Toxicology and industrial health
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Ecological risk assessment (EcoRA) generally suffers from limited application of ecological knowledge in the definition and characterization of real-world sites. Not surprisingly, most remediation decisions, which follow, have little or no relationship to the valued ecological resources of the site or the broader region. The practice has evolved to favor engineering-based mitigation strategies, which eliminate excess chemical concentrations at sites, or otherwise break exposure pathways, but which may not be ecologically beneficial. ⋯ Contaminated localities that also have poor-quality habitat may be allowed to go through a slower, less costly bioremediation process until the risk level is lowered to acceptable levels. And direct comparisons of lost resources stemming from destructive remediation options can be assessed instead of merely focusing on the lowering of contaminant concentrations. This paper presents the conceptual foundation for incorporating landscape ecology into the risk assessment process.
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Review
Determination of a site-specific reference dose for methylmercury for fish-eating populations.
Environmental risk-management decisions in the U. S. involving potential exposures to methylmercury currently use a reference dose (RfD) developed by the U. S. ⋯ Based on the analysis described above, the distribution of acceptable daily ingestion rates (RfDs) recommended to serve as the basis for site-specific risk-management decisions at Alcoa's Point Comfort Operations ranges from approximately 0.3 to 1.1 microg/kg/day, with a population median (50th percentile) of 0.5 microg/kg/day. By analogy with USEPA guidelines for the use of percentiles in applications of distributions in exposure assessments, the 10th percentile provides a reasonably conservative measure. On this basis, a site-specific RfD of 0.4 microg/kg/day is recommended.
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The neurological effects of polychlorinated biphenyls (PCBs) have been extensively investigated in humans and in animals. The main focus in human studies has been on the effects in neonates and young children, although studies of adults have also been conducted. A great deal of concern exists that even low levels of PCBs transferred to the fetus across the placenta may induce long-lasting neurological damage. ⋯ Both dioxin-like and non-dioxin-like PCB congeners have been shown to induce neurobehavioral alterations in animals. Changes in levels of neurotransmitters in various brain areas have also been observed in monkeys, rats, and mice. Of all the observed changes, the most consistent has been a decrease in dopamine content in basal ganglia and prefrontal cortex, but further research is needed before specific neurobehavioral deficits can be correlated with PCB-induced changes in specific neurotransmitters in specific brain areas.
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The U. S. Air Force has implemented the widespread use of JP-8 jet fuel in its operations, although a thorough understanding of its potential effects upon exposed personnel is unclear. ⋯ These findings demonstrate that JP-8 jet fuel exposure has significant detrimental effects on immune functions of exposed individuals. JP-8 jet fuel should be considered a potential and significant immunotoxicant. Chronic exposure to JP-8 may have serious implications to the long-term health of exposed individuals.
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Di(2-ethylhexyl)phthalate (also known as DEHP, bis(2-ethylhexyl)phthalate, or BEHP; CAS Registry Number 117-81-7) is a widely-used plasticizer. It is found in numerous plastic articles, such as paints, inks, floor tiles, upholstery, shower curtains, footwear, plastic bags, food-packaging materials, toys, and medical tubing. Not surprisingly, DEHP appears at many waste sites. ⋯ Toxicological information on toxicokinetics, biomarkers, interactions, sensitive subpopulations, reducing toxicity after exposure, and relevance to public health is also included. Environmental information encompasses physical properties, production and use, environmental fate, levels seen in the environment, analytical methods, and a listing of regulations. ATSDR, at the behest of Congress and therefore the citizenry, prepares these profiles to inform the public about site contaminants.