Current views on the oral bioavailability of inorganic mercury in soil: implications for health risk assessments.

Due to the presence of mercury at a number of major contaminated sites in the United States, the bioavailability of inorganic mercury in soil following ingestion has emerged as an important public health issue. Studies of the leachability/solubility of inorganic mercury in soil have shown that it is largely immobile, thereby suggesting that it will not be readily available for absorption in the gastrointestinal tract. Ignoring the effect of the soil matrix on decreasing bioavailability may result in a substantial overprediction of risks due to ingestion of contaminated soil. This paper discusses current knowledge about the oral bioavailability of inorganic mercury in soil and offers suggestions about how these data may be applied in human health risk assessment. Though precise estimates are not available, in vivo and in vitro estimates of the bioavailability of different inorganic mercury species in different matrices suggest that the bioavailability of mercury in soil is likely to be significantly less, on the order of at least three- to tenfold, than the bioavailability of mercuric chloride, the species used to derive the toxicity criteria for inorganic mercury. Because bioavailability can vary significantly with soil type, soil aging, the presence of co-contaminants and other factors, it is suggested that whenever the fiscal aspects justify a more precise estimate of bioavailability, site-specific estimates be developed. To develop a database for identifying a less expensive and more efficient method for estimating bioavailability, it is suggested that in vivo studies be conducted concurrently with in vitro studies. However, due to the lack of precision associated with the derivation of the most widely-used health guidance value for inorganic mercury (the USEPA RfD), additional work to address the uncertainties in the RfD is recommended.

Designing a biological monitoring program to assess community exposure to chromium: conclusions of an expert panel.

The possible benefits of biological monitoring of large groups of people potentially exposed to environmental contaminants has become an area of much interest in recent years. Because chromite-ore processing residue has been found in some soils in northern New Jersey, urinary chromium monitoring of people in the community was evaluated as a potentially useful tool. In an attempt to identify those who could be exposed and to quantify the magnitude of exposure to the chromium in these soils, the New Jersey Department of Health (NJDOH) initiated a public health screening project. In 1992, the NJDOH proposed to evaluate over 4000 people who lived or worked near these sites. Volunteers were administered a questionnaire and were given a limited physical examination, and a single spot urine sample was collected. Because of the difficulties in using urinary chromium to assess low-level exposure and the potential implications of any regulatory decisions that could be based on the results of this project, a panel of experts was convened to evaluate the protocol. The panel consisted of five scientists and physicians with expertise in toxicology, dermatology, epidemiology, biological monitoring, and analytical chemistry. Like a World Health Organization group, the panel concluded that although urine biomonitoring can be useful in evaluating high levels of exposure to chromium, it is not reliable for assessing low-level exposure similar to that which may have occurred in northern New Jersey. The panel also noted that when urinary biomonitoring is to be used to assess the public's possible exposure, a large number of precautions must be taken to ensure the accuracy and usefulness of the results. The single most important recommendation was to collect a second, and perhaps a third, spot urine (or 24-h urine) sample before concluding that a person may be routinely overexposed. These suggestions are applicable to designing a biomonitoring program for nearly any environmental contaminant to which a community may be exposed. A review of scientific literature associated with biological monitoring of chromium is provided.

Implementing a university campus wellness model.

1. Using a model to plan the development of a wellness program may enhance program success. The wellness model could be used as a basic framework to implement a health promotion program at any worksite. 2. The University Wellness model depicts an individual in control and riding toward wellness. The six dimensions in the model represent a holistic view of the individual. These dimensions consider the physical, occupational, spiritual, social, intellectual, and emotional aspects of the person to illustrate how these factors impact on the wellness concept. 3. This model may apply and be of significance to other workplace situations to increase worker productivity and decrease employer costs.

A double-blind trial of feprazone in osteoarthritis of the hip.

A double-blind crossover study was carried out in 21 patients with osteoarthrosis of the hip to compare the efficacy and tolerance of feprazone (600 mg/day) and ibuprofen (1200 mg/day), each drug being given for 4 weeks. No statistically significant changes were noted in any of the objective parameters measured, but patients' subjective assessments of pain showed a significant improvement in pain levels (p less than or equal to 0.05, day and night) after feprazone. One patient, who had reported a rash at initial assessment, was withdrawn at the end of the first treatment period (on feprazone) when he developed a severe rash, 1 patient was withdrawn because of exacerbation of symptoms (on ibuprofen) and a further patient was lost to follow-up because of intercurrent illness. Both drugs were well tolerated by the other patients and the few side-effects reported were minor in nature.