In the paper toxicity assessment of hospital wastewaters samples was performed using direct-contact

tests consisting of five species, which represent three different trophic levels of the food chain. IC50 or EC50 values were estimated for each tested organism: Pseudokirchneriella subcapitata IC50/72h 18.77%, Daphnia magna

EC50/48h 20.76%, Thamnocephalus platyurus EC50/24h 22.62%, Artemia salina EC50/24h 59.87% and Vibrio fisheri

EC50/15min 46.17%. Toxic potential of hospital wastewater was described using a system of wastewater toxicity

classification. The toxic units (TU) values estimated for each test indicate that hospital wastewaters are toxic

(Class III). The variable results of the tests’ sensitivity confirmed the need of application of microbiotests battery with organisms of different trophic levels.