Eutrophication of water reservoirs under anthropogenic, agricultural and industrial impacts (example of Southern Poland) (original) (raw)

The purpose of the study was to identify the trophic level in retention water bodies located in Southern Poland (Central Europe). Thirty nine different water bodies were selected for study. In order to achieve the objectives of the study, the chlorophyll concentration was measured in the epilimnion layer of these reservoirs throughout the 2012 hydrological year. The water transparency during the summer season was also measured using the Secchi disc method. Based on the chlorophyll content and Secchi disc visibility, the Trophic State Index (TSI) values were calculated for chlorophyll α and Secchi disc visibility (Carlson method) and for chlorophyll α alone (Walker method). Additional measurements included the pH, dissolved oxygen, oxygenation and conductivity of the water. As demonstrated by the analyses conducted in the experiment, the annual average chlorophyll α content varied from approximately 2.5 ug/L in oligotrophic reservoirs (such as for example Pogoria III and Kuźnica Warężyńska), up to more than 70 ug/L in retention reservoirs holding strongly eutrophicated water (i.e. Rozlewisko Bytomki and Żabie Doły N). Water transparency ranged from over 5 m in oligotrophic reservoirs (5.1 m in Pogoria III and 5.5 m in Kuźnica Warężyńska), down to less than 0.5 m in hypertrophic reservoirs (Kamieniec – 0.35 m and Rozlewisko Bytomki - 0.45 m ). Based on the calculated TSI indicators and the classifications found in bibliographic sources covering chlorophyll content, the reservoirs covered by the study were classified according to their specific trophic type. There were three reservoirs classified as oligotrophic and eight as mesotrophic water bodies. There were 28 reservoirs at various stages of eutrophication, ranging from mesoeutrophic (3 reservoirs), eutrophic (18), to water bodies demonstrating seasonal or permanent signs of hypertrophy (7).