutrophication. 5.4.3 Describe and evaluate pollution

management strategies with respect to eutrophication.

5.4.1 Outline the processes of eutrophication.

Eutrophication refers to the nutrient enrichment of streams, ponds, and groundwater.

It is caused when increased levels of nitrogen or phosphorus are carried into water bodies.

It can cause algal blooms, oxygen starvation, and eventually the decline of biodiversity in aquatic ecosystems.

Phosphorus in the form of phosphates often come from domestic detergents

5.4.1 Outline the processes of eutrophication.

Nitrogen often comes from burning of fossil fuels or from fertilizers applied to soil

Eutrophication involves: Increase in nitrates and

phosphates in water Rapid growth of algae Light blocked from

submerged aquatic plants Accumulation of dead

organic matter Increased activity of

decomposers Increased removal of

oxygen by decomposers Reduced oxygen kills fish

and other organisms

5.4.2 Evaluate the impacts of eutrophication.

Main reasons high concentrations of nitrogen in rivers and groundwater are a problem:

Nitrogen compounds can cause undesirable effects in the aquatic ecosystems, especially excessive growth of algae.

Loss of fertilizer is an economic loss to the farmer.

High concentrations of nitrates in drinking water may increase stomach cancer and blue baby syndrome (due to insufficient oxygen in the mother’s blood for the developing baby) rates.

5.4.3 Describe and evaluate pollution managements strategies with respect to eutrophication.

Main ways of dealing with eutrophication: Altering human activities, regulating and reducing the nutrient source, clean up strategies.

Altering the human activities that produce pollution by using alternative types of fertilizer, detergent, etc.:

Avoid using nitrogen fertilizers between mid-September and mid-February.

Use autumn-sown crops. Sow autumn-sown crops as

early as possible and maintain crop cover thru autumn and winter.

5.4.3 Describe and evaluate pollution management strategies with respect to eutrophication.

Use split applications to obtain the best match of nitrogen supply and demand and reduce risk of nitrogen loss; cereals March, Grass monthly

Do not apply nitrogen next to headlands.

Use less nitrogen if previous year was dry.

Do not plow up grass. Use steep slopes for

pasture, and flat lands for crops.

Incorporate straw into the soil

Direct drilling and minimal cultivation reduce nitrogen loss by up to half.

5.4.3 Describe and evaluate pollution management strategies with respect to eutrophication.

Regulating and reducing pollutants at sewage treatment plants:

Perform phosphate stripping (caused to precipitate out) on sewage treatment

Use zero/low-phosphorus detergents

Full loads in washing machines

Wash vehicles on porous surfaces away from drains or gutters

Use less fertilizers on gardens

Compost garden and food waste

Collect and bury pet feces

5.4.3 Describe and evaluate pollution management strategies with respect to eutrophication.

Clean up and restoration of polluted water by pumping mud from eutrophic lakes:

Precipitation (Treatment to precipitate phosphates)

Removal of nutrient-enriched sediments like mud pumping

Removal of biomass and using it for thatching or fuel

Prevention is better than treating as it is far more technically feasible, cheaper, and provides better products