Małgorzata Bonisławska, Adam Tański, Małgorzata Mokrzycka, Adam Brysiewicz, Arkadiusz Nędzarek and Agnieszka Tórz
Fish farming and especially rearing and breeding of rainbow trout and carp is one of potential sources of surface water pollution. The study was aimed at assessing the effect of a rainbow trout farm on water quality in the Gowienica River in winter. Temperature, pH, electrolytic conductivity, total suspended solids, dissolved oxygen, BOD5, CODCr, alkalinity, water hardness, calcium, magnesium, ammonium-nitrogen, nitrate-nitrogen (III and V) and total phosphorus were determined according to Polish Norms and APHA  in water samples collected in winter up- and downstream the study object. The increment of pollutant concentrations in rainbow trout farm effluents was referred to the requirements in Rozporządzenie MŚ . Performed studies and literature review show that effluents from the assessed fish farm did not worsen water quality of the river. Increased concentrations of total suspended solids and CODCr in effluents were noted only in March. According to data from the report on environmental status in zachodniopomorskie province in the years 2008-2011, poor water quality of the Gowienica River is recorded already upstream the rainbow trout farm. Pollution of this stretch of the river may originate from uncontrolled waste water management and from nutrient runoff from fields.