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Through their accumulation in soils, microplastics have recently become a matter of concern. The aim of this review is to assemble and investigate the recent studies about microplastics in soil by focusing on their sources, occurrence, fate in soil, and analytical methods. The objective is also to clarify and elucidate their potential impacts on soil fauna, plants and microorganisms. In this paper, articles reporting the quantity of microplastics and their characteristics in soil at 62 sites situated across 17 countries were reviewed. The land type, microplastic abundances, types and sizes were compared. We summarized and discussed the sampling and analytical methods used and the variation of microplastic concentration according to their sources. The data showed that microplastic in soil from available global studies ranged from 0 to 3573×103 particles kg−1, with major dominance of polyethylene, polystyrene and polypropylene found in 50, 37 and 32 studies, respectively. The data analysis showed the high migration of small particles, spherical shape with high polymer density in the major studies. We also described the mechanisms controlling the vertical transport of microplastics: agricultural activity (plowing: at a depth between 10 cm (very shallow plowing) and 40 cm (deeper soil tillage)), bioturbation by soil organisms and plants, and leaching that can lead to the contamination of the groundwater.This review elucidated the behavior and fate of microplastics within the soil, serving as a reference for upcoming studies aimed at devising solutions to mitigate the toxicity associated with microplastics in soil.

Purpose: This study was carried out with the aim of improving the use of compost products as compost tea and humic substances fertilizers, to study the evolution and the degree of compost maturity, and to use the chlorophyll as an indicator of compost quality.Method: The compost tea and humic substances were prepared from different stages of a windrow compost (1/2 dewatered lagooning sludge + 1/2 green waste), the mineral content was investigated using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis. The growth test was carried out in a greenhouse for two months on two plants: Trigonella foenum-graecum (Fenugreek) and Lepidium sativum (Cress). Plant observations including stem elongation, biomass, stomatal conductance, chlorophyll fluorescence and total chlorophyll content in the leaf were investigated at the end of the experiment.Results: The findings revealed that compost tea and humic substances resulting from the initial stage and intermediate stage of composting present a lower stimulating effect on plants growth (biomass: 0.83-1.42 g/plant; total chlorophyll: 0.48-0.71 mg/plant). While those from the final stage showed significant effects on biometric and physiological properties (biomass: 1.399-2.396 g/plant; total chlorophyll: 0.74-0.83 mg/g). Furthermore, the chlorophyll performance, as a good indicator to determine plant stress and soil pollution, confirmed the maturity and the good quality of the final compost.Conclusion: Compost tea and humic substances treatments approved their bioactive properties and beneficial effects on plant growth and their physiological properties.