Status of lakes and streams

New methods needed to capture biological effects

The sharply varying concentrations of pesticides pose a difficulty as regards assessing the risks of damage in water on the basis of a few values. The maximum concentrations arising can be considerably higher than the measured concentrations and the organisms in water are a reflection of the worst case. Another difficulty is that as a rule, a number of compounds occur simultaneously in water and this makes it difficult to assess the combined effect on aquatic flora and fauna.

In order to better and more directly assess the effects of pesticide use on our waters, biological methods need to be developed as a complement to the chemical. The aim of these biological methods is to use analyses of the flora and fauna present  in lakes, rivers and streams to assess whether there is damage due to the toxic action of pesticides. Alternatively, the toxic action of the water and sediment can be studied in the laboratory or in the field. Such methods are now being developed within the CKB programme.