Intra‐ and intertreatment variability in reference toxicant tests: Implications for whole effluent toxicity testing programs

Moore, Dwayne R.J.; Warren-Hicks, William; Parkhurst, Benjamin R.; Teed, R. Scott; Baird, Rodger B.; Berger, R.; Denton, Debra L.; Pletl, James J.

doi:10.1002/etc.5620190112

Cited by 22 publications

(14 citation statements)

References 12 publications

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“…Calculating the CV allows one to relate the variation observed for one chemical to that of another. In this study, these values were always <20 for both 3C2B and MC, well within the acceptable range for aquatic toxicity tests as CV values were below the upper limit of 40 for intra-laboratory variability (Moore et al 2000; Hagen et al 2009, Piazza et al 2012). Previous studies with this system have reported CVs for the EC 50 similar to those obtained herein (Dawson et al 2014b, 2016).…”

Section: Discussionsupporting

confidence: 75%

Evaluation of consistency for multiple experiments of a single combination in the time-dependence mixture toxicity assay

Dawson

Pöch

2017

Toxicology Mechanisms and Methods

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Test-to-test consistency was evaluated for a single binary combination of organic chemicals using an assay that examined toxicity over multiple exposure times. Six experiments were conducted. The toxicity of 3-chloro-2-butanone (3C2B), methyl crotonate (MC) and the mixture (MX) was evaluated in each experiment at 15, 30 and 45-min of exposure using the Microtox® system. Concentration-response (x/y) curves were generated via the five-parameter logistic minus one-parameter (5PL-1P) curve-fitting function and used to develop predicted x/y curves for the dose-addition (DA) and independence (I) models of combined effect. A variety of toxicity (e.g., EC50) and time-dependent toxicity (TDT) endpoints, 5PL-1P parameters, and various combined effects metrics (e.g., MX/DA) were calculated. Test-to-test consistency was evaluated via the coefficient of variation (CV) or, for TDT, the standard deviation of mean values. In the study, CVs obtained for single-chemical and mixture toxicity endpoints (EC25, EC50, and EC75) at each exposure time were <20, as were those for the predicted DA and I curves. For the MX/DA metric, mixture toxicity was consistent with that predicted for DA at each exposure time in each experiment with CVs <6, despite some substantial variation in TDT for MC-alone at the EC25 and for the 30 to 45-min time-interval. There was lower variation in TDT for 3C2B and for MX. Mean and CV values for 5PL-1P-derived slope and asymmetry parameters were also assessed to provide bases for comparisons in future reports.

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Section: Discussionsupporting

confidence: 75%

Evaluation of consistency for multiple experiments of a single combination in the time-dependence mixture toxicity assay

Dawson

Pöch

2017

Toxicology Mechanisms and Methods

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“…Other investigations based on Biolog plates come to a comparable coefficient of variation for different soil nutrient amendments (42% in a laboratory experiment with sulfachloropyridazine [27] or 16‐55% at different field sites that were not contaminated with metals [12]). Overall, the variation is in the range as observed for intralaboratory variation in other complex ecotoxicological test systems [28,29]. Although a coefficient of variation of smaller than 30% is generally aimed at, this criterion is frequently exceeded in test systems with difficult environmental media such as soil, with difficult polar and degrading test substances, and with non‐standardized communities in place of single standardized test species.…”

Section: Discussionmentioning

confidence: 99%

On the limits of toxicant-induced tolerance testing: Cotolerance and response variation of antibiotic effects

Schmitt¹,

Martinali²,

Beelen³

et al. 2006

Environmental Toxicology and Chemistry

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Pollution-induced community tolerance (PICT) as an ecotoxicological test system has been claimed to detect pollutant effects highly specifically and sensitively. However, the specificity might be limited by the occurrence of cotolerance. Another limitation of the application of any ecotoxicological test system lies in variation of the measured responses. We tested the variation and the occurrence of cotolerance experimentally, using antibiotics as toxicants, soil microcosms as microbial communities, and tolerance determination in Biolog plates as PICT detection test. Bacteria have been discussed as being prone to multiple tolerances due to the possible accumulation of multiple resistance genes on mobile genetic elements. However, in our experiments, cotolerance occurred only between antibiotics of the same group (oxytetracycline and tetracycline), as expected from their identical mode of action. Cotolerance between oxytetracycline and tylosin in soil microcosms exposed to oxytetracycline was low, as was cotolerance to oxytetracycline in tylosin-exposed microcosms. We conclude that tolerance development to antibiotics in soils reflects the actual selection pressure rather than a general pattern of multiple resistances. Concerning variation, the PICT effect of tetracycline was well reproducible in two consecutive years. The response variation linked to PICT experiments in controlled microcosms was comparable to that of ecotoxicological test systems of equivalent complexity. In conclusion, our results support an application of the PICT methodology as an effective means to study the soil ecotoxicology of antibiotics.

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“…The CVs for each sample were lower than those calculated in the original standard volume A. abdita round‐robin from Schlekat et al [19] (Table 6). Interlaboratory variability can arise because of differing source organisms, laboratory conditions, and analyst experience [25]. Detailed protocols were used in this study and Schlekat et al [19].…”

Section: Discussionmentioning

confidence: 99%

Interlaboratory comparison of a reduced volume marine sediment toxicity test method using the amphipodAmpelisca abdita

Ferretti

Calesso

Lazorchak

et al. 2004

Enviro Toxic and Chemistry

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The U.S. Environmental Protection Agency has standardized methods for performing acute marine amphipod sediment toxicity tests. A test design reducing sediment volume from 200 to 50 ml and overlying water from 600 to 150 ml was recently proposed. An interlaboratory comparison was conducted to evaluate the precision of this reduced sediment volume toxicity test method using the marine amphipod Ampelisca abdita. A negative control and three sediment samples of varying degrees of toxicity ranging from low to high were tested by six laboratories. Complete agreement was reached in rank of relative toxicity for all samples tested by five out of six laboratories. Test acceptability for control survival was achieved by all laboratories, and 69% agreement in classification of the sediments as toxic or nontoxic was documented. Coefficients of variation in all test samples were similar to those reported in other interlaboratory studies using marine amphipods. Results of this study indicate that the reduced sediment volume test using A. abdita is a reliable and precise measure of acute toxicity in marine sediment samples.

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Intra‐ and intertreatment variability in reference toxicant tests: Implications for whole effluent toxicity testing programs

Cited by 22 publications

References 12 publications

Evaluation of consistency for multiple experiments of a single combination in the time-dependence mixture toxicity assay

Evaluation of consistency for multiple experiments of a single combination in the time-dependence mixture toxicity assay

On the limits of toxicant-induced tolerance testing: Cotolerance and response variation of antibiotic effects

Interlaboratory comparison of a reduced volume marine sediment toxicity test method using the amphipodAmpelisca abdita

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