Pollution exposure linked to childhood cancer

Childhood cancers are strongly linked to engine exhausts from cars and factories, it was claimed yesterday.

Scientists made the link by linking pollution "hotspots" on a map of Britain to a higher risk of childhood cancer.

Exposure soon after birth, or even before, to combustion gases and particularly engine exhaust, is strongly linked to the development of childhood cancers like Leukemia, according to a report from the UK.

"These results confirm the relative proximities of child cancer births to substance-specific hotspots from oil-based emissions, and to industrial sites known to discharge such materials," Dr. E. G. Knox, from the University of Birmingham, reports in the Journal of Epidemiology and Community Health.

In the study, Dr. Knox linked emission hotspots for specific chemicals, from maps available on the Internet maps, to the birth addresses of children who later died from leukemia or other cancers before their 16th birthday.

An excess risk of childhood cancer was noted in hotspots for a variety of chemicals, including carbon monoxide, nitrogen oxides and 1,3-butadiene.

Although many of the associations seemed to be artifactual, an independent link with 1,3-butadiene and carbon monoxide remained.

Knox notes that these chemicals, which are largely produced by engine exhausts, were powerful predictors of childhood cancer. For example, joint exposure to a nearby bus station and 1,3-butadiene raised the risk of cancer 12.6-fold.

In terms of policy implications, the findings suggest that current atmospheric standards for 1,3-butadiene in workplaces may not be low enough to protect from childhood cancer, Knox points out.

Chemical emission included carbon monoxide, particulate matter, nitrogen oxides, 1,3-butadiene, benzene and volatile organic compounds.

Prof Knox then looked at the postal addresses of 22,500 children who died of cancer in Britain between 1955 and 1980. To calculate the risk of cancer near particular hotspots, he looked at where the children who later died of cancer were born.

The study in the Journal of Epidemiology and Community Health found there was excess risk for children living within 0.3km of a chemical emission hotspot.

In a breakdown of emissions, 1,3-butadiene and carbon monoxide - both of which are produced by vehicle exhausts, and particularly diesel engines - were among the primary culprits, the study suggested.

Prof Knox said: "Within a short range of installations that emit these chemicals, that is within 300 metres, the risk is at least doubled and in some cases more than doubled. Not enough to worry the individual, but enough from a public health point of view."

Proximity of up to a kilometre of an emissions hotspot, such as a transport hub, also increased risk.