About 800 truckloads of contaminated soil removed from the Pajuluoma channel in Finland
A large-scale cleanup and reconstruction of about one kilometre of the Pajuluoma channel is nearing completion in the Finnish city of Seinäjoki. Approximately 800 truckloads of soil were removed from the contaminated section, while part of the new channel was built alongside the old one.
As YLE News reports, the project is expected to be completed about a year ahead of schedule. Much of the earthworks was carried out in winter, when water levels were low. Mikko Heiskanen, project manager at the Finnish Transport Infrastructure Agency, noted that the work was unusually challenging, and that technical solutions and quality requirements were partly developed during the permitting procedure and implementation process.
Contaminated sediments
Contamination of the Pajuluoma bottom sediments was discovered in the early 2000s. The problematic section, about one kilometre long, is located in the Pohja area between the VR railway premises and Highway 19.
Polycyclic aromatic hydrocarbons, oils, fuel, solvents and metals were found in the sediments. According to the source, these substances likely accumulated over decades and may be linked to the VR railway premises. At the same time, the exact source of the contamination has not been established, as urban stormwater runoff also enters the watercourse.
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Water quality control
During the cleanup, one of the main tasks was to prevent toxic sediments from spreading in the water. Pajuluoma flows through the straightened Seinäjoki channel into the Kyrönjoki River, from which Vaasan Vesi draws drinking water for Vaasa residents. Water quality at the intake, located about 70 kilometres from Pajuluoma, was monitored throughout the work period.
During certain cleanup stages, water was diverted around the water intake for safety reasons. Target levels were exceeded while contaminated sediment was removed from the old channel. In such cases, work was temporarily halted until substance concentrations decreased.
About one-third of the one-kilometre section was cleaned, while a new channel was built along two-thirds of it. Two bridges were also constructed across it: a pedestrian and cycling bridge on Pultrantie Street has already opened, while another bridge in the Ainonsola area is due to open in the coming weeks.
The project costs about €3 million. After the Finnish Transport Infrastructure Agency completes the work, water quality monitoring will continue for about another two years, and a final report is planned for November. In spring, the city of Seinäjoki will begin landscaping the area: a park, paths and meadow areas will be created, trees will be planted and benches installed. There are also plans to combat an invasive species, Himalayan balsam.
