The combined toxic effects of polystyrene microplastics and different forms of arsenic on the zebrafish embryos (Danio rerio)

Microplastics have been widely studied for their ability to adsorb heavy metals. In the natural environment, arsenic exists in different forms and its toxicity depends mainly on its form and concentration. However, different forms of ar-senic combined with microplastics have yet to be explored for their biological hazards. This study was conducted to reveal the adsorption mechanism of different forms of arsenic onto PSMP and to study the effects of PSMP on the tissue accumulation and developmental toxicity of different forms of arsenic in zebrafish larvae. As a result, the absorbing ability of PSMP for As(III) was 35 times higher than that of DMAs, in which hydrogen bonding plays an important role in the adsorption process. In addition, the adsorption kinetics of As(III) and DMAs on PSMP were in good agree-ment with the pseudo-second-order kinetic model. Furthermore, PSMP reduced the accumulation of As(III) early in zebrafish larvae development, thereby increasing hatching rates compared with the As(III)-treated group, whereas PSMP had no significant effect on DMAs accumulation in zebrafish larvae, but decreased hatching rates compared with the DMAs-treated group. In addition, except for the microplastic exposure group, the other treatment groups could lead to a decrease in the heart rate of zebrafish larvae. Both PSMP+As(III) and PSMP+DMAs exhibited aggra-vated oxidative stress compared with PSMP-treated group, but PSMP+As(III) caused more severe oxidative stress at later stages of zebrafish larvae development. Moreover, specific metabolic differences (e.g., AMP, IMP, and guanosine) were produced in the PSMP+As(III) exposure group, which would mainly affect purine metabolism and promoted

Automated summary

This study aimed to reveal the adsorption mechanism of different forms of arsenic onto PSMP and investigate the effects of PSMP on tissue accumulation and developmental toxicity in zebrafish larvae. The results showed that PSMP had a higher adsorption ability for As(III) than DMAs, with hydrogen bonding playing an important role in the process. PSMP reduced the accumulation of As(III) and increased hatching rates in zebrafish larvae, but had no significant effect on DMAs accumulation. PSMP+As(III) exhibited more severe oxidative stress at later stages of zebrafish larvae development.