The Stockholm Convention requires Parties to take measures to reduce or eliminate releases of persistent organic pollutants (POPs) from intentional production and use, from unintentional production and from stockpiles and wastes. The chemicals intentionally produced and currently assigned for elimination under the Stockholm Convention are the pesticides aldrin, chlordane, dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex and toxaphene, as well as the industrial chemical Polychlorinated Biphenyls (PCBs).
The Convention also seeks the continuing minimisation and, where feasible, elimination of the releases of unintentionally produced POPs such as the by-products from wet chemical and thermal processes, polychlorinated dibenzo-p-dioxins/-furans (PCDD/Fs) as well as HCB and PCBs. Concepts of Best Available Techniques and Best Environmental Practices to achieve such minimisation and reduction from all potential source categories will be further developed by the Conference of the Parties. Cement kilns co-processing hazardous waste are explicitly mentioned in the Stockholm Convention as an industrial source having the potential for comparatively high formation and release of these chemicals to the environment.
The cement industry takes any potential emission of POPs seriously, both because perceptions about these emissions have an impact on the industry's reputation, and because even small quantities of dioxin-like compounds can accumulate in the biosphere, with potentially long-term consequences.
The objective of this study was to compile data on the status of POPs emissions from the cement industry, to share state of the art knowledge about PCDD/F formation mechanisms in cement production processes and to show how it's possible to control and minimise PCDD/F emissions from cement kilns utilising integrated process optimisation, so called primary measures.
In 2005, the CSI released the final version of this report on POPs emissions in the cement industry. The report was based on in depth scientific studies conducted with help from The Foundation for Scientific and Industrial Research (SINTEF) of Norway, a response to concerns from stakeholders regarding hazardous emissions from co-processing of waste materials in cement kilns. These studies concluded that emissions of organic compounds like dioxins and furans from well-operated dry cement kilns were of less than one part per billion in the air, and also ascertained that co-processing of waste in cement kilns did not lead to increased emissions of hazardous organic compounds. These findings have been backed up by similar studies done by the United States Environmental Protection Agency (EPA), and the United Kingdom's Environmental Agency.
The CSI has comprehensively reviewed POPs emissions from cement plants, and worked closely with the Stockholm Convention (on POPs) Secretariat to help formulate reliable control measures as required under the convention.