Tonalide Research Articles

Revealing the distribution of synthetic musks in Chinese estuarine sediments driven by natural and anthropogenic factors

Synthetic musks (SMs) commonly used in personal care products can accumulate in the estuarine environment, but influencing factors on their distribution at large-scale region remain largely unexplored. Herein, surface sediment samples from 18 main estuaries of China and two river outlets in the Yangtze River Estuary were collected to discern the spatial and temporal variations of SMs. Moreover, fourteen influencing factors consisting of natural and anthropogenic parameters were scrutinized and their significance were analyzed by using Spearman’s rank correlation and Random Forest. The widespread distribution of SMs were observed in Chinese estuarine sediments with the levels ranging from < reporting limit to 28 ng g-1 on a basis of dry weight (mean: 3.5 ng g-1). Predominated polycyclic musks shared similar sources both spatially and temporally. Positive correlation was found between SMs and total organic carbon in sediments, whereas the SM distribution was strongly influenced by regional anthropogenic activities. Regional population density was the primary influencing factor, followed by gross domestic product per unit area and wet deposition of particulate matters. A good correlation between SMs and water quality category indicated SMs could serve as an indicator for water quality. To the best of our knowledge, this is the first study to identify the main influencing factors on SM distribution in estuarine sediments, aiming to better understand the distribution and fate of emerging organic chemicals in the estuarine environment.

Binding Mechanism of Nitro Musks to Human Lactoferrin: Multispectral Approach, Docking and Molecular Dynamics Simulation.

Nitro musks are highly bioaccumulative and potentially carcinogenic, commonly used as additives in fabric softeners, detergents, and other household products. Furthermore, these substances have been detected in breast milk and human adipose tissue, posing a risk of direct exposure to pregnant women and infants. Human lactoferrin (HLF) is abundant in colostrum, and plays an important role in the non-specific immune system of the human body. In this study, the mechanisms of action of two nitro musk compounds, typical examples of synthetic musks, with HLF were investigated using molecular docking, dynamics simulation and multispectral methods. The fluorescence findings demonstrated that nitro musks quenched the intrinsic fluorescence of human lactoferrin through static quenching. Thermodynamic analysis of the binding parameters suggested that hydrophobic interactions acted synergistically in the formation of the complex. Moreover, analyses utilizing multispectral techniques, such as Fourier transform infrared (FTIR) spectroscopy, validated that the microenvironment and structure of HLF were altered in the presence of nitro musks. Finally, molecular docking and molecular dynamics simulations were employed to explore the specific binding mode of nitro musks with HLF and to assess the stability of the complex. These findings may provide a reference for assessing health risks to pregnant women and infants.

Enhanced human activities since 20th century in pearl river delta, southern China: Evidence from high-resolution sedimentary records of polycyclic aromatic hydrocarbons and synthetic musks

To understand the environmental impact of anthropogenic activities, the high-resolution temporal and compositional variations of polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs, and synthetic musks, related to human activities were investigated in a sediment core taken from the Pearl River Estuary, southern China. The temporal trend of the target compounds was evidence of the considerable impact of anthropogenic activities in the Pearl River Delta. Two significant increases of the target compounds levels in the sediment core were aligned with two nodes of key periods of economic development in China, namely, the foundation of People's Republic of China (1950s) and China's accession to the World Trade Organization (2000s). Subsequently, the significant decline of the target compounds in sediments from the 2010s indicated the successful regulation of pollutant discharges and pollution control measures. The increase in the contribution of higher molecular weight PAHs suggested a potential transition from agricultural activities to industrial activities.

Natural Musk and Synthetic Musk Analogues

Natural Musk and Synthetic Musk Analogues

Occurrence, Spatial Distribution, and Bioaccumulation of Dissolved Synthetic Musks in Freshwaters across China.

Commercial chemicals, such as synthetic musks, are of global concern, but data on their occurrence and spatial distribution in aquatic environments of large scale are scarce. Two sampling campaigns were conducted in the present study to measure freely dissolved synthetic musks in freshwaters across China using passive samplers, along with biological coexposure at selected sites. Polycyclic musks (PCMs) dominated synthetic musks, with a detection frequency of 95%. Higher concentrations of PCMs were observed in densely populated Mid, East, and South China compared to less populated regions, indicating the significance of anthropogenic activities for synthetic musks in water. The concentration ratios of galaxolide (HHCB)/tonalide (AHTN) were significantly higher in low-latitude areas than in high-latitude areas from June to September, suggesting that solar radiation played an important role in the degradation of HHCB/AHTN. Significant correlations were found between dissolved concentrations of HHCB and AHTN and their lipid-normalized concentrations in coexposed fish and clam. The estimated hazard quotients for HHCB and AHTN in freshwater fish consumed by humans were less than 0.01 at all sampling sites except the Yangtze River Basin. These results help to understand the environmental fate and ecological risks of synthetic musks on a large geographical scale.

Insights into bacterial resistance to contaminants of emerging concerns and their biodegradation by marine bacteria

Contaminants of Emerging Concern (CECs) are human-made chemicals that remain unregulated. The continuous detection of CECs in aquatic ecosystems, due to their incomplete removal, emphasizes the importance of understanding their fate and impact on the environment and human health. The detrimental effects of CECs on marine eukaryotes are well documented in multiple studies. However, their impact on marine bacteria and their biodegradation by these organisms are not well understood. In this study, two marine bacteria, Priestia sp. 35 ODPABA G14 and Rhodococcus sp. 23 AHTN G14, previously isolated from submarine sediments, were used. These two strains were tested for their resistance as well as their capacity to degrade different classes of hydrophobic and hydrophilic CECs, including synthetic musks, UV filters, pesticides and pharmaceuticals. Both strains showed high resistance to all of the hydrophobic tested CECs even up to 500 mg L−1. Only Ketoprofen was toxic to bacterial cells, particularly to Rhodococcus sp. starting at concentration as low as 4 mg L−1. Furthermore, Priestia sp. and Rhodococcus sp. strains exhibited high biodegradation potential, especially for hydrophobic compounds. Although this may not apply to all pollutants, the data presented in this study suggest a positive correlation between marine bacterial resistance to CECs and their high biodegradation potentials.

Assessing Contributions of Synthetic Musk Compounds from Wastewater Treatment Plants to Atmospheric and Aquatic Environments.

The high environmental concentrations, persistence, and toxicity of synthetic musk compounds (SMCs) necessitate a better grasp of their fate in wastewater treatment plants (WWTPs). To investigate the importance of WWTPs as pathways of SMCs to the environment, air and wastewater samples were collected at four WWTPs in Ontario, Canada. Polycyclic musks (PCMs) were present at higher concentrations than nitro musks (NMs) and macrocyclic musks (MCMs). Three PCMs [galaxolide (HHCB), tonalide (AHTN), and iso-E super (OTNE)] were the most abundant compounds (0.30-680 ng/m3 in air, 0.40-15 μg/L in influent, and 0.007-6.0 μg/L in effluent). Analyses of multiyear data suggest that risk management measures put in place have been effective in reducing the release of many SMCs into the environment. The highest removal efficiency, up to almost 100% of some SMCs, was observed for the plant with the longest solid retention time. A fugacity-based model was established to simulate the transport and fate of SMCs in the WWTP, and good agreement was obtained between the measured and modeled values. These findings indicate that the levels of certain SMCs discharged into the atmospheric and aquatic environments were substantial, potentially resulting in exposure to both humans and wildlife.

Neuroprotective effects of exosomes derived from bone marrow mesenchymal stem cells treated by Musk Ketone on ischemic stroke

ObjectivesIschemic stroke (IS) is a leading cause of morbidity and mortality globally. This study aimed to investigate the role of exosomes (Exo) derived from bone marrow mesenchymal stem cells (BMSCs) treated with Musk Ketone (Mus treated-Exo) in the development of IS injury. MethodsBMSCs were pretreated with 10 μM Mus for 36 h, and Exo derived from these Mus-treated BMSCs (Mus-treated Exo) were extracted. Rats with middle cerebral artery occlusion (MCAO) were administered either 2 mg/kg of control Exo (Ctrl-Exo), 2 mg/kg of Mus treated-Exo, or 10 μM Mus. Neurological deficit and cerebral infarction in the MCAO rats were assessed utilizing neurological scores and TTC staining. Neuronal apoptosis, activation of microglia/macrophages, and inflammation were evaluated through TUNEL staining, immunofluorescence staining, and western blot analysis, respectively. ResultsOur findings revealed that Mus-treated Exo possessed a more pronounced neuroprotective effect on MCAO rats when compared to Ctrl-Exo and Mus treatment alone. Specifically, Mus treated-Exo effectively ameliorated neurological function, reduced the volume of cerebral infarction, and diminished hemispheric swelling in MCAO rats. Moreover, it inhibited neuronal apoptosis and activation of microglia/macrophages, promoted the expression of the anti-apoptotic protein Bcl-2 while decreasing the expression of pro-apoptotic protein Bax, Cleaved-caspase 3, and pro-inflammatory factors IL-6 and COX-2. ConclusionsThe findings imply that Mus treated-Exo could confer neuroprotection in rats affected by IS, potentially by attenuating apoptosis and neuroinflammation. The underlying mechanisms, however, warrant further investigation. Mus treated-Exo shows potential as a new therapeutic strategy for IS.

Photodegradation of the main synthetic musk (HHCB) in water: kinetic study and influencing factors.

Galaxolide (HHCB) is the most common synthetic musk compound detected in numerous daily products. Despite its persistence in the aquatic environment, the photodegradation of HHCB remains poorly understood. In this study, we investigated the direct and indirect photolysis kinetics of HHCB under simulated sunlight and UVC light. Our aim was to determine the role of reactive oxygen species (ROS) responsible for HHCB degradation in the aquatic environment and to identify its transformation products. The influence of environmental factors on indirect photolysis was investigated by testing both synthetic waters (containing humic acid, carbonate (CO32-), and nitrate (NO3-)) and real waters (riverine and effluent). Hydrogen peroxide (H2O2/UVC) was tested to simulate the wastewater treatment process. Quencher experiments were conducted to identify the role of ROS in HHCB photodegradation, including hydroxyl radicals (˙OH), carbonate radicals (CO3˙-), triplet states of dissolved organic matter (3DOM*), and singlet oxygen (1O2). The results clearly indicated that HHCB was efficiently degraded by direct photolysis under both light conditions. The presence of H2O2 led to the most efficient HHCB degradation due to the high production of ˙OH induced under UVC. Indirect photolysis contribution was observed, induced by ˙OH, CO3˙-, 3DOM*, and 1O2 to different extents depending on the light and matrix composition. The experiments led to the detection of transformation products: HHCB lactone, a well-known transformation product, and two other substances with proposed structures. This study provides a comprehensive identification of the processes involved in the direct and indirect photodegradation of HHCB, which could serve as the basis for evaluating and modeling the fate of HHCB in aquatic environments.

Musk ketone solubility in binary systems ethyl acetate with methanol, ethanol, and isopropanol: preferential solvation according to the inverse Kirkwood–Buff integrals method

ABSTRACT Three co-solvent mixtures {methanol (1) + ethyl acetate (2), ethanol (1) + ethyl acetate (2), and isopropanol (1) + ethyl acetate} were used to calculate the preferred solvation parameters () of musk ketone (MK) (2). In all co-solvent mixes, values vary non-linearly with the percentage of co-solvent (1). According to the study, values are negative in mixes rich in alcohol but positive in those high in ethyl acetate. The mixtures {methanol (1) + ethyl acetate (2)} and {ethanol (1) + ethyl acetate (2)} show the most favoured solvation of MK by ethyl acetate at 298.15 K and 293.15 K, respectively. When {isopropanol (1) + ethyl acetate (2)} is combined; it is maximum at 298.15 K. Since the values are positive, MK preferentially solvates with ethyl acetate. The most significant values for x 1 = 0.18–0.40 are obtained towards the non-polar regions of MK for the three co-solvent mixes.

Fabric phase sorptive extraction as a sustainable sample preparation procedure to determine synthetic musks in water

A rapid sample preparation fabric phase sorptive extraction (FPSE) methodology followed by gas chromatography coupled to tandem mass spectrometry is proposed for the first time to determine 12 synthetic musks including nitro-, polycyclic and macrocyclic musk in environmental water and wastewater. An asymmetric screening design of experiments was used to evaluate the influence of nine parameters affecting FPSE in only 16 experiments. The factors included the sol–gel sorbent coating, stirring mode (both extraction and desorption), extraction and desorption time, salting-out effect, sample volume, type of solvent, and desorption solvent volume. The selected conditions imply the use of the sol–gel PDMS sorbent coating, 15 min extraction by ultrasound energy employing 10 mL of sample and 0.5 mL of ethanol as desorption solvent during 5 min. Accuracy and precision were assessed in different real water samples. Matrix effects were evaluated performing recovery studies in several aqueous matrices: river, sea, spring, laundry washing place, and wastewater at different concentration levels (0.1, 2, 10 µg L−1) demonstrating method accuracy (results ranged between 82 and 110%) and good precision (relative standard deviation, RSD < 12% in all cases). Limits of detection (LODs) were below 8 ng L−1 for the analyzed synthetic musks. As extraction was quantitative (exhaustive extraction), calibration was carried out using solvent standards without the need of repeating the extraction step, which is required in most microextraction methods, improving sample throughput, and reducing costs. Finally, the analysis of real contaminated samples revealed the presence of 11 out of the 12 target synthetic musks at concentrations up to 30 µg L−1, three of them banned in cosmetic regulation (musk tibetene, ambrette, and moskene). The developed FPSE based methodology uses low volume (0.5 mL) of a Generally Recognized as Safe (GRAS) solvent (ethanol), as well as minimum energy and time consumption, demonstrating to be a sustainable alternative to detect these microcontaminants in environmental waters and wastewaters.

Allergens and Other Harmful Substances in Hydroalcoholic Gels: Compliance with Current Regulation.

Hydroalcoholic gels or hand sanitisers have become essential products to prevent and mitigate the transmission of COVID-19. Depending on their use, they can be classified as cosmetics (cleaning the skin) or biocides (with antimicrobial effects). The aim of this work was to determine sixty personal care products frequently found in cosmetic formulations, including fragrance allergens, synthetic musks, preservatives and plasticisers, in hydroalcoholic gels and evaluate their compliance with the current regulation. A simple and fast analytical methodology based on solid-phase microextraction followed by gas chromatography-tandem mass spectrometry (SPME-GC-MS/MS) was validated and applied to 67 real samples. Among the 60 target compounds, 47 of them were found in the analysed hand sanitisers, highlighting the high number of fragrance allergens (up to 23) at concentrations of up to 32,458 μg g-1. Most of the samples did not comply with the labelling requirements of the EU Regulation No 1223/2009, and some of them even contained compounds banned in cosmetic products such as plasticisers. Method sustainability was also evaluated using the metric tool AGREEPrep, demonstrating its greenness.

Occurrence, time trends, and human exposure of siloxanes and synthetic musk compounds in indoor dust from Korean homes

Siloxanes and synthetic musk compounds (SMCs) have been widely used as additives in household and personal care products. Humans are easily exposed to siloxanes and SMCs originating from these products through ingestion and dermal absorption of indoor dust. In the present study, indoor dust samples were analyzed for 19 siloxanes (cyclic and linear) and 12 SMCs (polycyclic, macrocyclic, and nitro musks) to assess their occurrence, time trends over time, source, and health risks. A total of 18 siloxanes and 10 SMCs were detected in all indoor dust samples obtained from 2011⎯2021, indicating widespread and long-term contamination. Higher detection frequencies and concentrations were associated with siloxanes and SMCs with higher use and strong resistance against degradation processes. Indoor dust samples were dominated by linear siloxanes (L11–L13), 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyran (HHCB), musk ketone (MK), and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN). The frequent use of household and personal care products is likely an important source of siloxane and SMC contamination in indoor environments. The concentrations of siloxanes and SMCs in indoor dust increased from 2011 to 2021, particularly, those of linear siloxanes, reflecting the impact of regulatory actions addressing cyclic siloxanes. The profiles of siloxanes remained stable throughout the study period, whereas those of SMCs shifted from nitro to polycyclic musks. The estimated daily intakes (EDIs) of siloxanes and SMCs arising from ingestion were greater than from dermal absorption of indoor dust. The EDIs of siloxanes and SMCs associated with indoor dust indicated that children are exposed to these pollutants.

Mitigating abortion risk of synthetic musk-contained body wash in pregnant women: Risk assessment and mechanism analysis

Synthetic musks (SMs), the widely used odor component in personal care products have attracted attention due to their environmental impacts, especially the abortion risks. Given that women comprise a significant consumer demographic for personal care products, it is imperative to promptly initiate research on avoidance strategies for pregnant women concerning their exposure to synthetic chemicals (SMs). This study tried to establish novel theoretical approaches to eliminate the abortion risks of SM-contained body wash by designing the SM-contained proportioning scheme and analyzing the abortion risk mechanisms. The binding energy of SMs to estrogen-progesterone protein complex was used as an indicator of the abortion risk. A total of 324 SM-contained body wash proportioning schemes were designed using full factorial design and No. 218 was found as the most effective formula for body wash proportioning with the binding energy value of 68.6 kJ/mol. Results showed the abortion risk could be effectively alleviated (reduced 0.6%–163.4%) by regulating the proportioning scheme of SM-contained body wash. In addition, the mechanism analysis of SM-contained proportioning scheme proportioning scheme found that xanthan gum and disodium EDTA played essential roles in reducing the abortion risk in pregnant women after exposure. The selection of proper body wash components for reducing the abortion risk of SMs on pregnant women was first proposed. It sheds lights on the potential risks of people's daily life and proposes risk-eliminating strategies.

Behaviour of synthetic musk fragrances in freshwaters: occurrence, relations with environmental parameters, and preliminary risk assessment

The aims of this study were to investigate the presence, possible sources, and potential ecological risks of synthetic musk fragrances in freshwaters and sediments of the main tributaries of a deep subalpine lake in Northern Italy. The total musk concentrations ranged from few ng L−1 up to values > 500 ng L−1, depending on river characteristics: water flow and the presence of wastewater effluents proved to be the main factors affecting fragrance concentrations. The water flow may indeed dilute fragrance input mainly deriving from treated wastewaters. Good correlations (determination coefficients > 0.60) between synthetic fragrances concentrations and parameters related to anthropogenic impacts confirmed this hypothesis: synthetic fragrances were mainly detected in most polluted rivers crossing urbanized areas. Sediment analysis highlighted accumulation of fragrances in this matrix. Concentrations of synthetic fragrances up to 329 ng g−1 organic carbon were measured in sediments of the most contaminated rivers Boesio and Bardello, which also show the highest nutrient content. The preliminary environmental risk assessment revealed that present levels of synthetic musk fragrances do not pose any risk to the studied environmental compartments. However, a probable medium risk level was evidenced during the dry season in the most contaminated rivers Boesio and Bardello. For these reasons, small rivers draining urbanized watersheds and affected by wastewater effluents should be considered synthetic musk contamination hotspots that warrant further research.

A multi-residue method for the analysis of organic pollutants released from atmospheric PM2.5 in simulated biological fluids: Inhalation bioaccessibility and bioavailability estimation

BackgroundIn recent decades, there has been a growing interest within the scientific community regarding the study of the fraction that could be released in simulated biological fluids to estimate in vitro bioaccessibility and bioavailability of compounds. Concerning particulate matter (PM), studies were essentially focused on metal (oid)s probably due to more complex methodologies needed for organic compounds, requiring extraction and pre-concentration steps from simulated fluids, followed by chromatographic analysis. Thus, the development of a simple and sensitive methodology for the analysis of multi-class organic compounds released in different inhalation simulated fluids would represent a great contribution to the field. ResultsIn this work, a methodology for the analysis of 49 organic pollutants, including 18 polycyclic aromatic hydrocarbons (PAHs), 12 phthalate esters (PAEs), 11 organophosphorus flame retardants (OPFRs), 6 synthetic musk compounds (SMCs) and 2 bisphenols released in simulated fluids from PM2.5 samples was developed. After a physiologically based extraction test (PBET) by using artificial lysosomal fluid (ALF) and a simulated body fluid (SBF, filling a dialysis membrane) to obtain in vitro inhalation bioaccessible and bioavailable fractions, respectively; compounds were determined by a vortex-assisted liquid-liquid extraction (VALLE) and a subsequent analysis by programmed temperature vaporization-gas chromatography-tandem mass spectrometry (PTV–GC–MS/MS). Experimental conditions concerning VALLE extraction (extraction time and amount of NaCl (g)) were optimized by using a central composite design (CCD), best MS/MS transitions were selected and matrix-matched calibration combined with use of labelled subrogate standards provided high sensitivity, minimization of matrix effects and recovering losses compensation. SignificanceThe successful validation results obtained for most of the compounds demonstrated the effectiveness of the proposed methodology for the analysis of multi-class organic pollutants released in ALF and SBF for inhalation bioaccessibility and bioavailability assessment, respectively. Furthermore, applicability of the method was proved by analysing 20 p.m.2.5 samples, being the proposed in vitro PBET dialyzability approach for assessing organic pollutant's inhalation bioavailability applied to PM2.5 samples for the first time.

Floating plastics as integrative samplers of organic contaminants of legacy and emerging concern from Western Mediterranean coastal areas

This study investigates the role of floating plastics as integrative samplers of organic contaminants. To this end, plastics items were collected in two Western Mediterranean coastal areas: the Mar Menor lagoon, and the last transect of Ebro river. Floating plastics were identified and characterized by attenuated total reflection Fourier-transform infrared spectrometry. Then, organic contaminants were extracted from plastic items by ultrasonic extraction with methanol, and the concentrations of 168 regulated and emerging contaminants were analysed. These compounds were analysed by stir bar sorptive extraction coupled to gas chromatography–mass spectrometry (GC–MS), except for bisphenol analogues, which were analysed with a ultraperformance liquid chromatography pump coupled to a triple quadrupole mass spectrometer (UHPLC-MS/MS), and pharmaceutical compounds, determined by UPLC coupled to hybrid triple quadrupole-linear ion trap mass spectrometer (UPLC-MS/MS). All the contaminants groups considered were detected in the samples, being particularly relevant the contribution of plastic additives. The most frequently detected contaminants were UV-filters, PAHs, pharmaceuticals and synthetic musks. Apart from plasticizers, the individual contaminants octocrylene, homosalate, galaxolide, salycilic acid and ketoprofen were frequently detected in plastics items. The results pointed out to urban and touristic activities as the main sources of pollution in the coastal areas investigated. The utility of floating plastics as integrative samplers for the detection of organic contaminants in aquatic ecosystems has been demonstrated.

Multi-class organic pollutants in PM2.5 in mixed area of Shanghai: Levels, sources and health risk assessment

The occurrence of 25 multi-class pollutants comprising phthalate esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), and synthetic musks (SMs) were studied in PM2.5 samples collected at an industrial/commercial/residential/traffic mixed area in Shanghai during four seasons. During the whole period, a slight exceedance of the PM2.5 annual limit was observed, with an average of 36.8 μg/m3, and PAEs were the most predominant, accounting for >70 % of the studied organic pollutants in PM2.5, followed by PAHs and SMs. Statistically significant differences were observed for the concentrations of PM2.5, PAEs, PAHs, and SMs in winter and summer. This seasonal variation could be derived from anthropogenic activities and atmospheric dynamics. Principal component analysis (PCA) and PAHs ratios suggested a mixed source mainly derived from vehicle emissions and industrial processes. Moreover, gaseous pollutants were also accounted for, indicating the emission of PAHs might accompany the NO2 emission process. Finally, inhalation of PM2.5-bound organic pollutants for carcinogenic and non-carcinogenic risks were estimated as average values for each season, showing outside the safe levels in autumn and winter in some cases, suggesting that new policies should be to developed to reduce their emissions and protect human health in this area.

Hydrophobic organic contaminants affiliated with polymer-specific microplastics in urban river tributaries and estuaries

Exposure to microplastics (MPs) and hydrophobic organic contaminants (HOCs) combined at high concentrations may induce adverse effects to aquatic organisms in laboratory-scale studies. To determine environmentally relevant concentrations of HOCs in MPs, it is essential to understand the occurrence of MP-affiliated HOCs in the aquatic environment. Here we report the occurrences of HOCs affiliated with polymer-specific floating MPs from 12 tributaries and three estuaries in the Pearl River Delta, South China. Target HOCs include nine synthetic musks (SMs), 14 ultraviolet adsorbents (UVAs), 15 polycyclic aromatic hydrocarbons (PAHs), eight polybrominated diphenyl ethers (PBDEs), and 14 polychlorinated biphenyls (PCBs). Average concentrations of MP-affiliated ∑9SM, ∑14UVA, ∑15PAH, ∑8PBDE, and ∑14PCB were 1790, 5550, 1090, 412, and 107 ng g−1, respectively. The average concentrations of HOCs affiliated with MPs of different polymer types were 9790, 7220, 72,500, and 55,800 ng g−1 for polyethylene (PE), polypropylene, polystyrene, and other MPs, respectively. As the concentration of PE was the highest among all MPs at the average concentration of 0.77 mg m−3, the monthly outflow of PE-affiliated HOCs accounted for the largest proportion (46 %) in the outflow of MP-affiliated HOCs (2.8 g) to the coastal ocean via three estuaries. These results suggest that HOCs were highly concentrated in MPs and varied among different chemicals and polymer types. Due to the differences of polymer characteristics and half-life of affiliated chemicals, future toxicology studies concerning exposure to these combined pollutants may need to specify polymer types and their affiliated chemicals.

Chemical Constitutions of Natural Musk and Research Progress of Synthetic Musk

Natural musk, which is released by adult male musk deer, has vital use in medicine, cosmetics, detergents, and other fields. This paper has mentioned that as a result of its predominant composition of macrocyclic ketones, pyridine, alcohols, fatty acids, polypeptides (PEP-tides), proteins, and other desired but uncommon substances, synthetic musk was created. The synthetic musk has been divided into four groups based on its chemical composition: nitrogen-containing musks (NMs), polycyclic musks (PMs), macrocyclic musks (MMs), and alicyclic musk or linear musk (AMs). The history of the creation of compounds with musk odor, the development of four different types of synthetic musk, and the negative impact of NMs, MMs, and PMs had all been mentioned in this article. Also, the creation and use of these different musks have all been discussed in this work. Synthetic musk still struggles with the cost of production and is unable to synthesize all of the components from genuine musk. Thus, there is still a lot of potential for the development of synthetic musk.