RESUMEN

Metal contaminants were found in a soil amended with a compost produced from household waste that included plastic debris. A strong correlation between the microplastics (MPs) distribution and the metal concentrations in the soil profile. Metals in the highest concentrations corresponded to the most significant plastic additives. As the total amount of plastic debris and the loss of metals and plastic particles were unknown, it was not possible to conclude that plastic debris is responsible for all of the metal contamination. Amount of calcium (Ca) in MPs (24.5 g kg-1 of MPs) are high in response to it use as filler in plastic formulation. As strontium (Sr) is an analogous of Ca, the potential of 87Sr/86Sr ratios to quantify MPs and nanoplastics (NPs) was tested. Elemental concentrations (Ca, Cd, Cr Pb, Ni and Sr) coupled with Sr isotopic ratios were compared in both amended soil and a reference soil without amendment. The 87Sr/86Sr ratios of the amended soil were less radiogenic than for the reference soil (0.724296 ± 0.000010 against 0.726610 ± 0.00009 for the 0-5 cm soil layer, respectively). The Sr isotopic ratio of MPs was also significantly less radiogenic (0.711527 ± 0.000010 for the 0-5 cm soil layer) than for soils. The MPs< 2 mm occurred in the ploughed soil depth with concentration varying from 1.19 to 0.09 mg kg-1. The NPs concentration stayed quite constant from 0 to 55 cm at around 0.25 µg kg-1. The presence of NPs until 55 cm soil depth was attested by the detection of polypropylene NPs by Py-GCMS in the soil solution < 0.8 µm. These results highlighted, for the first time, the NPs mobility throughout the soil depth and their ability to reach hydrosystems. It also demonstrated that Sr could be a potential tracer of the MPs< 2 mm and NPs amount occurring in soils.

RESUMEN

Soil is now becoming a reservoir of plastics in response to global production, use/disposal patterns and low recovery rates. Their degradation is caused by numerous processes, and this degradation leads to the formation and release of plastic nanoparticles, i.e., nanoplastics. The occurrence of nanoplastics in the soil is expected to both directly and indirectly impact its properties and functioning. Nanoplastics may directly impact the physiology and development of living organisms, especially plants, e.g., by modifying their production yield. Nanoplastics can also indirectly modify the physicochemical properties of the soil and, as a result, favour the release of related contaminants (organic or inorganic) and have an impact on soil biota, and therefore have a negative effect on the functioning of rhizospheres. However all these results have to be taken carefully since performed with polymer nano-bead not representative of the nanoplastics observed in the environment. This review highlight thus the current knowledge on the interactions between plants, rhizosphere and nanoplastics, their consequences on plant physiology and development in order to identify gaps and propose scientific recommendations.

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RESUMEN

Microplastics from the North Atlantic Gyre deposited on Guadeloupe beaches were sampled and characterized. A new method is developed to identify which elements were present as additives in these microplastics. The method used both acidic leaching and acidic digestion. Several elements (Al, Zn, Ba, Cu, Pb, Cd, Mn, Cr) were identified as pigments. Furthermore, some elements used as additives to plastics (especially the non-essential elements) seem to contribute to most of the acidic leaching, suggesting that these additives can leach and adsorb onto the surface microplastics, becoming bioavailable. Based on the acidic leaching element content, only Cd should represent a danger for fish when ingested. However, further studies are needed to determine the potential synergetic effect on health caused by the ingestion of several elements and microplastics.

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RESUMEN

While several studies have investigated the potential impact of nanoplastics, proof of their occurrence in our global environment has not yet been demonstrated. In the present work, by developing an innovative analytical strategy, the presence of nanoplastics in soil was identified for the first time. Our results demonstrate the presence of nanoplastics with a size ranging from 20 to 150 nm and covering three of the most common plastic families: polyethylene, polystyrene and polyvinyl chloride. Given the amount of organic matter in the soil matrix, the discrimination and identification of large nanoplastic aggregates are challenging. However, we provided an innovative methodology to circumvent the organic matter impact on nanoplastic detection by coupling size fractionation to molecular analysis of plastics. While photodegradation has been considered the principal formation pathway of nanoplastics in the environment, this study provides evidence, for the first time, that plastic degradation and nanoplastic production can, however, occur in the soil matrix. Moreover, by providing an innovative and simple extraction/analysis method, this study paves the way to further studies, notably regarding nanoplastic environmental fate and impacts.

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