Priority and emerging micropollutants distribution from coastal to continental slope sediments: A case study of Capbreton Submarine Canyon (North Atlantic Ocean)

Synthetic musks in the natural environment: Sources, occurrence, concentration, and fate-A review of recent developments (2010-2023)

Synthetic musks (SMs) have served as cost-effective substitutes for natural musk compounds in personal care and daily chemical products for decades. Their widespread use has led to their detection in various environmental matrices, raising concerns about potential risks. Despite numerous studies on SM levels in different natural environments, a systematic review of their contemporary presence is lacking. This review aims to address this gap by summarising recent research developments on SMs in diverse natural environments, including river water, lake water, seawater, estuarine water, groundwater, snow, meltwater, sediments, aquatic suspended matter, soils, sands, outdoor air, and atmospheric particulate matter. Covering the period from 2010 to 2023, the review focuses on four SM categories: nitro, polycyclic, macrocyclic, and alicyclic. It systematically examines their sources, occurrences, concentrations, spatial and temporal variations, and fate. The literature reveals widespread detection of SMs in the natural environment (freshwater and sediments in particular), with polycyclic musks being the most studied group. Both direct (e.g., wastewater discharges) and indirect (e.g., human recreational activities) sources contribute to SM presence. Levels of SMs vary greatly among studies with higher levels observed in certain regions, such as sediments in Southeast Asia. Spatial and temporal variations are also evident. The fate of SMs in the environment depends on their physicochemical properties and environmental processes, including bioaccumulation, biodegradation, photodegradation, adsorption, phase exchange, hydro-dilution effects. Biodegradation and photodegradation can decrease SM levels, but may produce more persistent and eco-toxic products. Modelling approaches have been employed to analyse SM fate, especially for indirect processes like photodegradation or long-distance atmospheric transport. Future studies should further investigate the complex fate if SMs and their environmental influence. This review enhances understanding of SM status in the natural environment and supports efforts to control environmental contamination.

A critical review of distribution, toxicological effects, current analytical methods and future prospects of synthetic musks in aquatic environments

Synthetic musks (SMs) have gained widespread utilization in daily consumer products, leading to their widespread dissemination in aquatic environments through various pathways. Over the past few decades, the production of SMs has consistently risen, prompting significant concern over their potential adverse impacts on ecosystems and human health. Although several studies have focused on the development of analytical techniques for detecting SMs in biological samples and cosmetic products, a comprehensive evaluation of their global distribution in diverse aquatic media and biological matrices remains lacking. This review aims to provide an up-to-date overview of the occurrence of SMs in both aquatic and various biological matrices, investigating their worldwide distribution trends, assessing their ecological toxicity, and comparing different methodologies for processing and analysis of SMs. The findings underscore the prevalence of polycyclic musks as predominant SMs, with consumption of various products in different countries leading to contrasting distribution of contaminants. Furthermore, the migration of SMs from sediments to the water phase is investigated, indicating the role of solid-phase reservoirs. Incomplete degradation of SMs in the environment could contribute to their accumulation in aquatic systems, impacting the growth and oxidative stress of aquatic organisms, and having a possibility of genotoxicity to them. Human exposure data highlight substantial risks for vulnerable populations such as pregnant women and infants. Moreover, contemporary methods for SMs analysis are presented in this review, particularly focusing on advancements made in the last five years. Finally, research enhancement and critical questions regarding the analysis of SMs are provided, offering suggestions for future research endeavors.

Stressors of emerging concern in deep-sea environments: microplastics, pharmaceuticals, personal care products and deep-sea mining

Although most deep-sea areas are remote in comparison to coastal zones, a growing body of literature indicates that many sensitive ecosystems could be under increased stress from anthropogenic sources. Among the multiple potential stressors, microplastics (MPs), pharmaceuticals and personal care products (PPCPs/PCPs) and the imminent start of commercial deep-sea mining have received increased attention. Here we review recent literature on these emerging stressors in deep-sea environments and discuss cumulative effects with climate change associated variables. Importantly, MPs and PPCPs have been detected in deep-sea waters, organisms and sediments, in some locations in comparable levels to coastal areas. The Atlantic Ocean and the Mediterranean Sea are the most studied areas and where higher levels of MPs and PPCPs have been detected. The paucity of data for most other deep-sea ecosystems indicates that many more locations are likely to be contaminated by these emerging stressors, but the absence of studies hampers a better assessment of the potential risk. The main knowledge gaps in the field are identified and discussed, and future research priorities are highlighted to improve hazard and risk assessment.

Characterization of micropollutants in urban stormwater using high-resolution monitoring and machine learning

Urban rainfall events can lead to the runoff of pollutants, including industrial, pesticide, and pharmaceutical chemicals. Transporting micropollutants (MPs) into water systems can harm both human health and aquatic species. Therefore, it is necessary to investigate the dynamics of MPs during rainfall events. However, few studies have examined MPs during rainfall events due to the high analytical expenses and extensive spatiotemporal variability. Few studies have investigated the occurrence patterns of MPs and factors that influence their transport, such as rainfall duration, antecedent dry periods, and variations in streamflow. Moreover, while there have been many analyses of nutrients, suspended solids, and heavy metals during the first flush effect (FFE), studies on the transport of MPs during FFE are insufficient. This study aimed to identify the dynamics of MPs and FFE in an urban catchment, using high-resolution monitoring and machine learning methods. Hierarchical clustering analysis and partial least squares regression (PLSR) were implemented to estimate the similarity between each MP and identify the factors influencing their transport during rainfall events. Eleven dominant MPs comprised 75% of the total MP concentration and had a 100% detection frequency. During rainfall events, pesticides and pharmaceutical MPs showed a higher FFE than industrial MPs. Moreover, the initial 30% of the runoff volume contained 78.0% of pesticide and 50.1% of pharmaceutical substances for events W1 (July 5 to July 6, 2021) and W6 (August 31 to September 1, 2021), respectively. The PLSR model suggested that stormflow (m³/s) and the duration of antecedent dry hours (h) significantly influenced MP dynamics, yielding the variable importance on projection scores greater than 1.0. Hence, our findings indicate that MPs in urban waters should be managed by considering FFE.

Soil physiochemical properties and bacterial community changes under long-term polycyclic aromatic hydrocarbon stress in situ steel plant soils

In situ soils were collected at two depths in Jinan and Hangzhou steel plants, which both have a long history of operation and polycyclic aromatic hydrocarbons (PAHs) contamination. The richness of 16 S rRNA gene and bacterial community of the soil were determined by real-time PCR and high-throughput sequencing. Soil physicochemical properties, PAHs contamination characteristics, and their interrelationships were also analyzed. In general, the PAHs contamination decreased with increasing soil depths. The physicochemical properties and PAH concentration of soil had synergistic impacts on the composition of the bacterial community. The long-term higher PAHs stress in Hangzhou contaminated soil (982 mg kg^-1) increased the bacterial abundance and diversity, while that of Jinan contaminated soil (63 mg kg^-1) decreased bacterial abundance and diversity. The pH value, sand content of the soil were positively correlated (P < 0.05) with the bacterial diversity including Simpson, Shannon, Observed_species and Chao1 indexes., and the other soil properties exhibited negative correlations with different strengths. The abundances of Curvibacter, Pseudomonas, Thiobacillus, Lysobacter, and Limnobacter were positively correlated with the PAHs concentration (P < 0.01). Additionally, the network structure of the PAHs-contaminated soils was more complex compared to that of uncontaminated soils, with stronger linkages and correlations between the different bacteria. These findings provide a theoretical basis for microbial remediation of PAHs-polluted soil.

Keystone microbial taxa organize micropollutant-related modules shaping the microbial community structure in estuarine sediments

The fluctuation of environmental conditions drives the structure of microbial communities in estuaries, highly dynamic ecosystems. Microorganisms inhabiting estuarine sediments play a key role in ecosystem functioning. They are well adapted to the changing conditions, also threatened by the presence of pollutants. In order to determine the environmental characteristics driving the organization of the microbial assemblages, we conducted a seasonal survey along the Adour Estuary (Bay of Biscay, France) using 16S rRNA gene Illumina sequencing. Microbial diversity data were combined with a set of chemical analyses targeting metals and pharmaceuticals. Microbial communities were largely dominated by Proteobacteria (41 %) and Bacteroidota (32 %), showing a strong organization according to season, with an important shift in winter. The composition of microbial communities showed spatial distribution according to three main areas (upstream, middle, and downstream estuary) revealing the influence of the Adour River. Further analyses indicated that the microbial community was influenced by biogeochemical parameters (C_org/N_org and δ¹³C) and micropollutants, including metals (As, Cu, Mn, Sn, Ti, and Zn) and pharmaceuticals (norfloxacin, oxolinic acid and trimethoprim). Network analysis revealed specific modules, organized around keystone taxa, linked to a pollutant type, providing information of paramount importance to understand the microbial ecology in estuarine ecosystems.

Microbial Diversity, Community Turnover, and Putative Functions in Submarine Canyon Sediments under the Action of Sedimentary Geology

Sampling challenges in deep-sea ecosystems lead to a lack of knowledge about the distribution of microbes in different submarine canyons. To study microbial diversity and community turnover under different ecological processes, we performed 16S/18S rRNA gene amplicon sequencing for sediment samples from a submarine canyon in the South China Sea. Bacteria, archaea, and eukaryotes made up 57.94% (62 phyla), 41.04% (12 phyla), and 1.02% (4 phyla) of the sequences, respectively. Thaumarchaeota, Planctomycetota, Proteobacteria, Nanoarchaeota, and Patescibacteria are the five most abundant phyla. Heterogeneous community composition was mainly observed in vertical profiles rather than horizontal geographic locations, and microbial diversity in the surface layer was much lower than that in deep layers. According to the null model tests, homogeneous selection dominated community assembly within each sediment layer, whereas heterogeneous selection and dispersal limitation dominated community assembly between distant layers. Different sedimentation processes of sediments, i.e., rapid deposition caused by turbidity currents or slow sedimentation, seem to be primarily responsible for these vertical variations. Finally, functional annotation through shotgun-metagenomic sequencing found that glycosyl transferases and glycoside hydrolases are the most abundant carbohydrate-active enzyme categories. The most likely expressed sulfur cycling pathways include assimilatory sulfate reduction, the link between inorganic and organic sulfur transformation, and organic sulfur transformation, while the potentially activated methane cycling pathways include aceticlastic methanogenesis and aerobic and anaerobic oxidation of methane. Overall, our study revealed high levels of microbial diversity and putative functions in canyon sediments and the important influence of sedimentary geology on microbial community turnover between vertical sediment layers. IMPORTANCE Deep-sea microbes have received growing attention due to their contribution to biogeochemical cycles and climate change. However, related research lags due to the difficulty of collecting samples. Based on our previous study, which revealed the formation of sediments under the dual action of turbidity currents and seafloor obstacles in a submarine canyon in the South China Sea, this interdisciplinary research provides new insights into how sedimentary geology influences microbial community assembly in sediments. We proposed some uncommon or new findings, including the following: (i) microbial diversity was much lower on the surface than in deeper layers (ii) archaea and bacteria dominated the surface and deep layers, respectively; (iii) sedimentary geology played key roles in vertical community turnover; and (iv) the microbes have great potential to catalyze sulfur, carbon, and methane cycling. This study may lead to extensive discussion of the assembly and function of deep-sea microbial communities in the context of geology.

Pharmaceutical pollution of hospital effluents and municipal wastewaters of Eastern Canada

Quantification of drugs residues in wastewaters of different sources could help better understand contamination pathways, eventually leading to effluent regulation. However, limited data are available for hospital-derived wastewaters. Here, an analytical method based on automated on-line solid-phase extraction liquid chromatography tandem mass spectrometry (on-line SPE - UPLC-MS/MS) was developed for the quantification of multi-class pharmaceuticals in wastewaters. Filtrate phase and suspended solids (SPM) were both considered to evaluate the distribution of targeted analytes. Experimental design optimization involved testing different chromatographic columns, on-line SPE columns, and loading conditions for the filtrate phase, and different organic solvents and cleanup strategies for suspended solids. The selected methods were validated with suitable limits of detection, recovery, accuracy, and precision. A total of 30 hospital effluents and 6 wastewater treatment plants were sampled to evaluate concentrations in real field-collected samples. Certain pharmaceuticals were quantified at high levels such as caffeine at 670,000 ng/L in hospital wastewaters and hydroxyibuprofen at 49,000 ng/L in WWTP influents. SPM samples also had high contaminant concentrations such as ibuprofen at 31,000 ng/g in hospital effluents, fluoxetine at 529 ng/g in WWTP influents or clarithromycin at 295 ng/g in WWTP effluents. Distribution coefficients (K_d) and particle-associated fractions (Φ) indicate that pharmaceuticals tend to have better affinity to suspended solids in hospital wastewater than in municipal wastewaters. The results also bring arguments for at source treatment of these specific effluents before their introduction into urban wastewater systems.

Sorption of Polycyclic Musks on Soil Components of Different Aggregate Sizes: The Effect of Organic Matter-Mineral Interactions

Polycyclic musks (PCMs) in soils have been of increasing concern because of their potential characteristics of persistence, bioaccumulation, and ecological risk. However, little is known about their fate process in soil environment. Here, two PCMs namely galaxolide (HHCB) and tonalide (AHTN) were selected as sorbates to explore their sorption process in soils. Sorption batch experiments with six soils and their different aggregate fractions were carried out to elucidate the effect of organic matter-mineral interactions in different aggregate fractions on sorption of these two PCMs. The possible causes of variation in the organic carbon-normalized partition coefficient (K_oc) for HHCB and AHTN have been investigated. The strong influence of organic matter-mineral interactions on K_oc was evidenced by the large variation in K_oc on HF-treatment for both bulk soils and their different aggregate fractions. This study verified the dual effect of organic matter-mineral interactions among selected soils, and in promoting or inhibiting sorption may be related to the types of organic matter-mineral interactions. There were also interactions between soil components with different aggregate sizes, which affected the variation of K_oc in the bulk soil. This study represents a valuable contribution to the understanding of the fate processes and behaviors of HHCB and AHTN in soils and its implication on the risk assessment.

Challenging the highstand-dormant paradigm for land-detached submarine canyons

Sediment, nutrients, organic carbon and pollutants are funnelled down submarine canyons from continental shelves by sediment-laden flows called turbidity currents, which dominate particulate transfer to the deep sea. Post-glacial sea-level rise disconnected more than three quarters of the >9000 submarine canyons worldwide from their former river or long-shore drift sediment inputs. Existing models therefore assume that land-detached submarine canyons are dormant in the present-day; however, monitoring has focused on land-attached canyons and this paradigm remains untested. Here we present the most detailed field measurements yet of turbidity currents within a land-detached submarine canyon, documenting a remarkably similar frequency (6 yr^-1) and speed (up to 5-8 ms^-1) to those in large land-attached submarine canyons. Major triggers such as storms or earthquakes are not required; instead, seasonal variations in cross-shelf sediment transport explain temporal-clustering of flows, and why the storm season is surprisingly absent of turbidity currents. As >1000 other canyons have a similar configuration, we propose that contemporary deep-sea particulate transport via such land-detached canyons may have been dramatically under-estimated.

Effects of bottom trawling on trace metal contamination of sediments along the submarine canyons of the Gulf of Palermo (southwestern Mediterranean)

Submarine canyons are preferential pathways for transport of particulate matter and contaminants from the shelf to the deep sea. The Gulf of Palermo continental margin has a very narrow shelf (about 2-3 km wide on average) and is incised by several submarine canyons that favour shelf-slope sediment transfer. A sediment core collected on the outer shelf and six sediment cores taken at different depths along the Oreto, Eleuterio and Anerella submarine canyons were analysed to study the transfer and historical record of trace metal contamination in the Gulf of Palermo continental margin. Trace metals, major elements, organic carbon and sediment grain size were analysed in these cores, which were dated with ²¹⁰Pb to assess their historical compositional evolution since the late 19th century. Hg, Pb, Cu, Zn and Cd content increased until the 1970s and 1980s, associated with the increase in urbanization and industrial activities in the Palermo area, and Hg was the contaminant that reached the highest enrichments. However, the increasing trend of these metals contamination was reversed in the 1970s and 1980s, coinciding with drastic changes in the terrigenous content and grain size of sediments in the canyon axes. These changes occurred when bottom trawling fleets expanded to deeper fishing grounds equipped with powerful trawlers around the Gulf of Palermo canyon heads and flanks and along the Oreto canyon axis. Bottom trawlers have resuspended large amounts of sediment, which have been transferred into the canyons since the 1970s and 1980s and have thus increased sediment accumulation rates. This resuspended sediment has been mixing with the sediment transferred and accumulated along the canyons, diluting and reducing its trace metal contamination levels since the expansion of the bottom trawling fleets.

Occurrence, sources, and risk assessment of unconventional polycyclic aromatic compounds in marine sediments from sandy beach intertidal zones

This study investigated the concentrations of polycyclic aromatic compounds (PACs), including parent polyaromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives, in 48 sediment samples from the intertidal region of sandy beaches in Baía de Todos os Santos (BTS), Salvador, State of Bahia, Brazil. The total PAH (∑PAH) concentration, total nitro-PAH (∑nitro-PAH) concentration, and total oxy-PAH (∑oxy-PAH) concentration ranged from 2.11 μg g^-1 dry weight (dw) to 28.0 μg g^-1 dw, 2.58 μg g^-1 dw to 30.2 μg g^-1 dw, and 0.34 μg g^-1 dw to 3.65 μg g^-1 dw, respectively. Elevated concentrations of parent PAHs and nitro-PAHs were found in samples from two sites in BTS, which were also characterized by high percentages of fine-medium sand and low organic matter contents. Potent mutagenic 3-nitrobenzanthrone (3-NBA) was found in 86% of the samples at concentrations ranging from 0.200 μg g^-1 dw to 0.690 μg g^-1 dw. Furthermore, calculations of the benzo[a]pyrene toxicity equivalency (BaPTEQ) indicated that three carcinogenic high-molecular-weight PAHs accounted for 98.7% of the total maximum PAH concentration. Finally, we assessed the possible environmental risks posed to benthic species living in the sediments of BTS. The results showed that the risk quotient for PAHs (RQ_PAHs) was ≥1. In turn, the summed RQ for all PACs (∑RQ_mixture) ranged from 1 to 30, but did not exceed the maximum allowable threshold; thus, the risks posed to benthic species were moderate for all sediment samples.

Organic contaminants in marine sediments and seawater: A review for drawing environmental diagnostics and searching for informative predictors

Marine ecosystems represent major sinks for persistent organic pollutants (POPs). Yet, while their regulations fit localized activity and emissions, POPs are mobile and can persist away from their source. The present review draws an environmental diagnostic of the organic substances studied over the past forty months, which ones accumulated the most, and where. Maximum reported concentration was used as a proxy for the accumulation of contaminants. POPs occurrences studied in the Jan 2018-April 2021 period were recorded into a database, along with (i) the geographical location of the sample and its coastal or offshore origin, (ii) the type of compartment analyzed (water vs sediment), as well as (iii) the POPs and the sample physical-chemical parameters reported. In the articles reviewed, maximum reported concentrations of POPs were in the ng/L range in seawater and in the μg/kg range in sediments. Some hotspots presented concentrations high enough to represent a hazard for sea organisms in the water columns (μg/L range) or in surficial sediments (mg/kg range). On a global scale, offshore (>1 km from the coast) maximum reported concentrations were, for the majority of the POPs, equivalent or higher than coastal ones. Finally, a POP solubility threshold (900 mg/L) was observed above which POPs would not be found in offshore waters, but only in sediments. This review highlights that studying POP accumulation away from their sources is fundamental for the diagnostic of long-lasting marine POPs contaminations. Further, POPs lipophilicity is a good predictor for offshore transport, and an indicator of interest for predicting sediment accumulation. Although POPs fate and transport in oceans is complex and require a finer analysis that this review could provide, the present work is a step forward identifying the hotspots in which POPs could be of particular concern, along with chemical indicators to predict for POPs accumulation in marine reservoirs.

Distributions of microplastics and larger anthropogenic debris in Norfolk Canyon, Baltimore Canyon, and the adjacent continental slope (Western North Atlantic Margin, U.S.A.)

Anthropogenic debris has been reported in all studied marine environments, including the deepest parts of the sea. Finding areas of accumulation and methods of transport for debris are important to determine potential impacts on marine life. This study analyzed both sediment cores and Remotely Operated Vehicle video to determine the density and distribution of debris, including both micro- and macroplastics, in Norfolk and Baltimore canyons. The average microplastic density in Norfolk Canyon sediment was 37.30 plastic particles m^-2 within the canyon and 21.03 particles m^-2 on the adjacent slope, suggesting that microplastics could accumulate within submarine canyons. In video transects from both Norfolk and Baltimore canyons, the largest amounts of macroplastic were recorded near the canyon heads. Our findings contribute to a growing evidence base that canyons and their associated benthic invertebrate communities are important repositories and conduits for debris to the deep sea.

Metals and metalloids in green turtle hepatic tissue (Chelonia mydas) from Santos Basin, Brazil

Metal and metalloid concentrations in the liver tissue of green turtles (Chelonia mydas) stranded on the Brazilian coast (n = 506) were studied using inductively coupled plasma mass spectrometry and cold vapor atomic fluorescence spectrometry. The influences of occurrence registers (date and location) and biological characteristics (sex, age, and developmental stage) were assessed, as well as the temporal influences of oil exploration and production activities. The mean concentrations of Cd, Cu, Mn, Zn, and Hg were the highest reported for the liver of C. mydas on the Brazilian coast. The mean element concentrations followed the order: Cu > Zn > Cd > Mn > As > Hg > Mo > Pb > V > Ni > Ba > Cr. Further, significant differences (p < 0.05) were observed for Hg between the sexes (males > females) and for As, Cu, Pb, Mo, and V between young individuals and older individuals (≥11 years), suggesting a relationship between the dietary shift inherent to green turtle development. These results were corroborated by the curved carapace length (CCL) data, wherein individuals residing in coastal areas (CCL > 50 cm) presented higher concentrations of Cu, Pb, Mo, Zn, Ba, and V than those in the oceanic stage (CCL < 30 cm). The opposite pattern was observed for As and Hg. The influences of spatial autocorrelation (Moran Index) at a global scale and oil production activities on the element concentrations were not observed. However, five hotspots of high metal concentrations were identified via a local spatial autocorrelation (local indicator of spatial association), existing predominantly in a region of heavy anthropic activity within the sampling area. Further, baseline element concentrations were established at the 95% confidence level. Overall, the developmental stage, which is related to feeding habits, had an expressive influence on element concentrations.

Organic pollutants in deep sea: Occurrence, fate, and ecological implications

The deep sea - an oceanic layer below 200 m depths - has important global biogeochemical and nutrient cycling functions. It also receives organic pollutants from anthropogenic sources, which threatens the ecological function of the deep sea. In this Review, critically examined data on the distribution of organic pollutants in the deep sea to outline the role of biogeochemical and geophysical factors on the global distribution and regional chemodynamics of organic pollutants in the deep sea. We found that the contribution of deep water formation to the influx of perfluorinated compounds reached a maximum, following peak emission, faster in young deep waters (< 10 years) compared to older deep waters (> 100 years). For example, perfluorinated compounds had low concentrations (< 10 pg L^-1) and vertical variations in the South Pacific Ocean where the ocean currents are old (< 1000 years). Steep geomorphologies of submarine canyons, ridges, and valleys facilitated the transport of sediments and associated organic pollutants by oceanic currents from the continental shelf to remote deep seas. In addition, we found that, even though an estimated 1.2-4.2 million metric tons of plastic debris enter the ocean through riverine discharge annually, the role of microplastics as vectors of organic pollutants (e.g., plastic monomers, additives, and attached organic pollutants) in the deep sea is often overlooked. Finally, we recommend assessing the biological effects of organic pollutants in deep sea biota, large-scale monitoring of organic pollutants, reconstructing historical emissions using sediment cores, and assessing the impact of deep-sea mining on the ecosystem.

Emerging Contaminants in Seafront Zones. Environmental Impact and Analytical Approaches

Some chemical substances have the potential to enter the coastal and marine environment and cause adverse effects on ecosystems, biodiversity and human health. For a large majority of them, their fate and effects are poorly understood as well as their use still unregulated. Finding effective and sustainable strategies for the identification of these emerging and/or anthropogenic contaminants that might cause polluting effects in marine environments to mitigate their adverse effects, is of utmost importance and a great challenge for managers, regulators and researchers. In this review we will evaluate the impact of emerging contaminants (ECs) on marine coastal zones namely in their ecosystems and biodiversity, highlighting the potential risks of organic pollutants, pharmaceuticals and personal care products. Emerging microextraction techniques and high-resolution analytical platforms used in isolation, identification and quantification of ECs will be also reviewed.

Pharmaceuticals in the marine environment: What are the present challenges in their monitoring?

During the last years, there has been a growing interest in the research focused on the pharmaceutical residues in the environment. Those compounds have been recognized as a possible threat to aquatic ecosystems, due to their inherent biological activity and their "pseudo-persistence". Their presence has been relatively few investigated in the marine environment, though it is the last receiver of the continental contamination. Thus, pharmaceuticals monitoring data in marine waters are necessary to assess water quality and to allow enhancing future regulations and management decisions. A review of the current practices and challenges in monitoring strategies of pharmaceuticals in marine matrices (water, sediment and biota) is provided through the analysis of the available recent scientific literature. Key points are highlighted for the different steps of marine waters monitoring as features to consider for the targeted substance selection, the choice of the marine site configuration and sampling strategies to determine spatio-temporal trends of the contamination. Some marine environment specific features, such as the strong dilution occurring, the complex hydrodynamic and local logistical constraints are making this monitoring a very difficult and demanding task. Thus key knowledge gap priorities for future research are identified and discussed. Suitable passive samplers to monitor pharmaceutical seawater levels need further development and harmonization. Non-target analysis approaches would be promising to understand the fate of the targeted molecules and to enhance the list of substances to analyze. The implementation of integrated monitoring through long-term ecotoxicological tests on sensitive marine species at environmental levels would permit to better assess the ecological risk of these compounds for the marine ecosystems.

Synthetic musk fragrances in sediments from a subtropical river-lake system in eastern China: occurrences, profiles, and ecological risks

Synthetic musk fragrances (SMFs) in aquatic environments have been of increasing concern because of their potential characteristic of persistent, bioaccumulated, and ecological harm. However, little is known about the distribution of SMFs in river-lake systems. In this study, the occurrence and risks of six SMFs measured in sediments from Lake Chaohu (eastern China) and the rivers flowing into it were investigated. The total sedimentary SMF concentrations ranged from 2.43 to 15.5 ng/g in Lake Chaohu (median = 5.17 ng/g), and 2.34-104 ng/g in the rivers (median = 10.6 ng/g). Overall, moderate levels of SMFs were found in comparison with previous results from other areas. Galaxolide and tonalide dominated in the rivers whereas cashmeran was dominant in Lake Chaohu. A source assessment indicated that the discharge from industries contributed importantly to the pollution of SMFs in the studied waters, in addition to the inputs from domestic sewage. Our estimates suggested that the current sedimentary SMF concentrations were likely to pose extremely low ecological risk to aquatic organisms. However, more studies are needed to focus on the spatial and temporal trends in distribution as well as the ecotoxicological implications of SMFs in the Lake Chaohu area because there is a general lack of relevant information.

Microbial degradation of hydrophobic emerging contaminants from marine sediment slurries (Capbreton Canyon) to pure bacterial strain

Despite emerging contaminants (ECs) are more and more monitored in environmental matrices, there is still a lack of data in marine ecosystems, especially on their fate and degradation potentials. In this work, for the first time, the degradation potential of synthetic musks (galaxolide and tonalide), UV filters (padimate O and octocrylene) and a pharmaceutical compound (carbamazepine) was studied in marine sediment samples, under laboratory conditions using sediment slurry incubations under biotic and abiotic conditions. Minimum half life times under biotic conditions were found at 21 days, 129 days and 199 days for padimate O, galaxolide and carbamazepine, respectively. Enrichments conducted under anoxic and oxic conditions demonstrated that degradations after one month of incubation either under both biotic and abiotic conditions were limited under anoxic conditions compared to oxic conditions for all the contaminants. Novel aerobic bacteria, able to degrade synthetic musks and UV filters have been isolated. These novel strains were mainly related to the Genus Bacillus. Based on these results, the isolated strains able to degrade such ECs, can have a strong implication in the natural resilience in marine environment, and could be used in remediation processes.

Removal of Pharmaceutical Micropollutants with Integrated Biochar and Marine Microalgae

Using microalgae to remove pharmaceuticals and personal care products (PPCPs) micropollutants (MPs) have attracted considerable interest. However, high concentrations of persistent PPCPs can reduce the performance of microalgae in remediating PPCPs. Three persistent PPCPs, namely, carbamazepine (CBZ), sulfamethazine (SMT) and tramadol (TRA), were treated with a combination of Chaetoceros muelleri and biochar in a photobioreactor during this study. Two reactors were run. The first reactor comprised Chaetoceros muelleri, as the control, and the second reactor comprised Chaetoceros muelleri and biochar. The second reactor showed a better performance in removing PPCPs. Through the response surface methodology, 68.9% (0.330 mg L-1) of CBZ, 64.8% (0.311 mg L-1) of SMT and 69.3% (0.332 mg L-1) of TRA were removed at the initial concentrations of MPs (0.48 mg L-1) and contact time of 8.1 days. An artificial neural network was used in optimising elimination efficiency for each MP. The rational mean squared errors and high R2 values showed that the removal of PPCPs was optimised. Moreover, the effects of PPCPs concentration (0-100 mg L-1) on Chaetoceros muelleri were studied. Low PPCP concentrations (<40 mg L-1) increased the amounts of chlorophyll and proteins in the microalgae. However, cell viability, chlorophyll and protein contents dramatically decreased with increasing PPCPs concentrations (>40 mg L-1).

Persistent organic pollutants (POPs) and personal care products (PCPs) in the surface sediments of a large tropical bay (Todos os Santos Bay, Brazil)

The occurrence and spatial distribution of persistent organic pollutants (POPs) and personal care products (PCPs) were investigated in surface sediments of Todos os Santos Bay. Samples were Soxhlet-extracted and analyzed by gas chromatography coupled with tandem mass spectrometry. Quantification limits (QL) ranged from 0.0025 ng g^-1 for POPs to 0.25 ng g^-1 for PCPs. Of the POPs studied, only PCBs and DDTs were detectable, with concentrations ranging from <QL to 4.66 ng g^-1, with increased concentrations near urban and industrial areas. PCPs ranged from <QL to 27.5 ng g^-1 and presented a homogeneous spatial distribution, probably related to the continuous inputs of these compounds from diffuse sources. Mean contaminant inventories ranged from 0.33 ± 0.23 ng cm^-2 for DDTs to 8.3 ± 8.4 ng cm^-2 for fragrances. To the best of our knowledge, this is the first study on the occurrence of UV filters in sediments from Brazilian coastal environments.