The Greenpeace report was issued in April. It presented nine case studies to illustrate the range of organochlorine by-products formed during the manufacture of ethylene dichloride (EDC) and vinyl chloride monomer (VCM), both precursors of PVC (ENDS Report 219, pp 19-21 ). The report was part of a wider campaign by the group for a chlorine phase-out (ENDS Report 213, pp 15-18 ).
In its response, the ECVM accuses Greenpeace of selecting data to support preordained conclusions. Greenpeace, the ECVM claims, "has disqualified itself from holding the position of advocate for the environment...The truth is that the manufacture of PVC poses no threat to either human health or the environment".
The response draws attention to several errors in Greenpeace's report. One was a reference to a study by Dutch scientists which examined dioxin contamination in the Rhine delta and attempted to relate this back to specific sources. One segment of the Rhine was found to contain much higher levels of certain dioxins (PCDDs) and furans (PCDFs) than any other, and Greenpeace erroneously stated that this was the location of an Akzo VCM plant.
According to the author of that study, Dr Erik Evers, now at the Dutch Ministry of Transport and Water Management, the VCM plant in fact belonged to Dynamit Nobel, not Akzo. However, he told ENDS that he supports Greenpeace's interpretation of his study and subsequent work which analysed the PCDD/Fs formed during the laboratory-scale oxyhydrochlorination of ethylene to form EDC. The pattern of PCDD/F congeners formed from this process was "closely similar" to that found in the Rhine sediments.
Dr Evers has since carried out a similar analysis to determine the sources of PCDD/Fs in the surface sediments of several North Sea estuaries. The results are to be published shortly in the journal Environmental Toxicology and Chemistry. The preliminary findings of that study included high levels of PCDD/Fs in one sample from the Humber estuary (ENDS Report 195, p 9).
The full results indicate that in 13 out of the 15 samples taken from the Wadden Sea, the Dutch coastal oyster beds and the Ems-Dollard, Rhine, Wester Scheldt and Humber estuaries, PCDF concentrations were higher than those of PCDDs. Expressed in terms of the toxicity of the most toxic dioxin, 2,3,7,8-TCDD, total PCDD/F concentrations ranged from relatively low levels of 5-15ng/kg to 30-50ng/kg, but with the Humber estuary sample having a much higher value of 267ng/kg.
The dominant congener in the samples from the Rhine estuary, the Wadden Sea and the more offshore oyster beds was octachlorodibenzofuran (OCDF). The same congener fingerprint, with OCDF predominating, is found in effluent from two chlorination processes - oxyhydrochlorination to produce EDC, which is subsequently converted to VCM, and the electrolytic production of chlorine using graphite electrodes - a fairly out-dated technology.
The report of the study concludes that these processes "have a strong influence on the levels and profile of PCDDs and PCDFs in North Sea sediments. Such industries are located along the River Rhine in the Ruhr area, along some tributaries (River Lippe in Germany) and in the estuary (Chemieharbor in Rotterdam) of the Rhine."
Dr Evers says that his work confirms that the VCM and chlor-alkali industries along the Rhine are the primary source of PCDD/Fs in the sediments, rather than other candidates such as combustion and bleaching processes which give rise to distinctly different congener patterns.
He points out that while many European firms have installed treatment facilities in the last few years to reduce discharges of these compounds, there are still outstanding problems.
An example is Akzo's VCM plant in Rotterdam. In 1987, after this was found to have caused PCDD/F contamination of sediments in the local harbour, improved effluent treatment facilities were installed. The company says that this measure has reduced discharges to levels that make VCM production a negligible source of dioxins compared with other "everyday" sources. But the cost of removing the heavily contaminated sediment has been the subject of a long-running discussion between Akzo and the authorities.
The ECVM's response also accuses Greenpeace of building a case against VCM production by simply stating the quantities of by-products formed in the process, but not referring to the fact that most of these are subsequently treated or incinerated. The quantity of PCDD/Fs produced by modern EDC plants is also many times lower than Greenpeace calculated from the results of laboratory-scale experiments.
Greenpeace accepts that it erred in the case study which it attributed to Akzo, but maintains that its overall conclusions still stand.One of the report's authors, Geir Wang-Andersen, argues that "science is about putting the data together with any other factual information available, then asking questions and reaching conclusions...Our stated aim was to start a debate, not to produce the final word."
He accused the ECVM of trying to restrict the debate to the familiar issue of dioxins and ignoring the wider issues highlighted in the report - notably the wide range of organochlorines generated by VCM plants as well as problems such as leakages, fugitive releases, and the difficulties of final disposal of PVC products.
One of Greenpeace's objectives was to prompt regulatory authorities to ask more questions about PVC production before sanctioning further expansions of the industry. The group maintains that many environmental agencies were unaware of much of the evidence assembled in its report.
A key target was Norway's Environment Ministry, which had been considering for some time whether to approve an application by Norsk Hydro to build a 200,000 tonnes per year PVC unit on a fjord at Rafnes.
In August, the Ministry eventually sanctioned the project, on condition that Hydro reduces capacity at its existing PVC facility from 65,000 to 25,000 tonnes per year with 12 months. The fjord is understood to be heavily contaminated with organochlorines which have been released from a magnesium plant and Hydro's facilities.
In a report issued in August, Hydro says that the quantity of dioxins released from its VCM plant and a by-product incinerator on the same site are very small. For every 425,000 tonnes of VCM produced, the total amount of dioxins emitted to atmosphere is 0.025 grammes, while the discharge to the fjord is said to be 0.006 grammes.
Hydro describes the environmental constraints on the new plant as "the tightest yet imposed on the PVC industry anywhere in the world." The company says it was symbolically important for it to obtain the consent - but the o140 million plant may never be built due to uncertain market prospects for PVC. A decision on whether to proceed is expected within the next few months.
Meanwhile, on the other side of the Atlantic the chlorine industry is tackling the environmental challenge by facing up to the prospect of a complete phase-out of its business.
The Chlorine Institute, which represents 99% of US chlorine and related alkali production, recently published a report on the costs of replacing chlorine in 90% of its applications. The study was prompted by last year's recommendation by the International Joint Commission (IJC) on Great Lakes Water Quality - a joint US and Canadian government advisory group - that both countries should consider phasing out the use of chlorine and chlorine compounds as industrial feedstock.
The recommendation stemmed from the discovery of substantial organochlorine contamination in the Great Lakes. The Commission concluded that the only sure way to deal with the problem would be to "sunset" the industry that ultimately produces the chemicals.
The Institute's study was carried out by Boston-based Charles River Associates (CRA). It concludes that "using substitutes for chlorine-based products and processes would cost consumers an additional $91bn per year in the United States and $11bn in Canada.
"The investment needed to build plants to make the substitutes would approach $67bn. The transition would take 10 to 20 years and consumers would more than likely be forced to shoulder the cost over this period by paying higher prices for the products and services being eliminated." Around 45% of all US industries were found to be direct consumers of chlorine and its co-products, and all industries were found to be indirect consumers.
CRA concluded that "any policy decisions made on this issue that do not consider the consequences of a ban on chlorine production and use would be rash and would likely have a very damaging effect on the economic welfare of the USA and Canada."
Nevertheless, Greenpeace is jubilant about the CRA report. Campaigner Joe Thornton told ENDS that "in this study, the Chlorine Institute admits that there are alternatives available for essentially all uses of chlorine, details what they are, and says quite clearly that the transition to a chlorine-free world could be done in 10 to 20 years. Their only argument now is that it is too expensive."
Mr Thornton went on to ridicule CRA's cost estimates. In every case, he says, the study failed to take into account the economic benefits of phasing out chlorine that have already been demonstrated in practice, for example, by firms phasing out chlorinated solvents and in the pulp and paper industry. These include lower costs associated with cleaner production processes, lower chemical purchasing requirements, and lower disposal and liability costs.
Mr Thornton also focussed on CRA's estimate of the cost of substituting chlorine in pharmaceutical applications. This accounted for well over half of the total cost, although consumption by this sector accounts for only a small fraction of total chlorine use.
The CRA arrived at its figure by including the extra health care costs which would be incurred because people were assumed to suffer more ill-health. Greenpeace derides this assumption, saying that chlorine is often used in the manufacture of pharmaceutical products but only sometimes in the product itself, so that processes could be changed without necessarily losing products.
Moreover, Greenpeace says that its priority in calling for a chlorine phase-out is to eliminate bulk applications for which alternatives are already available - for example PVC, solvents and in pulp and paper bleaching - before tackling the fraction used in pharmaceuticals. Indeed, it concedes that for some pharmaceutical applications, alternatives to chlorine may not be available.
A second major report is due to be issued by the Chlorine Institute later this year. This will present the findings of an independent study into the toxicity of a range of chlorine-containing compounds.
Another important date on the chlorine industry's calendar this autumn will be a final report and recommendations on organochlorine use by the Great Lakes IJC's Virtual Elimination Task Force, which are due in October.