ISSN:0730-7268    

DOI:10.1002/etc.5620131001

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe fate of several halogenated and nonhalogenated heterocyclic compounds in anoxic aquifer slurries was investigated Substrate depletion and methane formation were monitored in serum bottle incubations by HPLC and GC, respectively Pyridine, pyrimidine, thiophene, and furan were not mineralized following an 11‐month incubation, but the corresponding carboxylated or oxygenated compounds were That is,>74% of the theoretically expected amount of methane was recovered from nicotinic acid, uracil, or 2‐furoic acid Chlorinated derivatives, like 2 chloro‐ or 6‐chloronicotinic acid, as well as 4 chloro‐ and 5‐chlorouracil resisted mineralization However, 5‐bromouracil was reductively dehalogenated to stoichiometric amounts of uracil, whereas 2‐chloropyrimidine was metabolized to a more polar unidentified compound that resisted further anaerobic biodegradation Microorganisms acclimated to 5‐bromouracil were unable to transform 4 chloro or 5 chlorouracil These findings illustrate how the structure of heterocyclic contaminants influences their susceptibility

ISSN:0730-7268    

DOI:10.1002/etc.5620131002

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe overall objective of this research is to investigate the desorption reversibility of two PAHs (naphthalene and phenanthrene) from sediment materials Batch adsorption and desorption experiments were designed to minimize the contribution of experimental artifacts The sorbent was sediment obtained from Johnson Ranch (Lula, OK) that contained 92% sand, 6% silt, 2% clay, and 0 27% organic matter Batch adsorption and desorption experiments with radiolabeled chemicals were conducted at various pH levels and ionic strengths, solute concentrations ranging over several orders of magnitude, and equilibrium times up to five months These model pollutants appear to be readily adsorbed by sediment, but a portion of the bound pollutants resists desorption The adsorption is rapid and predictable using published Kocand Kowrelationships From 30 to 50% of the adsorbed amount resists desorption The resistant fraction can be desorbed in water only at rates one to three orders of magnitude slower than previous observations or theories It is hypothesized that some multistep chemical or mechanical effects promote soil aggregation and/or entrapment of pollutants in the soil organic matter during adsorption

ISSN:0730-7268    

DOI:10.1002/etc.5620131003

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractHeterogeneous photocatalysis via TiO2suspensions is effective in anthraquinone 2 sulfonic acid sodium salt (ASS) degradation The presence of oxygen promotes the observed semiconductor powder oxidation of the substrate Degradation of ASS in aerated dispersions of TiO2needed about 24 h at 60°C Added H2O2enhances the degradation rate considerably As the pH increases, the H2O2produced also increases Also, peroxide production was observed as the concentration of TiO2is increased owing to the availability of more surface states for the reaction The Langmuir adsorption isotherm of ASS on TiO2Degussa P‐25 shows that ASS adsorbs readily on the TiO2particles The observed rate for H2O2production decreased as the concentration of isopropanol (hole scavenger) is increased, suggesting an oxidative pathway as the main reaction responsible for H2O2photoproduction The degradation of ASS is a result of indirect action due to light mainly absorbed by TiO2The experiments described here demonstrate the feasibility of dyestuff decomposition via semiconductor powd

ISSN:0730-7268    

DOI:10.1002/etc.5620131004

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe partitioning of14C labelled 2,2,4,4 tetrachlorobiphenyl (TCB) between fish lipids and water was studied in a continuous flow system Fish lipids with high phospholipid content (>20% by weight) accumulated significantly less TCB than did fish lipids with low phospholipid content (<10% by weight) The results suggest that the bioconcentration factor of a hydrophobic compound is species specific depending on lipid composition

ISSN:0730-7268    

DOI:10.1002/etc.5620131005

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractExposure to specific halogenated aromatic hydrocarbons (HAHs), such as 2,3,7,8 tetrachlorodibenzo‐p‐dioxin (TCDD), can produce a wide variety of species‐ and tissue specific toxic and biological effects The presence of HAHs in environmental samples as complex mixtures has made it difficult to predict the biological and toxic potency of these chemicals We have used aspects of the molecular mechanism of action of these chemicals to develop a species‐specific bioassay system for detection of bioactive HAHs in complex mixtures Here we describe construction and utilization of a recombinant expression vector that responds to these HAHs with the induction of an easily measurable gene product, heat‐stable human placental alkaline phosphatase (PAP) This vector contains the PAP gene under TCDD‐inducible control of four dioxin‐responsive DNA enhancer elements HAH inducible expression of PAP from the recombinant vector occurs in a dose‐ and Ah‐receptor‐ (AhR‐) dependent manner Stable transfection of this vector into mouse hepatoma cells has produced a novel cell line in which AhR‐dependent induction of gene expression can easily be measured This transfected cell line can readily be used for detection and relative quantitation of AhR agonists in complex mixtures of environmental and biological samples and for identification and characterizati

ISSN:0730-7268    

DOI:10.1002/etc.5620131006

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractAn experiment was conducted to study the effects of the coplanar non‐ortho‐chlorinated congener 3,3′,4,4′,5‐pentachlorobiphenyl (PCB‐126) in rats exposed during fetal development and postnatal suckling period. Two groups of eight dams were administered by gavage six doses of 10 and 20 μg/kg body weight of PCB‐126 dissolved in corn oil every second day from days 9 to 19 of gestation. The corresponding control rats were treated with corn oil only. The physical development of the offspring was observed. From age 5 to 18 weeks, 12 randomly selected pups from each group were tested daily for visual discrimination with successively more demanding tasks in Skinner boxes. The effects of PCB‐126 on hepatic xenobiotic metabolizing enzyme activities and the concentrations of PCB in the liver and brain were investigated in samples from pups of different age and from their mothers. The litter size, the body weights, and the survival of the exposed sucklings were reduced, and the onset of spontaneous movement and neuromuscular maturation were delayed, whereas the development of reflexes was not affected, as compared to controls The body weight was still reduced in a dose‐related manner up to 18 weeks postpartum. Also, the postpartum body weight of the PCB‐exposed mothers was reduced as compared to controls, but the difference disappeared at weaning. The hepatic enzyme activities of cytochrome P450 1A1 examined by ethoxyresorufinO‐deethylase (EROD) and glutathioneS‐transferase (GST) toward 1‐chloro‐2,4‐dinitrobenzene (CDNB) were increased in both the exposed pups and their mothers, and the relative liver weight was increased in the exposed pups. The behavior training in Skinner boxes did not reveal PCB effects on the learning performance or the activity level Hepatic PCB‐126 residues were detected in samples collected throughout the experiment, whereas no detectable concentration was found in the brain We conclude that exposure of this PCB congener in utero and through lactation showed fetotoxic effects, delayed physical maturation, and induced liver xenobiotic metabolizing enzymes withou

ISSN:0730-7268    

DOI:10.1002/etc.5620131007

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThis study investigates quantitatively the interspecies relationships of the acute toxicity of 684 organic chemicals to the rat, the mouse, and the luminescent marine bacteriumPhotobacterium phosphoreum, commonly known as the Microtox® test The results indicate significant relationships between the Microtox EC50 and rat and mouse LD50 values The goodness of fit increases strongly from the oral to the intraperitoneal to the intravenous route of administration for each of the mouse and rat Standard errors of the estimated rat values range from 0 52 to 0 72 log units of toxicity (after and before outlier removal, respectively) over a toxicity range of 4 6 (intraperitoneal) to 5 0 (oral) log units (mmol/kg body weight) of toxicity For each of the three routes of administration, rat and mouse data are also highly correlated This allows the computation of rat toxicities from mouse data and vice versa with standard errors of the estimates of 0 28 (intraperitoneal) to 0 30 (oral) log unit

ISSN:0730-7268    

DOI:10.1002/etc.5620131008

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractEcotoxicology is concerned with the effects of chemicals on biological systems Identifying components of complex aqueous effluents poses special problems, and can be useless if there is a lack of information on the biological effects of the identified chemicals Toxicity‐based (bioassay directed) sample fractionation can be very useful, but the small amount of fractioned material is a constraint that can be solved by using in vitro tests The RTG 2 in vitro cytotoxicity test has been used to assess (a) the efficacy of a treatment plant in the aeronautics industry and (b) the exposure of fish and molluses cultured in Esteiro Bay to the effluent of a fish processing factory Ecotoxicological assessments could be done without identifying the responsible chemicals The RTG‐2 test was used in combination with concentration/fractionation procedures It proved that the toxicity of the liquid wastes from the aeronautics industry was eliminated by the treatment, and that molluses and fish reared in Esteiro Bay had accumulated toxic chemicals dumped by the fish‐processing factory A combination of the RTG‐2 cytotoxicity test and HPLC proved to give useful information even for chemicals not identified

ISSN:0730-7268    

DOI:10.1002/etc.5620131009

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractWhite phosphorus (P4) has been identified as the cause of mortality for dabbling ducks and swans at an estuanne salt marsh in Alaska Predation of ducks poisoned by P4was monitored to assess the extent and range of predator exposures to P4Avian tissues were analyzed for P4by gas chromatography We observed that both sick and dead dabbling ducks were common prey of bald eagles (Hahaeetus leucocephalus), herring gulls (Larus argentatus), and common ravens (Corvus corax) Frank signs of P4intoxication attracted predators and rendered the ducks easy prey White phosphorus was found in the tis sue remains of ducks that had been preyed upon, thus providing positive evidence that predators were exposed to P4Although P4varied widely among individuals, P4was generally highest in the gizzard contents followed by fatty tissues such as fat depots and the skin White phosphorus was identified in fatty tissues of one eagle and in one herring gull egg, thus providing direct evidence of absorption of P4by predators

ISSN:0730-7268    

DOI:10.1002/etc.5620131010

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY