Environmental contaminant-mixture effects on CNS development, plasticity, and behavior.

Area of Science:

• Environmental toxicology
• Neurodevelopmental science
• Public health

Background:

• Environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons, can cross the placenta.
• Gestational exposure to these contaminants may lead to adverse health outcomes and affect cognitive performance.
• Specific contaminants like Benzo(a)pyrene [B(a)P] and 2,3,7,8, tetrachlorodibenzo-p-dioxin (TCDD) are well-studied examples.

Purpose of the Study:

• To provide a reference for neurotoxicological studies on the effects of environmental contaminant mixtures on development.
• To focus on the specific impacts on neurodevelopment, learning, and memory.
• To highlight potential links between contaminant exposure, vulnerability, and health disparities.

Main Methods:

• Systematic literature review of neurotoxicological studies.
• Evaluation of data on environmental contaminant mixture effects.
• Analysis of indices of development and neurodevelopment.

Main Results:

• Gestational exposure to contaminant mixtures is associated with decrements in birth index and neurodevelopmental markers.
• Observed effects include altered N-methyl-D-aspartate receptor (NMDA) mRNA expression and long-term potentiation (LTP).
• Neurobehavioral deficits were linked to learning behavior and experience-dependent activity related cytoskeletal-associated protein (Arc) expression.

Conclusions:

• Gestational exposure to environmental contaminants can negatively impact learning and memory indices.
• Hippocampal synaptic plasticity mechanisms may be targets for dysregulation during development in susceptible populations.
• The development of biomarkers for cumulative risk assessment is relevant for vulnerable, disproportionately exposed groups.