RESUMEN
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).
Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Regiones Antárticas , Australia , Hidrocarburos , Juicio , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidadRESUMEN
Stressors associated with climate change and contaminants, resulting from the activities of humans, are affecting organisms and ecosystems globally. Previous studies suggest that the unique characteristics of polar biota, such as slower metabolisms and growth, and the generally stable conditions in their natural environment, cause higher susceptibility to contamination and climate change than those in temperate and tropical areas. We investigated the effects of increased temperature and decreased salinity on copper toxicity in four subantarctic marine invertebrates using realistic projected conditions under a future climatic change scenario for this region. We hypothesised that these relatively subtle shifts in environmental stressors would impact the sensitivity of cold-adapted species to copper. The four test species were: a copepod Harpacticus sp.; isopod Limnoria stephenseni; flatworm Obrimoposthia ohlini; and bivalve Gaimardia trapesina. These species occupy a range of ecological niches, spanning intertidal and subtidal nearshore zones. We predicted that species would differ in their tolerance to stressors, depending on where they occurred within this ecological gradient. Organisms were exposed to the multiple stressors in a factorial design in laboratory based toxicity tests. Sensitivity estimates for copper (LC50) were calculated using a novel statistical approach which directly assessed the impacts of the multiple stressors. In three of the four species tested, sensitivity to copper was amplified by small increases in temperature (2-4⯰C). The effects of salinity were more variable but a decrease of as little as 2â¯ppt caused a significant effect in one species. This study provides some of the first evidence that high latitude species may be at increased risk from contaminants under projected future climate conditions. This interaction, between contaminants and the abiotic environment, highlights a potential pathway to biodiversity loss under a changing climate.
Asunto(s)
Organismos Acuáticos/fisiología , Cambio Climático , Cobre/toxicidad , Invertebrados/fisiología , Contaminantes Químicos del Agua/toxicidad , Animales , Regiones Antárticas , Organismos Acuáticos/efectos de los fármacos , Biota , Copépodos , Ecosistema , Invertebrados/efectos de los fármacos , Isópodos , Salinidad , Temperatura , Pruebas de ToxicidadRESUMEN
The development of environmental guidelines in the Antarctic and subantarctic is essential, because expansion of research, tourism, and fishing is placing these regions at increasing risk of contamination. Data are currently insufficient to create the region-specific guidelines needed for the unique conditions in these areas. To develop the most appropriate environmental guidelines, data from the most sensitive life stages of a species should be included to ensure effective protection throughout its life cycle. It is generally accepted that early life stages are more sensitive to contaminants. We compared the toxicity of copper between juvenile and adult life stages of 4 subantarctic marine invertebrates using sublethal and lethal endpoints. For 2 of the species tested, juveniles were more sensitive than adults. (The 7-d median effect concentration [EC50] values for the gastropod Laevilittorina caliginosa were 79 µg/L at the juvenile stage and 125 µg/L at the adult; for the flatworm Obrimoposthia ohlini, values were 190 µg/L at the juvenile stage and 300 µg/L at the adult.) For the isopod Limnoria stephenseni, juveniles were either more sensitive or of equal sensitivity to adults (7-d EC50 values: juvenile 278 µg/L and adult 320 µg/L). In contrast, for the bivalve Gaimardia trapesina, adults appeared to be more sensitive than young adults (7-d EC50 values: juvenile 23 µg/L and adult <10-20 µg/L). Although no consistent trend in the sensitivity of life history stages was observed, the present study contributes important information for the development of water quality guidelines in polar regions. Environ Toxicol Chem 2018;37:807-815. © 2017 SETAC.
Asunto(s)
Organismos Acuáticos/crecimiento & desarrollo , Cobre/toxicidad , Invertebrados/crecimiento & desarrollo , Estadios del Ciclo de Vida/efectos de los fármacos , Animales , Regiones Antárticas , Organismos Acuáticos/efectos de los fármacos , Invertebrados/efectos de los fármacos , Pruebas de Toxicidad , Contaminantes Químicos del Agua/toxicidadRESUMEN
Ecotoxicological assessments often focus on the response of an organism to an individual contaminant under standardized laboratory conditions. Under more ecologically realistic conditions, however, individuals are likely to be exposed to a range of environmental conditions that have the potential to act as additional stressors. Multiple-stressor experiments improve our understanding of an organism's response to a toxicant under ecologically relevant conditions and provide realistic risk assessment data. To date, there is no standardized method for analyzing multiple-stressor data using dose-response regression. We present a reliable technique to assess for the effects of additional stressors on an LCx estimate in a consistent framework, providing interpretable results that meaningfully deal with environmental changes and their possible impacts on sensitivity estimates to a toxicant. The method is applicable to any data set where toxicity tests are conducted at varying levels of one or more additional stressors. We illustrate the method with data from an experiment that investigates the effects of salinity and temperature on the sensitivity of the subantarctic isopod Limnoria stephenseni to copper, where it is shown that the major change in the LC50 can be primarily attributed to a specific temperature increase. This method has been incorporated into an R package available at github.com/ahproctor/LC50.
Asunto(s)
Ecotoxicología , Modelos Teóricos , Animales , Cobre/toxicidad , Isópodos , Salinidad , Temperatura , Pruebas de ToxicidadRESUMEN
Investigating the impacts of contamination on high latitude ecosystems includes determining the sensitivity of key taxa to contaminants. Unique characteristics, arising from adaption to cold and stable temperatures has likely resulted in marine biota at the poles being particularly sensitive to contamination in comparison to related species at lower latitudes. We aimed to determine the sensitivity of three species of common and ecologically important subantarctic gastropods to copper. This is the first study to investigate the sensitivity of subantarctic marine gastropods to contamination. We determined sensitivity by exposing each species to a range of copper concentrations by establishing mortality and sublethal endpoints. Sensitivity to copper was highly species specific. Laevilittorina caliginosa was relatively tolerant, with no response at Cu concentrations up to 1488µg/L following 7 d of exposure, while two species (Cantharidus capillaceus coruscans and Macquariella hamiltoni) were highly sensitive with 7 d Cu LC50 estimates of 33µg/L and 78µg/L respectively. In a global comparison of gastropod sensitivity data, these two species were highly sensitive to copper, highlighting the vulnerability of polar ecosystems to contamination.
Asunto(s)
Cobre/toxicidad , Gastrópodos/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Animales , Organismos Acuáticos/efectos de los fármacos , Regiones Árticas , EcosistemaRESUMEN
A long history of anthropogenic activities in the relatively pristine subantarctic has resulted in areas of accumulated waste and contaminants. Sensitivities to metals of subantarctic and Antarctic species may contrast with related species from temperate and tropical areas because of the unique characteristics of polar biota. In addition, response to contaminants may be delayed, and hence longer exposure periods may be required in toxicity tests with polar species. In the present study, the sensitivity of 6 common subantarctic marine invertebrates to copper, zinc, and cadmium contaminants was determined. Large variations in sensitivities, both between species and between metals within species, were found. The bivalve Gaimardia trapesina and the copepod Harpacticus sp. were the most sensitive to copper, with 7-d median lethal concentration (LC50) values for both species ranging between 28 µg/L and 62 µg/L, whereas the copepod Tigriopus angulatus was the most tolerant of copper (7-d Cu LC50 1560 µg/L). Sensitivity to zinc varied by approximately 1 order of magnitude between species (7-d LC50: 329-3057 µg/L). Sensitivity to cadmium also varied considerably between species, with 7-d LC50 values ranging from 1612 µg/L to >4383 µg/L. The present study is the first to report the sensitivity of subantarctic marine invertebrate to metals, and contributes significantly to the understanding of latitudinal gradients in the sensitivity of biota to metals. Although sensitivity is highly variable between species, in a global comparison of copepod data, it appears that species from higher latitudes may be more sensitive to copper. Environ Toxicol Chem 2016;35:2245-2251. © 2016 SETAC.