Tervajoki River in Janakkala reveals long-lasting PCB contamination despite decades of cleanup efforts

The Tervajoki River in Janakkala exemplifies the prolonged recovery process of previously polluted water bodies. Despite the cessation of PCB use 40 years ago, harmful PCB compounds are still present in the river’s sediments. Experts previously acknowledged the lasting nature of these pollutants, but they were nonetheless surprised by the high concentrations measured in the river.

PCBs entered Tervajoki and Kernaalanjärvi via wastewater from a paper mill operated by the Tervakoski company, where PCBs were used in quality assurance tests from 1956 to 1984, long before their harmful effects were understood. The Finnish central bank owned the factory at that time. Starting in 1970, PCB waste oils were collected for disposal elsewhere. The manufacture and sale of PCB compounds were banned in Finland in 1990.

PCBs are harmful to both health and the environment, classified alongside other notorious pollutants like DDT and dioxins. They have been utilized in industrial chemicals, capacitors, transformers, and hydraulic oils, and can be released into the environment through waste incineration and industrial processes. Particularly toxic to aquatic life, PCBs are known to cause reproductive and developmental disorders and have been linked to cancer from high levels of occupational exposure.

Sanni Manninen Johansen from the Häme ELY Centre points out that Finland has other similar sites with a long industrial history, such as the Kymijoki River, which was considered for restoration but ultimately abandoned due to insufficient cleaning capacity.

Recent tests on Tervajoki sediments revealed PCB contamination at four sampling sites, with three showing elevated concentrations. Manninen Johansen noted that while over three billion cubic meters of water have flowed through the river since pollution ceased, sediment disturbance could resuspend PCBs and potentially increase fish contamination. Consequently, the sediment is best left undisturbed, while current fish consumption restrictions remain unchanged.