TY - JOUR

T1 - Bioplastic (PHBV) addition to soil alters microbial community structure and negatively affects plant-microbial metabolic functioning in maize

AU - Brown, Robert W.

AU - Chadwick, David R.

AU - Zang, Huadong

AU - Graf, Martine

AU - Liu, Xuejun

AU - Wang, Kai

AU - Greenfield, Lucy M.

AU - Jones, Davey L.

PY - 2023/1/5

Y1 - 2023/1/5

N2 - Microplastic contamination poses a significant threat to agroecosystem functioning, provoking a move away from the use of conventional oil-based plastics in agriculture, to biodegradable alternatives that may be degraded over a shorter timescale. The impact of these bioplastics on plant and soil health, however, has received relatively little attention. Here, we investigated the effect of soil loading (0.01%, 0.1%, 1% and 10%) of biobased microplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) on soil and plant (Zea mays L.) health and function. We showed that PHBV caused a dose-dependent reduction in plant growth and foliar nitrogen (N) content while untargeted metabolite analysis revealed significant shifts in foliar metabolic function. These results were also reflected in soil, where PHBV led to reduced plant availability of both ammonium and nitrate. Soil 14C-isotope tracing and 16S metabarcoding revealed that PHBV suppressed microbial activity, reduced bacterial diversity and shifted microbial community structure, inducing a major shift in soil metabolic pathways, and thus functioning. Overall, our data suggests that the bioplastic PHBV is not environmentally benign and that contamination levels as low as 0.01% (0.01 mg kg-1) can induce significant short-term changes in both plant and soil microbial functioning, with potential implications for long term agroecosystem health.

AB - Microplastic contamination poses a significant threat to agroecosystem functioning, provoking a move away from the use of conventional oil-based plastics in agriculture, to biodegradable alternatives that may be degraded over a shorter timescale. The impact of these bioplastics on plant and soil health, however, has received relatively little attention. Here, we investigated the effect of soil loading (0.01%, 0.1%, 1% and 10%) of biobased microplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) on soil and plant (Zea mays L.) health and function. We showed that PHBV caused a dose-dependent reduction in plant growth and foliar nitrogen (N) content while untargeted metabolite analysis revealed significant shifts in foliar metabolic function. These results were also reflected in soil, where PHBV led to reduced plant availability of both ammonium and nitrate. Soil 14C-isotope tracing and 16S metabarcoding revealed that PHBV suppressed microbial activity, reduced bacterial diversity and shifted microbial community structure, inducing a major shift in soil metabolic pathways, and thus functioning. Overall, our data suggests that the bioplastic PHBV is not environmentally benign and that contamination levels as low as 0.01% (0.01 mg kg-1) can induce significant short-term changes in both plant and soil microbial functioning, with potential implications for long term agroecosystem health.

KW - Biodegradable microplastic

KW - Crop growth

KW - Ecotoxicological assessment

KW - Metabolomics

KW - Microplastic pollution

U2 - 10.1016/j.jhazmat.2022.129959

DO - 10.1016/j.jhazmat.2022.129959

M3 - Article

VL - 441

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

SN - 0304-3894

M1 - 129959

ER -