Muscle concentrations of organochlorinated compounds as well as biliary levels of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APEs) were determined in two different fish species, the four-spotted megrim (Lepidorhombus boscii) and the pouting (Trisopterus luscus) collected along the Northern Iberian coast. Additionally, a set of biochemical markers namely, 7-ethoxyresorufin O-deethylase (EROD), UDP-glucuronosyltransferase (UGT) and catalase (CAT) were measured in liver subcellular fractions. Chemical analysis indicated geographical differences in pollutant loads that were further reinforced by biomarker responses. Thus, EROD activity showed a good correlation with the amount of PCBs bioaccumulated in muscle tissue of both fish species. Elevated UGT activity was observed in those individuals highly exposed to APEs and 1-naphthol. The study reinforces the need to select representative sentinel species from different habitats for biomonitoring purposes and provides further support for the use of biomarkers in assessing the health of coastal areas.

Birds can be impacted by pollution but are seldom used as bioindicators. One exception involves the Dippers Cinclus spp., a genus of five passerines adapted uniquely to swim and dive in rivers on five continents to feed on aquatic invertebrates and small fishes. Here, we review the effectiveness of Dippers as pollution indicators while identifying further opportunities, caveats and uncertainties that are transferable to other indicator organisms. Dippers have been used as biodindicators i) through relationships linking their distribution, breeding performance and behaviour to river pollution through effects on prey quality and quantity; ii) where contaminants occur in their eggs, tissues, faeces or regurgitates, notably metals (Hg, Se), persistent pollutants (e.g. PCBs, PBDEs, DDE, HEOD) and microplastics. Most data are from C. cinclus in Europe and C. mexicanus in North America. While some pollution effects on Dipper distribution or fitness are well-evidenced, particularly acidification, the resulting impairments are not sufficient to diagnose the source of impact without additional data on water quality or prey abundance. Dippers in these cases provide a general rather than definitive indication of pollution. For contaminants, Dippers have revealed the distribution of specific pollutants at scales ranging from point-sources and regions to different continents. Influences of land use, trophic pathways, diet-shifts, contaminant transport, intergenerational transfer and trends through time have all been identified and supported by detailed knowledge of prey use, territoriality, dispersal, migration, life history, isotopic signatures and energetics. We suggest opportunities to expand the role of Dippers as bioindicators into other locations (Asia and South America), other influences on water quality (e.g. agriculture, wastewater), other contaminants (e.g. PFAs, pharmaceuticals) and through developments in modern biology such as 'omics. Initial data also show that Dippers could integrate the effects on rivers of habitat modification, flow modification and climate change by indicating effects both directly and through interactions with other multiple stressors. This group of birds illustrates how fundamental ecological information aids the development of bioindicators but reveals the importance of using complementary environmental data when diagnosing bioindicator response. We suggest these are important lessons for ecological indicators more generally.

The number of published studies evaluating the effects of microplastics (MPs) in fish has increased in the last decade. However, of the available studies, few have explored the long-term effects of MPs on fish growth and reproduction and have resorted to MPs in the form of μm-sized beads/microspheres. In this study, 6-10 day-old post-hatch medaka (Oryzias latipes) fish were exposed to 50 (i.e. 1X) and 500 (i.e. 10X) μg of heterogeneously sized and irregularly shaped virgin polystyrene (PS) MP particles (200-μm range)/L for 150 days. These concentrations corresponded to respective daily mean values of 247 and 3087 particles/L administered through the diet. The PS MPs dietary exposure resulted in body burdens of 114 and 440 particles/g fish on day 50, and of 78 and 173 particles/g fish on day 100 since the respective exposures to the 1X and the 10X treatments started. The biometric analyses found no incidence of PS MPs ingestion on overall fish growth and development. The histological survey in the 10X group did not reveal alterations in gills or in the digestive tract. Mild alterations in other organs were seen and included increased fluid material in the peritoneal cavity, glomerular and tubular alterations in kidneys, and differences in the diameter of the thyroid follicles and thickness of the follicular epithelial cells. The initial days of the reproductive phase revealed MP-related differences in the number of gravid females, fecundity, and fertilization rates. Overall, these values reverted to normal rates throughout the succeeding days. No significant effects of PS MPs exposure were evidenced on offspring success. The 150-day PS MPs dietary exposure used in this study provided clues of histological effects and a reproduction delay. However, it did not seem to compromise overall growth/thriving and the ongoing reproduction.

Sulfide mining wastes may lead to severe environmental and human health risks. This study aims to use geochemical and ecotoxicological indicators for the assessment of the ecological risks of potentially toxic elements (PTEs) in the San Quintín mining group to categorize wastes prior to mining restoration. Ecotoxicity was evaluated using crustacean (Dahpnia magna, Thamnocephalus platyurus) and algae (Raphidocelis subcapitata) bioassays. The geochemical and mineralogical results suggested that the mining residues underwent intense weathering processes, with active processes of acidity generation and metal mobility. Total PTEs concentrations indicated that the mining materials were extremely polluted, with Pb, Zn and Cd geoaccumulation index (Igeo) values higher than 5 in more than 90% of the samples. The pollution load index (PLI) showed average values of 18.1, which classifies them as very highly polluted. The toxicity tests showed a higher toxicity for plants than crustaceans, being the highest values of toxicity related to toxic elements (Pb, Cd and Zn), electrical conductivity and to pH. This paper presents for the first time the combination of indices in the categorization of mining waste prior to its restoration. The combination of them has made it possible to categorize the waste and adapt the restoration and remediation procedures.

Recently, environment pollution around the globe has increased because of anthropogenic activities. As part of the biota, plants can assimilate the compounds present in air, water and soil and respond to changes in surround conditions, for that, they can be used as bioindicators of global pollution. However, urban plants' ability to monitor organic pollutants in air, soil, and water have not been profoundly studied yet. Anthropogenic contamination produced by five different types of pollutants [polycyclic aromatic hydrocarbons (PAHs), pharmaceuticals and personal care products (PPCPs), perfluoroalkyl substances (PFASs), pesticides and organophosphorus flame retardants (OPFRs)] has been studied in Riyadh and Abha areas (Saudi Arabia). In addition to the points in both cities, a control point located in the Asir National Park (close to Abha), which is little affected by human activity, was used. The 5 groups of contaminants were found with different but high detection frequencies from 85 % to 100 % in wild and ruderal plants. PAHs were detected in all the analyzed samples at the highest average sum of concentrations (ΣPAHs) 1486 ng·g−1 dry weight (d.w.). Statistically significant differences were obtained between Riyadh, Abha and the point located in the national park (p < 0.05). ΣPAHS in Riyadh >> ΣPAHs in Abha > ΣPAHs in the National Park. Values of the average sum of concentrations for the other groups of contaminants ΣPPCPs, ΣPFASs, Σpesticides and ΣOPFRs were 420.5, 171, 48 and 47 ng g−1 d.w., respectively. High values of PPCPs are due to the presence of salicylic acid. Differences in the average sum of each type of contaminant concentrations between cities were not statistically significant. The results of this assessment of wild and ruderal plants as bioindicators for 5 types of organic contaminants suggest that they can be used to monitor anthropogenic contaminants in the terrestrial environment.