Among the teens who had higher concentrations of pesticides in their blood, a clear influence on their sexual development was established.
The team, led by doctor Kim Croes, was given access to data provided by the Pupil Guidance Centre (CLB) on the hormonal development of 14 and 15 year olds. They compared the records of 600 students and measured the concentrations of pesticides in their body. The effects of the pesticides were then linked to the development of genital and sex hormones, testosterone or estradiol.
Strikingly, pesticides like HCB and DDE, which have been banned since 1984, are still very much present in Flemish children. “This is due to the substances still being released in our soil and rivers”, according to Dr Croes. She advises against eating self-caught river fish and eggs laid by chickens pottering about on potentially contaminated ground.
According to the study, both banned substances and widely used pesticides mess up the hormonal balance in teenagers. HCB and DDE for instance, speed up the sexual development of boys, but slow it down for girls. Organophosphorus compounds on the other hand, slow down the development in both sexes. These kinds of pesticides are still used for horticultural purposes and are also present in products sold to the general public.
Degradation product paradichlorophel, present in moth balls, toilet rim blocks and air fresheners, seems to the affect the thyroid hormones. “Luckily, the use of this product will be limited to 1% in June 2015 thanks to new European legislation. But, it is probably safer to avoid it completely”, stated Dr Croes.