Uptake and toxicity of Cd, Cu and Pb mixtures in the isopod Asellus aquaticus from waterborne exposure

Metal pollution is a serious threat to environmental health. While the aquatic isopod Asellus aquaticus L. (Isopoda) is an important decomposer of freshwater ecosystems, very little research has reported its long-term or incipient lethal concentrations for metals. Moreover, the lethal concentrations at a certain percentage (LCxs) that can be found in the literature are often based on unmeasured concentrations, which could lead to a severe underestimation of the actual toxicity. In the present exploratory study, the 1-, 4-, 7-, and 14-d LC10, LC20, and LC50 values of copper, cadmium, and lead for adult A. aquaticus were determined. The LCx values were calculated using the nominal concentrations, the effective concentrations, and the free ion activities. Incipient lethal values were determined as well. In general, surprisingly lower lethal concentrations were found than in other studies. Furthermore, the present study shows that lethal concentrations based on free ion activities were generally much lower than nominal and effective concentrations. Although almost all LC values were higher than the environmental quality standards (EQS), the Cu 14-d LC10 and several (incipient) Pb LC10 and LC20 values, all calculated with free ion activities, were lower than the EQS. We conclude that lethal or effective concentrations based on free ion activities provide a more realistic view, which is vital for environmental policy making. Environ Toxicol Chem 2017;36:2849-2854. © 2017 SETAC.

Section: Discussioncontrasting

confidence: 89%

Section: Discussionsupporting

confidence: 88%

Section: How Lcx Changes Over Timesupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

How lethal concentration changes over time: Toxicity of cadmium, copper, and lead to the freshwater isopod Asellus aquaticus

Ginneken

Blust

Bervoets

2017

“…Maund et al [56] also reported that copper reduced the population density of G. pulex between an NOEC and a lowest-observed-effective concentration (LOEC) of 11 and 14.6 mg L À1 in hard water laboratory waters. In contrast, A. aquaticus were able to survive and continue to grow in 10-d exposures of up to 1481 mg L À1 of copper [57]. These latter results cannot be explained by bioavailability differences, because while unreported, the reconstituted freshwater medium-hard water exposures would be expected to produce waters with pH values in a range of 7.6 to 8.0, and DOC < 1 mg L À1 [58].…”

Section: Effects Of Copper On Aquatic Invertebratesmentioning

confidence: 99%

A long‐term copper exposure in a freshwater ecosystem using lotic mesocosms: Invertebrate community responses

Joachim

Roussel

Bonzom

et al. 2017

A lotic mesocosm study was carried out in 20-m-long channels, under continuous, environmentally realistic concentrations of copper (Cu) in low, medium, and high exposures (nominally 0, 5, 25, and 75 μg L ; average effective concentrations <0.5, 4, 20, and 57 μg L respectively) for 18 mo. Total abundance, taxa richness, and community structure of zooplankton, macroinvertebrates, and emerging insects were severely affected at Cu treatment levels of 25 and 75 μg L . Some taxa were sensitive to Cu, including gastropods such as Lymnaea spp. and Physa sp., crustaceans such as Chydorus sphaericus, Gammarus pulex, and Asellus aquaticus, rotifers such as Mytilina sp. and Trichocerca sp., leeches such as Erpobdella sp., and the emergence of dipteran insects such as Chironomini. Other taxa appeared to be tolerant or favored by indirect effects, as in Chironimidae larvae, the emergence of Orthocladiinae, and the zooplankter Vorticella sp., which increased in the 25 and 75 μg L treatments. After approximately 8 mo of Cu exposure, the macroinvertebrate community in the high treatment was decimated to the point that few organisms could be detected, with moderate effects in the medium treatment, and very slight effects in the low-Cu treatment. Subsequently, most taxa in the high-Cu exposure began a gradual and partial recovery. By the end of the study at 18 mo, macroinvertebrate taxa richness was similar to control richness, although overall abundances remained lower than controls. After 18 mo of copper exposure, a no-observed-effect concentration at the community level for consumers was set at 5 μg L (4 μg L as average effective concentration), and a lowest-observed-effect concentration at 25 μg L (20 μg L as average effective concentration). Environ Toxicol Chem 2017;36:2698-2714. © 2017 SETAC.

A framework for ecological risk assessment of metal mixtures in aquatic systems

Nys

Regenmortel

Janssen

et al. 2018

Although metal mixture toxicity has been studied relatively intensely, there is no general consensus yet on how to incorporate metal mixture toxicity into aquatic risk assessment. We combined existing data on chronic metal mixture toxicity at the species level with species sensitivity distribution (SSD)-based in silico metal mixture risk predictions at the community level for mixtures of Ni, Zn, Cu, Cd, and Pb, to develop a tiered risk assessment scheme for metal mixtures in freshwater. Generally, independent action (IA) predicts chronic metal mixture toxicity at the species level most accurately, whereas concentration addition (CA) is the most conservative model. Mixture effects are noninteractive in 69% (IA) and 44% (CA) and antagonistic in 15% (IA) and 51% (CA) of the experiments, whereas synergisms are only observed in 15% (IA) and 5% (CA) of the experiments. At low effect sizes (∼ 10% mixture effect), CA overestimates metal mixture toxicity at the species level by 1.2-fold (i.e., the mixture interaction factor [MIF]; median). Species, metal presence, or number of metals does not significantly affect the MIF. To predict metal mixture risk at the community level, bioavailability-normalization procedures were combined with CA or IA using SSD techniques in 4 different methods, which were compared using environmental monitoring data of a European river basin (the Dommel, The Netherlands). We found that the simplest method, in which CA is directly applied to the SSD (CA ), is also the most conservative method. The CA has median margins of safety (MoS) of 1.1 and 1.2 respectively for binary mixtures compared with the theoretically more consistent methods of applying CA or IA to the dose-response curve of each species individually prior to estimating the fraction of affected species (CA or IA ). The MoS increases linearly with an increasing number of metals, up to 1.4 and 1.7 for quinary mixtures (median) compared with CA and IA , respectively. When our methods were applied to a geochemical baseline database (Forum of European Geological Surveys [FOREGS]), we found that CA yielded a considerable number of mixture risk predictions, even when metals were at background levels (8% of the water samples). In contrast, metal mixture risks predicted with the theoretically more consistent methods (e.g., IA ) were very limited under natural background metal concentrations (<1% of the water samples). Based on the combined evidence of chronic mixture toxicity predictions at the species level and evidence of in silico risk predictions at the community level, a tiered risk assessment scheme for evaluating metal mixture risks is presented, with CA functioning as a first, simple conservative tier. The more complex, but theoretically more consistent and most accurate method, IA , can be used in higher tier assessments. Alternatively, the conservatism of CA can be accounted for deterministically by incorporating the MoS and MIF in the scheme. Finally, specific guidance is also given related to specific issues, such as how to deal wit...