Initial Environmental Assessment: Plant Protection - Series no 13 (NORAD, 1995): Part I: General account: 3 Possible environ mental impacts: 3.3 Pollution of water

Initial Environmental Assessment: Plant Protection - Series no 13 (NORAD, 1995)

Part I: General account

3 Possible environ mental impacts

		(introduction...)
		3.1 Unintended spreading by air
		3.2 Unintended spreading on or through the soil
		3.3 Pollution of water
		3.4 Impacts of slow degradation in the soil
		3.5 Impacts on flora, fauna and vulnerable ecosystems
		3.6 Health problems
		3.7 Impacts on local communities, traditional ways of life and utilisation of natural resources

3.3 Pollution of water

Pesticide residue in water can cause serious pollution, both of ground water as well as of surface water. In most industrialised countries, the criteria for high water quality insist that water should not contain more than 0.1 ppm of any single pesticide, or a total of 0.5 ppm of pesticides. In some watercourses in agricultural areas, there can be concentrations of a single pesticide which far exceed this limit. A heavy rain shower immediately after spraying can result in pesticide pollution of the water, and this can cause the death of fish and also have other ecological impacts. Research shows that concentrations as low as 1 ppm can change biodiversity in the plant plankton in lakes. Before planning pesticide spraying treatment, one must check whether there are important water sources in the area, and if there is a risk of water pollution. (See also chapter 3.2 above.)