ISSN:0730-7268    

DOI:10.1002/etc.5620130101

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe fate of atrazine in biologically active laboratory‐scale granular activated carbon (GAC) reactors was studied through analysis of atrazine and its breakdown products in the influent and effluent water of the GAC reactor and sand reactor. The biological activity in the GAC bed, influent, and effluent was monitored by measuring the heterotrophic plate count (HPC) bacteria. The HPC reached equilibrium concentrations of 1.37 to 1.67 × 106colony‐forming units per milliliter (cfu/ml) after two to three weeks in the GAC effluents, and 7.65 × 103cfu/ml after four to six weeks in the effluent of the sand reactor. A solution of natural ground water spiked with 200 μg/L atrazine was continuously applied to the biologically active reactors at a flow rate of 5 ml/min for 70 d. Composite weekly samples of the effluent were extracted and analyzed for atrazine, deethylatrazine, and deisopropylatrazine using GC. Hydroxyatrazine was analyzed by liquid chromatography. Deethylatrazine was consistently detected in the effluent of the sand reactor only, and hydroxyatrazine was detected in the effluent of one of the GAC reactors, before complete development of bacterial activity. The percentage of atrazine disappearance was 98.10 to 98.67% in the GAC reactors and 42.10% in the sand reactor. The results suggest the possibility of complete mineralization of atrazine at 200 μg/L in biologically active GAC, with significantly low exportation of toxic breakdown products to the effluen

ISSN:0730-7268    

DOI:10.1002/etc.5620130102

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractFrequencies of allozyme genotypes are being used as population‐level indicators of environmental heavy‐metal contamination. A genotype of glucose phosphate isomerase,Gpi‐238/38, of mosquitofish (Gambusia holbrooki) has been identified as “mercury‐sensitive” in an acute toxicity assay. Partially purified preparations of GPI‐2 38/38 and GPI‐2 100/100 were assayed to determine differences in maximum gluconeogenic reaction velocity at seven mercury (added as HgCl2) concentrations, 15 to 960 nM Hg. Log‐Probit analysis of the inhibition curves indicated that the log(IC50) (log10of the Hg concentration causing a 50% reduction in reaction velocity) for GPI‐2 100/100 was significantly lower than that for GPI‐2 38/38, even though GPI‐2 100/100 initial uninhibited reaction velocity was greater than that of GPI‐2 38/38. Although the mechanism of inhibition was not experimentally determined, under the assumption of noncompetitive interaction between Hg and GPI‐2, the inhibitor dissociation constants (95% asymptotic C.I.) for GPI‐2 100/100 and GPI‐2 38/38 were estimated from the log (IC50) as 204 nM Hg (155‐269 nM Hg) and 479 nM Hg (363‐617 nM Hg), respectively. These results suggested that Hg susceptibility related to theGpi‐238/38genotype in acute toxicity assays was likely not due to

ISSN:0730-7268    

DOI:10.1002/etc.5620130103

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractCompositing of sediment or water samples provides an opportunity to screen numerous samples economically if contamination is a relatively rare occurrence. However, standard compositing procedures simply identify that contamination exists among one or more constituent samples of the composite. Using a two‐way compositing strategy, detected contamination in composited samples can be attributed directly to constituent samples without further analyses. Procedure is illustrated using benthic sediment samples contaminated with crude oil following an oil spill. The proposed compositing scheme has a relative efficiency ofn/2 compared to the analysis of individual samples whenn2is the number of samples screened (e.g.,n2= 16 samples, relative efficiency is 4/2 = 2

ISSN:0730-7268    

DOI:10.1002/etc.5620130104

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractA comparison was made between biological and chemical mineralization of pyridine, anN‐heterocyclic pollutant, in a liquid culture and a slurry of ground water and subsurface sediment. A bacterial culture of anAlcaligenessp. that degrades pyridine was found to be more effective at oxidizing [2,6‐14C]pyridine to14CO2than Fenton's reagent.Alcaligenessp. converted 73.1% of the14C‐labeled pyridine to14CO2, whereas the Fenton reagent converted 65.6% of the compound. In the case of bacteria, the remaining chemical was incorporated primarily into biomass (9.2%), whereas the remaining pyridine was converted to unidentified products (16.3%) by the Fenton reagent. However, based on chromatographic analysis, these compounds were not mono‐hydroxylated pyridines. Mineralization of pyridine by Fenton's reagent was affected by the concentration of H2O2and by the concentration and oxidation state of available iron. Maximal mineralization occurred at a concentration of more than 0.15% H2O2(44 mM), 1 mM Fe3+, or 2 mM Fe2+. Furthermore, the rates of both microbial and chemical mineralization were influenced by the initial pyridine concentration. Maximum specific rates of mineralization were 6.5 μg/h/mg biomass for the bacteria and 2.7 μg/h/mg Fe2+for the Fenton reagent. The feasibility of using Fenton's reagent for treating ground water and subsurface sediments polluted with pyridine was found to be limited, because only 24.5% of the pyridine was converted to CO2. In contrast, when cultures of theAlcaligenessp. were used to treat ground water, as much as 54.4% of the labeled compound was mineralize

ISSN:0730-7268    

DOI:10.1002/etc.5620130105

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractAn effluent sample from a municipal wastewater treatment plant that receives a heavy loading from two textile dyeing facilities was tested for a variety of photoeffects. Solar irradiation of solutions containing the effluent produced evidence for sensitized formation of transient oxidants, primarily singlet oxygen; dye‐sensitized photooxidation of several phenols; and photoinhibition ofEscherichia col

ISSN:0730-7268    

DOI:10.1002/etc.5620130106

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractSexual dimorphism in fourth‐instar larvae and adults was studied forChironomus riparius.Wet weight of fourth‐instar male chironomids was on average 29.4% lower than that of fourth‐instar female chironomids at day 10 post‐hatch of eggs, when organisms were reared individually in 250‐ml beakers with 60 g sediment. This weight differential continued to the adult stage and was enhanced with males weighing 39.8% less than females (dry weight). When animals were reared in groups of 15 larvae per beaker, differences between the sexes in larval wet weight were not statistically significant, but males were still 7.4% smaller than females; however, adult males weighed an average of 42.7% less than females upon emergence. Stage of development (fourth instar) was confirmed by head capsule measurement; no significant differences in head capsule widths were detected between the sexes. Animals reared alone, regardless of sex, weighed more than animals reared as a group, indicating that initial larval densities and size of bioassay container can significantly affect larval growth. The probability of making a type I error in sediment toxicity tests due to sexual dimorphism in weight was estimated to be only 3% when dimorphism was most enhanced, that is, for animals reared individually. The effect of dimorphism on data interpretation when animals are reared in groups of 15 to 50 animals per container is thought to be minimal. It is recommended that both larval weight and head capsule width (millimeters) be measured as end points in sediment toxicity tests to differentiate reduced growth from retardation of instar de

ISSN:0730-7268    

DOI:10.1002/etc.5620130107

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractEuropean carp (Cyprinus carpio) exposed to highly treated pulp mill effluent in Lake Coleman, a shallow‐water lake in southern Victoria, Australia, had significantly elevated hepatic microsomal EROD levels relative to reference fish from a nearby unexposed water body (Dowds and Heart morasses). Mean hepatic microsomal EROD activity appeared to be correlated with site adsorbable organic halogen (AOX) levels, with a simple linear regression yielding the equationY= 0.059X+ 1.415 (r2= 0.93,n= 5), whereYis mean EROD activity in nanomoles per minute per milligram andXis mean AOX concentration in micrograms per liter. Mean liver EROD activity was poorly related with fish muscle‐tissue extractable organic halogen (EOX) and sediment EOX concentrations. Hepatic microsomal EROD activity also appeared to be correlated with the low levels of PCDD/PCDFs measured in carp muscle (1.0‐4.0 ppt TCDD international toxic equivalents (TEs) in effluent‐exposed fish muscle compared to 0.48‐0.64 ppt TEs in reference fish muscle). Simple linear regression of mean EROD activity in carp liver with the mean fish muscle dioxin content yielded the equationY= 6.514X+ 5.754 (n= 4,r2= 0.88), whereYis mean EROD activity in nanomoles per minute per milligram andXis mean dioxin concentration in ppt of TCDD TEs. Hepatic microsomal ECOD activity, however, was not significantly different at any exposure site from the reference sites. Overall, Lake Coleman contained between 4.5 and 9.3 times the water AOX levels, 0.8 and 13.7 times the sediment EOX levels, 1.5 and 2.2 times the carp muscle‐fat EOX levels, 5.0 and 5.3 times the carp whole‐muscle TCDD toxic equivalents, and 6.5 times the carp fat TCDD toxic equivalents, compared to the Dowds and Heart morass reference samples. Within Lake Coleman, mean liver microsomal EROD activity levels were 2.3 to 6.3 times higher than the Dowds and Heart reference sites, respectively. Tissue concentrations of PCDD/PCDF and water AOX levels reduced with increasing distance from the effluent point source. Carp liver microsomal EROD represented a good biomarker of exposure to low levels of organochlorine contaminants from well‐treated pul

ISSN:0730-7268    

DOI:10.1002/etc.5620130108

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractAcute toxicity tests were conducted to determine (a) the individual and interactive effects of water temperature (7, 12, 17°C), pH (6 5, 7 5, 8 5, 9 5), and time on the toxicity of terbufos, trichlorfon, 4 nitrophenol, and 2,4‐dinitrophenol to rainbow trout (Oncorhynchus mykiss) and the amphipodGammarus pseudohmnaeus, and (b) the individual and interactive effects of water temperature and pH on chemical bioconcentration during acute tests with rainbow trout andGammarusexposed to terbufos, 4 nitrophenol, and 2,4 dinitrophenol The toxicity of all four chemicals was significantly affected by pH in all tests, except forGammarusexposed to terbufos The toxicity of terbufos to rainbow trout andGammaruswas less at pH 7 5 than at higher or lower pH The toxicity of both nitrophenols decreased as pH increased, whereas the toxicity of trichlorfon increased with pH The effect of pH on trichlorfon toxicity decreased with temperature Temperature significantly affected the toxicity of all four chemicals to both species Toxicity increased with temperature in all tests, except for rainbow trout exposed to nitrophenols, toxicity decreased as temperature increased for rainbow trout Chemical bioconcentration was also significantly af fected by temperature and pH and was directly related to toxicity in most tests Significant interactive effects between toxicity modifying factors were also frequently observed Temperature and pH effects on chemical toxicity need to be consid ered in chemical hazard assessment to ensure adequate protection of aquatic organi

ISSN:0730-7268    

DOI:10.1002/etc.5620130109

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe toxicities of two industrial chemicals (4‐nitrophenol and 2,4‐dinitrophenol) and two organophosphate insecticides (terbufos and trichlorfon) to juvenile grass shrimp (Palaemonetesspp.) and sheepshead minnows (Cyprinodon variega‐tus) were determined by static, 96‐h toxicity tests in a factorial design with 12 combinations of salinity and temperature (15, 20, 25, 30 ppt × 17, 22, 27°C). Concentrations of the toxicants, including bioconcentration, were determined as appropriate by gas or liquid chromatography and the use of14C‐labeled compounds. The 96‐h LC50s for 4‐nitrophenol ranged from 12 to 31 mg/L and for 2,4‐dinitrophenol from 13 to 50 mg/L. Toxicity decreased as salinity increased for 4‐nitrophenol and both test organisms. Toxicity decreased as salinity increased for 2,4‐dinitrophenol and sheepshead minnows, but toxicity to grass shrimp increased as salinity increased. Toxicity decreased with increased temperature for grass shrimp exposed to 2,4‐dinitrophenol and sheepshead minnows exposed to 4‐nitrophenol, increased with temperature for sheepshead minnows exposed to 2,4‐dinitrophenol, and no change was observed for grass shrimp exposed to 4‐nitrophenol. Bioconcentration of phenols in both test organisms increased as concentration increased. The 96‐h LC50s for terbufos ranged from 3.4 to 6.6 μg/L and for trichlorfon from 6.3 to 19,300 μg/L. Terbufos and trichlorfon toxicity to grass shrimp and sheepshead minnows increased with increased temperature. BCFs for terbufos were greater in sheepshead minnows than grass shrimp,

ISSN:0730-7268    

DOI:10.1002/etc.5620130110

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY