Environmental Chemicals and Human Neurotoxicity: Magnitude, Prognosis and Markers

The neurotoxic effects of exposure to chemicals in the environment, though insufficiently recognized, remains a topic of substantial current concern and interest. Neurotoxicities may be protean; expressed as neuropathologic or as altered neurocthemical, electrophysiological or behavioural functions. The adverse effects of neurotoxicity are among the most feared ill health in humans because they adversely affect the quality of life, and have broad health, social and economic implications. Though the magnitude of neurotoxicity is not exactly known, in some advanced countries over 30 million individuals suffer from neurobehavioural illness with only 20% seeking medical attention. In the United States for instance, of the 63 million youths under 18 years of age about 10% have diagnosable neurobehavioural problems with only 20% receiving therapy. Data developed by the massive Global Burden of Disease (GBD) revealed that neurobehavioural impairment ranks only second to cancer and coronary heart disease combined. These data may indeed be more gruesome owing to the poor regulation of exposure to environmental chemicals in resource poor countries. Biomarkers play a major role in detecting, predicting and screening for neurotoxicity. Development of inexpensive and specific biomarkers of neurotoxicity is a challenge to the scientific community. Undoubtedly, the magnitude and potential severity of neurotoxicity problems make it imperative to invest in resources required to strengthen the basis for preventive intervention, the forerunner of which is the development of biomarkers for neurotoxicity at the individual and population levels. Health education on chemicals and potential for neurotoxicity is also desirable.