摘要:

Two inhalation studies were conducted to evaluate the possible subchronic and developmental toxic effects of n -butyl propionate. In the subchronic study, Sprague-Dawley rats (15/sex/group) were exposed to 0, 250, 750, or 1500 ppm vapor for 6 h/d, 5 d/wk for 13 wk. Five of the rats per sex per group were held after the final exposure for an 8- wk recovery period. Standard parameters of subchronic toxicity were measured throughout the study, and at the end of exposure and recovery periods, necropsies were performed, organs weighed, and tissues processed for microscopic examination. Exposure did not produce marked treatment-related deaths or adversely affect clinical signs, hematology, clinical chemistries, organ weights, or the histology of major visceral organs. The only systemic toxic effects were significant decreases in body weight, body weight gain, and feed consumption that occurred in 1500 ppm group rats. Morphologic changes were limited to the nasal cavity as evidenced by a concentration-related increased incidence and severity of olfactory epithelium degeneration in rats of the 750 and 1500 ppm groups. These degenerative microscopic alterations were primarily confined to the olfactory epithelium within the dorsal portion of the medial meatus, with lesser involvement of the olfactory mucosae overlying the tips of some of the adjacent ethmoturbinates. Both the systemic and nasal cavity effects appeared reversible after exposure ceased. In the developmental toxicity study, pregnant Sprague-Dawley rats (24/group) were exposed to 0, 500, 1000, or 2000 ppm vapor for 6 h/d on gestation d 6?15 and sacrificed on gestation d 20. All treatment-group dams exhibited significant reductions in body weight, body weight gain, and feed consumption. Gestational parameters were equivalent across all groups and there were no treatment-related developmental or teratogenic effects. The no-observed-adverse effects levels (NOAELs) determined for n butyl propionate were 250 ppm for subchronic toxicity (based on the olfactory epithelium degeneration) and 2000 ppm for developmental toxicity (no developmental effects at top dose tested). Under the conditions of this study, a NOAEL was not determined for maternal toxicity.

ISSN:1528-7394    

DOI:10.1080/00984100050120398

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Adult male and female CD rats (F0) were dosed with glutaraldehyde (GA; CAS number 111-30-8) in drinking water at concentrations of 0 (controls), 50, 250, or 1000 ppm for a 10-wk prebreed period and through mating, gestation, and lactation. Resultant Floffspring, selected to be parents of the next generation, were continued on the same regime from prebreed through lactation. Twenty-eight parental animals per sex per generation for each dose group were evaluated for clinical signs, body weight (absolute and gain), and water and food consumption. The offspring were evaluated for survival and body weight to weaning. Necropsy and light microscopic examination of removed tissues were conducted in all F0and F1

ISSN:1528-7394    

DOI:10.1080/00984100050120406

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

This study examined the dose-linearity pharmacokinetics of bisphenol A, a U.S. Environmental Protection Agency (EPA) classified endocrine disruptor, in rats following iv administration. Upon iv injection of 0.2, 0.5, 1, or 2 mg/kg, serum levels of bisphenol A declined biexponentially, with mean initial distribution and elimination half-life ranges of 4?8.2 min and 38.6?62.2 min, respectively. There were no significant alterations in the systemic clearance rate (mean range 90.1?123.6 ml/min/kg) and the steady-state volume of distribution (mean range 4.6?6.0 L/kg) as a function of the administered dose. In addition, the area under the serum concentration?time curve linearly rose as the dose was increased. In a second study, bisphenol A was given by simultaneous iv bolus injection plus infusion to steady state, and levels were measured in serum and various organs. When expressed in concentration terms (e.g., amount accumulated per gram organ weight), bisphenol A was found predominantly in the lung, followed by kidneys, thyroid, stomach, heart, spleen, testes, liver, and brain. Ratios of the organ to serum bisphenol A concentrations exceeded unity for all the organs examined (ratio range 2.0? 5.8) except for brain (ratio 0.75). Given the high systemic clearance and short elimination half-life, bisphenol A is unlikely to accumulate significantly in the rat.

ISSN:1528-7394    

DOI:10.1080/00984100050120415

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

With the ending of the Cold War, the United States and other industrialized nations are faced with the monumental task of cleaning up hazardous waste sites that were created over a 50-year period. While many factors enter into the cleanup decisions of managers of hazardous waste facilities, such as at Department of Energy sites, risk assessment plays a central role in evaluating the hazards to ecosystems and humans. Often risk from hazardous facilities is determined by identifying the risks to people, or immediate ecosystems, without regard to the size or magnitude of the surrounding ecological system or of the receptors within that system. Identifying the types of systems for contaminated systems would add immeasurably to evaluating the risks from those hazards. Using the Department of Energy (DOE) facilities as examples, it is suggested that there are three major types of systems that should be considered: (1) contaminated buildings and other facilities, (2) buffer zones that immediately surround contaminated facilities, and (3) relatively pristine or uncontaminated ecosystems that surround or are adjacent to the contaminated facilities. The relative ecological risks from remediation and restoration on these three different types of systems vary markedly, in terms of immediate effects, longterm effects, and the potential for complete recovery. Remediation on most systems containing predominately buildings and other facilities entails very little ecological risk, except for disruption of nearby ecosystems from construction and transport of materials offsite. Remediation on buffer zones, however, might cause considerable ecological damage if these systems have already undergone partial recovery, are large, and will experience physical disruption during remediation. Remediation that impacts relatively pristine or uncontaminated sites can cause major disruptions to ecosystems well beyond the value, in terms of reduced human health risk, of the restoration itself, and recovery may never be complete. Although this analysis does not consider the risks to workers from remediation, such risks should be added to the potential harm to functioning ecosystems from remediation at nearby contaminated sites. The effects of remediation on all three types of systems should be balanced when making remediation decisions. The newly proposed integrator operable unit, which surrounds the contaminated sites (operable units), and includes all other areas, provides an additional framework for considering risk, remediation, and longterm stewardship on Department of Energy lands.

ISSN:1528-7394    

DOI:10.1080/00984100050120424

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor