Interactive effects of flame retardant triphenyl phosphate and disposable face mask fibers in marine diatom Chaetoceros sp., and their effects on dietary exposure to marine crustacean Artemia salina

Plastic microfibers released from disposable face masks and triphenyl phosphate (ThP) are emerging contaminants of concern in the marine environment. However, there is a lack of scrutiny on their combined effect and dietary uptake in marine ecosystems. Therefore, the current study assessed the toxicity of ThP in the presence of MFs on the marine diatom Chaetoceros sp. and evaluated its effects on dietary exposure from Chaetoceros sp. to the crustacean Artemia salina . Liquid chromatography–mass spectrometry results revealed that the uptake of ThP was reduced in Chaetoceros sp. in the binary mixture due to the reduced bioavailability of ThP in the presence of MFs. However, the combination of MFs with ThP showed more reduction in cell viability of Chaetoceros sp. than ThP-single exposure. Abbott’s mathematical model revealed an additive mode of toxicity for the mixture group. X-ray photoelectron spectroscopy results revealed that the mixture of MFs with ThP exhibited the highest reduction in silica content in the diatom biosilica cell wall. The pollutant mixtures impaired the photosynthetic activity, triggered oxidative stress, and reduced the diatom cell viability. Notably, dietary exposure experiments revealed that ThP (0.5 and 1 mg/L) in the absence of MFs exhibited a significant uptake in Artemia salina. However, no significant uptake of ThP was observed in Artemia salina when fed with the binary mixture pre-treated diatoms. Consequently, only the diatoms pre-treated with ThP in the absence of MFs significantly affected the neurotransmitter activity in Artemia salina. This may subsequently have resulted in enhanced reactive oxygen species production, malondialdehyde levels, and mortality. Overall, this study highlights the propensity of MFs in modulating co-contaminant toxicity and dietary uptake in marine organisms.