J. Pratt, N. Bowers, B. R. Niederlehner, J. Cairns
Ecologically realistic laboratory and field simulated ecosystems (microcosms and mesocosms) are playing increasing roles in fate and effect testing of chemicals and mixtures. Controlled ecosystems allow evaluation of toxicant effects on collective and emergent ecosystem properties. Information is needed to evaluate the validity of test system responses, interpretability of results, and cost effectiveness of simulated ecosystem tests. We developed replicate microcosms using periphyton on polyurethane artificial substrates. Source communities were obtained from two ecosystems—a reservoir in Kentucky and a softwater pond in Virginia—and tested for effects of continuous inputs of phenol (up to 30 mg/L) over 21 days. System responses measured included several biomass estimators, net oxygen production, and protozoan species richness. Communities were generally insensitive to phenol input. Primary production in microcosms from both ecosystems was inhibited at phenol concentrations >10 mg/L and chlorophyll a concentrations were also depressed. Other biomass estimators (protein, hexosamine) were not affected or were stimulated at lower (⩽10 mg/L) phenol concentrations. Protozoan species numbers were not affected. Functional shifts in the communities preceded adverse structural effects. Effect levels were similar for both communities, although the more complex community with greater biomass (Kentucky) showed more significant responses than the simpler community (Virginia). Systems showed resistance to phenol levels that were actually toxic in standard single-species tests, suggesting that ecosystems may differ in magnitude and rate of response to some nonpersistent toxicants.
{"title":"Response of laboratory ecosystems to environmental stress: Effect of phenol","authors":"J. Pratt, N. Bowers, B. R. Niederlehner, J. Cairns","doi":"10.1002/TOX.2540040205","DOIUrl":"https://doi.org/10.1002/TOX.2540040205","url":null,"abstract":"Ecologically realistic laboratory and field simulated ecosystems (microcosms and mesocosms) are playing increasing roles in fate and effect testing of chemicals and mixtures. Controlled ecosystems allow evaluation of toxicant effects on collective and emergent ecosystem properties. Information is needed to evaluate the validity of test system responses, interpretability of results, and cost effectiveness of simulated ecosystem tests. We developed replicate microcosms using periphyton on polyurethane artificial substrates. Source communities were obtained from two ecosystems—a reservoir in Kentucky and a softwater pond in Virginia—and tested for effects of continuous inputs of phenol (up to 30 mg/L) over 21 days. System responses measured included several biomass estimators, net oxygen production, and protozoan species richness. Communities were generally insensitive to phenol input. Primary production in microcosms from both ecosystems was inhibited at phenol concentrations >10 mg/L and chlorophyll a concentrations were also depressed. Other biomass estimators (protein, hexosamine) were not affected or were stimulated at lower (⩽10 mg/L) phenol concentrations. Protozoan species numbers were not affected. Functional shifts in the communities preceded adverse structural effects. Effect levels were similar for both communities, although the more complex community with greater biomass (Kentucky) showed more significant responses than the simpler community (Virginia). Systems showed resistance to phenol levels that were actually toxic in standard single-species tests, suggesting that ecosystems may differ in magnitude and rate of response to some nonpersistent toxicants.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"67 1","pages":"161-174"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78997698","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}
Oxygen uptake coupled with nitrite oxidation by washed cell suspensions of Nitrobacter agilis was tested in the presence of copper, nickel, aluminum, uranyl, and molybdate ions. Copper ion was slightly stimulatory at low concentrations and strongly inhibitory at 17 mM. Molybdate ion showed either slight enhancement or no inhibition at all test concentrations. With the other test ions, inhibition of oxygen uptake was observed. Carbon dioxide fixation was generally more sensitive to metal ions than was oxygen uptake. Cytochrome reduction in washed cells of N. agilis was demonstrated in the presence and absence of metal ions. Cytochrome aa3 and cytochrome a1 (α-peak at 590 nm) were sensitive to aluminum, uranyl, and molybdate ions, whereas cytochrome c (β-peak at 520 nm) was insensitive to test ions. All metal ions inhibited the reduction of cytochrome a1 (γ-peak at 438 nm). This inhibition decreased when the concentration of copper and molybdate was increased to 1.7 mM. Only aluminum and nickel ions demonstrated a concentration-dependent inhibition of cytochrome a1 (438 nm). The test ions blocked the activity of cytochrome c (α-peak at 550 nm). The inhibition of cytochrome c at 415 nm (γ-peak) was also apparent.
{"title":"Influence of metals on oxygen uptake, carbon dioxide fixation, and cytochrome reduction in Nitrobacter Agilis","authors":"Y. Tsai, O. Tuovinen","doi":"10.1002/TOX.2540040207","DOIUrl":"https://doi.org/10.1002/TOX.2540040207","url":null,"abstract":"Oxygen uptake coupled with nitrite oxidation by washed cell suspensions of Nitrobacter agilis was tested in the presence of copper, nickel, aluminum, uranyl, and molybdate ions. Copper ion was slightly stimulatory at low concentrations and strongly inhibitory at 17 mM. Molybdate ion showed either slight enhancement or no inhibition at all test concentrations. With the other test ions, inhibition of oxygen uptake was observed. Carbon dioxide fixation was generally more sensitive to metal ions than was oxygen uptake. Cytochrome reduction in washed cells of N. agilis was demonstrated in the presence and absence of metal ions. Cytochrome aa3 and cytochrome a1 (α-peak at 590 nm) were sensitive to aluminum, uranyl, and molybdate ions, whereas cytochrome c (β-peak at 520 nm) was insensitive to test ions. All metal ions inhibited the reduction of cytochrome a1 (γ-peak at 438 nm). This inhibition decreased when the concentration of copper and molybdate was increased to 1.7 mM. Only aluminum and nickel ions demonstrated a concentration-dependent inhibition of cytochrome a1 (438 nm). The test ions blocked the activity of cytochrome c (α-peak at 550 nm). The inhibition of cytochrome c at 415 nm (γ-peak) was also apparent.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"152 1","pages":"185-198"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82527510","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}
Oxygen uptake coupled with nitrite oxidation by washed cell suspensions was not influenced by persulfate or tetrathionate. Carbon dioxide fixation was insensitive to tetrathionate, and in fact, an enhancement by tetrathionate was observed. Persulfate inhibited the fixation of carbon dioxide only at a high concentration (17 mM S2O2−8). Cytochrome reduction in washed cells of Nitrobacter agilis was demonstrated in the presence and absence of sulfooxyanions. Cytochrome aa3 and cytochrome a1 (α-peak at 590 nm) were sensitive to sulfooxyanions (sulfite, thiosulfate, metabisulfite, dithionate, persulfate, trithionate, and tetrathionate), whereas cytochrome c (β-peak at 520 nm) was insensitive to test ions. All sulfooxyanions inhibited the reduction of cytochrome a1 (γ-peak at 438 nm). This inhibition decreased when the concentration of sulfooxyanions was increased to 17 mM. The reduction of cytochrome c at 550 nm (α-peak) was blocked by the test ions and the inhibition of cytochrome c at 415 nm (γ-peak) was also apparent. Complete inhibition of cytochrome c (γ-peak) was observed in the presence of 17 mM persulfate.
{"title":"Influence of sulfooxyanions on oxygen uptake, carbon dioxide fixation, and cytochrome reduction in Nitrobacter agilis","authors":"Y. Tsai, O. Tuovinen","doi":"10.1002/TOX.2540040208","DOIUrl":"https://doi.org/10.1002/TOX.2540040208","url":null,"abstract":"Oxygen uptake coupled with nitrite oxidation by washed cell suspensions was not influenced by persulfate or tetrathionate. Carbon dioxide fixation was insensitive to tetrathionate, and in fact, an enhancement by tetrathionate was observed. Persulfate inhibited the fixation of carbon dioxide only at a high concentration (17 mM S2O2−8). Cytochrome reduction in washed cells of Nitrobacter agilis was demonstrated in the presence and absence of sulfooxyanions. Cytochrome aa3 and cytochrome a1 (α-peak at 590 nm) were sensitive to sulfooxyanions (sulfite, thiosulfate, metabisulfite, dithionate, persulfate, trithionate, and tetrathionate), whereas cytochrome c (β-peak at 520 nm) was insensitive to test ions. All sulfooxyanions inhibited the reduction of cytochrome a1 (γ-peak at 438 nm). This inhibition decreased when the concentration of sulfooxyanions was increased to 17 mM. The reduction of cytochrome c at 550 nm (α-peak) was blocked by the test ions and the inhibition of cytochrome c at 415 nm (γ-peak) was also apparent. Complete inhibition of cytochrome c (γ-peak) was observed in the presence of 17 mM persulfate.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"55 1","pages":"199-207"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85240528","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}
Biodegradation processes for pentachlorophenol (PCP) and a commercial PCP formulation were evaluated to delineate factors limiting the rate of PCP degradation in the aquatic environment. Analyses of the data on PCP disappearance and chloride ion release, as well as gas chromatography and UV-VIS (ultra-violet and visible spectroscopy) spectra of the fermentor broth strongly indicate that the bacterial culture acted on PCP by completely stripping off all the chloride ions from a molecule of PCP, rather than following the normal pattern of removing only one chloride ion at a time. The haloaromatic ring structure of PCP was completely broken down, and not channeled into the unproductive meta-cleavage pathway. Despite repeated transfers of the bacterial culture, an initial lag phase in PCP biodegradation was apparent in all experiments and was followed by a steady state, nearly linear rate of PCP degradation. Thus in the aquatic environment the biodegradation rate of a persistent contaminant is more likely to be regulated by whether or not this compartment has been previously subjected to a long or continuous exposure to a particular chemical. First-order kinetics alone cannot be used to predict accurately the fate of a persistent chemical in the environment, because of the inability of such a simple equation to accommodate the effects of rate-limiting factors such as the length of adaptation period on the overall biodegradation rate of a contaminant. For this reason, factors that may influence a chemical's biodegradability in the natural environment must be considered in the design of laboratory biodegradation experiments.
{"title":"Biodegradation of pentachlorophenol and its commercial formulation","authors":"Dickson L. S. Liu","doi":"10.1002/TOX.2540040202","DOIUrl":"https://doi.org/10.1002/TOX.2540040202","url":null,"abstract":"Biodegradation processes for pentachlorophenol (PCP) and a commercial PCP formulation were evaluated to delineate factors limiting the rate of PCP degradation in the aquatic environment. Analyses of the data on PCP disappearance and chloride ion release, as well as gas chromatography and UV-VIS (ultra-violet and visible spectroscopy) spectra of the fermentor broth strongly indicate that the bacterial culture acted on PCP by completely stripping off all the chloride ions from a molecule of PCP, rather than following the normal pattern of removing only one chloride ion at a time. The haloaromatic ring structure of PCP was completely broken down, and not channeled into the unproductive meta-cleavage pathway. Despite repeated transfers of the bacterial culture, an initial lag phase in PCP biodegradation was apparent in all experiments and was followed by a steady state, nearly linear rate of PCP degradation. Thus in the aquatic environment the biodegradation rate of a persistent contaminant is more likely to be regulated by whether or not this compartment has been previously subjected to a long or continuous exposure to a particular chemical. First-order kinetics alone cannot be used to predict accurately the fate of a persistent chemical in the environment, because of the inability of such a simple equation to accommodate the effects of rate-limiting factors such as the length of adaptation period on the overall biodegradation rate of a contaminant. For this reason, factors that may influence a chemical's biodegradability in the natural environment must be considered in the design of laboratory biodegradation experiments.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"50 1","pages":"115-127"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90693858","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}
Protozoan communities developed on artificial substrates were used in a series of in situ and laboratory tests to evaluate the toxic potential of harbor sediments contaminated with polychlorinated biphenyl (PCB). Colonization dynamics in polluted and clean harbors were compared. Laboratory tests were community bioassays using standard techniques to produce sediment elutriate. Results of the in situ colonization and the community tests measuring structural changes (e.g., “decolonization”) were similar. In general, sediments from the contaminated harbor caused significant (p ⩽ 0.05) reductions in the number of taxa, in total protozoan abundance, and in phototroph abundance; however, the abundance of heterotrophic species increased in some in situ tests. Process-level parameters (e.g., respiration; island-epicenter colonization rates) were more sensitive than measurements of community structure. Phototrophs were more sensitive to sediment elutriate than were other trophic types. The information provided by this series of protozoan community tests is more complex than that provided by single-species bioassays. Although community tests may provide more information on the effects of sediment contamination on actual ecosystems than tests based on single species, they require careful interpretation to avoid misleading conclusions.
{"title":"Use of protozoan communities to assess the ecotoxicological hazard of contaminated sediments","authors":"M. S. Henebry, P. Ross","doi":"10.1002/TOX.2540040209","DOIUrl":"https://doi.org/10.1002/TOX.2540040209","url":null,"abstract":"Protozoan communities developed on artificial substrates were used in a series of in situ and laboratory tests to evaluate the toxic potential of harbor sediments contaminated with polychlorinated biphenyl (PCB). Colonization dynamics in polluted and clean harbors were compared. Laboratory tests were community bioassays using standard techniques to produce sediment elutriate. Results of the in situ colonization and the community tests measuring structural changes (e.g., “decolonization”) were similar. In general, sediments from the contaminated harbor caused significant (p ⩽ 0.05) reductions in the number of taxa, in total protozoan abundance, and in phototroph abundance; however, the abundance of heterotrophic species increased in some in situ tests. Process-level parameters (e.g., respiration; island-epicenter colonization rates) were more sensitive than measurements of community structure. Phototrophs were more sensitive to sediment elutriate than were other trophic types. The information provided by this series of protozoan community tests is more complex than that provided by single-species bioassays. Although community tests may provide more information on the effects of sediment contamination on actual ecosystems than tests based on single species, they require careful interpretation to avoid misleading conclusions.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"34 1","pages":"209-227"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78010142","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 public water supply has been implicated in gastrointestinal disorders in the United States, East Africa, and Australia, associated with the lysis of heavy blooms of cyanobacteria. The causative organisms include Microcystis, Anabaena, Aphanizomenon, and Oscillatoria. Using epidemiological techniques, we have shown significant increase in liver enzymes in blood, particularly γ-glutamyl transpeptidase, during a toxic bloom in the reservoir of a city. Therefore, public health awareness of the risks, and consequent action to control water blooms and remove harmful compounds from drinking water supplies, is required.
{"title":"Effects on human health of some toxic cyanobacteria (blue‐green algae) in reservoirs, lakes, and rivers","authors":"I. Falconer","doi":"10.1002/TOX.2540040206","DOIUrl":"https://doi.org/10.1002/TOX.2540040206","url":null,"abstract":"The public water supply has been implicated in gastrointestinal disorders in the United States, East Africa, and Australia, associated with the lysis of heavy blooms of cyanobacteria. The causative organisms include Microcystis, Anabaena, Aphanizomenon, and Oscillatoria. Using epidemiological techniques, we have shown significant increase in liver enzymes in blood, particularly γ-glutamyl transpeptidase, during a toxic bloom in the reservoir of a city. Therefore, public health awareness of the risks, and consequent action to control water blooms and remove harmful compounds from drinking water supplies, is required.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"20 1","pages":"175-184"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85794759","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}
A survey of sediment microbial activity and toxicity to Daphnia magna, Ceriodaphnia dubia, and Selenastrum capricornutum was conducted on two streams receiving numerous effluents in Ohio—the Little Scioto River and Dick's Creek. Microbial activity assays included alkaline phosphatase, dehydrogenase, β-galactosidase, β-glucosidase. Activity was compared to overlying water chemistry and revealed several statistically significant correlations. No macrofaunal assay toxicity was observed in Dick's Creek. Sediment toxicity was found at two stations in the Little Scioto River, and varied in degree and organism sensitivity with time of sampling. These results support earlier studies suggesting the need for multiple trophic-level assays in aquatic ecosystem evaluations of toxicant impacts.
{"title":"Evaluation of seven sediment toxicity tests and their relationships to stream parameters","authors":"G. A. Burton","doi":"10.1002/TOX.2540040204","DOIUrl":"https://doi.org/10.1002/TOX.2540040204","url":null,"abstract":"A survey of sediment microbial activity and toxicity to Daphnia magna, Ceriodaphnia dubia, and Selenastrum capricornutum was conducted on two streams receiving numerous effluents in Ohio—the Little Scioto River and Dick's Creek. Microbial activity assays included alkaline phosphatase, dehydrogenase, β-galactosidase, β-glucosidase. Activity was compared to overlying water chemistry and revealed several statistically significant correlations. No macrofaunal assay toxicity was observed in Dick's Creek. Sediment toxicity was found at two stations in the Little Scioto River, and varied in degree and organism sensitivity with time of sampling. These results support earlier studies suggesting the need for multiple trophic-level assays in aquatic ecosystem evaluations of toxicant impacts.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"68 1","pages":"149-159"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77199128","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}
Until recently, only three obligately aerobic bacteria (affiliated with the genus Pseudo-monas) that can grow with nitrilotriacetate (NTA) as their only source of carbon, nitrogen, and energy have been isolated and studied in pure culture. By employing a different isolation strategy than was used previously, several nonpseudomonads were isolated in pure culture from both soil and wastewater that are able to utilize NTA under aerobic growth conditions. Additionally, a denitrifying bacterium was isolated from river sediment that is able to utilize NTA in the absence of oxygen. These isolates have been characterized with respect to their cell morphology and physiology. The data collected so far do not allow classification of both the gram-negative and the gram-positive strains isolated, and the taxonomic position of the isolates remains obscure. However, properties like C1 utilization, production of acetoin, and nonmotility clearly indicate that the gram-negative strains do not belong to the genus Pseudomonas. Information is presented on the regulation of NTA-metabolizing enzymes in isolate TE 1 suggesting that these enzymes are inducible in this bacterium.
{"title":"Isolation, characterization, and physiology of bacteria able to degrade nitrilotriacetate","authors":"T. Egli, H. Weilenmann","doi":"10.1002/TOX.2540040104","DOIUrl":"https://doi.org/10.1002/TOX.2540040104","url":null,"abstract":"Until recently, only three obligately aerobic bacteria (affiliated with the genus Pseudo-monas) that can grow with nitrilotriacetate (NTA) as their only source of carbon, nitrogen, and energy have been isolated and studied in pure culture. By employing a different isolation strategy than was used previously, several nonpseudomonads were isolated in pure culture from both soil and wastewater that are able to utilize NTA under aerobic growth conditions. Additionally, a denitrifying bacterium was isolated from river sediment that is able to utilize NTA in the absence of oxygen. These isolates have been characterized with respect to their cell morphology and physiology. The data collected so far do not allow classification of both the gram-negative and the gram-positive strains isolated, and the taxonomic position of the isolates remains obscure. However, properties like C1 utilization, production of acetoin, and nonmotility clearly indicate that the gram-negative strains do not belong to the genus Pseudomonas. Information is presented on the regulation of NTA-metabolizing enzymes in isolate TE 1 suggesting that these enzymes are inducible in this bacterium.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"42 1","pages":"23-34"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91431663","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 effects of limiting nutrient to algal toxicity tests are discussed. It has been shown, through theoretical derivation, that EC50 values will vary with changes of nutrient concentration even if the effects of limiting nutrient and limiting toxicant on algal growth are independent. The variation in EC50's is governed by the degree of correlation between two variables: the tolerance and the activation level. The proposed theory shows a potential application for making a comparison of results obtained from different laboratories or methods and for applying laboratory results to field conditions.
{"title":"The effects of limiting nutrient to algal toxicity assessment: A theoretical approach","authors":"Chung‐Yuan Chen","doi":"10.1002/TOX.2540040105","DOIUrl":"https://doi.org/10.1002/TOX.2540040105","url":null,"abstract":"The effects of limiting nutrient to algal toxicity tests are discussed. It has been shown, through theoretical derivation, that EC50 values will vary with changes of nutrient concentration even if the effects of limiting nutrient and limiting toxicant on algal growth are independent. The variation in EC50's is governed by the degree of correlation between two variables: the tolerance and the activation level. The proposed theory shows a potential application for making a comparison of results obtained from different laboratories or methods and for applying laboratory results to field conditions.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"32 1","pages":"35-42"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73740476","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 toxicity of some mycotoxins, lactones and dicarboxylic anhydrides, insecticides, herbicides, and fungicides can be detected by means of bacterial assays. In addition, the order of magnitude of the toxicity can also be evaluated. Fifty-eight chemicals as well as extracts of peanuts, apple juices, and grains have been investigated in a test battery of three different kinds of assays. In cup plate diffusion assays a minimal amount of approximately 0. 1 mg/mL of mycotoxin may be detected by means of growth inhibition assays with Bacillus thuringiensis on one hand, and pigment synthesis inhibition assays with mutants of Serratia marcescens on the other hand. Swarming inhibition assays with the motile strains Azospirillum brasilense and Proteus mirabilis show the same sensitivity. Comparisons of our test battery with other bioassays, as well as with mammalian toxicity tests (LD50 values), reveal correlations between these kinds of assays in regard to the test substances.
{"title":"A test battery of bacterial toxicity assays and comparison with LD50 values","authors":"P. Lenz, R. Süssmuth, E. Seibel","doi":"10.1002/TOX.2540040106","DOIUrl":"https://doi.org/10.1002/TOX.2540040106","url":null,"abstract":"The toxicity of some mycotoxins, lactones and dicarboxylic anhydrides, insecticides, herbicides, and fungicides can be detected by means of bacterial assays. In addition, the order of magnitude of the toxicity can also be evaluated. \u0000 \u0000 \u0000 \u0000Fifty-eight chemicals as well as extracts of peanuts, apple juices, and grains have been investigated in a test battery of three different kinds of assays. In cup plate diffusion assays a minimal amount of approximately 0. 1 mg/mL of mycotoxin may be detected by means of growth inhibition assays with Bacillus thuringiensis on one hand, and pigment synthesis inhibition assays with mutants of Serratia marcescens on the other hand. Swarming inhibition assays with the motile strains Azospirillum brasilense and Proteus mirabilis show the same sensitivity. Comparisons of our test battery with other bioassays, as well as with mammalian toxicity tests (LD50 values), reveal correlations between these kinds of assays in regard to the test substances.","PeriodicalId":11824,"journal":{"name":"Environmental Toxicology & Water Quality","volume":"21 1","pages":"43-52"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75181320","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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