Pollution of Surface Water and Groundwater

Manure (a mixture of faeces and urine) could come into the ground or surface water through:

- Leakage and run-off from animal housing or manure storage;
- Direct discharge of manure on surface water;
- Manure deposits of animals at watering places in streams and rivers
- Run-off from land where manure is applied;Leaching from land which is saturated with nutrients;

The main components of manure in relation to water quality are:

- Minerals mainly Nitrogen and Phosphorus
- Organic matter
- Heavy metals (depending on the origin of manure these could be Cu, Zn or Cd)
- Residues from disinfecting chemicals, crop pesticides and herbicides, and animal drugs;

Nitrogen: Too high concentrations of NO3- in the groundwater make it unsuitable for drinking water. High concentrations of NO3- in surface water lead to eutrophication.

Phosphorus: Phosphorus is not nearly as mobile in the soil as NO3- and therefore much less susceptible to leaching. Nevertheless, leaching of P can occur and if P flows into the groundwater and subsequently in the surface water eutrophication will occur.

Eutrophication: this is caused by an overload of nutrients in surface water and results in an excessive growth of algae, causing oxygen shortage and consequently the death of fish.

Organic matter: High contents of manure organic matter in the surface water causes an-aerobiosis (= an an-aerobic situation) in the water, because the easily decomposable fraction in the manure will start to decompose immediately using all dissolved oxygen and killing the water flora and fauna.

Heavy metals: Heavy metals in manure will cause toxicity and damage and eventually kill water flora and fauna.

Agro-chemicals: Agro-chemical in manure can have a toxic effect on water flora and fauna.

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