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As an emerging environmental pollutant, microplastics (MPs) have received widespread attention. Recently, studies examining microplastic pollution in plateau lakes have been increasing, but few have examined the distributions, sources, and fates of MPs in different plateau areas. In this work, the abundances and characteristics of MPs in surface waters and sediments in lakes of the Qinghai-Tibet Plateau (QTP) and Yunnan-Guizhou Plateau (YGP) were systematically investigated. The abundances of MPs in the lakes of the QTP ranges within 0.05-1.8 n/L in surface waters and 10-2643.7 n/kg in sediments. In the lakes of the YGP, the abundances of MPs ranged within 1.3-10.1 n/L in surface waters and 171.7-4260 n/kg in sediments. The dominant shape, color, and size class of MPs were fiber, transparent, and 0-0.5 mm in plateau lakes, respectively. MPs were mainly composed of polypropylene, polyethylene, and polyethylene terephthalate polymers. The different sources of MPs in the QTP and YGP lakes were mainly due to differences in human activities. The primary sources of microplastic pollution in the lakes of the QTP were tourism and atmospheric transport, while sewage discharge, agriculture, and fishing activities were the main sources of MPs in urban lakes of the YGP. Although the level of microplastic pollution in plateau lakes was relatively low, the sources should be identified and monitored so that the effects and extent of microplastic pollution in these fragile environments can be fully understood. This study provides a valuable dataset and theoretical basis for subsequent research on microplastic pollution in plateau lakes., Competing Interests: Declaration of competing interest The authors declare that they have no know competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Microplastics (MPs) in soils have attracted attention worldwide. However, there are few studies on the abundance and morphological characteristics of MPs under different land use patterns in karst areas. In this work, the distribution characteristics of MPs in soils from five different land use patterns, including industrial mining warehouse (IW), cropland (CL), forest land (FL), grassland (GL), and garden land (GP) in karst mountainous areas of southwest China were investigated. The results suggested that soils in Karst Plateau of Guizhou province under different land use patterns have all been polluted by MPs. The average microplastic abundances of IW, CL, FL, GL, and GP were 3114, 2948, 2770, 2718, and 4200 item kg -1 . In the GP and GL soils, foam was the dominant form of MPs (47.53 % and 45.92 %), with pellet MPs accounting for the smallest proportion, while in IW, CL, and FL soils showed the opposite result. The MPs in all soil samples were dominated by small particles (0-0.5 mm), and the main components were PE, PP, PVC, and PET. Meanwhile, the characteristics of MPs in CL soils varied depending on the planted crops. The average abundances of soil microplastics in farmlands planted with corn, pepper, cabbage, watermelon, and other crops were 2504, 2792, 2987, 2370, and 3655 item kg -1 . We suggested that land use pattern and crop type may influence karst soil microplastic contamination. The results of this study provide a scientific basis for understanding and controlling the distribution, degradation, and migration of MP pollution in karst regions., Competing Interests: Declaration of competing interest The authors declare that they have no know competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Soil microplastics (MPs) pollution is a global concern, but the distribution of MPs and the factors affecting the distribution of MPs in different ecologically fragile karst areas remain poorly understood. Here, we investigated the spatial distribution, characteristics, and composition of MPs in different ecologically fragile karst areas of Guizhou Province and explored the relationship between ecosystem fragility and MPs. Structural equation models combined with robust random forest (RF) models were used to clarify the effects of karst soil properties on MPs and quantify their relative contributions. The abundance of soil MPs in ecologically fragile karst areas was 2949 item kg -1 , and the risk of MPs contamination was highest in medium-fragile areas. The robust RF models precisely predicted the abundance of soil MPs in different fragile areas, and the mean root mean square error and R 2 were 0.21 and 0.93, respectively. The contribution of karst soil properties to the abundance of MPs was estimated. Some soil chemical properties had a significant effect (p < 0.05) on MPs pollution in ecologically fragile karst areas. The results of our study suggest that the fragile ecological environment may exacerbate MPs pollution. Our study also contributes to establish a scientific theoretical foundation for the utilization of plastics and the prevention and control of microplastics pollution in karst ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

An increasing number of researchers have focused on microplastics (MPs) pollution in inland freshwater lakes due to its ecotoxicity, while little is known about the effects of hydrological periods on MPs distribution. Therefore, this study aims to investigate MPs distribution, morphological characteristics and physicochemical indices in various environments in dry and wet periods in Caohai Lake. The results exhibited that cultivated soil, water, and sediment in Caohai Lake have been polluted by MPs in dry and wet periods. There were pellets, fragments, film, and fibers of MPs in both dry and wet periods, and MP foam was additionally found in the wet period. MPs with 0 to 0.5 mm possessed the largest proportion in the five environments in dry and wet periods, followed by MPs with 0.5 to 1 mm and 1 to 5 mm. In Caohai Lake, the black, white, green, red, and transparent MPs in dry period, and black, colourful, grey, red and transparent MPs in wet period were found. The developed structural equation model confirmed that MPs in sediment were probably mainly from soil. There are negative effects of the relative abundance of MPs from cultivated soil to lake water in the dry period, whereas the opposite is true in the wet period. Interestingly, the complex and fast water velocity in the estuary in the wet period led to a lower relative abundance of MPs in its sediment in comparison with the dry period. The distribution model of MPs in estuary and lake water in dry and wet periods is not inconsistent. Our results suggest that the related government department should take measures to reduce the MPs pollution in Caohai Lake, especially from the source., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Microplastics (<5 mm) (MPs) are widely distributed throughout the world, and their accumulation and migration in the environment have caused health and safety concerns. Currently, most of the reviewed literatures mainly focus on the distribution in various environmental media, adsorption mechanisms with different pollutants, and characterization of MPs. Therefore, the present review mainly highlights the characterization techniques of MPs and the underlying mechanisms of their combination with conventional coexisting substances (heavy metals, organic pollutants, and nutrients). We observed that massive MP pollution has been found in many areas, especially in Africa, Asia, India, South Africa, North America and Europe. The separation methods of MPs in different environmental media are basically similar, including sampling, pre-treatment, flotation, filtration and digestion. The combination of multiple characterization technologies can more precisely identify the shape, abundance, colour, and particle size of MPs. Notably, although recent reports have confirmed that MPs can act as carriers of heavy metals and carry them into organisms to cause harm, MPs have different adsorption and desorption characteristics for various heavy metals. The adsorption capacity of organic pollutants onto MPs is closely related to their hydrophobicity, specific surface area and functional group characteristics. The relative abundance of MPs in sediments and lakes had a significantly positive correlation with the mass concentration of total nitrogen in lake water, but this finding still needs to be further verified. Based on current research, we suggest that future MP research should focus on characterization technology, environmental migration, ecological effects, health risks and degradation methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The Wanshan mercury (Hg) mine in Guizhou Province is one of the main Hg-producing mines in China, resulting in serious Hg pollution in soil and wastewater. Therefore, the present study is mainly aimed to investigate the current degree of heavy metal pollution and compared the microbial diversity in the Wanshan Hg mine and its surrounding environment. The results showed the distribution of the pollution load index values was low in the west and high in the east. The northwestern (Aozhai River), northern (Meizi Stream), and southwestern parts of the study area and the area surrounding Erkeng did not reach moderate pollution. Mercury accounted for the majority of the potential ecological risk index values, reaching 67.62%, while the proportions of Cd and As were 15.75% and 10.75%, respectively. Mercury was found mainly in a residual state, which had an average proportion of 71.09%. In the three regions, Proteobacteria and Actinobacteria had the highest relative abundances. According to linear discriminant analysis effect size, the indicator species in the Hg mining area, woodland and cultivated land was f&#95;&#95;67-14 (belonging to a family of Solirubrobacterales), Reyranellales and Reyranellaceae, Intrasporangiaceae, respectively. In summary, this study for the very first time estimated that the higher Hg, Cd and As pollution existed in Wanshan Hg mine since their concentration in the all soil samples totally exceeded the standard value (GB15618-2018), while Cd and As pollution in soil was commonly ignored by the previous study. The cultivated land had higher community richness than the mercury mining district and woodland. Our results suggested that the relevant local departments need to take more active measures to solve the problem of high levels of Hg, Cd, and As in the local soil, and prevent their adverse effects on humans., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

The speciation and activity of heavy metals in farmland were changed with the different soil properties and flooded environment, especially in the complex and rainy environment in soil of Guizhou Province. The objective of this study was to explore the concentrations of a variety of heavy metal activity and the speciation of those heavy metals in rhizosphere soil at different growth stages of Brassica campestris L. in a Karst mountainous area. Tessier's five-stage sequential extraction procedure, the potential ecological risk index, a Bayesian network, accumulation factors, translocation factors and a laboratory simulation experiment were applied in this study. The results showed that (1) no heavy metal concentrations (except the Cd concentration) exceeded the limits of the soil environmental quality risk control standards for soil contamination of agricultural land in China (GB15618-2018). (2) The orders of the accumulation factor and translocation factor values were Zn > Cd > Cu > Pb > Cr and Cd > Cu > Zn > Pb > Cr, respectively. The order of the heavy metal contents of different tissues during the whole growth period was roots > leaves > stems. (3) The indoor simulation test exhibited that the dry-wet alternation and flooding can reduce Cd activity in soil. (4) Redox potential (Eh), rather than pH or organic matter, was the main factor impacting the total content and chemical speciation of heavy metals in the soil, based on a dynamic Bayesian network. Based on the results, we suggest that the activity of heavy metals should be improved by using dry-wet alternation, whereas the proportions of ion-exchangeable forms of heavy metals are relatively low in the study area (except for Cd). Several measures may be taken to enhance soil acidity and reduce the Cd activity during Brassica campestris L. cultivation., (Copyright © 2020 Elsevier Inc. All rights reserved.)