Showing papers by "United States Environmental Protection Agency published in 1977"

The National Institute for Occupational Safety and Health.

Abstract: Background This document recommends practices for extended use and limited reuse of NIOSH-certi ed N95 ltering facepiece respirators (commonly called “N95 respirators”). The recommendations are intended for use by professionals who manage respiratory protection programs in healthcare institutions to protect health care workers from job-related risks of exposure to infectious respiratory illnesses.

Methods for Calculating an LC 50

Abstract: A variety of graphical and computational methods can be used to derive a median lethal concentration (LC 5 0 ) from concentration-mortality data produced by an acute mortality test. In the selection of a method, practical considerations should receive as much attention as the usual theoretical and statistical considerations. No method should be used that does not calculate both the LC 5 0 and its 95 percent confidence limits. Unfortunately, several computational methods will not calculate an LC 5 0 from some concentration-mortality data that are practically and statistically useful to aquatic toxicologists. Useful, statistically sound information about the LC 5 0 and its 95 percent confidence limits can be calculated from the data produced by any acute mortality test that meets published criteria of acceptability, by using an internally consistent scheme based on the moving average method and the binomial test.

Singlet oxygen in natural waters

Abstract: MANY studies have shown that singlet molecular oxygen can oxidise a variety of organic substances1–7. These studies have included biologically important compounds present in the aquatic environment such as amino acids4,7 and pollutants like polycyclic aromatic hydrocarbons5 and pesticides6. No data, however, have been obtained to demonstrate that reactions involving singlet oxygen (often called oxygenations) are sufficiently rapid to be significant in natural waters. The most likely mechanism for oxygenation in the environment was originally proposed by Kautsky8 by which light energy absorbed by a sensitiser is transferred to ground-state oxygen to form singlet oxygen, which in turn reacts with the organic substance, or ‘acceptor’ (A), to form a peroxide. Here we present evidence that rapid photochemical generation of singlet oxygen occurs in inland and coastal water bodies of the south-eastern United States.

Tris(2,3-dibromopropyl) phosphate: mutagenicity of a widely used flame retardant

Abstract: Tris(2,3-dibromopropyl) phosphate, a widely used flame-retardant additive for textiles, is mutagenic to histidine-requiring strains of Salmonella typhimurium. Extracts of fabrics treated with this compound are also capable of inducing mutations in these bacterial strains.

Effects of environmental factors on radiocadmium uptake by four species of marine bivalves

Abstract: Temperature, salinity, bottom-sediment type, and zinc concentration all influenced Cd uptake by 4 marine bivalves (Mya arenaria, Mytilus edulis, Mulinia lateralis and Nucula proxima) in short-term static assay systems using 109Cd as a tracer. The experimental system consisted of aquaria containing 20 l of seawater maintained under controlled light and temperature conditions. The water contained either 5 or 20 μg/l Cd and tracer. Distribution and kinetics of the metal were monitored in the water column and organisms. The results demonstrate that Cd uptake rates differed widely among the organisms tested. An increase in temperature increased Cd uptake rate by all test organisms. A decrease in salinity increased Cd uptake by all organisms tested. The presence of bottom sediment depresses Cd accumulation in some benthic animals. Zinc in concentrations of 0.5 mg/l substantially decreased Cd uptake by Mytilus edulis and Mulinia lateralis. It is suggested that all important species and environmental variables be considered when studying heavy-metal uptake by marine organisms or when establishing water-quality criteria.

Acute toxicities of Cd2+, Cr+6, Hg2+, Ni2+ and Zn2+ to estuarine macrofauna

Abstract: Static acute toxicity bioassays were conducted at 20 degrees C and 20 o/33 salinity with CdCl2-2 1/2 H20, K2CrO4, HgCl2, NiCl2-6H2O, and ZnCl2 using adults of starfish, Asterias forbesi; sandworm, Nereis virens; hermit crab, Pagurus longicarpus; softshell clam, Mya arenaria; mudsnail, Nassarius obsoletus; and mummichog, Fundulus heteroclitus, a fish. Concentrations (mg/L metal) fatal to 50% of the organisms in 168 hr ranged from 0.004 (clam) to 0.8 (mummichog) for mercury; 0.7 (clam, worm, crab and starfish) to 40.0 (mummichog) for cadimium; 0.2 (crab) to 52.0 (mummichog) for zinc; 0.7 (sandworm) to 44.0 (mummichog) for hexavalent chromium; and 13.0 (starfish) to 150.0 (mummichog) for nickel. Biocidal action was restricted to a relatively narrow range for all species-metals combinations tested: i.e., mean LC-75/LC-25 rations for individual metals at 168 hr ranged between 2.82 (Zn) and 6.02 (Cd); for individual species this ratio extended from 2.76 (fish) to 4.46 (clam). It appears that acute toxicity evaluation of potentially hazardous metals in saline environments requires utilization of at least several representative species from divergent taxonomic and ecological niches.

An exhaustive steam-distillation and solvent-extraction unit for pesticides and industrial chemicals.

Abstract: on techniques use an external steam generator that jets steam into the sample and collects the chemicals by condensing the steam and volatile chemicals in a cooled flask. Although steam distillation is commonly used in flavor and drug analysis (NIELSON and KRYGER 1969; SIEK and LINDSAY 1968; TAMSMA et al. 1969), the large surface areas of the glassware and the low collection efficiency of conventional apparatus have prevented the use of steam distillation as a quantitative technique in the analysis of trace amounts of less volatile organic chemicals. Despite the apparent shortcomings of steam distillation, this technique offers unique possibilities in trace analysis. The vapor pressures of many pesticides and industrial chemicals are appreciably greater than those of water-soluble chemicals in wastewaters and sediments (MACKAY and WOLKOFF 1973; STORHERR et al. 1971). Moreover, the vapor pressures of many trace chemicals are greater than those of the high molecular weight triglyceride lipids in fish and warm-blooded animals. Because exhaustive solvent-extracti on technique~ remove lipids, waxes, and related natural products, as well as the trace contaminants, extensive chromatographic separations are necessary before the extracts can be analyzed for the trace chemicals. We have developed a modified Nielsen-Kryger steam-distillati on apparatus that provides exhaustive distillation of pesticides and industrial chemicals from water, sediments, and tissue and the simultaneous extractior of the distillate by a small volume of organic solvent. The extract is generally suitable for direct gas-liquid chromatography (GLC) analysis without the time-consuming concentration and cleanup procedures.

Neoplasia in soft‐shell clams (my a arenaria) collected from oil‐impacted sites

Abstract: The Histopathology Unit of our laboratory has been involved for the past 7 years in the histopathologic examination of marine invertebrates collected from various oil spill sites along the coastal areas of the United States (TABLE 1). Of the 18 species of marine invertebrates examined from 1 1 oil spill sites, only soft-shell clams, Mya arenaria, collected from two oil spill sites, Long Cove, Searsport, and Harpswell Neck in Maine (FIGURES I & 2), have consistently shown neoplasms. The histopathologic results of the Long Cove surveys performed prior to 1975 were reported by Barry and Yevich.l Information on the ecologic and chemical evaluation of the Long Cove area is available in papers by Dow and Hurst2 and Mayo et al. No ecologic and chemical evaluation was performed on the Harpswell Neck area.

Colonization of the botanical environment by Klebsiella isolates of pathogenic origin.

Abstract: Growth, survival, and pathogenicity of Klebsiella growing in and on environmental foci were examined. Total coliforms present in raw wastes from pulp mills were in excess of 105/ml, and 60 to 80% were Klebsiella. Fecal coliform counts ranged from 101 to 105/ml. Klebsiella isolates from industrial effluents and a variety of human and bovine mastitis origins multiplied in pulp waste and commonly exceeded 106 cells per ml. Pathogenic isolates also multiplied in dilute aqueous extracts of sawdust to comparable levels. Klebsiella strains from vegetable surfaces and human infections grew rapidly on the surfaces of potatoes and lettuce and exceeded 103 organisms per g of surface peel and leaf after a 24h incubation at room temperature. After 7 weeks on potatoes stored at 5°C, some 10 to 30% of the day 1 Klebsiella counts were recoverable. Three Klebsiella isolates of pathogenic origin were passed 45 times through sterile pulp effluent (270 generations), and mean lethal dose levels in mice were periodically monitored. In two instances, a significant decrease in virulence was noted after 15 to 26 passes (90 to 156 generations). The third culture, of bovine mastitis origin, retained its original mean lethal dose value. Botanical milieu provided suitable habitats for the multiplication and colonization of Klebsiella isolates of disease origins in the same manner as indigenous isolates. Aquatic environments polluted with botanical material served as potential reservoirs for perpetuating the growth and spread of opportunistic Klebsiella pathogens that may ultimately colonize animals, humans, and aquatic organisms.

Investigation of mutagenic effects of products of ozonation reactions in water

Abstract: Of the 28 compounds that were ozonated in the study and screened by the in vitro microbiologic mutagenic procedures, only seven indicated some level of activity. Ethanol was active in Saccharomyces after prolonged ozonation; metabolic activation resulted in significantly reduced activity. Benzidine was mutagenic in Salmonella before and after ozonation, but conflicting results were obtained in several repeat experiments in Saccharomyces after ozonation. Phenol, hydroquinone, 2,4-dinitrotoluene, and nitrilotriacetic acid gave anomalous results in Saccharomyces after ozonation; although elevated activity was indicated in some of the experiments, it was not dose related. After ozonation, 1,1-diphenylhydrazine indicated weakly positive activity in one test in Salmonella, but no activity was found in a repeat sample. In the yeast, generally elevated activity after ozonation was not dose related. Thus, in general, ozonation under the conditions of this study did not induce substantial mutagenic activity in the compounds studied in the Saccharomyces and Salmonella microbial systems. Where activity was indicated, it usually resulted after prolonged exposure to ozone, was not dose related, and was not repeatable in some cases. Generally, nitrogenous compounds seemed to have a greater propensity to produce activity after ozonation than did compounds without nitrogen. It is possible that more activity would more » have been detected in some examples had higher compound dosages been employed where water solubility was a limiting factor. Continuation studies are expected to provide additional information by utilizing cosolvents to increase water solubility of such compounds as benzo(a)pyrene and by pursuing the identification of more of the ozonation products. Chlorine dioxide will also be investigated in similar experiments, and additional representative compounds will be considered. « less

Kepone-induced scoliosis and its histological consequences in fish

Abstract: Scoliosis in fish is caused by several diverse agents that possibly act on the central nervous system, neuromuscular junctions, or ionic metabolism. The organochlorine pesticide Kepone induces scoliosis in the sheepshead minnow. Some effects associated with Kepone-induced scoliosis in these fish are disruption of myotomal patterns, inter- and intramuscular hemorrhage, fractured centra of vertebrae, and death. The histological syndrome of Kepone poisoning in fish and the clinical syndrome in humans suggest that the nervous system is a primary target for Kepone and that scoliosis is a secondary effect of Kepone poisoning in fish.

Acute toxicities of selected heavy metals to the softshell clam, Mya arenaria.

Abstract: Static acute toxicity bioassays with adult softshell clams and salts of copper, cadmium, zinc, lead, manganese, and nickel were conducted at 30 ‰ salinity and 22°C. Concentrations fatal to 50% in 168 hours, in mg/l (ppm) metal added at start, were 0.035 for Cu, 0.150 for Cd, 1.55 for Zn, 8.80 for Pb, 300.0 for Mn, and >50.0 for Ni. Additional tests were conducted with Zn2+ and Cu2+ at 30 ‰ during fall (17.5°C) and winter (4°C); clams displayed increasing survival with decreasing temperature. For Cu, LC-50 (336 hr) values at 17°C and 4°C were 0.086 and >3.00 mg/l, respectively; for Zn these were 2.65 and >25.0, respectively.

Kepone® bioconcentration, accumulation, loss, and transfer through estuarine food chains

Abstract: Accumulation, transfer, and loss of Kepone in estuarine organisms were studied in laboratory bioassays. Kepone was bioconcentrated by oysters (Crassostrea virginica), mysids (Mysidopsis bahia), grass shrimp (Palaemonetes pugio), sheepshead minnows (Cyprinodon variegatus), and spot (Leiostomus xanthurus), from concentrations as low as 0.023 μg/l seawater. Bioconcentration factors ranged from 10 to 340 in static exposures and 900 to 13,500 in flow-through bioassays, and were dependent on species and exposure duration. Depuration of Kepone from oysters in Kepone-free water was rapid (35% loss in 24 hours); however, depuration of Kepone was slow in crustaceans and fish, with tissue concentrations decreasing 30–50% in 24–28 days. Oysters, fedChlorococcum containing approximately 34 μg Kepone/g wet weight, attained 0.21 μg Kepone/g (wet tissue) in 14 days, but when fed Kepone-free plankton, depurated Kepone to below detectable concentrations ( 85%) quantities of Kepone transferred from prey to predatory fish.

Chemical and biological relationships relevant to the effect of acid rainfall on the soil-plant system

Abstract: This paper deals with problems concerning measurements of rainfall acidity and interpretation in terms of possible effects on the soil-plant system. The theory of acidity relationships of the carbon dioxide-bicarbonate equilibria and its effect on rainfall acidity measurements is given. The relationship of a cation-anion balance model of acidity in rainfall to plant nutrient uptake processes is discussed, along with the relationship of this model to a rainfall acidity model previously proposed in the literature. These considerations lead to the conclusion that average H+ concentration calculated from pH measurements is not a satisfactory method of determining H+ loading from rainfall if the rain is not consistently acid. Calculating loading from H+ minus HCO3 − , strong acid anions minus basic cations, or net titratable acidity is suggested. The flux of H+ ions in soil systems due to plant uptake processes and sulfur and nitrogen cycling is considered. H+ is produced by oxidation of reduced sulfur and nitrogen compounds mineralized during decomposition of organic matter. Plant uptake processes may result in production of either H+ or OH− ions. Fluxes of H+ from these processes are much greater than rainfall H+ inputs, complicating measurement and interpretation of rainfall effects. The soil acidifying potential due to the oxidation of the NH4 + rainfall is examined, with the conclusion that acidity from this source is of a similar magnitude to direct H+ inputs common in rainfall.

Mysidopsis bahia: An estuarine species suitable for life-cycle toxicity tests to determine the effects of a pollutant

Abstract: This study documents the successful use of a mysid, Mysidopsis bahia, for life-cycle toxicity tests. These tests were conducted to determine acute and chronic toxicities of metal (cadmium) and pesticide (Kepone). Delay inthe formation of mysid brood pouches and release of young were noted in low concentrations ≤6.4 μg cadmium/litre. Fewer young produced per female and decreased growth were other indicators of effects of Kepone.

Impairment of Antipredator Behavior in Palaemonetes pugio by Exposure to Sublethal Doses of Parathion

Abstract: Grass shrimp, Palaemonetes pugio, when exposed to sublethal concentrations of methyl or ethyl parathion, become more susceptible to predation by gulf killifish, Fundulus grandis. An increase in spontaneous activity renders them more easily detected by a predator, and they fatigue more quickly when being pursued. Such changes in a multi-prey community could result in altered predator preferences and subsequently could change community structure and trophic relationships.

General Motors sulfate dispersion experiment: summary of EPA measurements

Abstract: In October 1975, General Motors sponsored a study of sulfate exposures utilizing a fleet of catalyst equipped motor vehicles in controlled, simulated, highway driving conditions. This paper reports some EPA sponsored measurements. Sulfuric acid aerosol, in the Aitken nuclei mode, geometric mean diameter (GMD) of about 0.02 µm, is emitted in the exhaust of catalyst equipped vehicles. Measurement of sulfuric acid 20 m downwind of the roadway indicated a lack of complete neutralization by ammonia. When the wind was perpendicular to the roadway there was little coagulation of sulfuric acid into the accumulation mode, GMD of about 0.24 µm From measurement of the mass flow rate of aerosol sulfur from the simulated freeway, the aerosol sulfur emission rate per car was determined to be 3.5 ± 0.8 µg/m (5.6 ±1.3 mg/mile) corresponding to a 12 ± 3% conversion of fuel sulfur into emitted aerosol sulfur.

Activated Sludge-Unified System Design and Operation

Abstract: A unique procedure for designing and operating the activated sludge aeration basin/clarifier system is developed using the settling flux approach. A least-coast design procedure, utilizing batch settling tests and the state point concept, produces a design solution which minimizes capital and operational costs. In addition, the settling flux approach provides the plant operator with a tool for control and operation of the clarifer/thickener to improve treatment efficiencies and prevent operational failures.

Acute toxicity to and bioconcentration of endosulfan by estuarine animals

Abstract: Acute (96-h) flow-through toxicity tests with endosulfan (Thiodan) were conducted with several estuarine animals. The test species and their 96-h lethal concentration for 50 percent of the organisms (LC 5 0 ) values were: pink shrimp (Penaeus duorarum), 0.04 μg/litre; grass shrimp (Palaemonetes pugio), 1.3 μg/litre; pinfish (Lagodon rhomboides), 0.3 μg/litre; spot (Leiostomus xanthurus), 0.09 μg/litre; and striped mullet (Mugil cephalus), 0.38 μg/litre. In a 56-day bioconcentration study (28-day uptake, 28-day depuration), striped mullet were exposed to 0.008 and 0.08 μg endosulfan/litre seawater. The two endosulfan isomers (endosulfan I and II) were rapidly metabolized to endosulfan sulfate; only trace amounts of each isomer were detected in edible tissue or offal of mullet exposed to 0.08 μg/litre (0.035 μg/litre measured) for 28 days. Maximum bioconcentration factors of endosulfan were 2249 in edible tissue and 2755 in whole-body analyses. After 48 h in pesticide-free seawater, endosulfan was not detected in the previously exposed mullet. Our studies suggest that endosulfan in the estuarine environment would be a hazard because of its acute toxicity and bioconcentration potential, but animals surviving exposure and moving to areas free of endosulfan would lose the chemical rapidly.

Mortality rates from size distributions

Abstract: A population model explicitly describing the dynamics of an arbitrary population size distribution is presented. One consequence of the model is an equation for the exact shape of the size distribution of a stationary or steady-state population. The shape is expressed as a function of sizespecific mortality and growth rates. From the equation, various mortality estimation formulas can be derived, two of which are discussed in detail. One of the methods permits estimation of size-specific mortality rates without the assumption of a theoretical growth model.

The importance of physical and biotic scaling to the experimental simulation of a coastal marine ecosystem

Abstract: A marine microcosm, consisting of a pelagic phase interacting with a benthic phase, is described. Variations in water turnover, turbulence, incident radiation and ratio of pelagic volume to benthic surface area are shown to have significant effects on the behavior of these microcosms. It is argued that the inclusion and accurate simulation of appropriate levels of these variables is important in microcosm studies designed to study the dynamics of natural systems.