This work shows that the plastic debris accumulated along with stranded Sargassum biomass in Guadeloupe’s beaches contains different forms of arsenic. Results from synchrotron nano X-ray Fluorescence (nanoXRF) and nano X-ray Absorption Near Edge Structure (nanoXANES) show that arsenate (As(V) in a tetrahedral coordination) present in seawater is complexed in the algae cell walls in an octahedral As(V) form, which is subsequently reduced to As(III) within the algae. Inorganic As(III) is either excreted or may undergo methylation and/or binding to glutathione, which is then stored in the algal cells or excreted. The areas where As is colocalized with a variety of metals (Si, K, Ca, Fe, Ni Cu and Zn) may correspond with areas in which algae tissues remain adhered to the surface of the plastics. On the opposite, the areas in which As is found together with Ti or Cl may correspond with areas in which the algae has been decomposed or in which As has been adsorbed after being secreted by the algae. Results from this study should be taken into account to assess the ecotoxicological impacts of Sargassum biomass accumulated on beaches, as well as for the planning of its valorization. Plastics within the Sargassum biomass can act as vectors for arsenic, facilitating its transfer to other environmental compartments where the biomass is used or when it is ingested by various organisms. In a context of a growing problem of plastic pollution and a more and more frequent algae blooms, these results are particularly relevant.

中文翻译：

---

堆积在马尾藻搁浅生物质上的塑料碎片是不同 As（V） 和 As（III） 形式的载体


这项工作表明，瓜德罗普海滩与搁浅的马尾藻生物质一起积累的塑料碎片含有不同形式的砷。同步加速器纳米 X 射线荧光 （nanoXRF） 和纳米 X 射线吸收近边缘结构 （nanoXANES） 的结果表明，海水中存在的砷酸盐（四面体配位中的 As（V））在藻类细胞壁中以八面体 As（V） 形式复合，随后在藻类中还原为 As（III）。无机 As（III） 要么被排泄，要么可能发生甲基化和/或与谷胱甘肽结合，然后储存在藻类细胞中或排泄。As 与各种金属（Si、K、Ca、Fe、Ni Cu 和 Zn）共定位的区域可能与藻类组织保持粘附在塑料表面的区域相对应。相反，与 Ti 或 Cl 一起发现 As 的区域可能与藻类分解的区域或 As 被藻类分泌后被吸附的区域相对应。在评估海滩上积累的马尾藻生物量的生态毒理学影响以及规划其价值时，应考虑这项研究的结果。马尾藻生物质中的塑料可以作为砷的载体，促进其转移到使用生物质或被各种生物体摄入的其他环境区间。在塑料污染问题日益严重和藻类大量繁殖越来越频繁的背景下，这些结果尤为相关。