On-line coupling of solid-phase extraction to gas chromatography–mass spectrometry to determine musk fragrances in wastewater

For the occurrence of PPCPs from source to tap: A novel approach modified in terms of sample preservation and SPE cartridge to monitor PPCPs in our water supply

BACKGROUND

The ongoing infusion of pharmaceutical and personal care products (PPCPs) into ecosystems sustains a perpetual life cycle and leads to multi-generational exposures. Limited understanding of their environmental impact and their intrinsic ability to induce physiological effect in humans, even at low doses, pose great risks to human health. Few scholarly works have conducted systematic research into the occurrence of PPCPs within potable water systems. Concurrently, the associated monitoring techniques have not been comprehensively examined with regards to the specific nature of drinking water, namely whether the significant presence of disinfectants may influence the detection of PPCPs.

RESULTS

A modified approach in terms of detailed investigation of sample preservation and optimization of an in-lab fabricated solid phase extraction (SPE) cartridge filled with DVB-VP and PS-DVB sorbent was proposed. Favorable methodological parameters were achieved, with correlation coefficients spanning from 0.9866 to 0.9998. The LODs of the PPCPs fluctuated from 0.001 to 2 μg L-1, while the LOQs varied from 0.002 to 5 μg L-1. The analysis of spiked samples disclosed a methodological precision of 2.31-9.86 % and a recovery of 52.4-119 %. We utilized the established method for analyzing 14 water samples of three categories (source water, finished water and tap water) from five centralized water supply plants. A total of 24 categories encompassing 72 PPCPs were detected, with the concentrations of PPCPs manifested a marked decrease from source water to finished water and finally to tap water.

SIGNIFICANCE

Our research meticulously examined the enhancement and purification effects of widely used commercial SPE cartridges and suggested the use of in-lab fabricated SPE cartridges packed with DVB-VP and PS-DVB adsorbents. We also conducted a systematic evaluation of the need to incorporate ascorbic acid and sodium thiosulfate as preservatives for PPCP measurement, in consideration of the unique characteristics of drinking water matrices, specifically, the significant concentration levels of disinfectants. Furthermore, the proposed method was effectively employed to study the presence of PPCPs in source water, finished water, and tap water collected from centralized water supply plants.

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.

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.

Headspace solid-phase microextraction based on the metal-organic framework CIM-80(Al) coating to determine volatile methylsiloxanes and musk fragrances in water samples using gas chromatography and mass spectrometry

A headspace solid-phase microextraction (HS-SPME) method was developed using the metal-organic framework (MOF) CIM-80(Al) as extraction phase and in combination with gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 6 methylsiloxanes and 7 musk fragrances in different environmental waters. The chromatographic separation was optimized in different GC instruments equipped with different detectors, allowing the correct separation and identification of the compounds. The HS-SPME method was optimized using a Box-Behnken experimental design, while the validation was carried out together with the most suitable commercial fiber (divinylbenzene/polydimethylsiloxane) for comparison purposes. The MOF-based coating was particularly efficient for the determination of volatile methylsiloxanes, showing moderately lower limits of detection (of 0.2 and 0.5 μg L^-1versus 0.6 μg L^-1 for cyclic methylsiloxanes) and slightly better precision (relative standard deviation values lower than 17% versus 22%) than the commercial coating, while avoiding the cross-contamination issues associated to the polymeric composition of commercial fibers. The method was applied for the analysis of seawater and wastewater samples, allowing the quantification of several analytes and the assessment of matrix effects. The proposed HS-SPME method using the CIM-80(Al) fiber constitutes a more environmentally friendly, simpler, and efficient strategy in comparison with other sample preparation methods using different extraction techniques, while the use of a MOF as fiber sorbent constitutes a potential alternative to exploit the features of SPME for the challenging environmental monitoring of these compounds.

Effects of the Fragrance Galaxolide on the Biomarker Responses of the Clam Ruditapes philippinarum

The musk fragrance Galaxolide® (HHCB) is widely used in personal care and household products. Its large use leads to a continuous release of the compound into aquatic environments. Although some studies on the presence of HHCB in ecosystems and biota have been conducted, limited data about its effects on organism biomarkers are available. This study aimed at investigating both cellular and biochemical effects of HHCB in the clam Ruditapes philippinarum. Mussels were exposed for 7, 14 and 21 days to 100 ng/L and 500 ng/L of HHCB in seawater, and the effects on haemocyte parameters and antioxidant enzyme activities in the gills and digestive gland were evaluated. In addition, the neurotoxic potential of HHCB and its capacity to cause oxidative damage to proteins were assessed. Overall, our results demonstrated that exposure to HHCB was able to induce changes in biomarker responses of mussels, mainly at the cellular level.

Occurrence and Sources of Synthetic Musk Fragrances in the Sewage Treatment Plants and the Han River, Korea

Levels of synthetic musk fragrances (SMFs) and various personal care products (PCPs) were measured in the Han River and its tributaries in Seoul, Korea. The most abundant SMF in all river and PCP samples was 4,6,6,7,8,8-hexamethyl-1,3,4,7-tetrahydrocyclopenta(g)sochromene (HHCB), followed by 1-(3,5,5,6,8,8-hexamethyl-6,7-dihydronaphthalen-2-yl)ethanone (AHTN), musk ketone (MK), and 1,1,2,3,3-pentamethyl-2,5,6,7-tetrahydroinden-4-one (DPMI). The most abundant SMF in both PCPs and the Han River samples was HHCB, followed by AHTN. Moving from upstream to downstream in the Han River, the median SMF concentration was 6.756, 2.945, 0.304, and 0.141 μg/L in the sewage treatment plant (STP) influents, effluents, tributaries, and mainstream, respectively, implying that effective SMF removal was achieved during the sewage treatment process, followed by dilution in the receiving water. Four STPs using advanced biological treatment processes had removal efficiencies of 58.5%, 56.8%, and 38.1% for HHCB, AHTN, and MK, respectively. The highest SMF concentrations in the tributaries were observed at locations close to the STPs. Our study confirmed that the main source of SMFs in the receiving water were sewage effluents containing untreated SMFs, which largely originate from household PCPs, especially hair care products (e.g., shampoo) and perfumes.

In situ measurement of synthetic musks in wastewaters using diffusive gradients in thin film technique

Synthetic musks (SMs) are used extensively in household and personal care products and have acted significant concerns due to their environmental impacts and potential health effects. Here, we present a passive sampling approach based on diffusive gradients in thin films (DGT) for in situ measurement of SMs in urban wastewaters. XAD-2 binding gel, which has a rapid binding rate and high elution efficiency, was used in DGT device for the accumulation of six polycyclic musks and three nitro musks. The diffusion coefficients (D and D_NL) of the SMs through agarose gel without and with a nylon filter membrane were 3.37-4.49 and 1.48-4.41 ×10^-6cm² s^-1. The filter membrane caused an ~3 h lag phase and slowed the diffusion rates of the SMs through the diffusive phase. Solution pH (4.30-8.92), ionic strength (0.0001-0.5 M) and dissolved organic matter (0-20 mg L^-1) showed no obvious influence on uptake of the SMs in DGT. The measured average SM concentrations in the effluent of wastewater treatment plants ranged from 0.45-696 ng/L for DGT deployment, without obvious membrane biofouling, and they were comparable to the concentrations determined by grab sampling. These results confirmed that the present method is reliable and convenient for in situ measurement of semivolatile hydrophobic SMs in complicated waters and is an available tool to investigate the environmental behaviors of SMs in the environment.

An Insight into Ingredients of Toxicological Interest in Personal Care Products and A Small–Scale Sampling Survey of the Greek Market: Delineating a Potential Contamination Source for Water Resources

Wastewater is not a waste but a valuable resource that should be reused. Nevertheless, it should be devoid of physical, chemical, and microbiological parameters that can harm the consumer. Along with the multitude of possible pollutants found in wastewater treatment plants (WWTPs), emerging pollutants, such as Personal Care Products (PCPs), have arisen. The present research examines some of the main ingredients commonly found in PCPs, focusing on their toxicological profile on their occurrence in WWTPs influents and effluents worldwide and on their persistence and biodegradability. A small-scale market sampling of PCPs was performed in Athens, Greece, in June 2019, and their individual ingredients were recorded, coded according to their main activity, scanned for the presence of ingredients of important toxicological profile, and finally analyzed for the presence of other candidates of toxicological interest. Results show that some ingredients of concern (i.e., parabens and triclosan) are a decreasing trend. On the other hand, information on the presence of synthetic musks and perfume synthesis is scarce and encumbered by brand protection. Finally, UV filters are numerous, and they are used in various combinations, while other ingredients of toxicological interest are also present. Since the reclaimed water may well be used to cover irrigation needs in Greek areas with water deficiency or to enrich bodies of surface water, it is important to know what PCP ingredients are on the rise in the market, to monitor their presence in WWTPs influents and effluents and to extend research on their environmental fate and behavior.

Effect of polycyclic musk compounds on aquatic organisms: A critical literature review supplemented by own data

Synthetic musk compounds are extensively used in personal care and cosmetic products around the world. Because they are not completely removed in sewage treatment plants, they eventually end up in aquatic environments. The aim of this review was to summarize published information on effects of polycyclic musks on aquatic organisms and to discuss whether the experimental design of toxicological studies involving these substances could influence the results obtained. With the exception of one study run in a flow-through system, all published toxicological studies on synthetic polycyclic musks have been conducted in semi-static or even static systems. Based upon data in the literature and our own results, we conclude that in toxicological tests with semi-static set-ups, concentrations of polycyclic musks decrease with time between bath exchanges, and, as a result, tested organisms are not being exposed to stable concentrations but rather to concentration pulses. The duration and character of these pulses are influenced mainly by aeration of experimental baths, as polycyclic musks have a tendency to volatilize from water baths. Under semi-static conditions, tested organisms may be subjected to lower concentration of the tested substance for relatively long periods. Those levels may even fall below the limits of quantification. During these periods, some level of detoxification and/or elimination (depuration) of the toxicant may reduce toxic effect of the previous exposures. Consequently, toxicity of polycyclic musk substances for aquatic organisms obtained under these conditions may be underestimated. Based upon existing data in the literature, therefore, it is very difficult to correctly estimate risk of polycyclic musks to aquatic organisms.

Synthetic Musks: A Class of Commercial Fragrance Additives in Personal Care Products (PCPs) Causing Concern as Emerging Contaminants

Synthetic musks (SMs) are promising fragrance additives used in personal care products (PCPs). The widespread presence of SMs in environmental media remains a serious risk because of their harmful effects. Recently, the environmental hazards of SMs have been widely reported in various environmental samples including those from coastal and marine regions. This paper provides a systematic review of SMs, including their classification, synthetic routes, analysis and occurrence in environmental samples, fate and toxicity in the environment, as well as the associated risk assessment and pollution control. Research gaps and future opportunities were also identified with the hope of raising interest in this topic.

Simulating latrine conditions to assess perfume performance against malodour

To evaluate perfume performance in toilets, we built model toilets in which critical factors such as background malodour, climate, and airflow were controlled. The models were equipped with an odour generator that injected hydrogen sulfide, methyl mercaptan, butyric acid, para-cresol, and indole, allowing us to accurately and reliably reconstitute toilet malodour headspace. The malodorant concentrations matched the quantitative headspace analysis performed in African and Indian toilets. The toilet malodour headspace performance was validated by chemical and sensory analysis. Olfactory stimuli were presented to participants in different simulated climates to assess the effect of climate on the perception of odours. The sensory data show that increasing temperature and humidity decreased the intensity ratings of odours without altering their quality. Perfume can be delivered in these toilets by forced evaporation to control the headspace concentration, or by delivery systems such as cellulosic pads, liquids, and powders. Our experimental set-up allowed us to establish dose-response curves to assess the performance of a perfume in reducing toilet malodour and increasing perceived pleasantness.

Occurrence of personal care products as emerging chemicals of concern in water resources: A review

Personal care products (PCPs) are a diverse group of common household substances used for health, beauty and cleaning purposes. These include disinfectants, fragrances, insect repellents, preservatives and UV filters, among others. Some of them are considered chemicals of emerging concern due to their presence and negative impact on aquatic ecosystems, specially related to endocrine disruption and reproductive disorders. The entry of those chemicals to water bodies occurs mainly through the sewage effluents from wastewater treatment plants due to their incomplete or inefficient removal. The purpose of this review was to collect and analyze data about the incidence and concentrations of PCPs reported as emerging pollutants in different water matrices, including wastewater influents and effluents. Our database is composed of 141 articles with information about 72 PCPs recorded as emerging pollutants in 30 countries, in concentrations ranging from 0.029ng/L to 7.811×10⁶ng/L. Fragrances, antiseptics and sunscreens were the most reported groups. As expected, the largest number of PCPs documented as emerging pollutants were found in wastewater treatment plant effluents with a total of 64 compounds, compared to 43 in surface water and 23 in groundwater, which evidence the anthropological contribution of PCPs to water bodies. These molecules were found in all the continents, however, there is a lack of information regarding the presence of emerging pollutants from PCPs in developing countries. Therefore, we suggest further efforts in assessing the occurrence and concentrations of these chemicals in those areas.

Degradation of synthetic fragrances by laccase-mediated system

Laccase mediator systems are important biodegradation agents as the rate of reaction could be enhanced in the presence of redox mediators. In the present study the commercial enzyme laccase from Trametes versicolor and the redox mediator 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) were used for the biotransformation of the synthetic fragrances 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8,-tetramethyl-2-naphthyl)ethan-1-one (Iso-E-Super, OTNE), 1,3,4,6,7,8,-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[g]-2-benzopyran (Galaxolide, HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphtalene (Tonalide, AHTN) and the transformation product of HHCB, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[g]-2-benzopyran-1-one (Galaxolidone, HHCB-lactone) in water. A particular focus was to assess the effects of the enzyme laccase from Trametes versicolor in the enantioselective degradation of the target compounds, for this reason gas chromatography with an enantioselective column was used as separation technique followed by mass spectrometry detection. In addition, as enantioselective degradation of musk fragrances was observed in wastewater, sewage sludge and fish samples, enantiomeric fractions of selected compounds were studied during composting. In a period of 144h, the target fragrances could be effectively removed by the enzyme laccase with removal percentages greater than 70%, except AHTN with a removal percentage of 42%. However, the degradation process prompted by the enzyme laccase was shown to be non-enantioselective as no significant differences were observer between the enantiomeric fractions calculated at the beginning and at the end of the degradation process. Meanwhile, the composting process was shown to be enantioselective.

Long lasting perfume--a review of synthetic musks in WWTPs

Synthetic musks have been used for a long time in personal care and household products. In recent years, this continuous input has increased considerably, to the point that they were recognized as emerging pollutants by the scientific community, due to their persistence in the environment, and hazardous potential to ecosystems even at low concentrations. The number of studies in literature describing their worldwide presence in several environmental matrices is growing, and many of them indicate that the techniques employed for their safe removal tend to be ineffective. This is the case of conventional activated sludge treatment plants (WWTPs), where considerable loads of synthetic musks enter mainly through domestic sewage. This review paper compiles and discusses the occurrence of these compounds in the sewage, effluents and sludge, main concentration levels and phase distributions, as well as the efficiency of the different methodologies of removal applied in these treatment facilities. To the present day, it has been demonstrated that WWTPs lack the ability to remove musks completely. This shows a clear need to develop new effective and cost-efficient remediation approaches and foresees potential for further improvements in this field.