Uptake and Depuration Kinetics Influence Microplastic Bioaccumulation and Toxicity in Antarctic Krill (Euphausia superba)

Abstract

The discarding of plastic products has led to the ubiquitous occurrence of microplastic particles in the marine environment. The uptake and depuration kinetics of ingested microplastics for many marine species still remain unknown despite its importance for understanding bioaccumulation potential to higher trophic level consumers. In this study, Antarctic krill ( Euphausia superba) were exposed to polyethylene microplastics to quantify acute toxicity and ingestion kinetics, providing insight into the bioaccumulation potential of microplastics at the first-order consumer level. In the 10 day acute toxicity assay, no mortality or dose-dependent weight loss occurred in exposed krill, at any of the exposure concentrations (0, 10, 20, 40, or 80% plastic diet). Krill exposed to a 20% plastic diet for 24 h displayed fast uptake (22 ng mg h) and depuration (0.22 h) rates, but plastic uptake did not reach steady state. Efficient elimination also resulted in no bioaccumulation over an extended 25 day assay, with most individuals completely eliminating their microplastic burden in less than 5 days post exposure. Our results support recent findings of limited acute toxicity of ingested microplastics at this trophic level, and suggest sublethal chronic end points should be the focus of further ecotoxicological investigation.

Toward an Improved Understanding of the Ingestion and Trophic Transfer of Microplastic Particles: Critical Review and Implications for Future Research

“…This understanding is consistent with results reported in various laboratory‐based studies, which have often found efficient egestion of microplastic particles (Graham and Thompson 2009; Cole et al 2013; Ugolini et al 2013; Chua et al 2014; Kaposi et al 2014; Hu et al 2016; Ogonowski et al 2016; Grigorakis et al 2017; Dawson et al 2018; Ory et al 2018b; Woods et al 2018; Fernandez and Albentosa 2019; Song et al 2019). Efforts directed toward further characterization of gastrointestinal tract residence times would thus help to illuminate an important parameter in developing mass balance models aimed at assessing ingestion and trophic transfer and would further increase our understanding of the potential of the particles to bioaccumulate (Al‐Sid‐Cheikh et al 2018; Diepens and Koelmans 2018).…”

“…Concerns related to the potential for bioaccumulation are not necessarily limited to chemical contaminants but have recently been raised with respect to poorly soluble particulates such as engineered nanomaterials (ENMs; Hou et al 2013; Martirosyan and Schneider 2014; Lead et al 2018; Petersen et al 2019) and microplastic particles (Watts et al 2014; Van Cauwenberghe et al 2015; Karlsson et al 2017; Barboza et al 2018; Carbery et al 2018; Dawson et al 2018). A fundamental challenge in assessing the bioaccumulation of poorly soluble particulates is that the accumulation process is not driven by thermodynamic energy gradients, but by physical processes (Petersen et al 2019).…”

“…These studies have demonstrated that organisms at lower trophic levels, such as macrozooplankton, are capable of ingesting microplastic particles either indirectly or directly as a consequence of mistaking the particles for food, and are then themselves ingested by organisms at higher trophic levels, suggesting a potential mechanism that might support arguments for the bioaccumulation and biomagnification of microplastic particles. A common theme in these studies, however, is that the microplastic particles themselves have been observed throughout the gastrointestinal tract, with the particles subsequently egested following a depuration period (von Moos et al 2012; Au et al 2015; Grigorakis et al 2017; Santana et al 2017; Dawson et al 2018; Cong et al 2019; Fernandez and Albentosa 2019). In some studies the potential for translocation of the particles to internal tissues has been observed and reported (Hussain et al 2001; Browne et al 2008; von Moos et al 2012; Avio et al 2015; Abbasi et al 2018; Ding et al 2018).…”

Bioaccumulation and biomagnification of microplastics in marine organisms: A review and meta-analysis of current data

“…Bioaccumulation and biomagnification are two critical concepts used in ecological risk assessments to determine the extent of pollutant transport within food webs [ 19 ]. The classical concept of bioaccumulation and biomagnification usually refers to dissolved chemical contamination [ 20 ], although the terminology has been readily adopted by the MP literature [ 21 – 23 ]. In this study, bioaccumulation (or body burden) is defined as the net uptake of a contaminant (i.e.…”

in vitro Chemical and physical toxicity of polystyrene microplastics in human-derived cells

“…Furthermore, the adsorption of toxic reagents (persistent organic pollutants; POPs) or microorganisms from environments onto hydrophobic surface of microplastics increase their toxicity [17]. According to the previous reports on toxicity of microplastics, it has been mainly demonstrated the toxicity of plastic beads depending on their size or plastic types [18,19,20,21]. In secondary microplastics, however, over 50-65% in ocean environments are accounted by random shape of microfragments [22], hence the additional toxicity issue may be induced from shape differences.…”