Common weed killers have been linked to cancers in exposed workers. Women whose jobs regularly expose them to weed killers may have a higher-than-normal risk of a particular form of brain cancer, results of a US study suggest. Researchers writing in the American Journal of Epidemiology reported that among more than 1,400 US adults with and without brain cancer, women who had ever been exposed to herbicides at work had a two-fold higher risk of meningioma than women with no such exposure. Meningiomas are slow-growing tumours in the tissue covering the brain and spinal cord. In a separate study, US researchers found that a chemical that comes from the pesticide DDT may raise a man’s risk of developing testicular cancer. They found a clear link between testicular cancer and DDE, a breakdown product of DDT. Men with the highest levels of DDE were 70 per cent more likely to have developed testicular cancer than those with the lowest levels, according to the study published in May 2008 in the Journal of the National Cancer Institute.

Claudine M Samanic and others. Occupational exposure to pesticides and risk of adult brain tumors, American Journal of Epidemiology, volume 167, pages 976-985, 2008 [abstract]
Katherine A McGlynn and others. Persistent organochlorine pesticides and risk of testicular germ cell tumors, Journal of the National Cancer Institute, volume 100, pages 663-671, 2008 [abstract]. Risks 355.