Spatial and temporal variability of contaminants within estuarine sediments and native Olympia oysters: A contrast between a developed and an undeveloped estuary

Assessing the potential for a novel Composite Integrative Passive Sampler (CIPS) to investigate transboundary movement of organic chemicals in the Tijuana River Estuary

Nearly all environmental monitoring and research of chemical exposure in the aquatic environment relies on grab sampling of water and/or sediment providing only a snapshot in time. Passive sampling of water provides a more representative estimate of exposure compared to grab sampling, but current passive samplers have a limited working range of chemical properties. We tested a novel Composite Integrative Passive Sampler (CIPS) that simultaneously accumulates both hydrophobic and hydrophilic chemicals in water in the Tijuana River Estuary (TRE) on the U.S.-Mexico border. Quantitative targeted analysis detected 169 of the 193 targeted chemicals, and 128 of them were detected in all samples. These included polycyclic aromatic hydrocarbons, current-use and legacy organochlorine pesticides, polychlorinated biphenyls, plasticizers, pharmaceuticals, consumer product chemicals, stimulants, steroid hormones, haloacetic acids, and fecal sterols. The detected chemicals had a range of log KOW values from 0.2 to 8, by far the largest range ever reported for a passive sampler, and included both legacy chemicals and chemicals of emerging concern. Our findings are in stark contrast to previous work in the TRE, where very few organic pollutants were detected. We conclude the reason for this discrepancy is the ability of the CIPS to preconcentrate a very large range of chemicals in situ during deployment. The highest contaminant concentrations were closest to the U.S.-Mexico border. This work is the first demonstration of a passive sampler that can accumulate such a wide range of chemicals and strong evidence for transboundary movement of chemicals from Tijuana, Mexico to the US.

Emerging and legacy contaminants on the Brazilian southern coast (Santa Catarina): A multi-biomarker approach in oysters Crassostrea gasar (Adanson, 1757)

Coastal environments, such as those in the Santa Catarina State (SC, Brazil), are considered the primary receptors of anthropogenic pollutants. In this study, our objective was to evaluate the levels of emerging contaminants (ECs) and persistent organic pollutants (POPs) in indigenous Crassostrea gasar oysters from different regions of SC coast in the summer season (March 2022). Field collections were conducted in the São Francisco do Sul, Itajaí, Florianópolis and Laguna coastal zones. We analyzed the bioaccumulation levels of 75 compounds, including antibiotics (AB), endocrine disruptors (ED), non-steroidal anti-inflammatory drugs (NSAIDs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Furthermore, we assessed biomarker responses related to biotransformation, antioxidant defense, heat shock protection and oxidative damage in oysters' gills. Prevalence of ECs was observed in the central and southern regions, while the highest concentrations of POPs were detected in the central-northern regions of SC. Oysters exhibited an induction in biotransformation systems (cyp2au1 and cyp356a1, sult and GST activity) and antioxidant enzymes activities (SOD, CAT and GPx). Higher susceptibility to lipid peroxidation was observed in the animals from Florianópolis compared to other regions. Correlation analyses indicated possible associations between contaminants and environmental variables in the biomarker responses, serving as a warning related to climate change. Our results highlight the influence of anthropogenic activities on SC, serving as baseline of ECs and POPs levels in the coastal areas of Santa Catarina, indicating more critical zones for extensive monitoring, aiming to conserve coastal regions.

Seasonal profile of common pharmaceuticals in edible bivalve molluscs

Pharmaceuticals are recognised as environmental contaminants of emerging concern (CECs) due to their increasing presence in the aquatic environment, along with high bioactivity linked to their therapeutic use. Therefore, information on environmental levels is urgently required. This study examined the presence of a range of common pharmaceuticals in oysters and mussels intended for human consumption from England and Wales using stable isotope dilution tandem mass spectrometry. A range of compounds were detected in bivalve tissue, with the Selective Serotonin Reuptake Inhibitor antidepressant sertraline being most abundant, reaching a maximum concentration of 22.1 ng/g wet weight shellfish tissue. Levels of all pharmaceuticals showed seasonal and geographical patterns. A dietary risk assessment revealed that the levels of pharmaceuticals identified in bivalve molluscs represent a clear hazard, but not a risk for the consumer. This study highlights the requirement for further monitoring of the presence of pharmaceuticals and other CECs in bivalve molluscs.

Occurrence, distribution, source apportionment, ecological and health risk assessment of heavy metals in water, sediment, fish and prawn from Ojo River in Lagos, Nigeria

The study investigates the occurrence and bioaccumulation of heavy metals in water, sediment, fish, and prawn from the Ojo River with a view to identify the source of origin and the associated ecological and human health risks. The result shows that heavy metal concentrations in water [As = 0.010, Cd = 0.001, Cr = 0.041, Cu = 0.019, Co = 0.050, Fe = 0.099, Pb = 0.006, Ni = 0.003, and Zn = 0.452(mg/L)] were within the acceptable limits. The heavy metals in the sediment [As = 0.050, Cd = 0.287, Cr = 0.509, Cu = 0.207, Co = 0.086, Fe = 33.093, Pb = 0.548, Ni = 0.153 and Zn = 4.249 (mg/kg)] were within their respective background levels or earth's crust and the TEL and PEL standard limits. The bioaccumulation of heavy metals in fish and prawn tissues are in this hierarchical form: Fe > Zn > Cu > Cr > Ni > Co > Pb > Ar > Cd and Fe > Zn > Cu > Cr > Pb > Ar > Ni > Co > Cd, respectively. The bioaccumulation factors of heavy metals in fish ranged from 0.893 - 16.611 and 1.056 - 49.204 in prawn, which were higher than the biota-sedimentation factors (BSAF) values, inferring that the fish and prawns of this study ingested heavy metals highly from water column. The aggregated BSAF scores (fish = 5.584 and prawn = 9.137) showed that these organisms are good concentrators of heavy metals in sediments. The water quality index and other pollution indices (Single pollution index, Heavy metal assessment index, and Heavy metal pollution index) demonstrates slightly clean water, with a moderate level of contamination. The HI values of heavy metals in water, fish, and prawn were lower than 1, implying non-carcinogenic risk in children or adults. The ADD and EDI values of the metals were within their respective oral reference doses (RfD). The TCR values showed that exposure to water, either by ingestion or dermal absorption and the consumption of P. obscura and M. vollenhovenii from the Ojo River would not induce cancer risks in people, though As, Cr, Cd, and Pb showed carcinogenic potentials. The sediment contamination indices such as CF, mCd, EF, and Igeo showed a moderate level of pollution. The ecological risk values (NMPI, mCd = 0.068, PLI = 0.016, and R.I = 86.651) of heavy metals implies "no-moderate risk" except for Cd, which showed high risk. The ecotoxicological parameters,  m-PEL-Q (0.024) and m-ERM-Q (0.016) denotes low contamination and no probability of acute toxicity. The CV analysis showed high dispersions and variabilities in the distributions of the heavy metals in water. Other source analyses (Pearson's correlation matrix, PCA, and HCA) showed that both natural processes and anthropogenic activities are responsible for the occurrence of heavy metals in water and sediment from the Ojo River.

Mercury concentrations in sediments and oysters in a temperate coastal zone: a comparison of farmed and wild varieties

Oyster aquaculture has progressively increased to meet growing demands for seafood worldwide; however, its effects on methylmercury (MeHg) production in sediment and accumulation in oysters are largely unknown. In this study, total Hg (THg) and MeHg in sediments collected from aquaculture and reference sites and in farmed and wild oysters were measured and compared to explore potential factors that regulate MeHg production and bioaccumulation at the aquaculture sites. The results showed that the mean concentrations of THg and MeHg in varying sediment depths at the aquaculture site were 34 ± 4.1 ng g-1 and 16 ± 12 pg g-1, respectively. In comparison, the mean concentrations of THg and MeHg in sediments at the reference site were 25 ± 2.5 ng g-1 and 63 ± 28 pg g-1, respectively. While the MeHg/THg in the aquaculture sediments increased with organic carbon content, the slope of MeHg/THg versus organic carbon content was suppressed by high concentrations of dissolved sulfide in the pore water. Multiple parameters (total sulfur, total nitrogen and acid volatile sulfide in sediment, and dissolved sulfide in pore water) showed significant negative relationships with MeHg/THg in the sediment, and the total sulfur content in the sediment showed the highest inverse correlation factor with MeHg/THg (r =  - 0.83). The mean concentrations of THg and MeHg in farmed oysters (mean weight 3.2 ± 1.5 g) were 36 ± 10 ng g-1 and 15 ± 6.7 ng g-1, respectively, while those in wild oysters (mean weight 0.92 ± 0.32 g) were 47 ± 9.9 ng g-1 and 15 ± 6.7 ng g-1, respectively. Concerning oysters of the same size range, THg and MeHg levels were higher in farmed oysters than in wild oysters despite the faster growth rate of farmed oysters, suggesting that the Hg content of food sources is more important than growth dilution rates in the control of Hg levels. The mean hazardous quotient for MeHg in farmed oyster was calculated as 0.044 ± 0.020, suggesting no expected health risk from farmed oyster consumption.

Presence of pharmaceuticals and their metabolites in wild-living aquatic organisms - Current state of knowledge

In the last decades an increasing number of studies has been published concerning contamination of aquatic ecosystems with pharmaceuticals. Yet, the distribution of these chemical compounds in aquatic environments raises many questions and uncertainties. Data on the presence of selected pharmaceuticals in the same water bodies varies significantly between different studies. Therefore, since early 1990 s, wild organisms have been used in research on environmental contamination with pharmaceuticals. Indeed, pharmaceutical levels measured in biological matrices may better reflect their overall presence in the aquatic environments as such levels include not only direct exposure of a given organisms to a specific pollutant but also processes such as bioaccumulation and biomagnification. In the present paper, data concerning occurrence of pharmaceuticals in aquatic biota was reviewed. So far, pharmaceuticals have been studied mainly in fish and molluscs, with only a few papers available on crustaceans and macroalgae. The most commonly found pharmaceuticals both in freshwater and marine organisms are antibiotics, antidepressants and NSAIDS while there is no information about the presence of anticancer drugs in aquatic organisms. Furthermore, only single studies were conducted in Africa and Australia. Hence, systematization of up-to-date knowledge, the main aim of this review, is needed for further research targeting.

Variability of trace metals in coastal and estuary: Distribution, profile, and drivers

Ongoing global changes such as increasing sea-surface temperatures, decreasing acidity levels, and expanding oxygen-minimum zone may impact on the biogeochemical cycles of trace metals in ocean systems. Each trace metal has unique characteristics and a distinctive distribution pattern controlled by chemical, biological, and physical processes that occur in ocean systems. The correlations of variability drivers in trace metals are interesting topics for investigation. Following up on ocean research in the coastal and estuary area, we specifically review the distribution of trace metals in seawater and suspended and surface sediment. The marginal seas usually feature significant terrestrial inputs accompanied by several active water-mass currents. The purpose of this review is to provide an overview of variability related to trace-metal distribution in coastal and estuary systems and to specifically describe the distribution, profile and drivers that affect trace metals variability.

A Simple and Rapid Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Method for the Quantitation of Pharmaceuticals and Related Compounds in Mussels and Oysters

A simple, rapid ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed and optimized for the quantitation of a range of pharmaceuticals, metabolites, and related bioactive compounds in the bivalve mollusc species mussels (Mytilus edulis) and Pacific oysters (Crassostrea gigas). Shellfish tissues were extracted using a simple solvent-based extraction method prior to concentration and purification by pass-through solid-phase extraction and quantified using stable isotope dilution MS/MS. The analytes covered a range of therapeutic classes including antidepressants, anticonvulsants, beta-blockers, and antiplatelets. Of the 34 compounds included in the present study initially, 28 compounds were found to demonstrate acceptable performance. Performance was assessed by examining extraction efficiencies, matrix effects, sensitivity, and within- and between-batch precision. The results show that as indicated by acceptable HorRat and accuracy values, the method is fit for purpose. Application of this method to environmental mussel and oyster samples revealed the presence of 12 compounds at quantifiable concentrations, with the antidepressant sertraline being present at the highest level, reaching a concentration of 6.12 ng/g in mussel tissue. © 2021 Crown copyright. Environmental Toxicology and Chemistry 2021;40:3263-3274. © 2021 SETAC. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

Pharmaceuticals and alkylphenols in transplanted Pacific oysters (Crassostrea gigas): Spatial variation and growth effects

Pharmaceuticals and personal care products in wastewater discharge can be stressors to estuarine species. We transplanted juvenile Pacific oysters at varying distances within sites near wastewater treatment plant outfalls or oyster aquaculture control sites to assess small scale spatial variation in contaminant uptake and oyster condition. Oysters were transplanted to sites in Coos and Netarts Bays, Oregon and Grays Harbor, Washington, then collected after 9 and 12 months. Two pharmaceuticals (miconazole and virginiamycin M1) were detected in spring samples and four alkylphenols (NP1EO, NP2EO, NP and OP) were detected in summer samples, with more frequent detections at wastewater sites. Contaminant concentrations were similar across site types, indicating that even in sparsely populated coastal areas (<25,000 in the watershed), shellfish are exposed to and uptake wastewater contaminants. Additionally, oyster condition was lower at wastewater sites compared to aquaculture sites, indicating a need to better understand whether contaminant exposure affects oyster condition.

Analysis of the occurrence of microplastics in beach sand on the Brazilian coast

The occurrence of microplastics in coastal areas is a growing concern due to the increase in plastic waste pollution in recent decades. This study had as objective to evaluate the occurrence of microplastics in Brazilian beach sand, using a simple and fast methodology. In addition, possible microplastics were classified according to color, shape and chemical composition. The study was conducted on six beaches on the Brazilian coast: Pecado Beach (RJ), Castanheiras Beach (ES), Regência Beach (ES), Imbassaí Beach (BA), Viral Beach (SE) and Ponta dos Mangues Beach (SE). The methodology was adapted from international protocols, with section demarcation (100 m), where samples were collected from the superficial layer of the beach sand in ten quadrants (50 cm × 50 cm). The laboratory extraction procedure consisted of the density separation technique in two stages: the first used sodium chloride solution and the second used zinc chloride solution. For the visual inspection and screening procedures, a stereoscopic microscope was used. A total of 166 items of microplastics were collected on the six beaches on the Brazilian coast under study. The largest quantity of possible microplastics was recorded on the beaches of Viral (SE) and Ponta dos Mangues (SE) with 30.4 items/m² and 17.4 items/m², respectively. Regarding colour, white items were predominant (49.3%), and among particle types, fragments represented 85.1%. In addition, some microplastic particles were sent for FT-IR analysis, one of which was identified as being polyethylene. This study contributes to the knowledge of the presence of microplastics in different locations, and to supporting decision makers regarding coastal management.

Comparison of imidacloprid, propiconazole, and nanopropiconazole effects on the development, behavior, and gene expression biomarkers of the Pacific oyster (Magallana gigas)

Coastal areas are final recipients of various contaminants including pesticides. The effects of pesticides on non-target organisms are often unclear, especially at environmentally relevant concentrations. This study investigated the impacts of insecticide imidacloprid (IMI) and fungicide propiconazole (PRO), some of the most detected pesticides in the Arcachon Bay in France. This work also included the research of propiconazole nanoformulation (nanoPRO). The effects were assessed studying the development of the early life stages of the Pacific oyster (Magallana gigas). Oyster embryos were exposed for 24, 30, and 42 h (depending on the endpoint) at 24 °C to environmentally relevant concentrations of the two pesticides as well as to nanoPRO. The research focused on sublethal endpoints such as the presence of developmental malformations, alterations of locomotion patterns, or changes in the gene expression levels. No developmental abnormalities were observed after exposure to environmental concentrations detected in the Arcachon Bay in recent years (maximal detected concentration of IMI and PRO were 174 ng/L and 29 ng/L, respectively). EC₅₀ of PRO and nanoPRO were comparable, 2.93 ± 1.35 and 2.26 ± 1.36 mg/L, while EC₅₀ of IMI exceeded 200 mg/L. IMI did not affect larval behavior. PRO affected larval movement trajectory and decreased average larvae swimming speed (2 μg/L), while nanoPRO increased the maximal larvae swimming speed (0.02 μg/L). PRO upregulated especially genes linked to reactive oxygen species (ROS) production and detoxification. NanoPRO effects on gene expression were less pronounced - half of the genes were altered in comparison with PRO. IMI induced a strong dose-response impact on the genes linked to the detoxification, ROS production, cell cycle, and apoptosis regulation. In conclusion, our results suggest that current pesticide concentrations detected in the Arcachon Bay are safe for the Pacific oyster early development, but they might have a small direct effect via altered gene expressions, whose longer-term impacts cannot be ruled out.

Modeling the relationship between emerging and persistent organic contaminants in water, sediment and oysters from a temperate lagoon

The concentrations of emerging and persistent organic contaminants (EPOC) in oysters (C_O) from Aveiro Lagoon are represented as a function of their concentrations in water (C_W) and sediment (C_S) using linear and generalized additive models (LM, GAM). Additionally, four sampling seasons, octanol/water partition coefficients (K) and type of EPOC (pyrethroids, flame-retardants, musks, UV filters, polycyclic aromatic hydrocarbons, others) are included in the models. The probabilities of detection of EPOC in water, sediment and oysters are analyzed by GAM. The behavior of contaminants in water is determined by K with a clear seasonal trend. Sediments are reservoirs for hydrophobic compounds with less seasonal variation. Seasonal changes are found for C_O, the last being determined additively both by C_W and hydrophobicity from one side and by C_S and type of contaminants from the other side. The seasonal change of EPOC concentration in water, sediment and oysters is specific for each contaminant type.

Evaluating exposures of bay mussels (Mytilus trossulus) to contaminants of emerging concern through environmental sampling and hydrodynamic modeling

Bay mussels (Mytilus trossulus) were transplanted to 18 locations representing a range of potential exposures throughout Puget Sound, WA. Tissues were analyzed for over 200 organic contaminants. Results indicated the widespread exposure of marine organisms to trace levels of organic contaminants including the synthetic opioid oxycodone, present at three urban sites, and the chemotherapy drug melphalan, present at nine locations, at levels that may be of biological concern. Land-use and wastewater outfalls were evaluated as potential sources of CECs to the nearshore. Exposure to alkylphenol ethoxylates was associated with increased impervious surfaces in upland watersheds. A hydrodynamic simulation was performed using the Salish Sea Model to integrate inputs from 99 wastewater sources to Puget Sound. Predictions were consistent with concentrations of several wastewater-associated contaminants and δ¹⁵N enrichment. These results support the notion that Puget Sound nearshore biota suffer chronic exposures to a suite of contaminants from multiple sources and provide critical to focus future monitoring and management.

Metabolomic Investigations of the Temporal Effects of Exposure to Pharmaceuticals and Personal Care Products and Their Mixture in the Eastern Oyster (Crassostrea virginica)

The eastern oyster (Crassostrea virginica) supports a large aquaculture industry and is a keystone species along the Atlantic seaboard. Native oysters are routinely exposed to a complex mixture of contaminants that increasingly includes pharmaceuticals and personal care products (PPCPs). Unfortunately, the biological effects of chemical mixtures on oysters are poorly understood. Untargeted gas chromatography-mass spectrometry metabolomics was utilized to quantify the response of oysters exposed to fluoxetine, N,N-diethyl-meta-toluamide, 17α-ethynylestradiol, diphenhydramine, and their mixture. Oysters were exposed to 1 µg/L of each chemical or mixture for 10 d, followed by an 8-d depuration period. Adductor muscle (n = 14/treatment) was sampled at days 0, 1, 5, 10, and 18. Trajectory analysis illustrated that metabolic effects and class separation of the treatments varied at each time point and that, overall, the oysters were only able to partially recover from these exposures post-depuration. Altered metabolites were associated with cellular energetics (i.e., Krebs cycle intermediates), as well as amino acid metabolism and fatty acids. Exposure to these PPCPs also affected metabolic pathways associated with anaerobic metabolism, osmotic stress, and oxidative stress, in addition to the physiological effects of each chemical's postulated mechanism of action. Following depuration, fewer metabolites were altered, but none of the treatments returned them to their initial control values, indicating that metabolic disruptions were long-lasting. Interestingly, the mixture did not directly cluster with individual treatments in the scores plot from partial least squares discriminant analysis, and many of its affected metabolic pathways were not well predicted from the individual treatments. The present study highlights the utility of untargeted metabolomics in developing exposure biomarkers for compounds with different modes of action in bivalves. Environ Toxicol Chem 2020;39:419-436. © 2019 SETAC.

Persistent and emerging pollutants assessment on aquaculture oysters (Crassostrea gigas) from NW Portuguese coast (Ria De Aveiro)

The study aim was to determine a range of relevant persistent and emerging pollutants in oysters produced in an aquaculture facility located in an important production area, to assure their safety for human consumption. Pollutants, including 16 PAHs, 3 butyltins (BTs), 29 flame retardants (FRs, including organophosphate and halogenated FRs), 35 pesticides (including 9 pyrethroid insecticides) and 13 personal care products (PCPs, including musks and UV filters), were determined in oysters' tissues collected during one year in four seasonal sampling surveys. The seasonal environmental pollution on the production site was evaluated by water and sediment analysis. Furthermore, oysters' nutritional quality was also assessed and related with the consumption of healthy seafood, showing that oysters are a rich source of protein with low fat content and with a high quality index all year around. Results showed that most analysed pollutants were not detected either in oyster tissues or in environmental matrixes (water and sediments). The few pollutants detected in oyster tissues, including both regulated and non-legislated pollutants, such as a few PAHs (fluorene, phenanthrene, anthracene, fluoranthene, pyrene and indenopyrene), FRs (TPPO, TDCPP, DCP, BDE-47, BDE-209 and Dec 602) and PCPs (galaxolide, galaxolidone, homosalate and octocrylene), were present at low levels (in the ng/g dw range) and did not represent a significant health risk to humans. The observed seasonal variations related to human activities (e.g. tourism in summer) highlights the need for environmental protection and sustainable resource exploration for safe seafood production.

Spatial-temporal variability and transportation mechanism of polychlorinated biphenyls in the Yangtze River Estuary

Although the variability of polychlorinated biphenyls (PCBs) is strongly dependent on the hydro-sediment pattern, the quantification of this interaction is still not well described, especially for estuary areas. In this study, both chemical analyses and numerical simulation were conducted to explain the temporal-spatial variability and transportation mechanism of PCBs in the Yangtze River Estuary (YRE). The impacts of the upstream Three Gorges Dam (TGD) on estuarine PCBs were also addressed with a simulated scenario. The results showed that the PCBs levels in the YRE were relatively low or moderate and the highest levels were related to the maximum turbidity zone. The spatial variability of PCBs is strongly dependent on the hydrological circulation, which resulted in a declining trend from the inner YRE to the adjacent sea. The seasonal variability of PCBs could be due to the joint influence of the current and the erosion/deposition environment. The opposite temporal trends of the overlaying water and sediment are driven by the seasonal characteristics of hydro-sediment patterns. The simulated results also indicated that the distribution, fluxes and transport ability of PCBs in the South Branch changed as a result of the sediment discharge reduction after construction of the TGD.

Effects of pharmaceuticals and personal care products on marine organisms: from single-species studies to an ecosystem-based approach

Pharmaceuticals and personal care products (PPCPs) are contaminants of emerging concern that are increasing in use and have demonstrated negative effects on aquatic organisms. There is a growing body of literature reporting the effects of PPCPs on freshwater organisms, but studies on the effects of PPCPs to marine and estuarine organisms are limited. Among effect studies, the vast majority examines subcellular or cellular effects, with far fewer studies examining organismal- and community-level effects. We reviewed the current published literature on marine and estuarine algae, invertebrates, fish, and mammals exposed to PPCPs, in order to expand upon current reviews. This paper builds on previous reviews of PPCP contamination in marine environments, filling prior literature gaps and adding consideration of ecosystem function and level of knowledge across marine habitat types. Finally, we reviewed and compiled data gaps suggested by current researchers and reviewers and propose a multi-level model to expand the focus of current PPCP research beyond laboratory studies. This model includes examination of direct ecological effects including food web and disease dynamics, biodiversity, community composition, and other ecosystem-level indicators of contaminant-driven change.