摘要:

AbstractEnvironmental Chemistry describes the world around us — a dynamic world of chemicals which become distributed between earth, water, atmosphere, and biota and transformed by natural reagents. The subject is far from new; until the age of synthetics, chemistry itself was based predominantly on the natural environment. Its present renaissance has been stimulated largely by the promise of assessment and control of toxic hazards and pollution, but the predictability, novel chemistry, and wide applications already apparent may prove at least as important. Just as synthetic chemistry revolutionized the lives of recent generations, environmental chemistry can provide a better future for all Earth's inhabitant

ISSN:0730-7268    

DOI:10.1002/etc.5620010102

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractHydroquinone is readily degraded by an acclimated activated sludge unit when present at concentrations of 100 mg/L in synthetic photographic or synthetic domestic wastes. A number of pure cultures of yeasts, fungi, and bacteria were isolated from soil and sludges which can utilize hydroquinone as a sole carbon source.1,4‐Benzoquinone, 2‐hydroxy‐1,4‐benzoquinone, and β‐ketoadipic acid were detected as minor components during the biodegradation of hydroquinone by pure cultures, but they did not persist. The total organic carbon during biodegradation was accounted for within experimental error by hydroxylated aromatic compounds. At pH 7 or below, biodegradation by pure cultures or sludges leaves only ca. 2.1% of the total organic carbon in solution after 3–5 days. This value is comparable to values observed for easily assimilated substrates under similar conditions.At higher pH and in the absence of sulfite, some humic acids may be formed by chemical oxidation if the inoculum is low; these materials resist bi

ISSN:0730-7268    

DOI:10.1002/etc.5620010103

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe transfer of organic pollutants into the atmosphere is discussed from the standpoint of mechanisms involved, factors influencing rates of volatilization, and progress in developing models for predicting transfer rates. The volatilization rate of soil‐incorporated chemicals is controlled by vapor pressure of the chemical in soil and by its rate of movement to the soil surface by diffusion or by a combination of diffusion and convection in evaporating water. Vapor pressures of organic chemicals are greatly decreased by their interaction with soil mainly due to adsorption. The magnitude of the adsorption effect depends upon the nature of the chemical, its concentration, the soil water content and soil properties, such as organic matter and clay content. Vaporization of chemicals in soil or from disposal sites covered with soil can be estimated from considerations of the physical and chemical factors controlling concentrations at the soil surface and most models developed to estimate volatilization rates are based upon equations describing the rate of movement of the chemical to the soil surface by diffusion and/or convection. Considerable progress has been made in developing laboratory based models for predicting volatilization from soil. Since volatilization of soil‐incorporated chemicals is controlled mainly by factors within the soil, predictions from laboratory based mathematical models should be sufficiently accurate for many purpo

ISSN:0730-7268    

DOI:10.1002/etc.5620010104

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractOrganophosphorus and carbamate pesticides are cholinesterase (ChE) inhibiting chemicals that have been responsible for avian die‐offs. Identification of chemicals implicated in these die‐offs is difficult and sometimes conclusions are solely circumstantial. However, when marked depression (inhibition) of brain ChE activity accompanies organophosphorus or carbamate residues in body tissues or ingesta, cause‐effect diagnosis is enhanced. To achieve this end, normal brain ChE activity is estimated for controls of the affected species and then die‐off specimens are individually evaluated for evidence of ChE inhibition. This approach to evaluation of antiChE poisoning may also be used to monitor exposure of vertebrates to field application of organophosphorus or carbamate pesticides. Problems associated with this kind of evaluation, and the main topic of this report, include variability of brain ChE activity among species, postmortem influences of ambient conditions (storage or field) on ChE activity, and differential patterns of ChE activity when inhibited by organophosphorus or carbamate compounds. Other topics discussed are the ChE assay procedure, example case reports and interpretation, and research needed for improving the diagnostic utility of ChE activity in a field si

ISSN:0730-7268    

DOI:10.1002/etc.5620010105

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractStudies from this laboratory have focused on sublethal physiological effects of small amounts of ingested crude oil in young herring gulls(Larus argentatus).Clearly, the most striking effect of certain oils in gulls is the marked reduction in rates of weight gain found after administration of a single 0.2–1 ml oral dose. For example, dosing with one South Lousiana crude (obtained from the American Petroleum Institute in 1976; SLC‐76) reduced weight gain by 40–80%; another SLC, obtained in 1978, had no effect. Gas chromatographic‐mass spectrographic analyses of the oils indicated that SLC‐1978 lacked certain aromatics. Weathering of SLC‐76 over sea water for 36 h did not reduce its ability to inhibit weight gain in gulls. Both findings implicated higher weight aromatics as the active compounds. SLC‐76 was split on an alumina column into aliphatic and aromatic fractions; only the aromatic fraction reduced gull rates of weight gain. Using a Prudhoe Bay crude (as toxic to gulls as SLC‐76), the aromatic fraction was split into two subfractions on Sephadex LH‐20. Analyses showed that one subfraction contained those aromatics with three or less rings and the other contained those with four or more rings. Only the second fraction (high molecular weight aromatics) reduced gull weight gain. These findings clearly show that oil composition is a major determinant of oral toxicity to young seabirds, and that the higher molecular weight aromatics are most effective in reducing

ISSN:0730-7268    

DOI:10.1002/etc.5620010106

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractIn order to efficiently determine safe levels for introduction of toxic chemicals into the environment, regulators need to understand: (1) the environmental chemistry of the chemical, (2) the time‐course of its distribution in the environment, (3) the exposure of key organisms to the chemical, and (4) the effects of the chemical on the exposed biota. It is not practical to determine all of these in field studies for each new chemical; thus, some generalizations must be made based on more limited laboratory determinations. To map from these determinations to a prediction of fate and effects in the field, regulators must implicitly or explicity employ some sort of model.This paper presents one component of a modeling effort directed toward this goal. This model attempts to represent the effects of azinphosmethyl, an example chemical, on an example population of soil/litter invertebrates, based on extensive studies in a field situation and in the laboratory. Exposure of soil/litter‐resident invertebrates is based on the time‐course of toxicant distribution and the activity patterns of the organisms as represented by other models developed in the author's laboratory. Examples of these predicted toxicant distributions and comparable field‐determined values are presented here.A model is proposed here to represent temporally distributed mortality of an invertebrate population caused by repeated toxicant dosing. Detailed toxicological studies on the isopodTrachelipus rathkeihave allowed the best model parameterization, but models for spiders, earthworms, and springtails have also been developed. Model outputs based on laboratory data are compared with field observations of isopod populations. Results indicate some areas in which further model development is r

ISSN:0730-7268    

DOI:10.1002/etc.5620010107

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractEnvironmental fate of TCDD was studied in an aquatic ecosystem, using an outdoor pond which had been dosed initially with 53.7 ppt of14C‐TCDD. The levels of radiocarbon reached an equilibrium in pondweeds after one month, in fish after two months and in the sediment after six months. Using the identical components from the outdoor pond, roughly comparable data were obtained in the laboratory for short‐term distribution of radiocarbon. The largest source of variance and discrepancy between the outdoor and the laboratory data was pondweeds. This material produced the largest shift in biomass due to rapid growth and subsequent massive death, causing a drastic change in distribution of radiocarbon in the second year in the outdoor ecosystem. The amounts of the total TCDD remaining in the pond after 12 and 25 months were 49.7 and 29.4%, respectively. The bulk of metabolites was detected in water and pondwe

ISSN:0730-7268    

DOI:10.1002/etc.5620010108

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

ISSN:0730-7268    

DOI:10.1002/etc.5620010109

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

ISSN:0730-7268    

DOI:10.1002/etc.5620010110

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe systematic scoring of chemicals is a tool to assist in the consistent comparison and ordering of the universe of industrial chemicals. Scoring at an early stage of assessment could identify most of the chemicals that have a high probability for requiring review for possible control or testing. This report describes the results of a three‐day workshop held in Washington, D.C., August 13–15, 1979, to develop a system to select chemicals for preliminary assessments according to their hazard to the environment. The system combines environmental release and distribution potential with mobility and persistence scores in the three environmental media, air, soil, and water. The components of the environmental exposure score are then combined with toxicity by using multipliers (3x, 2x, or 1x) which are assigned on the basis of the concentration at which an adverse effect in environmental species is observed. The system requires minimal information inputs, relies on expert professional judgement and is recognized as an initial phase of selecting candidates for additional assessm

ISSN:0730-7268    

DOI:10.1002/etc.5620010111

出版商:Wiley Periodicals, Inc.    

年代:1982

数据来源: WILEY