Mechanisms underlying Children's susceptibility to environmental toxicants.

Abstract

An important public health challenge has been the need to protect children's health. To accomplish this goal, the scientific community needs scientifically based child-specific risk assessment methods. Critical to their development is the need to understand mechanisms underlying children's sensitivity to environmental toxicants. Risk is defined as the probability of adverse outcome and when applied to environmental risk assessment is usually defined as a function of both toxicity and exposure. To adequately evaluate the potential for enhanced health risks during development, both child-specific factors affecting toxicity and exposure need to be considered. In the first section of this article, example mechanisms of susceptibility relevant for toxicity assessment are identified and discussed. In the second section, examples of exposure factors that help define children's susceptibility are presented. Examples of pesticide research from the newly funded Child Health Center at the University of Washington will be given for illustration. The final section discusses the importance of putting these considerations of children's susceptibility into an overall framework for ascertaining relevancy for human risk assessment. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6

Assessment of Aflatoxin M1 and Heavy Metal Levels in Mothers Breast Milk in Famagusta, Cyprus

“…Furthermore, introduction of regulations to prevent potential contaminations is essential. Due to the increased vulnerability of infants, the determination of toxic contaminant levels in breast milk is important [61][62][63].…”

Assessment of DNA damage in workers occupationally exposed to pesticide mixtures by the alkaline comet assay

“…Most of the human data come from studies of farmers, pesticide applicators and other agricultural workers, but the clear identification of the pesticides as carcinogens with appropriate consideration of the mechanisms by which the tumours occur, or their relevance to humans has not been elucidated yet. Variations in drug-metabolising enzymes as genetic susceptibility factors, and in growth factor regulators and homeobox genes may underlie susceptibility to cancer (Faustman et al 2000). The DNA damage observed in pesticideexposed populations also plays a role in susceptibility.…”

Biomarkers of environmental toxicity and susceptibility in autism

“…Sex/age Male/female (ratio) 23/5 (4.6:1) 12/2 (6:1) 11/3 (3.7:1) Mean age in years ± Std (range) 5.8 ± 2.7 (2-13) 6.2 ± 3.1 (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) and 0.5% sodium metabisulphite; pH 5.5 at 4°C in order to maintain low redox potential under reducing condition. Cysteine was measured spectrophotometrically without the addition of dithiothreitol [21].…”

“…Further, investigators reported on the effects of mercury on neuronal development: "…mercury exposure altered cell number and cell division; these impacts have been postulated as modes of action for the observed adverse effects in neuronal development. The potential implications of such observations are evident when evaluated in context with research showing that altered cell proliferation and focal neuropathologic effects have been linked with specific neurobehavioral deficits (e.g., autism)" [13]. Finally, the Collaborative on Health and the Environment's Learning and Developmental Disabilities recently published a consensus statement reporting that there is no doubt mercury exposure may produce autism spectrum disorders [14].…”