Sources of dioxin

Press, 10 November 1986, Page 20

Sources of dioxin

The community can feel rather more confidence about the manufacture and use of the herbicide 2,4,5-T after the report of a Ministerial Committee of Inquiry last week. The report confirms an earlier study by the Environmental Council which found little evidence of a serious public health risk from the herbicide in New Zealand. However, the Minister of Health, Dr Bassett, has said that workers at the New Plymouth plant where the weedkiller is made may be at risk. Manufacture will continue, as will further investigations.

Continued production of 2,4,5-T is good news for primary producers and for New Zealand’s agricultural industries. The matter should not be permitted to rest, however. The latest recommendations, including that for further study of the manufacture of the weedkiller need to be heeded. The chemical has been enormously valuable to New Zealand, but there should be continuing confidence that any risk to health is very low, and is being further reduced. The startling ingredient in the latest report is the committee’s finding about the effects of lead in petrol. Burning leaded petrol in motor vehicles may add much more of the poison dioxin to the New Zealand environment than does the use of 2,4,5-T. The

inquiry has had access to a Swedish report not yet made public. Further research, in New Zealand, is urgently needed to determine whether leaded petrol here poses the health risk that research in Europe has suggested. The Government has a policy to introduce unleaded petrol slowly into New Zealand from early next year. The change had been expected to take a decade. Now it may have to be made much more quickly. The problem is that most vehicles on New Zealand roads would not run properly, without modification, if they were used with unleaded petrol. Many might not keep running at all. Modification of engines would be expensive. The alternative, further modification of New Zealand’s petrol, could also be expensive. These are unhappy possibilities. On the evidence that has emerged so far, the old villain, 2,4,5-T is rather less of a hazard than some people have insisted. A new villain — lead in petrol — may be a much more serious risk to public health. A start must be made now to determine the extent of the risk, and how it might best be overcome without rendering obsolete most of the country’s motor vehicles, or the refinery that produces the fuel they run on.