(NaturalNews) A new study published in the journal Environmental Health Perspectives has revealed that children are dangerously vulnerable to the effects of environmental pesticides, and for far longer than originally suspected.
Scientists at the University of California, Berkeley have discovered that children lack sufficient levels of the enzyme most responsible for detoxifying pesticides up to the age of seven and possibly for longer. Known as paraxonase or PON1, the enzyme is the most important defense the body has against organophosphate chemicals, a major ingredient of the most commonly used agricultural pesticides.
458 children from rural communities were tested for levels of the enzyme, with results showing it to be consistently around a third lower than that of the mother of each child. To compound the concern, more than 40% of the children tested positive for a genetic type that made them particularly susceptible due to the inactivity of the enzyme, whilst nearly one in ten had a genetic profile that made them 'extremely vulnerable'.
Additionally, older children are thought to be around five times more susceptible to organophosphates than adults.
"What's important about this study is that it shows that young children are potentially susceptible to certain organophosphates for a longer period of time than previously thought," said Brenda Eskenazi, UC Berkeley professor of epidemiology and director of CHAMACOS and the Center for Children's Environmental Health Research in a University of Berkeley press release.
Of particular concern to the researchers were chlorpyrifos and diazinon, pesticide chemicals still used ubiquitously in US agriculture. Pesticides have been cited as a possible cause of developmental difficulties and childhood cancers. Both the study authors and environmental health campaigners have urged a complete re-examination of the way in which home chemical products are tested for safety and of the consensus on acceptable exposure levels.
"Current EPA standards of exposure for some pesticides assume children are three to five times more susceptible than adults, and for other pesticides the standards assume no difference", wrote lead author Nina Holland.
"Our results suggest that the EPA standards need to be re-examined to determine if they are adequately protecting the most vulnerable members of the population".
Activists point to several ways in which young children are at an increased risk of physical exposure, including more rapid breathing rates, the vulnerability of having smaller bodies relative to adults and habits such as crawling on the floor and playing on the ground.
The Pesticide Action Network of North America (PANNA) has described the findings as "extremely concerning".
"Even before these results were known, EPA scientists argued that organophosphate pesticides -- posing serious threats to children's neurological development -- were too toxic to be used; we need to ban them, starting with chlorpyrifos", said PAN senior scientist Margaret Reeves, in response to the study. 
Green campaigners have suggested eating organically as an important way of reducing pesticide exposure. A University of Washington study found that children fed mostly organic produce and juice had only one-sixth of the level of organophosphate pesticide byproducts in their urine compared to children who ate conventionally grown foods. 
 Huen at al. Developmental Changes in PON1 Enzyme Activity in Young Children and Effects of PON1 Polymorphisms. Environmental Health Perspectives. 2009 June. doi: 10.1289/ehp.0900870 (available at http://dx.doi.org/)  www.panna.org/resources/panups/panup_2009062...  Curl et al. Organophosphorus pesticide exposure of urban and suburban preschool children with organic and conventional diets. Environmental Health Perspectives.. 2003 March. 111(3): 377-382.
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Michael Jolliffe is a freelance writer based in Oxford, UK.