University of Southern Denmark Potential developmental neurotoxicity of pesticides used in Europe

Pesticides used in agriculture are designed to protect crops against unwanted species, such as weeds, insects, and fungus. Many compounds target the nervous system of insect pests. Because of the similarity in brain biochemistry, such pesticides may also be neurotoxic to humans. Concerns have been raised that the developing brain may be particularly vulnerable to adverse effects of neurotoxic pesticides. Current requirements for safety testing do not include developmental neurotoxicity. We therefore undertook a systematic evaluation of published evidence on neurotoxicity of pesticides in current use, with specific emphasis on risks during early development. Epidemiologic studies show associations with neurodevelopmental deficits, but mainly deal with mixed exposures to pesticides. Laboratory experimental studies using model compounds suggest that many pesticides currently used in Europe – including organophosphates, carbamates, pyrethroids, ethylenebisdithiocarbamates, and chlorophenoxy herbicides – can cause neurodevelopmental toxicity. Adverse effects on brain development can be severe and irreversible. Prevention should therefore be a public health priority. The occurrence of residues in food and other types of human exposures should be prevented with regard to the pesticide groups that are known to be neurotoxic. For other substances, given their widespread use and the unique vulnerability of the developing brain, the general lack of data on developmental neurotoxicity calls for investment in targeted research. While awaiting more definite evidence, existing uncertainties should be considered in light of the need for precautionary action to protect brain development. Introduction Pesticides are used widely in agriculture to maintain and increase crop yields, and they are also applied in homes and gardens. The annual application of synthetic pesticides to food crops in the EU exceeds 140,000 tonnes [1], an amount that corresponds to 280 grams per EU citizen per year. Despite European policies to reduce pesticide use, EU statistics data for 1992–2003 show that the annual pesticide consumption has not decreased [1]. A few hundred different compounds are authorised for use in all EU member states, but a similar number of pesticides is in current use in different EU countries and are being evaluated for possible authorisation in all of EU. Approximately 300 different pesticides have been reported as contaminants of food products of European origin [2]. Up to 50 percent of fruits, vegetables and cereals grown in the European Union are known to contain pesticide residues [2], but only a small fraction of pesticides in current use are included in the monitoring programmes. Nonetheless, one out of twenty food items is Published: 22 October 2008 Environmental Health 2008, 7:50 doi:10.1186/1476-069X-7-50 Received: 26 August 2008 Accepted: 22 October 2008 This article is available from: http://www.ehjournal. net/content/7/1/50 © 2008 Bjørling-Poulsen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.