Links between pollutants and cancers highlighted again
The links between environmental pollutants and the growth of cancers has been highlighted again in two separate studies.One of these showed a high correlation between atmospheric pollutants and childhood cancer, while another highlights a link between pesticides, particularly weedkillers, and prostate cancer.
George Knox, emeritus professor of epidemiology at the University of Birmingham, compared maps of atmospheric chemical emissions for the UK with details of children under 16 who had died from leukaemia and other cancers.
He found that there was a significantly increased risk of contracting childhood cancers and leukaemias within one kilometre of "hotspots" of industrial emissions such as carbon monoxide, PM10 particles, volatile organic compounds, nitrogen oxides, benzene, dioxins, 1,3-butadiene, and benz(a)pyrene.
The study states that: "Calculated attributable risks showed that most childhood cancers and leukeamias are probably initiated by such exposures."
It adds that, of the pollutants listed above: "The mother probably inhales these or related materials and passes them to the foetus across the placenta."
The study, published in the Journal of Epidemiology and Community Health, cites transport fumes, industrial combustion processes and oil and /or gas burning as the main cause of these pollutants. Professor Knox found that sulphur dioxide emissions, which arise mainly from coal burning, failed to mirror the patterns found with the other pollutants, suggesting that coal burning was not a major factor.
Dr Lesley Walker, Director of Cancer Information at Cancer Research UK, played down the results of the study: "The evidence that most childhood cancers are "probably down" to industrial and environmental pollutants is very thin. A wealth of information suggests that leukemia, the most common type of cancer in children, may be a rare response to an unidentified but common infection. This is a complex area to research - not least because cancers in children are rare and some may have an underlying genetic basis."
Meanwhile, the Department of Health's advisory committee has called for greater monitoring of the occupational exposure of farmers and farmworkers to agricultural chemicals. The committee had been reviewing reasons for a large increase in prostate cancer over the past 20 years and concluded that agricultural labour was the only job-related link.
The committee said this link should be kept under review and said there was a need for improved measures of exposure to pesticides, particularly herbicides.
Friends of the Earth and other environmental groups who have been campaigning on this issue were heartened by the statement, but Cancer Research UK still remained cautious: "The causes of prostate cancer are not clear-cut. However, two that are known to be important are age and family history," Dr Emma Knight told edie.
She pointed out that the investigation concluded that recent increases in prostate cancer incidence are largely due to new techniques improving diagnosis but did posit a possible link between farmers, exposure to pesticides and increased risk of prostate cancer.
"Because of the sparsity of the information in this area, Cancer Research UK welcomes this Government-led review," she concluded.
By David Hopkins