Distribution and elimination of polycyclic musks in three sewage treatment plants of Beijing, China

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.

Roles of extracellular polymeric substances in the adsorption and removal of norfloxacin during hydrothermal treatment of sewage sludge

Hydrothermal treatment (HT) is promising to remove antimicrobials from sewage sludge (SS); however, the mechanism of antimicrobial degradation during the HT of SS is not fully understood. In this study, the roles of extracellular polymeric substances (EPS) in the removal and transformation of norfloxacin (NOR) during the HT of SS at temperatures of 100 and 160 °C were investigated. The results indicated that the degradation of NOR increased with increasing HT temperature, with maximum NOR removal (52%) achieved at 160 °C. Furthermore, the NOR in sludge showed higher degradation efficiencies than the control as HT temperature was higher than 120 °C. Evident promotion effects of bound-EPS (B-EPS) in sludge were observed on the NOR degradation as HT temperature was higher than 120 °C, leading to the mineralization and deamination of protein-like components in EPS during HT. Beside, the adsorption capacity of NOR during the HT of SS decreased at temperatures higher than 120 °C. The evolution of the spatial structure of B-EPS was predominantly responsible for the adsorption of antimicrobials, a spontaneous process driven mainly by hydrophilic interactions. With the hydrothermal conversion of B-EPS, the electron transfer, and reactive species (3EPS* and ·OH) derived from B-EPS could facilitate the degradation of NOR. In particular, hydrogen bonds between B-EPS and NOR increased the apparent yield of ·OH and accelerated the decarboxylation of NOR during HT at temperatures higher than 120 °C. A toxicity evaluation suggested that HT for NOR degradation could attenuate toxicity, whereas deep oxidation or mineralization would be needed to promote ecosystem safety. These findings provide new insights into the hydrothermal activation of EPS and the interrelated hydrothermal fate of antimicrobials and other toxic pollutants in sludge.

Screening of antimicrobials, fragrances, UV stabilizers, plasticizers and preservatives in sewage treatment plants (STPs) and their risk assessment in India

Community/industrial wastewater is the prime source of anthropogenic chemicals, its treatment is often a daunting task and unaffordable for many countries. Emerging Contaminants (ECs) have been drained into wastewater after continuous use/misuse and Conventional treatments in STPs do not remove them completely. ECs including antimicrobial agents, synthetic musks, Benzotriazole UV stabilizers (BUVSs), plasticizers, and preservatives are frequently reported in environment, and cause health effects to non-target organisms. Monitoring of ECs is important to understand their status in aquatic environment. Hence, it was aimed to monitor ECs (n = 21) from 11 STPs in Tamil Nadu, India. The detection frequency of most of these analytes was >90%. Antimicrobials ranged from 247 to 22,714 ng/L and 11-14,369 ng/L in influents and effluents, respectively. The synthetic musks were in the order of Tonalide > Galaxolide > Musk Ketone. BUVSs ranged from 4 to 1632 ng/L (influents) and < LOD to 29,853 ng/L (effluents). Concentration of phthalates in influents and effluents were < LOD - 11,311 ng/L and < LOD - 17,618 ng/L, respectively. Parabens were found in the order of Prophyl > Methyl > Ethyl > Butyl in influents and Methyl > Prophyl > Butyl > Ethyl in effluents. Mass loads of ECs through STPs were found as antimicrobials > plasticizers > fragrances > BUVSs > Preservatives. This study reveals increasing usage of ECs and inadequate treatment processes at STPs in India. Also helps to adopt suitable treatment processes to remove ECs from wastewater and to reuse the wastewater.

Tonalide facilitates methane production from anaerobic digestion of waste activated sludge

Tonalide (AHTN), a typical polycyclic musk and an emerging pollutant, was found to be enriched in waste activated sludge (WAS). However, the research of its effect on WAS anaerobic digestion was seldom available. This research therefore investigated the effect of AHTN on WAS anaerobic digestion and the underlying mechanism through batch experiments using either real WAS or synthetic wastewaters as the digestion substrates. The results indicated that when the concentration of AHTN increased from 0 to 1000 mg/kg TSS in WAS, the methane production increased linearly from 125.0 ± 2.2 to 162.9 ± 1.6 mL/g VSS, while the AHTN concentration further increased to 2000 mg/kg TSS, the methane production decreased to 146.2 ± 2.1 mL/g VSS. At the same time AHTN can facilitate the utility of volatile fatty acid (VFAs), especially acetate and propionate. It was further found that the degradation efficiency of AHTN in anaerobic digestion was 42.7%. The mechanism investigation demonstrated that AHTN can promote the solubilization, homoacetogenesis, acetogenesis and methanogenesis processes, leading to an increase in methane production. Further analysis revealed that methanogenic archaea mainly belonged to the genera of Methanosaeta and Metheanobacterium, and their relative abundance increased accordingly with the addition of AHTN.

Emerging contaminants in aquatic environments and coastal waters affected by urban wastewater discharge in Thailand: An ecological risk perspective

Emerging contaminants such as synthetic musks and UV-filters as ingredients personal care products were widely used in human daily life in Thailand. The occurrence and fate of four synthetic musks and nine UV-filters were investigated in eight full-scale sewage treatment plants (STPs) and their receiving aquatic environments in Bangkok and Pattaya, Thailand. All target compounds were detected in every single sample from STPs and surface water with magnitude from ng/L to μg/L. HHCB-lactone and HMS were found as the predominant musk and UV filter in influent and effluent of STPs, respectively. HHCB-lactone was also found with the highest concentration up to 79501 ng/g (dw) in the sludge. Low removal efficiency range from -37% (HHCB-lactone) to 58% (AHTN) were found for four musks in the STPs. The total emission of Σ₄musks and Σ₉UV-filters were estimated to be up to 16.7 mg/person/day and 0.28 mg/person/day by the STPs. Three synthetic musks and seven UV-filters were detected in fish from the receiving river. Concentration and emission of musks and UV filters found in this study from Thailand were much higher than those reported in many other countries worldwide. The preliminary ecological risk assessment showed that Musk xylene, 4-MBC and OC may pose high risk to aquatic organisms in the riverine and estuarine environment in Thailand.

Polycyclic musk fragrances (PMFs) in wastewater and activated sludge: analytical protocol and application to a real case study

Two different analytical methods for the determination of polycyclic musk fragrances (PMFs) in wastewater and in activated sludge were developed. PMFs in filtered water samples were determined by gas chromatography coupled with a triple-quadrupole mass spectrometer in selected reaction monitoring (SRM) mode. Activated sludge samples were extracted using an ultrasonic bath and analysed using a GC-Ion trap. The developed methods respected a linear model (R2 > 0.995). Detection limits of selected compounds (Celestolide, Galaxolide, Galaxolidone, Phantolide and Tonalide) varied from 1.7 to 80 ng L-1 for water and from 0.1 ng g-1 to 210 ng g-1 for activated sludge considering laboratory contamination for each PMF. Recovery studies were performed on spiked water samples and, for sludges, on procedural blanks, showing recoveries above 70% for all the considered compounds, while recovery of the internal standard was always above limit of acceptance (30%). Proposed methods were used to determine PMFs concentrations in wastewaters and activated sludges of a wastewater treatment plant (WWTP) located in Northern Italy. Concentrations in the range of μg L-1 of Galaxolide and of its metabolite Galaxolidone were detected even in the WWTP effluent. Biotransformation of Galaxolide into Galaxolidone occurred during biological treatment with the consequent release of this compound through WWTP effluents. In activated sludges, concentrations of all PMFs except Galaxolidone were one order of magnitude higher than wastewaters, as expected according to their physicochemical properties. Present wastewater treatment technologies were confirmed to not be efficient in removing PMFs from influent wastewaters since with only ≃ 30% of Celestolide and Tonalide were removed.

Polycyclic musks in surface water and sediments from an urban catchment in the megacity Beijing, China

Two typical polycyclic musks (PCMs), namely 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), were determined in 63 surface water and 42 sediment samples collected from the North Canal River watershed, an urban catchment located in the megacity Beijing, China. Concentrations of HHCB and AHTN were 13.2 ng/L-395 ng/L and 2.98 ng/L-232 ng/L in surface water, while 4.10 ng/g-818 ng/g and 1.21 ng/g-731 ng/g in sediments. The results showed that PCM concentrations in the North Canal River watershed were at the high end when compared to that in other regions in China and worldwide. A watershed-wide annual mass budget showed that HHCB (∼150 kg/year) and AHTN (∼80 kg/year) mainly originated from urban wastewaters. Both PCMs were eliminated primarily by outflowing water (72 kg/year and 43 kg/year for HHCB and AHTN, respectively) and due to losses to the atmosphere (40 kg/year and 26 kg/year for HHCB and AHTN, respectively). An assessment of ecological risks posed by HHCB and AHTN to aquatic organisms in the North Canal River watershed was performed by using a tiered ecological risk assessment. The results showed that PCMs were unlikely to pose an ecological risk at the watershed scale (the probability of the incidence of adverse effect was <3.5% at the 99% protection level). However, according to the results from the risk quotient method, the tributaries draining wastewater effluents should be hotspots that warrant further research in future.

Development of environmental risk assessment framework and methodology for consumer product chemicals in China

Environmental risk assessment (ERA) methodologies for consumer product chemicals are well established in most developed regions including the United States, Canada, and the European Union. However, such methodologies are not yet fully developed for emerging economies, such as China. The objective of the present study was to develop an ERA framework involving an exposure methodology using conditions specific to China (i.e., physical setting, infrastructure, and consumers' habits and practice). Incorporated in this newly developed ERA framework for assessing consumer product chemicals were China's current regulatory screening and prioritization schemes as part of a tiered risk assessment approach. The framework started with tier 0, which utilized the existing Chinese regulatory qualitative method; tiers 1 and 2 were quantitative, and used deterministic and probabilistic methods that accounted for per capita residential water usage, wastewater treatment capability, and wastewater/in-stream dilution factors. Due to major differences in wastewater treatment infrastructure and water usage between urban versus rural regions in China, 2 scenarios were identified for quantitatively assessing environmental exposure: 1) urban with wastewater treatment, and 2) rural without wastewater treatment (i.e., direct discharge of wastewater). Our study presents the methodology of the framework with its technical rationale and the companion model Chera, and also provides an overview of the current status of ERA research in China. Environ Toxicol Chem 2019;38:250-261. © 2018 SETAC.

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.

Elimination of typical polycyclic musks in a full-scale membrane bioreactor combined with anaerobic-anoxic-oxic process in municipal wastewater treatment plant

The objective of this study was to investigate the removal of 11 synthetic polycyclic musks in a municipal wastewater treatment plant located in Jilin, China, by using a membrane bioreactor combined with anaerobic-anoxic-oxic process. The analysis of synthetic polycyclic musks was conducted with gas chromatography/mass spectrometry after solid-phase extraction. The removal efficiency of 11 synthetic polycyclic musks ranged from 65.9% (3-methylcyclopentadecanone) to 84.6% (Galoxolide) in the influent. Along the treatment process, it was observed that the anaerobic tank could remove the synthetic polycyclic musks effectively whereas the role of the membrane was to the musks, which could be ascribed to the relatively strong hydrophobic property of the musks. The sludge-water distribution coefficients (K_d values) as indicator of adsorption propensity for the sludge from anaerobic, anoxic, oxic and membrane tanks were measured. The high value of K_d, above 5.0 litres per gram of suspended solids, showed most of the musks could be removed by sludge through the adsorption process; thus the removal rate from the water phase caused by adsorption in the wastewater treatment plant can be predicted.

Fluoroquinolones (FQs) in the environment: A review on their abundance, sorption and toxicity in soil

The use of fluoroquinolones (FQs) antibiotics as therapeutic agents and growth promoters is increasing worldwide; however their extensive uses are also resulting in antibiotic resistance among world communities. FQs have also become one of the major contaminants in the waste water bodies, which are not even completely removed during the treatment processes. Furthermore, their abundance in agricultural resources, such as the irrigation water, the bio-solids and the livestock manure can also affect the soil micro-environment. These antibiotics in soil tend to interact in several different ways to affect soil flora and fauna. The current review endeavors to highlight the some critical aspects of FQs prevalence in the environment. The review presents a detailed discussion on the pathways and abundance of FQs in soil. The discussion further spans the issue of sorption and FQs transformation into the soil better understand of their behavior and their toxicity to soil flora and fauna.

A carbon nanotube-enhanced real-time immuno-PCR for ultrasensitive detection of AHTN in water

Polycyclic musks (PCMs) in the aquatic environment have become an emerging environmental issue because of their potential risk. The most commonly used method for analysis of PCMs is gas chromatography-mass spectrometer (GC-MS) with different sample extractions, which are somewhat expensive to operate, laborious and complex. In this paper, a carbon nanotube-enhanced real time immuno-PCR was developed for ultrasensitive detection of AHTN in water for the first time. The SWCNTs were used to immobilize numerous amino-DNA and polyclonal antibody to form polyclonal antibody-CNTs-DNA conjugates, which were used as a signal-amplifier in the proposed immunoassay system. This proposed carbon nanotube enhanced real time immuno-PCR assay was used to determine AHTN in water samples ranging from 5 pg/L-0.1 ng/L; using sample size as low as 10 μL. This proposed carbon nanotube enhanced real time immuno-PCR is the most ultrasensitive one for determination of AHTN in water without pre-concentration or extractions; and it provide a potential way for ultra-trace AHTN detection in the aquatic environment.

Environmental risk assessment of polycyclic musks HHCB and AHTN in consumer product chemicals in China

An environmental risk assessment (ERA) framework was recently developed for consumer product chemicals in China using a tiered approach, applying an existing Chinese regulatory qualitative method in Tier Zero and, then, utilizing deterministic and probabilistic methods for Tiers One and Two. The exposure assessment methodology in the framework applied conditions specific to China including physical setting, infrastructure, and consumers' habits and practices. Furthermore, two scenarios were identified for quantitatively assessing environmental exposure: (1) Urban with wastewater treatment, and; (2) Rural without wastewater treatment (i.e., direct-discharge of wastewater). Upon a brief discussion on the framework methodology, this paper primarily presented a case study conducted using this new approach for assessing two fragrance chemicals, the polycyclic musks HHCB (Galaxolide, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[gamma]-2-benzopyran) and AHTN (Tonalide, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene). Both HHCB and AHTN are widely used as fragrances in a variety of consumer products in China, and occurrences of both compounds have been reported in wastewater influents, effluents, and sludge, in addition to surface water and sediments across several major metropolitan regions throughout China. This case study illustrated the very conservative nature of Tier Zero, which indicated a high risk potential of the fragrances to receiving water aquatic communities due to the fragrance's non-ready biodegradability and eco-toxicity profiles. However, the higher-tiered assessments (including deterministic and site-specific probabilistic) demonstrated greater environmental realism with the conclusion of HHCB and AHTN posing minimal risk, consistent with local monitoring data as well as a recent similar study conducted in the United States.

Occurrences and removal of pharmaceuticals and personal care products (PPCPs) in drinking water and water/sewage treatment plants: A review

In recent years, many of micropollutants have been widely detected because of continuous input of pharmaceuticals and personal care products (PPCPs) into the environment and newly developed state-of-the-art analytical methods. PPCP residues are frequently detected in drinking water sources, sewage treatment plants (STPs), and water treatment plants (WTPs) due to their universal consumption, low human metabolic capability, and improper disposal. When partially metabolized PPCPs are transferred into STPs, they elicit negative effects on biological treatment processes; therefore, conventional STPs are insufficient when it comes to PPCP removal. Furthermore, the excreted metabolites may become secondary pollutants and can be further modified in receiving water bodies. Several advanced treatment systems, including membrane filtration, granular activated carbon, and advanced oxidation processes, have been used for the effective removal of individual PPCPs. This review covers the occurrence patterns of PPCPs in water environments and the techniques adopted for their treatment in STP/WTP unit processes operating in various countries. The aim of this review is to provide a comprehensive summary of the removal and fate of PPCPs in different treatment facilities as well as the optimum methods for their elimination in STP and WTP systems.

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.

Screening of organic pollutants in urban wastewater treatment plants and corresponding receiving waters

There is a lack of knowledge in environmental pollution of the anthropogenic contaminants in wastewater and surface water. Several organic compounds merit special attention, because of their potential risk to the aquatic environment. Therefore, gas chromatography-mass spectrometry-based screening analyses were performed in order to identify anthropogenic organic contaminants and to reveal information on the structural diversity of individual compounds and to characterize their environmental behavior. Wastewater samples from wastewater treatment plants in Germany, representing various capacities, and surface water samples from corresponding receiving waters were analyzed. Numerous substances were identified in the samples. Several compounds were treated inadequately during wastewater treatment, and their identification in surface waters highlights their potential impact on the aquatic environment. Contaminants were selected according to available information about their environmental relevance (e.g. persistence, bioaccumulation potential), their possible application or usage and their occurrence within the environment. Based on the results of this study, it is recommended that non-target screening analyses be undertaken to identify the structural diversity of anthropogenic organic contaminants and that further investigations of specific anthropogenic compounds be undertaken as a high priority.

Industrial release of fluoroquinolones (FQs) in the waste water bodies with their associated ecological risk in Pakistan

The unchecked production and use of fluoroquinolones (FQs) for the treatment of infections in human and livestock has increased in Pakistan, which resulted in large amount of antibiotics in water bodies. In the current study, the prevalence and associated ecological risk of three FQs were investigated in waste-water bodies and sludge samples of Kahuta and Hattar industrial zones. The average concentrations of ciprofloxacin (CIP), enrofloxacin (ENR) and levofloxacin (LEV) in the waste-water samples were slightly higher in Kahuta (i.e. 58, 32.9, and 36.7μgL^-1 respectively), than those in Hattar sites (i.e. 42.1, 41.2, and 48.9μgL^-1 respectively). However, the concentrations of CIP, ENR and LEV in the sludge samples were significantly higher (i.e. 159; 153 and 164μgkg^-1 respectively) in Hattar sites, compared to those in Kahuta sites (i.e. 129, 58 and 91μgkg^-1 respectively). The uses of FQs in the health sector resulted in water pollution and poses the ecological risk to aquatic organisms. The individual risk associated with CIP was highest in Kahuta industrial sites for green algae ranging (2900-9100) followed by M. aeruginosa (5800-18200), cyanobacteria (580-18204) and invertebrates (24.2-75.8). These values suggested that the prevalence of antibiotics in the waste-disposal sites could be potential risk for the aquatic ecosystem, and harmful to biodiversity.

Bioaccumulation and ecotoxicity increase during indirect photochemical transformation of polycyclic musk tonalide: A modeling study

Polycyclic musks (PCMs) have recently caused a worldwide environmental concern due to their bioaccumulation potential and ecotoxicological effects. Herein, the OH-initiated indirect photochemical transformation mechanism, environmental fate and ecotoxicity of PCMs (by taking tonalide as an example) were theoretically studied. Results show that tonalide can be degraded readily through OH-addition and H-abstraction pathways, with total rate constants of 6.03 × 10⁹-15.8 × 10⁹ M^-1 s^-1. The OH-addition pathways were dominant at low temperature (<∼287 K), whereas H-abstraction was the dominant pathway at high temperature. Further, the bioconcentration factors (BCF) and aquatic toxicities to fish of all transformation products from H-abstraction pathways were smaller than tonalide. In contrast, these values of most intermediates from OH-addition pathways were up to 8 times higher than tonalide. Particularly, the resultant phenolic product PC1 had a BCF of 5590 L/kg wet-wt, which exceeds the cutoff criterion set for the typically persistent organic pollutants as critically bioaccumulative. Notably, PC1 would mainly be produced under anaerobic aquatic conditions at low temperatures. Therefore, particular attention should be paid to the indirect photochemical products and parental PCMs, particularly the intermediates from OH-addition pathway.

Organic Contaminants in Chinese Sewage Sludge: A Meta-Analysis of the Literature of the Past 30 Years

The production of sewage sludge is increasing in China but with unsafe disposal practices, causing potential risk to human health and the environment. Using literature from the past 30 years (N = 159), we conducted a meta-analysis of organic contaminants (OCs) in Chinese sludge. Most data were available from developed and populated regions, and no data were found for Tibet. Since 1987, 35 classes of chemicals consisting of 749 individual compounds and 1 mixture have been analyzed, in which antibiotics and polycyclic aromatic hydrocarbons (PAHs) were the most targeted analytes. For 13 classes of principal OCs (defined as chemicals detected in over five studies) in sludge, the median (expressed in nanograms per gram dry weight) was the highest for phthalate esters (27 900), followed by alkylphenol polyethoxylates (12 000), synthetic musks (5800), antibiotics (4240), PAHs (3490), ultraviolet stabilizers (670), bisphenol analogs (160), organochlorine pesticides (110), polybrominated diphenyl ethers (100), pharmaceuticals (84), hormones (69), perfluorinated compounds (21), and polychlorinated biphenyls (15). Concentrations of PAHs in sludges collected between 1998 and 2012 showed a decreasing trend. Study findings suggest the need for a Chinese national sewage sludge survey to identify and regulate toxic OCs, ideally employing both targeted as well as nontargeted screening approaches.

The Influence of Suspended Solids on the Combined Toxicity of Galaxolide and Lead to Daphnia magna

Polycyclic musks and heavy metals are often present in natural aquatic environment. The aims of this study were to evaluate the toxic effects on Daphnia magna from exposure to the polycyclic musks and the heavy metals in combination with stress from suspended solids exposure. Galaxolide and lead were used as typical pollutants. The toxic effects on D. magna decreased with addition of suspended solids within the single experiments having galaxolide after 24 and 48 h. A similar result was observed for the toxic effect of lead on the D. magna with adding suspended solids during exposure. Synergism on D. magna was found within the combined tests having galaxolide and lead during the 24 and 48 h exposure based on additive index analysis. The combined toxic effect of galaxolide and lead was significantly decreased by adding suspended solids. The results could provide useful information for the toxic risks assessments of surface aquatic systems.

Enantiomeric composition of polycyclic musks in sediments from the Pearl River and Suzhou Creek

Due to differences in stereostructure, enantiomeric compositions and enantiomeric ratios (ERs) of chiral compounds can be used to discriminate environmental processes such as abiotic and biotic degradation/transformation. In this study, the ERs of two chiral polycyclic musks, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), were investigated in the sediments of Zhujiang River and Dongjiang River in the Pearl River Delta (PRD), as well as in those of Suzhou Creek in Shanghai City. The results indicated that ER cis of HHCB varied significantly, ranging from 1.09 to 1.53 and 1.40 to 1.48 in the PRD and Suzhou Creek samples, respectively, whereas ER trans of HHCB exhibited limited variation, ranging from 0.98 to 1.10 and 0.98 to 1.05 for Pearl River and Suzhou Creek samples, respectively. In addition, ERs of AHTN varied substantially from 1.10 to 1.34 and 1.17 to 1.28 in the PRD and Suzhou Creek, respectively. These results suggest that HHCB in the sediment in the study area underwent biotic degradation and the preferential biotransformation isomer was (4R,7S)-HHCB, while AHTN simultaneously underwent a certain degree of biotic degradation/transformation.

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.

Inhibition of polyisoprenylated methylated protein methyl esterase by synthetic musks induces cell degeneration

Synthetic fragrances are persistent environmental pollutants that tend to bioaccumulate in animal tissues. They are widely used in personal care products and cleaning agents. Worldwide production of Galaxolide and Tonalide are in excess of 4500 tons annually. Because of their widespread production and use, they have been detected in surface waters and fish in the US and Europe. Consumption of contaminated water and fish from such sources leads to bioaccumulation and eventual toxicity. Since fragrances and flavors bear structural similarities to polyisoprenes, it was of interest to determine whether toxicity by Galaxolide and Tonalide may be linked with polyisoprenylated methylated protein methyl esterase (PMPMEase) inhibition. A concentration-dependent study of PMPMEase inhibition by Galaxolide and Tonalide as well as their effects on the degeneration of cultured cells were conducted. Galaxolide and Tonalide inhibited purified porcine liver PMPMEase with Ki values of 11 and 14 μM, respectively. Galaxolide and Tonalide also induced human cancer cell degeneration with EC50 values of 26 and 98 μM (neuroblastoma SH-SY5Y cells) and 58 and 14 μM (lung cancer A549 cells), respectively. The effects on cell viability correlate well with the inhibition of PMPMEase activity in the cultured cells. Molecular docking analysis revealed that the binding interactions are most likely between the fragrance molecules and hydrophobic amino acids in the active site of the enzyme. These results appear to suggest that the reported neurotoxicity of these compounds may be associated with their inhibition of PMPMEase. Exposure to fragrances may pose a significant risk to individuals predisposed to developing degenerative disorders.

Pharmaceuticals and personal care products in the aquatic environment in China: a review

Pharmaceuticals and personal care products (PPCPs) have been detected as contaminants of emerging concern ubiquitously in the aquatic environment in China and worldwide. A clear picture of PPCP contamination in the Chinese aquatic environment is needed to gain insight for both research and regulatory needs (e.g. monitoring, control and management). The occurrence data of 112 PPCPs in waters and sediments in China has been reviewed. In most cases, the detected concentration of these PPCPs in waters and sediments were at ng/L and ng/g levels, which were lower than or comparable to those reported worldwide. A screening level risk assessment (SLERA) identified six priority PPCPs in surface waters, namely erythromycin, roxithromycin, diclofenac, ibuprofen, salicylic acid and sulfamethoxazole. The results of SLERA also revealed that the hot spots for PPCP pollution were those river waters affected by the megacities with high density of population, such as Beijing, Tianjin, Guangzhou and Shanghai. Limitations of current researches and implications for future research in China were discussed. Some regulatory issues were also addressed.

Ecological risks of polycyclic musk in soils irrigated with reclaimed municipal wastewater

HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8-hexamethylcyclopenta-c-2-benzopyrane) and AHTN (7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene) are found in reclaimed municipal wastewater. They may accumulate in soils receiving long-term application of reclaimed water thus adversely impact the soil biota. We evaluated the extent of their accumulation in receiving soils using HYDRUS-1D based on reclaimed municipal wastewater irrigation data at a public park in Beijing. The potential for ecological harms were assessed according to tested and reported outcomes of acute toxicity tests using wheat (Triticum aetivum L), earthworm (Eisenia fetida) and springtail (Bourletiella hortensis) as target organisms. Results of comparison among EC50 values from wheat, earthworm and springtail showed the EC50 value for root elongation inhibition of wheat germination was the least. Based on the least EC50, predicted no effect concentration in soils were 290 and 320ng /g for HHCB and ATHN, respectively. Comparable results from simulation to experimental and field investigating date validated the using of HYDRUS-1D in the work. Results of risk prediction showed it would take 243 and 666 years for HHCB and AHTN accumulated in soils at current irrigation practice to reach the levels for the resulting risk characterization ratios (RCRs) to cause potential ecosystem harms.

Fate and removal of typical pharmaceuticals and personal care products by three different treatment processes

The presence and distribution of typical of pharmaceuticals and personal care products (PPCPs), which comprise two types of polycyclic musks (PCMs) including Galaxolide (HHCB) and Tonalide (AHTN) as well as six types of estrogens containing estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethynylestradiol (EE2), diethylstilbestrol (DES), and bisphenol A (BPA), were investigated at two wastewater treatment plants (WWTPs) in Jiangsu, China. Only raw wastewater was treated in WWTP A while WWTP B was serving an urban-industrialized area. In the influent, the concentrations of EE2 (2193-4437ngL(-1)), E2 (1126-1170ngL(-1)), and DES (268-421ngL(-1)) were generally higher than the previously reported values, whereas the concentrations of HHCB (306-316ngL(-1)), E1 (29-129ngL(-1)), E3 (53ngL(-1)), and BPA (26-176ngL(-1)) were much lower than those reported in other previous studies. In addition, AHTN was not detected in either WWTP and E3 was not found in WWTP B. The detected processes including anaerobic/oxic process (A/O), combined orbal oxidation ditch process (C-orbal OD) and anaerobic/anoxic/anoxic/oxic membrane biological reactor (A/A/A/O-MBR) showed higher removal efficiencies for HHCB (67-71%) and EE2 (87%) than those in other previous studies. Besides, the total hydraulic retention time (HRT) ranged between 6.7 and 20.0h, sludge retention time (SRT) ranged between 8 and 23d, and water temperature ranged from 24.8 to 28.2°C. The removal efficiencies for estrogens in biological processes were related to the following factors: the level of hydrophobic estrogens, the type of removal process (C-orbal OD was consistently less efficient in removing estrogens than A/O and A/A/A/O-MBR), and a high SRT or HRT (A/A/A/O-MBR with higher SRT and HRT showed higher and more stable removal of hydrophobic estrogens).

Occurrence, distribution and potential affecting factors of antibiotics in sewage sludge of wastewater treatment plants in China

The occurrence and distribution of eight quinolones, nine sulfonamides, and five macrolides were investigated in sewage sludge from 45 wastewater treatment plants in 23 cities in China. Among all the antibiotics considered, quinolones were the dominant antibiotics detected in all samples [total concentrations up to 8905 μg/kg, dry weight (dw)], followed by macrolides (85.1 μg/kg, dw), and sulfonamides (22.7 μg/kg, dw). High concentrations of quinolones in sewage sludge indicated that antibiotics are widely used and extensive pollutants in China. Significant differences were observed for the total concentrations of antibiotics in sludge samples among the 45 WWTPs. To evaluate the potential factors affecting the antibiotic levels in sewage sludge, wastewater and sludge characteristics, as well as the operational conditions and treatment techniques in WWTPs were investigated. The results indicated that the antibiotic levels in sewage sludge depend to a great extent on wastewater characteristics. Significant correlation between total organic carbon (TOC) and total concentrations of antibiotics was also found in studied WWTPs, indicating that TOC could affect the sludge adsorption capability to the antibiotics to some extent. Moreover, the relation between treatment techniques and the total concentrations of antibiotics in sludge showed that antibiotic levels in sludge increased with longer solid retention time.

Occurrence of polycyclic musks in wastewater and receiving water bodies and fate during wastewater treatment

The occurrence of cashmerane (DPMI), celestolide, phantolide, traesolide (ATII), galaxolide (HHCB) and tonalide (AHTN) in sewage and surface waters and their fate during wastewater treatment and anaerobic sludge digestion is investigated. AHTN and HHCB are the most important representatives and influent concentrations of 0.41-1.8 and 0.9-13 μgL(-1) are observed. DPMI is detected in influent and effluent samples but in notably lower concentrations than AHTN and HHCB. Major sources of polycyclic musks are households, whereas industrial emitters seem to be of minor importance. This conclusion is supported by the analysis of selected industrial wastewaters (metal, textile and paper industry). Specific emissions of 0.36 ± 0.19 and 1.6 ± 1.0 mg cap(-1)d(-1) for AHTN and HHCB are calculated. Overall removal efficiencies between approx 50% and more than 95% are observed during biological wastewater treatment and removal with the excess sludge is the major removal pathway. Log K(D) values of 3.73-4.3 for AHTN, 3.87-4.34 for HHCB and 2.42-3.22 for DPMI are observed in secondary sludge. During sludge digestion no or only slight removal occurred. Mean polycyclic musk concentrations in digested sludge amounted to 1.9 ± 0.9 (AHTN), 14.2 ± 5.8 (HHCB), 0.8 ± 0.4 (ATII) and 0.2 ± 0.09 (DPMI) mgkg(-1) dry matter. In the receiving water systems a comparable distribution as during wastewater treatment is observed. AHTN, HHCB and DPMI are detected in surface waters (ND (not detected) - <0.04, ND - 0.32 and ND - 0.02 μg L(-1)) as well as AHTN and HHCB in sediments (ND - 20, ND - 120 μg kg(-1)). For HHCB an apparent K(OC) value of 4.1-4.4 is calculated for sediments. Major source for polycyclic musks in surface waters are discharges from wastewater treatment plants. For HHCB and DPMI 100% of the load observed in the sampled surface waters derive from discharges of treated wastewater.

Elimination and fate of selected micro-organic pollutants in a full-scale anaerobic/anoxic/aerobic process combined with membrane bioreactor for municipal wastewater reclamation

The occurrence and elimination of 19 micro-organic pollutants including endocrine disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) in a full-scale anaerobic/anoxic/aerobic-membrane bioreactor process was investigated. The investigated process achieved over 70% removal of the target EDCs and 50%-100% removal of most of the PPCPs, with influent concentration ranging from ng/L to μg/L. Three PPCPs, carbamazepine, diclofenac and sulpiride were not well removed, with the removal efficiency below 20%. A rough mass balance suggests that the targets were eliminated through sludge-adsorption and/or biodegradation, the former of which was particularly significant for the removal of hydrophobic compounds. The two-phase fate model was employed to describe the kinetics of sludge-adsorption and biodegradation. It was found that the fast sludge adsorption (indicated by mass-transfer rates greater than 10 for most compounds) is responsible for the rapid decline of the aqueous concentration of the targets in the first compartment of the treatment process (i.e. in the anaerobic tank). In contrast, the slow biodegradation proved to be the rate-determining step for the entire degradation process, and the rates are generally positively related to the dissolved oxygen level. On the other hand, this study showed that the removal rates of most targets can reach a quasi-plateau in 5 h under aerobic conditions, indicating that hydraulic retention time of ca. 5 h in aerobic tanks should be sufficient for the elimination of most targets.

Occurrence of synthetic musk fragrances in human blood from 11 cities in China

We measured two nitro musk fragrances (musk xylene) and musk ketone) and five polycyclic musk fragrances (galaxolide [HHCB], tonalide [AHTN], celestolide [ADBI], traseolide [ATII], and phantolide [AHMI]) in human blood samples from 11 cities of China (n = 204). Possible temporal trends in musk concentrations and associations with personal factors, such as gender, age, and others, were studied. Galaxolide (HHCB) showed the highest median concentration (0.85 ng/g) followed by AHTN (0.53 ng/g) with high detection frequency (91 and 77%, respectively). Concentrations of the other synthetic musk fragrances, including musk ketone and musk xylene, were all below the quantification limits. The results suggested that musk concentrations were not significantly relative to gender and body weight but positively correlated with age groups and locations. Apparent differences were also observed in the ratios of HHCB to AHTN concentrations among different cities.

Occurrence of xenobiotics in gray water and removal in three biological treatment systems

Eighteen selected xenobiotics related to personal care and household chemicals (UV-filters, fragrances, preservatives, biocides, surfactants) were measured in gray water from 32 houses and in effluents of three different biological treatment systems (aerobic, anaerobic, and combined anaerobic+aerobic). All selected xenobiotics were detected in gray water samples in the low microg L(-1) range. Generally, lower concentrations were measured after biological treatment and removal efficiencies were higher under aerobic conditions than under anaerobic conditions. However, most of the xenobiotics were still detected in biologically treated gray water. The most persistent compounds were the fragrance tonalide and the UV-filters 2-phenyl-5-benzimidazolesulfonic acid and ethylhexyl methoxycinnamate. Estimated estrogenic potential of the effluent ranged between 0.07 and 0.72 ng L(-1) of 17beta-estradiol equivalents. Depending on the application of the effluent and its environmental risk, physical-chemical processes might be required to increase the removal efficiency of these compounds from gray water.