The herbicides 2,4-D and 2,4,5-T remain suspected by the Australian public of causing birth defects despite being cleared by two government inquiries. The inquiries were set up after what seemed to be an abnormally high number of babies born with deformities at Cairns in Northern Queensland and at Yarram some 2000 km to the south in Victoria. The herbicide 2,4,5-T is used extensively for spraying fields of sugar cane near Cairns, and use of both this herbicide and 2,4-D were suspected of causing the deformities at Yarram.
The federal National Health and Medical Research Council reported in June this year that it could find no substantial scientific evidence of a causal link between the use of 2,4,5-T and human birth defects. It also stated that “the use of 2,4-D is not producing any risk to human health.”
In its report, which was published late last month, the Victorian state government’s investigation into the birth defects at Yarram also failed to establish a statistical link between the use of 2,4,5-T and birth defects. However, no sooner had that report been published than a further group of birth deformities came to light at the Victorian town of Sale. In this case, four deformed babies were born at the same hospital between September and December last year. One had no brain, another spina bifida, the third underdeveloped internal organs, and the fourth a cleft palate. The mothers of all these babies lived in houses that faced a playing field that had been sprayed with a strong formulation of 2,4-D to control weeds. State premier Dick Hamer announced last week that another inquiry will be held into these birth defects at Sale.
According to the National Health and Medical Research Council, Australia uses about 2000 tonnes of 2,4-D and 250-300 tonnes of 2,4,5-T each year. Implicating or clearing these herbicides of causing the birth defects will be particularly difficult. At both Yarram and Cairns the basic statistics needed to determine whether the respective clusters of birth defects truly constitued epidemics were apparently just not available. At Yarram birth deformities were found in about 8 per cent of births, while at Cairns the figure was 6 per cent.
Submission to NSW Government Enquiry into the Herbicide 2,4,5-T. From Council on Environmental Hazards PO Box 238 North Quay 4000 Qld. Prepared by Paul Rogers
p8-10…Relevant Data from Queensland
Data from a survey of birth abnormalities in the Cairns region in 1978 is presented plus date from Queensland’s Childhood Malignancy Register. Queensland does not have an adult cancer register.
In 1978 former director of Public Heath Dr. R.C. Rogers, conducted an investigation of a reported high incidence of birth abnormalities in the Cairns region. He surveyed two thousand births for twelve months prior to 1st June, 1978… The high figure is for neural tube abnormalities which were eleven out of two thousand. There were eleven perinatal deaths, cause undetermined. A percentage of these is likely to be for neural tube. The Queensland Health Department reported that no increase of significance was noted on the basis of a comparison with data from a Sydney study in 1976 by Field. It was reported that the rate of 5.5 per thousand in Cairns for neural tube was not statistically higher than 2.81 in the Sydney study. This appears to be a deliberate attempt to distort the statistics. The Sydney figure of 2.81 per thousand refers to central nervous system defects, i.e. anencephaly and spina bifida (neural tube) and hydrocephalus, which is not classified as a N.T. abnormality. No cases of hydrocephalus were reported from Cairns. In fact, the Health Minister at the time, Dr. L. Edwards had been reported in the press as saying that hydrocephalus was not associated with 2,4,5-T/TCDD.
Abnormality Rate/1,000 Births Cairns Rate/1,000 Births Sydney
Neural Tube 5.5 1.71
Hydrocephalus Not Reported 1.09
Total C.N.S 5.5 2.81
The figures the Queensland Health Department should have used are 5.5 compared to 1.72. Also perinatal deaths were included in the Sydney figures but not in the Cairns figures. The statistical significance of the data has been confirmed by a statistician. The significance of this data is that neural tube abnormalities in the Cairns region in that period were three and possibly up to five times higher than what the national average can reasonably be estimated to be.
2,4,5-T is used heavily in the cane growing regions of North Queensland and is aerially sprayed. I should emphasize that the data above does not represent a statistically significant relationship with 2,4,5-T use. It does however, I believe, indicate a statistically significant excess of neural tube abnormalities over the national average. As 2,4,5-T/TCDD is an established animal teratogen every effort should be made to design studies to elucidate the relationship between the herbicide, or other teratogens, and birth abnormalities in the region. This is not being done to our knowledge.
Childhood Malignancy Register
The Register has presented two annual reports – 1979 and 1980. Although the Register is in its infancy, some trends have been detected.
An unusually high incidence of medulloblastoma, a brain tumour, retinoblastoma, an eye tumour, and Hodgkins disease have been detected in North Queensland and other crop growing areas that utilize phenoxy herbicides heavily, such as the Darling Downs.
The Chairman of the Register, Dr W.R. McWhirter recently told the House of Representatives Standing Committee on Environment and Conservation that “we strongly suspect that there is some form of environmental agent which is capable of inducing medulloblastoma. This tumour seems to have a tendency to a higher incidence in children born in rural areas”. This was included in a submission to the committee’s enquiry into hazardous chemicals.
The high incidence of Hodgkins Disease in North Queensland may be significant. TCDD is a well established suppressor of cellular immune response in experimental animals due to thymus involution…