Water samples from the Bóbr River and Lake Rakowickie were collected on 24 August 2026. This was an intervention sampling carried out at the request of the Regional Inspectorate for Environmental Protection in Wrocław in connection with heavy rainfall. The analyses were conducted by the accredited Central Research Laboratory of GIOŚ in Wrocław.
The tests were carried out at four sites: in Wrzeszczyn, by the dam in Pilchowice, in Marczów and in Lake Rakowickie.
Lead and mercury detected
The results show that lead was detected in two samples. Its concentration by the dam in Pilchowice was 0.0048 mg/l, while in Marczów it was 0.0053 mg/l. In Wrzeszczyn and Lake Rakowickie, the result was below the lower limit of the measuring range for the method used.
In the same two sites, mercury was also detected. By the dam in Pilchowice, the level was 0.010 µg/l, and in Marczów 0.020 µg/l. In Wrzeszczyn and Lake Rakowickie, mercury was below the lower limit of the measuring range.
The other metals analysed—including chromium, nickel, cadmium and copper—were below the lower limit of the measuring range of the methods used in all four samples.
Most suspended solids by the dam
The tests also revealed significant differences in the total suspended solids content. The highest result was recorded by the dam in Pilchowice—90 mg/l, while in Marczów it was 72 mg/l. For comparison, the result was 12.2 mg/l in Wrzeszczyn and 12.0 mg/l in Lake Rakowickie.
The highest concentration of total phosphorus—0.57 mg/l was also recorded by the dam, while in Marczów it was 0.56 mg/l. The highest level of Kjeldahl nitrogen was likewise found by the dam—2.83 mg/l. In Marczów, it was 1.80 mg/l.
Is the Bóbr contaminated?
The test result alone does not allow such a conclusion. GIOŚ notes that the report refers exclusively to the specific samples collected and presents laboratory results. It does not, however, contain a separate assessment of the water status or a determination of whether it complies with specific environmental standards.
At the same time, it is worth emphasising that the Bóbr is currently subject to enhanced monitoring. GIOŚ conducts tests every two weeks at four sites, and the scope of the analyses has been expanded to include, among other things, additional water-quality indicators.
The latest results therefore confirm the presence of trace amounts of mercury and lead in some of the samples tested. However, they do not automatically mean that the entire river is contaminated with these metals or that applicable standards have been exceeded.