PFAS compounds are synthetic chemicals that are persistent in the environment and have been linked to potential health risks. Their presence in water bodies raises concerns about long-term contamination and ecological effects, making their monitoring crucial for effective control.
In early 2025, the Bolmen Research Station initiated a year-long investigation into PFAS concentrations in the southern basins of the lake Bolmen (Figure 1a). The background for this investigation dates back to late 2023 and through 2024, where a study was conducted of PFAS concentrations in Bolmen for Lagan Water Council. Over the course of a year, eight locations were sampled on four occasions, including four inlets, three sites within the main lake, and a nearby small lake, Lillsjön, which discharges into the lake Bolmen and has historically exhibited elevated PFAS concentrations.
Figure 1. (a) The different basins of lake Bolmen. The orange area marks the southernmost basin of Bolmen, here numbered VI. (b) PFAS sampling sites 2025 in around the southernmost basin of Bolmen.
In general, the results indicate that PFAS concentrations were generally low in the main lake, while higher concentrations were detected in Lillsjön (Fig. 2a-b). In particular, PFAS4 and PFOS were among the compounds detected at elevated concentrations. To identify the source of the higher PFAS4 and PFOS concentrations at Lillsjön and to examine their seasonal variations, investigation has been initiated in the two southern basins of Bolmen (Figure 1a, Basin V and VI). The 2025 investigation will involve monthly sampling at seven sites within the basins (Figure 1b).
Figure 2. (a) Measurement results from the samples taken from late 2023 to and during 2024 of PFAS 4 concentrations. The red line shows the new lower limit (4ng/l) of PFAS 4. (b) PFOS levels with limit (0.65 ng/l annual average) in dashed red, continuous lines represent the annual average for each respective location.