Microplastics change soil properties, heavy metal availability and bacterial community in a Pb-Zn-contaminated soil

• Published in: Journal of hazardous materials 2022-02, Vol.424 (Pt A), p.127364-127364, Article 127364
• Main Authors: Feng, Xueying, Wang, Quanlong, Sun, Yuhuan, Zhang, Shuwu, Wang, Fayuan
• Format: Article
• Language: English
• Subjects: Dissolved Organic Matter; Heavy metal contamination; Metals, Heavy - toxicity; Microbial activity; Microbial community structure; Microbiota; Microplastics; Plastics; Soil; Soil ecosystem; Soil fertility; Soil Microbiology; Soil Pollutants - analysis; Zinc - toxicity
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.127364

Microplastics (MPs) co-occur widely with diverse contaminants in soils. However, few data are available on their impacts on soil chemical and microbial properties of heavy metal-contaminated soils. For the first time, we investigated the changes in chemical and microbial properties of a Pb-Zn-contaminated soil as induced by six different MPs, including polyethylene (PE), polystyrene (PS), polyamide (PA), polylactic acid (PLA), polybutylene succinate (PBS), and polyhydroxybutyrate (PHB), at two doses (0.2% and 2%, w/w). After 120 days of soil incubation, significant changes were observed in soil pH, dissolved organic carbon (DOC), NH4+-N, NO3−-N, available P, the availability of Zn and Pb, and the activities of soil enzymes. Overall, MPs especially at the dose of 2% decreased the richness and diversity of bacterial communities and altered microbial community composition, causing special enrichments of specific taxa. MPs increased predicted functional genes involved in xenobiotics biodegradation and metabolism. Generally, impacts were dependent on MPs’ type and dose. Changes in soil properties and heavy metal availability had significant correlations with bacterial community diversity and composition. Our findings imply that MPs co-occurring with heavy metals may change metal mobility, soil fertility, and microbial diversity and functions, thus causing a potential threat to soil ecosystem multifunctionality. [Display omitted] •MPs decreased bacterial richness and diversity of a Pb-Zn-polluted soil.•MPs changed soil properties and metal availability, and lowered soil fertility.•MPs altered microbial community composition, selectively enriching specific taxa.•Changes in Pb/Zn availability contributed to variations in microbial community.•Impacts of MPs varied dependent on their type and dose.