ISSN:0098-4108    

DOI:10.1080/15287399309531815

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The Bhopal accident, the world's worst industrial disaster, in which nearly 40 metric tons of methyl isocyanate (MIC) was released from the Union Carbide pesticide plant, occurred nearly 10 yr ago during the night of December 2 and 3, 1984. Over 3000 people residing in areas adjacent to the plant died of pulmonary edema within 3 d of the accident. Follow‐up studies revealed pulmonary, ophthalmic, reproductive, immunologic, neurological, and hematologic toxicity among the survivors. Despite high reactivity, MIC can traverse cell membranes and reach distant organs, perhaps as a reversible conjugate with glutathione, which may explain some of the systemic effects of MIC. MIC can be degraded as a result of pyrolysis and interaction with water, but none of the breakdown products can duplicate the toxicity observed in Bhopal and in animal models. MIC may be the most toxic of all isocyanates because of its very high vapor pressure relative to other isocyanates and because of its ability to exert toxic effects on numerous organ systems.

ISSN:0098-4108    

DOI:10.1080/15287399309531816

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The transfer of109Cd from dam to offspring during gestation and lactation was studied in uniparous mice. From 70 to 210 d of age and during the subsequent reproductive period, young adult female mice received drinking water containing tracer amounts of109Cd (8 ppb total Cd) and nutrient‐sufficient or ‐deficient solid diet containing stable Cd (5 ppm Cd). The nutrient quality of the deficient diet was patterned after that consumed by lapanese women who contracted itai‐itai disease. To evaluate established maternal stores as a potential source of cadmium transfer to pups, some dams were switched to water with no109Cd and diet with an environmental or control level of cadmium (0.25 ppm Cd) during the reproductive period. The resulting pups were analyzed for109Cd at birth and at 7‐d intervals throughout the lactation period. Pup109Cd content at birth, representative of the amount transferred via the placenta during gestation, accounted for less than 1% of the total109Cd transferred during the full reproductive period. During lactation,109Cd levels in pups from dams with current109Cd exposure approximately tripled with each 7‐d interval; no significant differences occurred due to nutrient quality of the dams’ diet. For 21‐d‐old pups, 98% of the109Cd burden came from the diet of the dam, while only 2% came from her tissue stores, primarily the hepatic one. Such fractions represented a transfer per pup of about 0.01% of the oral109Cd dose ingested by the dam during the reproductive period and about 0.05% of the109Cd in her tissue stores. Overall, transfer per litter amounted to about 7% of the dietary109Cd dose absorbed and retained by the dam during that interval and about 0.2% of the109Cd from tissue stores. On lactation d 21, 90% of the total109Cd in pups was sequestered in the gastrointestinal tract. Cadmium transfer was additionally examined in multiparous mice that began a repetitive breeding program at 70 d of age at the time of introduction to the same diet/water regimens already described. Overall, females consuming nutrient‐sufficient diet experienced 5 consecutive 42‐d rounds of gestation/lactation, while their deficient diet counterparts experienced 3 nonconsecutive rounds during an equivalent period. Transfer was examined during their last gestation/ lactation experience. Throughout the lactation interval,109Cd transfer to pups was about 30% increased for multiparous versus uniparous females; however, transfer again was not significantly affected by nutrient quality of the dams’ diet. About 0.02% of the109Cd dose ingested by the dam during the last reproductive round was transferred to each 21‐d‐old pup, while about 0.08% was transferred per litter; approximately 94% of pup whole‐body109Cd was sequestered in the gastrointestinal tract. These results suggest that the itai factors of multiparity and nutrient‐deficient diet did little to increase the small amount of cadmium transferred from Japanese mothers to young during gestation and lactation and that this route of administration was not a significant source of exposure.

ISSN:0098-4108    

DOI:10.1080/15287399309531817

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Bovine alveolar macrophages were incubated up to 20 h with DQ12 quartz particles, either in untreated native form or pretreated with dipalmitoyl lecithin. The content of cathepsin B and N‐acetylglucosaminidase was measured in the culture supernatant and in the cells. After incubation, a loss of about 50% of the total cathepsin B activity in the culture dish was observed, whereas no influence on total N‐acetylglucosaminidase content occurred. Loss of cathepsin B activity was completely prevented by the pretreatment of quartz with the surfactant component dipalmitoyl lecithin. Similarly, a complete abrogation of the quartz effect on cathepsin B was noted when the cells were incubated with quartz in the presence of NH4Cl in order to prevent phagosome‐lysosome fusion. There was also no influence on cathepsin B activity when a lysosome‐rich fraction, prepared from alveolar macrophages, was incubated together with quartz. It was concluded that the reduction of cathepsin B activity was related with the intralysosomal deposition of quartz particles.

ISSN:0098-4108    

DOI:10.1080/15287399309531818

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

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

ISSN:0098-4108    

DOI:10.1080/15287399309531819

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Chromite ore processing residue (COPR) containing measurable levels of hexavalent and trivalent chromium [Cr(VI) and Cr(III), respectively] has been used to fill in low‐lying areas in Hudson County, N.J. While it has been demonstrated that direct dermal contact with solutions containing Cr(VI) may elicit allergic contact dermatitis (ACD) in previously sensitized individuals, it is unknown to what degree skin moisture may solubilize Cr(VI) from COPR adhering to skin. An accurate estimate of this extraction potential is necessary to establish COPR concentrations of Cr(VI) and Cr(III) that are protective of eliciting ACD in sensitized individuals. The purpose of this study was to measure the extractable fraction of Cr(VI) and total chromium [Cr(III) and Cr(VI)] in soils impacted by COPR using human sweat as the extractant. Human sweat was collected from seven male volunteers. Samples of COPR material containing the following Cr(VI) and total chromium concentrations were collected: Cr(VI), 16, 136, and 1240 ppm; total chromium, 932 and 6660 ppm. The samples were sieved to obtain a uniform particle size <500 μm. The samples were then mixed with human sweat at 30°C for 12 h, after which the sweat was filtered and analyzed to determine the dissolved concentration of Cr(VI) and total chromium. The data from these analyses show that no detectable levels (limit of detection = 0.010 ppm) of Cr(VI) were leached from COPR containing 16 ppm Cr(VI). At Cr(VI) concentrations of 136 and 1240 ppm, less than 0.1% of the Cr(VI) present in the COPR sample was extracted into sweat, and sweat concentrations were 0.133 ppm Cr(VI) or less. Similarly, the amount of Crtotalextracted was 0.3% or less at COPR concentrations as high as 6600 ppm Crtotaland sweat concentrations were 2.3 ppm Crtotalor less. If a minimum concentration of 10 ppm (Bagdon and Hazen, 1991) to 54 ppm (Paustenbach et al., 1992) Cr(VI) in sweat is required to elicit an ACD response in chromium‐sensitive individuals, the current study results suggest that a COPR Cr(VI) concentration of at least 10,000–54,000 ppm would be required to elicit ACD. If 500 ppm (or greater) of solubilized Cr(III) is required to elicit an ACD response (NJDEPE, 1992a), then a COPR concentration of 250,000 ppm Cr(III) or greater would be required to elicit an allergic response. These results suggest that ACD is unlikely to occur as a result of environmental exposure to the COPR.

ISSN:0098-4108    

DOI:10.1080/15287399309531820

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Croups of 12 male Wistar rats, of about 400 g body weight, were dosed with 2, 6, or 15 mg/kg of14C‐labeled pyrene, dissolved in acetone, applied to 4 cm2of a shaved area of the mid back. Three animals in each dose group were killed at 1,2, 4, and 6 d post‐dosing, and their principal organs were removed and analyzed for pyrene and [14C]pyrene equivalents. Urine and feces, as well as the area of skin to which the dose was applied, were also analyzed for [14C]pyrene equivalents. The rate of uptake from the skin was rapid (t1/20.5–0.8 d) relative to rate processes for the other organs, and about 50% of the applied dose was excreted over the 6 d of the study. The significant decrease in the fraction of the dose excreted and in the normalized amounts distributed to the various organs and tissues, as the dose increased for all chemical species measured, was strongly suggestive of nonlinear kinetics, as has been observed in previous studies. Levels of pyrene were highest in the liver, kidneys, and fat. Levels of metabolites were also high in the lung. It was evident that the dermal route of uptake was not insignificant for this model poly‐cyclic aromatic hydrocarbon and may represent a significant exposure route for exposed humans

ISSN:0098-4108    

DOI:10.1080/15287399309531821

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Although hexavalent chromium, Cr(VI), is a potent sensitizer and inducer of allergic contact dermatitis and is found in many common materials, no standard or guideline currently exists for protection against these effects in environmental exposure. There appears to be a generalized allergenic potential among the various compounds of Cr(VI). Estimates of the prevalence of Cr sensitivity in the population are uncertain, but range from about 2% of the total population in Finland to as high as 20% in U.S. populations with a dermatitis. Based on the thresholds reported for nine separate patch‐test studies and statistical analysis of the aggregate dose‐response relationship from 72 separate observations from these studies and on studies of allergic responses to bleaches and detergents, the effective threshold for elicitation of allergic contact dermatitis in sensitized populations is about 10 ppm (mg/L) Cr(VI) (as chromium) in solution. Based on evaluation of the literature on cement dermatitis, the threshold concentration of extractable Cr(VI) in solid material may be as low as 10 ppm (μg/g). For ingestion of Cr(VI), the lowest observed effect level (LOEL) dose for elicitation is 0.26 μg/kg. In calculating the threshold concentration of Cr(VI) in soil for elicitation of contact dermatitis, extractability must be taken into account.

ISSN:0098-4108    

DOI:10.1080/15287399309531822

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A COMPREHENSIVE GUIDE TO THE HAZARDOUS PROPERTIES OF CHEMICAL SUBSTANCES Edited byPradyot PatnaikVan Nostrand Reinhold, New York, 1992, 763 pp.

ISSN:0098-4108    

DOI:10.1080/15287399309531823

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287399309531814

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor