Microplastics Increase Soil pH and Decrease Microbial Activities as a Function of Microplastic Shape, Polymer Type, and Exposure Time

Microplastic pollution is a topic of increasing concern, especially since this issue was first addressed in soils. Results have so far been variable terms effects, suggesting that there substantial context-dependency microplastic effects soil. To better define conditions may affect microplastic-related impacts, we here examined as function shape and polymer type, tested if on soil properties microbial activities change with incubation time. In our laboratory study, evaluated twelve different secondary microplastics representing four shapes: fibers, films, foams fragments; eight types: polyamide (PA), polycarbonate (PC), polyethylene (PE), polyester (PES), terephthalate (PET), polypropylene (PP), polystyrene (PS), polyurethane (PU). We mixed the sandy (0.4% w/w) incubated at 25°C for 31 days. Then, collected samples 3rd, 11th, 31st day, measured pH, respiration enzyme (soil enzymatic activities). Our results showed could depending were altered Soil pH increased fragments overall decreased days then increased. PE affected by time, declining over Overall, acid phosphatase activity not or type. ?-D-glucosidase foams, cellobiosidase films while N-acetyl-?-glucosaminidase fibers fragments. Enzymatic fluctuated during except N-acetyl-?-glucosaminidase, which trend negatively correlated relationship less strong when added to study adds evidence research should embrace complexity diversity microplastics, highlighting role type influencing effects; additionally, show time also parameter consider, are dynamic even short term.