Ingestion and contact with polyethylene microplastics does not cause acute toxicity on marine zooplankton

Abstract

Toxicity of polyethylene microplastics (PE-MP) of size ranges similar to their natural food to zooplanktonic organisms representative of the main taxa present in marine plankton, including rotifers, copepods, bivalves, echinoderms and fish, was evaluated. Early life stages (ELS) were prioritized as testing models in order to maximize sensitivity. Treatments included particles spiked with benzophenone-3 (BP-3), a hydrophobic organic chemical used in cosmetics with direct input in coastal areas. Despite documented ingestion of both virgin and BP-3 spiked microplastics no acute toxicity was found at loads orders of magnitude above environmentally relevant concentrations on any of the invertebrate models. In fish tests some effects, including premature or reduced hatching, were observed after 12 d exposure at 10 mg L of BP-3 spiked PE-MP. The results obtained do not support environmentally relevant risk of microplastics on marine zooplankton. Similar approaches testing more hydrophobic chemicals with higher acute toxicity are needed before these conclusions could be extended to other organic pollutants common in marine ecosystems. Therefore, the replacement of these polymers in consumer products must be carefully considered.

Multi-Laboratory Hazard Assessment of Contaminated Microplastic Particles by Means of Enhanced Fish Embryo Test With the Zebrafish (Danio rerio)

“…Likewise, PE particles up to 100 mg/L (with a diameter between 11 and 13 µm) without pollutants did not show any embryotoxic or teratogenic effects after 96 h of exposure. Similar results were found after exposure of marine medaka (Oryzias melastigma) using 10 mg/L of 11-13 µm PE particles (Beiras et al, 2018). Lithner et al (2011) ranked polymers based on monomer hazard classification, and PE was classified as one of the less hazardous polymers for humans and the environment.…”

“…Regarding MPs spiked with pollutants, in the only comparable experiment so far, embryonic stages of marine medaka were exposed to 10 mg/L PE spiked with BP3 at the same concentration as in present study. Exposure to MP + BP3 induced premature hatching and a significant decrease in hatching rate (Beiras et al, 2018). The same authors also demonstrated a direct contact of MPs to villi at the surface of the marine medaka chorion, which may facilitate the uptake of toxicants.…”

“…For Japanese medaka, the embryonic stage lasts until days 10-11 dpf (Padilla et al, 2009), whereas this period is restricted to 48-72 hpf in zebrafish, depending on temperature (Kimmel et al, 1995). Similarly to Japanese medaka, mean hatching time for marine medaka is 11 dpf (Beiras et al, 2018). Therefore, future investigations on MPs effects in zebrafish might consider prolonged or even chronic exposure; however, this would be an animal experiment clearly requiring authorization under Directive 2010/63/EU.…”

A 2‐Tier standard method to test the toxicity of microplastics in marine water using Paracentrotus lividus and Acartia clausi larvae

“…The evaluations employ Paracentrotus lividus and Acartia clausi planktonic larvae because they are common biological models in marine research, and standard methods for toxicity testing are available (International Organisation for Standardisation ; Beiras et al ). These biological models have been previously used to assess the toxicity of plastic additives (Tato et al ) and microplastics (Beiras et al ), and showed similar sensitivity to both types of pollutants.…”

Editorial: Impacts of Marine Litter

“…Conventional plastics are non-biodegradable and they may persist in the environment for hundreds of years but also because of hydrodynamics and exposure to light, they may fragment into small particles readily taken up by marine organisms. Microplastics and nanoplastics are of particular concern: ingested by even the smallest zooplankton species they can transfer hydrophobic pollutants (and plastic additives) into the trophic webs, although thermodynamic models and experimental data provide conflicting results and more research is needed in this field (Beiras et al, 2018;Burns and Boxall, 2018;Ogonowski et al, 2018). Finally, plastic at sea may transport alien species over long distances or act as substratum for vagile and epistratum benthos, providing a support to colonization (Casabianca et al, 2019).…”