Chronic toxicity of pulse‐dosed fenoxycarb to<i>Daphnia magna</i>exposed to environmentally realistic concentrations

Hosmer, Alan J.; Warren, Laurie W.; Ward, Timothy J.

doi:10.1002/etc.5620170929

Cited by 64 publications

(1 citation statement)

References 33 publications

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“…3,[66][67][68][69][70][71] Very little is known about the effects of short but high peaks of toxicants and how intermittent phases with low or negligible concentrations allow recovery. Consequences of time-varying or repeated exposure may include cumulative effects of pulses, 36,44,46,[72][73][74][75] post-exposure effects, [76][77][78][79] recovery between pulses, [80][81][82][83] and other patterns, 3,18,84 some of which depend on the mode of action. 85 These phenomena can in principle be explained and simulated by TK-TD models.…”

Section: Fluctuating and Pulsed Exposure And Resulting Effect Patternsmentioning

confidence: 99%

Advantages of toxicokinetic and toxicodynamic modelling in aquatic ecotoxicology and risk assessment

2010

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Toxicokinetic-toxicodynamic (TK-TD) models simulate the processes that lead to toxicity at the level of organisms over time. These dynamic simulation models quantify toxicity, but more importantly they also provide a conceptual framework to better understand the causes for variability in different species' sensitivity to the same compound as well as causes for different toxicity of different compounds to the same species. Thus TK-TD models bring advantages for very diverse ecotoxicological questions as they can address two major challenges: the large number of species that are potentially affected and the large number of chemicals of concern. The first important benefit of TK-TD models is the role that they can play to formalize established knowledge about toxicity of compounds, sensitivity of organisms, organism recovery times and carry-over toxicity. The second important aspect of TK-TD models is their ability to simulate temporal aspects of toxicity which makes them excellent extrapolation tools for risk assessment of fluctuating or pulsed exposures to pollutants. We provide a general introduction to the concept of TK-TD modelling for environmental scientists and discuss opportunities as well as current limitations.

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Section: Fluctuating and Pulsed Exposure And Resulting Effect Patternsmentioning

confidence: 99%

Advantages of toxicokinetic and toxicodynamic modelling in aquatic ecotoxicology and risk assessment

2010

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Review of toxicological effects caused by episodic stressor exposure

Gordon

Mantel

Muller³

2012

Enviro Toxic and Chemistry

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Water quality monitoring tools that rely on data from stress-response tests with continuous exposure at constant concentrations are not always appropriately protective when stressor exposure in the field is episodic in nature. The present study identifies various approaches that have attempted to account for episodic stressor exposure, describes the development of a toxicological effects database of episodic stressor exposure collated from published scientific literature, and discusses whether any discernible trends are evident when these data are reviewed. The episodic stressor exposure literature indicated that few generalizations can be made regarding associated biological responses. Instead, when attempting to characterize the hazard of a certain episodic pollution event, the following situation-specific information is required: the specific species affected and its age, the specific stressor and its concentration, the number of exposures to the stressor, the duration of exposure to the stressor, and the recovery time after each exposure. The present study identifies four main challenges to the inclusion of episodic toxicity data in environmental water quality management: varying stressor concentration profiles, defining episodic stressor concentration levels, variation resulting from routes of exposure and modes of action, and species-specific responses to episodic stressor exposure. The database, available at http://iwr.ru.ac.za/iwr/download, could be particularly useful for site-specific risk assessments related to episodic exposures.

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Development of short, acute exposure hazard estimates: A tool for assessing the effects of chemical spills in aquatic environments

Bejarano¹,

Farr

2013

Enviro Toxic and Chemistry

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Management decisions aimed at protecting aquatic resources following accidental chemical spills into rivers and coastal estuaries require estimates of toxic thresholds derived from realistic spill conditions: acute pulse exposures of short duration (h), information which often is unavailable. Most existing toxicity data (median lethal concentration or median effective concentration) come from tests performed under constant exposure concentrations and exposure durations in the 24-h to 96-h range, conditions not typical of most chemical spills. Short-exposure hazard concentration estimates were derived for selected chemicals using empirical toxicity data. Chemical-specific 5th percentile hazard concentrations (HC5) of species sensitivity distributions (SSD) from individual exposure durations (6-96 h) were derived via bootstrap resampling and were plotted against their original exposure durations to estimate HC5s and 95% confidence intervals (CIs) at shorter exposures (1, 2, and 4 h). This approach allowed the development of short-exposure HC5s for 12 chemicals. Model verification showed agreement between observed and estimated short-exposure HC5s (r(2) adjusted = 0.95, p < 0.0001), and comparison of estimated short-exposure HC5s with empirical toxicity data indicated generally conservative hazard estimates. This approach, applied to 2 real spill incidents, indicated hazard estimates above expected environmental concentrations (acrylonitrile), and suggested that environmental concentrations likely exceeded short-exposure hazard estimates (furfural). Although estimates generated through this approach were likely overprotective, these were derived from environmentally realistic exposure durations, providing risk-assessors with a tool to manage field decisions. Environ Toxicol Chem 2013;32:1918-1927. © 2013 SETAC.

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Chronic toxicity of pulse‐dosed fenoxycarb toDaphnia magnaexposed to environmentally realistic concentrations

Cited by 64 publications

References 33 publications

Advantages of toxicokinetic and toxicodynamic modelling in aquatic ecotoxicology and risk assessment

Advantages of toxicokinetic and toxicodynamic modelling in aquatic ecotoxicology and risk assessment

Review of toxicological effects caused by episodic stressor exposure

Development of short, acute exposure hazard estimates: A tool for assessing the effects of chemical spills in aquatic environments

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