Microplastic particles increase arsenic toxicity to rice seedlings

Area of Science:

• Environmental Science
• Plant Science
• Toxicology

Background:

• Microplastic pollution is a growing environmental concern.
• Arsenic contamination in agriculture poses risks to crop health and food safety.
• Understanding the combined effects of microplastics and arsenic on crops is crucial.

Purpose of the Study:

• To investigate the impact of polystyrene (PS) and polytetrafluoroethylene (PTFE) microplastics on rice seedlings exposed to arsenic (As).
• To assess the physiological and biochemical responses of rice to single and combined treatments of microplastics and As(III).
• To elucidate the mechanisms behind microplastic-arsenic interactions in rice plants.

Main Methods:

• Hydroponic experiments were conducted using rice seedlings.
• Rice was treated with varying concentrations of PS, PTFE, and As(III), individually and in combination.
• Biomass, root vigor, photosynthetic parameters, chlorophyll fluorescence, and oxidative stress indicators were measured.

Main Results:

• Rice biomass, root activity, and photosynthetic rates decreased with increasing concentrations of PS, PTFE, and As(III).
• Microplastics and As(III) induced oxidative stress, lipid peroxidation, and cell membrane damage in rice tissues.
• Lower concentrations of PS (0.04 g L⁻¹) and PTFE (0.1 g L⁻¹) mitigated some negative effects of As(III), while higher concentrations exacerbated them.
• PS and PTFE reduced As(III) uptake by rice, with decreased uptake observed at higher microplastic concentrations.

Conclusions:

• Both PS and PTFE microplastics, along with As(III), significantly inhibit rice growth and physiological functions.
• Microplastics can alter arsenic bioavailability and uptake in rice plants.
• The interaction between microplastics and arsenic is concentration-dependent, with potential for both mitigation and exacerbation of toxicity.