ISSN:0730-7268    

DOI:10.1002/etc.5620040501

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe biodegradation of nitrilotriacetic acid (NTA) was examined in three estuarine ecosystems, one of which had been exposed previously to the chemical. Biodegradation was measured as the conversion of radiolabeled NTA to14CO2,14C‐labeled cells and the amount of label remaining in solution. The relatively unpolluted Newport River estuary system in North Carolina metabolized NTA slowly, with no apparent increase in rate over time. Jamaica Bay in New York showed an adaptation response, with approximately 50 d required for the onset of relatively rapid rates of biodegradation. The Fraser River estuary in Canada, exposed to NTA for more than 10 years, showed rapid degradation with no lag period at a concentration of 10 μg/L. At 100 and 2,000 μg/L, short lag periods (2 to 4 d) were observed before rapid degradation rates were achieved. Measurements of NTA‐degraders indicated that the Fraser River estuary contained 650/ml versus fewer than 10 in the Newport River and Jamaica Bay communities. The results demonstrate that NTA can be degraded by estuarine microorganisms. Estuarine bacteria will adapt to the presence of NTA in the environment and, after adaptation, can respond to increased levels of the compound after relatively short lag pe

ISSN:0730-7268    

DOI:10.1002/etc.5620040502

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractQuantitative structure‐activity relationships (QSARs) predict bioconcentration and acute toxicity to fish of chemicals causing narcosis on the basis of hydrophobicity, as measured by the octanol/water partition coefficient (Kow). Since the development of water quality objectives to protect fish is limited by the availability of suitable chronic toxicity data, we applied the QSAR concept to published and unpublished data to determine (a) whether chronic toxicity could be related toKowand (b) whether application factors are constant, i.e., whether QSARs for acute and chronic toxicity are parallel. Our conclusions are as follows: (1) A QSAR, based on hydrophobicity (logKow), appears to exist for the chronic toxicity of organic chemicals inducing acute toxicity by narcosis. Although not definitive, this QSAR was not parallel to that for acute toxicity and does not appear to support the concept of constant application factors. (2) LogKowhas a major effect on the rate of net bioconcentration of certain organic chemicals; therefore, the relationship of toxicity to logKowmay not be linear if exposure times are fixed, as very different amounts of toxicants will be taken up over a fixed time period. (3) As a result of the effect of logKowon bioconcentration rates, many toxicity tests of relatively short, fixed duration may underestimate toxicity of some hydrophobic organic compounds, especially those exhibiting high logKowvalues. Hence, water quality objectives developed directly from this data, without appropriate compensation, may not be restrictive enough. (4) To increase the accuracy, comparability and applicability of aquatic bioassay test results, especially for compounds of widely differing hydrophobicity, standard tests should be redesigned. For example, it may be more accurate if the exposure or dosage for the test organism is expressed as a summation of the periodically calculated product of body toxicant level and time up to predetermined summation value

ISSN:0730-7268    

DOI:10.1002/etc.5620040503

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe binding of benzidine (4,4′‐diaminobiphenyl), α‐naphthylamine (1‐aminonaphthalene) andp‐toluidine (4‐methylaniline) by three soils was studied by incubating soils amended with the aromatic amines and then sequentially extracting them with 60:40 (v/v) ethylacetate: methanol (EtAc: MeOH), ammonium acetate (NH4OAc) and sodium hydroxide (NaOH) as a function of time. Essentially all of the added α‐naphthylamine andp‐toluidine was extracted initially with EtAc: MeOH and NH4OAc, whereas only 21% of added benzidine was extracted by these reagents. After 24 h, a significant decrease was found for amines extractable with EtAc: MeOH and NH4OAc. During 63 to 84 d after incubation, a gradual increase in the proportion of amine recovered by NaOH extraction was found. Fractionation of the NaOH extract into humic and fulvic acids indicated that benzidine and α‐naphthylamine were primarily associated with the humic acid fraction, whereasp‐toluidine was in the fulvic acid fraction. Simultaneous measurement of14CO2evolved showed that the average decomposition rate was 2, 12 and 15% for benzidine, α‐naphthylamine andp‐toluidine, respectively. Results indicate that binding of benzidine, α‐naphthylamine andp‐toluidine to soils involves both rapid, reversible equilibrium with inorganic and organic components of soil and nucleophilic addition to the phenolic components of humus. These retention mechanisms may explain why benzidine, α‐naphthylamine andp‐to

ISSN:0730-7268    

DOI:10.1002/etc.5620040504

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractAryl hydrocarbon hydroxylase (AHH) levels were measured in the livers of herring gull (Larus argentatus) embryos to determine if monooxygenase activity in this species could be used as a “bioeffects” monitor of environmental contamination. Herring gull eggs were collected in 1981 from five locations on the Great Lakes Basin and from one clean colony on the Atlantic coast. Microsomal protein determinations and AHH assays were conducted on livers from the embryos at 20 and 25 d of incubation. Organochlorines (DDE, DDT, tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, heptachlor epoxide, chlordane, dieldrin, mirex, photomirex, polychlorinated biphenyls and 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin) were also measured in egg homogenates from each colony. The 25‐d embryos were found to be the most suitable for AHH analysis, since they had a higher baseline level and a greater response than did the 20‐d embryos. Specimens from two of the Great Lakes colonies had significantly higher AHH activities than was found for the Atlantic coast colony. These levels of AHH activity closely paralleled the concentrations of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin present in eggs gathered from the colonies in 1980. Further work regarding monooxygenase levels in herring gull e

ISSN:0730-7268    

DOI:10.1002/etc.5620040505

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe artifactual generation ofN‐nitrosamines during analytical procedures and the presence of volatile nitrosamines in human feces were reinvestigated. Various solvents and desiccants — sodium sulfate, magnesium sulfate and calcium chloride—were highly catalytic in nature and induced markedN‐nitrosation of secondary amines. During theN‐nitrosamine analysis, high levels of volatile nitrosamines, detected in the original method using dichloromethane as the extracting solvent and sodium sulfate as the desiccant, were artifactually generated. Few volatile nitrosamines were detected by the new method, in which extraction by ether and dehydration by potassium carbonate were carried out. The recovery values of volatile nitrosamines by the new method were similar to the values obtained by the original method. Therefore, it is concluded that volatile nitrosamines do not seem likely to be present in significant amounts in hu

ISSN:0730-7268    

DOI:10.1002/etc.5620040506

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe discharge of effluents containing creosote and pentachlorophenol into two unlined surface impoundments at a wood‐treatment facility in Pensacola, Florida, resulted in contamination of the underlying sand and gravel aquifer. These wastes contained significant amounts of chlorinated dioxins, such as isomers of hexa‐ and heptachlorodibenzo‐p‐dioxins and octachlorodibenzo‐p‐dioxin, probably derived from commercial pentachlorophenol. Geochemical investigations of pond sludge, groundwater and porous media from the unsaturated and saturated zones indicated that these geologic materials were contaminated by chlorinated dioxins. The fate and movement of these compounds in the subsurface environment were studied using the technique of GC‐MS‐MS. Chlorinated dioxins migrated both vertically and horizontally in the subsurface and were present at considerable distances from the source of contamination. Concentrations of chlorinated dioxins in groundwater were several orders of magnitude lower than in porous media from the unsaturated and saturated zones. Ratios of the various isomers remained relatively constant in highly contaminated areas. However, in less contaminated areas, isomer ratios changed dramatically; at certain locations, one hexachlorodibenzo‐p‐dioxin isomer predominated. The environmental significance of these com

ISSN:0730-7268    

DOI:10.1002/etc.5620040507

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractAldicarb was applied to potato plants in two locations in Wisconsin to determine the effects of application procedures and irrigation on degradation and movement of aldicarb residues, plant uptake, insect control and crop yield. Two application procedures (3.36 kg. AI/ha applied in the furrows at planting and 2.24 kg AI/ha applied as a top‐dress application consisting of a surface‐applied band covered with soil at plant emergence) and two irrigation regimens (medium water use based on evapotranspiration and heavy water use based on evapotranspiration plus 60%) were tested. The emergence application was effective in reducing the downward movement of aldicarb residues without significantly affecting performance as measured by insecticidal efficacy, crop residues and yield. Excess irrigation increased downward movement of aldicarb residues in soil, diminished foliar residues and resulted in decreased insect control and crop yield. Differences in soil characteristics, primarily in water‐holding capacity, were important in reducing downward movement of aldicarb in

ISSN:0730-7268    

DOI:10.1002/etc.5620040508

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractWater solubilities, octanol/water partition coefficients and vapor pressures were measured for a variety of commercial phthalate esters, several of which were mixtures. The results provide insight into the applicability of the procedures, which were developed for pure compounds, to more complex industrial products and formulations.

ISSN:0730-7268    

DOI:10.1002/etc.5620040509

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe fate of14C‐labeledt‐butylphenyldiphenyl phosphate (tBPDP), 2‐ethylhexyl diphenyl phosphate (EHDP) and tri(m‐cresyl) phosphate (mTCP) was studied for up to 360 d following addition of each compound to artificial ponds (5 m3volume) to give initial water concentrations of about 50 μg/L. Concentrations of each phosphate ester decreased rapidly, with half‐lives of about 0.5 d for each compound. Concentrations of intact esters in bottom sediments decreased more slowly, with half‐lives of 39 d for tBPDP and mTCP and 79 d for EHDP. A series of unidentified14C‐labeled nonpolar oxidation products, as well as diaryl phosphates, was isolated by TLC analysis of extracts of water and sediment. Concentrations of 197 ng/m3tBPDP and 32 ng/m3EHDP were detected in air (5 cm height) above the ponds during the first 18 h after the addition of the esters to the water. Volatilization losses during the experiment were estimated to represent less than 10% of the amounts added to the water initially. Maximum concentrations in fathead minnows (Pimephales promelas), ranging from 7.3 μg/g for mTCP to 10 μg/g for tBPDP, were observed 8 h after application. Chironomid larvae collected from bottom sediments accumulated concentrations that were 11‐ to 37‐fold greater than levels of each compound present in sediment. After 360 d, most of the remaining14C was present in bottom sediment, representing 24 to 30% of the amo

ISSN:0730-7268    

DOI:10.1002/etc.5620040510

出版商:Wiley Periodicals, Inc.    

年代:1985

数据来源: WILEY