Regulations, policies, and guidelines addressing environmental exposures in early learning environments: a review.

Infants and young children under five years of age are uniquely vulnerable to certain environmental contaminants. Some of these contaminants have been found in early learning environments (ELEs), or child care and family child care settings where children spend an average of 40 hours a week. These contaminants as well as infants' and children's unique physiology, exposures, and behaviors in child care settings are the focus of this article.

Meeting report: moving upstream-evaluating adverse upstream end points for improved risk assessment and decision-making.

Background: Assessing adverse effects from environmental chemical exposure is integral to public health policies. Toxicology assays identifying early biological changes from chemical exposure are increasing our ability to evaluate links between early biological disturbances and subsequent overt downstream effects. A workshop was held to consider how the resulting data inform consideration of an "adverse effect" in the context of hazard identification and risk assessment.

In vitro toxicity and interactions of environmental contaminants (Arochlor 1254 and mercury) and immunomodulatory agents (lipopolysaccharide and cortisol) on thymocytes from lake trout (Salvelinus namaycush).

The immunotoxicity of chemical combinations commonly encountered by the lake trout (Salvelinus namaycush) immune system was the focus of this study. It was hypothesised that combinations of an environmental contaminant (mercuric chloride or Aroclor 1254) and an immunomodulatory agent (bacterial endotoxin or cortisol) might interact to produce a greater toxicity than that of the environmental contaminant alone at concentrations typically encountered in piscine blood and other tissues. Thus lake trout thymocytes were isolated and treated with mercuric chloride or Aroclor 1254 in the presence and absence of cortisol or lipopolysaccharide.