ISSN:0730-7268    

DOI:10.1002/etc.5620020301

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

Abstract2,3,7,8‐Tetrachlorodibenzo‐p‐dioxin (TCDD) was metabolized by pure cultures ofNocardiopsisspp. andBacillus megaterium.The degree of metabolism was strongly dependent on the solvent used, with ethyl acetate giving the best results. TCDD metabolism byB. megateriumincreased when the concentration of soybean extract was reduced from 1.6% to 0.8%. Two TCDD‐degrading bacteria were isolated from farm soil that consistently showed a low level of TCDD‐degrading

ISSN:0730-7268    

DOI:10.1002/etc.5620020302

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractUptake and elimination of14C‐labeled terbutryn, fluridone, triphenyl phosphate (TPP),trans‐permethrin, methoxychlor and 2,4,5,2′,4′,5′‐hexachlorobiphenyl (HCBP) byChironomus tentanslarvae were studied in sediment‐water systems. Animals were exposed to three different sediments containing 50 to 500 μg/kg (wet weight) of each chemical, or were held in screened containers in water above the treated sediment for 24 or 96‐h. Elimination of radioactivity was determined over a 48‐h interval. Results were analyzed by use of a one‐compartment kinetic model. Larvae exposed in sand or in water above sand had significantly higher concentrations of each chemical than those exposed in or above river (silty) or pond (silty clay) sediments. Uptake of terbutryn and fluridone, two hydrophilic compounds, was similar (24‐h exposure) to that of methoxychlor and greater than that for TPP,trans‐permethrin or HCBP, due to much greater partitioning of the former compounds into water above each sediment. TPP,trans‐permethrin, methoxychlor and HCBP concentrations were significantly higher in larvae from sediment than in animals held in water above sediment. Uptake rate constants from water for each chemical were much greater than those for sediment, but due to the relatively large sediment‐to‐water ratio (1:5) and the high proportion of chemical in sediment, relative contributions of sediment and water uptake to body burden were similar. Assimilation of each compound by larvae from ingested sediments appeared to be negligible except for TPP and HCBP. Estimates of assimilation of TPP and HCBP in sand‐water systems were much greater than those for sediments wi

ISSN:0730-7268    

DOI:10.1002/etc.5620020303

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractA fluid sample from a shallow aquifer contaminated by coal‐tar wastes was analyzed for organic bases. The sample consisted of a mixture of aqueous and oily‐tar phases. The phases were separated by centrifugation and filtration. Organic bases were isolated from each phase by pH adjustment and solvent extraction. Organic bases in the oily‐tar phase were further purified by neutral‐alumina, micro‐column adsorption chromatography. Separation and identification of the organic bases in each phase were achieved by using capillary gas chromatography‐mass spectrometry‐computer (GC‐MS‐COM) and probe distillation‐high resolution mass spectrometry (PD‐HRMS) techniques. Organic bases present in the aqueous phase included primary aromatic amines (such as aniline, alkylated anilines, and naphthylamines) as well as azaarenes (such as alkylated pyridines, quinolines, acridine, and benzoquinolines). The oily‐tar phase contained acridine, benzacridines, dibenzacridines, and numerous other azaarenes, the elemental compositions of which were determined by PD‐HRMS. Azaarenes in the oily‐tar phase, varying in size from 6 to 12 rings, are reported for the first time. The origin and environmental significance of th

ISSN:0730-7268    

DOI:10.1002/etc.5620020304

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe potential induction of phytoalexin production by stress following exposure to ozone, sulfur dioxide and several herbicides was evaluated in bean (Phaseolus vulgarisL.) cultivars and lines varying in sensitivity to ozone injury. The isoflavonoids, coumestrol and several other coumestans were extracted from leaf tissue after various periods of exposure to ozone, sulfur dioxide or application of various herbicides. Elicitation of isoflavonoid production varied with lines and cultivars, but generally increased with increased plant injury caused by ozone, sulfur dioxide or herbicide.

ISSN:0730-7268    

DOI:10.1002/etc.5620020305

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractA novel method has been developed for the qualitative and quantitative characterization of (a) waterborne organosilicon substances, which are present as low‐molecular‐weight silanols (such as silicone hydrolysis products), and (b) higher‐molecular‐weight materials (e.g., silicones), which can be caused to undergo hydrolysis to yield such low‐molecular‐weight silanol‐functional materials. This method is capable of good to excellent accuracy and precision in the parts per million range and, with suitable precautions, has the potential for extension to determinations in the low parts per billion range. Although particularly valuable for the analysis of water‐soluble species, this method can also be adapted to yield useful information concerning water‐insoluble organosilicon materials present in aqueous systems, such as colloidal suspensions, surface films, or sedimentary slurries. Because of its inherent sensitivity and selectivity, this method constitutes a valuable tool for measuring and characterizing the silicone content of industrial and municipal waste waters, surface and ground waters, foods and biological tissues, etc. The determination of water‐soluble organosilanol species is accomplished by the acid‐catalyzed trimethylsilylation of the silanol functionality with hexamethyldisiloxane (HMDS) followed by gas‐liquid chromatographic assay of the resulting HMDS extract. Water‐insoluble components are determined by subjecting the sample to acidic predigestion before the addition of the HMDS‐derivatizing and extracting reagent. The possibility of dimethyl‐ or monomethyl‐silicon artifacts arising from inadvertent trace cleavage of methyl groups from the HMDS can be determined and/or precluded by the use of hexaethyldisiloxane or p

ISSN:0730-7268    

DOI:10.1002/etc.5620020306

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractA method has been developed for the determination of pAg in natural water samples using a direct potentiometric measurement technique. Calibration standards have been prepared, and linearity of the technique has been demonstrated for the pAg range of 2 to 11, with Nernstian response. The method has been applied to samples of several natural waters in the United States and the results are tabulated. The measured pAg values of natural waters were within the range of 8.8 to 12.0, corresponding to silver ion activities of 0.0001 to 0.2 μg/L

ISSN:0730-7268    

DOI:10.1002/etc.5620020307

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractA pharmacokinetic model was used to predict the acute toxicity of weak electrolytes to fish as a function of pH. For weak acids, the model predicted that the toxic concentration‐pH profile was shifted to the right of the ionized fraction‐pH profile. The relative rates of uptake of ionized and nonionized species can be calculated using toxic concentration‐pH

ISSN:0730-7268    

DOI:10.1002/etc.5620020308

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractTwo fish and seven invertebrate freshwater species were exposed to diflubenzuron (Dimilin®) in acute and chronic laboratory tests. No effects on newly hatched and juvenile fathead minnows or juvenile guppies were seen at or below 36 μg/L, the highest concentration tested. An early‐life‐stage test (30‐d) with fathead minnows showed no effect at or below 36 μg/L. No effects on survival, growth or reproduction were observed with two snail species,Juga pliciferaandPhysaspp., at or below 36 μg/L. Adult emergence of the caddis flyClistoronia magnificawas inhibited at 0.1 μg/L.Daphnia magnawere killed at 2.0 μg/L.Hyalella aztecamortality was significant at 2.0 μg/L. Molting and survival of the midgeTanytarsus dissimiliswere affected at 4.9 μg/L. Molting and survival of the midgeCricotopusspp. were affected at 4.9 μg/L, and adult emergence did not occ

ISSN:0730-7268    

DOI:10.1002/etc.5620020309

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY

摘要:

AbstractEarly life‐stage toxicity tests (continuous exposure from embryonic stage to 3 weeks or more into the exogenous feeding stage) with North American marine fishes have been conducted almost exclusively with cyprinodontids. In this report, we present methods for testing a representative of another family, Atherinidae. Embryos of the tidewater silversideMenidia peninsulae(Goode and Bean) were obtained by a laboratory spawning procedure that required lighting and tidal (current) stimuli. A 28‐d toxicity test with chlorine‐produced oxidants (CPO) began with stage 21 and 22 embryos (approximately 36 h old). Average measured CPO concentrations in exposure water were nondetectable (<0.01 mg/L) in the control and in the two lowest exposure concentrations, and 0.01, 0.04 and 0.21 mg/L. Survival of embryos to hatching averaged 99%, with no significant difference among treatments. Although no fish survived exposure to 0.21 mg CPO/L, survival was ≥ 88% in the control and the four other CPO treatments. Average wet weights of individual fish ranged from 11.7 mg in 0.04 mg/L to 13.2 mg in 0.01 mg/L, with no significant difference among tre

ISSN:0730-7268    

DOI:10.1002/etc.5620020310

出版商:Wiley Periodicals, Inc.    

年代:1983

数据来源: WILEY