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Plastic debris is a complex and persistent environmental contaminant that has received a high amount of attention in the last few years. Understanding the sources, transport, fate, occurrence, and health risks of microplastics (MPs) in the environment is essential as millions of tons of plastic are manufactured and released into the environment. There is a high possibility that MPs will accumulate and retain within continental environments and have effects on the environment and human health. This review elucidates the outcomes of studies related to the prevalence, transport, fate, and health risks of MPs in soil and freshwater environments. The review shows that the sources of MPs are diverse and extensive and their occurrence, transport, fate, and health risks in the environment are affected by their physico-chemical characteristics and by natural factors. Implemented legislation or regulatory plans to reduce MPs contamination of the environment have been reviewed in this study. Moreover, management options are presented.

Efforts to reduce the toxic effects of microplastics (MPs) on the environment have increased globally in recent years. However, the existing models used for the simulation of contaminant transport in groundwater are meant for dissolved substances, which is not suitable for studying MPs. Therefore, in this study, the transport of MPs in a saturated porous medium was modeled by establishing governing equations. Simulations were performed using the finite element method to examine the effects of the parameters of the governing equations on the transport of MPs. The results suggest that it is necessary to reduce the diffusivity of MPs and increase the water flow velocity, porosity, and first-order attachment coefficient to effectively contain this environmental hazard. From the simulation results, it can be derived that a combination of low diffusivity, fast water flow velocity, and high soil porosity may reduce the amount of MPs that are leaked into groundwater environments. The modeling and simulations performed in this study provide a clear understanding of the transport phenomena of MPs with applications in combating water pollution. [ABSTRACT FROM AUTHOR]

There are some weaknesses in the methodology of original paper "Informal landfill contributes to the pollution of microplastic in the surrounding environment" published in Environmental Pollution. We commented on the groundwater sampling procedure that affect the calculated concentrations of microplastics in groundwater. Important information related to the description of sampling wells, informal landfill, and the exact description of sample collection method are missing. In addition, significant data related to the groundwater like water level, flow direction, and velocity have been skipped, which are fundamental in groundwater related studies. There should be a clear diagram of landfill location and sampling wells in the landfill, for appropriate understanding of microplastics (MPs) pollution in surrounding environment of a landfill. [ABSTRACT FROM AUTHOR]

Researchers interested in a paper's statement or aiming to acquire useful information from scientific papers rely heavily on references. Additionally, calculation accuracy is important for ensuring the technical soundness of scientific papers. However, inaccurate citations and calculations are common in scientific literature. A recently published paper in the Journal of Hazardous Materials reported a study on microplastics in groundwater and surface water from coastal south India (Tamil Nadu state) and the heavy metal adsorption capacities of different polymers. In this study, we identified critical calculation errors and incorrect reference citations. [ABSTRACT FROM AUTHOR]

This paper discusses some critical weak points and mistakes identified in the original paper. The authors disregarded the importance of field blanks, sampling equipment, and well specifications for proper quality assurance and control. Beneficial field practices guarantee highly reliable results of laboratory analysis for microplastics. In addition, polymer type (chemical composition) and shape (form) are different classification criteria, but the authors mixed these in their description. The distribution and transport of microplastics should be properly understood, along with a knowledge of groundwater flow conditions, such as flow direction and velocity, in the study area. [ABSTRACT FROM AUTHOR]

Microplastic (MPs) contamination in groundwater has received massive attention since plastic waste has been released directly into the environment. This study investigates MPs contamination in groundwater on the Jeju volcanic Island, Korea. To the best of our knowledge, this is the first study to identify MPs in groundwater from volcanic islands. A total of 21 sites were sampled for groundwater wells and springs in July and September (2021). Sampling was performed without cross-contamination through quality assurance and quality control. The results showed that MPs abundance ranged from 0.006 to 0.192 particles/L in groundwater samples. Additionally, MPs were detected in deep groundwater wells where the groundwater level was 143 m below ground surface. Eight MPs polymer types, including polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, polyamide, acrylonitrile butadiene styrene, and polyurethane, were detected using Micro-Fourier Transform Infrared Spectroscopy (μ-FT-IR). Most of the detected MPs size ranged from 20 to 100 μm, accounting for 95% of the total. Fragments and fiber shaped MPs were detected, with the majority of them being fragmented in groundwater samples. The concentrations of MPs and major ions in groundwater showed a positive correlation. A negative correlation was observed between MPs concentration and topographic elevation (r = −0.59, p = 0.01). The source of MPs contamination is most likely attributed to agricultural activities, such as plastic mulching and greenhouses, which account for most of the land use in the study area. In this study, MPs entered the aquifer through the soil at the surface and seeped through cracks in fractured rock on basalt with sealed groundwater wells. This study takes 500 L of samples to prevent sample bias, reveal plastic contamination in groundwater, and indicating the characteristics and sources of contaminated plastics. [Display omitted] • Most MPs detected in groundwater were smaller than 50 μm. • Eight polymers were identified, with PP and PE being dominant types in groundwater. • Predominant shapes of MPs in groundwater were fragments. • MPs abundance and groundwater levels have a negative correlation. [ABSTRACT FROM AUTHOR]