Semivolatile Organic Compounds in Water, Suspended Particulate Matter, Sediments and Biota in the Danube

During the second joint Danube survey (JDS 2) in autumn 2007, water, sediment, suspended particulate matter and mussel samples were collected from 23 sites covering the River Danube and important tributaries from Germany until the Black Sea. The compound classes investigated were polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs) and polyaromatic hydrocarbons (PAHs). The results revealed no exceeding of the environmental quality standards (EQS) according to the Directive 2008/105/EC for all investigated compounds except the ∑benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene, where the concentrations at most sites were close to the EQS of 2 ng/L. In five sites the EQS were slightly exceeded, with a maximum concentration 3.1 ng/L close to Bratislava. OCP concentrations in water were orders of magnitude below the EQS except for HCH that reached levels up to 25% of the EQS in the lower Danube. Maximum PBDE concentration in water was at 20% of the EQS. The longitudinal concentration profiles in water and sediment suggest DDT, HCH and to a lower extent chlordane and heptachlor releases into the lower Danube originating from left bank sources and tributaries especially Arges, Siret and Prut. PBDEs showed a maximum in the middle Danube stretch impacted from releases from the right bank tributaries such as Drava, Sava and Velika Morava. Concentrations in the investigated compartments were generally at the lower end of the concentration ranges typically found in European freshwaters.