On the Use of Hair Analysis for Assessing Arsenic Intoxication.

Correlations between the concentrations of arsenic in scalp hair and in drinking water as well as in blood and/or urine have been reported. These correlations clearly show exposure⁻absorption⁻excretion relationships. In addition, arsenic metabolites such as monomethylarsonic acid and dimethylarsinic acid have been identified and quantified in these tissues and fluids, leaving little doubt that elevated levels of arsenic in the hair can reflect systemic arsenic intoxication. Consequently, hair analysis has potential merit as a screening procedure for poisoning by arsenic. However, questions regarding the exogenous versus the endogenous deposition of arsenic in the hair, and uncertainties about the normal level of arsenic in the hair remain unresolved. Pending their resolution, the determination of arsenic in hair should remain a screening tool, and clinical signs and symptoms should be employed to complete the diagnosis of arsenic poisoning.

Chelation therapy for treatment of systemic intoxication with uranium: A review.

Elevated levels of naturally occurring uranium have been found in small geographic areas throughout the world. Exposure of the general public to uranium is most often by the ingestion of food and water containing natural uranium from the hydrogeological environment, but this likelihood is remote. However, the risk is increased in regions where uranium is mined, milled, processed and/or fabricated as well as in the vicinity of former battlefields where depleted uranium munitions were deployed. Exposure in such cases is by the inhalation route. Internalized uranium is a long-term hazard the toxicity of which depends upon the dose and the dose rate as well as other parameters such as the chemical form and site of deposition of the uranium and the physiology of the host. The radiological toxicity and the chemical toxicity of uranium and its compounds are responsible for kidney damage and lung cancer. The vulnerable groups are the very young and the very old, individuals predisposed to hypertension or osteoporosis and individuals with chronic kidney disease. Those subject to long-term exposure from internalized uranium are a greater risk for the long-term implications. The accumulation of uranium may be mitigated by decreasing its absorption, distribution and deposition and increasing its elimination with chelating agents. The formation of soluble chelates may enhance the mobilization of uranium deposited in tissue and expedite its transport to and elimination from the renal system. The focus of this review is on the use of chelating agents to enhance decorporation of uranium thereby reducing the risk of intoxication.

Efficacy of hair analysis for monitoring exposure to uranium: a mini-review.

In spite of the ease with which samples may be collected and the stability of the samples after collection, the use of hair mineral analysis for monitoring environmental exposures and evaluating heavy metal poisonings has remained controversial since its initial applications for these purposes in the early 1950s. Among the major arguments against using hair mineral analysis in general were the absence of biokinetic models and/or metabolic data that adequately described the incorporation of trace elements into the hair, the absence of correlations between the concentrations of trace elements in the hair and their concentrations in other tissues, the inability to distinguish between trace elements that were deposited in the hair endogenously and those that were deposited on the hair exogenously, the absence of reliable reference ranges for interpreting the results of hair mineral analysis and a lack of standard procedures for the collecting, preparing and analyzing the hair samples. The developments of the past two decades addressing these objections are reviewed here, and arguments supporting the use of hair analysis for monitoring environmental and/or occupational exposures to uranium are made on the basis of the information presented in this review.

Chemistry and toxicology of building timbers pressure-treated with chromated copper arsenate: a review.

A recent agreement between the United States Environmental Protection Agency (USEPA) and the wood-treating industry will result in a phase-out of building timbers preserved with chromated copper arsenate (CCA). This agreement was motivated by a desire to reduce exposure to arsenic in the production, utilization and disposal of such material. The leaching of chromium, copper and arsenic from CCA-treated building timbers into water and soil and the subsequent environmental effects have been reviewed, as have the laboratory and epidemiological studies on the toxicology of CCA-treated building timbers. The benefits of the phase-out agreement are questionable because much arsenic will remain in the environment, and the alternatives to wood preservation with CCA are not without environmental consequences.