Source: Conservation of Australian Amphibian and Reptile Communities by P.A. Rawlinson Proceedings of the Melbourne Herpetological Symposium Zoological Board of Victoria; July 1981.
In the early 1960s extensive areas around Heytesbury were cleared of natural vegetation and sown with introduced grasses for conversion to dairy pasture. Insect pests, especially underground grass caterpillars and Oxycanus grubs, invaded the pastures and by early 1963 were causing considerable damage. A ready solution seemed at hand, however, for in autumn 1962 the Victorian Agricultural Department had experimented with a new persistent organo-chlorine pesticide 'Telodrin' (isobenzan) in the Yanakie district of Gippsland and successfully controlled outbreaks of underground caterpillars in pasture. Even better, Telodrin proved so persistent at Yanakie that in treated areas no new infestations were reported and additional spraying was not necessary. Unfortunately for the Heytesbury area, the Agriculture Department's experiments did not extend to the pesticide's effects on non-target species or the environment. After the successful Yanakie experiments Telodrin was registered for use in Victoria on pastures to control underground pests.
In February 1963 pastures on a large number of farms in the Heytesbury areas were treated with Telodrin to control heavy infestations of underground grass caterpillars and Oxycanus grubs. Pastures in the area not sprayed in February were sprayed in late March and early April. It soon became apparent that the human ecosystem had become contaminated as a few weeks after spraying nervous symptoms developed in dairy cattle feeding from the pastures and a number of calves died. Rabbits feeding from the pastures died in numbers and deaths occurred amont dogs and cats in the area, apparently after eating Telodrin-poisoned rabbits. Finally nervous symptoms appeared in adults and babies after consumption of local milk, and the Departments of Agriculture and Health launched an investigation into the human health aspects. Substantial contamination of animal tissues with Telodrin was confirmed by electron capture gas chromatography on 28th May and extensive sampling revealed wide-spread contamination of pastures, animals and farm produce. As reports of nervous symptoms continued to surface in June, all milk from the area was withheld from sale for human use in July. The contaminated milk was sold for use in caesin and soap manufacture.
From July 1963 onwards 90 Heytesbury farms were monitored at fortnightly or monthly intervals for Telodrin levels in milk. As soon as they fell below an arbitary level of 0.02 parts per million, the milk was allowed to re-enter the market for human consumption, and the farm was declared free. On this basis all farms were declared free by April 1964 and regular monitoring for Telodrin was restricted to milk..."
Source: Conservation of Australian Amphibian and Reptile Communities by P.A. Rawlinson Proceedings of the Melbourne Herpetological Symposium Zoological Board of Victoria; July 1981.
“… For example, Littlejohn, Watson and Loftus-Hills (1971) reported a previously unsuspected zone of contact hybridization between Geocrinia Laevis and G. Victoriana in the Heytesbury area of south-western Victoria. Unknown to the authors (and to the Victorian public at large), this area was involved in an extensive, but little publicized, ‘pesticide incident’ in 1963. Although the ‘incident’ was not well documented publicly, a brief account was published in the ‘Report of the Committee of Enquiry into the Effects of Pesticides in Victoria’ (1966) and additional information was provided by Belcher (1980).
In the early 1960s extensive areas around Heytesbury were cleared of natural vegetation and sown with introduced grasses for conversion to dairy pasture. Insect pests, especially underground grass caterpillars and Oxycanus grubs, invaded the pastures and by early 1963 were causing considerable damage. A ready solution seemed at hand, however, for in autumn 1962 the Victorian Agricultural Department had experimented with a new persistent organo-chlorine pesticide ‘Telodrin’ (isobenzan) in the Yanakie district of Gippsland and successfully controlled outbreaks of underground caterpillars in pasture. Even better, Telodrin proved so persistent at Yanakie that in treated areas no new infestations were reported and additional spraying was not necessary. Unfortunately for the Heytesbury area, the Agriculture Department’s experiments did not extend to the pesticide’s effects on non-target species or the environment. After the successful Yanakie experiments Telodrin was registered for use in Victoria on pastures to control underground pests. This is puzzling as Telodrin, a close relative of Dieldrin, Endrin and Aldrin, was not registered for use in most countries after it proved to be highly persistent and up to ten times more toxic than Dieldrin in experimental animals (Jager, 1970). In fact Dieldrin and Aldrin were under fire by 1962 because of their high toxicity and persistence, and in the United States their registrations for most uses were cancelled in 1971 (Caswell, 1980).
In February 1963 pastures on a large number of farms in the Heytesbury areas were treated with Telodrin to control heavy infestations of underground grass caterpillars and Oxycanus grubs. Pastures in the area not sprayed in February were sprayed in late March and early April. It soon became apparent that the human ecosystem had become contaminated as a few weeks after spraying nervous symptoms developed in dairy cattle feeding from the pastures and a number of calves died. Rabbits feeding from the pastures died in numbers and deaths occurred amont dogs and cats in the area, apparently after eating Telodrin-poisoned rabbits. Finally nervous symptoms appeared in adults and babies after consumption of local milk, and the Departments of Agriculture and Health launched an investigation into the human health aspects. Substantial contamination of animal tissues with Telodrin was confirmed by electron capture gas chromatography on 28th May and extensive sampling revealed wide-spread contamination of pastures, animals and farm produce. As reports of nervous symptoms continued to surface in June, all milk from the area was withheld from sale for human use in July. The contaminated milk was sold for use in caesin and soap manufacture.
From July 1963 onwards 90 Heytesbury farms were monitored at fortnightly or monthly intervals for Telodrin levels in milk. As soon as they fell below an arbitary level of 0.02 parts per million, the milk was allowed to re-enter the market for human consumption, and the farm was declared free. On this basis all farms were declared free by April 1964 and regular monitoring for Telodrin was restricted to milk; no monitoring was carried out on animal fat or meat in spite of the fact that carcasses were sold for human consumption. More importantly no continual monitoring of soil was carried out and it is probable that substantial amounts persisted in the soil for at least a decade. Tragically the effects on wildlife were not documented in spite of the fact that many species were known to have been killed including magpies, quail and ravens…”