Dioxin in the Elbe river basin: policy and science under the water framework directive 2000–2015 and toward 2021

Abstract

A critical review of the last 25 years of dioxin policy in the Elbe river catchment is presented along seven main theses of the River Basin Community (RBC)-Elbe background document “Pollutants” for the Management Plan 2016–2021. In this period, polychlorinated dibenzodioxins/-furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) will play a major role: (i) as new priority substances for which environmental quality standards (EQSs) need to be derived (Directive 2013/39/EC); (ii) in the search for innovative solutions in sediment remediation (i.e., respecting the influence of mechanical processes; Flood Risk Directive 2007/60/EC); and (iii) as indicators at the land–sea interface (Marine Strategy Framework Directive 2008/56/EC). In the Elbe river catchment, aspects of policy and science are closely connected, which became particularly obvious in a classic example of dioxin hot spot contamination, the case of the Spittelwasser creek. Here, the “source-first principle” of the first cycle of the European Water Framework Directive (WFD) had to be confirmed in a controversy on the dioxin hot spots with Saxony-Anhalt’s Agency for Contaminated Sites (LAF). At the Spittelwasser site, the move from “inside the creek” to “along the river banks” goes parallel to a general paradigm shift in retrospective risk assessment frameworks and remediation techniques for organic chemicals (Ortega-Calvo et al. 2015). With respect to dioxin, large-scale stabilization applying activated carbon additions is particularly promising. Another important aspect is the assessment of the ecotoxicology of dioxins and dl- PCBs in context of sediment mobility and flood risk assessment, which has been studied in the project framework FloodSearch. Currently, the quality goals of the WFD to reach a “good chemical status” are not met in many catchment areas because substances such as mercury do and others probably will (PCDD/Fs and dl-PCB) exceed biota-EQS values catchment area-wide. So far, relating biota-EQS values to sediment-EQSs is not possible. To overcome these limitations, the DioRAMA project was initiated, which has led to improved approaches for the assessment of dioxin-contaminated sediment using in vitro bioassays and to a robust dataset on the interrelation between dioxins and dioxin-like compounds in sediments and biota.Electronic supplementary materialThe online version of this article (doi:10.1186/s12302-016-0075-8) contains supplementary material, which is available to authorized users.

Reviewing the relevance of dioxin and PCB sources for food from animal origin and the need for their inventory, control and management

“…This is six–ten times above background dl-PCB levels of German pasture land soil [ 63 ], and is sufficiently high to explain the contamination levels in the eggs (see above). River floodplains: in the past, PCBs and other POPs have been deliberately released into rivers as a means of “waste management”, leading to sediment contamination [ 102 , 103 , 116 , 117 ]. During flooding events, contaminated sediments are translocated to river floodplains [ 118 , 119 ].…”

“…These legacies are now stored in soil, sediments and other reservoirs, such as landfills and contaminated sites [ 8 , 116 , 132 ]. The PCDD/F (and PCB) pollution is ubiquitous in soil and sediments.…”

“…For example, the historical emission inventory of a single Norwegian magnesium production plant was estimated at 50 to over 100 kg TEQ [ 182 ]. For the German magnesium/titanium productions in Bitterfeld, Staßfurt and Aken, high historical emissions have been documented, which have led to contamination of the Mulde, Bode, Saale and Elbe river basins, the Port of Hamburg, and a corridor in the North Sea [ 116 , 183 – 185 ]. Alluvial soil on flood plains along 400 km of the Elbe river has been contaminated with high levels of PCDD/Fs.…”

An assessment of the concentrations of PCDDs/Fs in contaminated bottom sediments and their sources and ecological risk

“…Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) are both examples of persistent organic pollutants (POPs) (Lee et al 2006;Li et al 2012;Lewandowski et al 2014;Förstner et al 2016;Louchouarn et al 2018). The persistence and hydrophobicity of PCDDs/Fs and their resistance to degradation make them a significant ecotoxicological problem, one that is difficult to control (Nieuwoudt et al 2009;Roumak et al 2018).…”

“…PCDDs/Fs demonstrate good stability in a water environment; this has been attributed to their low solubility and thus strong adsorption on organic matter particles and lipids, which results in up to 97% of emitted PCDDs/Fs being deposited in sediments. Moreover, due to their high octanol-water partition confections (log K ow 4-8), PCDDs/Fs undergo bioaccumulation in sediment-dwelling organisms and biomagnification in both aquatic and terrestrial food chains (Lee et al 2006;Micheletti et al 2007;Nunes et al 2011;Nie et al 2013;Urbaniak et al 2014;Förstner et al 2016;Roumak et al 2018). Consequently, the determination of PCDD/F concentrations in bottom sediments plays an important part in determining their ecological risk and human exposure (Micheletti et al 2007;Li et al 2012).…”