Sensitivity and response time of three common Antarctic marine copepods to metal exposure

Enviro Toxic and Chemistry

Harrison

2017

Self Cite

Toxicity testing with Antarctic species is required for risk assessment of fuel spills in Antarctic coastal waters. The lethal and sublethal (movement behavior) sensitivities of adults and juveniles of the Antarctic amphipod Paramoera walkeri to the water accommodated fractions (WAFs) of 3 fuels were estimated in extended-duration tests at -1 °C to 21 d. Response of P. walkeri for lethal hydrocarbon concentrations was slow, with 50% lethal concentrations (LC50s) first able to be estimated at 7 d for adults exposed to Special Antarctic Blend diesel (SAB), which had the highest hydrocarbon concentrations of the 3 fuel WAFs. Juveniles showed greater response to marine gas oil (MGO) and intermediate residual fuel oil (IFO 180) at longer exposure durations and were most sensitive at 21 d to IFO 180 (LC50 = 12 μg/L). Adults were initially more sensitive than juveniles; at 21 d, however, juveniles were more than twice as sensitive as adults to SAB (LC50 = 153 μg/L and 377 μg/L, respectively). Significant effects on movement behavior were evident at earlier time points and lower concentrations than was mortality in all 3 fuel WAFs, and juveniles were highly sensitive to sublethal effects of MGO. These first estimates of Antarctic amphipod sensitivity to diesel and fuel oils in seawater contribute to the development of ecologically relevant risk assessments for management of hydrocarbon contamination in the region. Environ Toxicol Chem 2017;36:2444-2455. © 2017 SETAC.

Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Lethal and behavioral impacts of diesel and fuel oil on the Antarctic amphipodParamoera walkeri

Brown

Enviro Toxic and Chemistry

Harrison

2017

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“…Confidence in estimates also increased over time as indicated by the narrowing of 95% CIs from 21 to 28 d (Table ). The slow response time of P. murrayi to Cu is similar to that observed for many Antarctic marine invertebrates, in which response to metals is delayed compared to temperate and tropical species (King and Riddle ; Marcus Zamora et al ; Sfiligoj et al ). The delayed response to contaminants can be attributed to physiological characteristics of Antarctic species, such as slow metabolic rate, extended developmental times, and long life cycles, as well as to the retardation of chemical reactions in the cold (Chapman and Riddle ).…”

Section: Resultssupporting

confidence: 71%

Sensitivity to Copper and Development of Culturing and Toxicity Test Procedures for the Antarctic Terrestrial Nematode Plectus murrayi

Brown

Wasley

Enviro Toxic and Chemistry

2020

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Environmental quality guideline values and remediation targets, specific to Antarctic ecosystems, are required for the risk assessment and remediation of contaminated sites in Antarctica. Ecotoxicological testing with Antarctic soil organisms is fundamental in determining reliable contaminant effect threshold concentrations. The present study describes the development of optimal culturing techniques and aqueous toxicity test procedures for an endemic Antarctic soil nematode, Plectus murrayi, which lives within interstitial waters between soil particles. Toxicity tests were of extended duration to account for the species' physiology and life-history characteristics. Plectus murrayi was sensitive to aqueous copper with a 50% effective concentration for egg-hatching success of 139 µg/L. Hatched juveniles that were first exposed to copper as eggs appeared to be less sensitive than those first exposed at the hatched J2 stage, indicating a potential protective effect of the egg. Sensitivity of juveniles to copper increased with exposure duration, with 50% lethal concentrations of 478 and 117 µg/L at 21 and 28 d, respectively. The present study describes new methods for the application of an environmentally relevant test species to the risk assessment of contaminants in Antarctic soil and provides the first estimates of sensitivity to a toxicant for an Antarctic terrestrial microinvertebrate. Environ Toxicol Chem 2020;39:482-491. © 2019 SETAC

“…To better understand how contaminants affect the Antarctic marine ecosystem, recent research has developed toxicity test protocols for a range of Antarctic and subantarctic organisms (Duquesne and Liess, 2003;Gissi et al, 2015;Hill et al, 2009;Holan et al, 2016;King and Riddle, 2001; Lewis et al, 2016;Marcus Zamora et al, 2015;Runcie and Riddle, 2007;Sfiligoj et al, 2015). These studies have only investigated the toxic response of organisms to single contaminants, and do not assess interactive effects of mixtures, as would be found in the Antarctic marine environment.…”

Section: Introductionmentioning

confidence: 99%

Chronic toxicity of an environmentally relevant and equitoxic ratio of five metals to two Antarctic marine microalgae shows complex mixture interactivity

Koppel

Adams

Environmental Pollution

et al. 2018

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Metal contaminants are rarely present in the environment individually, yet environmental quality guidelines are derived from single-metal toxicity data. Few metal mixture studies have investigated more than binary mixtures and many are at unrealistically high effect concentrations to freshwater organisms. This study investigates the toxicity of five metals (Cd, Cu, Ni, Pb, and Zn) to the Antarctic marine microalgae Phaeocystis antarctica and Cryothecomonas armigera. Two mixtures were tested: (i) an equitoxic mixture of contaminants present at their single-metal EC10 concentrations, and (ii) an environmental mixture based on the ratio metal concentrations in a contaminated Antarctic marine bay. Observed toxicity, as chronic population growth rate inhibition, was compared to Independent Action (IA) and Concentration Addition (CA) predictions parameterised to use EC10 values. This allowed for the inclusion of metals with low toxicities. The biomarkers chlorophyll a fluorescence, cell size and complexity, and intracellular lipid concentrations were assessed to investigate possible mechanisms behind metal-mixture interactions. Both microalgae had similar responses to the equitoxic mixture: non-interactive by IA and antagonistic by CA. Toxicity from the environmental mixture was antagonistic by IA to P. antarctica; however, to C. armigera it was concentration-dependent with antagonism at low toxicities and synergism at high toxicities by both IA and CA. Differences in dissolved organic carbon production and detoxification mechanisms may be responsible for these responses and warrants further investigation. This study shows that mixture toxicity interactions can be ratio, species, and concentration dependent. The responses of the microalgae to different mixture ratios highlight the need to assess toxicity at environmentally realistic metal ratios. Parameterising IA and CA reference models to use EC10s allowed for the inclusion of metals at low effect concentrations, which may otherwise be ignored. Reference mixture models are generally suitable for predicting chronic toxicity of metals to these marine microalgae at environmentally realistic ratios and concentrations.