pesticides, Odra River basin, contact toxicity test, Eisenia foetida, acetylcholinesterasa

Effective pesticide substances get into surface waters mostly when they are applied on arable lands. The real situation was verified with passive sampling methods indicating the presence of substances in the environment showing higher sensitivity than the individual point sampling. We used for that the low-cost semipermeable membranes. We determined the pesticide conxentration in the extract by the method of gas chromatography. In the case of sediment samples, we determined the acute toxicity by the contact toxicity test with the use of earthworms Eisenia foetida. The resulting assessment criterion was the determined mortality with LC 50. The earthworms which passed the acute toxicity test without observed lethality were then made subject to the test determining inhibition of the enzyme of acetylcholinesterasis.