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Evaluating Developmental Neurotoxicity Hazard: Better than Before

Published October 25, 2017

The developing nervous system is particularly sensitive to environmental chemicals. Unfortunately, many chemicals currently found in everyday products have not been tested for their impacts on developing nervous systems of embryos, infants and children. This is because the standard animal guideline study costs approximately one million dollars for each chemical and takes two years to complete. As a result of slow and expensive testing, less than 1% of chemicals in the environment have been evaluated for their potential to cause developmental neurotoxicity— or the toxic impacts on a developing nervous system. Impacts to proper neural development at an early age can irreversibly compromise the normal development and capacity of the human brain. Without this critical data about chemicals, it is hard to fully understand how environmental chemical exposures may impact the normal development of the nervous system at a young age.

EPA scientists are working to solve this problem by developing alternative methods to evaluate large numbers of chemicals for developmental neurotoxicity hazard. Researchers are growing neural networks in their laboratory – models that mimic cortical neuron development in humans- that will eventually be used screen thousands of chemicals that have not been evaluated for developmental neurotoxicity hazard through traditional test strategies. A paper was recently published that describes this alternative testing technology - called microelectrode array (MEA) - to the scientific community and provided methods on how it can be used to screen for neuroactive and neurotoxic chemicals. Researchers also used it to evaluate the effects of mixtures of insecticides from the same chemical family on neural activity to show dose-additive effects. Basically, researchers were looking to see whether mixtures of these insecticides have a greater impact on neural activity when combined versus individually. This will shed important light on the potential neurological impacts that chemical exposure to commercially-available, household chemicals can have on developing embryos, infants and children.