Abundance and distribution characteristics of microplastic in plateau cultivated land of Yunnan Province, China

Microplastic pollution in cultivated soil has received increasing attention recently. There may be more serious microplastic abundance but little research has been done in cultivated soil in plateau areas. To survey the pollution characteristics of microplastics in inland cultivated soil, 100 soil samples collected from 10 counties of Yunnan Province were investigated through density separation and microscopic examination. The research results showed that microplastic abundance was in the range of 0.9 x 10(3)to 40.8 x 10(3)particles (kg Ds)(-1)with average abundance of 9.8 x 10(3)particles (kg Ds)(-1). Moreover, compared with other studies on sediments, it was found that microplastic abundance in inland soil was one order of magnitude higher than that in offshore sediments. The use of plastic mulch and its long-term residue in cultivated soil was an important reason for microplastic pollution. In this survey, various morphologies of microplastics existed, including fragment (78.3%), transparent/translucency (49.7%), and micro-size microplastics (< 500 mu m) (89.3%). And the microplastic morphologies occurred in different degrees of aging phenomenon under the influence of the environment factors such as ultraviolet radiation. The findings provided the pollution status of microplastics in cultivated soil, and more attention should be paid to inland soil microplastic pollution.

Automated summary

This study investigated the pollution characteristics of microplastics in cultivated soil in Yunnan Province, revealing high levels of microplastic abundance mainly derived from plastic mulch. Various morphologies of microplastics were found in soil, and they exhibited different degrees of aging due to environmental factors. The findings emphasize the importance of paying more attention to microplastic pollution in inland soil.