A microcapillary assay technique was developed to assess effects of pollutants on the chemoattraction of the ciliate, Tetrahymena pyriformis. Parameters in the protocol such as starvation period, exposure period, and trough design were standardized in an effort to obtain consistent results. Cadmium, phenol, and naphthalene were tested for effects on ciliates' chemoattraction to 0.15% yeast extract. All three toxicants inhibited chemoattraction; cadmium had the greatest effect, followed by naphthalene and phenol, respectively. The percent inhibition of chemoattraction for each concentration was used to determine EC50 values for both 1 and 5 h exposures. Results show that the chemoattraction assay may provide a rapid, inexpensive, and sensitive asessment of aquatic toxicity. Inclusion of a protozoan assay fills the existing taxonomic gap in the routine battery of toxicity tests used for many hazard evaluations.
{"title":"Development of a protozoan chemoattraction bioassay for evaluating toxicity of aquatic pollutants.","authors":"R. O. Roberts, S. Berk","doi":"10.1002/TOX.2540050307","DOIUrl":"https://doi.org/10.1002/TOX.2540050307","url":null,"abstract":"A microcapillary assay technique was developed to assess effects of pollutants on the chemoattraction of the ciliate, Tetrahymena pyriformis. Parameters in the protocol such as starvation period, exposure period, and trough design were standardized in an effort to obtain consistent results. \u0000 \u0000 \u0000 \u0000Cadmium, phenol, and naphthalene were tested for effects on ciliates' chemoattraction to 0.15% yeast extract. All three toxicants inhibited chemoattraction; cadmium had the greatest effect, followed by naphthalene and phenol, respectively. The percent inhibition of chemoattraction for each concentration was used to determine EC50 values for both 1 and 5 h exposures. \u0000 \u0000 \u0000 \u0000Results show that the chemoattraction assay may provide a rapid, inexpensive, and sensitive asessment of aquatic toxicity. Inclusion of a protozoan assay fills the existing taxonomic gap in the routine battery of toxicity tests used for many hazard evaluations.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"131 1","pages":"279-292"},"PeriodicalIF":0.0,"publicationDate":"1990-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73011067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Decolorization and biodegradation of the azo dye methyl red (2′-carboxy-4-N,N-dimethylamino-azobenzene) in shaking and static cultures of the strict aerobe Acetobacter liquefaciens S-1 were demonstrated by the disappearance of the brownish orange color of the methyl red containing medium (pH 7.5), by the decrease in absorption maximum of methyl red, and by the identification of two compounds 2-aminobenzoic acid (anthranilic acid) and N,N′-dimethyl-p-phenylene diamine (4-N,N-dimethylamino-aniline) formed by reductive cleavage of methyl red in parallel with incubation time. Decolorization of methyl red was essentially completed within 17 h of incubation in both shaking and static cultures, which contained 1 g/L of (NH4)2SO4 as nitrogen source, 1% ethanol as carbon source, and up to 400 ppm of methyl red. Cells of A. liquefaciens S-1 were able to metabolize methyl red as sole nitrogen source for growth, although the time required to achieve high decolorization efficiency (98%) of methyl red was considerably longer (72 h) under this condition.
在严格需氧菌液化醋酸杆菌S-1的振荡和静态培养中，偶氮染料甲基红(2′-羧基-4- n, n -二甲氨基-偶氮苯)的脱色和生物降解表现为:含甲基红的培养基(pH为7.5)褐橙色消失，甲基红吸收最大值减小;通过甲基红还原裂解生成的2-氨基苯甲酸(邻氨基苯甲酸)和N,N ' -二甲氨基苯胺(4-N,N-二甲氨基苯胺)两种化合物与孵育时间平行鉴定。在震荡培养和静态培养中，甲基红的脱色基本上在17小时内完成，其中含有1 g/L的(NH4)2SO4作为氮源，1%的乙醇作为碳源，高达400 ppm的甲基红。液化芽孢杆菌S-1的细胞能够代谢甲基红作为生长的唯一氮源，尽管在这种条件下甲基红达到98%的脱色效率所需的时间要长得多(72 h)。
{"title":"Decolorization and biodegradation of methyl red by acetobacter liquefaciens","authors":"K. So, P. Wong, Kwong‐Yu Chan","doi":"10.1002/TOX.2540050303","DOIUrl":"https://doi.org/10.1002/TOX.2540050303","url":null,"abstract":"Decolorization and biodegradation of the azo dye methyl red (2′-carboxy-4-N,N-dimethylamino-azobenzene) in shaking and static cultures of the strict aerobe Acetobacter liquefaciens S-1 were demonstrated by the disappearance of the brownish orange color of the methyl red containing medium (pH 7.5), by the decrease in absorption maximum of methyl red, and by the identification of two compounds 2-aminobenzoic acid (anthranilic acid) and N,N′-dimethyl-p-phenylene diamine (4-N,N-dimethylamino-aniline) formed by reductive cleavage of methyl red in parallel with incubation time. Decolorization of methyl red was essentially completed within 17 h of incubation in both shaking and static cultures, which contained 1 g/L of (NH4)2SO4 as nitrogen source, 1% ethanol as carbon source, and up to 400 ppm of methyl red. Cells of A. liquefaciens S-1 were able to metabolize methyl red as sole nitrogen source for growth, although the time required to achieve high decolorization efficiency (98%) of methyl red was considerably longer (72 h) under this condition.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"45 1","pages":"221-235"},"PeriodicalIF":0.0,"publicationDate":"1990-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84896751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The toxic effect of single organic contaminants to aquatic biota is relatively easy to assess using classic aquatic toxicity bioassays. Unfortunately, contaminants are present in the aquatic environment in mixtures of unknown composition. Moreover, antagonistic and synergistic interactions make the prediction of the real environmental hazard posed by organic contaminants more complicated. A mathematical algorithm has been developed to predict the toxicity of mixtures of organic contaminants to aquatic biota using toxicity data for the individual components of the mixture. The Microtox® toxicity bioassay was used to obtain the toxicity data for a set of chlorinated phenols that were used as test compounds to validate the model. The unique characteristics of the Microtox bioassay make it a perfect tool to confirm experimentally the ability of the model to estimate the combined toxic effect of mixtures of organic contaminants.
{"title":"Toxicity of mixtures of aquatic contaminants using the luminescent bacteria bioassay","authors":"J. Ribó, F. Rogers","doi":"10.1002/TOX.2540050203","DOIUrl":"https://doi.org/10.1002/TOX.2540050203","url":null,"abstract":"The toxic effect of single organic contaminants to aquatic biota is relatively easy to assess using classic aquatic toxicity bioassays. Unfortunately, contaminants are present in the aquatic environment in mixtures of unknown composition. Moreover, antagonistic and synergistic interactions make the prediction of the real environmental hazard posed by organic contaminants more complicated. A mathematical algorithm has been developed to predict the toxicity of mixtures of organic contaminants to aquatic biota using toxicity data for the individual components of the mixture. The Microtox® toxicity bioassay was used to obtain the toxicity data for a set of chlorinated phenols that were used as test compounds to validate the model. The unique characteristics of the Microtox bioassay make it a perfect tool to confirm experimentally the ability of the model to estimate the combined toxic effect of mixtures of organic contaminants.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"79 1","pages":"135-152"},"PeriodicalIF":0.0,"publicationDate":"1990-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78217534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As part of the process of risk evaluation for workplace health and environmental protection, a battery of biological assays and a management presentation format for the battery have been developed for use at EG & G Rocky Flats, Inc. The battery consists of four acute (two bacterial, one human cell, one nematode) and two genetic (bacterial and nematode) assays. The nematode assay also gives information on chronic toxicity and an overall fitness factor. The battery was shown to be effective in detecting toxicity of eight metals and phenol, substances that are used at this plant and that react through a variety of toxic mechanisms. The presentation format allows management to very quickly determine where the most serious toxicity problems are located and effectively monitor progress in the cleanup of these situations. In addition, the format can be used to monitor effects of procedural changes in development and production.
作为工作场所健康和环境保护风险评估进程的一部分，制定了一套生物分析方法和一套管理说明格式，供EG & G Rocky Flats公司使用。该电池包括四种急性(两种细菌，一种人类细胞，一种线虫)和两种遗传(细菌和线虫)分析。线虫试验还提供了慢性毒性和整体健康因子的信息。该电池在检测八种金属和苯酚的毒性方面被证明是有效的，这些物质在该工厂使用，并通过各种毒性机制发生反应。演示格式允许管理层非常快速地确定最严重的毒性问题所在，并有效地监控这些情况的清理进展。此外，该格式还可用于监测开发和生产过程中程序变化的影响。
{"title":"A bioassessment battery for use in an industrial setting: a new management approach","authors":"S. M. Clarke, C. Barrick, M. Samoiloff","doi":"10.1002/TOX.2540050204","DOIUrl":"https://doi.org/10.1002/TOX.2540050204","url":null,"abstract":"As part of the process of risk evaluation for workplace health and environmental protection, a battery of biological assays and a management presentation format for the battery have been developed for use at EG & G Rocky Flats, Inc. The battery consists of four acute (two bacterial, one human cell, one nematode) and two genetic (bacterial and nematode) assays. The nematode assay also gives information on chronic toxicity and an overall fitness factor. The battery was shown to be effective in detecting toxicity of eight metals and phenol, substances that are used at this plant and that react through a variety of toxic mechanisms. The presentation format allows management to very quickly determine where the most serious toxicity problems are located and effectively monitor progress in the cleanup of these situations. In addition, the format can be used to monitor effects of procedural changes in development and production.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"10 1","pages":"153-166"},"PeriodicalIF":0.0,"publicationDate":"1990-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84642313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dickson L. S. Liu, R. Maguire, B. Dutka, G. Pacepavicius
Toxicity and biodegradability are major factors affecting the fate and behavior of an organic contaminant in the environment. In this report, 2,4-dinitrotoluene (DNT), an important industrial chemical, was used as a model toxicant to demonstrate that toxicity and biodegradability are intimately related in determining a chemical's effect and impact on the total ecosystem. DNT was found to be aerobically stable, but could undergo anaerobic biotransformation with the formation of three metabolites. One of the metabolites, namely 2-nitroso-4-nitrotoluene, was extremely toxic to the six test bacterial isolates, while the other two aminonitro metabolites and the parent compound DNT were much less toxic or nontoxic to the bacterial cultures. It is suggested that the incorporation of some known metabolites into short-term bioassay procedures could increase the reliability of these tests in the impact assessment of toxic chemicals on the environment. In addition, the difference between toxicity data generated from short-term bioassay procedures and those from long-term toxicological studies was also delineated from a biochemical viewpoint.
{"title":"Rationale for including metabolites in chemical toxicity bioassay","authors":"Dickson L. S. Liu, R. Maguire, B. Dutka, G. Pacepavicius","doi":"10.1002/TOX.2540050206","DOIUrl":"https://doi.org/10.1002/TOX.2540050206","url":null,"abstract":"Toxicity and biodegradability are major factors affecting the fate and behavior of an organic contaminant in the environment. In this report, 2,4-dinitrotoluene (DNT), an important industrial chemical, was used as a model toxicant to demonstrate that toxicity and biodegradability are intimately related in determining a chemical's effect and impact on the total ecosystem. DNT was found to be aerobically stable, but could undergo anaerobic biotransformation with the formation of three metabolites. One of the metabolites, namely 2-nitroso-4-nitrotoluene, was extremely toxic to the six test bacterial isolates, while the other two aminonitro metabolites and the parent compound DNT were much less toxic or nontoxic to the bacterial cultures. It is suggested that the incorporation of some known metabolites into short-term bioassay procedures could increase the reliability of these tests in the impact assessment of toxic chemicals on the environment. In addition, the difference between toxicity data generated from short-term bioassay procedures and those from long-term toxicological studies was also delineated from a biochemical viewpoint.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"256 1","pages":"179-188"},"PeriodicalIF":0.0,"publicationDate":"1990-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76357249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The artifical substrata-microcosm method is intended for use in predicting direct and indirect effects of chemicals and chemical mixtures on whole, naturally derived, aquatic microbial communities (ecosystem surrogates). The method includes examination of effects on microbial production, respiration, nutrient dynamics, enzyme activities, and species richness
{"title":"Technical methods section a microcosm procedure for estimating ecological effects of chemicals and mixtures","authors":"J. Pratt, N. Bowers","doi":"10.1002/TOX.2540050207","DOIUrl":"https://doi.org/10.1002/TOX.2540050207","url":null,"abstract":"The artifical substrata-microcosm method is intended for use in predicting direct and indirect effects of chemicals and chemical mixtures on whole, naturally derived, aquatic microbial communities (ecosystem surrogates). The method includes examination of effects on microbial production, respiration, nutrient dynamics, enzyme activities, and species richness","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"44 1","pages":"189-205"},"PeriodicalIF":0.0,"publicationDate":"1990-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78548934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The authors adapted microtitration techniques to the SOS Chromotest, and thereby established a simple and reliable modified genotoxicity test: the Microtitration SOS Chromotest. This test employs microtitration techniques and photometric analysis with numerical readout. These data are integrated into the computerized data processing program Statistical Analysis System to obtain genotoxicity and toxicity results of a chemical or chemical mixture within 16 h. In order to test the applicability of the new system, the genotoxicity and toxicity of 22 pesticides were studied. A two-sample t test was employed to determine the level of significance (p captan > folpet > dinoseb > ferbam > linuron > alachlor > phosmet > cacodylic acid. The addition of rat liver S9 mix does not transform the nongenotoxic pesticides tested into genotoxic forms but significantly decreases the inducing ability of most positive pesticides. The Microtitration SOS Chromotest is rapid and efficient in providing evidence for decision-making related to cleanup of chemical spills and discharges where time is a critical factor. This method maintains its high accuracy and sensitivity compared with conventionally used assays. The studies of pesticide genotoxicity using this test confirm the applicability, reliability, and sensitivity of the Microtitration SOS Chromotest as a simple, efficient, and rapid genotoxicity prescreening system as well as an excellent research tool for genotoxic mechanism studies.
{"title":"Genotoxicity of 22 pesticides in microtitration SOS chromotest","authors":"Hao Xu, K. Schurr","doi":"10.1002/TOX.2540050102","DOIUrl":"https://doi.org/10.1002/TOX.2540050102","url":null,"abstract":"The authors adapted microtitration techniques to the SOS Chromotest, and thereby established a simple and reliable modified genotoxicity test: the Microtitration SOS Chromotest. This test employs microtitration techniques and photometric analysis with numerical readout. These data are integrated into the computerized data processing program Statistical Analysis System to obtain genotoxicity and toxicity results of a chemical or chemical mixture within 16 h. \u0000 \u0000 \u0000 \u0000In order to test the applicability of the new system, the genotoxicity and toxicity of 22 pesticides were studied. A two-sample t test was employed to determine the level of significance (p captan > folpet > dinoseb > ferbam > linuron > alachlor > phosmet > cacodylic acid. The addition of rat liver S9 mix does not transform the nongenotoxic pesticides tested into genotoxic forms but significantly decreases the inducing ability of most positive pesticides. \u0000 \u0000 \u0000 \u0000The Microtitration SOS Chromotest is rapid and efficient in providing evidence for decision-making related to cleanup of chemical spills and discharges where time is a critical factor. This method maintains its high accuracy and sensitivity compared with conventionally used assays. The studies of pesticide genotoxicity using this test confirm the applicability, reliability, and sensitivity of the Microtitration SOS Chromotest as a simple, efficient, and rapid genotoxicity prescreening system as well as an excellent research tool for genotoxic mechanism studies.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"2014 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"1990-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86761117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Technical methods section method for measuring toxicity of suspended particulates in waters","authors":"S. Rao, K. Kwan","doi":"10.1002/TOX.2540050108","DOIUrl":"https://doi.org/10.1002/TOX.2540050108","url":null,"abstract":"","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"1 1","pages":"91-101"},"PeriodicalIF":0.0,"publicationDate":"1990-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83149168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As of December 31, 1988, the U.S. Environmental Protection Agency (EPA) had published 49 Federal Register (FR) notices acknowledging, proposing, or requiring development of bioconcentration, chemical fate, or environmental effects testing data under Section 4 of the Toxic Substances Control Act (TSCA). These FR notices included 5 Decisions Not to Test (DNTs) that acknowledged industry testing, 19 Notices of Proposed Rulemaking (NPRs) that proposed testing by industry, 9 Notices of Final Rulemaking (NFRs), and 2 Consent Orders (COs) that required industry testing as well as 7 proposed and 7 final Negotiated Testing Agreements (NTAs). Two bioconcentration, 12 chemical fate, and 28 environmental effects tests were submitted to the EPA by industry as a result of issuing DNTs. Industry completed 3 bioconcentration, 86 chemical fate, and 151 environmental effects tests after publication of NTAs. Two bioconcentration, 11 chemical fate, and 14 environmental effects tests were completed as a result of publishing NFRs; 1 chemical fate and 5 environmental effects tests were completed under a CO. As of December 31, 1988, a total of 7 bioconcentration, 110 chemical fate, and 234 environmental effects tests had been completed under TSCA Section 4.
{"title":"Bioconcentration, chemical fate, and environmental effects testing under section 4 of the Toxic Substances Control Act†","authors":"John D. Walker","doi":"10.1002/TOX.2540050106","DOIUrl":"https://doi.org/10.1002/TOX.2540050106","url":null,"abstract":"As of December 31, 1988, the U.S. Environmental Protection Agency (EPA) had published 49 Federal Register (FR) notices acknowledging, proposing, or requiring development of bioconcentration, chemical fate, or environmental effects testing data under Section 4 of the Toxic Substances Control Act (TSCA). These FR notices included 5 Decisions Not to Test (DNTs) that acknowledged industry testing, 19 Notices of Proposed Rulemaking (NPRs) that proposed testing by industry, 9 Notices of Final Rulemaking (NFRs), and 2 Consent Orders (COs) that required industry testing as well as 7 proposed and 7 final Negotiated Testing Agreements (NTAs). Two bioconcentration, 12 chemical fate, and 28 environmental effects tests were submitted to the EPA by industry as a result of issuing DNTs. Industry completed 3 bioconcentration, 86 chemical fate, and 151 environmental effects tests after publication of NTAs. Two bioconcentration, 11 chemical fate, and 14 environmental effects tests were completed as a result of publishing NFRs; 1 chemical fate and 5 environmental effects tests were completed under a CO. As of December 31, 1988, a total of 7 bioconcentration, 110 chemical fate, and 234 environmental effects tests had been completed under TSCA Section 4.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"7 1","pages":"61-75"},"PeriodicalIF":0.0,"publicationDate":"1990-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89969396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Because the productivity of terrestrial ecosystems is directly related to microbial nutrient cycling, understanding the effects of chemical contaminants on soil microbial processes is important. This study examined the effects of two model chemicals—Roundup (glyphosate) and N-Serve (nitrapyrin)—on nitrifying organisms in static, perfusion, and continuous-flow culture systems. Experimental concentrations were approximately 1, 10, and 100 × the spot application rate. Both N-Serve and Roundup were shown to inhibit nitrification in the treated soils. Roundup significantly reduced nitrification at 6.8 and 68 mg g−1 dry soil. N-Serve (nitrapyrin) completely inhibited nitrification at levels greater than 42 μ g−1 dry soil in all cultural methods. In comparative studies with static batch and perfusion culture techniques, the continuous-flow system proved to be both reliable and useful in the culture of nitrifying bacteria. This method provides an alternative to traditional culture techniques in measuring chemical effects on microbial geochemical cycles and provides a new method for use in toxicity testing.
由于陆地生态系统的生产力与微生物养分循环直接相关，因此了解化学污染物对土壤微生物过程的影响非常重要。本研究考察了两种模式化学物质——农达(草甘膦)和N-Serve(硝基吡啶)在静态、灌注和连续流培养系统中对硝化生物的影响。实验浓度分别为现场施药率的1倍、10倍和100倍。N-Serve和农达对处理过的土壤的硝化作用均有抑制作用。草甘膦显著降低了6.8 mg g - 1和68 mg g - 1干燥土壤的硝化作用。在所有培养方法中，N-Serve (nitrapyrin)在高于42 μ g−1的干土水平下完全抑制硝化作用。通过与静态间歇培养和灌注培养技术的对比研究，证明了连续流系统在硝化细菌的培养中是可靠的和有用的。该方法为测定微生物地球化学循环的化学效应提供了一种替代传统培养技术的方法，并为毒性检测提供了一种新的方法。
{"title":"A continuous-flow method for measuring effects of chemicals on soil nitrification.","authors":"A. N. Rhodes, C. W. Hendricks","doi":"10.1002/TOX.2540050107","DOIUrl":"https://doi.org/10.1002/TOX.2540050107","url":null,"abstract":"Because the productivity of terrestrial ecosystems is directly related to microbial nutrient cycling, understanding the effects of chemical contaminants on soil microbial processes is important. This study examined the effects of two model chemicals—Roundup (glyphosate) and N-Serve (nitrapyrin)—on nitrifying organisms in static, perfusion, and continuous-flow culture systems. Experimental concentrations were approximately 1, 10, and 100 × the spot application rate. Both N-Serve and Roundup were shown to inhibit nitrification in the treated soils. Roundup significantly reduced nitrification at 6.8 and 68 mg g−1 dry soil. N-Serve (nitrapyrin) completely inhibited nitrification at levels greater than 42 μ g−1 dry soil in all cultural methods. \u0000 \u0000 \u0000 \u0000In comparative studies with static batch and perfusion culture techniques, the continuous-flow system proved to be both reliable and useful in the culture of nitrifying bacteria. This method provides an alternative to traditional culture techniques in measuring chemical effects on microbial geochemical cycles and provides a new method for use in toxicity testing.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"348 1","pages":"77-89"},"PeriodicalIF":0.0,"publicationDate":"1990-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74118607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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