Suitability of aquatic mosses for biomonitoring micro/meso plastics in freshwater ecosystems

Abstract Background Mesoplastics (5–25 mm) and microplastics (0.001–5 mm) are emerging pollutants of great concern. However, reliable methods of monitoring these types of plastic in river ecosystems have not yet been established. The goal of this work was to evaluate, for the first time, the suitability of Fontinalis antipyretica as a biomonitor of meso- and micro-plastics in rivers. With this aim, native samples of the moss and devitalized moss clones, held inside the bags, were compared for the uptake of fluorescent polystyrene particles under laboratory conditions, and for retention of plastic debris in the field, in sites close to wastewater treatment plants. Results In the laboratory experiment, the moss retained smaller microplastics, and a higher number of polystyrene meso and microplastics was counted in the moss bags than in the native moss. In the field study, the moss retained plastic debris chiefly in the form of fibres regardless of the capacity and flow rate of the wastewater treatment plants affecting each sampling site. The uniform morphology of moss clone seems to affect the retention of this type of pollutant. The FTIR analysis confirmed the particles entrapped by the moss bags as plastic, specifically polyethylene and polyamide type 6, among the most common plastic polymers detected in rivers. Conclusions The study findings highlighted the value of using uniform material, as the clone exhibited a greater accumulation efficiency with respect to the native moss. The mesh bags could act as selective filters and/or prevent the loss of adhering plastics. In the field, the bags favour plastic fibres retention despite the river flow. Finally, although FTIR is useful for the identification of plastic type, it is not very sensitive when small quantities of ground samples are used

Regional development gaps in Argentina: A multidimensional approach to identify the location of policy priorities

Spatial inequalities within Latin American countries have historically attracted the interest ofacademics, policy-makers, and international agencies. This article aims to provide amultidimensional diagnosis of provincial development gaps in Argentina, in order to identifythe location of policy priorities. Therefore, we built a large database, which covers sevendevelopment dimensions, and applied multivariate analysis techniques to overcome someanalytical limitations of previous studies. Results show the stability of provincial developmentgaps between 2003 and 2013 and some heterogeneity within geographic regions. Instead,cluster analysis offers a better classification of Argentine provinces according to theirdevelopment gaps, which can help the government to prioritize the places wheredevelopment policies are strategic.Fil: Niembro, Andrés Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universidad Nacional de Río Negro; ArgentinaFil: Sarmiento, Jesica Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universidad Nacional de Río Negro; Argentin

What dead seaweeds can tell us about metal uptake and their application to control marine pollution

The mechanisms of trace element uptake by seaweeds are still unknown, despite being key to understand the impact of pollution in coastal environments. This knowledge gap, in addition to the lack of standardization, have also hindered the use of seaweeds to monitor seawater pollution. To address these shortcomings, we tested the use of devitalization as a pre-exposure treatment for brown seaweed transplants, and we compared devitalized and fresh transplants to gain some insights into the mechanisms of element uptake. We exposed four types of Fucus vesiculosus transplants in 6 sites for 4, 8 and 20 days: fresh and devitalized (dried or boiled) algal segments held in mesh bags, and whole algal thalli imitating natural conditions. We then determined he concentrations of 11 trace elements in the algal tissues. The element concentrations were highest in the devitalized transplants, but the material lost consistency and weight throughout the exposure period, limiting their use to short periods. We proposed several factors that may contribute to the different accumulation patterns between treatments, and examined the implications for the uptake mechanisms, revealing that two of the most important are surface adsorption of sediment particles and chemical bounds to extracellular componentsThis study is part of the project PID2022–142802NB-I00 awarded by the Spanish Ministerio de Ciencia e Innovación. The authors belong to the Grupo de Referencia Competitiva GRC GI-1252/GPC2020–23 (ED431C 2020/19) which is co-funded by ERDF (EU). A. Vázquez-Arias is grateful to the Spanish Ministerio de Ciencia, Innovación y Universidades for a grant awarded within the Programa de Formacion de Profesorado Universitario (grant number FPU19/01989)S

Should moss samples used as biomonitors of atmospheric contamination be washed?

When terrestrial mosses are used to monitor atmospheric contamination, the samples are usually analysed without first being washed, so that the contaminants deposited on the moss can be quantified. However, when the aim is to evaluate phyto-toxic effects and the risks associated with increased concentrations of contaminants, it is the bioconcentrated fraction that is of interest. In such cases, the samples are washed to remove deposited material adhering to the surface of the moss. In the present study, the efficacy of the washing step was evaluated, by electron microscopy and microanalysis, in samples exposed to different levels of contamination. The results obtained show that washing is not effective at removing particles deposited on the moss surface, so that an alternative cleaning method is required. Until such a method becomes available, use of the Sequential Elution Technique is recommended for precise determination of the bioconcentrated contaminants

Evaluation of the efficacy of the sequentialelution technique, by use of electronmicroscopy methods

In the present study, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS) was used in conjunction with the sequential elution technique (SET) to evaluate the efficacy of extraction of Zn from the moss Pseudoscleropodium purum (Hedw.) M. Fleisch. Moss samples were collected from two areas, a contaminated area (with high concentrations of Zn) in the surroundings of a steel works, and an uncontaminated area. Some samples from the uncontaminated area were used as controls, and others were incubated in a solution of ZnCl2 for subsequent analysis of uptake and location of Zn. The concentrations of Zn in the different cell compartments of the moss were determined by use of the SET, and different points on the surface of the moss and in deposited particles were analysed by SEM–EDS. The results showed that the extracellular fraction obtained by SET includes the Zn bound to cation exchange sites in the moss and Zn bound to particles on the moss surface, which leads to overestimation of extracellular Zn. After extracellular extraction, Zn was not detected on the surface of the moss or in the particles. To avoid problems associated with the presence of particles on the moss surface, a washing procedure should be used to remove such particles before application of the SET. Another possibility is to use the intracellular concentration, as this is not affected by the metal load in the particles and better reflects those contaminants that affect the moss metabolism

Moss bag biomonitoring: a methodological review

Although the moss bag technique has been used for active biomonitoring for the past 40 years, there is still no standardized protocol that enables application of the technique as a tool to monitor air quality. The aim of this review paper is to evaluate the degree of standardization of each of the variables that must be considered in applying the technique (i.e. the variables associated with preparation of the moss and moss bags, exposure of the bags, and post-exposure treatment). For this purpose, 112 scientific papers that report the methods used in applying the moss bag technique were consulted. Finally, on the basis of the conclusions reached, we propose a protocol that will enable each of these variables to be investigated separately, with the final aim of developing a standardized methodolog

Levels of Antioxidant Compound Glutathione in Moss from Industrial Areas

Plants possess a wide range of cellular mechanisms that help them tolerate potentially toxic substances. Several studies that were carried out under laboratory conditions have demonstrated that the antioxidant compound glutathione plays a role in enabling mosses to tolerate high levels of heavy metals without toxic effects. However, until now, the antioxidant levels have not been studied in mosses under field conditions. In this study, we aimed to clarify the antioxidant concentrations of glutathione in the terrestrial moss Pseudoscleropodium purum growing in industrial environments characterised by high atmospheric levels of Cd, Ni, and Pb, and to evaluate the potential use of the compound as a biomarker. The results indicated the existence of a glutathione threshold response, which was significantly correlated with the metal toxicity and which may be influenced by metal bioavailability. Although future studies are needed to strengthen the findings, the present study suggests that total concentration of glutathione in P. purum could therefore be used as a biomarker in air pollution biomonitoring studies, provided that metal bioavailability is taken into account