Inorganic Arsenic Exposure and Children’s Neurodevelopment: A Review of the Evidence

Abstract

Experimental studies suggest a myriad of mechanisms by which inorganic arsenic can interfere with central nervous system development, and, indeed, epidemiological studies published in the last dozen years suggest that exposure to arsenic impairs children's cognitive development. Most of the studies have been conducted in developing countries (e.g., Bangladesh, India, Mexico), where exposure to arsenic is thought to be considerably higher than it is in developed countries. This review summarizes the results of these studies, focusing in particular on issues pertinent to risk assessment, including the existence of critical windows of vulnerability, characteristics of the dose-effect relationships (e.g., the lowest adverse effect level, the functional form), the most sensitive neurodevelopmental endpoints, and potential effect modifiers such as host characteristics (e.g., methylation efficiency, sex) and co-exposures to other neurotoxicants (e.g., lead, manganese). At present, the epidemiological data do not permit firm conclusions to be drawn regarding these issues. Several factors that complicate an effort to compare the results of studies are identified, including use of a variety of indices of external and internal exposure, and inconsistency in the measurement of important potential confounders for neurodevelopmental outcomes.

Trace elements as paradigms of developmental neurotoxicants: Lead, methylmercury and arsenic

“…During recent years, evidence has emerged that children with increased exposure to arsenic suffer neurodevelopmental deficits [36], including children exposed from metallurgic industries [37]. In contrast to lead and MeHg, where validated techniques are available for exposure assessment, long-term arsenic exposure is much more difficult to determine and must rely on varying concentrations in urine samples [38].…”

Heavy metals (Pb, Cd, As and MeHg) as risk factors for cognitive dysfunction: A general review of metal mixture mechanism in brain

“…The Arsenic, also a potent neurotoxic, induces hippocampal-dependent behavioral deficits in rodent models (Martinez-Finley et al, 2011). Bellinger, (2013) proved that higher concentrations of As alters growth and development in children resulting in neurological deficits. Gong and O'Bryant, (2010) found relationship between As exposure and Alzheimer's disease.…”

Early life arsenic exposure and brain dopaminergic alterations in rats

“…The development of the brain starts prenatally and continues over a large period of time during the early postnatal period through a complex process in a well orchestrated manner. As the basic brain structures are formed and proliferation and migration of neurons take place during this time, the developing brain is vulnerable to adverse effects of environmental chemicals (Rice and Barone, 2000; Weiss, 2000; Costa, 2004; Bellinger, 2013a). A number of experimental studies have been carried out to assess the effect of arsenic, considered to be a developmental neurotoxicant during prenatal and/or lactational periods (Bellinger, 2013b).…”