Summary:

The study presents the characteristics of the catchment of Trzemna (Ciemna) River from the point of view of the likelihood of appearance and migration of biogenes. A climatological, hydrological and soil characteristics was prepared. Agricultural changes as well as changes in the water and sewage management system and waste management were analysed. Basing on the analyses of WIOŚ the author evaluated, among others, the changes in the concentration of total nitrogen, nitrates, total phosphorus and phosphates in the last few years. The changes in the content of nitrogen and phosphorus in the waters of Trzemna River were evaluated, taking into consideration the natural environment, as well as social and economic changes. The water of the Trzemna River, what is characteristic of it, has high phosphorus and nitrogen concentration. The highest concentration of nitrates is marked from January to May, in the period of rich plants growth it lowers visibly. In the cross-section of Szkudła the nitrate nitrogen form dominates, below the reservoir Gołuchów the concentration of organic and ammonium nitrogen raises, in the cross-section of Tursko, which is situated below the sewage drop from the treatment plant in Gołuchów, nitrates are less than 50% of the total nitrogen, noticeably, the concentration of different forms of nitrogen than nitrate nitrogen raises. In the case of phosphates concentration, the negative influence of the treatment plant on the quality of the Trzemna waters is easily visible; below the treatment plant the concentration of phosphates reaches the record level – phosphate form is 72-83% of the total phosphorus. The Trzemna waters are classified as fifth-class quality. The research undertaken by WIOŚ (VIEP – Voivodship Inspectorate for Environmental Protection) confirms that there is no tendency to improve their quality.