An analysis of catchment factors associated with heavy metal export into the Baltic Sea and Nature-Based Solutions aimed at its limitation (dataset)

Abstract

The aim of the study was to determine the contribution of individual Baltic countries to the inflow of metal loads into the Baltic Sea and to identify patterns of similarity between these countries in terms of the causes of heavy metal loads. HELCOM and EUROSTAT data were used in the analyses. The results indicate that Finland and Sweden generate the highest total loads of heavy metals flowing through rivers. However, Lithuania and Finland stand out for their high metal loads per km² of catchment area. Clustering the countries based on their similarity in heavy metal loads delivered to the Baltic Sea led to the identification of three groups. Finland and Lithuania generate the highest average loads of cadmium, chromium, nickel, and zinc per unit area [kg/km²/year]. Estonia and Latvia generate the highest average annual loads of lead, mercury, and copper. Poland, Germany, and Sweden generate the lowest heavy metal loads. The collected data were also used to analyze correlations between aquaculture production in the Baltic Sea basin, the number of cattle, beef, sheep, pigs, poultry, and the meat produced from them, the amount of waste and trucks, grain production, fertilizers use, and heavy metal loads reaching the Baltic Sea via rivers. The results obtained from these analyses indicate the need for continuous monitoring of heavy metal loads and transfers to the Baltic Sea, as well as for actions aimed at eliminating them from the environment, such as Nature-Based Solutions, which are affordable and environmentally friendly methods for removing pollutants from surface waters.