ISSN:0730-7268    

DOI:10.1002/etc.5620091101

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractSamples of new and weathered utility lumber pressure‐treated with chromated copper arsenate (CCA) were tested for leaching of copper, chromium and arsenic by submersion in leaching baths of various pH levels. Accumulation of metals was monitored in leachate at pH 3.5, 4.5, 5.5, 7.0 and 8.5 over a period of 40 d by atomic absorption spectroscopy. Copper, chromium and arsenic were found in the leachate of both new and weathered wood with significantly higher levels of all metals occurring at acidic pH levels. Up to 100% of CCA treatment metals were found to have leached at pH 3.5, whereas a maximum of 9% of metals leached at pH 8.5. Metal leaching was found to be higher in citric acid than in dilute sulfuric acid solutions. Leaching of copper, chromium and arsenic was not proportional to the amount of metal present before leachin

ISSN:0730-7268    

DOI:10.1002/etc.5620091102

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractA strategy for systematic analysis and priority ranking of chemical compounds was applied to a class of 58 saturated halogenated aliphatics. By means of a fractional factorial design, a training set consisting of 10 compounds was selected. The training set compounds were subjected to biological testing and their acute oral toxicity to rat and highest nonlethal dose to mouse were determined. Based on the selected training set, two multivariate quantitative structure‐activity relationships (QSARs) were developed. It was concluded that both end points needed a multivariate structural description to be modelled. The derived QSARs were used to predict the potential hazards of the remaining compounds in the clas

ISSN:0730-7268    

DOI:10.1002/etc.5620091103

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractA new, rapid test is reported for the toxicity screening of sediments using inhibition ofPhotobacterium phosphoreum.The bacteria are placed in direct contact with the sediment and the change in luminescence of thePhotobacteriumis used to determine the toxicity of the sediment relative to a control site. This sediment‐contact bioassay appears to be more sensitive to hydrophobic contaminants such as a polychlorinated biphenyl than the standard sediment elutriate test with Microtox® bioass

ISSN:0730-7268    

DOI:10.1002/etc.5620091104

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe environmental fate of nitroguanidine (NQ) in surface waters is dominated by photolysis with surface half‐lives at 40°N ranging from 0.6 d in summer to 2.3 d in winter. The environmental quantum yield is 0.01. The NQ is initially photolyzed to nitrite and hydroxyguanidine; nitrite is photochemically converted to nitrate and hydroxyguanidine undergoes sensitized photolysis to unknown products. The photooxidation of nitrite is assisted by organic material in a process not involving H2O2or singlet oxygen. Nitroguanidine biotransforms cometabolically; in the absence of extra organic nutrients the second‐order rate constant was (3.8 ± 0.9) × 10−10ml cell−1h−1. Half‐life estimates for aerobic, aquatic biotransformation range from 1 to 100 d. Cyanamide appears to be an end product of NQ use and no intermediate biotransformation products were observed. Nitroguanidine is expected to move readily through soils (soil sorption coefficientKp<0.1); however, anaerobic biotransformation occurs readily in soil, with an estimated half‐life of 4 d.Other fate parameters measured at 25°C are a water solubility of 2,600 ± 100 ppm, octanol/water partition coefficient of 0.148 ± 0.001 (dimensionless), Henry's constant of<7 × 10−6(dimension‐less), base hydrolysis constant of (3 ± 1) × 10−4M−1S−1, neutral hydrolysis constant ≤ 2 × 10−8s−1, and biouptake constants of 110 g dry cells/g water forAnabena flos‐aquaeand 150 g dry c

ISSN:0730-7268    

DOI:10.1002/etc.5620091105

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractBiodegradation is an important removal mechanism for consumer product chemicals released in large volumes to aquatic and terrestrial environments. It results in a decrease in the mass or load of chemicals present in the environment and is key in preventing accumulation and persistence of chemicals. Although biodegradation is an important process in minimizing potentially adverse impacts on environmental systems, it has not been traditionally considered quantitatively in environmental assessments. Efforts to use such data have principally focused on either wholly qualitative evaluations of a material's biodegradation properties (e.g., “fast” or “slow”), or rigorous quantitative models to predict exposure concentrations in particular settings. This paper outlines an alternative approach which provides a semi‐quantitative analysis combining biodegradation rate data with an assessment of environmental exposure. The approach is a generic one that relates biodegradation half‐lives to rates of transport and residence times in specific environmental compartments (e.g., agricultural soil, rivers). It establishes the kinetic criteria needed to make biodegradation a “practically significant” removal mechanism in a given environmental compartment. It is broadly applicable to chemicals which exhibit pseudo first order biodegradation kinetics at realistic environmental

ISSN:0730-7268    

DOI:10.1002/etc.5620091106

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effects of lead (Pb2+) and various pesticides on δ‐aminolevulinic acid dehydratase (ALA‐d) in avian blood, liver and kidney were studied. In blood, virtually all of the ALA‐d activity was localized in the cellular fraction. Complete inhibition of RBC ALA‐d occurred at an in vitro Pb2+concentration of ∼10 μmol/g protein, with an IC50 of ∼0.9 μmol/g protein. Pesticides (carbaryl, carbofuran, chlorpyrifos, diazinon, dieldrin, fenitrothion, hexachlorobenzene) added to blood samples up to 10 mM in vitro had no inhibitory effect on ALA‐d, nor did the presence of pesticides greatly modify the response of ALA‐d to inhibition by increasing concentrations of Pb2+. Recovery of Pb‐inactivated RBC ALA‐d activity was accomplished by treatment of blood hemolysates with Zn2+and an SH‐reducing agent such as dithiothreitol (DTT). A combination of Zn2+(4 mM) and DTT (120 mM) was required to achieve complete recovery of Pb‐inhibited enzyme activity. Normal avian ALA‐d activity was greatest in blood, followed by liver, then kidney. Unlike blood hemolysates, liver and kidney homogenates contained a fraction of ALA‐d activity which was very resistant to inhibition by in vitro Pb2+. In vivo, hepatic ALA‐d was unaffected by Pb exposure (2.5 μg Pb2+/g body weight injected intraperitoneally), but renal ALA‐d was decreased as a result of greater deposition of Pb in kidney than in liver. Inhibition of ALA‐d in avian blood, particularly when expressed as a ratio of fully restored:nonrestored activity (activity ratio), is a highly specific, sensitive indicator of Pb exposure, deposition and corresponding enzyme inhib

ISSN:0730-7268    

DOI:10.1002/etc.5620091107

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractContinuous‐flow toxicity tests using the oil dispersant Corexit 9527s̊ were performed on the early life stages of four California marine species. Newly released zoospores of the giant kelp,Macrocystis pyrifera, embryos of the red abalone,Haliotis rufescens, 4‐d‐old juveniles of the mysid,Holmesimysis costataand 10‐d‐old larvae of the topsmelt,Atherinops affinis, were all used in triplicate 48‐ and 96‐h tests. Quantitative verification of dispersant concentrations using UV spectrophotometry was performed twice daily during testing. Results indicated growth of kelp gametophytes was significantly reduced at<2.4 ppm after a 48‐h exposure. Of the three animals tested, developing red abalone were the most sensitive (NOEC = 0.63 to 1.50 ppm; LC50 = 1.60 to 2.20 ppm). Mysid juveniles were intermediate in sensitivity (NOEC = 1.66 to 4.20 ppm; LC50 = 4.26 to 7.26 ppm), whereas topsmelt larvae were the least sensitive (NOEC = 12.27 to 14.18 ppm; LC50 =25.51 to 40.63 ppm). Reproducibility of test data was very high (coefficient of variation

ISSN:0730-7268    

DOI:10.1002/etc.5620091108

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractTo develop a database for use in designing sealed‐container bioassays, oxygen consumption and ammonia production rates were compared for eggs and newly hatched larvae of Japanese medaka(Oryzias latipes).At 23, 26 and 29°C, the total amount of oxygen required to hatch an egg (49 to 54 μg O2.egg−1) was independent of temperature, but total oxygen required at 20°C (77 μg O2.egg−1) was significantly greater. Eggs produced no measurable ammonia (TAmm), but newly hatched larva produced 14 ng TAmm.h−1.larva−1at 23°C and up to 48 ng TAmm.h−1.larva−1at 29°C. When exposure to free air was denied, (a) oxygen, not ammonia, was the limiting factor for normal egg development, and (b) newly hatched larvae were unable to inflat

ISSN:0730-7268    

DOI:10.1002/etc.5620091109

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractA laboratory bioassay is described for determining the bioavailability of contaminants from freshwater sediments. The bioassay consists of 10‐d exposures to whole sediments under flow‐through conditions. After testing five species, the fathead minnow(Pimephales promelas)and the earthworm(Lumbricus terrestris)were recommended for use in the test. When the availability of polychlorinated biphenyls (PCBs), Hg and Zn from Great Lakes sediments was examined in laboratory exposures, only the PCBs were accumulated. A field validation study demonstrated that the magnitude of accumulation in laboratory exposures was similar to that in organisms caged in the field. A protocol is recommended for using the test as a standardized bioaccumulation bioas

ISSN:0730-7268    

DOI:10.1002/etc.5620091110

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY