Persistence, temporal and spatial profiles of ultraviolet absorbents and phenolic personal care products in riverine and estuarine sediment of the Pearl River catchment, China

Parabens and triclosan in red swamp crayfish (Procambarus clarkii) from China: Concentrations, tissue distribution and related human dietary intake risk

Parabens (PBs) and triclosan (TCS) are commonly found in pharmaceuticals and personal care products (PPCPs). As a result, they have been extensively found in the environment, particularly in aquaculture operations. Red swamp crayfish (Procambarus clarkii) consumption has significantly risen in China. Nevertheless, the levels of PBs and TCS in this species and the associated risk to human dietary intake remain undisclosed. This study assessed the amounts of five PBs, i.e., methyl-paraben (MeP), ethyl-paraben (EtP), propyl-paraben (PrP), butyl-paraben (BuP) and benzyl-paraben (BzP), as well as TCS in crayfish taken from five provinces of the middle-lower Yangtze River. MeP, PrP and TCS showed the highest detection rates (hepatopancreas: 46-86 %; muscle: 63-77 %) since they are commonly used in PPCPs. Significantly higher levels of ∑5PBs (median: 3.69 ng/g) and TCS (median: 7.27 ng/g) were significantly found in the hepatopancreas compared to the muscle (median: 0.39 ng/g for ∑5PBs and 0.16 ng/g for TCS) (p < 0.05), indicating bioaccumulation of these chemicals in the hepatopancreas. The estimated daily intake values of ∑5PBs and TCS calculated from the median concentrations of crayfish were 6.44-7.94 ng/kg bw/day and 11.4-14.0 ng/kg bw/day, respectively. Although no health risk was predicted from consuming crayfish (HQ <1), consumption of the hepatopancreas is not recommended.

Benzotriazole ultraviolet absorbents in surface waters and sediments of the Bohai Sea and North Yellow Sea: Spatial trends and influencing factors

Benzotriazole ultraviolet absorbents (BUAs) of emerging concern were recently monitored in seawater and sediments from the Bohai Sea (BS) and North Yellow Sea (NYS), which are impacted by human activities, to elucidate their regional occurrence patterns, phase distributions, and contamination profiles. Although environmental variables such as sedimentary organic carbon, particle size, and salinity, as well as hydrological conditions, affected the environmental occurrence of BUAs in the BS and NYS, the source dependence of BUA distributions associated with urban impacts and riverine inputs was highlighted. Substantial spatial variability in the composition patterns and contamination profiles of BUAs identified through correlation and principal component analyses were likely caused by region-specific sources and characteristics. The distribution of target BUAs between the sediment and seawater phases showed no dependence on the octanol-water partition coefficient (KOW) but exhibited marked spatial variations. The diversity of BUA sorption behaviors was further explained by the total organic carbon (TOC)-normalized distribution coefficient (KTOC). Classic logKTOC-logKOW linear relationships accurately predicted the phase distributions of UV-326, UV-328, and UV-234, but deviations were found for lighter and heavier BUAs, possibly due to the influences of physical disturbance and microparticle binding.

Leaching potentials of microplastic fibers and UV stabilizers from coastal-littered face masks

Synthetic fibrous textiles are ubiquitous plastic commodities in everyday existence. Nevertheless, there exists a dearth of understanding regarding their environmental occurrence and the releasing capacities of associated additives. In this study, ten additives were determined in twenty-eight kinds of daily used plastic products including face masks, synthetic clothing, and food containers. Our results revealed that a typical kind of fibrous plastic, face masks, contained a greater variety of additives with UV stabilizers in particular, when compared to other plastic commodities. The above phenomena triggered our field investigation for the occurrence and release potentials of face mask fibers and the co-existing UV stabilizers into the environment. We further collected 114 disposed masks from coastal areas and analyzed their UV stabilizer concentrations. Results showed that the abundance of littered face masks ranged from 40-1846 items/km2 along the Yangtze Estuary, China; and UV stabilizers were of 0.3 ± 0.7 ng/g and 0.7 ± 1.7 ng/g in main bodies and ear ropes, respectively. The UV stabilizer concentrations in the field collected masks were only ∼7 % of their new counterparts, implying their potential leaching after disposal. By simulating the weathering scenario, we predict that a substantial amount of microplastics, with 1.1 × 1010 polypropylene fibers and 3.7 × 1010 polyester fibers, are probably be released daily into the coastal environment after face masks disposal; whereas the accompanied leaching amount of UV stabilizers was relatively modest under the current scenario.

Discovery of novel benzotriazole ultraviolet stabilizers in surface water

The comprehensive understanding of the occurrence of benzotriazole UV stabilizers (BZT-UVs) in environmental surface water is imperative due to their widespread application and potential aquatic toxicity. We conducted an analysis of 13 traditional BZT-UVs in surface water samples collected from Taihu Lake (TL, n = 23) and Qiantang River (QR, n = 22) in China. The results revealed that 5‑chloro-2-(3,5-di-tertbutyl-2-hydroxyphenyl)-benzotriazole (UV-327) was consistently the predominant BZT-UV in water samples from TL (mean 16 ng/L; detection frequency 96 %) and QR (14 ng/L; 91 %). Furthermore, we developed a characteristic fragment ion-based strategy to screen and identify unknown BZT-UVs in collected surface water, utilizing a high-resolution mass spectrometer. A total of seven novel BZT-UVs were discovered in water samples, and their chemical structures were proposed. Four of these novel BZT-UVs were further confirmed with standards provided by industrial manufacturers. Semi-quantitative analysis revealed that among discovered novel BZT-UVs, 2-(2‑hydroxy-3‑tert‑butyl‑5-methylphenyl)-benzotriazole was consistently the predominant novel BZT-UV in TL (mean 4.1 ng/L, detection frequency 70 %) and QR (2.8 ng/L, 77 %) water. In TL water, the second predominant novel BZT-UV was 2-(3-allyl-2‑hydroxy-5-methylphenyl)-2H-benzotriazole (mean 3.9 ng/L, Collapse

Key Words

• Benzotriazole UV stabilizers
• Non-target analysis
• Novel BZT-UVs
• Surface water
• UV-327

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MESH Headings

• Triazoles/chemistry
• Water Pollutants, Chemical/chemistry
• China
• Lakes/chemistry
• Ultraviolet Rays
• Rivers/chemistry
• Environmental Monitoring

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Grants Collapse

Affiliation(s)

Yuanchen Chen Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Ruyue Guo Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Kaizhen Liao Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Wenfei Yu Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Pengfei Wu Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, PR China
Hangbiao Jin Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China.

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Estuarine hydrodynamic processes driving the molecular changes of terrestrial dissolved organic nitrogen: From mixing to biological modification

Estuaries receive substantial amounts of terrestrial dissolved organic nitrogen (tDON), which will be transported from the freshwater to the oceanic terminus through vigorous exchange processes. However, the intricate migration and transformation dynamics of tDON during this transportation, particularly at a molecular level, remain constrained. To address this knowledge gap, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used for the analysis of DON molecular composition in the Pearl River Estuary (PRE), a river-dominated estuarine system influenced by intensified anthropogenic activities in southern China. The results showed a pronounced spatial-temporal variation in DON concentration in the study area. At the molecular level, tDON exhibited reduced unsaturation and aromaticity, coupled with an elevated abundance of DON compounds containing one‑nitrogen atom (1 N-DON, 53.17 %) and compounds containing carbon, hydrogen, oxygen, nitrogen, and sulfur (CHONS) (27.46 %). It was evident that lignin was depleted while more oxygenated tannin compounds were generated in the freshwater-seawater mixing zone. This transformation is attributed to heightened biological activities, likely influenced by the priming effect of terrestrial nutrient inputs. In summer, the prevailing plume combined with biological activities in the strong mixing area and outer estuary increased the abundance of 3 N-DON molecules and a concurrent rise in the abundance of DON compounds containing only carbon, hydrogen, oxygen, and nitrogen (CHON), DON compounds containing carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus (CHONSP), and CHONS. This trend also underscores the expanding role of marine plankton and microbes in the utilization of DON compounds containing carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP). These findings provide details of tDON transformation processes at the molecular level in a river-dominated estuary and underline the estuarine hydrodynamics involved in transporting and altering DON within the estuary.

Comparison of benzotriazole ultraviolet stabilizers (BUVs) removal from wastewater after subsequent stages of sequencing batch reactor (SBR) treatment process

The research focused on benzotriazole ultraviolet stabilizers (BUVs) which are commonly used compounds despite being found dangerous, e.g. promoting breast cancer cell proliferation, damaging vital organs such as hearts, brains livers and kidneys. The aim of the study was to analyse the efficiency and removal rate of BUVs from wastewater depending on the quantity of tested compounds and SBR anaerobic-aerobic conditions. The study was conducted in sequencing batch reactors (SBRs - 17 L) with real flocculent activated sludge (8 L) and model wastewater (5 L) containing UV-326, UV-327, UV-328, UV-329 and UV-P from 50 to 600 μg∙L-1. The SBR were operated in 390 cycles of 7 h and 10 min over 130 days. The similarity of the technological parameters of the treatment process to those used in a real wastewater treatment plant was maintained. Efficiency removal of individual BUVs was strictly dependent on the dose of compounds introduced into wastewater and ranged from 68.2 to 97 %. Removal of UV-329 occurred with lowest efficiency (from 68.2 to 85.2 %) while UV-326 was most efficiently removed from the wastewater (from 94.1 to 97 %). UV-329 was removed from wastewater with the lowest (0.0968-0.9524 μg∙L-1∙min-1) average removal rate while UV-327 with the highest (0.16-1.3357 μg∙L-1∙min-1), irrespective of BUVs dose in the influent. Secondary release of BUVs into the wastewater occurred in SBR during the settling phase and was dependent on the type and concentration of the BUVs in the raw wastewater. This occurrence was noted for UV-326 ≥ 100; UV-327 = 600; UV-328 ≥ 200; UV-329 ≥ 50 and UV-P ≥ 100 μg∙L-1. The settling phase needs to be shortened to the required minimum. This is an important conclusion for WWTPs in regards to SBR cycle duration and technological parameters of the treatment process.

Occurrence, distribution, and ecological risks of polyhalogenated carbazoles in sediments from Daya Bay and Pearl River Estuary, China

Polyhalogenated carbazoles (PHCZs) are a group of emerging organic pollutants attracting increasing concern. In this study, 32 sediment samples were collected from the Pearl River Estuary (PRE) and adjacent Daya Bay (DYB) in China and were investigated for the occurrence and distribution of PHCZs. Total concentration of sedimentary PHCZs (∑PHCZs) ranged from 0.79 to 3.08 ng/g in PRE and 0.89 to 1.95 ng/g in DYB, both containing 3,6-dichlorocarbazole as the main component. Higher concentrations of ∑PHCZs were found in the rivers-mouth and inner part of the PRE indicating their main origins from anthropogenic activities. Notably, concentrations of brominated carbazoles (BCZs) gradually increased offshore, which suggests the potential bio-transformation of BCZs under a saline environment. The toxic equivalent of PHCZs was estimated at 0.13-0.34 pg TEQ/g suggesting limited dioxin-like effects on local organisms.

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

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

Emerging contaminants and their potential impacts on estuarine ecosystems: Are we aware of it?

Emerging contaminants (ECs) are becoming more prevalent in estuaries and constitute a danger to both human health and ecosystems. These pollutants can infiltrate the ecosystem and spread throughout the food chain. Because of the diversified sources and extensive human activities, estuaries are particularly susceptible to increased pollution levels. A thorough review on recent ECs (platinum group elements, pharmaceuticals and personal care products, pesticides, siloxanes, liquid crystal monomers, cationic surfactant, antibiotic resistance genes, and microplastics) in estuaries, including their incidence, detection levels, and toxic effects, was performed. The inclusion of studies from different regions highlights the global nature of this issue, with each location having its unique set of contaminants. The diverse range of contaminants detected in estuary samples worldwide underscores the intricacy of ECs. A significant drawback is the scarcity of research on the toxic mechanisms of ECs on estuarine organisms, the prospect of unidentified ECs, warrant research scopes.

Endocrine-disrupting chemicals in Vietnamese marine fish: Occurrence, distribution, and risk assessment

The release of endocrine-disrupting chemicals (EDCs) into the aquatic environment, specifically the oceans, is increasing, leading to adverse effects on the marine ecosystem. Using optimized QuEChERS extraction methods, the study created the first contamination profiles of 44 EDCs, including organic ultraviolet compounds, pharmaceutically active compounds, hormones, and phthalate esters, in 114 fish muscle samples from five species collected along the Vietnamese coast. The study found that largehead hairtail exhibited the highest total EDCs at 208.3 ng g-1 lipid weight (lw), while Indian catfish displayed the lowest concentration at 105.5 ng g-1 lw. Besides, the study observed notable variations in the total EDCs across distinct fish species. This study hypothesized that the marine economic characteristics of each research location have a significant role in shaping the pollution profile of EDCs found in fish specimens taken from the corresponding area. As a result, a notable disparity in the composition of organic ultraviolet compounds has been observed among the three regions of North, Central, and South Vietnam (Mann-Whitney U test, p < 0.05). Despite these findings, EDC-contaminated fish did not pose any health risks to Vietnam's coastal population.

Ecological risk assessment of 50 emerging contaminants in surface water of the Greater Bay Area, China

Ecological risk assessment of emerging contaminants (ECs) is an international research hotspot and is also the focus of China's "14th Five-Year Plan". The Greater Bay Area (GBA) is one of the four major bay areas in the world and the most dynamic region in China. However, there are few studies on the risk assessment of ECs in the GBA, and there needs to be a systematic and comprehensive assessment of the ecological risk of ECs. We selectively collected environmental concentration and toxicity data reported in the literature before 2022 for 50 representative ECs. We use risk quotient (RQ), semi-probability, Margin of Safety (MOS), and joint Probability curve (JPC) methods for multiple-level risk assessment. The RQ results showed that there were primary ecological risks in 20 ECs. Nine ECs were screened by the semi-probability, MOS, and JPC methods. The total risk probability of nonylphenol (NP) to the GBA was 12.11 %, and the risk to the aquatic ecological environment was the highest, followed by α-endosulfan (α-END) and erythromycin (ERY). At the same time, a comprehensive assessment method was adopted to screen the list of medium and high-risk priority pollutants in the GBA. According to the comprehensive evaluation results, although the risk is low, perfluorooctanoic acid (PFOA) still deserves widespread attention. The results showed that NP, α-END, ERY, and PFOA may be the most concerned ECs in the GBA. This research fills the gap on the ECs ecological risk assessment of the GBA and can provide a theoretical reference for managers in the follow-up of ECs regulatory governance.

Estimation of the riverine input of organic ultraviolet filters (OUVFs) from the Pearl River Estuary to the South China Sea during the early Covid-19 pandemic

Organic ultraviolet filters (OUVFs) are functional ingredients used in cosmetics to protect skin from the harmful effects of ultraviolet (UV) radiation. This study presents recent findings on the distribution of OUVFs in the Pearl River Estuary (PRE), located in southern China. This investigation was conducted during the early stages of the Covid-19 pandemic when the stay-at-home policy was implemented. Analysis revealed the presence of OUVFs in both the surface and bottom water samples collected from eight major outlets of the Pearl River. The OUVFs were detected in both the dissolved phase and suspended particulate matter, with a total concentration ranging from 7.19 ± 6.54 to 20.5 ± 9.62 ng/L. Notably, OUVFs' concentrations in the study period were significantly lower compared to those reported before the pandemic. This implies that effective reduction of OUVF emissions can be achieved through usage reduction combined with the management of direct discharge and appropriate treatment by urban wastewater treatment facilities. During the study period, the annual release of OUVFs was approximately 12.6 kg/1000 people/year, with the greatest contribution from the Hu Men outlet. Consequently, it is imperative to consider the potential ecological risks associated with the release of OUVFs from the PRE into the marine environment, particularly with the potential for an accompanying rebound in risk upon the lifting of restrictions on outdoor activities in the post Covid-19 time.

Organic UV absorbents in the deepwater redfish (Sebastes mentella) from the St. Lawrence Estuary and Gulf: Distribution and human health risk assessment

UV absorbents (UVAs), such as organic UV filters (UVFs) and benzotriazole UV stabilizers (BZT-UVs), are used in a wide range of consumer and industrial products and they are contaminants of emerging concern in the environment. However, their occurrence and fate in the deep-sea environments are inadequately understood. This study investigated the occurrence and distribution of five UVFs and ten BZT-UVs in the muscle (n = 127) of 2019-collected deepwater redfish (Sebastes mentella) from the St. Lawrence Estuary and Gulf (SLEG) (Canada) to better understand the accumulation of these contaminants in deep-sea fish. Small redfish (<30 cm) tended to have higher concentrations of UVAs in the muscle than that of larger specimens (>30 cm). The UVF 2-hydroxy-4-methoxybenzophenone (BP3) was the most frequently detected (present in 34 % of all samples) target UVA, with concentrations as high as 413 ng/g (dry weight). According to the δ15N and δ13C data, pelagic-eating redfish, and individuals with lower trophic levels had higher lipid content and accumulated more BP3 in their muscles. Four BZT-UVs were detected in redfish muscle, but the detection frequency was lower than 30 %. The estimated hazard quotient for these contaminants was <2.3 × 10-2 for general Canadian populations, indicating that they are unlikely to pose health risks to humans through redfish consumption. Factors influencing UVAs bioaccumulation in redfish, as well as the effects UVAs may have on deep-sea species, should be researched further.

Organic ultraviolet absorbents in soils and typical plants from an industrial metropolis in China: Concentrations, profiles and environmental implications

There is accumulating evidence of the toxicity of organic ultraviolet absorbers (OUVAs); however, limited information is available regarding the presence of OUVAs in terrestrial environments and organisms. Therefore, this study was conducted to investigate the occurrence of 11 OUVAs in soils and typical plant species from an industrial metropolis in China. Total OUVA concentrations in soils ranged from 1.30 to 80.3 ng g-1 DW. Based on comparison with previously reported data, OUVA contamination in soil was not severe. Benzophenone and octocrylene were the dominant OUVAs in soils, with median contributions to total concentrations of 25% and 15%, respectively. Source assessment revealed that the observed OUVA contamination primarily originated from industrial activities and the use of personal care products. The concentration of 11 OUVAs in plants ranged from 159 to 4470 ng g-1 DW, at high levels. Our findings imply that great attention should be given to the presence of these chemicals in plants because of the risk they could pose as well as the potential for biomagnification as plants are eaten by insects and birds. Our results also indicate the necessity to further study the geochemical behavior of these chemicals in urban ecosystems in order to better manage the harmfulness to terrestrial ecological health caused by their exposure through the food chains.

Provenance analyses of silted sediments in Shenzhen Bay: Insights based on rare earth elements and stable isotopes

Shenzhen Bay (SZB) in southern China is a typical eutrophic area, with internal pollution from its sediments representing an important nutrient source. However, the transport paths and sources of sediments in SZB remain unclear, making it difficult to analyze the nutritional budget and propose effective sediment management strategies. To address this, we linked a sediment fingerprinting technique to a Bayesian mixing model (MixSIAR) and conducted provenance analyses. We collected particle samples from SZB sediment and surrounding areas, including the Shenzhen River (SZR), Pearl River Estuary (PRE), and the northern South China Sea (SCS). Two groups of natural tracers were measured to trace different phases of sediments: (1) C and N parameters for the fates of the organic phase of sediments, and (2) rare earth element (REE) patterns for the provenance of mineral fragments. The results showed that the concentrations of total organic C and total N were 0.89-1.44 % and 0.05-0.13 %, respectively. MixSIAR suggested that fluvial inputs from SZR and PRE contributed 46.6 % and 30.3 % of organic matter, respectively. The organic matter in the PRE mainly originated from sewage and the upper reaches of the Pearl River. The concentration range of REEs in SZB sediments was 153.12-480.09 mg/kg with clear enrichment for light REE. MixSIAR results showed that the mineral fragments mainly originated from the outer bay (SCS and PRE, which contributed 57.2 % and 32.7 %, respectively). These results indicate that organic pollution follows a different path from the inorganic base, which is mainly related to anthropogenic input from land. This study highlights that complex sediment transport processes and pollution intrusions from the Pearl River are the issues that must be considered for eutrophication restoration in SZB.

New insight into the removal process of benzotriazole UV stabilizers by UV/H2O2: Integrating quantum chemical calculation with CFD simulation

Benzotriazole UV stabilizers (BT-UVs) are important UV absorbers. As high-production chemicals and potential hazards, their ubiquitous presence in aquatic environments is of greatly pressing concern. Herein, the removal of six typical BT-UVs by UV/H2O2 was comprehensively investigated by quantum chemistry calculation integrated with CFD simulation. Utilizing such a micro and macro incorporated model in treating contaminants is the first report. From the micro-view, degradation mechanisms of BT-UVs by •OH oxidation were determined, and corresponding rate constants were obtained with values of 109∼1010 M-1s-1. In a macroscopic aspect, combining the established kinetic model and CFD simulation, the effects of UV lamp power (P), volumetric flow rate (Qv), and H2O2 dosage ([H2O2]0) on removal yields of BT-UVs were expounded, increasing P or [H2O2]0 or decreasing Qv are effective in improving removal yields of BT-UVs, but the enhancement was abated when P or [H2O2]0 increased to a certain level. When [H2O2]0 is 5 mg/L and Qv is decreased from 0.1 to 0.05 m3/h, the removal yields of BT-UVs could achieve more than 95% (P = 150 W) and 99% (P = 250 W), respectively. This work provides a new interdisciplinary insight for investigating organic contaminant removal in potential industrial applications of UV/H2O2 systems.

Embryonic Exposure to UV-328 Impairs the Cell Cycle in Zebrafish (Danio rerio) by Inhibiting the p38 MAPK/p53/Gadd45a Signaling Pathway

The benzotriazole UV stabilizer UV-328 is well known for its potent antioxidative properties; however, there are concerns about how it may affect signaling nodes and lead to negative consequences. This study identified the key signaling cascades involved in oxidative stress in zebrafish (Danio rerio) larvae and evaluated the cell cycle arrests and associated developmental alternations. Exposure to UV-328 at 0.25, 0.50, 1.00, 2.00, and 4.00 μg/L downregulated gene expression associated with oxidative stress (cat, gpx, gst, and sod) and apoptosis (caspase-3, caspase-6, caspase-8, and caspase-9) at 3 days postfertilization (dpf). The transcriptome aberration in zebrafish with disrupted p38 mitogen-activated protein kinase (MAPK) cascades was validated based on decreased mRNA expressions of p38 MAPK (0.36-fold), p53 (0.33-fold), and growth arrest and DNA damage-inducible protein 45 α (Gadd45a) (0.52-fold) after a 3- and 14-day exposure alongside a correspondingly decreased protein expression. The percentage of cells in the Gap 1 (G1) phase increased from 69.60% to a maximum of 77.07% (p < 0.05) in the 3 dpf embryos. UV-328 inhibited the p38 MAPK/p53/Gadd45a regulatory circuit but promoted G1 phase cell cycle arrest, abnormally accelerating the embryo hatching and heart rate. This study provided mechanistic insights that enrich the risk profiles of UV-328.

Fatty acids as bioindicators of organohalogen exposure in marine fish from a highly polluted estuary: First insight into small-scale regional differences

Increasing evidence has revealed the lipid-disrupting effects of organic contaminants on aquatic organisms, raising attention about the efficacy of fatty acids (FAs) as bioindicator of contaminant exposure on marine organisms. Here, we investigated the concentrations of 55 organohalogen contaminants (OHCs), 35 FAs, and their correlations in 15 marine fish species (n = 274) from the estuary outlets of the west four region (WFR) and Lingdingyang (LDY) waters in the Pearl River Estuary (PRE), respectively. Despite the similar OHC profiles, significantly higher concentrations of ∑₅₅OHCs were detected in fish from the LDY than those in the WFR. However, FAs in the LDY fish generally contained lower proportions of polyunsaturated fatty acids than in the WFR fish. A total of 148 and 221 significant correlations between OHCs and FAs were observed in fish samples from the LDY and WFR, respectively, supporting that FAs could be efficient bioindicators of OHC stress in marine fish. However, the low overlaps (14/369) of OHC-FA correlations in fish from the two regions suggested that the bioindicators of OHCs might have spatial heterogeneity. Our results highlighted that FAs likely act as potential bioindicators of OHCs in marine fish, while the regional-specific characteristic of the bioindicators should be considered.

Cloning and rational modification of a cold-adapted esterase for phthalate esters and parabens degradation

Phthalate esters (PAEs) and parabens are environmental pollutants that can be toxic to human health. Herein, a cold-adapted esterase from the Mao-tofu metagenome named Est1260 was screened for its PAE-hydrolyzing potential in cold temperatures. The results showed that purified Est1260 could degrade a variety of PAEs and parabens at temperatures as low as 0 °C. After careful analysis of the structural information and molecular docking, site-saturation mutation was conducted at the identified hotspots. Protein expression of variant A1B6 doubled, and its thermal stability significantly improved (24 times) without sacrificing activity at low temperatures. In addition, Est1260 and its variants were activated by NaCl and demonstrated resistance to high concentrations of saline (up to 5 M), making it a potential biocatalyst for bioremediation of PAE and paraben-polluted environments.

The diabetogenic effects of pesticides: Evidence based on epidemiological and toxicological studies

While the use of pesticides has improved grain productivity and controlled vector-borne diseases, the widespread use of pesticides has resulted in ubiquitous environmental residues that pose health risks to humans. A number of studies have linked pesticide exposure to diabetes and glucose dyshomeostasis. This article reviews the occurrence of pesticides in the environment and human exposure, the associations between pesticide exposures and diabetes based on epidemiological investigations, as well as the diabetogenic effects of pesticides based on the data from in vivo and in vitro studies. The potential mechanisms by which pesticides disrupt glucose homeostasis include induction of lipotoxicity, oxidative stress, inflammation, acetylcholine accumulation, and gut microbiota dysbiosis. The gaps between laboratory toxicology research and epidemiological studies lead to an urgent research need on the diabetogenic effects of herbicides and current-use insecticides, low-dose pesticide exposure research, the diabetogenic effects of pesticides in children, and assessment of toxicity and risks of combined exposure to multiple pesticides with other chemicals.

Spatiotemporal trends of ultraviolet absorbents in oysters from the Pearl River Estuary, south China during 2015-2020

Ultraviolet absorbents (UVAs) are widely used in various industrial materials, pharmaceuticals, and personal care products, resulting in their frequent occurrences in sediment, water, and biota. However, our understanding of the spatiotemporal characteristics and long-term contamination status of UVAs is still limited. Here, a 6-year biomonitoring study with oysters during wet and dry seasons was conducted to examine the annual, seasonal, and spatial characteristics of UVAs in the Pearl River Estuary (PRE), China. The concentrations of Σ₆UVA ranged from 9.1 to 119 (geometric mean ± standard deviation: 31 ± 22) ng/g dry wt. and peaked in 2018. Significant spatiotemporal variations in UVA contamination were observed. The concentrations of UVAs in oysters during the wet season were higher than the dry season, and concentrations in the more industrialized eastern coast were higher than the western coast (p < 0.05). Environmental factors, including precipitation, temperature, and salinity in water significantly impacted the UVA bioaccumulation in the oysters. The present study highlights that long-term biomonitoring with oysters provided valuable insight in the magnitude and seasonal variation of UVAs in this highly dynamic estuary.

Trophodynamic of endocrine disrupting compounds in the aquatic food webs: Association with hydrophobicity and biota metabolic rate

Increasing concentration of endocrine disrupting compounds (EDCs) are released into the aquatic environment, resulting in irreversible effects on the endocrine and reproductive systems of biota. How the liver enzymes affect metabolic rate of these compounds and thus their structure-related trophic transfer in aquatic food webs remains largely unknown. In this study, the concentrations of seven common EDCs were measured in 15 species of fish, 7 invertebrate species and plankton collected from Liuxi River to Pearl River, South China. The mean ΣEDC concentrations generally were found to increase as follows: plankton (29.59 ng g^-1 dw) < invertebrate species (50.69 ng g^-1 dw) < fish (122.56 ng g^-1 dw), with 4-nonylphenol (4-NP) and bisphenol S (BPS) as the predominant components. Trophic magnification factors (TMFs) values were >1.0 ranged from 1.30 (BPS) to 4.07 (4-NP), indicating trophic magnification potential. Measurement of metabolism and activities of microsomal CYP450 enzymes were performed in the fish liver microsomes of Hypophthalmichthys molitrix ([TL] = 2.27), Cirrhinus mrigala (TL = 3.87) and Odontamblyopus rubicundus (TL = 4.73). TMFs were significantly negatively correlated with the obtained in vitro biotransformation clearance rates (CL _{in vitro}) of EDCs and CYP450 enzymes activities. A multiple linear regression model indicated that biotransformation clearance is a more powerful predictor for TMFs than the hydrophobicity (Kow) to drive changes in the studied aquatic food web trophodynamics.

Occurrence, bioaccumulation and ecological risk of organic ultraviolet absorbers in multiple coastal and offshore coral communities of the South China Sea

The occurrence of organic ultraviolet absorbers (OUVAs) in coral reef regions has aroused widespread concern. This study focused on the occurrence, distribution, bioaccumulation and ecological risk of ten OUVAs in both coastal and offshore coral reef regions in the South China Sea. While the Σ₁₀OUVAs was 85 % lower in the offshore seawater (15.1 ng/L) than in the coastal seawater (102.1 ng/L), the Σ₁₀OUVAs was 21 % lower in the offshore corals (1.82 μg/g dry weight (dw)) than in the coastal corals (2.31 μg/g dw). This difference was speculated to relate to the high intensity of human activities in the coastal regions. Moreover, the offshore corals showed higher bioaccumulative capability toward OUVAs (log bioaccumulation factors (BAFs): 1.22-5.07) than the coastal corals (log BAFs: 0.17-4.38), which was presumably the influence of varied physiological status under different environmental conditions. The results of the ecological risk assessment showed that BP-3 resulted in 73 % of coastal corals and 20 % of offshore corals at a risk of bleaching. Therefore, the usage and discharge of BP-3 should be managed and controlled by the countries adjacent to the South China Sea for the protection of coral reefs.

Development and Validation of a DLLME-GC-MS-MS Method for the Determination of Benzotriazole UV Stabilizer UV-327 and Its Metabolites in Human Blood

2-(5-Chloro-benzotriazol-2-yl)-4,6-di-(tert-butyl)phenol (UV-327) is used as an ultraviolet (UV) absorber in plastic materials and coatings. To investigate its metabolism and to assess human exposure, analytical methods are necessary for the determination of UV-327 and its metabolites in human biological specimens. The method thus presented targets the determination of UV-327 and several of its predicted metabolites in blood using protein precipitation, dispersive liquid-liquid microextraction (DLLME) and derivatization. The trimethylsilylated analytes and internal standards are separated by gas chromatography and analyzed with tandem mass spectrometry. The DLLME procedure was optimized with respect to the type and volume of disperser and extraction solvents, the pH value of the sample solution and the addition of salt. During method development, an effective ex vivo lactone/hydroxyl carboxylic acid interconversion was observed for two metabolites, each containing a carboxyl group adjacent to the phenolic hydroxyl group. The analytes resulting from interconversion enabled a more sensitive and reliable determination of the metabolites compared to their native structures. Method validation revealed limits of detection between 0.02 and 0.36 µg/L. The mean relative recovery rates ranged from 91% to 118%. Precision and repeatability were demonstrated by relative standard deviations in the range of 0.6-14.2% and 1.1-13.7%, respectively. The presently described procedure enables the sensitive and robust analysis of UV-327 and its metabolites in human blood and allows the elucidation of the human UV-327 metabolism as well as the assessment of exposure in potentially exposed individuals.

Can short-term data accurately model long-term environmental exposures? Investigating the multigenerational adaptation potential of Daphnia magna to environmental concentrations of organic ultraviolet filters

Organic ultraviolet filters (UVFs) are contaminants of concern, ubiquitously found in many aquatic environments due to their use in personal care products to protect against ultraviolet radiation. Research regarding the toxicity of UVFs such as avobenzone, octocrylene and oxybenzone indicate that these chemicals may pose a threat to invertebrate species; however, minimal long-term studies have been conducted to determine how these UVFs may affect continuously exposed populations. The present study modeled the effects of a 5-generation exposure of Daphnia magna to these UVFs at environmental concentrations. Avobenzone and octocrylene resulted in minor, transient decreases in reproduction and wet mass. Oxybenzone exposure resulted in > 40% mortality, 46% decreased reproduction, and 4-fold greater reproductive failure over the F0 and F1 generations; however, normal function was largely regained by the F2 generation. These results indicate that Daphnia are able to acclimate over long-term exposures to concentrations of 6.59 μg/L avobenzone, ∼0.6 μg/L octocrylene or 16.5 μg/L oxybenzone. This suggests that short-term studies indicating high toxicity may not accurately represent long-term outcomes in wild populations, adding additional complexity to risk assessment practices at a time when many regions are considering or implementing UVF bans in order to protect these most sensitive invertebrate species.

Response and recovery mechanisms of river microorganisms to gradient concentrations of estrogen

As an important ecological system on the earth, rivers have been influenced by the rapid development of urbanization, industrialization, and anthropogenic activities. Increasingly more emerging contaminants, such as estrogens, are discharged into the river environment. In this study, we conducted river water microcosmic experiments using in situ water to investigate the response mechanisms of microbial community when exposed to different concentrations of target estrogen (estrone, E1). Results showed that both exposure time and concentrations shaped the diversity of microbial community when exposed to E1. Deterministic process played a vital role in influencing microbial community over the entire sampling period. The influence of E1 on microbial community could last for a longer time even after the E1 has been degraded. The microbial community structure could not be restored to the undisturbed state by E1, even if disturbed by low concentrations of E1(1 μg/L and 10 μg/L) for a short time. Our study suggests that estrogens could cause long-term disturbance to the microbial community of river water ecosystem and provides a theoretical basis for assessing the environmental risk of estrogens in rivers.

Insights into the toxicities of UV-328, UV-329, UV-P in HepG2 cells and their roles in AHR-mediated pathway

The widespread high concentrations of benzotriazole ultraviolet stabilizers (BUVSs) in many biotic and abiotic samples have raised urgent concerns of their adverse effects on environmental and human health. In this study, we investigated the toxicity of three typical BUVSs (UV-328, UV-329, UV-P) with HepG2 cells in vitro. Results indicated that the three BUVSs showed weak cytotoxicity in HepG2 cells at concentrations lower than 50 μM. Transcriptional analysis indicated that the toxic effects of the three chemicals followed the order of UV-P > UV-329 > UV-328. UV-P and UV-329 may act as potential environmental diabetogens by significantly enriching several diabetic related items in both GO and KEGG analysis. Moreover, UV-P and UV-329 significantly upregulated the expression of AHR target genes (CYP1A1, CYP1A2, UGT1A1, etc.), and increased the ethoxyresorufin-O-deethylase (EROD) activity and exhibited agonistic activity toward AHR in the XRE-mediated luciferase reporter gene assay. Molecular docking assay also indicated that UV-329 and UV-P had higher binding affinities to AHR-LBD than UV-328. In brief, our findings indicated that UV-P and UV-329 were potential agonist of AHR ligand, and may exert more toxicity than UV-328 in inducing liver toxicity.

High levels of synthetic antioxidants and ultraviolet filters in children's car seats

Forty-seven compounds among synthetic phenolic and amino antioxidants and ultraviolet filters, three suites of widely used chemical additives, were measured in eighteen popular children's car seats (fabric, foam, and laminated composites of both layers) marketed in the United States in 2018. Significantly higher levels of target compounds were found in foam and composite samples than in fabric samples. Median total concentrations of phenolic antioxidants and their transformation products ranged from 8.11 μg/g in fabric to 213 μg/g in foam In general, isooctyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (AO-1135) and 2,4-di-tert-butylphenol (24-DBP) were the most abundant among all target compounds with maximum levels of526 μg/g in composite and 13.7 μg/g, respectively. The total concentrations of amino antioxidants and their transformation products and of ultraviolet filters were at least one order of magnitude lower than those of phenolic antioxidants, with medians of 0.15-37.1 μg/g and 0.29-1.81 μg/g, respectively, in which the predominant congeners were 4-tert-butyl diphenylamine (BDPA), 4,4'-di-tert-butyl diphenylamine (DBDPA), 4-tert-octyl diphenylamine (ODPA), 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), and 2-(2-benzotriazol-2-yl)-4-methylphenol (UV-P). Large variabilities in usage of these chemicals resulted in different compositional patterns among the car seats. These results suggest that these compounds are major polymeric additives in children's car seats as they are present at greater levels than previously measured groups of chemicals like brominated flame retardants and per- and polyfluoroalkyl substances. Given the documented toxic potentials of synthetic antioxidants and ultraviolet filters, their abundances in children products are a cause for concern.

Occurrence and ecological risks of brominated flame retardants and dechlorane plus in sediments from the Pearl River Estuary and Daya Bay, South China

Considering the phasing-out of polybrominated diphenyl ethers (PBDEs), environmental concerns of PBDE alternatives and dechlorane plus (DP) are rising. Accordingly, this study investigates occurrence and ecological risks of PBDEs, PBDE alternatives and DPs in sediments of two littoral regions, the Pearl River Estuary (PRE) and Daya Bay (DYB), in southern China. Total PBDEs concentrations in surface sediments of the PRE and DYB were in the range (mean) of 0.30-28.7 (8.71) and 0.29-43.4 (6.05) ng/g dw, respectively. DP levels in surface sediments of the PRE (0.004-0.27 ng/g dw) were significantly higher than those in the DYB (0.005-0.24 ng/g dw) (p < 0.05). BDE 209 was the predominant component, followed by DBDPE, exhibiting regional variations in BFRs usage. Vertical profiles of BFRs and DP in the PRE and DYB sediment cores exhibited clear anthropogenic influences. Risk quotients suggest critical ecological risks of tetra-, penta- and deca-BDE congeners in all the surface sediments.

Biological responses of alga Euglena gracilis to triclosan and galaxolide and the regulation of humic acid

Although the toxicity of triclosan (TCS) and galaxolide (HHCB) in freshwater has been reported, little study is shed light on their molecular toxicity mechanism and the regulation of humic acid (HA). In this work, freshwater algae E. gracilis was selected to explore these processes, and the molecular toxicity mechanism was analyzed by metabolomics. TCS was more toxic to E. gracilis than HHCB at 1 d exposure with the EC₅₀ value of 0.76 mg L^-1, but HHCB showed a higher toxicity as the exposure time prolonged. HA could alleviate the toxicity of TCS and HHCB, mainly due to the inhibition of TCS uptake and oxidative stress, respectively. The perturbations on a number of antioxidant defense-related metabolites in response to TCS or HHCB also indicated oxidative stress was a main toxicity mechanism. However, the exposure to HHCB resulted in more pronounced perturbations in the purine metabolism than TCS, implying that HHCB may pose a genetic toxicity on algae. It may explain the higher toxicity of HHCB to algae as the exposure time increased. These findings provide a comprehensive understanding on the ecological risks of TCS or HHCB in natural waters.

Development and validation of a simultaneous method for the analysis of benzothiazoles and organic ultraviolet filters in various environmental matrices by GC-MS/MS

The presence of benzothiazoles (BTHs) and organic ultraviolet filters (UV filters) in aquatic ecosystems has emerged as a significant environmental issue, requiring urgent and efficient determination methods. A new, rapid, and sensitive determination method using gas chromatography triple quadrupole mass spectrometer (GC-MS/MS) was developed for the simultaneous extraction and analysis of 10 commonly used BTHs and 10 organic UV filters in surface water, wastewater, sediment, and sludge. For aqueous samples, solid-phase extraction (SPE) method was employed with optimizing of SPE cartridge type, pH, and elution solvent. For solid samples, ultrasonic extraction-solid-phase extraction purification (UE-SPE) and pressurized liquid extraction (PLE) methods were compared. And extraction conditions for ultrasonic extraction method (extraction solvents and extraction times) and PLE method (extraction temperatures and extraction cycles) were optimized. The limits of quantification for the 20 target compounds in surface water and wastewater were 0.01-2.12 ng/L and 0.05-6.14 ng/L, while those for sediment and sludge with UE-SPE method were 0.04-5.88 ng/g and 0.22-6.61 ng/g, respectively. Among the 20 target compounds, the recoveries ranged from 70 to 130% were obtained for 16, 15, 15, and 15 analytes in the matrix-spiked samples of surface water, wastewater, sediment, and sludge with three levels, respectively. And the precision was also acceptable with relative standard deviation (RSD) below 20% for all analytes. The developed methods were applied for the determination and quantification of target compounds in surface water, sediment, wastewater, and sludge samples collected from two wastewater treatment plants (WWTPs) and the Pearl River in Guangzhou, China. BTHs were frequently detected in surface water and wastewater, while UV filters were mainly found in sediment and sludge. Benzotriazole (BT) and 2-hydroxybenzothiazole (2-OH-BTH) were the two major BTHs in influent wastewater and surface water, respectively, with concentrations up to 966 and 189 ng/L. As for sediment and sludge, 2-(2'-hydroxy-5'-octylphenyl)-benzotriazole (UV-329) was a predominant chemical, detected at concentrations of 111 and 151 ng/g, respectively.

A holistic genome dataset of bacteria, archaea and viruses of the Pearl River estuary

Estuaries are one of the most important coastal ecosystems. While microbiomes and viromes have been separately investigated in some estuaries, few studies holistically deciphered the genomes and connections of viruses and their microbial hosts along an estuarine salinity gradient. Here we applied deep metagenomic sequencing on microbial and viral communities in surface waters of the Pearl River estuary, one of China’s largest estuaries with strong anthropogenic impacts. Overall, 1,205 non-redundant prokaryotic genomes with ≥50% completeness and ≤10% contamination, and 78,502 non-redundant viral-like genomes were generated from samples of three size fractions and five salinity levels. Phylogenomic analysis and taxonomy classification show that majority of these estuarine prokaryotic and viral genomes are novel at species level according to public databases. Potential connections between the microbial and viral populations were further investigated by host-virus matching. These combined microbial and viral genomes provide an important complement of global marine genome datasets and should greatly facilitate our understanding of microbe-virus interactions, evolution and their implications in estuarine ecosystems.

Measurement(s)	bacteria • Archaea • viruses
Technology Type(s)	Shotgun Sequencing
Sample Characteristic - Organism	estuary metagenome
Sample Characteristic - Environment	subtropical estuarine
Sample Characteristic - Location	Pearl river estuary

Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.17139998

Environmental risk assessment of parabens in surface water from a Brazilian river: the case of Mogi Guaçu Basin, São Paulo State, under precipitation anomalies

Parabens are preservatives widely used by industry since these compounds have antifungal properties, relative low cost, and stability over a wide pH range. This study aims to quantify and assess the environmental risks of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in surface water from a Brazilian River, Mogi Guaçu. The State of São Paulo, including the Mogi Guaçu River region, suffered from a period of intense drought and high temperatures, which caused anomalies in river flows and water supply problems. The water samples were collected from 14 locations, along 300 km of river extension, at four different seasons. Samples were previously extracted and pre-concentrated by dispersive liquid-liquid microextraction (DLLME) and later analyzed by ultra-performance liquid chromatography coupled with electrospray ionization in tandem with mass spectrometry (UPLC-ESI-MS/MS) detector. During the sampling period, PP was detected in 89.3% of the water samples, MP in 87.5%, EP in 73.2%, and BP in 48.2%. The sum of parabens' average levels was 42.2 μg L^-1 in Winter, 41.5 μg L^-1 in Summer, 36.6 μg L^-1 in Autumn, and 31.5 μg L^-1 in Spring. These levels can be attributed to the smaller dilution effect caused by the drought period. Also, ecological risk assessment indicated that parabens could take a low, medium, and high risk for target organisms in the measured aquatic environments, especially considering Pimephales promelas where 15% of the samples do not present potential risk, 84% of samples can present medium risk and only 1% have low risk. Besides, the risks for BP are also considerably higher, when almost 40% presents for high risks and 60% for medium risks. The present study indicates worrisome threats to the water source and to allegedly protected biodiversity and, therefore, urgent actions are needed to effectively protect.

Continuous input of organic ultraviolet filters and benzothiazoles threatens the surface water and sediment of two major rivers in the Pearl River Basin

The extensive usage of organic ultraviolet filters (UV filters) and benzothiazoles (BTs) has caused continuous and widespread pollution in the aquatic environment. This study investigated the occurrence of nine organic UV filters and eight BTs in the surface water and sediment of two major drinking water source rivers in the Pearl River Basin (PRB). The detection frequencies of six organic UV filters and seven BTs were above 50% in surface water, while eight target compounds were as high as 100%. Composition profiles revealed that 2-Hydroxybenzothiazole (2-OH-BTH, 1112 ng/L) and 2-Mercaptobenzothiazole (2-SH-BTH, 426.3 ng/L) were the predominant compounds in surface water, while Octyl 4-methoxycinnamate (OMC, maximum concentration, 68.3 ng/g) and UV-329 (18.8 ng/g) were predominant in sediment. Significant positive correlations were observed between water quality parameters (temperature, total phosphorus (TP) and total nitrogen (TN)) and organic UV filters (UV-327 and UV-P), indicating the domestic discharge. The calculated annual flux of targets compounds indicated that West River (WR) promoted more BTs and UV filters to the PRB than North River (NR) (BTs: WR22, 88,517 kg/year; NR13, 15,660 kg/year; UV filters: WR22, 28,332 kg/year; NR13, 1128 kg/year). Significant relationship between the Gross Domestic Product (GDP) and annual flux of BTs (R² = 0.96, p < 0.001), and UV filters (R² = 0.88, p < 0.001) in the rivers were found by regression analysis. UV-329 was detected with medium risk (RQ > 0.1) in all WR surface water samples, and 2-SH-BTH was detected with high risk (RQ > 1) in half of the WR sediment samples. This study provides the first time reports on the organic UV filters and BTs in two major rivers in the Pearl River Basin, and further showed that these two types of contaminants are ubiquitous and with potential risks in surface water and sediment of PRB.

Phase partitioning, transport and sources of Benzotriazole Ultraviolet Stabilizers during a runoff event

Benzotriazole Ultraviolet Stabilizers (BT-UVs) are ubiquitous in the environment, given their wide use as additives in consumer products. Their bio-accumulative and toxic properties are increasingly being scrutinised, evinced by the recent proposition to add UV328 to the Stockholm Convention on Persistent Organic Pollutants. Here, we measured concentrations of six BT-UVs in the dissolved and particulate phases of stream water collected from an urban and rural stream during a runoff event. Under baseflow conditions, the less hydrophobic BT-UVs were present at low concentrations in the dissolved phase, while much higher loads of particulate BT-UVs occurred during stormflow, especially in the urban creek. Time-weighted average BT-UV concentrations were up to 4 times higher in the urban than in the rural creek. BT-UVs were found to be prevalent in water obtained from laundering textiles, which plausibly constitutes a major portion of domestic wastewater, and can serve as a BT-UV source to aquatic waterways. However, the observed dilution of a sewage tracer during the run-off event suggests that unregulated wastewater seepage is not responsible for the high BT-UV loads in storm water. High levels of UV328 and UV234 were detected in a select few plastic debris items collected from the urban watershed and in artificial turf grass, respectively. Whereas this may allow for the leaching of those BT-UVs into the creek, most plastic debris is more likely a sink than a source of BT-UVs. The observed input of particle-bound BT-UVs at the onset of the rain event indicates that most of the BT-UVs reach the creek with contaminated particles that had built up on surfaces during the antecedent dry period. UV328 was the dominant BT-UV in those particles. If such particle build-up occurs on road surfaces, it may suggest that the use of UV328 in automotive applications contributes to their presence in urban storm water.

Occurrence, distribution, and ecological risk assessment of emerging and legacy contaminants in the Kadicha river in Lebanon

The Kadicha river basin in Northern Lebanon is an illustrative example of multiple pressures encountered in the Mediterranean region: it is a small coastal river affected by rapid urbanization, population growth (drastically impacted by the influx of Syrian refugees), and a chronic default of wastewater treatment. In this context, multiple classes of contaminants may attain the river accumulating in sediment. However, very little information is available in the literature on the contamination status in such stressed Mediterranean contexts. This study proposed a first contamination evaluation of a small Mediterranean river submitted to multiple pressures. Two sediment sampling campaigns along sites impacted by increasing urban gradient within the Kadicha river basin were performed to determine the occurrence and the environmental risks of both emerging and legacy contaminants. The results revealed the detection of the 41 studied compounds. The highest concentrations were attained by PAHs and polycyclic musks (up to 311.79, 94.22, and 81.13 ng/g of dry weight for PAH, cashmeran, and galaxolide, respectively). The discontinuous urbanized upstream area and the estuary were the most contaminated areas of the river. An environmental risk assessment showed a hazard quotient (HQ) higher than 1 for both legacy and emerging compounds (EHMC and 4-MBC), indicating a potential risk to benthic species. Monitoring campaigns and implementation of wastewater treatment plants should be encouraged as the anthropogenic pressure on small Mediterranean rivers will increase over the years.

Biodegradation of 4-hydroxybenzoic acid by Acinetobacter johnsonii FZ-5 and Klebsiella oxytoca FZ-8 under anaerobic conditions

4-Hydroxybenzoic acid (4-HBA) is a common organic compound that is prevalent in the environment, and the persistence of 4-HBA residues results in exertion of pollution-related detrimental effects. Bioremediation is an effective method for the removal of 4-HBA from the environment. In this study, two bacterial strains FZ-5 and FZ-8 capable of utilizing 4-HBA as the sole carbon and energy source under anaerobic conditions were isolated from marine sediment samples. Phylogenetic analysis identified the two strains FZ-5 and FZ-8 as Acinetobacter johnsonii and Klebsiella oxytoca, respectively. The strains FZ-5 and FZ-8 degraded 2000 mg·L^-1 4-HBA in 72 h with degradation rates of 71.04% and 80.10%, respectively. The optimum culture conditions for degradation by the strains and crude enzymes were also investigated. The strains FZ-5 and FZ-8 also exhibited the ability to degrade other lignin-derived compounds, such as protocatechuic acid, cinnamic acid, and vanillic acid. Immobilization of the two strains showed that they could be used for the bioremediation of 4-HBA in an aqueous environment. Soils inoculated with the strains FZ-5 and FZ-8 showed higher degradation of 4-HBA than the uninoculated soil, and the strains could survive efficiently in anaerobic soil. This is the first report of 4-HBA-degrading bacteria, belonging to the two genera, which showed degradation ability under anaerobic conditions. This study expound the strains could efficiently degrade 4-HBA in anaerobic soil and will help in the development of 4-HBA anaerobic bioremediation systems.

Human metabolism and kinetics of the UV absorber 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV 328) after oral administration

2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV 328; CAS: 25973-55-1) is an ultraviolet light (UV) absorber which belongs to the class of hydroxy phenol benzotriazoles. Therefore, UV 328 is added to plastics and other polymers due to its photostability to prevent discoloration and prolong product stability which may result in an exposure of consumers. However, information about the toxic effects on humans and the human metabolism are still lacking. In the present study, human metabolism pathways of UV 328 and its elimination kinetics were explored. For that purpose, three healthy volunteers were orally exposed to a single dose of 0.3 mg UV 328/kg bodyweight. UV 328 and its metabolites were investigated in blood and urine samples collected until 48 and 72 h after exposure, respectively. Thereby, previously published analytical procedures were applied for the sample analysis using dispersive liquid–liquid microextraction and subsequent measurement via gas chromatography coupled to tandem mass spectrometry with advanced electron ionization. UV 328 was found to be oxidized at its alkyl side chains leading to the formation of hydroxy and/or oxo function with maximum blood concentrations at 8–10 h after exposure for UV 328-6/3-OH, UV 328-4/3-OH and UV 328-4/3-CO. In contrast, a plateau for UV 328-4/3-CO-6/3-OH levels was reached around 10 h post-dosage. The highest blood levels were found for native UV 328 at 8 h after ingestion. Furthermore, biphasic elimination kinetics in blood were revealed for almost all detected metabolites. UV 328 and its metabolites did not occur in blood as conjugates. The renal elimination kinetics were very similar with the kinetics in blood. However, the prominence of the metabolites in urine was somewhat different compared to blood. In contrast, mostly conjugated metabolites occurred for renal elimination. In urine, UV 328-4/3-CO-6/3-OH was found to be the most dominant urinary biomarker followed by UV 328-6/3-OH and UV 328-4/3-OH. In total, approximately 0.1% of the orally administered dose was recovered in urine within 72 h. Although high levels of UV 328 in blood proved good resorption and high systemic availability of the substance in the human body, the urine results revealed a rather low quantitative metabolism and urinary excretion rate. Consequently, biliary excretion as part of the enterohepatic cycle and elimination via feces are assumed to be the preferred pathways instead of renal elimination.

Fate and biodegradation characteristics of triclocarban in wastewater treatment plants and sewage sludge composting processes and risk assessment after entering the ecological environment

Triclocarban (TCC) has a high detection frequency in soil, rivers, sediments, and organisms, and its ecological risks have attracted substantial attention. In this study, we analyzed the fate of TCC in four wastewater treatment plants (WWTPs) in Zhengzhou, China, the biodegradation characteristics during the composting process, and the ecological risks of TCC when entering different environmental compartments. The concentration of TCC in the influent was 731.1-812.4 ng/L. More than 53.4% of TCC was biodegraded during the wastewater treatment process, and less than 2.5% was retained in the effluent. TCC was effectively removed through microbial degradation and sewage sludge absorption, and there were only minor differences in the different wastewater treatment processes. It is worth noting that more than 38% of TCC was enriched in sewage sludge (1430.1-1663.8 ng/g). The corresponding biodegradation rates of TCC were 65.7% and 82.8% in sewage sludge after 17 days of composting treatment with sawdust and straw as bulking agents, respectively. The estimated results showed that effluent discharge into the city rivers was safe. Composting could effectively degrade TCC and decrease the ecological risk of TCC when applied to sewage sludge.

Fate and distribution of benzotriazole UV filters and stabilizers in environmental compartments from Gran Canaria Island (Spain): A comparison study

Tourism is an economic sector of great importance worldwide. In coastal areas, this activity is associated with the use of personal care products, such as ultraviolet (UV) filters and stabilizers. Therefore, assessing their presence and the exposure of living organisms to the impact of this kind of pollutant in such areas could be especially important. The Canary Islands (Spain) are considered an outermost region, and their main economic activity is based on tourism, both national and international. Thus, this area could be remarkably vulnerable to this kind of pollution, and its characterization could be useful to infer conclusions for other similar regions. With this aim, the occurrence of organic UV filters and stabilizers in different environmental matrices in Gran Canaria Island is presented in this work. Six benzotriazole compounds, UV-P, UV-326, UV-327, UV-328, UV-329 and UV-360, were found in wastewater, seawater, sludge, sediment, seaweed and fish samples. The numerous studies devoted to establishing the distribution of these target compounds in many different matrices on a touristic and particularly overcrowded island such as Gran Canaria can be used to understand the pollution situation in similar locations. The works in which determination procedures using different extraction techniques were optimized and validated for the analysis of liquid and solid samples are summarized. They are critically discussed regarding their characteristics and analytical parameters. This research is of interest to environmental managers specializing in the conservation of coastal areas where tourism is an important industry since the active components of UV filters and stabilizers can bioaccumulate and biomagnify in the trophic chain.

Occurrence and distribution of polyhalogenated carbazoles (PHCs) in sediments from the northern South China Sea

Polyhalogenated carbazoles (PHCs) have been frequently detected in various environments and have gained increasing attention due to their dioxin-like toxicity. In this study, 28 surface sediments and three sediment cores were collected from the northern South China Sea (SCS) to investigate the spatial and temporal distribution trends of PHCs. The total concentrations of PHCs in the surface sediments ranged from 0.25 ng/g to 3.10 ng/g, with a median concentration of 1.50 ng/g. The composition profiles of PHCs in the surface sediments were dominated by 3,6-dichlorocarbazole (36-CCZ), 3,6-dibromocarbazole (36-BCZ), and 1,3,6,8-tetrabromocarbazole (1368-BCZ). The total organic carbon (TOC) based concentrations of 36-CCZ, 1-bromo-3,6-dichlorocarbazole, 1,3,6,8-tetrachlorocarbazole, and 1368-BCZ showed significant positive correlation with water depth (r = 0.58-0.88, p values < 0.01). On the contrary, the TOC based concentration of 2,3,6,7-tetrachlorocarbazole displayed a significant negative correlation with the water depth (r = -0.52, p < 0.01). However, no significant correlation was observed for 3-chlorocarbazole, 36-BCZ, and 1,3,6-tribromocarbazole (p values > 0.05). PHCs in sediment cores showed that congener profiles and concentrations of PHCs remained largely stable throughout the 1890s and 2010s. In addition, all the detected PHCs displayed a significant positive correlation with TOC content of the sediments. These unique spatial and temporal distribution patterns suggest that both terrigenous and natural marine sources contributed the observed PHCs in sediments of the northern SCS.

A Review on the Fate of Legacy and Alternative Antimicrobials and Their Metabolites during Wastewater and Sludge Treatment

Antimicrobial compounds are used in a broad range of personal care, consumer and healthcare products and are frequently encountered in modern life. The use of these compounds is being reexamined as their safety, effectiveness and necessity are increasingly being questioned by regulators and consumers alike. Wastewater often contains significant amounts of these chemicals, much of which ends up being released into the environment as existing wastewater and sludge treatment processes are simply not designed to treat many of these contaminants. Furthermore, many biotic and abiotic processes during wastewater treatment can generate significant quantities of potentially toxic and persistent antimicrobial metabolites and byproducts, many of which may be even more concerning than their parent antimicrobials. This review article explores the occurrence and fate of two of the most common legacy antimicrobials, triclosan and triclocarban, their metabolites/byproducts during wastewater and sludge treatment and their potential impacts on the environment. This article also explores the fate and transformation of emerging alternative antimicrobials and addresses some of the growing concerns regarding these compounds. This is becoming increasingly important as consumers and regulators alike shift away from legacy antimicrobials to alternative chemicals which may have similar environmental and human health concerns.

Developing interim water quality criteria for emerging chemicals of concern for protecting marine life in the Greater Bay Area of South China

This study aimed to establish marine water quality criteria (MWQC) for emerging chemicals of concern (ECCs) for protecting aquatic life in the Greater Bay Area (GBA) of South China. Despite the frequent occurrence and elevated concentrations of these ECCs in the GBA, there is a lack of regional MWQC for these contaminants. We screened 21 common ECCs that were classified into the following six groups: (1) new persistent organic contaminants; (2) brominated flame retardants; (3) perfluoroalkyl and polyfluoroalkyl substances; (4) pharmaceutically active compounds (PhACs); (5) plasticizers; and (6) personal care products. Globally, MWQC for PhACs remain largely unavailable despite their increasing occurrence in marine environments. Using an integrative scientific approach, we derived interim MWQC for the GBA with specific protection goals. The approach described herein can be applied for the derivation of MWQC for ECCs and the establishment of guidelines for ecological risk assessment in the GBA and other regions.

A year-long passive sampling of phenolic endocrine disrupting chemicals in the East River, South China

The occurrence of endocrine disrupting chemicals (EDCs) in the aquatic environment is a global concern. In this study, we employed two different passive samplers Diffusive Gradients in Thin-films (DGT) and Chemcatcher for in situ measurement of 8 phenolic EDCs in the East River of the Pearl River system over one-year. These data were assessed alongside results from traditional grab sampling. Six chemicals (4tOP, 4NP, BPA, E1, EE2 and DES) were regularly detected in the water samples, of which the three phenols (i.e. 4tOP, 4NP and BPA) were in all samples and at high concentrations (0.4-1040 ng/L for 4tOP, 2.6-58500 ng/L for NP and 11.4-123300 ng/L for BPA). Fewer target chemicals were detected in both passive samplers, with only 4tOP, 4NP and BPA found in most samplers; E1 and DES were occasionally measurable above detection limits. The higher (by about a factor of 2-3) measurements provided by DGT compared to Chemcatcher could be attributed to the effect of the diffusive boundary layer on Chemcatcher uptake or the strong adsorption of target chemicals on the Chemcatcher PES filter. The temporal trends of EDC monthly loadings indicated that they were from different sources and that WWTPs were not effective in EDC removal and/or there was still some untreated wastewater discharged into the rivers.

Dispersive liquid-liquid microextraction (DLLME) and external real matrix calibration for the determination of the UV absorber 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV 328) and its metabolites in human blood

2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV 328; CAS: 25973-55-1) is a benzotriazole ultraviolet light (BUV) absorber which is applied to plastics and other organic substances to prevent discoloration and enhance product stability. Therefore, UV 328 is frequently used as a plastic additive and may lead to an exposure of consumers. For a reliable assessment of UV 328 metabolism, an analytical method applying dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography tandem mass spectrometry and advanced electron ionization was developed which allows the determination of UV 328 and six of its metabolites in human whole blood. Sample preparation was optimized with respect to DLLME parameters. A critical aspect of the procedure was the application of spiked human blood for calibration, which proved to be essential for achieving accurate results. Validation of the method resulted in limits of detection of 0.1 μg/L for all analytes. Variation coefficients ranged from 2 to 9% for intraday precision and from 3 to 11% for interday precision. Furthermore, relative recovery rates between 80 and 100% were calculated. Afterwards, the procedure was successfully applied to blood samples collected from a volunteer orally exposed to a single dose of UV 328. The method proved to be highly sensitive, repeatable and robust for all compounds and may further be used for studies to elucidate the human metabolism and kinetics of UV 328 and for biomonitoring of specific, environmental and occupational exposure to this UV stabilizer.

Broad Exposure of the North American Environment to Phenolic and Amino Antioxidants and to Ultraviolet Filters

The present study provides a comprehensive investigation of three suites of commonly used synthetic additives: phenolic and amino antioxidants and ultraviolet filters. The concentrations of 47 such compounds and their transformation products were measured in 20 atmospheric particle samples collected in Chicago, in 21 Canadian e-waste dust samples, in 32 Canadian and United States' residential dust samples, and in 10 sediment samples collected from the Chicago Sanitary and Ship Canal. Despite their large production volumes in the United States, environmental data on antioxidants and UV filters in North America is limited. These compounds were detected in all the samples, indicating their ubiquitous distribution in the North American environment. The most prevalent compounds were 2,6-di-t-butyl-p-benzoquinone, diphenylamine, 4,4'-di-t-octyl diphenylamine, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. The e-waste dust contained significantly greater total concentrations of these compounds than the Canadian residential dust, while intermediate levels were detected in the United States residential dust. The sediment samples showed relatively high levels of N,N'-diphenylbenzidine, the source of which is unclear, and some benzotriazole UV filters. Daily intake rates by dust ingestion for these compounds ranged from 1-10 ng/(kg·day) for adults to 10-100 ng/(kg·day) for toddlers. Due to the wide distribution of these compounds in both the ambient and built environments, future research on their potential toxic effects on people and ecosystems is important.

The impact of discharge reduction activities on the occurrence of contaminants of emerging concern in surface water from the Pearl River

"Swimming across the Pearl River" is an annual large-scale sporting event with great popularity in Guangzhou. To reduce the risk of swimmers' exposure to various contaminants in the Pearl River during swimming activities, the local government limits direct sewage and effluent discharge from urban channels during the event. However, the impact of discharge reduction on some contaminants of emerging concern (CECs), such as organophosphorus flame retardants (OPFRs), bisphenol analogues (BPs), and triclosan remains unknown. In the present study, the concentrations of CECs, as well as ammonia-nitrogen (NH₃-N), dissolved organic carbon, and chemical oxygen demand, were measured in aqueous and suspended particulate matter (SPM) from the Guangzhou reaches of the Pearl River. The concentration ranges of sixteen OPFRs, eight BPs, and triclosan were 21.2-91.0, 8.46-37.3, and 1.47-5.62 ng/L, respectively, in aqueous samples, and 25.2-492, 14.0-86.3, and 0.69-17.5 ng/g, respectively, in SPM samples. Hydrophobic and π-π interactions could be contributing to the distribution of CECs. Principal component analysis indicated that consumer materials, manufacturing, and domestic sewage might be the main sources of the CECs. In addition, our study showed that the concentrations of CECs did not change considerably before or after discharge reduction activities, although NH₃-N showed a substantial decrease following pollution control measure. The results demonstrated that temporary reductions of contaminant discharges to the Pearl River had only limited effect on the levels of CECs. Further research is needed to investigate the distributions and potential health risks of CECs in the Pearl River.

Spatial Variation in Bacterioplankton Communities in the Pearl River, South China: Impacts of Land Use and Physicochemical Factors

River ecosystems are critical for human and environmental health, with bacterioplankton playing a vital role in biogeochemical cycles. Unveiling the spatial patterns of bacterioplankton communities in relation to environmental factors is important for understanding the processes of microbial variation and functional maintenance. However, our understanding of the correlations among bacterioplankton communities, physicochemical factors, and land use, especially in large rivers affected by intensive anthropogenic activities, remains relatively poor. Here, we investigated the bacterioplankton communities in July 2018 in three main tributaries of the Pearl River, i.e., Beijiang, Xijiang, and Pearl River Delta, based on 16S rRNA high-throughput sequencing. Results showed that the most dominant phyla, Proteobacteria, Actinobacteria, Cyanobacteria, and Planctomycetes accounted for 33.75%, 22.15%, 11.65%, and 10.48% of the total abundance, respectively. The bacterioplankton communities showed remarkable differences among the three tributaries in terms of composition, structure, diversity, and predictive functional profiles. Mantel and partial Mantel tests revealed that the bacterioplankton communities were affected by physicochemical variables (p < 0.01) and land use (p < 0.01). Redundancy analysis identified specific conductivity, dissolved oxygen, agricultural land, ammonium, urban land, and water transparency as the dominant environmental factors influencing the bacterioplankton communities in the Pearl River. Variation partitioning analysis indicated that both physicochemical factors and land use had direct effects on the bacterioplankton community, and that land use may also shape bacterioplankton communities through indirect effects of physicochemical factors on riverine ecosystems. This study provides fundamental information on the diversity, spatial patterns, and influencing factors of bacterioplankton communities in the Pearl River, which should enhance our understanding of how such communities change in response to environmental gradients and anthropogenic activities.

Food-Borne Exposure of Juvenile Rainbow Trout (Oncorhynchus mykiss) to Benzotriazole Ultraviolet Stabilizers Alone and in Mixture Induces Specific Transcriptional Changes

Benzotriazole ultraviolet-stabilizers (BZT-UVs) are commonly used as additives to protect from light-induced degradation in a variety of consumer goods. Despite their widespread presence in aquatic ecosystems, information on the effects of these compounds remains largely unknown. The objectives of the present study were to evaluate the chronic effects of 2 BZT-UVs alone and in a mixture, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UV-234) and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), in juvenile rainbow trout (Oncorhynchus mykiss) chronically exposed (for 28 d) through the diet. Chemical analyses of livers from exposed trout suggested liver accumulation and potential metabolism of the 2 compounds. Hepatic RNA-sequencing analyses revealed specific effects of each compound on gene transcription profiles; UV-234 affected mainly genes involved in cellular metabolism, whereas UV-328 induced the transcription of ribosomal proteins and downregulated genes involved in immune responses. Both compounds regulated iron homeostasis genes in an opposite manner. The mixture of both BZT-UVs did not produce significant evidence of additive or synergistic effects. Environ Toxicol Chem 2020;39:852-862. © 2020 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry © 2020 SETAC.

Spectroscopic and molecular-level characteristics of dissolved organic matter in the Pearl River Estuary, South China

Coastal populations are expanding globally, resulting in great anthropogenic impacts on the organic matter in estuaries and regional carbon cycles. However, the molecular-level characteristics of dissolved organic matter (DOM) within highly disturbed estuaries are still not well understood. Here, water samples collected during two seasons (wet and dry) from the subtropical Pearl River Estuary of China were analyzed using absorption and fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to determine the spatiotemporal variations in the DOM characteristics. In the seaward direction, the abundances of chromophoric and fluorescent DOM decreased by greater percentages than the bulk dissolved organic carbon concentration. The spectroscopy and FT-ICR MS analyses collectively indicated seaward declines in the aromaticity of DOM and terrestrial DOM contributions from natural terrestrial markers and anthropogenic synthetic surfactants. In particular, the S content in DOM was much higher here than in previously reported estuaries, suggesting a strong anthropogenic impact on the estuarine DOM. Greater terrestrial and anthropogenic signatures in DOM were observed in the wet season than in the dry season. Importantly, this study implies that the terrestrial and anthropogenic contributions to DOM were strongly driven by season in the anthropogenically disturbed subtropical estuary.