Single metal and metal mixture toxicity of five metals to Oppia nitens in five different Canadian soils

Jegede, Olugbemiro J.; Awuah, Kobby Fred; Renaud, Mathieu; Cousins, Mark; Hale, Beverley; Siciliano, Steven D.

doi:10.1016/j.jhazmat.2020.122341

Cited by 8 publications

(3 citation statements)

References 40 publications

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“…The other uncertainty is whether these conclusions would be valid for higher values of EC (e.g., 25%–50% reduction in the endpoint), something that could not be explored in the present study because field observations of toxicity at these sites did not reveal large losses of ecological function. This would be a worthwhile investigation because it is known that mode of toxic action might be different at higher toxicity thresholds (Nys et al 2015; Jegede et al 2020).…”

Section: Resultsmentioning

confidence: 99%

Is assuming additivity of single‐metal toxicity thresholds a conservative approach to assessing risk of ecotoxicity from elevated soil concentrations of cobalt, copper, and nickel at contaminated sites?

Gopalapillai

Siciliano

Hale

2021

Integr Envir Assess & Manag

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Multiple metal‐impacted soils are often realistic scenarios for risk assessments, but tools to address these are currently lacking. The objective of this work was to evaluate whether assuming concentration addition (CA) of metal mixture effects was conservative for prospective risk assessment of soils that were elevated mainly in Ni and Cu and somewhat with Co, Pb, or As. Observed whole mixture toxicity for field soils with aged metal mixtures was compared to the expected whole mixture toxicity, assuming additivity of prospective single‐metal thresholds (“toxic units”) for the mixture components. Bioavailability‐adjusted single‐metal toxicity thresholds expected for those field soils were the median hazard concentration affecting 5% of species (HC5‐50) from the predicted no‐effect concentration (PNEC) calculator and calculated from the species‐specific dose–response multiple linear relationships (MLRs), all from the European Union Registration, Evaluation, Authorisation and Restriction of Chemicals (EU REACH) dossiers for metals. Generic single‐metal toxicity thresholds were based on Canadian Council of Ministers of the Environment soil quality guidelines (CCME SQGs) for agricultural soils. Observed toxicity thresholds were from the community‐based risk assessments conducted for Port Colborne and Sudbury, Ontario, Canada. Mostly, prospective single‐metal toxicity thresholds were protective relative to the observed toxicity, although that was species or ecological process dependent. The bioavailability‐adjusted single‐metal thresholds were less conservative than the CCME SQG method, even though the former is based on site‐specific EC10 values, and the latter is based on generic EC25 values. When within‐site variability in soil properties was used to calculate the 5th and 95th CI for the HC5 sum of toxic units (∑TUs), CA was conservative for far fewer endpoints. In addition, the prospective ∑TUs were more conservative predictions of the observed whole mixture toxicities for Port Colborne soils than for Sudbury soils. The most appropriate balance of accuracy and conservatism for identifying low‐level risk of the whole mixtures in these soils appeared to be the bioavailability‐adjusted HC5‐50, which was applicable to many endpoints and 2 quite different exposure concentration ratios. Integr Environ Assess Manag 2021;17:753–766. © 2020 SETAC

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Section: Resultsmentioning

confidence: 99%

Is assuming additivity of single‐metal toxicity thresholds a conservative approach to assessing risk of ecotoxicity from elevated soil concentrations of cobalt, copper, and nickel at contaminated sites?

Gopalapillai

Siciliano

Hale

2021

Integr Envir Assess & Manag

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“…The equivalent-effect concentration ratio (EECR), specified proportion, − and fixed proportion − are commonly used by most of the scholars when designing mixtures. For example, Zhao et al .…”

Section: Introductionmentioning

confidence: 99%

Study on the Combined Toxicities and Quantitative Characterization of Toxicity Sensitivities of Three Flavor Chemicals and Their Mixtures to Caenorhabditis elegans

et al. 2021

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It was shown that flavor chemicals with high toxicity sensitivities mean that small changes in their effective concentrations can lead to significant changes in toxicity. Flavors are widely used in personal care products. However, our study demonstrated that some flavor chemicals and their mixture rays have high toxicity sensitivities to Caenorhabditis elegans ( C. elegans ), which may have an impact on human health. In this paper, three flavor chemicals (benzyl alcohol, phenethyl alcohol, and cinnamaldehyde) were used as components of the mixture, and three binary mixture systems were constructed, respectively. Five mixture rays were designed for each mixture system by a direct equipartition ray design method. The lethal toxicities of the three flavor chemicals and mixture rays to C. elegans at three exposure volumes were determined. A new concept (inverse of the negative logarithmic concentration span (iSPAN)) was introduced to quantitatively evaluate the toxicity sensitivity of chemicals or mixture rays, and the combination index (CI) was employed to identify the toxicological interactions in the mixtures. It was shown that the three flavor chemicals as well as the binary mixture rays have a significant concentration–response relationship on the lethality of C. elegans . The iSPAN values of the three flavor chemicals and their mixture rays were larger than 3.000, showing very strong toxicity sensitivity to C. elegans . In mixture systems, the toxicity sensitivities of mixture rays with different mixture ratios were also different at different exposure volumes. In addition, it can be seen from the CI heat map that the toxicological interaction not only shows the mixture ratio dependence but also changes with the different exposure volumes, which implies that the mixtures consisting of flavor chemicals with high toxicity sensitivity have complex toxicological interactions. Therefore, in environmental risk assessment, special attention should be paid to chemicals with high toxicity sensitivities.

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“…However, identifying the modes of action for different chemicals is not always possible. In those cases, CA is suggested to be the more conservative choice in a risk assessment context as it estimates higher toxic effects than IA and therefore represents the worst-case scenario for assessing mixture exposures (Backhaus & Faust, 2012;Cremazy et al, 2018;Gopalapillai & Hale, 2017;Jegede et al, 2020;Lock & Janssen, 2002;Nys et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Incorporation of chemical and toxicological availability into metal mixture toxicity modeling: State of the art and future perspectives

Gong

Qiu

Romero‐Freire

et al. 2020

Critical Reviews in Environmental Science and Technology

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Single metal and metal mixture toxicity of five metals to Oppia nitens in five different Canadian soils

Cited by 8 publications

References 40 publications

Is assuming additivity of single‐metal toxicity thresholds a conservative approach to assessing risk of ecotoxicity from elevated soil concentrations of cobalt, copper, and nickel at contaminated sites?

Is assuming additivity of single‐metal toxicity thresholds a conservative approach to assessing risk of ecotoxicity from elevated soil concentrations of cobalt, copper, and nickel at contaminated sites?

Study on the Combined Toxicities and Quantitative Characterization of Toxicity Sensitivities of Three Flavor Chemicals and Their Mixtures to Caenorhabditis elegans

Incorporation of chemical and toxicological availability into metal mixture toxicity modeling: State of the art and future perspectives

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