Occurrence, phase distribution, and mass loadings of benzothiazoles in riverine runoff of the Pearl River Delta, China

Occurrence, removal, and fate of benzothiazoles (BTHs) and benzotriazoles (BTRs) in two wastewater treatment plants in New York State, USA

Benzothiazoles (BTHs) and benzotriazoles (BTRs) are widely used in various consumer products. However, their occurrence and fate in wastewater treatment plants (WWTPs) in the United States remain poorly understood. In this study, wastewater and sludge samples were collected from two WWTPs from the Albany area of New York State (WWTPA and WWTPB) and the concentrations of three BTH derivatives (BTH, 2-OH-BTH, and 2-Me-S-BTH) and five BTR derivatives (1-OH-BTR, XTR, 4-OH-BTR, TTR, and BTR) were determined. The geometric mean (GM) concentrations of Σ(BTHs) and Σ(BTRs) in influent were in the range of 7550-8690 and 4590-6240 ng/L, whereas those in effluent were 6650-7150 and 4620-6800 ng/L, respectively. In the influent of two WWTPs, BTH, BTR, and TTR were identified as the major chemicals at respective GM concentrations of 8440, 4200, and 1280 ng/L in WWTPA, and 7300, 1180, and 2090 ng/L in WWTPB. The removal efficiencies of BTHs and BTRs following activated sludge treatment were < 80 %, and Σ(BTRs) showed a negative removal in both WWTPs. The respective mass loadings of Σ(BTHs) and Σ(BTRs) were 7240 and 5200 mg/d/1000 individuals in WWTPA, and 3530 and 2140 mg/d/1000 individuals in WWTPB. The environmental emissions of Σ(BTHs) and Σ(BTRs) from WWTP discharges were estimated at 3110-6030 and 2160-5700 mg/d/1000 individuals, respectively. Overall, BTHs and BTRs are not efficiently removed in WWTP processes. This study provides baseline information regarding the loading, fate, and discharge of BTHs and BTRs from WWTPs in the USA.

Distribution and source analysis of soil toxic organic compounds of coal-electricity production base in arid and semi-arid region of China

The presence and distribution of toxic organic compounds in soil pose significant challenges. Whether their distributional characteristics are more complex, especially in arid and semi-arid regions with harsh climatic conditions? This study analyzed the composition, classification, spatial distribution, and sources of 123 toxic organic compounds in 56 soil samples of coal-electricity production base. Those compounds were classified into 11 categories, mainly pesticides (41 compounds), organic synthesis intermediates (31 compounds), and drugs (23 compounds). Seventeen of those compounds were detected over the rate of 30 %, with 13 of them being under the Toxic Substances Control Act (TSCA) inventory. The primary sources of toxic organic compounds were determined using Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF), including the degradation of pesticide residues (22.03 %), emissions of plastic pellets (16.64 %), industrial waste emissions (12.80 %), emissions from livestock (12.74 %), plastic films (11.22 %) and coal-to-liquid projects (10.78 %). This research underscores the widespread presence of toxic organic compounds in soil, highlighting their origins and distribution patterns, which are essential for developing targeted environmental management strategies in arid and semi-arid regions.

Non-targeted screening and photolysis transformation of tire-related compounds in roadway runoff

Roadway runoff serves as a crucial pathway for transporting contaminants of emerging concern (CECs) from urban environments to receiving water bodies. Tire-related compounds originating from tire wear particles (TWPs) have been frequently detected, posing a potential ecological threat. Yet, the photolysis of tire-related compounds within roadway runoff remains inadequately acknowledged. Addressing this deficit, our study utilized high-resolution mass spectrometry (HRMS) to characterize the chemical profile of roadway runoff across eight strategically selected sites in Guangzhou, China. 219 chemicals were identified or detected within different confidence levels. Among them, 29 tire-related contaminants were validated with reference standards, including hexa(methoxymethyl)melamine (HMMM), 1,3-diphenylguanidine (DPG), dicyclohexylurea (DCU), and N-cyclohexyl-2-benzothiazol-amine (DCMA). HMMM exhibited with the abundance ranging from 2.30 × 104-3.10 × 106, followed by DPG, 1.69 × 104-8.34 × 106. Runoff sample were exposed to irradiation of 500 W mercury lamp for photodegradation experiment. Photolysis results indicated that tire-related compounds with a low photolysis rate, notably DCU, DCMA, and DPG, are more likely to persist within the runoff. The photolytic rates were significantly correlated with the spatial distribution patterns of these contaminants. Our findings underscore TWPs as a significant source of pollution in water bodies, emphasizing the need for enhanced environmental monitoring and assessment strategies.

Features of the highway road network that generate or retain tyre wear particles

The environmental accumulation of microplastics poses a formidable global challenge, with tyre wear particles (TWPs) emerging as major and potentially harmful contributors to this particulate pollution. A critical pathway for TWPs to aquatic environments is via road drainage. While drainage assets are employed worldwide, their effectiveness in retaining microplastics of highly variable densities (TWP ~ 1-2.5 g cm3) remains unknown. This study examines their ability to impede the transfer of TWPs from the UK Strategic Road Network (SRN) to aquatic ecosystems. Samples were collected from the influent, effluent and sediments of three retention ponds and three wetlands. The rate of TWP generation is known to vary in response to vehicle speed and direction. To ascertain the significance of this variability, we further compared the mass of TWPs in drainage from curved and straight sections of the SRN across eight drainage outfalls. Pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) was used to quantify tyre wear using benzothiazole as a molecular marker for TWPs (with an internal standard benzothiazole-D4). Tyre wear was present in drainage from the SRN at concentrations of 2.86 ± 6 mg/L and was found within every sample analysed. Drainage from curved sections of the SRN contained on average a 40% greater TWP mass than straight sections but this was not significant. The presence of wetlands and retention ponds generally led to a reduction in TWP mass (74.9% ± 8.2). This effect was significant for retention ponds but not for wetlands; most probably due to variability among sites and sampling occasions. Similar drainage assets are used on a global scale; hence our results are of broad relevance to the management of TWP pollution.

Occurrence of traffic related trace elements and organic micropollutants in tunnel wash water

Substantially polluted tunnel wash water (TWW) is produced during road tunnel maintenance. Previous literature has reported the presence of trace elements and polycyclic aromatic hydrocarbons (PAHs). However, it was hypothesized that other organic pollutants are present, and more knowledge is needed to prevent environmental harm. This study reveals for the first time the presence of four short- and 17 long-chained per- and polyfluoroalkyl substances (PFASs), three benzothiazoles (BTHs), six benzotriazoles (BTRs), four bisphenols, and four benzophenones in TWW from a Norwegian road tunnel over a period of three years. Concentrations of PAHs, PFASs, BTHs, and BTRs were higher than previously reported in e.g., road runoff and municipal wastewater. Trace elements and PAHs were largely particulate matter associated, while PFASs, BTHs, BTRs, bisphenols, and benzophenones were predominantly dissolved. 26 of the determined contaminants were classified as persistent, mobile, and toxic (PMT) and are of special concern. It was recommended that regulations for TWW quality should be expanded to include PMT contaminants (such as PFPeA, PFBS, BTR, and 4-OH-BzP) and markers of pollution (like 2-M-BTH, 2-OH-BTH, and 2-S-BTH from tire wear particles). These findings highlight the need to treat TWW before discharge into the environment, addressing both, particulate matter associated and dissolved contaminants.

Occurrence and phase distribution of benzothiazoles in untreated highway stormwater runoff and road dust

The study about how tyre-derived particles can potentially worsen the water quality and how traffic pollution markers can affect the environment is crucial for environmental management. Road emissions are known to contribute to pollution in various environments, and benzothiazoles and their derivates can be used to trace pollutant inputs related to surface runoff in the aquatic system. A total of eight benzothiazoles were determined in highway stormwater runoff and road dust collected from February to August 2022 near Venice (Casale sul Sile, Veneto Region, Italy). A new analytical method was validated, by using an UHPLC system coupled to a mass spectrometer (triple quadrupole). The target compounds were determined in both dissolved phase and suspended particulate matter of runoff, and the road dust samples were divided into seven fractions depending on particle diameters to understand the fraction partitioning. The results indicate that 2-SO3H-BTH was the most concentrated benzothiazole in all the analysed substrates, suggesting tyre debris as the main source because it is usually used in the vulcanization process. 2-SO3H-BTH reached a mean concentration of 115 ± 59 µg L-1, 4 ± 3 µg L-1, and 411 ± 441 µg Kg-1 for dissolved phase, suspended particulate matter, and road dust, respectively, while 2-OH-BTH and BTH showed values about an order of magnitude lower. The size distribution of most BTHs suggests that they are distributed in the finest fraction of road dust. An exception was given by 2-SCNMeS-BTH being present only in particles with a diameter > 1 mm.

Identification and quantification of tire wear particles by employing different cross-validation techniques: FTIR-ATR Micro-FTIR, Pyr-GC/MS, and SEM

Tire wear particles (TWPs) are one of the environment's most important emission sources of microplastics. In this work, chemical identification of these particles was carried out in highway stormwater runoff through cross-validation techniques for the first time. Optimization of a pre-treatment method (i.e., extraction and purification) was provided to extract TWPs, avoiding their degradation and denaturation, to prevent getting low recognizable identification and consequently underestimates in the quantification. Specific markers were used for TWPs identification comparing real stormwater samples and reference materials via FTIR-ATR, Micro-FTIR, and Pyrolysis-gas-chromatography-mass spectrometry (Pyr-GC/MS). Quantification of TWPs was carried out via Micro-FTIR (microscopic counting); the abundance ranged from 220,371 ± 651 TWPs/L to 358,915 ± 831 TWPs/L, while the higher mass was 39,6 ± 9 mg TWPs/L and the lowest 31,0 ± 8 mg TWPs/L. Most of the TWPs analyzed were less than 100 μm in size. The sizes were also confirmed using a scanning electron microscope (SEM), including the presence of potential nano TWPs in the samples. Elemental analysis via SEM supported that a complex mixture of heterogeneous composition characterizes these particles by agglomerating organic and inorganic particles that could derive from brake and road wear, road pavement, road dust, asphalts, and construction road work. Due to the analytical lack of knowledge about TWPs chemical identification and quantification in scientific literature, this study significantly contributes to providing a novel pre-treatment and analytical methodology for these emerging contaminants in highway stormwater runoff. The results of this study highlight the uttermost necessity to employ cross-validation techniques, i.e., FTIR-ATR, Micro-FTIR, Pyr-GC/MS, and SEM for the TWPs identification and quantification in the real environmental samples.

Chemical composition and potential health risks of tire and road wear microplastics from light-duty vehicles in an urban tunnel in China

Tire and road wear microplastics (TRWMPs) are one of the main non-exhaust pollutants of motor vehicles, which cause serious environmental and health issues. Here, TRWMPs in PM_2.5 samples were collected in a tunnel in urban Xi'an, northwest China, during four periods [I: 7:30-10:30, II: 11:00-14:00, III: 16:30-19:30, IV: 20:00-23:00 local standard time (LST)] in summer of 2019. The chemical components of rubbers, benzothiazoles, phthalates, and amines in TRWMPs were quantified, with a total concentration of 6522 ± 1455 ng m^-3 (mean ± standard deviation). Phthalates were predominant in TRWMPs, accounting for 64.8% on average, followed by rubbers (33.2%) and benzothiazoles (1.19%). The diurnal variations of TRWMPs showed the highest concentration in Period III (evening rush hour) and the lowest concentration in Period I (morning rush hour), which were not exactly consistent with the variation of the number of light-duty vehicles passed through the tunnel. The result implied that the number of vehicles might not be the most important contributor to TRWMPs concentration, whereas meteorological variables (i.e., precipitation, and relative humidity), vehicle speed, vehicle class, and road cleaning also affected their abundances. The non-carcinogenic risk of TRWMPs in this study was within the international safety threshold, but their carcinogenic risk exceeded the threshold by 2.7-4.6 times, mostly dominated by bis(2-ethylhexyl)phthalate (DEHP). This study provides a new basis for the source apportionment of urban PM_2.5 in China. The high concentrations and high potential cancer risks of TRWMPs represent the requirement for more efficient measures to control light-duty vehicle emissions.

Silent Contamination: The State of the Art, Knowledge Gaps, and a Preliminary Risk Assessment of Tire Particles in Urban Parks

Tire particles (TPs) are one of the main emission sources of micro- and nano-plastics into the environment. Although most TPs are deposited in the soil or in the sediments of freshwater and although they have been demonstrated to accumulate in organisms, most research has focused on the toxicity of leachate, neglecting the potential effects of particles and their ecotoxicological impact on the environment. In addition, studies have focused on the impact on aquatic systems and there are many gaps in the biological and ecotoxicological information on the possible harmful effects of the particles on edaphic fauna, despite the soil ecosystem becoming a large plastic sink. The aim of the present study is to review the environmental contamination of TPs, paying particular attention to the composition and degradation of tires (I), transport and deposition in different environments, especially in soil (II), the toxicological effects on edaphic fauna (III), potential markers and detection in environmental samples for monitoring (IV), preliminary risk characterization, using Forlanini Urban Park, Milan (Italy), as an example of an urban park (V), and risk mitigation measures as possible future proposals for sustainability (VI).

Enhanced Formation of 6PPD-Q during the Aging of Tire Wear Particles in Anaerobic Flooded Soils: The Role of Iron Reduction and Environmentally Persistent Free Radicals

Rapid urbanization drives increased emission of tire wear particles (TWPs) and the contamination of a transformation product derived from tire antioxidant, termed as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q), with adverse implications for terrestrial ecosystems and human health. However, whether and how 6PPD-Q could be formed during the aging of TWPs in soils remains poorly understood. Here, we examine the accumulation and formation mechanisms of 6PPD-Q during the aging of TWPs in soils. Our results showed that biodegradation predominated the fate of 6PPD-Q in soils, whereas anaerobic flooded conditions were conducive to the 6PPD-Q formation and thus resulted in a ∼3.8-fold higher accumulation of 6PPD-Q in flooded soils than wet soils after aging of 60 days. The 6PPD-Q formation in flooded soils was enhanced by Fe reduction-coupled 6PPD oxidation in the first 30 days, while the transformation of TWP-harbored environmentally persistent free radicals (EPFRs) to superoxide radicals (O2•-) under anaerobic flooded conditions further dominated the formation of 6PPD-Q in the next 30 days. This study provides significant insight into understanding the aging behavior of TWPs and highlights an urgent need to assess the ecological risk of 6PPD-Q in soils.

Prenatal exposure to benzotriazoles and benzothiazoles and child neurodevelopment: A longitudinal study

Benzotriazoles (BTRs) and benzothiazoles (BTHs) are emerging benzo-heterocyclic compounds that may induce neurotoxicity. However, the effect of prenatal exposure to BTs (BTRs and BTHs) on child neurodevelopment has not been elucidated. We aimed to explore the associations between maternal urinary concentrations of BTs in single or in mixture with child neurodevelopment at the age of two. This study recruited 513 mother-child pairs based on a birth cohort from 2014 to 2015 in Wuhan. Maternal urinary concentrations of eight BTs (four BTRs and four BTHs) in the first, second, and third trimesters were measured. The mental development index (MDI) and psychomotor development index (PDI) of children, as two indexes of neurodevelopment, were assessed at two years old by the Bayley Scales. In the analyses of single BTs, prenatal average tolyltriazole (TTR) exposure level was associated with decreased boys' MDI scores (β = -2.84, 95 % CI: -5.11, -0.57) and prenatal average 1-H-benzotriazole (1-H-BTR) exposure level was associated with decreased boys' PDI scores (β = -1.44, 95 % CI: -2.70, -0.17), respectively. Maternal urinary concentrations of benzothiazole (BTH) in the 1^st trimester (β = -1.79, 95 % CI: -2.78, -0.80), 2^nd trimester (β = -1.14, 95 % CI: -2.19, -0.09), and the prenatal average exposure (β = -2.15, 95 % CI: -3.69, -0.61) were also negatively associated with boys' PDI scores. However, no significantly negative association was observed among girls. In the further mixture analysis, the quantile g-computation model found a significant negative association between prenatal average concentrations of BTs in mixture and boys' PDI scores [β = -4.80 (95 % CI: -9.08, -0.52)], and BTH weighted the highest in the negative association. As far as we know, this is the first research to estimate the effect of prenatal exposure to BTs on child neurodevelopment. The findings showed that prenatal exposure to BTs was negatively associated with neurodevelopment among boys, suggesting that the associations may be modified by infant sex.

Screening p-Phenylenediamine Antioxidants, Their Transformation Products, and Industrial Chemical Additives in Crumb Rubber and Elastomeric Consumer Products

Recently, roadway releases of N,N'-substituted p-phenylenediamine (PPD) antioxidants and their transformation products (TPs) received significant attention due to the highly toxic 6PPD-quinone. However, the occurrence of PPDs and TPs in recycled tire rubber products remains uncharacterized. Here, we analyzed tire wear particles (TWPs), recycled rubber doormats, and turf-field crumb rubbers for seven PPD antioxidants, five PPD-quinones (PPDQs), and five other 6PPD TPs using liquid chromatography-tandem mass spectrometry. PPD antioxidants, PPDQs, and other TPs were present in all samples with chemical profiles dominated by 6PPD, DTPD, DPPD, and their corresponding PPDQs. Interestingly, the individual [PPDQ]/[PPD] and [TP]/[PPD] ratios significantly increased as total concentrations of the PPD-derived chemical decreased, indicating that TPs (including PPDQs) dominated the PPD-derived compounds with increased environmental weathering. Furthermore, we quantified 15 other industrial rubber additives (including bonding agents, vulcanization accelerators, benzotriazole and benzothiazole derivatives, and diphenylamine antioxidants), observing that PPD-derived chemical concentrations were 0.5-6 times higher than these often-studied additives. We also screened various other elastomeric consumer products, consistently detecting PPD-derived compounds in lab stoppers, sneaker soles, and rubber garden hose samples. These data emphasize that PPD antioxidants, PPDQs, and related TPs are important, previously overlooked contaminant classes in tire rubbers and elastomeric consumer products.

Simultaneous evaluation of benzotriazoles, benzothiazoles and benzenesulfonamides in water samples from the impacted urban Jacarepaguá Lagoon System (Rio de Janeiro, Brazil) by liquid chromatography coupled to electrospray tandem mass spectrometry

Benzotriazoles, benzothiazoles, and benzenesulfonamides are emerging pollutants stable in aquatic media emitted by anthropogenic sources. Selected compounds of these classes were evaluated in the impacted urban Jacarepaguá Lagoon System (JLS) located in a tropical coastal region of Rio de Janeiro City, Brazil that has experienced a rapid expansion of urban occupation and environmental degradation in recent decades, and it represents a pioneering study of these compounds carried out in Brazilian areas. A method of solid phase extraction followed by ultra-performance liquid chromatography coupled to electrospray tandem mass-spectrometry was implemented to evaluate water samples collected in different water bodies (rivers, lagoons, and channels) of the JLS from March 2017 to May 2018. Limits of quantification (LOQs) ≤ 10.0 ng L^-1, method linearity up to 1000 μg L^-1, and recoveries between 62 and 121 % at three different levels were obtained. Individual concentrations varied from < LOQ to 5260 ng L^-1 (benzotriazole, in May 2018) which also predominated in all river samples. 2-mercaptobenzothiazole predominated in samples taken in lagoons and channels in March 2017, and 2-aminobenzothiazole was never detected. River samples showed total concentrations up to 30 times larger in all sampling campaigns, except March 2017 when the sample taken at Tijuca Lagoon showed the largest total concentration of the compounds studied due to the largest concentration of 2-mercaptobenzothiazole (2505 ng L^-1) found in this study. Principal component analysis (PCA) using only composition data was unable to distinguish samples from rivers, and lagoons and channels, but a PCA combining composition data and environmental parameters (pH, Eh, dissolved O₂ concentration, temperature, salinity, and conductivity) discriminated the samples according to two groups: rivers and lagoons and channels. The Joá Channel flows directly to the open sea and our data allowed a (preliminary) estimation of the total mass flows of the studied compounds to the open sea, which would vary between 1702 g day^-1 (March 2017) to 106 g day^-1 (May 2018) and allowed a preliminary estimative based on the geometric mean of input of 87.9 kg year^-1, indicating the importance of the drainage area to the contamination of the coastal area, and consequently to ocean pollution.

Occurrence and removal of benzotriazole and benzothiazole in drinking water treatment plants

The occurrence and removal of four benzotriazoles (BTRs) and five benzothiazoles (BTHs) in drinking water treatment plants (DWTPs) and bottled water were investigated. The mean total BTR and BTH concentrations were 390 and 117 ng/L in raw water, 51.2 and 66.5 ng/L in treated water, and 0.758 and 48.4 ng/L in bottled water, respectively. Different distribution patterns were observed according to the water type, with the dominant BTR being 1H-BTR (mean: 57.8%) in raw water and a predominance of BTH in bottled water (mean: 84.6%). In the DWTPs, the mean removal of BTRs (90.9%) was better than that of BTHs (29.3%). The BTRs were efficiently removed in DWTPs, and in particular during adsorption processes. 5Cl-BTR had a high removal efficiency (75.7%) in the adsorption processes, followed by 5M-BTR (70.0%), 5,6-di-MeBTR (58.4%), and 1H-BTR (50.1%). By contrast, BTHs were not efficiently removed in DWTPs, although relatively high removal efficiencies were achieved with an ozonation process (43.1%) compared to other treatment processes. In treated drinking and bottled water, the hazard quotients (HQs) of the representative BTRs and BTHs were acceptable (defined as HQ < 1), with a safety margin of 2-5 orders of magnitude.

Aquatic environmental fates and risks of benzotriazoles, benzothiazoles, and p-phenylenediamines in a catchment providing water to a megacity of China

Wearing of vehicle parts could release many chemical additives into the environment, such as benzotriazoles (BTRs), benzothiazoles (BTHs), and p-phenylenediamines (PPDs), which are potentially toxic to wildlife and humans. This study investigated the occurrence, source, and risks of BTRs, BTHs, and PPDs in a source catchment providing water to Guangzhou, a megacity in South China, covering groundwater, surface water, and stormwater. The results showed that BTRs and BTHs were predominant in surface water and groundwater. Unexpectedly, the BTR and BTH concentrations were lower in surface water than groundwater in a third of the paired samples. For the first time, 6PPD-quinone, a toxic ozonation product of N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine (6PPD), was extensively detected in source waters. Stormwater decreased the BTR concentrations but increased the 6PPD-quinone concentrations in surface water owing to their affiliation to suspended particles. From natural to urban segments of Liuxi river, a downstream increasing trend in BTR and BTH concentrations was observed, confirming that they are indicative of urban anthropogenic activities. Strong correlations between industrial activities and BTR or BTH concentrations in surface water indicated that industrial activities were their main sources. Six compounds were prioritized as potentially persistent, mobile, and toxic (PMT) chemicals, combing our monitoring results and REACH criterion. This study improves our understanding of the environmental fates and risks of water-soluble tire-wear chemicals, which provides important information for chemical management, and indicates attention should be paid to the risk posed by 6PPD-quinone in the source water.

Occurrence and risks of 23 tire additives and their transformation products in an urban water system

Tire wear particles (TWPs) enter road surface with the friction between tires and road surfaces. Under the volatilization, leaching, and transformation action on TWPs by sunlight and rain, tire additives are released into urban water systems, such as surface rainfall runoff, wastewater treatment plants (WWTPs), receiving surface waters, and drinking water treatment plant (DWTP). In this study, we investigated the occurrence of 23 tire additives and their transformation products in the urban water system of the Pearl River Delta region, South China. Nineteen target compounds were detected in the surface runoff, with 1,3-Diphenylguanidine (DPG) showing highest maximum concentration of 58780 ng/L. Benzothiazole and its transformation products are detected at the frequency of 100 % with the total concentrations of 480-42160 ng/L. The antioxidant derivative N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) was also detected up to 1562 ng/L, which was considerably higher than that of the parent compound 6PPD (the maximum concentration of 7.52 ng/L). Eleven and 8 compounds were detected in WWTPs influents and effluents, respectively, with removal rates of - 62-100 %. Seventeen compounds were detected in the receiving Zhujiang and Dongjiang rivers, while 9 compounds were detected in drinking water sources and DWTP samples. Road runoff, with total concentrations of target compounds up to 79200 ng/L, is suggested as the main non-point source for receiving rivers, while WWTPs effluents are the point sources due to incomplete removal of target compounds after accepting the initial runoff. 6PPD-Q and other 10 compounds displayed median to high ecological risks in surface waters, and the human daily intake of tire additives was estimated to be 2.63 × 10^-8-3.16 × 10^-5 mg/(kg d) via drinking water. This is the first report of the 6PPD-Q and 1,3-Diphenylurea levels in surface waters in China.

Tyre additive chemicals, tyre road wear particles and high production polymers in surface water at 5 urban centres in Queensland, Australia

Plastics pollution is a global issue impacting every part of our environment. Tyre road wear particle (TRWP) plastics pollution is thought to be one of the largest pollution sources in urban environments. These plastics are also of concern due to the presence of additive chemicals, incorporated during manufacture, that can be released into the surrounding environment. This study aimed to provide information on concentrations of a range of anthropogenic plastics related pollutants in the Australian environment through a scoping study of surface water in 5 key urban centres around Queensland, Australia. Samples were analysed for a suite of 15 common tyre additive chemicals, TRWPs and 6 common high production polymers, and included the new transformation product of concern 6PPD-quinone which has recent reports of causing mass mortality events in certain aquatic species. The additives were ubiquitously detected (2.9-1440 ng/L) with 6PPD-quinone concentrations lower than in previous studies (<0.05-24 ng/L) and TRWPs detected at 18 of the 21 sites ( Collapse

Key Words

• 6PPD-quinone
• Microplastics
• Surface water pollution
• Tyre tread

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MESH Headings

• Australia
• Environmental Monitoring
• Environmental Pollutants
• Plastics
• Polyethylenes
• Polymers
• Polypropylenes
• Queensland
• Water
• Water Pollutants, Chemical
• Phenylenediamines
• Benzoquinones

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Grants Collapse

Affiliation(s)

Cassandra Rauert Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, 20 Cornwall Street, Woolloongabba, 4102, QLD, Australia.
Suzanne Vardy Water Quality and Investigation, Water Ecosystem Sciences, Science Division, Department of Environment and Science, Queensland Government, Dutton Park, QLD 4102, Australia
Benjamin Daniell Townsville City Council, Townsville, Australia
Nathan Charlton Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, 20 Cornwall Street, Woolloongabba, 4102, QLD, Australia
Kevin V Thomas Queensland Alliance for Environmental Health Sciences (QAEHS), The University of Queensland, 20 Cornwall Street, Woolloongabba, 4102, QLD, Australia

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Organophosphate tri-esters and di-esters in drinking water and surface water from the Pearl River Delta, South China: Implications for human exposure

Some organophosphate di-esters (di-OPEs) have been found to be more toxic than their respective tri-esters. The environmental occurrence of di-OPEs remains largely unclear. A total of 106 water samples, including 56 drinking water (bottled, barreled, and tap water) and 50 surface water (lake and river) samples were collected and analyzed for 10 organophosphate tri-esters (tri-OPEs) and 7 di-OPEs. The concentrations (range (median)) of ∑₇di-OPE were 2.8-22 (9.7), 1.1-5.8 (2.6), 3.7-250 (120), 13-410 (220), and 92-930 (210) ng/L in bottled water, barreled water, tap water, lake water, and river water, respectively. In all types of water samples, tris(1-chloro-2-propyl) phosphate was the dominant tri-OPE compound. Diphenyl phosphate was the predominant di-OPE compound in tap water and surface water, while di-n-butyl phosphate and bis(2-ethylhexyl) phosphate was the dominant compound in bottled water and barreled water, respectively. Source analysis suggested diverse sources of di-OPEs, including industrial applications, effluents of municipal wastewater treatment plants, degradation from tri-OPEs during production/usage and under natural environmental conditions. The non-carcinogenic and carcinogenic risks of OPEs were lower than the theoretical threshold of risk, indicating the human health risks to OPEs via drinking water consumption were negligible. More studies are needed to explore environmental behaviors of di-OPEs in the aquatic environment and to investigate ecological risks.

Occurrence and distribution of organic corrosion inhibitors (OCIs) in riverine sediments from the Pearl River Delta, South China

Although soluble organic corrosion inhibitors (OCIs) have been observed globally in surface water, data on their exposures in sediments are still scarce. In this study, a comprehensive investigation on spatial variations and potential sources of OCIs were conducted in riverine sediments from the Pearl River Delta (PRD), one of the most developed and urbanized areas in China. Of 12 OCIs, 7 were detected with the total concentrations ranging from 81.8 to 401.2 ng/g. When the results were compared with those of the water phase, OCIs in the riverine sediments exhibited relatively low concentrations, which was likely due to their low K_ow, and they were not expected to be adsorbed onto sediments. The spatial variation of OCIs suggested that the discharge of sewage treatment plants (STPs) effluent could be a major source of OCIs in the PRD region. The total concentrations of OCIs had a significant positive correlation with total organic carbon (TOC) contents, suggesting that they have similar sources. This study strongly indicated that the high consumption of OCIs have led to their wide exposure in different environments in the PRD region and additional ecotoxicological data are needed to evaluate their potential risks in riverine sediments in the future.

Associations of benzotriazoles and benzothiazoles with estrogens and androgens among pregnant women: A cohort study with repeated measurements

People are extensively exposed to benzotriazoles (BTRs) and benzothiazoles (BTHs) derivatives, which are environmental pollutants that may possess endocrine-disrupting potential; however, no epidemiological evidence is available on the associations of BTRs and BTHs with estrogens and androgens. This study aimed at investigating the associations of BTRs and BTHs with estrogens and androgens among pregnant women. Based on a prospective cohort study, we included 459 pregnant women who donated a complete serial of urine samples at each trimester and had repeated measurements of four BTRs, four BTHs, three estrogens (estrone, 17β-estradiol, and estrio), and two androgens (dehydroepiandrosterone and testosterone) in the urine samples. Associations of repeatedly measured BTRs and BTHs with maternal urinary estrogens and androgens were analyzed, and the cross-sectional associations were also analyzed. Tolyltriazole (TTR) (≥59.3%) and benzothiazole (BTH) (≥93.5%) had the highest detection rate among the BTRs and BTHs, respectively. Repeated measurement analysis and cross-sectional analysis consistently found the target BTRs and BTHs were positively associated with 17β-estradiol, estriol, and testosterone, while the trend of the associations with estrone and dehydroepiandrosterone was inconsistent. Among the positive associations with 17β-estradiol, estriol, and testosterone, the percent of change in estriol associated with TTR was the most prominent [28.5% (95% confidential interval: 24.2%, 32.9%) for each doubling in TTR]. The significant associations with estrone, estriol, testosterone, and dehydroepiandrosterone were stronger among pregnant women who gave birth to a boy than those who gave birth to a girl. These findings add epidemiological evidence on the endocrine-disrupting potential of BTRs and BTHs and highlight the importance of focusing on the health outcomes of BTRs and BTHs related to disturbed estrogens and androgens. Future studies are needed to validate these findings and explore the underlying mechanisms.

Degradation of benzothiazole pollutant by sulfate radical-based advanced oxidation process

Benzothiazole (BTH) is an aromatic heterocyclic compound with wide industrial applications. In view of its toxicity and wide environmental presence, previous efforts have been made to decompose BTH via different degradation pathways. However, due to its recalcitrant nature, conventional biological treatment methods cannot completely degrade BTH in the wastewater. In this study, sulfate radical-based advanced oxidation process (AOP) technique has been adopted to degrade BTH in aqueous phase. Persulfate (PS) was employed as radical promotor to generate sulfate radical via heat activation. Degradation of BTH by thermally activated persulfate via AOP has been experimentally evaluated in a systematic manner. Laboratory efforts have been made to examine the impact of a number of physiochemical parameters including the type of oxidants, reaction temperature, initial concentrations of PS and BTH, solution pH, and the presence of anionic species. It shows that a higher BTH degradation rate can be achieved by lowering BTH initial concentration or increasing PS concentration. Increasing solution pH or the presence of 10 mM of Cl^-, Br^-, CO32-, or HCO3- species can decrease BTH degradation rate. Furthermore, the primary radical(s) responsible for BTH degradation have been identified as sulfate radical at an acidic aqueous condition, and hydroxyl radical and sulfate radical combined at a basic condition. This study provides the necessary theoretical and technical foundations for BTH degradation via sulfate radical-based AOP technique. The conclusions from this study can substantially promote the field application of AOP, especially sulfate radical-based AOP technique, for BTH degradation in wastewater treatment process.

Effects of Polyester Fibers and Car Tire Particles on Freshwater Invertebrates

Microplastic ingestion has been shown for various organisms, but knowledge of the potential adverse effects on freshwater invertebrates remains limited. We assessed the ingestion capacity and the associated effects of polyester fibers (26-5761 µm) and car tire particles (25-75 µm) on freshwater invertebrates under acute and chronic exposure conditions. A range of microplastic concentrations was tested on Daphnia magna, Hyalella azteca, Asellus aquaticus, and Lumbriculus variegatus using water only (up to 0.15 g/L) or spiked sediment (up to 2 g/kg dry wt), depending on the habitat of the species. Daphnia magna did not ingest any fibers, but low levels of fibers were ingested by all tested benthic invertebrate species. Car tire particle ingestion rose with increasing exposure concentration for all tested invertebrates and was highest in D. magna and L. variegatus. In most cases, no statistically significant effects on mobility, survival, or reproductive output were observed after acute and chronic exposure at the tested concentrations. However, fibers affected the reproduction and survival of D. magna (no-observed-effect concentration [NOEC]: 0.15 mg/L) due to entanglement and limited mobility under chronic conditions. Car tire particles affected the reproduction (NOEC: 1.5 mg/L) and survival (NOEC: 0.15 mg/L) of D. magna after chronic exposure at concentrations in the same order of magnitude as modeled river water concentrations, suggesting that refined exposure and effect studies should be performed with these microplastics. Our results confirm that microplastic ingestion by freshwater invertebrates depends on particle shape and size and that ingestion quantity depends on the exposure pathway and the feeding strategy of the test organism. Environ Toxicol Chem 2022;41:1555-1567. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Synthetic microfibers and tyre wear particles pollution in aquatic systems: Relevance and mitigation strategies

Evidence shows that the majority of aquatic field microplastics (MPs) could be microfibers (MFs) which can be originated directly from massive sources such as textile production and shedding from garments, agricultural textiles and clothes washing. In addition, wear and tear of tyres (TRWPs) emerges as a stealthy major source of micro and nanoplastics, commonly under-sampled/detected in the field. In order to compile the current knowledge in regards to these two major MPs sources, concentrations of concern in aquatic environments, their distribution, bulk emission rates and water mitigation strategies were systematically reviewed. Most of the aquatic field studies presented MFs values above 50%. MPs concentrations varied from 0.3 to 8925 particles m^-3 in lakes, from 0.69 to 8.7 × 10⁶ particles m^-3 in streams and rivers, from 0.16 to 192000 particles m^-3 estuaries, and from 0 to 4600 particles m^-3 in the ocean. Textiles at every stage of production, use and disposal are the major source of synthetic MFs to water. Laundry estimates showed an averaged release up to 279972 tons year^-1 (high washing frequency) from which 123000 tons would annually flow through untreated effluents to rivers, streams, lakes or directly to the ocean. TRWPs in the aquatic environments showed concentrations up to 179 mg L^-1 (SPM) in runoff river sediments and up to 480 mg g^-1 in highway runoff sediments. Even though average TRWR emission is of 0.95 kg year^-1 per capita (10 nm- 500 μm) there is a general scarcity of information about their aquatic environmental levels probably due to no-availability or inadequate methods of detection. The revision of strategies to mitigate the delivering of MFs and TRWP into water streams illustrated the importance of domestic laundry retention devices, Waste Water Treatment Plants (WWTP) with at least a secondary treatment and stormwater and road-runoff collectors quality improvement devices.

Concentrations of Tire Additive Chemicals and Tire Road Wear Particles in an Australian Urban Tributary

Tire road wear particles (TRWPs) are one of the largest sources of microplastics to the urban environment with recent concerns as they also provide a pathway for additive chemicals to leach into the environment. Stormwater is a major source of TRWPs and associated additives to urban surface water, with additives including the antioxidant derivative N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-quinone) demonstrating links to aquatic toxicity at environmentally relevant concentrations. The present study used complementary analysis methods to quantify both TRWPs and a suite of known tire additive chemicals (including 6PPD-quinone) to an urban tributary in Australia during severe storm events. Concentrations of additives increased more than 40 times during storms, with a maximum concentration of 2760 ng/L for ∑15additives, 88 ng/L for 6PPD-quinone, and a similar profile observed in each storm. TRWPs were detected during storm peaks with a maximum concentration between 6.4 and 18 mg/L, and concentrations of TRWPs and all additives were highly correlated. Contaminant mass loads to this catchment were estimated as up to 100 g/storm for ∑15additives, 3 g/storm for 6PPD-quinone, and between 252 and 730 kg of TRWPs/storm. While 6PPD-quinone concentrations in this catchment were lower than previous studies, elevated concentrations post storm suggest prolonged aquatic exposure.

Utility of benzothiazoles as markers of tire-derived inputs to estuarine waters assessed by polyethylene sheets

Tire-derived particles and polyethylene (PE) debris co-exist in estuaries and potentially deteriorate water quality. Chemicals can be emitted from tire-derived particles and resorb to PE debris. However, there was lack of information about the interaction (e.g., sorption and desorption) between tire-derived chemicals and PE debris. By combining batch sorption and desorption experiments along with in situ field deployment of PE sheets, we examined the utility of benzothiazoles (BTZs) sorbed in PE as suitable markers of tire-derived inputs. The sorptive characteristics and PE-water partition coefficients (often designated as K_pew) of selected tire-derived marker candidates, i.e., polycyclic aromatic hydrocarbons (PAHs), benzothiophenes (BTPs) and BTZs, were measured. Moderately polar BTPs and BTZs (except for 2-(4-morpholinyl) benzothiazole) reached equilibrium within 2-8 days, compared to 20 days for nonpolar PAHs. The measure K_pew values and octanol-water partition coefficients of PAHs and BTZs were linearly correlated with each other (r² > 0.80; p < 0.05). The desorption potentiality of PAHs and BTZs from tire particles is consistent with the hydrophilic properties of the target chemicals, while desorption ratios of BTZs and PAHs are 25-87% and <20%, respectively. Samplers with PE sheets as the sorbent phase were deployed in Hailing Bay, an urbanized estuary in South China, to measure concentrations of PAHs, BTPs and BTZs. Benzothiazoles sorbed in PE samples were associated with the massive utilization of automobile tires, while PAHs were linked to the boat maintenance facilities and BTPs were not detected in any tire particle and field PE samples. Therefore sorbed BTZs in PE can potentially serve as chemical markers of tire-derived inputs to estuaries.

Facile synthesis of nitrogen and sulfur co-doped hollow microsphere polymers from benzothiazole containing wastewater for water treatment

Advanced oxidation is a very efficient method in wastewater treatment, but it is a waste of resources to directly oxide the high concentration of valuable organics into carbon dioxide and water. In this paper, the combination of persulfate and wet air oxidation was developed to recover organics from high concentration of wastewater, along with high mineralization of the residual organics. Nitrogen and sulfur co-doped hollow spherical polymers with narrow size distribution was recovered from the simulated benzothialzole (BTH) wastewater in this facile way, along with chemical oxygen demand (COD) removal rate higher than 90%. The formation route of the polymers was intensively studied based on detailed analysis of different kinds of reaction intermediates. The polymers can be further carbonized into co-doped hollow carbon microsphere, which showed better performance in organic contaminants removal than a commercial activated carbon both in adsorption or catalytic persulfate oxidation. This proposed a new strategy to simultaneously combine oxidation and polymerization for resource recovery from wastewater with high concentration of heterocyclic compounds.

Environmental occurrence, fate, impact, and potential solution of tire microplastics: Similarities and differences with tire wear particles

Tire microplastics (TMPs) are identified as one of the most abundant types of microplastics, which originate from rubber with intended or unintended release. While increasing knowledge about TMPs concentrates on tire wear particles (TWPs), TMPs from other potential sources like recycled tire crumb (RTC) and tire repair-polished debris (TRD) are much less understood. Excessive levels of TMPs and their additives have been fragmentarily reported in the environment. The accumulating environmental TMPs from different sources may directly or indirectly cause adverse impacts on the environment and human health. The objectives of this review are to (1) summarize the properties, abundance, and sources of TMPs in the environment; (2) analyze the environmental fates and behaviors of TMPs, including their roles in carrying abiotic and biotic co-contaminants; (3) evaluate the potential impacts of TMPs on terrestrial and aquatic organisms, as well as human; and (4) discuss the potential solutions to mitigate the TMP pollution. By collecting and analyzing the up-to-date literature, this review enhances our better understanding of the environmental occurrence, fates, impacts, and potential solutions of TMPs, and further highlights critical knowledge gaps and future research directions that require cooperative efforts of scientists, policymakers, and public educators.

Quantifying the release of tyre wear particles to the marine environment via multiple pathways

Desk-based studies have suggested tyre wear particles contribute a substantial portion of microplastic emissions to the environment, yet few empirical studies report finding tyre wear. Samples were collected from three pathways to the marine environment: atmospheric deposition, treated wastewater effluent, and untreated surface runoff. Pyrolysis coupled to gas chromatography-mass spectrometry was used to detect benzothiazole, a molecular marker for tyres. Benzothiazole was detected in each pathway, emitting tyre wear in addition to other sources of microplastics. Release via surface water drainage was the principle pathway in the regions examined. Laboratory tests indicated larger particles likely settle close to their entry points, whereas smaller particles have potential for longer-range transport and dispersal. The previous lack of reports are likely a consequence of inadequate methods of detection, rather than a low environmental presence. Further work is required to establish distribution, transport potential, and potential impacts once within the marine environment.

Determination of low-density polyethylene-water partition coefficients for novel halogenated flame retardants with the large volume model and co-solvent model

The partition coefficient (K_pew) of an analyte between low-density polyethylene (LDPE) film and water is a critical parameter for measuring freely dissolved concentrations of the analyte with PE passive sampling devices. Measuring log K_pew for super hydrophobic organic chemicals (HOCs) have been proven extremely difficult. The present study developed a large volume model for measuring log K_pew of super HOCs, i.e., novel halogenated flame retardants (NHFRs). Results showed that the measured log K_pew values of selected PAHs and PCBs obtained by the large volume model were in line with those from the co-solvent model and the literature data within less 0.3 log units of difference, while those of NHFRs (6.27-7.34) except for hexachlorocyclopentadienyldibromocyclooctane (HCDBCO) and Decabromodiphenyl ethane (DBDPE) were significantly lower than those (6.51-8.89) from the co-solvent model. A curvilinear relationship was observed between log K_pew and log K_ow of all target compounds, with the turning point at log K_ow = ∼8.0 in the large volume model, but that was not found for the co-solvent model. These can be attributed to the large molecular volumes (> 450 Å³) for NHFRs, which require high Gibbs free energy to penetrate into the inside structures of LDPE in the large volume model. However, the solvent swelling effects in the co-solvent model needs to be investigated. Therefore, the large volume model is robust to determine the K_pew values of super HOCs for facilitating the application of aquatic passive sampling techniques.

UV/chlorine process for degradation of benzothiazole and benzotriazole in water: Efficiency, mechanism and toxicity evaluation

Benzothiazole (BZA) and benzotriazole (BTZ) as emerging contaminants were found persistent in aquatic environments and toxic to aquatic organisms. The degradation of BZA and BTZ by UV/chlorine was systematically investigated in this study, and the results showed that BZA and BTZ can be remarkably removed by UV/chlorine compared with UV alone and dark chlorination. The radical quenching tests showed that degradation of BZA and BTZ by UV/chlorine involved the participation of reactive chlorine species (RCS), hydroxyl radical (HO·), and UV photolysis. HO· dominated BZA degradation at neutral and alkalinity, while RCS dominated BTZ degradation. The second-rate order constants for ClO· and BZA and BTZ were 2.22 × 10⁸ M^-1 s^-1, and 2.40 × 10⁸ M^-1 s^-1, respectively. Besides, the second-order rate constants for HO· and BZA and BTZ were also determined at pH 5.0, 7.0, and 9.0, respectively. The degradation efficiency of BZA by UV/chlorine was substantially promoted at acidic conditions, while the degradation efficiency of BTZ was promoted at both acidic and specific alkaline range mainly due to the reactivity of radical species and deprotonated form. The influence of Cl^- was negligible, but the suppression effect of humic acid was slight during the BZA and BZT degradation by UV/chlorine. The transformation products were detected and the possible pathways were proposed. Seven disinfection by-products (DBPs) were identified both in BZA and BTZ degradation and trichloromethane was the main DBP. The toxicity assessment performed by luminescent bacteria and ECOSAR analysis indicated that the detoxification of BZA could be achieved by UV/chlorine, whereas the toxicity of BTZ was increased mainly due to the formation of intermediates. The findings from this study demonstrated UV/chlorine is likewise efficient for BZA and BTZ removal but the toxicity should be considered in the BTZ degradation.

Contamination profiles and health impact of benzothiazole and its derivatives in PM2.5 in typical Chinese cities

Although benzothiazole and its derivatives (BTHs) are considered emerging contaminants in diverse environments and organisms, little information is available about their contamination profiles and health impact in ambient particles. In this study, an optimized method of ultrasound-assisted extraction coupled with the selected reaction monitoring (SRM) mode of GC-EI-MS/MS was applied to characterize and analyze PM_2.5-bound BTHs from three cities of China (Guangzhou, Shanghai, and Taiyuan) during the winter of 2018. The total BTH concentration (ΣBTHs) in PM_2.5 samples from the three cities decreased in the order of Guangzhou > Shanghai > Taiyuan, independently of the PM_2.5 concentration. Despite the large variation in concentration of ΣBTHs in PM_2.5, 2-hydroxybenzothiazole (OTH) was always the predominant compound among the PM_2.5-bound BTHs and accounted for 50-80% of total BTHs in the three regions. Results from human exposure assessment and toxicity screening indicated that the outdoor exposure risk of PM_2.5-bound BTHs in toddlers was much higher than in adults, especially for OTH. The developmental and reproduction toxicity of OTH was further explored in vivo and in vitro. Exposure of mouse embryonic stem cells (mESCs) to OTH for 48 h significantly increased the intracellular reactive oxygen species (ROS) and induced DNA damage and apoptosis via the functionally activating p53 expression. In addition, the growth and development of zebrafish embryos were found to be severely affected after OTH treatment. An overall metabolomics study was conducted on the exposed zebrafish larvae. The results indicated that exposure to OTH inhibited the phenylalanine hydroxylation reaction, which further increased the accumulation of toxic phenylpyruvate and acetylphenylalanine in zebrafish. These findings provide important insights into the contamination profiles of PM_2.5-bound BTHs and emphasize the health risk of OTH.

Deep eutectic solvent-based ultrasound-assisted emulsification microextraction for the rapid determination of benzotriazole and benzothiazole derivatives in surface water samples

This work describes a simple and environmental-friendly method for the simultaneous determination of five benzotriazole derivatives (BTRs) and four benzothiazole derivatives (BTs) that are frequently found in surface water. The target analytes were efficiently extracted from water samples using a "green" deep eutectic solvent (DES) as the extraction solvent based- ultrasound-assisted emulsification microextraction (DES-USAEME), and their determination were performed by ultrahigh-performance liquid chromatography and electrospray ionization (+)-quadrupole time-of-flight mass spectrometry (UHPLC-ESI(+)-QToF-MS). The DES was composed of a mixture of choline chloride and phenol (molar ratio 1:2). The DES-USAEME factors were optimized by a Box-Behnken Design coupled response surface methodology. The developed method was validated, providing limits of quantitation (LOQs; 02 μg L^-1), high precisions (1-8%), and satisfactory mean spiked recoveries (72-104 %). Relatively high total concentrations of the target analytes were found in samples collected from a reservoir (47.2-101.3 μg L^-1), which may have been released from tire-wear particles and scrap tires from buses and old tires that were strung alongside the shuttle boats to prevent the boats from coming into contact with each other or from impacting against the dock during docking. This is the first study on the occurrence of BTRs and BTs in reservoir samples.

Nontargeted identification and predicted toxicity of new byproducts generated from UV treatment of water containing micropollutant 2-mercaptobenzothiazole

Comprehensive identification of byproducts including intermediate transformation products (TPs) of micropollutants in source water is challenging and paramount for assessment of drinking water quality and treatment technologies. Here, we have developed a nontargeted analysis strategy coupled with computational toxicity assessment to identify indistinguishable TPs including isomers with large differences in toxicity. The new strategy was applied to study the UV treatment of water containing micropollutant 2-mercaptobenzothiazole (2-MBT), and it enabled successful identification of a total of 22 organic TPs. Particularly, the structures of nine new TPs were identified for the first time; in addition, three isomers (P2, P3, and P4) were distinguished from the toxic contaminant 2-hydroxybenzothiazole (2-OH-BT). Computational assessments indicate that estrogenic activity of the three isomers (P2-P4) is higher than that of 2-OH-BT. Mass balance study shows that the 22 organic products accounted for 70% of the 2-MBT degraded, while 30% may degrade to inorganic products. Most TPs are resistant to UV photolysis. Computational toxicity assessment predicted the TPs to increase inhibition of human thyroperoxidase activity although they have lower aquatic toxicity compared to original 2-MBT. This study emphasizes the importance of monitoring the 2-MBT photodegradation products and the overall toxicity of finished water whose production included a UV light-based treatment process.

Prenatal exposure to benzotriazoles and benzothiazoles and cord blood mitochondrial DNA copy number: A prospective investigation

BACKGROUND

Mitochondria are sensitive to environmental toxicants due to the limited repair capacity. Exposure to benzotriazoles (BTRs) and benzothiazoles (BTHs) may contribute to adverse health outcomes through oxidative stress, which may interfere with mitochondrial function. However, the mitochondrial effects of exposure to BTs (BTRs and BTHs) have not yet been elucidated, particularly in human investigations.

OBJECTIVES

We examined the associations between trimester-specific urinary BTRs and BTHs concentrations and cord blood mitochondrial DNA copy number (mtDNAcn) in a prospective birth cohort.

METHODS

The present study included 742 mother-infant pairs who participated in a birth cohort between 2014 and 2015 in Wuhan and had data on urinary concentrations of BTRs and BTHs and mtDNAcn in cord blood. Concentrations of BTs were repeatedly measured in maternal urine samples at different trimesters using high performance liquid chromatography-tandem mass spectrometry. Relative mtDNAcn in umbilical cord blood was analyzed by quantitative real-time polymerase chain reaction. Generalized estimating equations were used to evaluate the associations between BTs exposure across gestation and mtDNAcn in cord blood.

RESULTS

In the present study, we observed a positive association between urinary 2-methylthio-benzothiazole (2-MeS-BTH) concentrations in the first trimester and cord blood mtDNAcn, with marginal significance [percent changes (%Δ) = 3.97, 95% confidence interval (CI): -0.05, 8.16, p = 0.05], while urinary 2-amino-benzothiazole concentrations in the third trimester were significantly negatively associated with cord blood mtDNAcn (%Δ = -5.89, 95% CI: -10.32, -1.24). Similar patterns of associations were demonstrated between urinary 1-H-benzotriazole (1-H-BTR) and xylyltriazole concentrations in the third trimester and cord blood mtDNAcn (%Δ = -4.18 to -3.23). In sex-specific analysis, we identified that maternal urinary 1-H-BTR in the first trimester and 2-MeS-BTH in the third trimester were positively associated with cord blood mtDNAcn among male infants but not female (P for interaction = 0.05 for 1-H-BTR, P for interaction = 0.05 for 2-MeS-BTH, respectively).

CONCLUSIONS

We found evidence that prenatal exposure to BTRs and BTHs were associated with cord blood mtDNAcn alternation, and these associations were modified by infant gender. Further investigations are needed to corroborate these findings.

Tyre and road wear particles (TRWP) - A review of generation, properties, emissions, human health risk, ecotoxicity, and fate in the environment

In this paper, the current knowledge on tyre and road wear particles (TRWP) is compiled regarding all environmental and health aspects. TRWP generated on roads during driving processes contribute to airborne non-exhaust emissions and are discussed in connection with the microplastic pollution. The major amount of TRWP consists of coarser heterogenous particles released to road surface, soils and aquatic compartments. The extensive compilation of annual emissions of tyre wear for numerous countries shows per-capita-masses ranging from 0.2 to 5.5 kg/(cap*a). Ecotoxicological studies revealed effects on aquatic organisms, but test concentrations and materials do not reflect environmental conditions. Contribution of tyre wear to PM10 accounts for up to approx. 11 mass %. A recent thorough risk assessment indicates the risk for human health via inhalation to be low, but no information is available on the risk caused by intake via the food chain. Data on degradation is scarce and most studies do not use realistic materials and conditions. The only published degradation study performed under environmental conditions implies a half-life of tyre rubber particles in soils of 16 months. For truck tyres, which mainly contain natural rubber, shorter periods were observed under optimum conditions in laboratory tests. Concentrations of tyre wear compiled from environmental monitoring studies show highly variable concentrations in road runoff, road dust, roadside soils, river sediments and river water, with a general decrease following the transport paths. However, the behaviour of TRWP in freshwater referring to transport, degradation, and sedimentation is still unclarified. Environmental monitoring of TRWP is still hampered by challenges for analytics. Thus, data on environmental concentrations is rare and has mainly exemplary character. Further research is needed with regard to emission factors, development of analytical methods for environmental matrices, long-period monitoring, fate in surface waters and soils, (eco)toxicological impacts and degradation under realistic conditions.

Piezo-activation of peroxymonosulfate for benzothiazole removal in water

Piezoelectricity, as a kind of physical phenomenon, is a coupling between a material's mechanical and electrical behavior. Herein, the local accumulated charges on the surface of piezoelectric material were used to break OO bond of peroxymonosulfate (PMS) to induce its activation for the benzothiazole (BTH) removal. Taking BaTiO₃ as a model piezocatalyst, up to 97 % of BTH was degraded within 30 min in BaTiO₃/PMS/force system, which was respective 40 %, 79 %, 83 % higher than that in BaTiO₃/force piezocatalysis, force/PMS oxidation, and BaTiO₃/PMS adsorption. A significant synergistic effect was observed since the reaction rate constant of BaTiO₃/PMS/force was 3 times higher than the sum of those later three processes. The possible activated mechanism was proposed based on reactive species analysis, DFT calculation and LCMS determination. The stability of the piezocatalyst and the treatment performance for real wastewater were studied to investigate the potential in practical applicability. All the results demonstrated that the BaTiO₃ piezoelectricity can efficiently activate PMS to enhance BTH removal, which is a promising strategy for PMS activation, as well as a valuable insight for the piezoelectrical application in wastewater remediation.

Spatial and seasonal variations of organic corrosion inhibitors in the Pearl River, South China: Contributions of sewage discharge and urban rainfall runoff

While organic corrosion inhibitors are ubiquitous in aquatic environments, knowledge on their occurrence, sources and transport in urban surface water is still scarce. In this study, the spatial and seasonal variations of organic corrosion inhibitors and their potential sources were investigated in the Pearl River Delta (PRD), one of the most highly urbanized watersheds in China. A total of 8 compounds belonging to benzothiazole (BTH) and benzotriazole (BTR) groups respectively, were identified in the Pearl River. In addition, there were clear spatial and temporal differentiations in the concentration profiles. The dry season provided higher concentrations of BTH (213-1082 ng L^-1) and BTR (112-1279 ng L^-1) compared to the wet season (30-574 ng L^-1 for BTH and 23-482 ng L^-1for BTR), indicating a dominant process of dilution. Remarkably higher concentrations and similar composition features of targets were observed in the effluent samples from two sewage treatment plants (STPs). Our study indicated that rainfall runoff from urban traffic roads during wet season may also be an important contributor to the Pearl River water environment. The annual total mass loading of corrosion inhibitors from the main channel of the Pearl River is 53.2 tons and exhibited strong seasonal variation. Effluents discharge from STPs and urban rainfall runoff from traffic roads are main sources of corrosion inhibitors to the Pearl River.

More Than a First Flush: Urban Creek Storm Hydrographs Demonstrate Broad Contaminant Pollutographs

Stormwater runoff clearly impacts water quality and ecological health of urban receiving waters. Subsequent management efforts are often guided by conceptual models of contaminant "first flushes", defined by disproportionate concentrations or mass loads early in the storm hydrograph. However, studies examining the dynamics of contaminant transport and receiving water hydrology have primarily focused on "traditional" stormwater contaminants and point sources, with less evaluation of chemically complex nonpoint pollution sources. Accordingly, we conducted baseflow and storm sampling in Miller Creek, a representative small, urban watershed in the Puget Sound region (WA, USA). We comprehensively characterized organic contaminant profiles and dynamics via targeted quantification of 35 stormwater-derived chemicals, complementary nontarget HRMS analyses, and surrogate chemical metrics of ecological health. For quantified analytes, total daily baseflow loads were 0.8-3.4 g/day and storm event loads were ∼80-320 g/storm (∼48 h interval), with nine contaminants detected during storms at >500 ng/L. Notably, urban creek "pollutographs" were much broader than relatively sharp storm hydrographs and exhibited transport-limited (rather than mass-limited) source dynamics, with immediate water quality degradation during low-intensity precipitation and continued mobilization of contaminant mass across the entire hydrograph. Study outcomes support prioritization of source identification and focused stormwater management efforts to improve water quality and promote ecosystem function in small urban receiving waters.

Ecotoxicology of micronized tire rubber: Past, present and future considerations

Micronized tire rubber has recently come into focus as black particles that are found in microplastic (MP) samples worldwide. These particles have been found in all environmental compartments with the most likely source being the abrasion of car tires on road surfaces. Thus, it is well founded that tires are a source of MPs and that tire abrasion is a primary source of anthropogenic particulates. Currently, the impact of tires has been viewed through the lens of particulate pollution together with MPs, but this is a relatively new direction for this topic. Previously ecotoxicological research into the environmental consequences of tires has primarily been related to the leached chemicals from tire particulates. This paper aims to (i) highlight similarities and differences of micronized rubber particles with the existing suite of polymer contaminants termed as 'microplastics' or 'plastic debris', (ii) survey the existing literature on environmental presence, fate, and interaction of micronized rubber particles with biota, and lastly (iii) present future research needs that require consideration in order to move this research area forward. Existing knowledge gaps that require attention include; determining the environmental presence and fate of micronized rubber within different environmental compartments, understanding the interaction of rubber particles with biota, particularly as potential impacts have so far been attributed solely to the leachate, and evaluating whether standard ecotoxicological protocols need to be adapted for particulate contaminants in general and specifically to suit rubber particulates and leachate.

Toxic compounds in a cutlery microenterprise: A case study

BACKGROUND

The aim of this study was to characterize solid particulate aerosol derived from a cutlery microenterprise and to investigate substances associated with activities performed within the work environment.

OBJECTIVE

Suspended particulate matter (SPM) was collected at different locations in the cutlery workshop and near machines used by workers, using passive sampling devices fitted with polytetrafluoroethylene filters, onto which total particulate material was deposited. The substances present in the SPM were analyzed using gas chromatography-mass spectrometry (GC-MS).

RESULTS

Identification of the substances was performed using the National Institute of Standards (NIST) library and automated mass spectral deconvolution and identification system. (AMDIS) software, considering at least 70% probability. The concentration of total dust, obtained using a gravimetric method, was approximately 1 mg.m-3.

CONCLUSION

The toxic substances found in the SPM included halogenated hydrocarbons (containing chlorine, fluorine, and iodine) and aromatic hydrocarbons. The toxic substances included naphthalene, which is classified as carcinogenic.

Occurrence of and human exposure to benzothiazoles and benzotriazoles in mollusks in the Bohai Sea, China

The Bohai Sea is a semi-enclosed sea in northern China with highly industrialized and urbanized coastal areas and concomitant environmental degradation. Benzothiazoles (BTHs) and benzotriazoles (BTRs) are produced in high volume and widely applied in industrial and consumer products, and little is known about their occurrence and bioaccumulation in coastal marine invertebrates. We determined the concentrations of six BTH and five BTR analogues in mollusks (n = 166) collected from the Bohai Sea between 2006-2014. The total concentrations of BTHs were 229-13800 ng/g dry weight (dw) with a geometric mean of 778 ng/g dw and 7.19-322 ng/g dw for BTRs with a geometric mean of 54.6 ng/g dw. Benzothiazole (BTH) was the dominant compound among the BTHs, accounting for 83.0 % of the total concentration. Among the BTRs, 5,6-dimethyl-1-H-benzotriazole (XTR), 5-methyl-1-H-benzotriazole (5-Me-1-H-BTR), and benzotriazole (1-H-BTR) were major contributors, cumulatively accounting for 78.5 % of the total concentration. Mollusks accumulated elevated levels of BTHs/BTRs regardless of species, suggesting a considerable bioaccumulation potential of BTHs/BTRs in marine ecosystems. Human daily dietary intake of BTHs/BTRs through the consumption of mollusks was estimated based on the concentrations measured. This is the first report on the occurrence and distribution patterns of BTHs/BTRs in a variety of marine invertebrate species from a coastal ecosystem.

Ingestion and Chronic Effects of Car Tire Tread Particles on Freshwater Benthic Macroinvertebrates

Micronized particles released from car tires have been found to contribute substantially to microplastic pollution, triggering the need to evaluate their effects on biota. In the present study, four freshwater benthic macroinvertebrates were exposed for 28 days to tread particles (TP; 10-586 μm) made from used car tires at concentrations of 0, 0.1, 0.3, 1, 3, and 10% sediment dry weight. No adverse effects were found on the survival, growth, and feeding rate of Gammarus pulex and Asellus aquaticus, the survival and growth of Tubifex spp., and the number of worms and growth of Lumbriculus variegatus. A method to quantify TP numbers inside biota was developed and here applied to G. pulex. In bodies and faces of G. pulex exposed to 10% car tire TP, averages of 2.5 and 4 tread particles per organism were found, respectively. Chemical analysis showed that, although car tire TP had a high intrinsic zinc content, only small fractions of the heavy metals present were bioavailable. PAHs in the TP-sediment mixtures also remained below existing toxicity thresholds. This combination of results suggests that real in situ effects of TP and TP-associated contaminants when dispersed in sediments are probably lower than those reported after forced leaching of contaminants from car tire particles.

Screening hundreds of emerging organic pollutants (EOPs) in surface water from the Yangtze River Delta (YRD): Occurrence, distribution, ecological risk

Increased synthetic chemical production and diversification in developing countries caused serious aquatic pollution worldwide with emerging organic pollutants (EOPs) detected in surface water rising health concerns to human and aquatic ecosystem even at low ng/L concentration with long-term exposure. The Yangtze River Delta (YRD) area serves agriculture and industry for people in eastern China. However, the current knowledge on the occurrence and ecological risk of diverse EOPs which are present in the aquatic environment is limited. This study was to investigate the complexity and diversity of EOPs in surface water from 28 sampling sites, which were selected to represent urban, industrial or agriculture areas in the YRD area. In total 484 chemicals were analyze by a target screening approach using liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-HRMS/MS). 181 out of 484 EOPs were detected at least one site in the YRD area, and 44 analytes, mostly industrial chemicals and pesticides, were ubiquitous at all sampling sites. Most EOPs were industrial chemicals with 1H-benzotriazole and organophosphate flame retardants (PFRs) as the chemicals with highest concentrations. For 21 pesticides, mostly herbicides, maximum concentrations of atrazine and isoproturon were above the annual average environmental quality standards of Europe. Amantadine and DEET were the dominant pharmceuticals and personal care products (PPCPs) in the YRD area. Compared to urban areas (mostly in Qinhuai River), chemical profiles from industrial areas were more complex. Industrial activities likely have a strong impact on the composition of chemical mixtures in surface water from the YRD area. ISO E Super, 4-methylbenzylidene camphor and clotrimazole detected in this study are potentially persistent and bioaccumulative chemicals. Furthermore, results of risk assessment showed that hazard quotients of dimethyldioctadecylammonium, didecyldimethylammonium and octocrylene were higher than one and occur frequently, which indicates possibly adverse effects on fish species in the YRD area.

Tire wear particles in the aquatic environment - A review on generation, analysis, occurrence, fate and effects

Tire wear particles (TWP), generated from tire material during use on roads have gained increasing attention as part of organic particulate contaminants, such as microplastic, in aquatic environments. The available information on properties and generation of TWP, analytical techniques to determine TWP, emissions, occurrence and behavior and ecotoxicological effects of TWP are reviewed with a focus on surface water as a potential receptor. TWP emissions are traffic related and contribute 5-30% to non-exhaust emissions from traffic. The mass of TWP generated is estimated at 1,327,000 t/a for the European Union, 1,120,000 t/a for the United States and 133,000 t/a for Germany. For Germany, this is equivalent to four times the amount of pesticides used. The mass of TWP ultimately entering the aquatic environment strongly depends on the extent of collection and treatment of road runoff, which is highly variable. For the German highways it is estimated that up to 11,000 t/a of TWP reach surface waters. Data on TWP concentrations in the environment, including surface waters are fragmentary, which is also due to the lack of suitable analytical methods for their determination. Information on TWP properties such as density and size distribution are missing; this hampers assessing the fate of TWP in the aquatic environment. Effects in the aquatic environment may stem from TWP itself or from compounds released from TWP. It is concluded that reliable knowledge on transport mechanism to surface waters, concentrations in surface waters and sediments, effects of aging, environmental half-lives of TWP as well as effects on aquatic organisms are missing. These aspects need to be addressed to allow for the assessment of risk of TWP in an aquatic environment.

Benzothiazole heterogeneous photodegradation in nano α-Fe2O3/oxalate system under UV light irradiation

The photodegradation of benzothiazole (BTH) in wastewater with the coexistence of iron oxides and oxalic acid under UV light irradiation was investigated. Results revealed that an effective heterogeneous photo-Fenton-like system could be set up for BTH abatement in wastewater under UV irradiation without additional H₂O₂, and 88.1% BTH was removed with the addition of 2.0 mmol l^-1 oxalic acid and 0.2 g l^-1 α-Fe₂O₃ using a 500 W high-pressure mercury lamp (365 nm). The degradation of BTH in the photo-Fenton-like system followed the first-order kinetic model. The photoproduction of hydroxyl radicals (·OH) in different systems was determined by high-performance liquid chromatography. Identification of transformation products by using liquid chromatography coupled with high resolution tandem mass spectrometry provided information about six transformation products formed during the photodegradation of BTH. Further insight was obtained by monitoring concentrations of the sulfate ion (SO42-) and nitrate ion (NO3-) , which demonstrated that the intermediate products of BTH could be decomposed ultimately. Based on the results, the potential photodegradation pathway of BTH was also proposed.

A Review of Environmental Occurrence, Fate, Exposure, and Toxicity of Benzothiazoles

Benzothiazole and its derivatives (BTs) are high production volume chemicals that have been used for several decades in a large number of industrial and consumer products, including vulcanization accelerators, corrosion inhibitors, fungicides, herbicides, algicides, and ultraviolet (UV) light stabilizers. Several benzothiazole derivatives are used commercially, and widespread use of these chemicals has led to ubiquitous occurrence in diverse environmental compartments. BTs have been reported to be dermal sensitizers, respiratory tract irritants, endocrine disruptors, carcinogens, and genotoxicants. This article reviews occurrence and fate of a select group of BTs in the environment, as well as human exposure and toxicity. BTs have frequently been found in various environmental matrices at concentrations ranging from sub-ng/L (surface water) to several tens of μg/g (indoor dust). The use of BTs in a number of consumer products, especially in rubber products, has resulted in widespread human exposure. BTs undergo chemical, biological, and photolytic degradation in the environment, creating several transformation products. Of these, 2-thiocyanomethylthio-benzothiazole (2-SCNMeS-BTH) has been shown to be the most toxic. Epidemiological studies have shown excess risks of cancers, including bladder cancer, lung cancer, and leukemia, among rubber factory workers, particularly those exposed to 2-mercapto-benzothiazole (2-SH-BTH). Human exposure to BTs continues to be a concern.