Ecotoxicological assessment of suspended solids: the importance of biofilm and particle aggregation
Motiei, Asa; Ogonowski, Martin; Reichelt, Sophia; Gorokhova, ElenaAbstract
Assessment of microplastic impacts in biota is challenging due to the complex behavior of the test particles and their interactions with other particulates, including microorganisms, in the environment. To disentangle responses to microplastic exposure from those to other suspended solids, both microplastic and natural particles must be present in the test system. We evaluated how microplastic, non-plastic particles, and biofilms interacted in their effects on survivorship using acute toxicity assay with Daphnia magna. The animals were exposed to microplastic and kaolin at different concentrations of suspended solids (SS; 10, 100, and 1000 mg/L) with a varying microplastic contribution (%MP; 0–80%) and biofilm (presence/absence) associated with the solids. Also, we examined how these exposure parameters (SS, %MP, and Biofilm) affected aggregate formation that was analyzed using particle size distribution data. Under the exposure conditions, Daphnia mortality was primarily driven by SS concentration but ameliorated by both microplastic and biofilm. The ameliorating effects were related to increased particle aggregation in the presence of biofilm and high %MP. In addition, a weak yet significant positive effect of the biofilm on the survivorship was observed, presumably, due to microbial food supply to the daphniids in the exposure system; the bacteria were utilized at the absence of other food. Therefore, the effects of both natural and anthropogenic particulates depend on the particle behavior and aggregation in the water governed by microbial communities and physicochemical properties of the particles, which must be taken into account in the hazard assessment of plastic litter.
Keywords
particle hazardous effects; biofilm; aggregation; microplastics; Daphnia magnaPublished in
Environmental Pollution2021, volume: 280, article number: 116888
Authors' information
Sustainable Development Goals
SDG6 Clean water and sanitation
UKÄ Subject classification
Environmental Sciences
Microbiology
Publication Identifiers
DOI: https://doi.org/10.1016/j.envpol.2021.116888
URI (permanent link to this page)
https://res.slu.se/id/publ/105165