Predicting chronic algal toxicity from 1- to 48-h pulsed exposures to mine site waters using time-averaged concentrations

Angel, Brad M.; Figuière, Romain; Simpson, Stuart L.

doi:10.1016/j.ecoenv.2020.110263

Cited by 9 publications

(7 citation statements)

References 28 publications

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“…Many water quality risk assessment tools, including the application of water quality guideline values and direct toxicity assessment methods, are designed to predict the risk of toxicity from continuous contaminant exposures (Warne et al, 2018). A growing body of literature indicates that when one is evaluating the toxicity of contaminants in the aquatic environment, the testing conditions, exposure duration, and exposure frequency are as critical as the exposure concentration (Angel et al, 2020; Diamond et al, 2006; Gordon et al, 2012; Hoang et al, 2007; Mehler et al, 2020; Rosen et al, 2019). Generally, it is assumed that as the net‐exposure‐dose increases (concentration × duration), the toxicity of the contaminant increases and toxicity may be comparable based on a time‐weighted average concentration (TAC; Angel et al, 2015; Gordon et al, 2012; Mancini, 1983).…”

Section: Introductionmentioning

confidence: 99%

“…This may be dependent on species‐ and endpoint‐specific modes of toxicity, which will be influenced by rates of uptake and depuration, contaminant transportation, and metabolism (Hoang et al, 2007a, 2007b, 2007c; Hogan et al, 2013; Naddy et al, 2000). Improved single‐contaminant pulse exposure toxicity data for a broader range of chemicals, organisms, and effects endpoints may enable development of models that can more accurately predict environmentally realistic pulse exposure effects (Angel et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Pulse‐Exposure Toxicity of Ammonia and Propoxur to the Tropical Copepod Acartia sinjiensis

Stone

Koppel

Binet

et al. 2021

Enviro Toxic and Chemistry

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Toxicity risk assessments of short-term discharges of contaminated waters to the aquatic environment have shown that receptor organisms can tolerate higher pulse-exposure than continuous-exposure concentrations of some contaminants. However, these observations are influenced by the mode of toxicity of the contaminants present and the concentration-time profile of the exposure. For common metal contaminants, the time-weighted average concentration (TAC) of the exposure has been useful for predicting risk of toxicity to multiple species, including the tropical, euryhaline copepod Acartia sinjiensis. To increase our understanding of the application and limitations of the TAC approach, the present study examined how varied pulse-exposure durations affect the toxicity of fast-acting contaminants, ammonia, and the common pesticide propoxur to this copepod species. Copepod larvae were exposed under continuous-exposure conditions (all life stages from eggs to nauplii to copepodites exposed) and as 6-and 18-h pulse exposures applied during the most sensitive life stage only (24-h-old nauplii) within 78-h tests. Larval development ratio and population size were assessed as test endpoints. Generally, increased exposure duration resulted in increased toxicity. Trends observed for ammonia and propoxur were slightly different for larval development and population size. Larvae tolerated greater concentrations of contaminants in a 6-h pulse (higher 10% effect concentration) than in an 18-h pulse, or a continuous 78-h exposure, whereas toxicity responses converged for the 18-and 78-h exposures. Continuous toxicity thresholds were always protective of pulse exposures, providing a conservative toxicity threshold for all durations of pulse exposures. Although generalizations for predictions of risk based on TACs are frequently effective for common metal contaminants, the TAC approach was not effective for ammonia and propoxur.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pulse‐Exposure Toxicity of Ammonia and Propoxur to the Tropical Copepod Acartia sinjiensis

Stone

Koppel

Binet

et al. 2021

Enviro Toxic and Chemistry

Self Cite

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“…Direct toxicity assessments are of the highest environmental relevance because they assess all interactions among contaminants, physicochemical properties, and water and soil phases, thereby combining the effect of all stressors present in a sample as a combined exposure. Direct toxicity assessments are regularly used in the assessment of industrial sites such as mines (e.g., Trenfield et al 2019 ; Angel et al 2020 ), groundwater at fuel release sites (e.g., Patterson et al 2020 ), and contaminated groundwater discharge into waterways (e.g., Hunt et al 2009 ) to determine the appropriate dilution of discharges and to derive site‐specific guidelines.…”

Section: Introductionmentioning

confidence: 99%

Using an expert judgment response matrix to assess the risk of groundwater discharges from remediated fuel spill sites to the marine environment at sub‐Antarctic Macquarie Island, Australia

King

Wasley

Holan

et al. 2021

Integr Envir Assess & Manag

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This study assesses toxicity of groundwater from remediated fuel spill sites, as the final phase of an environmental risk assessment of contaminated sites at sub‐Antarctic Macquarie Island, Tasmania, Australia. To complement previous terrestrial ecotoxicological research, we determine risk to marine environments from residual biodegraded hydrocarbon contaminants in groundwater discharges. Direct toxicity assessments were conducted on 7 composite groundwater test solutions, adjusted to ambient seawater salinity. Eleven native marine invertebrates (from varied taxa: gastropods, bivalves, flatworms, amphipods, copepods, isopods) were exposed and observed for up to 21 d. Lethal time estimates (LT10, LT50) showed sensitivity was time dependent (LT10s = 4–15 d) and variable between species. Three species showed no response to any test solution, and most species did not respond for up to 5 d. Data were interpreted using an expert judgment response matrix with multiple lines of evidence to predict risk. No consistent patterns in the relative toxicity of test solutions, based on polar or nonpolar hydrocarbon concentrations, were identified. Although toxicity was observed in some species, this was only under worst‐case conditions of undiluted, continuous, extended exposure. Natural dynamics of the site, including low groundwater discharge rates, high rainfall, and a highly energetic receiving environment, ensure groundwater is rapidly diluted and dispersed. In this context, and based on site conditions at the time of testing, these toxicity assessments provide robust evidence that residual contamination in groundwater at remediated sites at Macquarie Island is unlikely to represent a risk to the adjacent marine communities tested. Integr Environ Assess Manag 2021;17:785–801. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

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“…This can be achieved by comparing the time-averaged concentration (TAC), a measurement of the net dose an organism receives over a given time, to WQGs derived from continuous exposures. Generally, TACs have been found to be good predictors of metal toxicity regardless of the pulse exposure regime (i.e., pulse duration, frequency) for a number of metal contaminants and a range of aquatic organisms (Angel et al, 2020). However, comparison of TACs to the predicted toxic response can be complicated by a range of factors, for example, species-specific regulatory abilities, pulse exposure frequency, and the effect of complex and temporally dynamic mixtures.…”

mentioning

confidence: 99%

“…The use of metal mixtures in pulse exposures needs to account for additive (synergistic) or nonadditive (antagonistic) toxicity between different metals, as well as the effect of ligands such as sulfate. The TAC approach shows promise in predicting the toxicity of pulse exposures of complex metal mixtures (Angel et al, 2020), albeit for different effluents (treated mine wastewater). Further work is required in this area to better understand the acute and chronic effects associated with waters that contain temporally dynamic and complex mixtures of contaminants with different modes of action.…”

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confidence: 99%

Water Quality Guidelines for Metal Contaminants in Stormwater Runoff: Insights and Considerations

McDonald

2021

Enviro Toxic and Chemistry

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Stormwater runoff can result in significant temporal fluctuations in the concentration of metal contaminants in receiving waterways. The quality of stormwater runoff during rainfall events can be highly degraded with metal concentrations that may exceed toxicity thresholds. Metals in storm water can be present in a range of different forms, with the partitioning of these forms controlled by a variety of factors that display strong interstorm variability. Of particular importance are metals that exist in a bioavailable form, which is influenced by lability from dissolved complexes, colloidal and particulate forms. As a result, resident aquatic organisms in these environments are exposed to pulses of metal contaminants at high concentrations and short-term changes in physicochemical conditions.Water quality guidelines (WQGs) are often used to interpret the results of stormwater runoff quality analyses and identify key problematic pollutants. In most jurisdictions, WQGs are generated using species sensitivity distributions of toxic effect data obtained from laboratory-based tests (Australia and New Zealand Governments, 2018) where organisms are usually exposed to highly labile metals in solution (e.g., free metal ions or weakly bound complexes). When applying guideline values, it is appropriate to make comparisons to the measured concentration of labile metal forms. In the context of stormwater runoff, these WQGs may not provide environmentally relevant assessments. Specifically, WQGs will generally achieve overly conservative outcomes because organisms can typically tolerate high metal concentrations for shorter exposure durations, and only a fraction of the total metal concentration is available for organism uptake in natural systems because of ligand binding.The current need for WQGs for short-term "pulsed" contaminant discharges like stormwater runoff is an issue of concern. An approach is required that will provide an adequate level of protection and prediction of risk for a variety of

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Predicting chronic algal toxicity from 1- to 48-h pulsed exposures to mine site waters using time-averaged concentrations

Cited by 9 publications

References 28 publications

Pulse‐Exposure Toxicity of Ammonia and Propoxur to the Tropical Copepod Acartia sinjiensis

Pulse‐Exposure Toxicity of Ammonia and Propoxur to the Tropical Copepod Acartia sinjiensis

Using an expert judgment response matrix to assess the risk of groundwater discharges from remediated fuel spill sites to the marine environment at sub‐Antarctic Macquarie Island, Australia

Water Quality Guidelines for Metal Contaminants in Stormwater Runoff: Insights and Considerations

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