Endocrine disrupting compounds (EDCs) have the potential to alter hormone pathways that regulate life processes in humans, vertebrates and invertebrates. Besides xcnobiotics having endocrine effects, there arc naturally occurring estrogenie compounds. The limited number of studies with EDCs in invertebrates is partially due to the fact that their hormonal systems are rather poorly understood in comparison with vertebrates. It is also important, but difficult to discriminate between hormone - mediated and other toxicological modes of action. Data of the potentially adverse impact of EDCs on wildlife species are reviewed.

This paper addresses the issue of antibacterial drugs, estrogens and cytostatic drugs’ presence in

surface waters and their influence on animals. The ecotoxicity and the impact of three active compounds: ciprofloxacin, 17α-ethinylestradiol and 5-fluorouracil on protozoa, crustaceans and fish were examined. Acute

tests (crustaceans’ immobilization test, fish survival test, enzymatic test on Daphnia magna) and chronic tests

(growth test on protozoa, reproduction test on crustaceans and juvenile growth test on two species of fish) were

performed. Acute toxicity studies revealed diversified species - sensitivity to the tested compounds. Crustaceans Artemia salina were the most resistant to all three pharmaceuticals. Fish also demonstrated low sensitivity

to ciprofloxacin and 5-fluorouracil (LC(EC)50-96h > 100 mg/l). In the survival tests, the greatest harm in respect

to fish and crustaceans was demonstrated by 17α-ethinylestradiol, and in the enzymatic tests - by ciprofloxacin.

In all chronic tests, the toxic effects of drugs were proven. Tested compounds limited reproduction of crustaceans and growth of protozoa and fry. The risk assessment, conducted on the basis of the PEC/PNEC quotient,

showed a significant risk in relation to aquatic animals caused by the presence of 17α-ethinylestradiol and

5-fluorouracil in concentrations detected in surface waters.