EVALUATION OF THE WATER EUTROPHICATION LEVEL OF THE GOCZAŁKOWICE DAM RESERVOIR (POLAND, CENTRAL EUROPE)

The aim of the research was to assess the state of eutrophication of the Goczałkowice dam reservoir in 2021 and 2022. The Goczałkowice reservoir is located in southern Poland, in Central Europe. This reservoir has flood control and water supply functions, therefore the purity of its waters is very important. The reservoir is surrounded by numerous agricultural fields and rural areas without a sewage system. This significantly contributes to the increase in the fertility of the reservoir water. The samples for algae research were taken during the vegetation season in 2021 and 2022 during 6 months from two research points (from May to October) – G 1 and G 2. The assessment of the trophic state of studied reservoir parts was based on limit values given by Heinonen for the total phytoplankton biomass and the OECD limit values for chlorophyll a, total phosphorus and total nitrogen. The results of the research regarding the average size of algae biomass in the reservoir water indicate a prevailing meso-/eutrophic (2.96 mg·dm-3 – G 1 and 2.73 mg·dm-3 – G 2 in 2021) and eutrophic state of the water (3.15 mg·dm-3 – G 1 and 2.94 mg·dm-3 – G 2 in 2022) at the studied sites in both years of the research (the boundary values of the phytoplankton biomass for meso- /eutrophy and eutrophy amount to 1.98 mg·dm-3 – 3.45 mg·dm-3 and 3.45 mg·dm-3 – 6.93 mg·dm-3 respectively). The numerous Cyanobacteria (i.a. Microcystis viridis, Aphanizomenon flos-aquae, Planktothrix agardhii), green algae (i.a. Pediastrum boryanum, Coelastrum microporum) and diatoms (i.a. Aulacoseira granulata, Nitzschia acicularis and Nitzschia sigmoidea) have been observed in the reservoir water. These taxa are typical for eutrophic waters. High concentrations of total nitrogen (in the range of 0.57 mg·dm-3 and 1.6 mg·dm-3) and total phosphorus (between 0.034 mg·dm-3 and 0.1 mg·dm-3) allowed the reservoir water in the area of the dam to be classified as eutrophic and periodically hypertrophic, especially in the summer (the boundary values of the total phosphorus and total nitrogen concentrations for eutrophy amount to 0.035 mg·dm-3 – 0.1 mg·dm-3 and 0.6 mg·dm-3 – 1.5 mg·dm-3 respectively). This is particularly dangerous due to the fact that this reservoir is used as a water supply source.

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Opracowanie rekordu ze środków MNiSW, umowa nr POPUL/SP/0154/2024/02 w ramach programu "Społeczna odpowiedzialność nauki II" - moduł: Popularyzacja nauki (2025).