Concerns raised over water safety at Tuusulanjärvi in Finland after wastewater discharge

A recent incident in Tuusulanjärvi, Finland, has raised concerns among local residents about water safety after the discharge of wastewater due to a pump station malfunction at the end of September. Many, including dog walker Mimmi Taajamo, expressed apprehension about swimming in the lake, stating the thought of it is unappealing.

Johanna Mikkonen, an ice swimmer, shared her decision to refrain from swimming this winter but may reconsider next summer. Currently, swimming is still advised against at various beaches, including Tervanokka and Vanhankylänniemi. However, Jaana Hietala, an environmental planner from the Central Uusimaa Environmental Centre, reassured the public that the lake shouldn’t remain hazardous for long. The estimated wastewater discharge of around 4,000 cubic meters is minor compared to the lake’s total volume of 19 million cubic meters, allowing for rapid dilution.

Samples taken from local beaches last week showed that the microbiological quality of the water met swimming standards, but precautionary measures will continue with new samples being collected this Thursday. Testing specifically looked for E. coli and enterococci.

Meanwhile, the Vantaa River and Helsinki Region Water Protection Association reported the presence of fecal bacteria in their samples collected last week, predominantly at the northern testing point in Järvenpää, although oxygen levels were satisfactory.

Kari Korhonen, CEO of the Central Uusimaa Water Protection Association, noted the need to reconsider the location of the pump station’s overflow pipe near swimming areas, as lessons should be learned from such events. The root cause of the overflow has been identified as a broken valve, with heavy rainfall on the incident day exacerbating the situation, highlighting the ongoing challenges posed by climate change on water management.