ISSN:0730-7268    

DOI:10.1002/etc.5620120701

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThree small ponds in the boreal forest of southern Manitoba were treated with an aerial application of 2.1 kg/ha glyphosate. Two of the ponds had been treated the preceding year with 0.9 kg/ha glyphosate, whereas the third was previously untreated. Foliage samples of plants bordering the ponds were collected immediately after treatment, and water and sediment samples were collected over a period of 265 d after treatment. Samples were analyzed for glyphosate and its first metabolite, aminomethylphosphonic acid (AMPA). We found that glyphosate dissipated rapidly from the surface waters of all ponds (dissipation half‐lives of 3.5‐11.2 d). AMPA residues were detected in water samples during the first 14 d after treatment, suggesting that herbicide degradation was occurring in the water column. However, not all applied herbicide was accountable in residues in the water. Glyphosate and AMPA increased in sediment samples to day 36, suggesting that sediment adsorption was a major sink for the herbicide. Glyphosate dissipation from the water column was biphasic, with a rapid initial phase followed by a slower phase. We hypothesize this was due to herbicide sorption and partitioning between suspended particulate matter and bottom sediments. As was found after the first pond treatment, glyphosate dissipation was slower in chemically alkaline ponds than in a more dilute pond, suggesting that herbicide complexation with ions in solution may be a significant factor affecting the rate of dissipation in standing wa

ISSN:0730-7268    

DOI:10.1002/etc.5620120702

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe degradation of several substituted benzonitriles was examined in anaerobic sediment‐water systems under laboratory conditions. Formation of the corresponding benzoic acids was the main transformation process taking place. The pseudo‐first‐order rate constants of this process were shown to depend on both the chemical structure of the starting compound and the sediment characteristics. The starting compounds were selected with the aim of obtaining a maximum variation in chemical reactivity and physical properties, and the sediments were selected with the aim of assessing several environmental factors influencing the kinetics of transformation. Quantitative structure‐activity relationships were developed for both ortho‐ and meta/para‐substituted nitriles by relating pseudo‐first‐order disappearance rate constants for reductive hydrolysis of 27 aromatic nitriles in anoxic sediment slurries to some readily available molecular descriptors. The best correlations were obtained with the octanol/water partition coefficient of the nitriles and the summation of the inductive constants of the substituents as parameters. The correlations were strongly enhanced by taking into account the fraction of the compounds sorbed to the solid phase. Also it was found that upon correction for sorption, rate constants for reductive hydrolysis of three substituted benzonitriles obtained in six sediment samples did not differ significantly. Thus the obtained relationships may be used to calculate rates of transformation of given aromatic nitriles in given

ISSN:0730-7268    

DOI:10.1002/etc.5620120703

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractEleven selected biological samples representing different ecosystems, trophic levels, and areas mainly in Sweden have been analyzed for 31 halogenated organic compounds or compound groups. The multiresidue analytical method provides a good opportunity to compare the concentrations of the different compounds in the investigated samples. By the use of ratios of these concentrations, comparisons can be done between species and areas. An attempt to describe an environmental distribution profile is demonstrated for some of the compounds using the concentration ratio between these compounds and 2,2′,4,4′,5,5′‐hexachlorobiphenyl (PCB 153). Chlorinated paraffins (CPs) were found in all samples (130‐4,400 ng/g lipid weight [lw]) and in some of them at higher concentrations than the polychlorinated biphenyls (PCBs). The ratio of CP to PCB 153 is higher in the investigated terrestrial species than in the aquatic, which is not the case for the other compounds. Polybrominated diphenyl ethers (PBDEs) were also found in all but one sample (<3‐2,140 ng/g lw). The concentrations were highest in industrialized areas but were also present in samples from background areas. Seven major congeners of PCBs were determined; the sum ranged from 50 to 200,000 ng/g lw in the investigated samples. Three coplanar PCB congeners were also analyzed (0.42‐160 ng/g lw) as well as polychlorinated naphthalenes (PCNs), which were found at levels between 0.038 and 50 ng/g lw. The latter two groups do not seem to biomagnify in the food chain of herring to grey seal to the same extent as the major PCB compounds. Pentachlorobenzene was found in only three of the samples (0.6‐35 ng/g lw), whereas hexachlorobenzene was present in all samples (9‐330 ng/g lw). Among the organochlorine pesticides, total DDTs ranged from 4 to 280,000 ng/g lw and the hexachlorocyclohexanes (HCHs) from<19 to 650. Chlordane (<6‐4,000 ng/g lw), toxaphene (not detected‐5,700), and dieldrin (<11‐340) were also found. None of the analyzed polychlorinated phenols and guaiacols were detected in any of t

ISSN:0730-7268    

DOI:10.1002/etc.5620120704

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractConcentrations of tri‐n‐, di‐n‐, and mono‐n‐butyltin (TBT, DBT, and MBT) were determined for surface sediments collected from 44 sites within Ise Bay, Japan. The concentrations of TBT, DBT, and MBT ranged from not detected (ND) to 0.11, ND to 0.073, and ND to 0.098 μg g−1dry sediment, respectively, excluding one site near a shipyard (TBT concentration 0.54‐1.1 μg g−1dry sediment). The distribution patterns of the three butyltins were similar to each other. The concentration of TBT correlated to the organic carbon (OC) content of the sediment and did not correlate to the sediment particle size. The area with high concentration of butyltin extended from the eastern side of the middle of the bay toward the southwest to Tsu‐Matsuzaka Port. This area had a high organic content area and corresponded to the downwelling zone simulated by a baroclinic three‐dimensional hydrodynamic model. Another area with high butyltin concentrations, near Yokkaichi Port, was also located in the simulated downwelling zone. The area near Nagoya Port, which is in the simulated upwelling zone, had low butyltin concentrations, although the amount of TBT loading in Nagoya Port was estimated to be several times greater than that in Yokkaichi Port. The ratio of TBT to MBT decreased along the direction of surface flow from Yokkaichi Port to the middle of the bay. These results suggested that the amount of the TBT loading could not explain all of the distribution of the TBT concentration in the sediment, and that tidal bay circulations, hydrodynamically up‐ and downwelling, and surface

ISSN:0730-7268    

DOI:10.1002/etc.5620120705

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe validation of the predictive capability of a quantitative structure‐activity relationship (QSAR) is a significant step toward the construction of a reliable model. This point is discussed and illustrated with data for a class of halogenated aliphatic hydrocarbons. For this class of compounds, a QSAR concerning their acute toxicity toward rat was recently published. This QSAR is verified in this study by selecting and testing an external validation set comprising six compounds. The QSAR is also used for predicting the acute toxicity of 38 nontested members of this clas

ISSN:0730-7268    

DOI:10.1002/etc.5620120706

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractAn accurate, rapid, sensitive, and simple method using mercury saturation for quantifying metallothionein (MT) is described. A complex solution (“pseudocytosol”) of enzymatic and non‐enzymatic thiols, including rabbit liver MT‐II, and supernatants from homogenized samples of rainbow trout liver were incubated in the presence of203Hg in 10% trichloroacetic acid Excess Hg was bound to and removed by chicken egg albumin, which denatured on contact with the acidic assay medium. After centrifugation, MT labeled with203Hg remained in the TCA supernatant and was estimated using known stoichiometry for Hg‐MT binding. A dilution series was used to establish that nonspecific metal binding, a common problem with other metal saturation assays, is negligible. Analysis of hepatic MT with high Cu content from rainbow trout demonstrated virtually complete displacement of Cu, Cd, and Zn by Hg. When compared to other metal‐saturation assays developed for vertebrates, this method requires the least number of technical steps, and one‐third or less of total preparatory and an

ISSN:0730-7268    

DOI:10.1002/etc.5620120707

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractWe studied metal accumulation in hepatic and renal tissues of tree swallow (Tachycineta bicolor) nestlings at acidified and nonacid reference lakes in northwestern Ontario Hepatic concentrations of metallothionein (metal binding proteins, MT) in tree swallow nestlings were negatively correlated with pH of the nest‐site lake. Combined concentrations of Cu and Zn in the liver were correlated with liver MT concentrations, but Cd was not. Although no overt signs of metal toxicity were observed in nestlings near acid lakes, our results clearly provided evidence that metals are transferred from acid lakes to birds and that these metals are correlated with increases in hepatic MT productio

ISSN:0730-7268    

DOI:10.1002/etc.5620120708

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractA study was made of the effects of two selected organophosphorus insecticides, phorate and malathion, at concentrations of 10, 50, 100, 200, and 300 μg/g of an agricultural soil on total bacteria populations, fungi, aerobic dinitrogen‐fixing bacteria, denitrifying bacteria, nitrifying bacteria, and nitrogenase activity (acetylene‐reduction assay). The presence of phorate at a concentration of 300 μg/g or malathion at concentrations of 100 to 300 μg/g significantly decreased dinitrogen fixation. Dinitrogen‐fixing bacteria significantly decreased at concentrations of 100 to 300 μg/g of malathion. The presence of 10 to 300 μg/g of malathion significantly reduced the total number of bacteria. However, denitrifying bacteria were significantly increased at concentrations of 50 to 300 μg/g of malathion. Nitrifying bacteria and fungal populations were not affected as a consequence of the addition of the organophosphorus insecticides, showing that these microorganisms can tolerate high amounts of those

ISSN:0730-7268    

DOI:10.1002/etc.5620120709

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractFertilized eggs of ring‐necked pheasants (Phasianus colchicus) were injected into the albumin or yolk with vehicle or graded doses of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) (0.01, 0.1, 1, 10, 100, 1,000, 10,000, or 100,000 pg TCDD/g egg) on day 0 of embryonic development and toxicity was assessed in 1‐d‐old hatchlings and 28‐d‐old chicks. The most sensitive effect of in ovo TCDD exposure was induction of hepatic ethoxyresorufin‐O‐deethylase (EROD) activity in 1‐d‐old hatchlings. The ED50 for this response was 312 pg TCDD/g egg. Embryo mortality was the most sensitive sign of toxicity. The TCDD dose that caused 50% mortality above control (LD50) when injected into the egg albumin or yolk was 1,354 and 2,182 pg TCDD/g egg, respectively. At egg TCDD doses up to and including 1,000 pg TCDD/g egg, no effect was detected in 1‐d‐old hatchlings and 28‐d‐old chicks in body growth, organ weights, carcass morphometrics, incidence of edema, or incidence of histological alterations in the liver, spleen, heart, Bursa of Fabricius, or thymus. Egg TCDD doses as high as 1,000 pg TCDD/g egg also had no effect on cardiac morphometrics or incidence of cardiac malformations in 1‐d‐old hatchlings, or on antibody‐mediated immunity in 28‐d‐old chicks. We conclude that embryo mortality is the most sensitive sign of TCDD toxicity in the ring‐necked pheasant following in ovo exposure. The ring‐necked pheasant embryo is less sensitive than the chicken (Gallus domesticus) embryo and more sensitive than the eastern blu

ISSN:0730-7268    

DOI:10.1002/etc.5620120710

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY