Trace metals and organic compounds in sediment samples from the River Danube in Russe and Lake Srebarna (Bulgaria)

 In 1995 the contamination status of accumulated fine surface sediments and effluent material from the River Danube in Russe (Bulgaria) was analysed for trace metals (Hg, Cd, Pb, Cu, Zn, Cr, Ni, As), polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), hexachlorobenzene (HCB), 1,1,1-trichloro-2,2-bis [chlorophenyl] ethane (DDT), 1,1-dichloro-2,2-bis [chlorophenyl] ethylene (DDE), 1,1-dichloro-2,2-bis [chlorophenyl] ethane (DDD), and hexachlorocyclohexanes (α-, β-, γ- and δ-HCH) to achieve basic information about the River Danube in Bulgaria. The range of trace-metal levels came close to or below the intended quality criteria for the River Elbe in Germany. The only exceptions were Pb in a shipyard, exceeding the final criteria by a factor of 17, and Cr downflow from a metal factory. In one sample from a shipyard (D8) the highest trace metal concentrations were analysed in the fraction 125–2000 μm. The maximum measured PAH contents exhibited a contamination on the lower μg g^–1 d.w.-level (dry weight base), traces of PCBs, HCB and DDD/DDE were analysed in the ng g^–1 d.w.-range. DDT and HCHs were not detected in any sample. The trace-metal and organic-compounds level in sediments from Lake Srebarna (UNESCO-Biosphere Reserve) displayed completely background character. Received: 18 March 1997 · Accepted: 21 July 1998