Finland updates strategy for managing acid sulfate soil challenges along coastal regions

Acid sulfate soils pose a significant environmental challenge, particularly along Finland’s coast. These sulfur-rich sediment layers, formed thousands of years ago, have emerged as the land rises. They present corrosion risks to building foundations and other structures, as well as potential harm to water bodies and groundwater. The acidity can adversely affect aquatic life, especially if the water pH drops below 5.5.

In response to this pressing issue, Finland developed its first strategy for managing the impacts of acid sulfate soils in 2011. Although the results have been monitored, an evaluation in 2022 indicated that a new strategy is necessary, according to Eeva Nuotio, a leading water management expert from South Ostrobothnia. This update is particularly timely given the challenges posed by climate change, including prolonged dry periods followed by heavy rainfall, which can exacerbate soil acidity.

Land use has evolved over the years, further complicating the issue. The new strategy will also address challenges related to black schist, a type of geological formation that can create similar acid sulfate soil problems. The updated strategy is expected to be finalized by the end of the year.

Despite awareness of the issues related to acid sulfate soils, complete prevention is unattainable, Nuotio notes. Activities like land excavation and drainage expose sulfur-bearing materials to oxygen, leading to harmful soil reactions. Effective land management planning is crucial, particularly in areas with acid sulfate soils where specialized construction measures are required. It is essential to maintain groundwater levels appropriately through techniques like controlled drainage and irrigation to mitigate these risks.