Occurrence and dynamics of microplastics and emerging concern microparticles in coastal sediments: Impact of stormwater upgrade and port-associated facilities

Urban runoff is a significant source of microplastic pollution in aquatic environments, especially in coastal areas. Despite urban stormwater runoff being considered a major pathway of anthropogenic particles there's no studies about the impact of stormwater upgrades on microparticle transport. Moreover, due to the influence of anthropogenic activities, including maritime traffic and maintenance, on coastal environments, it is crucial to identify plastic debris from both inland and in-shore sources. This study evaluates characteristics, abundance, and distribution of microplastics in subtidal sediments from the southwestern Atlantic region, influenced by a recently upgraded stormwater outfall and port facilities. Herein, we have analyzed temporal trends, including seasonal dynamics and their relation with the pre- and post-upgrade of the stormwater outfall. Three main types of anthropogenic microparticles were observed: common plastic (MPs), paints (Pps), and tire wear particles (TWPs). Microparticle groups varied in morphology, color, and size distribution, including uncommon microparticle debris. Analysis by FTIR and Raman spectroscopies allows the identification of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, polyamide, and polyacrylonitrile polymers for MPs mainly. Pigments such as Naphthol AS, phthalocyanine, and quinacridone have been identified in Pps. SEM-EDS and FTIR analysis of collected TWPs revealed similar trace metals constituents and infrared signals to those observed in tire road samples. Spatial and temporal abundances of microparticle groups were significantly different (p < 0.05), mainly related to the distance from the stormwater outfall and seasons. TWPs showed the most significant seasonal increment rate among pre and post-upgrade periods. Furthermore, the upgrades made to the stormwater system have been observed to intensify the transport and increase the presence of specific anthropogenic microparticles in subtidal sediments. Based on these findings, the occurrence of TWPs emerges as a reliable urban runoff indicator to differentiate ex and in-situ sources in multipolluted coastal environments.

Stress responses to warming in the mussel Brachidontes rodriguezii (d'Orbigny, 1842) from different environmental scenarios

The intertidal mussel B. rodriguezii is a representative species from hard bottom substrates where both anthropogenic and natural stressors are present. Pre-exposure to these different stressors can modify the tolerance to additional stressors such as warming. Moreover, this tolerance can vary depending on intraspecific variables such as the organism's sex. The effects of warming and its intraspecific variability in representative coastal species are crucial to understanding the tolerance to future environmental scenarios. The mussels were collected in different environmental scenarios, including low (Control), chemical (Harbour) and natural stressed (Estuary) sites, and then exposed to different water temperatures (10-30 °C) for 14 days. Lethal and sublethal responses were evaluated in different mussel populations. Thus, cumulative death rate, air survival time, heat shock proteins (HSC70/HSP70), total ubiquitin, catalase (CAT), glutathione-s-transferase (GST) and lipid peroxidation (TBARS) were assessed in mussels from different areas and different sexes. The results revealed diminished air survival time and high cumulative mortality rate in mussels collected at the harbour and those exposed to higher temperatures, respectively. The sublethal responses of the field animals showed different patterns according to the different areas investigated. Besides, the results revealed that these differences were also observed between sexes. Regarding the sublethal responses in mussels exposed to warming, the interactive effects of temperature and sites showed a strong influence on all biochemical parameters analyzed (p < 0.001). Therefore, harbour mussels showed a distinct pattern compared to other locations and reflecting the most damaging effects of warming. The influence of sex and its interactions with warming were also crucial in most of the sublethal responses (p < 0.05). Multivariate analysis was performed with all sublethal responses, and the different warming scenarios showed different groups according to the sites. In the predicted warming scenarios, males showed no differences between sites. In contrast to males, females showed differences between sites in the predicted and the worse-case warming scenarios. Our results highlight the importance of compensatory mechanisms in the mussel warming tolerance like HSP70. The influence of sex is also crucial in understanding warming tolerance in mussels chronically exposed to pollutants in their natural environment. Also, lethal endpoints are essential for understanding the non-reversibility signature of the observed biochemical responses.

Spatio-temporal trends and body size differences of OCPs and PCBs in Laeonereis culveri (Polychaeta: Nereididae) from Southwest Atlantic estuaries

Southwest Atlantic (SWA) estuaries have been historically impacted by industrial and agricultural activities that represent an important source of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). Intraspecific differences in OCPs and PCBs levels were evaluated in the benthic polychaete Laeonereis culveri from SWA estuaries (Samborombón; Mar Chiquita; Quequén Grande and Bahía Blanca) at different spatio-temporal scales. Regarding inter- and intra-estuarine spatial comparisons polychaetes showed significant differences in OCPs/PCBs levels (p < 0.05) being DDTs, endosulfan, penta- and hexa-CBs homologues the most representative compounds. Intra-estuarine comparisons also showed significant differences in terms of seasonality and body size (p < 0.05). OCPs/PCBs concentrations were negatively correlated with animal weight, but this covariable was not relevant on differences observed. OCPs/PCBs levels in polychaetes showed strong relationships with those of sediments, being suitable for estuarine biomonitoring studies. Seasonal and body-size differences found in OCPs and PCBs levels in tissues reveal the importance of these factors for intra-estuarine monitoring.

Linking stable isotopes and biochemical responses in Balanus glandula under sewage influence

In the present study, we analyzed the influence of untreated sewage exposure on carbon (δ13C) and nitrogen (δ15N) isotopic composition and several biochemical responses in the barnacle Balanus glandula. The main objective was to evaluate whether changes in stable isotopes signature do reflect biochemical sub-lethal effects in a sewage influence gradient. Stable isotopes analysis showed differences in isotope signatures between close sewage influence and distant sites, being δ13C signatures stronger than that of δ15N. Regarding biochemical effects, although organisms close to the effluent would be clearly exposed to contaminants (increased GST activity) the oxidative stress would not be too evident (peroxidases and ACAP not affected). The most affected physiological aspect was the digestive one, reflected in increased alkaline proteases and lipases activities. A clear relation between δ15N and GST activity was found, showing to δ15N as an indicator of potential exposure to chemical contaminants.

Sublethal effects in Perinereis gualpensis (Polychaeta: Nereididae) exposed to mercury-pyrene sediment mixture observed in a multipolluted estuary

Sediment-living organisms can be subjected to a multi-pollution condition due to an increase in the diversity of contaminants. Sediment mixtures of Mercury (Hg) and some polycyclic aromatics hydrocarbons like Pyrene (Pyr) are common in heavily industrialized coastal zones. In the present study, greater than (>) and less than (<) probable effect concentration levels (PELs) of Hg and Pyr were assessed using spiked sediments in order to determine combined (Hg + Pyr) effects in uptake, metabolization and oxidative balance in the polychaete Perinereis gualpensis at short and medium-term exposure. Hg + Pyr significantly influenced the uptake/kinetics of Hg and Pyr metabolite 1-OH-pyrene in polychaete tissues during the exposure time compared with separate treatments of each analyte (p < 0.05). Both the Hg-only and Pyr-only exposures significantly influenced both enzymatic and non-enzymatic responses respect to control groups (p < 0.05). The Hg-only treatment showed the worst scenario related to the activation and subsequent inhibition of glutathione S- transferase (GST) and peroxidase (GPx) activities, high levels of Thiol-groups (SH-groups), low antioxidant capacity (ACAP) and enhanced lipid peroxidation (TBARS) in the last days of exposure (p < 0.05). In contrast, ragworms exposed to Hg + Pyr showed a significant increase in both enzymatic and non-enzymatic activity during the first days of exposure and the absence of lipid peroxidation during the whole experiment. Our results suggest different oxidative stress scenarios in P. gualpensis when exposed to >PEL Hg concentration with <PEL Pyr in sediments. Results also reveal the importance of the exposure time, endpoints involved as well as of the contaminant monitoring during the whole experiments in assessing the interactive effects of the contaminant mixture.

Uptake, metabolism and sub-lethal effects of BDE-47 in two estuarine invertebrates with different trophic positions

Two microcosm types -sediment-biota and biota-biota- were constructed to simulate different pathways of BDE-47 uptake, metabolism and oxidative stress effects in two key estuarine invertebrates (polychaete Laeonereis acuta and crab Cyrtograpsus angulatus). In the sediment-biota experiment, both species were exposed to spiked sediments; an environmentally reported and a high concentration of BDE-47 for 2 weeks. In the biota-biota experiment, crabs were fed with polychaetes pre-exposed to BDE-47 in the sediment-biota experiment. The sediment-biota experiment first revealed that polychaetes significantly accumulated BDE-47 (biota-sediment accumulation factor >2; p < 0.05) to a much greater extent than the crab organs (muscle, hepatopancreas, gills) at both sediment concentrations. For oxidative stress responses, polychaete and crab tissues exposed to spiked sediment showed a significant increase (p < 0.05) of only glutathione S-transferase (GST) activity with respect to controls in both BDE-47 concentrations. No lipid peroxidation (TBARS) or total antioxidant capacity (ACAP) changes were evident in the species or organs exposed to either BDE-47 sediment concentration. The biota-biota experiment showed that feeding crabs with pre-exposed polychaetes caused BDE-47 accumulation in organs as well as significant amounts of BDE-47 eliminated through feces (p < 0.05). Unlike the sediment-biota exposure, crabs fed with pre-exposed BDE-47 polychaetes showed the most conspicuous oxidative stress responses. Significant changes in GST and ACAP in both hepatopancreas and gills, in addition to enhanced TBARS levels in the hepatopancreas with respect to controls (p < 0.05), revealed that BDE-47 assimilated by invertebrates represents a potential source of toxicity to their predators. No methoxylated metabolites (MeO-PBDEs) were detected during BDE-47 metabolism in the invertebrates in either of the two different exposure types. In contrast, hydroxylated metabolites (OH-PBDEs) were detected in polychaetes and crab organs/feces in both experiments. Our results demonstrate that PBDE hydroxylation is one of the main biotransformation routes of BDE-47 in estuarine animals, which could be associated with the oxidative stress responses found.

Biochemical responses and physiological status in the crab Hemigrapsus crenulatus (Crustacea, Varunidae) from high anthropogenically-impacted estuary (Lenga, south-central Chile)

Estuarine environmental assessment by sub-individual responses is important in order to understand contaminant effects and to find suitable estuarine biomonitor species. Our study aimed to analyze oxidative stress responses, including glutathione-S-transferase (GST) activity, total antioxidant capacity (ACAP) and lipid peroxidation levels (TBARS) in estuarine crabs Hemigrapsus crenulatus from a high anthropogenically-impacted estuary (Lenga) compared to low and non-polluted estuaries (Tubul and Raqui), in a seasonal scale (winter-summer), tissue specific (hepatopancreas and gills) and sex related responses. Results showed that hepatopancreas in male crabs better reflected inter-estuary differences. Morpho-condition traits as Cephalothorax hepatopancreas index (CHI) could be used as an indicator of physiological status of estuarine crabs. Discriminant analysis also showed that GST and TBARS levels in summer are more suitable endpoints for establishing differences between polluted and non-polluted sites. These results suggest the importance of seasonality, target tissue, sex and physiological status of brachyuran crabs for estuarine biomonitoring assessment.

Biomonitoring of antioxidant and oxidative stress responses in Perinereis gualpensis (Polychaeta: Nereididae) in Chilean estuarine regions under different anthropogenic pressure

This study aimed to analyze oxidative stress parameters, including levels of the antioxidant glutathione (GSH), activity of glutamate-cysteine ligase (GCL) and glutathione-S-transferase (GST), total antioxidant capacity and protein oxidation, in the polychaete Perinereis gualpensis (Nereididae) collected from the Biobío, Itata, Valdivia and Lingue estuaries in Chile, which present different degrees of anthropogenic pressure. Sampling sites were characterized considering a geographic information system and the physicochemical characteristics of water and sediment. Significant differences (p<0.05) were observed between the sampling sites for most of the responses (GSH, GCL, GST and antioxidant capacity), mainly related to human activities such as agriculture, industry, among others. Multivariate correlation analysis indicates a certain relationship of antioxidant responses with human activities, salinity, and worm weight, this last employed to standardize GST and antioxidant capacity. These results clearly indicate biomarker responses in P. gualpensis in Biobío and Valdivia estuaries, the more affected by human activities.