Microplastic-mediated delivery of di-butyl phthalate alters C. elegans lifespan and reproductive fidelity

TL;DR

Microplastics carrying di-butyl phthalate reduce the lifespan and fertility of C. elegans, highlighting potential health risks from environmental microplastics.

Contribution

This study reveals the combined toxic effects of microplastics and di-butyl phthalate on C. elegans reproduction and lifespan.

Findings

1 µm microplastics at 1 mg/L reduced brood size in C. elegans.

Microplastics with di-butyl phthalate increased embryonic lethality compared to microplastics alone.

Chronic microplastic exposure shortened C. elegans lifespan, worsened by di-butyl phthalate co-exposure.

Abstract

Microplastics harbor chemical additives and absorb pollutants from the environment. Microplastics pose a human health threat and have been found in nearly all human tissues. The toxicological pathways and physiological effects of microplastic-mediated chemical exposure following ingestion remain unknown. Here we use
C. elegans
to investigate the effects of di-butyl phthalate and polystyrene microplastic mixtures on fertility and lifespan. Our studies demonstrate that 1 µm microplastics at 1 mg/L exposure levels result in decreased brood size, whereas 1000 times fewer microplastics (1 µg/L) did not affect the number of eggs laid. While there was no change in brood size at 1 µg/L microplastic exposure levels, there was an increase in embryonic lethality. Microplastics-mediated delivery of di-butyl phthalate to
C. elegans
significantly reduced brood size and increased embryonic lethality compared to exposure to microplastics alone. This reproductive toxicity is potentially due to a stress response via DAF-16, as observed with microplastics and di-butyl phthalate co-exposure. Furthermore, chronic exposure to microplastics shortened the lifespan of
C. elegans
, which was further reduced with di-butyl phthalate co-exposure. The exacerbated defects observed with co-exposure to phthalate-containing microplastics underscore the risks associated with microplastics releasing the additives and/or chemicals that they have absorbed from the environment.