Micro and nanoplastics are ubiquitous and can lead to adverse biological effects in exposed organisms. Organisms can also be co-exposed to plastics along with synthetic chemicals. In this work, using the NRC Zebrafish Embryo Toxicity test, we evaluated the potential toxicity of different sized plastic particles, along with the effects of combining them with the known toxicants, triphenyl phosphate, tetrabromobisphenol A and fluoxetine. Following chemical/plastic exposure, morphological abnormalities and behaviour were recorded, along with the chemical uptake of the toxicants by the larvae. The PS sphere particles used (0.42, 2.25 and 8.87 μm) exhibited no significant effects on larvae at the environmental concentrations tested (0.05–50 μg/mL) including no changes in larval behavioural activities. However, the presence of the micro/nanoplastic particles did increase the overt toxicity of the chemicals by changing their EC 50 . Additionally, for all three chemicals, some plastic sizes decreased larval behaviour during the baseline or first light-dark period. Plastic particles did not modify the chemical uptake by the larvae. This suggests that enhanced toxicity caused by the plastics is not linked to changes in chemical uptake, metabolism, or excretion as hypothesized. Additional studies are necessary to better understand the role of plastic particles in a multiple stressor environment. • Zebrafish exposed to micro/nanoplastic and anthropogenic chemicals. • Plastic particles altered chemical phenotypic toxicity. • Plastic particles modified zebrafish behaviour response to chemicals. • Micro/nanoplastics did not modify chemical uptake by larvae zebrafish.
Hermabessière et al. (2026) studied this question.