摘要:

AbstractThe toxicity ofo‐cresol to mink (Mustela vison) and European ferrets (Mustela putorius furo) was evaluated through dietary LC50 and reproduction tests. Twenty‐eight‐day LC50 tests with each species resulted in no overt signs of toxicity or mortalities, with the highest dietary concentrations being 2,520 ppm for mink and 4,536 ppm for ferrets. Mink were more sensitive too‐cresol than were ferrets, based on feed consumption, body weight data and hematologic parameters. Both species routinely consumed in excess of the estimated oral LD50 in an average day's feed consumption at the highest dietary concentration. Mink in a reproduction test exhibited no significant adverse effects at dietary concentrations as high as 1,600 ppm over 6

ISSN:0730-7268    

DOI:10.1002/etc.5620050801

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractTwelve‐day‐old bobwhite chicks were fed a diet containing 0, 5.4 or 20 ppm methylmercury chloride. The methylmercury chloride was added to the diet either in a dry, pulverized form or dissolved in acetone, propylene glycol or corn oil. Mortality was measured for 6 weeks, and samples of liver were saved for mercury analysis. Mortality was significantly lower in birds fed 20 ppm methylmercury chloride when acetone was the solvent. The reduced mortality could not be explained by effects of acetone on dietary level of mercury or on uptake of mercury into the b

ISSN:0730-7268    

DOI:10.1002/etc.5620050802

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractBetween 1947 and 1970, Olin Chemical Company discharged an estimated 4.32 × 105to 8.0 × 106kg of DDT residues (DDT, DDD and DDE) into Huntsville Spring Branch and Indian Creek in Alabama. Residents of Triana, Alabama, located approximately 10 mi downstream from the outfall, have been found to have high tissue levels of DDT residues. A comprehensive investigation of the contaminated area conducted by Tennessee Valley Authority and others in 1979 indicated extensive contamination of the ecosystem.This study investigated the environmental dynamics of DDT residues in the Huntsville Spring Branch‐Indian Creek aquatic ecosystem by assessing residue levels in sediment, water and benthic macroinvertebrates collected in September 1983 during a 3‐d period. Analytical results revealed continued heavy DDT residue contamination of all three media. Water and sediment data exhibited an exponential decrease in residues with increasing distance below the outfall. Sediments showed concentrations of residues of up to 2% by weight. Benthic macroinvertebrates also displayed high levels of DDT residues. Water bioconcentration factors ranged from 1,737 to 99,700 for total residues.DDT residue levels in Indian Creek‐Huntsville Spring Branch are still extremely high 14 years after the input of DDT was stopped. There has been no significant change in contamination levels during the 4‐year interim between this study and the previous

ISSN:0730-7268    

DOI:10.1002/etc.5620050803

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractHazard assessments of chemicals in aquatic organisms often include chronic toxicity testing. The evaluation of exposure duration and of the life stages tested according to standard test methods has led to the development of shorter chronic toxicity tests. A similar evaluation of biological endpoints (i.e., survival, growth and reproduction) could result in tests that are more economical. We analyzed endpoints for 28 chemicals and seven fish species in 34 chronic toxicity studies. When all endpoints were compared, survival was equal to or more sensitive than all other endpoints 56 to 69% of the time. Individual endpoints were more sensitive than survival 19 to 61% of the time, except for reproduction, which was always more sensitive (although there were few observations). The no observed effect concentration (NOEC) for growth could be predicted from the NOEC for survival by using interendpoint correlations (r= 0.949 to 0.974). Ratios of NOECs for survival to those for all other endpoints examined were 5 or less in 93 to 96% of the comparisons (specific endpoint comparisons ranged from 80 to 100%).The determination of the survival endpoint requires less time and money than does the determination of most other endpoints, and it appears adequate for hazard assessments in the initial stage of estimating chronic toxicity. However, a factor of at least 0.2 should be applied to the estimated no‐effect concentrations for survival to include other potential biologically significant effects at least 95% of the time. The factor of 0.2 is based on frequency analyses that resulted in the NOECs for survival being 5 times or less than the NOECs for most other endpoints about 95% of the time. Univariate analyses, however, indicated a range of 0.13 to 0.22 for the factor. A thorough evaluation of other published studies that contain endpoints other then survival should be conducted to define the appropriate factor more accuratel

ISSN:0730-7268    

DOI:10.1002/etc.5620050804

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractA test is described for the exposure of the lugwormArenicola cristatato toxicants. Embryos ofA. cristatawere exposed for 96 and 168 h to bis(triphenyltin) oxide (TPTO), triphenyltin chloride (TPTC), bis(tri‐n‐butyltin) oxide (TBTO) and tributyltin acetate (TBTA). The toxic effects were death and abnormal development of larvae. Concentrations that killed all animals were 4 μg L−1(96 h) and 2 μg L−1(168 h) TPTO; 10 μg L−1(96 h) and 5 μg L−1(168 h) TPTC; 4μg L−1(96 h) TBTO; and 10 μg L−1(96 h) and 5 μg L−1(168 h) TBTA. Abnormal morphology was caused by 0.75 μg L−1TPTO, 1 μg L−1TPTC and 5 μg L−1TBTA. Several developmental stages, from embryo to swimming larva, were exposed to TPTO. The most sensitive stages were early trochophore and early settled stage. The range of concentrations between 100% survival and 100% mortality was narrow in all tests. The exposure system is

ISSN:0730-7268    

DOI:10.1002/etc.5620050805

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractConcentrations of 0, 1 and 3 ppm endrin in dry duck mash were fed to mallards (Anas platyrhynchos) starting in December, and health and reproduction were measured the following spring and summer. One male fed 3 ppm endrin died with 2.0 ppm endrin (wet weight), a diagnostically lethal level, in its brain. Birds fed 1 ppm endrin reproduced as well as, if not better than, controls. Birds fed 1 ppm endrin had significantly greater hatching success of fertile eggs than did those fed 0 or 3 ppm, and their clutches hatched significantly earlier than did those of birds fed 3 ppm. Mallards fed 3 ppm endrin appeared to reproduce more poorly than controls, but this finding must be regarded with caution because the results of statistical tests often were not significant. Endrin accumulated in eggs to a mean of 1.1 and 2.9 ppm (wet weight) when fed to hens at 1 and 3 ppm. The concentration of endrin in the carcasses of adults was similar to that in eggs, but the concentration in the fat of adults was about 4 to 7 times higher than in eggs.

ISSN:0730-7268    

DOI:10.1002/etc.5620050806

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of daily light‐cycle duration (photoperiod) on the solar ultraviolet radiation (SUVR) ‐induced toxicity of anthracene to juvenile bluegill sunfish (Lepomis macrochirusR.) in a laboratory system under simulated sunlight was examined. Rates of acute mortality were dependent on both anthracene concentration and photoperiod. Median lethal time values calculated on the basis of accumulated SUVR exposure time (UV‐LT50) were compared with LT50 values calculated from real time of exposure (R‐LT50) to determine relative rates of phototoxic damage versus physiologic repair during periods of darkness. The comparison of these LT50 values indicated that the photoinduced toxicity of anthracene to fish was slowly repaired during periods of darkness but that enough damage accumulated over several SUVR cycles to cause acute mortality.The results from these experiments were incorporated into a relationship to predict no‐effect anthracene concentrations from the daily light‐cycle duration at one SUVR intensity. Information from acute toxicity tests was used to extrapolate to chronic no‐effect values. No‐effect anthracene concentrations in water were predicted to range from 1.2 μg/L for 24 h light:0 h dark photoperiod to 13.5 μg/L for a 6 h light: 18 h dark photoperiod. A no‐effect anthracene body burden of 131 μg/kg has been calculated for juvenile bluegill sunfish for a 16 h light:8 h dark photoperiod at an equivalent depth of 3.0 m in a typical eutrophic system. Thus, considering current natural polycyclic aromatic hydrocarbon concentrations in water and in fish tissue, there exists natural waters in which photoinduced PA

ISSN:0730-7268    

DOI:10.1002/etc.5620050807

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractIn populations in which the rate of early mortality depends primarily on the size of individuals, growth and size become important determinants of population dynamics. Models based on size and developed for fish populations can provide a means of integrating acute and chronic toxicological observations to predict changes in population size. These models predict population reductions resulting from lethality to eggs and larvae, reduced growth rate, reduced length at hatch and any behavioral or physiological changes that increase either size‐dependent or size‐independent mortality rates. The dependence of mortality rate on size may arise from developmental changes, size‐selective predation, changing energy balances or a combination of these. The biological source of mortality may dictate its mathematical expression. Since the size‐dependent mortality modeled here may arise from several common sources, it may be widespread. As a result, reductions in natural populations caused by sublethal toxic exposures may not be unusual. These results suggest that measuring sublethal reductions in early growth that result from toxic conditions may be a meaningful way of estimating potential risks to natural popu

ISSN:0730-7268    

DOI:10.1002/etc.5620050808

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY

摘要:

AbstractA safety assessment of dioctyl adipate (DOA) in freshwater environments was conducted. DOA is relatively insoluble in water and is likely to partition to sediment and biota in the aquatic environment. Biodegradation was found to be rapid and extensive under conditions simulating sewage systems and the natural environment. Measured environmental concentrations of DOA averaged less than 0.5 μg/L in natural surface waters. DOA was not acutely toxic to algae and fish at or above its water solubility of 0.78 ± 0.16 mg/L. It was acutely and chronically toxic toDaphnia magnaat 480 to 850 and 24 to 52 μg/L, respectively. A bioconcentration study with bluegill showed that DOA is not an accumulative or persistent chemical in this species. The mean 28‐d bioconcentration factor was 27. A comparison of the mean environmental water concentrations of DOA with laboratory chronic toxicity values forD. magnashowed a safety margin of approximately three orders of magnitude. The conclusion drawn from this environmental safety assessment is that, under present use and disposal patterns, DOA presents a small hazard to the freshwater aquatic environ

ISSN:0730-7268    

DOI:10.1002/etc.5620050809

出版商:Wiley Periodicals, Inc.    

年代:1986

数据来源: WILEY