As a class of emerging pollutants, microplastics have received great attentions in recent years owing to their persistence in the environment and potential toxic effects on organisms. They have been detected almost everywhere on the Earth, including the pedosphere, hydrosphere, atmosphere, biosphere, and even cryosphere. 

Microplastics can migrate between different media in the aqueous environment, which gives a high degree of similarity between microplastics and planktonic communities. The concept of “microplastic community” has been proposed to study the pollution characteristics and spatial variation of microplastics in the environment by applying the methods in community ecology. However, microplastic community is mostly applied at larger spatial scales such as basin-wide or even nationwide. There is a lack of comparison of the effectiveness of this concept at different spatial scales and geographical areas. 

In a study published in Science of The Total Environment, a research group led by Prof. WU Chenxi from the Institute of Hydrobiology (IHB) of the Chinese Academy of Sciences applied the methodology of the “microplastic community” to the medium spatial scale region (Hubei Province), and demonstrated the spatial pattern and influencing factors of microplastic pollution in this region. 

The researchers investigated microplastics in the surface water of 20 water bodies of 20 rivers and lakes in Hubei Province, and set up a total of 136 sampling sites. Microplastics were detected in all samples and the average abundance of microplastics in the water bodies was 1.74 items/L, which indicated that microplastic pollution is widespread in Hubei Province. Meanwhile, the negative correlation between the abundance of microplastics and the distance of sampling sites from residential areas indicated the influence of anthropogenic activity matters. 

To understand the influence of anthropogenic activity on microplastic pollution, the researchers extracted land use data as an indicator, and used microplastic community analysis to deal with multidimensional data.  

The researchers found that microplastic community composition did not differ significantly between water types, but significant differences emerged when the sample sites were divided by geographical region. Moreover, they identified several land use types significantly associated with microplastic community composition through db-RDA and correlation analysis. 

Several previous studies in large spatial scales have reported the similarity of microplastic communities decreases significantly with increasing distance between sample sites. However, in this study, the researchers only observed a very weak correlation.  

The researchers calculated "land use distance" with land use data, and found that it has a stronger correlation with the similarity of microplastic communities than geographical distance has. 

This study suggested that at moderate spatial scales, source differences due to different land use types may have a greater impact on microplastic pollution characteristics relative to spatial distance. The concept of “microplastic community” can be a helpful complementary tool for quantitatively assessing differences in the sources of microplastics in different regions.