A statistical procedure for modeling continuous toxicity data

Bruce, Robert D.; Versteeg, Donald J.

doi:10.1002/etc.5620111014

Cited by 117 publications

(63 citation statements)

References 11 publications

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“…Post-ANOVA nonlinear regression analyses were used to calculate the inhibitory concentration of a herbicide associated with a 25% reduction in plant response (IC25, calculated as effective concentration based on Bruce and Versteeg [24] and further redefined as IC based on USEPA [1]). The regression analysis used the calculated concentrations of 0, 0.001, 0.002, 0.01, 0.1, and 1.0 (if present) Â the field application rate for the herbicide concentrations.…”

Section: Discussionmentioning

confidence: 99%

Effects of low levels of herbicides on prairie species of the Willamette Valley, Oregon

Olszyk

Blakeley-Smith²,

Pfleeger³

et al. 2013

Enviro Toxic and Chemistry

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The relative sensitivity of 17 noncrop plant species from Oregon's Willamette Valley was determined in response to glyphosate, tribenuron methyl (tribenuron), and fluazifop-p-butyl (fluazifop) herbicides. For glyphosate, Elymus trachycaulus, Festuca arundinacea, Madia elegans, Potentilla gracilis, and Ranunculus occidentalis were the most sensitive species, based on a concentration calculated to reduce shoot dry weight by 25% (IC25 values) of 0.02 to 0.04 × a field application rate of 1112 g active ingredient (a.i.) per hectare. Clarkia amoena and Lupinus albicaulis were the most tolerant to glyphosate, with IC25 values near the field application rate. Clarkia amoena, Prunella vulgaris, and R. occidentalis were the most sensitive to tribenuron, with IC25 values of 0.001 to 0.004 × a field application rate of 8.7 g a.i. ha(-1) for shoot dry weight. Five grass species were tolerant to tribenuron with no significant IC25 values. For fluazifop, 2 native grasses, E. trachycaulus and Danthonia californica, were the most sensitive species, with IC25 values of 0.007 and 0.010 × a field application rate of 210 g a.i. ha(-1) , respectively, for shoot dry weight, while a native grass, Festuca roemeri, and nearly all forbs showed little or no response. These results also indicated that the 3 introduced species used in the present study may be controlled with 1 of the tested herbicides: glyphosate (F. arundinacea), tribenuron (Leucanthemum vulgare), and fluazifop (Cynosurus echinatus).

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Section: Discussionmentioning

confidence: 99%

Effects of low levels of herbicides on prairie species of the Willamette Valley, Oregon

Olszyk

Blakeley-Smith²,

Pfleeger³

et al. 2013

Enviro Toxic and Chemistry

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“…Application of the jackknife procedure [17] for estimates of fitness resulted in pseudovalues, which were analyzed by Dunnett's test. The EC20 value for reproduction was estimated using nonlinear regression procedures as described in Bruce and Versteeg [18]. All Dunnett's tests were performed with ␣ ϭ 0.05.…”

Section: Discussionmentioning

confidence: 99%

“…The left-hand side of the graph shows the relationship between a proportional decrease in n t and changes in fitness for the two nematode species. The right-hand side shows the plasticity of n t to copper and was simulated using toxicity data according to Bruce and Versteeg [18].…”

Section: Relating Plasticity In Reproduction To Fitnessmentioning

confidence: 99%

“…The left-hand side of the graph shows the relationship between a proportional decrease in n t and impairment of fitness. The right-hand side of the graph shows the simulated plasticity of n t to copper for P. acuminatus and H. pauciannulatus using the method of Bruce and Versteeg [18] based on life-cycle toxicity data.…”

Section: Relating Plasticity In Reproduction To Fitnessmentioning

confidence: 99%

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Comparing differences in species sensitivity to toxicants: Phenotypic plasticity versus concentration‐response relationships

Kammenga

Riksen

1996

Enviro Toxic and Chemistry

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The comparison of species sensitivity to toxicants is classically derived from differences in the concentration‐response relationships of a sensitive trait such as reproduction. We tested this general concept by conceiving the concentration‐response relationship as a plastic response to a range of discrete environments. Using a demographic model based on life‐cycle experiments for two nematode species (Plectus acuminatus and Heterocephalobus pauciannulatus) we related copper‐induced plasticity in reproduction to changes in fitness, which was defined as the population growth rate. Daily reproduction (nt) in P. acuminatus was more sensitive to copper (EC20 = 48 μM) than in H. pauciannulatus (EC20 =138 μM). However, the relationship between plasticity in nt and fitness showed that for both species, fitness was reduced with 5%. These findings imply that P. acuminatus and H. pauciannulatus are equally susceptible to toxicant‐induced changes in nt despite their differences in EC20 values for reproduction. It may be concluded that differences in susceptibility of species to toxicants are not only determined by the effect on sensitive traits but also by the relationship between plasticity in this trait and fitness.

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“…The influence of temperature, pH, and soil moisture content on the ratio was analyzed by analysis of variance. The EC50 values were estimated using nonlinear regression procedures as described in Bruce and Versteeg [20]. No-observedeffect concentration (NOEC) values were determined using Student's t-test.…”

Section: Discussionmentioning

confidence: 99%

A Toxicity Test in Artificial Soil Based on the Life-History Strategy of the Nematode Plectus Acuminatus

Kammenga¹,

Koert²,

Riksen³

et al. 1996

Environ Toxicol Chem

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Abstract-The ecological risk assessment of toxicants in soil requires reproducible and relevant test systems using a wide range of species. To supplement present test methods from the Organisation of Economic Cooperation and Development (OECD) in artificial soil with earthworms and springtails, a toxicity test in OECD artificial soil has been developed using the bacterivorous nematode Plectus acuminatus (Bastian, 1865) (Nematoda; Plectidae). The juvenile to adult ratio was used as a test parameter since previous life-cycle studies pointed out that fitness of P. acuminatus was strongly determined by changes in both reproduction and juvenile survival. Optimal conditions for the performance of nematodes in OECD artificial soil were determined (pH KCl ϭ 5.5, temperature ϭ 20ЊC, and a moisture content of 70% dry wt. artificial soil), and tests were conducted with cadmium, copper, and pentachlorophenol. After an exposure period of 3 weeks the EC50 for cadmium was 321.0 Ϯ 1.7 mg/kg dry wt., and the no-observed-effect concentration (NOEC) was 32 mg/kg dry wt. The EC50 for pentachlorophenol was 47.9 Ϯ 1.2 mg/kg dry wt., and the NOEC was Ͻ10 mg/kg dry wt. For copper the EC50 was 162 Ϯ 0.2 mg/kg dry wt., and the NOEC was 32 mg/kg dry wt. It is concluded that the nematode test may well supplement current soil test systems using earthworms and springtails.

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A statistical procedure for modeling continuous toxicity data

Cited by 117 publications

References 11 publications

Effects of low levels of herbicides on prairie species of the Willamette Valley, Oregon

Effects of low levels of herbicides on prairie species of the Willamette Valley, Oregon

Comparing differences in species sensitivity to toxicants: Phenotypic plasticity versus concentration‐response relationships

A Toxicity Test in Artificial Soil Based on the Life-History Strategy of the Nematode Plectus Acuminatus

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