Identifying the research needs in the global assessment of toxic compounds 10 years after the signature of the Stockholm Convention

Persistent organic pollutants (POPs) are targeted by the Stockholm Convention for reduction and eventual elimination from production, trade and release. All POPs share properties that make them long lived (persistent), get enriched along the food chains (bioaccumulative), present at elevated concentrations in remote locations (prone to long-range transport) and elicit adverse effects (toxic). Since its adoption on 22 May 2001, the convention has identified just over 20 chemicals and groups of compounds as POPs. These include the original ‘dirty dozen’ compounds as the coming into force of the convention (aldrin, chlordane, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, toxaphene, DDT, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls), followed by another nine compounds in 2009 (chlordecone; hexabromobiphenyl; tetra-, penta-, hexa- and hepta bromodiphenylether; α-hexachlorocyclohexane; β-HCH; γ-HCH (lindane); pentachlorobenzene; perfluorooctane sulfonic acid, its salts and perfluorooctane sulfonyl fluoride). In 2011, endosulfan was added to the list.

Ten years later, after the adoption of the convention, an expert meeting was organized by the Regional Centre of the Stockholm Convention for capacity building and transfer of technology in Central and Eastern Europe, the Research Centre for Toxic Compounds in the Environment of Masaryk University, and held in Brno, Czech Republic, on May 22–24, 2011, with the support of the Secretariat of the Stockholm Convention (SSC), the Ministry of the Environment of the Czech Republic, the European Association for Chemical and Molecular Sciences—Division of Chemistry and the Environment and the American Chemical Society. The topics addressed were on aims and instruments of the convention and cooperation with related conventions (Rotterdam, Basel) and protocols, national policies and stakeholders, in particular science.

The workshop participants assessed progress with the Stockholm Convention and identified major knowledge gaps, challenges and research needs associated with the global assessment of hazardous chemicals. The expertise of 40 invited scientists from 16 countries of three UN regions was sought and supplemented by experience of the representatives of the SSC, UNEP, and government. Their expertise encompasses the fields of environmental chemistry and exposure modelling; monitoring of air, water and biota including human exposure, effects and risks; and data interpretation and management. The participants identified 10 major priority areas for future work (Klanova et al. 2011):

• 1. Source control of POPs and other chemicals

• 2. Global scale transport, sources and sinks

• 3. Persistence of chemical compounds

• 4. Tools for monitoring of chemical concentrations and fluxes

• 5. Future trends and scenarios

• 6. Global monitoring plan

• 7. Global Earth Observation System of Systems (GEOSS)

• 8. Capacity building

• 9. Limiting adverse effects from hazardous chemicals

• 10. Effective science to serve policy needs

This special issue of ESPR compiles contributions from workshop participants that highlight the current scientific knowledge of POPs and the implementation of the SC, knowledge gaps and future research directions.

In more detail, the contributions of Dvorská et al., Aliyeva et al., Adu-Kumi et al., Cecinato et al. and Mosca et al. report on case studies addressing various classes of legacy POPs and/or emerging contaminants in polluted environments of Armenia, Azerbaijan, Ghana and Italy (two papers), respectively. The paper by Mikeš et al. reports on long-term monitoring of POPs in breast milk from the Czech Republic. The papers by Vicaretti et al. and Wong et al. focus on key processes of POP cycling, i.e. emissions (of PCDD/Fs from waste incineration) and air–sea exchange (of α-HCH), respectively. Stemmler and Lammel study long-term cycling of PCB on the regional scale with a multicompartment chemistry-transport model. The contributions of Balducci et al. are a review of analytical techniques for the quantification of a wide spectrum of POPs and emerging contaminants in atmospheric matrices, and the paper of Lohmann et al. is a review on the state of the art with regard to passive sampling techniques in aqueous matrices.