Persistent organic pollutants are subject to long-range transport and also occur in the environment far from their source. They accumulate in the suspended solids of watercourses and in the food chain. They are toxic to humans and wildlife.
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The Stockholm Convention aims to eliminate or restrict the worldwide production, use and release of persistent organic pollutants (POPs). The Convention was transposed to applicable EU legislation (Regulation (EC) No 850/2004) and entails extensive reporting requirements for the Member States. The German Ordinance on Surface Waters also regulates 14 of the POPs.
The Ordinance on Surface Waters defines environmental quality standards (EQS) for the concentrations of suspended solids/sediment (polychlorinated biphenyls (PCB)), in biota and total water (brominated diphenyl ethers (BDE), heptachlor, hexabromocyclododecane (HBCDD), hexachlorobenzene (HCB), hexachlorobutadiene and perfluorooctanesulfonic acid (PFOS)). The biota EQS for heptachlor, HBCDD and PFOS were converted into annual average EQS for total water. However, assessment must occur based mainly on measurements in biota, and for PCBs, on measurements in the suspended solids/sediment. The aim of the biota EQS for the very bioaccumulative BDE, dioxins, heptachlor, HCB and PFOS is to protect human health when consuming fishery products. For HBCDD and hexachlorobutadiene the aim of the applicable biota EQS is to protect wildlife which feed on fish or mussels.
For the 2014-2016 period, there was compliance with environmental quality standards for the cyclodiene pesticides, endosulfan, pentachlorobenzene, pentachlorophenol and total DDT (including 4,4-DDT).
Exceedances for total hexachlorocyclohexanes (HCH), dioxins, PCB28, PCB52, PCB101, PCB138, PCB153, PCB180 and HCB were detected at one and up to seven measuring sites. The biota EQS for total BDE was exceeded at all measuring sites as was heptachlor/heptachlor epoxide at 85% of sites where measured levels were higher than the limit of quantification. The biota EQS for PFOS was exceeded at about one third of all measuring sites.
Bans or limits on the production, use and release of several of these 14 POPs have been in effect in Germany since the 1980s. Their concentrations in the environment remain very high on account of their persistence. Floods and dredging activities in or on the banks of water bodies can potentially remobilise contaminated sediments. For example, HCH and HCB have been detected in varying concentrations in suspended solids in the Elbe and Mulde rivers.
An earlier use of POPs, for examples in coatings, seals (PCB) or insulation materials (HCBDD) can be the source of their continued release into the environment. Such a case occurred during the renovation of a railway bridge in the Czech Republic, once again increasing the concentrations of PCB in suspended solids in the Elbe river. Germany's National Implementation Plan under the Stockholm Convention on Persistent Organic Pollutants contains an overview of the POPs sources and measures to reduce their release.
PFOS are in the group of per- and polyfluorinated chemicals (PFC) and were used for many years in certain fire-fighting foams and in electroplating. The regulations in the Stockholm Convention require that other substances in this group be used to replace PFOS. The German Environment Agency is working in many areas to achieve a reduction of PFC releases into the environment and to regulate this group of substances (PFC risk management measures).
The impact of climate change will be felt more strongly in the future – and in Germany too. This is the conclusion reached in what is called the vulnerability analysis, a comprehensive study on Germany's vulnerability to climate change.