Elements and Persistent Organic Pollutants in the Sediments of the Sava River

Abstract

Among various stressors, aquatic ecosystems are exposed also to different inorganic and organic pollutants. The pollution of the Sava River is related mainly to the release of industrial wastes, untreated effluents from municipalities, and contaminants arising from agricultural activities. To assess the geographical distribution of sediment pollution, sediments were analysed at selected sites along the Sava River. Total element concentrations were determined and mobile element fractions and anthropogenic inputs of elements assessed. Selected persistent organic pollutants: polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), and chlorinated pesticides were also determined. In industrially exposed sites, Hg, Cr, and Ni were found in moderate concentrations (up to 0.6, 380 and 210, mg, kg−1, respectively). Since Cr and Ni exist in sparingly soluble forms, they do not represent an environmental burden. Elevated P concentrations up to 1,000, mg, kg−1 were found at agricultural areas and big cities. Regarding elements, the environmental status of sediments of the Sava River is comparable to other moderately polluted rivers in Europe, if rivers impacted by mining are not considered. Among the organic pollutants PAH were present in moderate concentrations (sum of 16 PAH up to 2,000, ng, g−1 with two exceptions with elevated PAH concentrations up to 4,000, ng, g−1 located downstream the oil fields) and their concentrations increased downstream the river. Concentrations of PCB were low (the sum of 7 indicator PCB was below 4, ng, g−1). Among selected pesticides, p,p′-DDT were found in moderate concentrations in sediments at two sampling sites in Croatia (up to 3, ng, g−1) and HCB in high concentration in the city of Belgrade (91, ng, g−1), although the use of these persistent pesticides has been banned for many years. Considering the organic pollutants, Sava is a moderately polluted river. The results of this study contribute to knowledge on the extent of pollution of sediments of European rivers and are important for water management institutes and local authorities, which may use these data for sustainable use, management, and protection of the Sava River water resources.