PET Peeves: investigating the combined effects of PET microplastic and copper on soybean growth

PET (polyethylene terephthalate) plastics naturally degrade in the environment forming microplastics which can make their way into soil, influencing physiochemical properties and altering plant growth . Microplastics in the environment have been shown to both increase or decrease the bioavailability of metals in soil depending on conditions like organic matter content, pH, and soil texture. Soybean were grown with and without microplastic (MP), in varying concentrations of copper. Bioavailable copper in the soil and copper concentration in the plant matter were measured. Organic matter percentage and pH of the soil will be measured before and after the experiment to monitor changes due to the addition of MPs. It was found that high copper levels with the addition of microplastics increased soil pH, which should influence copper bioavailability and plant biomass. The effect of increased pH in soil with combined 500 mg/kg copper and microplastics on the bioavailability and uptake of copper is awaiting sample analysis. Future studies should aim to lengthen plant growth time to potentially increase experimental effects and to increase number of replicates to decrease random error