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Tire wear particles (TWP) are a major source of microplastics in the environment. Despite their prevalence, the effects of tire particle leachates on marine microplankton communities remains poorly understood. In this study, we assessed the acute impacts of tire particle leachates on the structure of coastal microplankton assemblages from the Canary Islands. Five laboratory experiments were conducted, exposing microplankton to a range of leachate dilutions over 72 h, with TWP leachates prepared from an initial concentration of 1 g L⁻¹ .Our results revealed that the abundances of diatoms, most dinoflagellates, and ciliates were significantly reduced following exposure to leachates, with median effective concentrations (EC 50 ) ranging from 30 to 660 mg L -1 depending on the plankton community. Interestingly, Ostreopsis cf. ovata, a harmful algal bloom (HAB)-forming species, exhibited relatively high tolerance to tire particle leachates compared to other microplankton. Compared to other marine biota, ciliates appear to be most vulnerable plankton group to tire particle leachates (EC 50 = 30 and 146 mg L -1 ). The higher tolerance of O. cf. ovata to pollution compared to other phytoplankton species (resource competitors), in combination with other factors, may contribute to the rise of HABs in polluted coastal areas. Although field data on TWP are limited, the observed negative effects on microplankton occurred at environmentally relevant concentrations. Our results indicate that TWP pollution can significantly impact marine planktonic communities, highlighting the urgent need to reduce TWP emissions and develop less toxic tire rubber additives., 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 © 2025. Published by Elsevier Inc.)

The precipitation of sparingly soluble calcium phosphate in calcareous soils decreases the bioavailability of macronutrients, which makes their addition by way of fertilisers necessary. Sludge resulting from treating urban wastewater does not only provide significant amounts of phosphorus, but also helps lower the pH, thus increasing its bioavailability. The loss of part of soil nutrients due to irrigation or rain can contaminate groundwater. In order to assess the movement of phosphorus, a experiment was conducted on percolation columns, to which different doses of wastes were applied. The pH decreased by as much as 0.89 units, as well as the assimilable and soluble P, in intervals of 20 cm of depth, obtaining maximum values of 254 mg P kg−1 and 1455 μg P kg−1 respectively, and the P present in the leached water collected, which did not surpass 95 μg PL−1. The intent was to learn which was the majoritarian inorganic formed crystalline phase that immobilised the movement of phosphorus through the percolation column. The results obtained by the diffraction of X-rays are not conclusive, although they point to the formation of octacalcium phosphate. The diffractograms of the studied samples have similar diffraction lines to those of apatites. [ABSTRACT FROM AUTHOR]

Asturias has numerous derelict Hg mine sites as a legacy of a past intensive mining activity, and the most important of these are located in the Caudal River catchment. These mines have been abandoned without remediation, and the legacy of these mine works remains currently in the form of mine wastes stocked in piles on the surface. In the exploited ore deposits, As is quite abundant in the form of sulphides (As-rich pyrite), sulpho-arsenides (arsenopyrite, realgar and orpiment), and supergenic minerals (scorodite). Significant quantities of mine and metallurgical wastes stocked at surface in spoil heaps of different age and size, and old galleries and transversals acting as pseudokarstic aquifers, are potential pollution pathways for the spreading of As to the environment. As a consequence of the weathering of As-rich minerals, As contents are high in mine effluents and spoil heap leachates. In the spoil heaps, waste materials are subjected to the action of a humid environment; in consequence, the instability of sulphides and sulpho-arsenides leads to the production of acid- and metal-rich leachates which pass incorporated into surface water or infiltrate through the land reaching groundwater. Electron microprobe analyses of pyrites confirm its high content of As (up to 10·11% As). Mining wastes stocked in the spoil heap present total As contents reaching up to 6·2%, and mine effluents and spoil heap leachates show As concentrations that can range from 1·4 to 9·2 mg/l. High concentrations of As have been detected too in stream sediments (up to 3·2%). In this context and on the basis of the risk assessment, proposals for remediation strategies are considered with the aim to reduce the leaching and transport of dissolved As from mining wastes. [ABSTRACT FROM AUTHOR]