Research Progress on Pollution Characteristics and Ecological Effects of Micro/Nano Plastics in Soil under the Action of Climatic Factors

Large amounts of plastic wastes have accumulated in terrestrial ecosystem due to the abuse of plastic products. Soil ecosystem is facing great stresses by the micro/nano plastics, the fractions that fragmented from the weathered plastic wastes, and by extreme weather events such as high temperature, drought, and heavy rainfall caused by the global climate change. The climatic environmental factors such as temperature and precipitation affect the occurrence, transportation, conversion, and toxicity of micro/nano plastics in soil. The effects of different climatic factors on pollution characteristics and migration of micro/nano plastics in soil were reviewed. The combined effects of different climatic factors and micro/nano plastics on the soil ecology were also discussed. It was found that warming, drought, freeze-thaw, and flood could increase the abundance of micro/nano plastics in soil and accelerate the aging of micro/nano plastics. The soil properties, nutrient cycling, and plant growth could be influenced by the combination of climatic factors and micro/nano plastics. The soil carbon and nitrogen cycling were significantly affected by warming or drought accompany with existences of micro/nano plastics. Future research should focus on the effects of typical climatic factors on the aging characteristics and environmental behavior of micro/nano plastics and their joint effects on key biogeochemical cycling processes in soil.