ISSN:0730-7268    

DOI:10.1002/etc.5620120901

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractEmphasis in environmental protection is shifting from primary attention to human health to a more balanced consideration of human and ecological health. This shift provides opportunities and challenges to the scientific community. For example, success depends on development of operational definitions of ecological health and programs to measure that health. Ecological health is inextricably tied to concepts such as biological diversity and biological integrity. Water chemistry and toxicity testing have dominated water‐quality programs for decades. Success in protecting the ecological health of water resources depends on our ability to supplement those methods with ecologically robust approaches. Existing definitions and approaches for measuring the quality of water resources provide a template to guide development of procedures to assess ecological health. Critical components of successful monitoring programs should include evaluations relative to regional expectations, use multimetric indexes that reflect the multivariate nature of biological systems, and include index components (metrics) that evaluate conditions from individual, population, assemblage, and landscape perspective

ISSN:0730-7268    

DOI:10.1002/etc.5620120902

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractBecause people wish to preserve their health and do something equivalent for ecosystems, the metaphor of ecosystem health springs to mind. This paper presents the argument that it is a mistake for environmental scientists to treat this metaphor as reality. First, the metaphor fails because it misrepresents both ecology and health science. Ecosystems are not organisms, so they do not behave like organisms and do not have properties of organisms such as health. Also, health is not an operational concept for physicians or health risk assessors because they must predict, diagnose, and treat specific states called diseases or injuries; they do not calculate indexes of health. Second, attempts to operationally define ecosystem health result in the creation of indexes of heterogeneous variables. Such indexes have no meaning; they cannot be predicted, so they are not applicable to most regulatory problems; they have no diagnostic power; effects on one component are eclipsed by responses of other components; and the reason for a high or low index value is unknown. Their only virtue is that they reduce the complex array of ecosystem responses to various disturbances to one number with a reassuring name. A better alternative is to assess the real array of ecosystem responses so that causes can be diagnosed, future states can be predicted, and benefits of treatments can be compared.

ISSN:0730-7268    

DOI:10.1002/etc.5620120903

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractWe assessed a series of chemical and biological variables for their abilities and cost effectiveness in determining recovery rates in streams. Using data gathered at the experimental streams of the Monticello Ecological Research Station, several water‐quality variables (DO, pH, nutrients), macroinvertebrate densities, macrophyte biomass, and periphyton biomass, and several ecosystem‐level variables (e.g., primary production) were compiled and analyzed. Water‐quality variables were relatively inexpensive to measure, and many would be relatively easily collected for assessing recovery rates; however, their overall explanatory power for determining recovery of streams, especially biological phenomena, was limited. Several biological variables, including gross primary production, respiration, leaf litter decomposition rates, macroinvertebrate richness, and Collembola density, could be measured reasonably well and required relatively small sample sizes (n<10) for detecting recovery rates. However, collection of most of these variables was more costly than collection of chemical water‐quality variables. The ultimate determination of which variables to measure in assessing recovery in a given ecosystem will need to be based on the disturbances being examined, the importance of the variables to stream health, and the available monetary resources. Generally, comprehensive analyses of recovery rates for a variety of aquatic systems will greatly increase our ability to develop a framework for predicting recovery rates and ultimately improving the quality of the envi

ISSN:0730-7268    

DOI:10.1002/etc.5620120904

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractEight sediment cores were taken from Lake Ketelmeer, a sedimentation area of the Rhine River, located in the central part of The Netherlands. Priority pollutants (eight metals, six planar and mono‐ortho polychlorinated biphenyls, seven polychlorinated dibenzo‐p‐dioxins, 10 polychlo‐rinated dibenzofurans, and eight polycyclic aromatic hydrocarbons) were determined in all or in a selected number of cores. Present‐day and historical levels of pollutants since the late 1930s were established through the use of radionuclide time tracers (137Cs,134Cs) and area‐specific geological time markers. Postdepositional redistribution of pollutants and possible transformations were evaluated by analyzing sediment top‐layer samples that were taken in 1972. Disappearance in the anaerobic sediment was observed for several chlorinated biphenyls, dioxins, and furans, Disappearance of the chlorinated compounds may be caused by microbial dechlorination reactions in the anaerobic lake sediment. For the persistent metals and polycyclic aromatic hydrocarbons, as well as for the somewhat changed concentrations of chlorinated aromatics, trends in the concentration profiles during the last five decades are described. Rather low concentrations of almost all studied chlorinated compounds were observed in the early 1940s. These low levels were in contrast to the metal and PAH concentrations, which were already high in the late 1930s and were lowered during the second world war. For all studied compounds, maximum concentrations were found between 1955 and 1975. Cadmium and nickel levels remained high until 1980. The highly toxic 2,3,7,8‐tetrachlo‐rodibenzo‐p‐dioxin reached concentrations up to 400 ng/kg in the mid‐1960s. Recently deposited sediments showed lower pollutant levels. The levels of lead, arsenic, and all studied PAHs were the lowest observed i

ISSN:0730-7268    

DOI:10.1002/etc.5620120905

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractDeposition fluxes have been estimated from concentrations of 12 polynuclear aromatic hydrocarbons (PAHs) and six heavy metals measured in sediment cores from Esthwaite Water, a rural English lake. Atmospheric deposition is a major source of PAHs and heavy metals (Cd, Cu, Pb, and Zn) to the lake, so trends in the core may indicate the long‐term record of changes in the atmospheric loading of these pollutants. The cores were dated radiometrically and pollutant trends studied since about 1820. PAH fluxes began to increase from stable background levels around the turn of the century (4.1 μg ΣPAH per gram dry weight, 287 ng ΣPAH per centimeter squared per year), rising to maximum inputs between 1950 and 1970 (42.0 μg/g, 2,954 ng/cm2per year). The deposition flux of PAHs has decreased steadily since then and is now less than half the maximum (18.0 μg/g, 1,238 ng/cm2per year). In recent sediments (1900‐1970), the relative proportions of individual PAHs making up the ΣPAH burden have remained virtually unchanged, with fluoranthene, pyrene, and benzo[ghi]perylene the most abundant compounds. However, perylene, a biogenically produced PAH, dominates the mixture in the sediments older than 1890. Cadmium, Cu, Ni, Pb, and Zn concentrations in the Esthwaite sediments broadly follow the same temporal trends as the PAHs, with varying peak inputs between 1925 and 1975. Concentrations in the modern (surface) sediments are now lower than in recent decades, with ΣPAH, Cd, and Pb showing the greatest reduction. However, fluxes of these contaminants to surface sediments are still greater than those deposited b

ISSN:0730-7268    

DOI:10.1002/etc.5620120906

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractSediments from two depositional zones of the North Sea (the Wadden Sea and Oyster Grounds) and from the estuaries of the rivers Rhine, Meuse, Scheldt, Ems, and Humber were analyzed for polychlorinated dibenzofurans (PCDFs) and dibenzo‐p‐dioxins (PCDDs) using a congener‐specific procedure. A simple grain‐size correction procedure was utilized for the comparison of PCDF and PCDD concentrations in sediments from different origin. This procedure, which applies wet sieving of fresh sediment and isolating and analyzing the<63‐μm grain‐size fraction, was found to be appropriate for comparing levels of PCDFs and PCDDs in different estuarine and coastal sediments. PCDFs were more widely encountered than PCDDs in all sediments, except for the Ems‐Dollard and the Humber estuary. The highest concentrations were found in the outflow sediments of the rivers Rhine and Humber. Concentrations up to 2,980 ng/kg PCDFs, principally 1,2,3,4,6,7,8‐HpCDF and OCDF, and up to 1,760 ng/kg PCDDs, principally OCDD, were determined in the River Rhine sediments. Principal component analysis was used to visualize the compositional changes of PCDD and PCDF profiles in the sediments. Two‐dimensional projections based on sample scores from the principal component models showed a marked influence of the River Rhine on the presence of these compounds in the western Wadden Sea and the Oyster Grounds. Based on a chemo‐metric evaluation of chromatographic profiles of these coastal, estuarine and related freshwater sediments, we have deduced that these compounds originate primarily from industrial operation discharges, related to the production of chloroaliphatic compounds and the chloralkali industry along the River Rhine. The atmospheric deposition of combustion‐generated PCDDs and PCDFs appeared significant only for remo

ISSN:0730-7268    

DOI:10.1002/etc.5620120907

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe behavior of LAS (linear alkylbenzene sulfonate) in different environmental compartments was studied through wastewater treatment process steps in sewage treatment plants of Alicante and Benidorm (activated sludge type) as well as in Guardamar (lagoons). The fate of LAS, using a specific HPLC method, was monitored during treatment sludge compostage and soil amendment operations. Finally, the marine sediments close to a submarine wastewater sewer outfall were analyzed. The results show significant differences between distribution of LAS homologs in water and solids (sludges, sediments, and soils), as compared to the original distribution in detergent formulations, yielding a lower LAS average molecular weight in water samples. The change observed in the homolog distribution of LAS implies a reduction in the toxicity toDaphnia, because a lower average molecular weight of LAS is less toxic.

ISSN:0730-7268    

DOI:10.1002/etc.5620120908

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractSpecific rate constants associated with defined molecular paths of carbon‐halogen bond cleavage from a variety of alkyl halide substrates by six soil organisms are presented. Five aerobes (three pseudomonads, one methylotroph, and one flavobacterium) and one anaerobe (a methano‐gen) are compared. The rate constants were obtained with resting cells in phosphate buffer at pH 7.4 in the absence of nutrients or other substances. The observed general rate law is d(X−)/dt=k(RX)(organisms), wherein X−= halide ion, RX = alkyl halide, and (organisms) = number of organisms per liter. At concentrations of substrates ≥10−3M, the rate may diminish or cease due to the toxicity of the substrate. At high cell densities ≥0.1 g/ml wet weight, the rates may saturate. This is attributed to a packing phenomenon of the cells. There is no simple correlation of rates with the chemical structure of the substrates when the conversions are grouped by reaction type; however, the order of reductive hydrogenolysis roughly follows the carbon‐halogen bond dissociation energies. Several factors may contribute to a modulation of the rates observed with defined enzymatic active site models in homogeneous solution. These factors are briefly discussed. The aerobes exhibited a greater chemical diversity than the anaerobe in transforming these substances, and they react with much greater speed. In these biotransformations reductive processes occur more often than substitutions or oxidations. A surprising result was that the aerobes can reductively dehaloge‐nate more rapidly th

ISSN:0730-7268    

DOI:10.1002/etc.5620120909

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe purpose of this investigation was to develop a specific immunological probe to rainbow trout cytochrome P450 1A1 (CYP1A1). Three oligopeptides corresponding to different regions of trout CYP1A1 (amino acids 162‐181, 250‐267, 277‐294) were coupled to keyhole limpet hemo‐cyanin (KLH) using two different methods. All three peptides were coupled to KLH through side‐chain amine and carboxyl groups of the peptide; peptides 162‐181 and 277‐294 were also coupled to KLH through the sulfhydryl group of a cysteine residue of each peptide. These five peptide‐KLH conjugates were used to immunize rabbits. Antibody production and specificity were monitored by Western immunoblot analyses. All of the antipeptide antisera showed strong reactivity with the corresponding peptides used to generate the antisera. Four of these five antisera, however, did not react with the trout CYP1A1 protein. In contrast, the antiserum directed against peptide 277‐294 (which was coupled to KLH through a sulfhydryl linkage) reacted strongly and specifically with the trout CYP1A1 protein. These antipeptide antibodies had a high affinity for CYP1A1 in liver microsomes from rainbow trout that had been exposed to β‐naphthoflavone G3‐NF), a known CYP1A1 inducer in trout. Microsomal proteins from control trout were not recognized by the antipeptide antibodies. Preimmune serum from the rabbits did not recognize any proteins in control or β‐NF‐treated trout. These findings demonstrate that antipeptide antibodies directed against peptide 277‐294 can be easily produced in large quantities and used in research or biomonitoring studies for the detecti

ISSN:0730-7268    

DOI:10.1002/etc.5620120910

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY