Transcriptomic analysis reveals the endocrine toxicity of tributyltin and triphenyltin on the whelk Reishia clavigera and mechanisms of imposex formation.

Organotin compounds (OTs) are endocrine disruptors that induce imposex in hundreds of gastropods, but little is known about their underlying molecular mechanisms. This study aimed to investigate the endocrine toxicity and molecular responses to tributyltin (TBT) and triphenyltin (TPT) exposure in the whelk Reishia clavigera, which often serves as a biomonitor for OT contamination. Over a 120-day exposure to environmentally relevant concentrations of TBT (1000 ng L-1) and TPT (500 ng L-1), we observed a significant increase in penis length in both male and female whelks. Notably, TPT exhibited a stronger potency in inducing pseudo-penis development and female sterility, even at a half dose of TBT. Bioaccumulation analysis also revealed higher persistence and accumulation of TPT in whelk tissues compared to TBT. Differential expression analysis identified a substantial number of differentially expressed genes (DEGs), with TPT exposure eliciting more DEGs than TBT. Our results demonstrated that OTs induced xenobiotic metabolism and metabolic dysregulation in the digestive gland, impaired multiple cellular functions and triggered neurotoxicity in the nervous system, and disrupted lipid homeostasis and oxidative stress in the gonads. Furthermore, imposex was possibly associated with disturbances in retinoic acid metabolism, nuclear receptor signaling, and neuropeptide activity. When compared to TBT, TPT exhibited a more pronounced endocrine-disrupting effect, attributable to its higher bioaccumulation and substantial interruption of transcriptional regulation, OT detoxification, and biosynthesis of retinoic acids in R. clavigera. Our results, therefore, highlight the importance of considering the differences in bioaccumulation and molecular toxicity between TBT and TPT in future risk assessments of these contaminants. Overall, our study provided molecular insights into the toxicity and transcriptome profiles in R. clavigera exposed to TBT and TPT, shedding light on the endocrine-disrupting effects and reproductive impairment in female gastropods.

Stereoselective Bioconcentration and Neurotoxicity of Perfluoroethylcyclohexane Sulfonate in Marine Medaka.

Perfluoroethylcyclohexane sulfonate (PFECHS) is an emerging per- and polyfluoroalkyl substance used to replace perfluorooctane sulfonate (PFOS), mainly in aircraft hydraulic fluids. However, previous research indicates the potential neurotoxicity of this replacement chemical. In this study, marine medaka (Oryzias melastigma) was exposed to environmentally relevant concentrations of PFECHS (concentrations: 0, 0.08, 0.26, and 0.91 µg/L) from the embryonic stage for 90 days. After exposure, the brain and eyes of the medaka were collected to investigate the bioconcentration potential of PFECHS stereoisomers and their effects on the nervous systems. The determined bioconcentration factors (BCFs) of PFECHS ranged from 324 ± 97 to 435 ± 89 L/kg and from 454 ± 60 to 576 ± 86 L/kg in the brain and eyes of medaka, respectively. The BCFs of trans-PFECHS were higher than those of cis-PFECHS. PFECHS exposure significantly altered γ-aminobutyric acid (GABA) levels in the medaka brain and disrupted the GABAergic system, as revealed by proteomics, implying that PFECHS can disturb neural signal transduction like PFOS. PFECHS exposure resulted in significant alterations in multiple proteins associated with eye function in medaka. Abnormal locomotion was observed in PFECHS-exposed medaka larvae, which was rescued by adding exogenous GABA, suggesting the involvement of disrupted GABA signaling pathways in PFECHS neurotoxicity.

Aggravating Pollution of Emerging Aryl Organophosphate Esters in Urban Estuarine Sediments of South China.

Emerging aryl organophosphate esters (aryl-OPEs) have been employed as substitutes for organohalogen flame retardants in recent years; however, their environmental occurrence and associated impacts in urban estuarine sediments have not been adequately investigated, impeding regulatory decision-making. Herein, field-based investigations and modeling based on surface sediment and sediment core analysis were employed to uncover the historical pollution and current environmental impacts of aryl-OPEs in the Pearl River Estuary, South China. Our results revealed a substantial increase in aryl-OPE emission, particularly emerging aryl-OPEs, through sediment transport to the estuary since the 2000s. The emerging aryl-OPEs comprised 83% of the total annual input in the past decade, with an average annual input of 155,000 g. Additionally, the emerging-to-traditional aryl-OPE concentration ratios increased with decreasing distance from the shore, peaking in the highly urbanized riverine outlets. These findings indicate that inventories of emerging aryl-OPEs are likely increasing in estuarine sediments and their emissions are surpassing those of traditional aryl-OPEs. Our risk-based priority screening approach indicates that some emerging aryl-OPEs, particularly bisphenol A bis(diphenyl phosphate), can pose a higher environmental risk than traditional aryl-OPEs in estuarine sediments. Overall, our study highlights the importance of recognizing the environmental impacts of emerging aryl-OPEs.

Microplastics in Hong Kong's marine waters: Impact of rainfall and Pearl River discharge.

This study provided a systematic investigation of microplastics in Hong Kong's surface marine waters during the pandemic from 2019 to 2021. Microplastics (2.07 ± 4.00 particles/m3) exhibited significant temporal variations with higher abundance in the wet season, without a consistent trend after the mandatory mask-wearing requirement was announced. The impact of pandemic restrictions on microplastic distribution was found to be relatively minor. However, significant correlations between microplastic abundances and rainfall highlighted the substantial contribution of local emissions through surface runoff. Notably, sites in closer proximity to the Pearl River Delta exhibited higher microplastic abundances, indicating their association with emission sources. The influence of rainfall and adverse weather on marine microplastic loads demonstrated different sensitivities among various locations but can generally last for one month. These results revealed the impact of seasonal rainfall on coastal microplastics and emphasized the need for efforts to reduce microplastic discharge from land-based sources.

Global daily mask use estimation in the pandemic and its post environmental health risks: Analysis based on a validated dynamic mathematical model.

The outbreak of the COVID-19 pandemic led to a sharp increase in disposable surgical mask usage. Discarded masks can release microplastic and cause environmental pollution. Since masks have become a daily necessity for protection against virus infections, it is necessary to review the usage and disposal of masks during the pandemic for future management. In this study, we constructed a dynamic model by introducing related parameters to estimate daily mask usage in 214 countries from January 22, 2020 to July 31, 2022. And we validated the accuracy of our model by establishing a dataset based on published survey data. Our results show that the cumulative mask usage has reached 800 billion worldwide, and the microplastics released from discarded masks due to mismanagement account for 3.27% of global marine microplastic emissions in this period. Furthermore, we illustrated the response relationship between mask usage and the infection rates. We found a marginally significant negative correlation existing between the mean daily per capita mask usage and the rate of cumulative confirmed cases within the range of 25% to 50%. This indicates that if the rate reaches the specified threshold, the preventive effect of masks may become evident.

Impact of environmental factors changes induced by marine heatwaves and heavy precipitation on antibiotic toxicity to Isochrysis galbana: Implications for climate change adaptation.

Isochrysis galbana, a crucial primary producer and food source in aquatic ecosystems, faces increasing challenges from climate change and emerging contaminants like antibiotics. This study investigates the combined effects of sudden temperature increase (representing marine heatwaves) and rapid salinity change (representing extreme precipitation events) on the toxicity of tetracycline (TC) and oxytetracycline (OTC) to I. galbana. Short-term experiments reveal heightened antibiotic toxicity at 31 °C or salinities of 18 PSU, surpassing algal tolerance limits. Long-term tests show decreased inhibition of algal growth on day 9, indicating algal adaptation to the environment. Analyses of photosynthesis II efficiency, pigment content, and macromolecular composition support this, suggesting adaptation mechanism activation. While algae acclimate to the environment during long-term antibiotic exposure, extreme weather conditions may compromise this adaptation. These findings have implications for managing antibiotics in aquatic environments under climate change.

Risk assessment of e-waste - Liquid Crystal Monomers re-suspension caused by coastal dredging operations.

The Pearl River Estuary (PRE), one of the primary e-waste recycling centers in the world, has been suffering from the pollution of Liquid Crystal Monomers (LCMs), critical materials with persistent, bio-accumulative, and toxic substances used in electronic devices. It has been detected in seabed sediment with both high frequency and concentration near PRE - Hong Kong (HK) waters. In the same area, dredging operations with in-situ sediment have been frequently used in the last decades for coastal land reclamation projects. Dredging is known to cause a huge amount of sediment re-suspension into water columns, with potential damage to marine ecosystems and biodiversity. In this study, we proposed a new risk assessment strategy to estimate the secondary pollution due to the re-suspension sediment highly contaminated by LCMs. We formulate a robust and reliable probabilistic approach based on unsupervised machine learning and hydrodynamic and sediment transport numerical simulation. New risk indexes were also proposed to better quantify the impact of contaminated sediments. We applied the methodology to assess the potential impact of dredging operations in the PRE and Hong Kong waters on the local marine ecosystem. The results of the analysis showed how the potentially contaminated areas depended on the dredging locations.

Pharmaceutical Residues in Edible Oysters along the Coasts of the East and South China Seas and Associated Health Risks to Humans and Wildlife.

The investigation of pharmaceuticals as emerging contaminants in marine biota has been insufficient. In this study, we examined the presence of 51 pharmaceuticals in edible oysters along the coasts of the East and South China Seas. Only nine pharmaceuticals were detected. The mean concentrations of all measured pharmaceuticals in oysters per site ranged from 0.804 to 15.1 ng g-1 of dry weight, with antihistamines being the most common. Brompheniramine and promethazine were identified in biota samples for the first time. Although no significant health risks to humans were identified through consumption of oysters, 100-1000 times higher health risks were observed for wildlife like water birds, seasnails, and starfishes. Specifically, sea snails that primarily feed on oysters were found to be at risk of exposure to ciprofloxacin, brompheniramine, and promethazine. These high risks could be attributed to the monotonous diet habits and relatively limited food sources of these organisms. Furthermore, taking chirality into consideration, chlorpheniramine in the oysters was enriched by the S-enantiomer, with a relative potency 1.1-1.3 times higher when chlorpheniramine was considered as a racemate. Overall, this study highlights the prevalence of antihistamines in seafood and underscores the importance of studying enantioselectivities of pharmaceuticals in health risk assessments.

Genetic mechanisms of co-emergence of INH-resistant Mycobacterium tuberculosis strains during the standard course of antituberculosis therapy.

The incidence of isoniazid (INH) resistant Mycobacterium tuberculosis is increasing globally. This study aimed to identify the molecular mechanisms behind the development of INH resistance in M. tuberculosis strains collected from the same patients during the standard course of treatment. Three M. tuberculosis strains were collected from a patient before and during antituberculosis (anti-TB) therapy. The strains were characterized using phenotypic drug susceptibility tests, Mycobacterial Interspersed Repeated Unit-Variable-Number Tandem Repeats (MIRU-VNTR), and whole-genome sequencing (WGS) to identify mutations associated with INH resistance. To validate the role of the novel mutations in INH resistance, the mutated katG genes were electroporated into a KatG-deleted M. tuberculosis strain (GA03). Three-dimensional structures of mutated KatG were modeled to predict their impact on INH binding. The pre-treatment strain was susceptible to INH. However, two INH-resistant strains were isolated from the patient after anti-TB therapy. MIRU-VNTR and WGS revealed that the three strains were clonally identical. A missense mutation (P232L) and a nonsense mutation (Q461Stop) were identified in the katG of the two post-treatment strains, respectively. Transformation experiments showed that katG of the pre-treatment strain restored INH susceptibility in GA03, whereas the mutated katG genes from the post-treatment strains rendered negative catalase activity and INH resistance. The protein model indicated that P232L reduced INH-KatG binding affinity while Q461Stop truncated gene transcription. Our results showed that the two katG mutations, P232L and Q461Stop, accounted for the co-emergence of INH-resistant clones during anti-TB therapy. The inclusion of these mutations in the design of molecular assays could increase the diagnostic performance.IMPORTANCEThe evolution of drug-resistant strains of Mycobacterium tuberculosis within the lung lesions of a patient has a detrimental impact on treatment outcomes. This is particularly concerning for isoniazid (INH), which is the most potent first-line antimycobacterial drug. However, the precise genetic factors responsible for drug resistance in patients have not been fully elucidated, with approximately 15% of INH-resistant strains harboring unknown genetic factors. This raises concerns about the emergence of drug-resistant clones within patients, further contributing to the global epidemic of resistance. In this study, we revealed the presence of two novel katG mutations, which emerged independently due to the stress exerted by antituberculosis (anti-TB) treatment on a parental strain. Importantly, we experimentally demonstrated the functional significance of both mutations in conferring resistance to INH. Overall, this research sheds light on the genetic mechanisms underlying the evolution of INH resistance within patients and provides valuable insights for improving diagnostic performance by targeting specific mutations.

Metagenomics-Based Microbial Ecological Community Threshold and Indicators of Anthropogenic Disturbances in Estuarine Sediments.

Assessing the impacts of cumulative anthropogenic disturbances on estuarine ecosystem health is challenging. Using spatially distributed sediments from the Pearl River Estuary (PRE) in southern China, which are significantly influenced by anthropogenic activities, we demonstrated that metagenomics-based surveillance of benthic microbial communities is a robust approach to assess anthropogenic impacts on estuarine benthic ecosystems. Correlational and threshold analyses between microbial compositions and environmental conditions indicated that anthropogenic disturbances in the PRE sediments drove the taxonomic and functional variations in the benthic microbial communities. An ecological community threshold of anthropogenic disturbances was identified, which delineated the PRE sediments into two groups (H and L) with distinct taxa and functional traits. Group H, located nearshore and subjected to a higher level of anthropogenic disturbances, was enriched with pollutant degraders, putative human pathogens, fecal pollution indicators, and functional traits related to stress tolerance. In contrast, Group L, located offshore and subjected to a lower level of anthropogenic disturbances, was enriched with halotolerant and oligotrophic taxa and functional traits related to growth and resource acquisition. The machine learning random forest model identified a number of taxonomic and functional indicators that could differentiate PRE sediments between Groups H and L. The identified ecological community threshold and microbial indicators highlight the utility of metagenomics-based microbial surveillance in assessing the adverse impacts of anthropogenic disturbances in estuarine sediments, which can assist environmental management to better protect ecosystem health.

Degradation of organic UV filters in the water environment: A concise review on the mechanism, toxicity, and technologies.

Organic ultraviolet filters (OUVFs) have been used globally for the past 20 years. Given that OUVFs can be quickly released from sunscreens applied on human skins, they have been frequently detected in aquatic environments and organisms. Some byproducts of OUVFs might be more recalcitrant and toxic than their parent compounds. To further assess the toxicity and potential risk of OUVFs' byproducts, it is necessary to determine the fate of OUVFs and identify their transformation products. This review summarizes and analyzes pertinent literature and reports in the field of OUVFs research. These published research works majorly focus on the degradation mechanisms of OUVFs in aquatic environments, their intermediates/byproducts, and chlorination reaction. Photodegradation (direct photolysis, self-sensitive photolysis and indirect photolysis) and biodegradation are the main transformation pathways of OUVFs through natural degradation. To remove residual OUVFs' pollutants from aqueous environments, novel physicochemical and biological approaches have been developed in recent years. Advanced oxidation, ultrasound, and bio-based technologies have been proven to eliminate OUVFs from wastewaters. In addition, the disinfection mechanism and the byproducts (DBPs) of various OUVFs in swimming pools are discussed in this review. Besides, knowledge gaps and future research directions in this field of study are also mentioned.

Facet-Specific Photocatalytic Degradation of Extracellular Antibiotic Resistance Genes by Hematite Nanoparticles in Aquatic Environments.

The persistence of extracellular antibiotic resistance genes (ARGs) in aquatic environments has attracted increasing attention due to their potential threat to public health and the environment. However, the fate of extracellular ARGs in receiving water remains largely unknown. This study investigated the influence of hematite nanoparticles, a widespread natural mineral, on the photodegradation of extracellular ARGs in river water. Results showed that under exposure to visible light, hematite nanoparticles, at environmental concentrations, resulted in a 3-5 orders of magnitude reduction in extracellular ARGs. This photodegradation of extracellular ARGs is shown to be facet-dependent; the (001) facet of hematite demonstrates a higher removal rate than that of the (100) facet, which is ascribed to its enhanced adsorption capability and higher hydroxyl radical (•OH) production. Density functional theory (DFT) calculations corroborate this finding, indicating elevated iron density, larger adsorption energy, and lower energy barrier of •OH formation on the (001) facet, providing more active sites and •OH generation for extracellular ARG interaction. Gel electrophoresis and atomic force microscopy analyses further confirm that the (001) facet causes more substantial damage to extracellular ARGs than the (100) facet. These findings pave the way for predicting the photodegradation efficiency of hematite nanoparticles with varied facets, thereby shedding light on the inherent self-purification capacity for extracellular ARGs in both natural and engineered aquatic environments.

Serum Cholesterol and Impact of Age on Coronary Heart Disease Death in More Than 4 Million Veterans.

Background The lipid hypothesis postulates that lower blood cholesterol is associated with reduced coronary heart disease (CHD) risk, which has been challenged by reports of a U-shaped relation between cholesterol and death in recent studies. We sought to examine whether the U-shaped relationship is true and to assess the impact of age on this association. Method and Results We conducted a prospective cohort study of 4 467 942 veterans aged >18 years, with baseline outpatient visits from 2002 to 2007 and follow-up to December 30, 2018, in the Veterans Health Administration electronic health record system. We observed a J-shaped relation between total cholesterol (TC) and CHD mortality after a comprehensive adjustment of confounding factors: flat for TC <180 mg/dL, and greater risk was present at higher cholesterol levels. Compared with veterans with TC between 180 and 199 mg/dL, the multiadjusted hazard ratios (HRs) for CHD death were 1.03 (95% CI, 1.02-1.04), 1.07 (95% CI, 1.06-1.09), 1.15 (95% CI, 1.13-1.18), 1.25 (95% CI, 1.22-1.28), and 1.45 (95% CI, 1.42-1.49) times greater among veterans with TC (mg/dL) of 200 to 219, 220 to 239, 140 to 259, 260 to 279 and ≥280, respectively. Similar J-shaped TC-CHD mortality patterns were observed among veterans with and without statin use at or before baseline. Conclusions The cholesterol paradox, for example, higher CHD death in patients with a low cholesterol level, was a reflection of reverse causality, especially among older participants. Our results support the lipid hypothesis that lower blood cholesterol is associated with reduced CHD. Furthermore, the hypothesis remained true when TC was low due to use of statins or other lipid-lowering medication.

Safety and outcomes with efgartigimod use for acetylcholine receptor-positive generalized myasthenia gravis in clinical practice.

INTRODUCTION/AIMS: Multiple novel therapies have been approved for patients with myasthenia gravis. Our aim is to describe the early experience of efgartigimod use in acetylcholine receptor antibody-positive generalized myasthenia gravis (AChR+ve gMG). METHODS: This multicenter retrospective study included AChR+ve gMG patients from five major neuromuscular centers who were treated with efgartigimod and had both pre- and post-efgartigimod myasthenia gravis activities of daily living (MG-ADL) scores. Information regarding MG history, concomitant treatment(s), MG-ADL and other MG-specific measures, laboratory data, and adverse events were recorded. RESULTS: A total of 37 patients (M:23, F:14) with a mean age of 65.56 (±14.74) y were included in this cohort. A total of 36/37 patients completed at least one cycle and 28 patients completed at least two cycles of efgartigimod. A total of 72% (26/36) of patients had a clinically meaningful reduction (≥2 point change) in MG-ADL after the completion of the first cycle of efgartigimod (mean pre-efgartigimod 8.02) (±3.09) versus post-efgartigimod 4.33 (±3.62). Twenty-five percent (9/36) achieved minimal symptom expression status after one cycle and 25% (7/28) after the second cycle. Treatment benefit was sustained after cycle 2. Three out of four patients with thymoma in this cohort had clinically significant reductions in MG-ADL scores. Immunoglobulin G (IgG) levels decreased by about 60% (n = 10). One patient had a relapse of Clostridium difficile infection resulting in the discontinuation of therapy. Four patients had mild side effects. DISCUSSION: Efgartigimod led to clinically meaningful improvement in MG-ADL in diverse AChR+ve gMG patients but treatment frequency to achieve optimal symptom control needs to be explored.

Long-Read Sequencing with Hierarchical Clustering for Antiretroviral Resistance Profiling of Mixed Human Immunodeficiency Virus Quasispecies.

BACKGROUND: HIV infections often develop drug resistance mutations (DRMs), which can increase the risk of virological failure. However, it has been difficult to determine if minor mutations occur in the same genome or in different virions using Sanger sequencing and short-read sequencing methods. Oxford Nanopore Technologies (ONT) sequencing may improve antiretroviral resistance profiling by allowing for long-read clustering. METHODS: A new ONT sequencing-based method for profiling DRMs in HIV quasispecies was developed and validated. The method used hierarchical clustering of long amplicons that cover regions associated with different types of antiretroviral drugs. A gradient series of an HIV plasmid and 2 plasma samples was prepared to validate the clustering performance. The ONT results were compared to those obtained with Sanger sequencing and Illumina sequencing in 77 HIV-positive plasma samples to evaluate the diagnostic performance. RESULTS: In the validation study, the abundance of detected quasispecies was concordant with the predicted result with the R2 of > 0.99. During the diagnostic evaluation, 59/77 samples were successfully sequenced for DRMs. Among 18 failed samples, 17 were below the limit of detection of 303.9 copies/µL. Based on the receiver operating characteristic analysis, the ONT workflow achieved an F1 score of 0.96 with a cutoff of 0.4 variant allele frequency. Four cases were found to have quasispecies with DRMs, in which 2 harbored quasispecies with more than one class of DRMs. Treatment modifications were recommended for these cases. CONCLUSIONS: Long-read sequencing coupled with hierarchical clustering could differentiate the quasispecies resistance profiles in HIV-infected samples, providing a clearer picture for medical care.

Ocean Stratification Impacts on Dissolved Polycyclic Aromatic Hydrocarbons (PAHs): From Global Observation to Deep Learning.

Ocean stratification plays a crucial role in many biogeochemical processes of dissolved matter, but our understanding of its impact on widespread organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), remains limited. By analyzing dissolved PAHs collected from global oceans and marginal seas, we found different patterns in vertical distributions of PAHs in relation to ocean primary productivity and stratification index. Notably, a significant positive logarithmic relationship (R2 = 0.50, p < 0.05) was observed between the stratification index and the PAH stock. To further investigate the impact of ocean stratification on PAHs, we developed a deep learning neural network model. This model incorporated input variables determining the state of the seawater or the stock of PAHs. The modeled PAH stocks displayed substantial agreement with the observed values (R2 ≥ 0.92), suggesting that intensified stratification could prompt the accumulation of PAHs in the water column. Given the amplified effect of global warming, it is imperative to give more attention to increased ocean stratification and its impact on the environmental fate of organic pollutants.

Legacy and Emerging Per- and Polyfluoroalkyl Substances Surveillance in Bufo gargarizans from Inlet Watersheds of Chaohu Lake, China: Tissue Distribution and Bioaccumulation Potential.

Amphibians are sensitive biomonitors of environmental pollutants but reports regarding per- and polyfluoroalkyl substances (PFAS), a class of synthetic organofluorine substances, are limited. In this study, samples of water and Chinese toads (Bufo gargarizans) were collected in Chaohu Lake, China. Tissue-specific bioaccumulation characteristics of 39 PFAS, including 19 perfluoroalkyl acids (PFAAs), 8 emerging PFAS, and 12 PFAA precursors, were investigated, and the levels of some biochemical indicators were determined. The highest PFAS concentrations were found in the liver [215.97 ng/g dry weight (dw)] of Chinese toads, followed by gonads (135.42 ng/g dw) and intestine (114.08 ng/g dw). A similar tissue distribution profile was found between legacy and emerging PFAS in the toads, and the occurrence of two emerging PFAS, 2,3,3,3-tetrafluoro-2-propanoate (HFPO-DA) and 6:2 hydrogen-substituted polyfluorooctane ether sulfonate (6:2 H-PFESA) in the amphibians were for the first time reported. Field-based bioaccumulation factors of HFPO-DA were higher than perfluorooctanoic acid, indicating the higher bioaccumulation potential of this emerging PFAS than the legacy C8 compound. Males had significantly higher gonad PFAS levels than females while estradiol levels in gonads increased with increasing concentrations of certain PFAS (e.g., 6:2 H-PFESA), implying that PFAS may trigger estrogenic effects in the toads, especially for male toads.

New Perspective to Understand and Prioritize the Ecological Impacts of Organophosphate Esters and Transformation Products in Urban Stormwater and Sewage Effluents.

Due to their prevalence in urban contaminated water, the driving factors of organophosphate esters (OPEs) need to be well examined, and their related ecological impacts should include that of their transformation products (TPs). Additionally, a robust framework needs to be developed to integrate multiple variables related to ecological impacts for improving the ecological health assessment. Therefore, OPEs and TPs in urban stormwater and wastewater in Hong Kong were analyzed to fill these gaps. The results revealed that the total concentrations of OPEs in stormwater were positively correlated with the area of transportation land. Individual TP concentrations and the mass ratios of individual TPs/OPEs were somewhat higher in sewage effluents than that in stormwater. OPEs generally showed relatively higher risk quotients than TPs; however, the total risk quotients increased by approximately 38% when TPs were factored in. Moreover, the molecular docking results suggested that the investigated TPs might cause similar endocrine disruption in marine organisms as their parent OPEs. This study employed the Toxicological-Priority-Index scheme to successfully integrate the ecological risks and endocrine-disrupting effects to refine the ecological health assessment of the exposure to OPEs and their TPs, which can better inform the authority on the prioritization for regulating these contaminants of emerging concern in urban built environments.

Temporal Trends and Suspect Screening of Halogenated Flame Retardants and Their Metabolites in Blubbers of Cetaceans Stranded in Hong Kong Waters during 2013-2020.

Halogenated flame retardants (HFRs) are a large class of chemical additives intended to meet flammability safety requirements, and at present, they are ubiquitous in the environment. Herein, we conducted the target analysis and suspect screening of legacy and novel HFRs and their metabolites in the blubber of finless porpoises (Neophocaena phocaenoides; n = 70) and Indo-Pacific humpback dolphins (Sousa chinensis; n = 35) stranded in Hong Kong, a coastal city in the South China Sea, between 2013 and 2020. The average concentrations of total target HFRs (ΣHFRs) were 6.48 × 103 ± 1.01 × 104 and 1.40 × 104 ± 1.51 × 104 ng/g lipid weight in porpoises and dolphins, respectively. Significant decreasing temporal trends were observed in the concentrations of tetra-/penta-/hexa-bromodiphenyl ethers (tetra-/penta-/hexa-BDEs) in adult porpoises stranded from 2013-2015 to 2016-2020 (p < 0.05), probably because of their phasing out in China. No significant difference was found for the concentrations of decabromodiphenyl ether and hexabromocyclododecane, possibly due to their exemption from the ban in China until 2025 and 2021, respectively. Eight brominated compounds were additionally identified via suspect screening. A positive correlation was found between the concentrations of tetra-BDE and methyl-methoxy-tetra-BDE (Me-MeO-tetra-BDE) (p < 0.05), indicating that the metabolism of tetra-BDE may be a potential source of Me-MeO-tetra-BDE in marine mammals.