Showing papers by "United States Environmental Protection Agency published in 1982"
TL;DR: The evidence for inclusion of Cd among the elements known to be human carcinogens is insufficient and the impact of increasing soil Cd on the movement of CD from soil to plant to animal to human would indicate little reason for concern.
214 citations
01 Jan 1982
184 citations
TL;DR: In this article, the authors proposed a standardization of the nomenclature dealing with exposures, in which the pollutant must come into contact with the physical boundary of the person and then, exposure of person i to pollutant concentration c is viewed as two events occurring jointly.
184 citations
TL;DR: The Shielded-needle Technique for Surgically Implanting Radiofrequency Transmitters in Fish as mentioned in this paper was used for the first time in the early 80s. The Progressive Fish-Culturist: Vol. 44, No. 1, pp. 41-43
Abstract: (1982). Shielded-needle Technique for Surgically Implanting Radio-frequency Transmitters in Fish. The Progressive Fish-Culturist: Vol. 44, No. 1, pp. 41-43.
183 citations
TL;DR: In this paper, the economic implication of various replacement strategies and the effect of water quality (corrosivity) on water loss and system cost are examined. And a repair frequency analysis has been completed for distribution system maintenance events (leaks and breaks).
Abstract: Problems associated with maintaining and replacing water supply distribution systems are reviewed. Some of these problems are associated with public health, economic and spatial development of the community, and costs of repair and replacement of system components. A repair frequency analysis has been completed for distribution system maintenance events (leaks and breaks). The economic implication of various replacement strategies and the effect of water quality (corrosivity) on water loss and system cost are examined. This analysis is based on the data acquired from tne large (260 mgd; 11.39 m³/s) and one smaller (20 mgd; 0.88 m³/s) water utility. As this study shows, once a length of pipe begins to require maintenance, its maintenance rate increases exponentially. Maintenance costs soon exceed the costs of replacement. Therefore establishing a timely maintenance and replacement program is extremely important from an economic and public health viewpoint.
181 citations
TL;DR: A space saving portable mini-diluter exposure system for testing early life stages of fish and invertebrates has been developed and successfully used both in the laboratory and on-site with single chemicals and with complex effluents.
147 citations
Journal Article•
TL;DR: Trimethyltin (TMT) chloride, administered to adult male Long-Evans hooded rats, produced a unique and distinctive behavioral syndrome consisting of spontaneous seizures, tail mutilation, vocalization and hyperreactivity.
Abstract: Trimethyltin (TMT) chloride, administered to adult male Long-Evans hooded rats, produced a unique and distinctive behavioral syndrome consisting of spontaneous seizures, tail mutilation, vocalization and hyperreactivity. The LD50 for TMT was weight dependent; in large rats (e.g., 450 g), 7 mg/kg TMT produced significant weight loss and lethality, whereas in small rats (e.g., 250 g), 7 mg/kg produced neither weight loss nor lethality. TMT produced mild hypothermia and tremors. Results are discussed in comparison with kainic acid-induced morphological alterations and septal lesion-induced behavioral alterations. Histopathological evaluations of hippocampal tissue revealed cell loss that was largely confined to regio inferior pyramidal cells. TMT offers potential as a tool for investigations of limbic system structure and function.
141 citations
TL;DR: The toxicity of 175 sediment samples from Commencement Bay, Washington, was measured by the survival of marine infaunal amphipods (Rhepoxynius abronius) during ten-day exposure to test sediment as mentioned in this paper.
125 citations
TL;DR: In this paper, an interlaboratory comparison of methods to measure gaseous nitric acid is described, which includes 2 which employed chemiluminescence principles, 1 infrared, 2 diffusion denuder and 5 filtration techniques.
125 citations
TL;DR: A population dynamics model for a heterogeneous population is used to compare the effectiveness of six prevention methods for gonorrhea involving population screening and contact tracing of selected groups.
Abstract: A population dynamics model for a heterogeneous population is used to compare the effectiveness of six prevention methods for gonorrhea involving population screening and contact tracing of selected groups. The population is subdivided according to sex, sexual activity, and symptomatic or asymptomatic infection. For this model contact tracing of certain groups is more effective than general population screening.
103 citations
TL;DR: A threshold for oxygen and endrin uptake occurred between 50 and 30% of water oxygen saturation beyond which brook trout could no longer increase uptake of oxygen or endrin despite a larger respiratory volume, and the total uptake of endrin and oxygen increased as the oxygen content of the water was decreased, to 50% of saturation.
TL;DR: The appearance of individuals (including the presence of lipid reserves), growth, reproduction, and mortality as criteria for evaluating the suitability of three different food types and food concentrations for chronic life-cycle tests and for determining the maximal duration for chronic LIFE tests that will consistently yield reliable results.
Abstract: Despite the widespread use of Daphnia magna as a test organism in bioassay studies, little attention has been devoted to conditions necessary for culturing healthy animals in the laboratory or to the quality and quantity of foods required during chronic life-cycle bioassays. Growth, reproduction, and survival in daphnids are very dependent upon the quality and quantity of their food. Different algal species and artificial diets have been recommended as foods for Daphnia but the impact of these foods on the health and reproduction of test organisms has not been carefully analyzed. We used the appearance of individuals (including the presence of lipid reserves), growth, reproduction, and mortality as criteria for evaluating the suitability of three different food types and food concentrations for chronic life-cycle tests and for determining the maximal duration for chronic life-cycle tests that will consistently yield reliable results. The three foods used were (a) a 1:1 mixture of two algal species, Ankistrodesmus falcatus and Chlamydomonas reinhardtii; (b) Selenastrum capricornutum, a green alga often used in bioassay tests; and (c) trout chow (PR-11) and baker's yeast, an artificial food diet. We recommend that a diet of green algae be used in the culture and feeding of animals in life-cycle tests and that a food concentration of 1.25 mg dry weight of algae per litre of test water be provided for individual cultures daily. If the animals are fed three times a week, then 2.5 mg of algae should be used. We further recommend that life-cycle tests be run for 21 rather than 28 days to minimize the chance of low survival rates in control vessels. Methods are also described for culturing both D. magna and its food for use in life-cycle tests.
TL;DR: With a limited supply of arable land supporting an ever-increasing human population, the threat of crop loss to agricultural pests becomes continually more acute, and pesticides have become an essential component of modern agriculture.
Abstract: With a limited supply of arable land supporting an ever-increasing human population, the threat of crop loss to agricultural pests becomes continually more acute. Thus pesticides have become an essential component of modern agriculture. As competing organisms evolve resistance to commonly used agents, new and more effective poisons and repellants must constantly be developed. The fundamental problem in pesticide development is to produce chemicals that act specifically against certain organisms without adversely affecting others. Because of the similarities in the structural, metabolic and genetic components of all life forms, absolute species specificity is frequently difficult to attain. Furthermore, such toxic chemicals improperly used may engender biological effects beyond those for which they were originally manufactured.
TL;DR: In this paper, the avoidance response of rainbow trout Salmo gairdneri to copper and nickel solutions under several exposure regimes was evaluated with a computer-based data acquisition system interfaced with a linear, plexiglass chamber with countercurrent water flow.
Abstract: The avoidance response of rainbow trout Salmo gairdneri to copper and nickel solutions under several exposure regimes was evaluated with a computer-based data acquisition system interfaced with a linear, plexiglass chamber with countercurrent water flow. The best estimates of the avoidance thresholds for these metals were 6.4 μg/liter total copper and 23.9 μg/liter total nickel (95% confidence limits were 2.6–15.5 and 10.2–54.3 μg/liter, respectively). For each metal, avoidance threshold concentrations were not different whether fish were exposed in shallow or steep concentration gradients. Also, no significant differences (P > 0.05) were found when fish received multiple, increasing exposures or a single exposure in steep-gradient conditions. Rainbow trout initially avoided low copper concentrations, but were attracted to higher ones (330–390 μg/liter) during shallow-gradient tests. Under similar test conditions, fish were attracted to low nickel concentrations (about 6 μg/liter), but avoided hi...
TL;DR: Changes in normal behavior occurred within hours, but death did not exceed 50% until at least 14 days of exposure, and pesticide accumulation was determined in fenvalerate-exposed snails and permethrin-exp exposed stoneflies.
Abstract: Selected species of stoneflies, caddisflies, mayflies, dipterans, amphipods, and snails were exposed, in the laboratory, to fenvalerate or permethrin in a flowing-water test system for up to 28 days. Both behavior and death were monitored during the exposure. The LC50 values decrease with increasing exposure time. Behavior changes or death were seen at concentrations as low as 0.022 μg/liter for fenvalerate and 0.030 μg/liter for permethrin. In the fenvalerate exposures, amphipods were the most sensitive, followed by the insects and snails. In the permethrin exposures, changes in normal behavior occurred within hours, but death did not exceed 50% until at least 14 days of exposure. Pesticide accumulation was determined in fenvalerate-exposed snails and permethrin-exposed stoneflies. The range of accumulated fenvalerate in snails was 177 to 1,286 times greater than water concentration. The stoneflies' concentration factor for permethrin ranged from 43 to 570.
TL;DR: The effects of selected water pollutants and other chemicals on the activity of eight enzymes (in vitro) are summarized to give insight into the mechanism of action of toxic chemicals and have application in the development of a rapid screening procedure involving enzymes as biomonitors in analyzing water quality.
TL;DR: The second-order rate constants for the microbial transformation of a series of phenols were correlated with physicochemical properties of the phenols as mentioned in this paper, and the results showed that van der Waal's radii gave the best coefficient of determination (r2 = 0.956).
Abstract: The second-order rate constants for the microbial transformation of a series of phenols were correlated with the physicochemical properties of the phenols. The compounds studied were phenol, p-methylphenol, p-chlorophenol, p-bromophenol, p-cyanophenol, p-nitrophenol, p-acetylphenol, and p-methoxyphenol. Phenol-grown cells of Pseudomonas putida U transformed these compounds. Microbial transformation rate constants ranged from (1.5 ± 0.99) × 10−14 liter · organism−1 · h−1 for p-cyanophenol to (7.0 ± 1.3) × 10−12 liter · organism−1 · h−1 for phenol. Linear regression analyses of rate constants and electronic, steric, and hydrophobic parameters showed that van der Waal's radii gave the best coefficient of determination (r2 = 0.956). Products identified by thin-layer chromatography and liquid chromatography indicated that the phenols were microbially oxidized to the corresponding catechols.
TL;DR: Further monitoring of selected elements in seafood is considered necessary, both to delineate any temporal change in trace metal levels in locally available organisms and to ensure that concentrations of cadmium do not increase further.
TL;DR: Cysts of Giardia lamblia from symptomatic and asymptomatic carriers had similar resistances to chlorination.
Abstract: Cysts of Giardia lamblia from symptomatic and asymptomatic carriers had similar resistances to chlorination.
TL;DR: The relationship between the toxicity of 68 organic chemicals to fish and luminescent bacteria was evaluated in this article, where the feasibility of using the bacterial bioassay as a screening test in a cost-effective testing scheme was discussed.
Abstract: The relationship between the toxicity of 68 organic chemicals to fish and luminescent bacteria was evaluated. Chemicals for which 96-h median lethal concentration (LC 5 0 ) values had been measured for fathead minnows (Pimephales promelas) in flow-through tests at the U.S. Environmental Protection Agency (EPA) Environmental Research Laboratory-Duluth, Minn., were tested using the Microtox toxicity analyzer (Beckman Instruments, Inc.). The Microtox system measures the decrease in luminescence of the bacterium Photobacterium phosphoreum in response to a toxicant. The toxicity end point is the 5-min median effective concentration (EC 5 0 ), which is the concentration that causes a 50 percent reduction in light output. The correlation between fish and bacteria toxicity for a composite of industrial chemicals and pesticides had an R 2 value of 0.65. However, the relationship of these two end points for a semihomologous series of industrial chemicals appeared to be firm, with R 2 being 0.96 for common alcohols. The feasibility of using the bacterial bioassay as a screening test in a cost-effective testing scheme is discussed.
TL;DR: A centromeric heteromorphism in the chromosomes 11 is discovered which, together with the types of chromosome rearrangements thus far catalogued for TK+ / − → TK− / − mutagenesis, allows us to propose a cytogenetic distinction between the TK-competent (TK+) and Tk-deficient (Tk−) chromosome.
TL;DR: Flow-through acute lethal toxicity tests were conducted with kelthane, dursban disulfoton, pydrin and permethrin using rainbow trout Salmo gairdneri and fathead minnows Pimephales promelas in Lake Superior water.
TL;DR: Overall recuccd growth and possibly enhanced toxic effects occurred in larvae on the dry trout starter diet compared to larvae fed on Artemia, and Mercury uptake appeared influenced by the severity of toxic effects.
TL;DR: In this paper, the authors simulated the wake of a moving vehicle using a specially-constructed wind tunnel with a moving floor, where a block-shaped model vehicle was fixed in position over the test-section floor while the floor moved at the freestream air speed to produce a uniform, shear-free, approach flow.
TL;DR: In this paper, the influence of the highly turbulent region found in the lee of a model building upon plumes emitted from short stacks was examined through smoke visualization and tracer gas concentration mappings.
TL;DR: In this article, a log-linear relationship between breathing-zone air exposures and concentrations in exhaled breath was suggested for three chemicals: tetrachloroethylene, 1,1,1-trichloroethane, and vinylidene chloride.
TL;DR: In this paper, fathead minnows were exposed to three encapsulated slow-release pesticide formulations and three corresponding technical grade products used in their manufacture, and the results showed that the technical grades were more toxic than the encapsulated.
TL;DR: Growth of 28-day-old fish was the most sensitive indicator of stress during exposures to phenol, 2,4-DMP, and PCP, whereas survival was the best indicator of toxic effects from 2, 4-DCP exposure.
Abstract: Embryos of fathead minnows were more resistant to phenol, 2,4-dimethylphenol (2,4-DMP), 2,4-dichlorophenol (2,4-DCP), and pentachloro-phenol (PCP) than were larval or juvenile life stages. Growth of 28-day-old fish was the most sensitive indicator of stress during exposures to phenol, 2,4-DMP, and PCP, whereas survival was the most sensitive indicator of toxic effects from 2,4-DCP exposure. Based on these effects, the estimated maximum acceptable toxicant concentration for fathead minnows in Lake Superior water lies between 1,830 and 3,570μg/L for phenol; 1,970 and 3,110μg/L for 2,4-DMP; 290 and 460μg/L for 2,4-DCP; and 44.9 and 73.0μg/L for PCP.
TL;DR: An analysis of the residual resistance to O3 flux suggests that the gas and liquid phase pathways for O3, water vapor, and carbon dioxide are not identical.
Abstract: Hood and Dare cultivars of soybean, Glycine max (L.) Merr., vary in their foliar response to ozone. The physiological basis of this variation was investigated as a function of leaf age through an analysis of ozone flux data, leaf developmental morphology, and analogue modelling techniques. At all concentrations (0.25–0.58 μl l-1) and exposure times (1–4 h), resistance to O3 flux in the gas phase of the diffusive pathway (i.e., boundary layer and stomate) did not account fully for variation in pollutant uptake rates into the leaf interior. Ozone molecules experienced a residual resistance to diffusion that is not shared by effluxing water vapor molecules. Residual resistance to O3 flux increased with pollutant concentration and exposure time and was associated with age-dependent differences in foliar O3 response. Leaf morphology data, including stomatal frequency and the ratio of internal to external surface area, did not help explain cultivar or age-dependent differences in O3 flux. The extent of foliar injury was not consistently related to the magnitude of O3 flux into the leaf interior. An analysis of the residual resistance to O3 flux suggests that the gas and liquid phase pathways for O3, water vapor, and carbon dioxide are not identical.
TL;DR: In this paper, the authors examined the effect of moderately steep hills on plume transport and diffusion in a simulated adiabatic atmospheric boundary layer in a meteorological wind tunnel and found that the plume was adverted toward the ground.