ISSN:0730-7268    

DOI:10.1002/etc.5620150801

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractFenton's reagent (FR) and the catabolic activity ofRhodococcus corallinusandPseudomonassp. strain D were combined to detoxifys‐triazines in pure solutions and mixed wastes. In solutions containing only atrazine, complete atrazine decomposition was accomplished with 2.69 mM FR. But FR treatment was not complete in a remediation context because stable, potentially carcinogenic chlorinated products accumulated as end products.Rhodococcus corallinusdegraded these products in ≤10 min and produced 47%14CO2from [2,4,6‐14C]atrazine in 7 d. CombiningR. corallinuswithPseudomonassp. strain D increased14CO2production to 73%. When applied to a pesticide rinse water containing atrazine, cyanazine, alachlor, metolachlor, and EPTC, ≥99% of the pesticides were degraded with 12.2 mM FR. Subsequent treatment withR. corallinusandPseudomonassp. strain D degraded all chlorinateds‐triazine intermediates and released 70%14CO2from a [2,4,6‐14C]atrazine tracer in 10 d. Use ofR. corallinusobviated the need for additional chemical pretreatment, e.g., acidification or base hydrolysis, used in previous studies prior to microbial incubations. Thus, this method has potential as an on‐site treatment for pesticid

ISSN:0730-7268    

DOI:10.1002/etc.5620150802

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe aqueous solubility of several low mlecular weight linear, cyclic, and branched permethylsiloxanes was determined at room temperature. A method for preparing molecularly dispersed, colloid‐free saturated aqueous solutions is described. Solubilities, decreasing with increased molecular weights, ranged downward from one part per million to mere parts per trillion. The cyclic oligomers were slightly more soluble than their linear analogues. While the effect of branching was mixed, polar groups such as phenyl and hydroxyl moities sharply increased aqueous solubility. Semilog plots of the solubility/molecular weight yielded linear regressions, the extrapolation of which indicate the absence of any environmentally relevant water solubility (<1 ppt) for the conventional higher molecular weight polydimethylsiloxanes of commerc

ISSN:0730-7268    

DOI:10.1002/etc.5620150803

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractA natural regional petroleum hydrocarbon background has been identified in the subtidal sediments of Prince William Sound that is readily distinguished fromExxon Valdezspill oil by chemical fingerprinting methods. This hydrocarbon background is derived from natural petroleum seeps in the eastern Gulf of Alaska. The Alaska Coastal Current carries fine‐grained sediments and associated hydrocarbons from seep areas to the east into Prince William Sound, where they are deposited on the seafloor. The analysis of age‐dated sediment cores indicates that this process has been going on for the past 160 years, and probably for many thousands of years. In addition, results of a stratified random study of nearshore subtidal sediments conducted in 1990 show that this is a general phenomenon throughout the sound and is significant even in shallow water (3 to 30 m). For example, oleanane, a saturate petroleum biomarker found in Prince William Sound prespill background petroleum and seep sources but not inExxon Valdezpetroleum, is present in subtidal sediment samples from locations throughout the sound. This supports the conclusion that seep areas to the east are major sediment sources for the sound. Moreover, polycyclic aromatic hydrocarbon mixing model calculations show that, althoughExxon Valdezspill‐oil residues are present in nearshore subtidal sediments, they generally form a small increment on the natural background. The recognition of preexisting natural and anthropogenic hydrocarbon sources in a spill area is a fundamentally important component of any natural resource damage asses

ISSN:0730-7268    

DOI:10.1002/etc.5620150804

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractBatch 1‐, 30‐, and 180‐d sorption isotherms were constructed for 1,3‐dichlorobenzene, 2,4‐dichlorophenol, and metolachlor (2‐chloro‐N‐[2‐ethyl‐6‐methylphenyl]‐N‐[2‐methoxy‐1‐methylethyl] acetamide) in aqueous suspension of a fine sandy loam soil (3% organic matter) and a peat soil (93% organic matter) at sorptive concentrations ranging over three to five orders of magnitude. The isotherms were fitted to the Freundlich model,S=KCN, whereSandCare the sorbed and solution‐phase concentrations andKandNare constants. BothKandNwere time‐dependent.Kincreased by as much as 2.7‐fold beyond the 1‐d period.Nwas less than unity in all cases and decreased with increasing sorption. Also, the isotherms were operationally separated into a “fast” fraction (amount sorbed after 1 d) and a “slow” fraction (amount sorbed thereafter).Nswas significantly smaller thanNfin all systems tested. The results show that partitioning in soil organic matter (SOM) is appreciably less ideal for the slow fraction. It is concluded that SOM has both partition and adsorption domains analogous to the dual‐mode sorption model of glassy polymers. The adsorption component is more prominent for the slow fraction, indicating that the adsorption sites are internal to the SOM matrix and unevenly distributed with respect to access by sorbing molecules. Sorption by these natural materials was compared with sorption by polyvinylchloride, a glassy polymer that exhibits dual‐mode sorption. That system gave nonlinear isotherms with anNthat was invariant with time, consistent with its nature as a homogeneous

ISSN:0730-7268    

DOI:10.1002/etc.5620150805

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe grounding of theExxon Valdezon March 24, 1989, released about 41 million L of crude oil into the waters of Prince William Sound, Alaska, USA, and oiled about 16% of the Prince William Sound shoreline to various degrees. Although winter storms, cleanups, and natural biodegradation have removed the majority of the oil on the shorelines, some residual oil still remains trapped in sediments immediately below mussel beds. This oil was protected from wave action by the dense covering of mussels. Field surveys found that mussels in such beds constituted less than 3% of the mussels available for foraging in two areas that had been extensively oiled in 1989. Levels of polycyclic aromatic hydrocarbons (PAHs) in these mussels were also measured. Mean PAH concentrations in mussel tissues ranged between 20 and 4,000 ng/g dry weight and in sediments between 20 and 26,000 ng/g dry weight. Assuming that the species considered most at risk (i.e., harlequin ducks, black oystercatchers, and sea otters) consumed the mussel proportion of their diets exclusively from such beds (at either the median or 95th percentile of mussel tissue PAH concentration), the estimated PAH dosage they would receive was one to three orders of magnitude below doses known to cause sublethal effects in surrogate species. Considering the low frequency of mussel beds with residual oil, the patchy distribution of remaining weathered oil residues, and the relatively low PAH concentrations in the mussels, the risk of quantifiable injury at the level of an individual bird or otter, or at the population level, is minimal. Furthermore, based on a review of the mussel PAH data in Prince William Sound, the risk to wildlife has been minimal since 1990, 1 year after the spill.

ISSN:0730-7268    

DOI:10.1002/etc.5620150806

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe acute and 7‐d subchronic toxicity of methylene blue were determined for fathead minnow larvae using U.S. Environmental Protection Agency methods. The 96‐h lethal concentration (LC50) was 45 and 15 mg/L at 20 and 25°C, respectively. The 7‐d chronic value for survival under laboratory light and low light was the same (2.1 mg/L). However, under laboratory light, larval growth was impaired at lower concentrations (chronic value = 0.6 mg/L) than under low light (chronic value = 2.1 mg/L). To assess prior methylene blue treatment on larval sensitivity, embryos, larvae<24 h old, and embryos followed by larvae were treated with 3 mg/L methylene blue. Cadmium LC50 values were similar between methylene blue‐treated and untreated control groups. When larvae treated with methylene blue as embryos were subchronically exposed to an effluent, survival was similar to that of the untreated group. However, dry weight of the treated larvae was significantly lower. Differences in dry weight between treated and untreated groups were reduced as the age of the larvae at test initiation increased. Treatment of incubating embryos using 3 mg/L methylene blue does not appear to affect larvae sensitivity to cadmium but may affect the growth of larvae used in subchronic

ISSN:0730-7268    

DOI:10.1002/etc.5620150807

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractAllozyme frequencies ofChironomus plumosuswere determined along a gradient of sediment mercury concentrations in a contaminated lake. We examined whether allozyme frequencies could be used to distinguish populations along the gradient or between contaminated and reference sites. No significant correlations were found between allozyme frequencies and contamination, but an overall deficit of heterozygotes (in nine of 13 loci examined) was found at all sites sampled. While toxicant stress could be the cause, a more parsimonious explanation would be sampling over a patchy population structure leading to a heterozygote deficiency (i.e., Wahlund effect). Examination of allozyme frequencies along a transect indicated that the observed deficiency of heterozygote genotypes was due to sampling across some fine‐scale substructuring of the populations. The findings of these studies lend a note of caution regarding the use of allozymes to infer population effects of contaminants or their potential use as biomarkers. Studies must define population structure, naturally occurring variation within and among populations, and relevant ecological factors in conjunction with the presence of xenobiotics and their concentration

ISSN:0730-7268    

DOI:10.1002/etc.5620150808

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe Musselmonitor® (Delta Consult, Kapelle, The Netherlands) is a biomonitor that uses the valve position and the activity of eightDreissena polymorphato monitor the water quality. The normal behavior was studied to evaluate whether eight mussels are sufficient for reliable and reproducible data. The Musselmonitor was placed on a location with strong fluctuations of physical and chemical parameters. The results clearly indicate significant correlations between the valve position and the activity of the mussels and several parameters, such as temperature and concentration of suspended material (represented as turbidity and chlorophyll concentration). The valve position also indicates diurnal and seasonal rhythms in the natural behavior. A new data analyzing system was developed for the Musselmonitor, which takes into account the natural fluctuations in the behavior. The sensitivity of the dynamic data analyzing system was evaluated with copper (20, 40, 50, and 80 μg/L) in dosage experiments and the results were compared with the existing static alarm system. The study revealed that static threshold levels are insensitive and require a lot of experience. The dynamic alarm system works satisfactorily with the Musselmonitor and is very useful for the detection of discontinuities in the normal behavio

ISSN:0730-7268    

DOI:10.1002/etc.5620150809

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe accumulation of heat shock cognate (hsc)/heat shock protein (hsp) 70 was measured in gill and liver from juvenile and adult rainbow trout (Oncorhynchus mykiss) exposed to waterborne metals and/or fed a metal‐contaminated diet. These experiments are part of a larger study in which physiological responses were documented in adult and juvenile rainbow trout after exposure to food‐borne and/or waterborne metals for 21 d. Western blot analyses were used to measure the accumulation of hsp70 and hsc70. Hsc/hsp70 levels were significantly increased in gills of juveniles exposed to metals, in both water and food. The importance of metals in the diet as well as the water was confirmed for the juveniles. Significant increases in hsp/hsc70 could not be demonstrated in the adu

ISSN:0730-7268    

DOI:10.1002/etc.5620150810

出版商:Wiley Periodicals, Inc.    

年代:1996

数据来源: WILEY