摘要:

TNT was mutagenic for Salmonella typhimurium without the need of a rat liver metabolic activation system (S9). The mutagenic potency of TNT decreased in proportion to the number of nitro groups that were reduced to the amino form. The presence of a nitro group on the 4 position of the diamino congener is necessary for mutagenicity. Among the active congeners, mutagenicity was generally greater for TA100 than TA98, except that for the 4‐amino congener the reverse was true. In cases when S9 was included in the assay, there was always a decrease in the number of mutants induced as compared with those without S9. Tetryl behaved like TNT, except that it was approximately three times more potent. RDX and HMX were not mutagenic under the conditions of the assay. When TNT was composted, the major metabolites identified in organic extracts of compost samples were the 2‐amino and 4‐amino congeners. An acetonitrile extract of compost was tested and found to be more mutagenic for TA98 than TA100, much like the authentic 4‐amino congener, but the amount of this congener in the extract did not account for the degree of mutagenicity.

ISSN:0098-4108    

DOI:10.1080/15287399209531632

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The Pliofilm cohort is the most intensely studied group of workers chronically exposed to benzene. Information on this cohort has been the basis for regulations and/or guidelines for occupational and environmental exposure to benzene. Rinsky et al. (1986, 1987) and Crump and Allen (1984) developed different approaches for reconstructing the exposure history of each member of the group. The predicted levels of exposure, combined with the data on the incidence of disease, have been used to estimate benzene's carcinogenic potency. In this paper, recent information from worker interviews and historical records from the National Archives and elsewhere were used to evaluate the accuracy of prior exposure estimates and to develop better ones for the cohort. The following factors were accounted for: (1) uptake of benzene due to short‐term, high‐level exposure to vapors, (2) uptake due to background concentrations in the manufacturing building, (3) uptake due to contact with the skin, (4) morbidity and mortality data on workers in the Pliofilm process, (5) the installation of industrial hygiene engineering controls, (6) extraordinarily long work weeks during the 1940s, (7) data indicating that airborne concentrations of benzene were underestimated due to inaccurate monitoring devices and the lack of adequate field calibration mated due to inaccurate monitoring devices and the lack of adequate field calibration of these devices, and (8) likely effectiveness of respirators and gloves. Our estimates suggest that Crump and Allen (1984) overestimated the exposure of workers in some job classifications and underestimated others, and that Rinsky et al. (1981, 1986) almost certainly underestimated the exposure of nearly all workers. Airborne concentrations of benzene at the St. Marys facility during the years of its operation were found (on average) to be about half those of the two Akron facilities. Our analysis indicates that short‐term, high‐level exposure to benzene vapors and dermal exposure significantly increased (by about 25–50%) the total absorbed dose of benzene for some workers. One of the key findings was that, unlike prior analyses, the three facilities probably had significantly different airborne concentrations of benzene, especially during the 1940s and 1950s.

ISSN:0098-4108    

DOI:10.1080/15287399209531633

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The percutaneous penetration of 2,4‐dichlorophenoxyacetic acid (2,4‐D) and 2,4‐D dimethylamine salt (DMA) was evaluated separately in five male volunteers who participated in both experiments. Urine samples collected for 144 h following dermal applications of 10 mg to the dorsum of the hand (9 cm2) were analyzed for 2,4‐D. Following the acid application, an average of 4.46 ± 0.849% was recovered in the urine and a significantly lower amount of 1.76 ± 0.568% following the DMA application. Significantly higher amounts of 2,4‐D DMA (7.68 ± 0.493 mg) were washed off the hand 6 h following application as compared with 2,4‐D acid (5.35 ± 0.384 mg). These results indicate that, in addition to the differences in physical and chemical properties of the two compounds that will affect absorption, the amount of the chemical absorbed is related inversely to the amount of washed off. Urinary excretion of 2,4‐D was not complete in all volunteers 144 h following either application, but in all cases it was approaching the limit of detection. An average of 84.8 ± 2.55% and 76.8 ± 8.05% of the total recovered in 144 h was recovered in the urine 96 h following 2,4‐D acid and 2,4‐D DMA application, respectively. Average, approximated half‐lives for excretion were 39.5 ± 8.1 h for the acid application and 58.5 ± 13.2 h for the DMA application.

ISSN:0098-4108    

DOI:10.1080/15287399209531634

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Percutaneous absorption of the14C‐ring‐labeled phenoxy herbicide 2,4‐D‐amine (2,4‐dichlorophenoxyacetic acid dimethylamine) was examined following topical applications of the herbicide to the palm and forearm of human volunteers. The effect of two vehicles (water and acetone) and the mosquito repellent DEET (N,N‐diethyl‐m‐toluamide) on dermal absorption of 2,4‐D‐amine also was investigated. The total percent dermal absorption was calculated from the mean percent urinary recoveries and was not corrected for nonurinary excretion. The data revealed 14 ± 4.5% (standard deviation) and 10 ± 11.5% palmar absorption of 2,4‐D‐amine applied in water, with and without DEET, respectively, and 7 ± 6.2% and 13 ± 5.0% forearm absorption of the herbicide applied in water or acetone, respectively. Soap‐and‐water skin washes conducted at 24 h posttreatment removed up to 34% of the applied dose. Successive tape strips of skin taken at 24 h posttreatment demonstrated generally decreasing herbicide levels in the outer layers. The data bring into question the complete validity of the rhesus monkey model to predict human dermal absorption.

ISSN:0098-4108    

DOI:10.1080/15287399209531635

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Age dependence in dermal absorption has been a major concern in risk assessment. Captan, a chloroalkyl thio heterocyclic fungicide, was selected for study of age dependence as representative of this class of pesticides. Dermal penetration of [14C]captan applied at 0.286 μmol/cm2was determined in young (33‐d‐old) and adult (82‐d‐old) female Fischer 344 rats in vivo and by two in vitro methods. Dermal penetration in vivo at 72 h was about 9% of the recovered dose in both young and adult rats. The percentage penetration was found to increase as dosage (0.1, 0.5, 2.7 μmol/cm2) decreased. Two in vitro methods gave variable dermal penetration values compared with in vivo results. A static system yielded twofold higher dermal penetration values compared with in vivo results for both young and adult rats. A flow system yielded higher dermal penetration values in young rats and lower penetration values in adults compared with in vivo results. Concentration in body, kidney, and liver was less in young than in adult rats given the same absorbed dosage. A physiological pharmacokinetic model was developed having a dual compartment for the treated skin and appeared to describe dermal absorption and disposition well. From this model, tissue/blood ratios of captan‐derived radioactivity for organs were found to range from 0.35 to 3.4, indicating no large uptake or binding preferences by any organ. This preliminary pharmacokinetic model summarizes the experimental findings and could provide impetus for more complex and realistic models.

ISSN:0098-4108    

DOI:10.1080/15287399209531636

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The delayed health effects from accidental exposure to bromine vapors in a group of six people were evaluated. During the acute exposure, they had only some respiratory symptoms and skin burns of first to second degree involving small areas. All were treated in one hospital and released within 1–4 d. Six to 8 wk later, some still had health complaints such as cough, shortness of breath, chest tightness, eye irritation, headache, dizziness, fatigue, and memory, sleep, and sexual disturbances, but no objective laboratory or clinical evidence of effects. Mechanisms that might have led to manifestations of such complaints 1–2 mo after the accident are discussed and possible ways to alleviate similar situations are suggested.

ISSN:0098-4108    

DOI:10.1080/15287399209531637

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287399209531631

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor