Showing papers by "United States Environmental Protection Agency published in 1979"

The Influence of Light and Temperature on Isoprene Emission Rates from Live Oak

Abstract: There is a growing awareness of the role of vegetation as a source of reactive hydrocarbons that may serve as photochemical oxidant precursors. A study was designed to assess independently the influence of variable light and temperature on isoprene emissions from live oak (Quercus virginiana Mill.). Plants were conditioned in a growth chamber and then transferred to an environmentally controlled gas-exchange chamber. Samples of the chamber atmosphere were collected; isoprene was concentrated cryogenically and measured by gas chromatography. A logistic function was used to model isoprene emission rates. Under regimes of low temperature (20°C) or darkness, isoprene emissions were lowest. With increasing temperature or light intensity, the rate of isoprene emission increased, reaching maxima at 800 μE m-2 s-1 and 40–44°C, respectively. Higher temperatures caused a large decrease in emissions. Since the emissions of isoprene were light-saturated at moderate intensities, temperature appeared to be the main factor controlling emissions during most of the day. Carbon lost through isoprene emissions accounted for 0.1 to 2% of the carbon fixed during photosynthesis depending on light intensity and temperature.

Sources of Nutrients and the Scale of Eutrophication Problems in Estuaries

Abstract: A comprehensive analysis of external sources of nutrients is presented including an impact, comparison of external loadings, and the resulting scale of eutrophication. The major emphasis of the analysis is on nitrogen and phosphorus.

Ingested mineral fibers: elimination in human urine

Abstract: Sediment in human urine examined by transmission electron microscopy contains amphibole fibers which originate from the ingestion of drinking water contaminated with these mineral fibers. The ingestion of filtered water results in the eventual disappearance of amphibole fibers from urine. These observations provide the first direct evidence for the passage of mineral fibers through the human gastro-intestinal mucosa under normal conditions of the alimentary canal.

The Effect of Simulated Acid Rain on Seedling Emergence and Growth of Eleven Woody Species

Abstract: Seeds of eleven woody species were exposed to 2.3 cm/wk of simulated sulfuric acid rain at pH values of 3.0, 3.5, or 4.0, or to a simulated control rain at approximately pH 5.6. All treatments also contained a neutral mixture of cations and anions based on concentrations reported for Hubbard Brook, N.H. Seeds or seedlings were subject to ambient conditions, except deposition. Seeds were planted in winter, 1977; seedlings were harvested the following summer. The dry weights of the top and roots of each seedling were recorded. Although eight species were affected by simulated acid rain, the direction and magnitude of effects varied with species and with treatment. Seedling emergence was stimulated by at least one acid treatment for four species, while root growth was inhibited for one species. Except for one species, whose emergence rate and top growth were both affected, effects were confined to one measured parameter.

Studies on brominated chemicals in the environment

Abstract: Under the Toxic Substances Control Act, data on the release of chemicals to the environment during manufacturing, processing, distribution, use and disposal are of interest. Some of our environmental measurements over the last two years have been directed to assessing the types and levels of brominated compounds released to the environment by chemical manufacturing in the states of New Jersey'.* and Arkansas.' The studies in New Jersey were initiated to assess the environmental contamination due to the manufacturing of PBBs at facilities in Bayonne and Sayerville, N.J. Samples were taken off-property of air, soil, water, wastewater, bottom sediments, and available biota. Human hair samples were also collected in nearby communities. Some of the compounds identified in New Jersey include:

Increased Susceptibility of Rainbow Trout to Infectious Hematopoietic Necrosis Virus After Exposure to Copper

Abstract: Exposure of rainbow trout to sublethal levels of copper in water increased their susceptibility to infectious hematopoietic necrosis virus. In most instances, the percent mortality was twice as great in the stressed groups compared with those groups which were not stressed but received the same virus dose. Although the level of copper in the water influenced the mortality rates, the length of exposure did not prove to be critical, as similar results were obtained after 1, 3, 5, 7, or 9 days of exposure. When different virus challenges were employed, the percent mortalities were again greater in the stressed fish at all virus doses tested, and at one dose level mortalities were noted in the stressed group but not in the untreated group.

Normal levels of cadmium in diet, urine, blood, and tissues of inhabitants of the United States.

Abstract: Cd was measured in the feces, urine, blood, and hair of U.S. inhabitants without known high Cd exposure in Chicago, Illinois, and Dallas, Texas, and in autopsy tissues of accident victims in Dallas. The average intake of Cd in food was estimated to be 13-16 microgram/d and was higher for males than females. The average levels of Cd were 0.59-0.77 microgram/l in urine, 0.09-0.11 microgram per 100 ml in blood, 0.83-1.10 microgram/g in hair, 21 microgram/g in kidney cortex, 1.2 microgram/g in liver, 0.067 microgram/g in muscle, 0.58 microgram/g in pancreas, and 0.040 microgram/g in fat. Hair Cd was higher for males than females. Cd levels increased with age in urine and all tissues and were higher in cigarette smokers than nonsmokers in urine, blood, and all tissues.

Long-Term Effects of Zinc Exposures on Brook Trout (Salvelinus fontinalis)

Abstract: Exposure of three generations of brook trout (Salvelinus fontinalis) to zinc concentrations ranging from 2.6 to 534 μg/liter produced no significant harmful effects. During a separate exposure of embryos and larvae, 1,368 μg Zn/liter significantly reduced (P = 0.05) both embryo and 12-week larval survival. An additional partial chronic exposure also resulted in significantly reduced (P = 0.05) egg chorion strength and embryo survival at 1,360 μg Zn/liter. The maximum acceptable toxicant concentration (MATC) for brook trout exposed to zinc in Lake Superior water (hardness = 45.4 mg/liter as CaCO3; pH = 7.0–7.7) lies between 534 and 1,360 μg Zn/liter. The 96-hour LC50 (median lethal) concentration for brook trout was 2,000 μg Zn/liter; thus the application factor (MATC/96-hour LC50) lies between 0.267 and 0.680. Brook trout gill, liver, kidney, and opercular bone tissues accumulated the greatest amounts of zinc. Edible muscle tissue did not accumulate zinc. Zinc loss from gill and liver from first-...

Dose-response characteristics of immunologic unresponsiveness to uv-induced tumors produced by uv irradiation of mice

Abstract: — Irradiation of mice with unfiltered FS40 sunlamps renders them susceptible to challenge with highly antigenic UV-induced skin tumors. Dose-response studies demonstrated that the susceptibility of mice to tumor challenge was directly proportional to the total dose of UV radiation, and was independent of the manner in which the dose was administered. A fractionated dose was no more effective than the same total dose given as a single treatment in inducing susceptibility to tumor challenge. The effects of even suboptimal doses of UV radiation persisted for as long as 6 months after the UV treatment.

Influences of hardness constituents on the acute toxicity of cadmium to brook trout (Salvelinus fontinalis).

Abstract: These data show that of the three major constituents characteristic of most hard waters (i.e., Ca2+, Mg2+, and the CO2 system) calcium ion, introduced either as sulfate or carbonate, is the major source of protection against cadmium toxicity. This protective effect is observed in the absence of significant cadmium precipitation. Magnesium ion, sulfate ion, sodium ion and the carbonate system provide little or no protection.

A study of soil contamination and plant lead uptake in Boston urban gardens

Abstract: This study has demonstrated a serious problem of Pb contamination in the normal environment of many urban residents. Many soil samples have been analyzed by X‐ray fluorescence spectroscopy from backyard and play areas as well as from large community gardens and playgrounds. An average Pb level of 800 ppm was found in about 900 soil samples. The elevated Pb levels are definitely traceable to widespread use of Pb paint in the past. Tissues of selected plant species grown in garden soils containing Pb levels ranging from 100–2000 ppm showed differing affinities for Pb uptake. The amount of Pb found in tissues was generally related to the soil Pb concentration but was also organ or tissue related; fruits taking up less than roots and roots less than tops. Experimental design insured that the soil was probably the sole source of Pb in this study. This points to positive translocation of Pb from soil into plant tissue.

Motor activity: a survey of methods with potential use in toxicity testing.

Abstract: Activity measurements are expected to have widespread use in toxicity testing. The multifaceted nature of motor activity will directly influence the selection of a measurement technique since the relative contribution of various motor acts to any particular measurement will depend upon the detection method. Because of the apparatus-dependent nature of motor activity measurements, it is recommended that consideration be given to how accurately the various devices measure locomotor activity. In the present paper, two types of body movement will be considered as locomotor activity: ambulation (horizontally directed movement) and rearing (vertically directed movement). Discussion focuses on the various methods currently used to record motor activity, the various components of motor activity which are likely to be recorded, and the advantages and disadvantages of these techniques for the measurement of locomotor activity. Finally, consideration is given to studies which have compared treatment effects on motor activity derived from two or more measurement techniques.

Carbon disulphide and carbonyl sulphide from biogenic sources and their contributions to the global sulphur cycle

Abstract: Estimates of the magnitude of biogenic sulphur emissions range from ∼70% of the total atmospheric sulphur burden1–7, and the chemical nature of the emissions has not been clearly established. Conway1 speculated that the principal volatile biogenic component of the sulphur cycle was hydrogen sulphide (H2S) whereas Lovelock et al.8 and Rasmussen9 have suggested that dimethyl sulphide (DMS) contributes to the apparent source deficits. Aneja et al.10 have shown that both H2S and DMS are emitted from saltmarshes. Other volatile sulphur compounds which may contribute to the sulphur burden of the atmosphere include methyl mercaptan (CH3SH)11,12, dimethyl disulphide ((CH3)2S2)11,12, carbonyl sulphide (COS)13 and carbon disulphide (CS2)14,15. We report here the discovery of CS2 and COS emanating from a saltmarsh and estimate their emission rates using emission flux reactor and bag chamber techniques. The species CS2 and COS are relatively inert in the troposphere, so may be assumed to penetrate to the stratosphere, where they may be photolysed to form the sulphur dioxide (SO2) and sulphates (SO42−) known to be present in the stratosphere. Based on the measured fluxes, we show that the emissions from marshes are important to the sulphate aerosol burden (≲19%) of the stratosphere, but not important for the tropospheric sulphur burden (≲0.2%).

Diazinon(R): Chronic Toxicity to, and Brain Acetylcholinesterase Inhibition in, the Sheepshead Minnow, Cyprinodon variegatus

Abstract: We investigated the toxicity of Diazinon to sheepshead minnows continuously exposed in flow-through toxicity tests. In the 96-hour acute test, a measured concentration of 1,400/ μg/liter was lethal to 50% of the juvenile test animals. In the partial life-cycle test, we also investigated uptake of Diazinon by sheepshead minnows and effect of Diazinon on brain acetylcholinesterase (AChE) activity. Average measured concentrations in the partial life-cycle test were nondetectable (control), 0.47, 0.98, 1.8, 3.5, and 6.5 μg of Diazinon per liter of seawater. Although the number of eggs spawned by continuously exposed fish was significantly reduced (α = 0.05) in all concentrations, no concentration tested significantly affected parental survival or fertility of eggs, nor were survival and growth of progeny affected in a subsequent 28-day test. Fish exposed to 0.47 μg/liter spawned 22.6 eggs/female-day, or 69% of control production (32.8 eggs/female-day). The number of eggs spawned by fish exposed to 6....

Influence of three sediment types on copper toxicity to the polychaete Neanthes arenaceodentata

Abstract: Adult male Neanthes arenaceodentata were exposed to 0.10±0.015 mg l-1 copper in the seawater of a continuous-flow bioassay system in the presence of a sand, a mud, a mixture of the sand and mud, and no sediment, to assess the influence of sediment type on Cu-induced mortality. The sediment type did influence mortality. The time to 50% mortality was 7.8 days without sediment, 36.5 days with sand, 54.5 days with the mixture, and 50.0 days with mud. There was no threshold Cu body burden that caused death. The mean Cu concentration per gram of N. arenaceodentata (≤24 h after death) without sediment was 270 μg, in sand 994 μg, in the mixture 1047 μg, and in mud 1464 μg. The differences in the toxic responses are discussed.

Waterborne Disease — A Status Report Emphasizing Outbreaks in Ground-Water Systemsa

Abstract: A total of 192 outbreaks of waterborne disease affecting 36,757 persons were reported in the United States during the period 1971-1977. More outbreaks occurred in nonmunicipal-water systems (70%) than municipal-water systems; however, more illness (67%) resulted from outbreaks in municipal systems. Almost half of the outbreaks (49%) and illness (42%) were caused by either the use of untreated or inadequately treated ground water. An unusually large number of waterborne outbreaks affected travelers, campers, visitors to recreational areas, and restaurant patrons during the months of May-August and involved nonmunicipal-water systems which primarily depend on ground-water sources. The major causes of outbreaks in municipal systems were contamination of the distribution system and treatment deficiencies which accounted for 68% of the outbreaks and 75% of the illness that occurred in municipal systems. Use of untreated ground water was responsible for only 10% of the municipal system outbreaks and 1% of the illness. The major cause of outbreaks in nonmunicipal systems was use of untreated ground water which accounted for 44% of the outbreaks and 44% of the illness in these systems. Treatment deficiencies, primarily inadequate and interrupted chlorination of ground-water sources, were responsible for 34% of the outbreaks and 50% of the illness in nonmunicipal-water systems.