Around 2010, American epidemiological studies showed a link between exposure to neurotoxicological micropollutants such as organophosphorus pesticides and learning and developmental disorders such as attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder in children. The Department of Environment and Health took the initiative to set up the EU project Development Neurotoxicity Assessment of Mixtures in Children (DENAMIC) to examine these links in more detail.

For this research, the researchers developed a new assay: they exposed zebra fish to combinations of pesticides and studied the deviations in the metabolic pattern of the fish and the behaviour of the larvae. In order to ascertain the metabolic pattern, they examined approximately 400 metabolic substances which are related to neurotransmitters. They monitored the behaviour of larvae, such as their speed of movement, size and time of hatching, with a camera.

To keep the measurements manageable and cheap, they did so using high-throughput methods. This enabled the researchers to find out how eggs and larvae respond to the various pesticides and combinations of these pesticides. The EU project was completed by the end of 2015, but the department is continuing to expose zebra fish to organic micropollutants which potentially lead to developmental and behavioural disorders and trying to discover the underlying mechanism.

DENAMIC project website


Prof. dr Pim Leonards