Organophosphate esters (OPEs) have raised significant concerns owing to their pervasive environmental occurrence and potential health impacts. This study systematically evaluated the concentrations of OPEs, their associations with environmental and anthropogenic factors, and the potential health risks across seven tea categories in China. Total OPE concentrations ranged from 4.36 to 89.83 ng/g dry weight (dw) (mean: 17.85 ng/g dw), indicating their ubiquitous presence across all tea samples. Health-oriented tea, with a mean concentration of 34.47 ng/g dw, exhibited the highest contamination levels among the various types of tea. The OPE levels in tea were influenced by a combination effect of factors, including planting region, fermentation process, packaging materials, and storage duration. The daily intake of OPEs through tea consumption in China is considered negligible (hazard quotient < 0.1). This comprehensive analysis not only advances our understanding of OPE migration pathways but also provides a scientific foundation for food safety optimization.

Organophosphate esters (OPEs), a class of extensively utilized halogenated flame retardants and plasticizers, have emerged as ubiquitous environmental contaminants and have been detected in multiple matrices, posing potential ecological risks. In this study, we firstly investigated the particle-dissolved phase partition and enrichment of nine OPE compounds in the surface microlayer (SML) of a subtropical urban lake, and further estimate their influence to the air-water exchange process. The concentrations of ∑9OPEs in the dissolved and particle phases of the lake SML were 187-2.36 × 103 ng/L (average: 1100 ± 697 ng/L) and 64.0-294 ng/L (average: 133 ± 62.9 ng/L), respectively. Consistent with the subsurface water (SSW) of the lake, tris (1-chloro-2-propyl) phosphate (TCPP) and tris (2-chloroethyl) phosphate (TCEP) were the predominant OPEs in the SML. The particle fractions (fp) of OPEs in the SML were significantly positively related with their logKow values (p < 0.05), suggesting that OPEs with greater hydrophobicity were more likely to distribute in the particle phase. Significant enrichment of OPEs was observed in both the dissolved and particle phases of the SML, with enrichment factors (EFs) ranging from 0.78 to 409 and from 0.11 to 24.0, respectively. More hydrophobic OPEs also prefer to be enriched in the particle phase of the SML. The comparison of fugacity fractions and exchange fluxes of OPEs between air-SML and air-SSW in the lake demonstrated that the enrichment of OPEs in the SML would alter their air-water exchange processes, highlighting the need to incorporate microlayer-induced concentration gradients into the environmental fate modeling of OPEs.

Microplastics (MPs) and ultraviolet stabilizer-328 (UV-328) are prevalent emerging pollutants in aquatic environments, yet their combined toxicity remains poorly understood. This study investigated the individual and joint toxicity of polystyrene microplastics (PS-MPs, 1000 µg/L) and UV-328 (1, 10, and 100 µg/L) on the early development of zebrafish (Danio rerio), revealing novel insights into their synergistic interactions. It was found that PS-MPs and UV-328 acted synergistically to induce developmental toxicity in zebrafish larvae and triggered oxidative stress responses. Transcriptome analysis and qRT-PCR validation showed co-activation of the peroxisome pathway and FoxO signaling pathway as compensatory antioxidant responses after co-exposure. However, this response was insufficient to counteract oxidative damage, and it still led to an exacerbation of cellular oxidative stress. The neurotoxicity caused by co-exposure to UV-328 and PS-MPs in zebrafish larvae was primarily attributed to disruption of the cholinergic signaling pathway. Notably, the neurotoxic effects were partially attenuated at higher concentrations of UV-328. The mechanism might involve upregulation of the Gap43 gene and activation of the mTOR signaling pathway. This study had revealed a new mechanism for the combined toxicity of microplastics and coexisting pollutants on aquatic organisms, emphasizing the need to consider the synergistic effects of pollutants in environmental risk assessment and management. These findings provided a scientific basis for formulating more comprehensive ecological protection strategies.

As an emerging pollutant, ultraviolet stabilizer-328 (UV-328) has been frequently detected in aquatic environments and attracted great attention. Nevertheless, the toxicity and mechanisms of UV-328 to aquatic organisms are still not fully understood. In particular, the immunotoxicity and neurotoxicity of UV-328 to aquatic organisms and their mechanisms have not been reported yet. In this experiment, the developmental toxicity, oxidative stress, apoptosis, immunotoxicity and neurotoxicity in zebrafish embryos exposed to UV-328 with concentrations of 0.01, 0.1, 1, 10 and 100 µg/L for 120 h were studied. By measuring the growth and developmental indices, production of ROS, enzyme activities, MDA content and expression of genes related to oxidative, immune and nerve, and histopathological analysis, it was found that UV-328 had developmental toxicity to zebrafish larvae, and could induce oxidative stress, immunotoxicity and neurotoxicity to zebrafish larvae even at environmental concentrations with concentration-dependent effects. Moreover, the results of transcriptome analysis and qRT-PCR validation suggested that immune and nerve disorders were caused by UV-328 in zebrafish larvae through regulating the RIG-I-like receptor signaling pathway and neuroactive ligand-receptor interaction, respectively. In addition, transcriptome analysis further revealed that UV-328 could mediate the RIG-I to induce oxidative stress through p38-MAPK/p53 signaling pathway, leading to apoptosis and oxidative damage. In addition, the p38-MAPK signaling pathway enhanced ROS production and activated inflammatory cytokines to induce immunotoxicity. The results of the present work provided important information for understanding the toxicity of UV-328 to aquatic organisms and evaluating its ecological risk in aquatic environment.

As emerging pollutants prevalent in environments and biota, tri-n-butyl phosphate (TnBP) and microplastics (MPs) are harmful to aquatic organisms. Nevertheless, the combined toxicity of TnBP and MPs to aquatic organisms at environmental concentrations is still unknown. In this study, the co-toxic effects of both TnBP and micro/nano-polystyrene (MNPS) in Daphnia magna (D. magna) at environmental relevant concentrations were investigated for the first time. The results suggested that after 21 days of exposure to TnBP (1 μg/L) and MNPS (1 mg/L) alone or in combination, the expression of genes associated with growth and reproduction significantly decreased compared to the control group (p < 0.05), suggesting that MNPS and TnBP exerted growth and reproductive toxicity to D. magna. Moreover, the co-exposure group had lower gene expression levels compared to the single exposure group, implying that combined exposure could exacerbate toxicity impacts on D. magna’s development and reproduction. The activities of enzymes related to oxidative stress and MDA levels in co-exposed group were higher than those in TnBP group, indicating that the MNPS enhanced TnBP-induced oxidative damage to D. magna. In addition, NPS might have caused greater oxidative stress and damage to D. magna than MPS, as higher enzyme activities and MDA levels were observed in the NPS groups. This study provided important information for a comprehensive understanding of the combined aquatic toxicity of MNPS and TnBP at environmental concentrations.

The potential threat of airborne microplastics to human health has attracted widespread attention, especially in large cities with high concentrations of these particles. This study performed a preliminary investigation to uncover the occurrence, potential sources and risks of airborne microplastics in Guangzhou, a highly urbanized megacity of South China. The results suggested that the concentrations of airborne microplastics in Guangzhou ranged from 0.5 to 6.7 particles/m3, with an average of 2.5 ± 1.4 particles/m3. The concentrations of atmospheric microplastics at the sampling site near the heavy traffic area (mean: 3.7 ± 1.7 particles/m3) were significantly higher than at other sampling sites (p < 0.05). Temporally, the atmospheric microplastic concentrations were lowest in the morning (mean: 1.9 ± 1.2 particles/m3), indicating the impact of human activities and air temperatures. Four shapes (including fiber, fragment, foam and film) of microplastics were observed, among which fiber was the main shape and most of them were in the range of 50–300 µm. Rayon and polyethylene terephthalate were the predominant polymer types in fibrous microplastics, indicating that such microplastics primarily originated from synthetic textiles. Human exposure to airborne microplastics via inhalation was estimated to be 4.1 × 103–12.18 × 103 particles/yr. The ecological risk level of fibrous microplastic polymers in the atmosphere of Guangzhou was classified as hazard level II. The findings of the study are helpful for understanding the pollution status and potential risks of airborne microplastics in megacities, and highlight the necessity of long-term monitoring of urban atmospheric microplastic pollution.

As an emerging organic pollutant, tributyl phosphate (TnBP) can be easily adsorbed by microplastics, resulting in compound toxic effects. In the present work, the effects of polystyrene microplastics (PS-MPs) and TnBP on the survival, growth, reproduction and oxidative stress of Daphnia magna (D. magna) have been evaluated through multigenerational test. Compared with the alone exposure groups, the somatic growth rate and the expression values of growth related genes rpa1, mre11, rnha, and rfc3_5 in the F-1 generation of the combined exposure groups were significantly lower (p < 0.05), indicating synergistic effect of PS-MPs and TnBP on the growth toxicity and transgenerational effects. In addition, compared with the PS-MPs groups, significantly lower average number of offspring and expression values of reproduction related genes ccnb, mcm2, sgrap, and ptch1 were observed in the combined exposure group and TnBP group (p < 0.05), indicating TnBP might be the major factor causing reproductive toxicity to D. magna. Although PS-MPs and TnBP alone or in combination also had toxic impacts on the growth, survival and reproduction of D. magna in generations F-0 and F-2, the effects were less than F-1 generation. Regarding oxidative stress, the activity of SOD, CAT and GSH-Px and MDA content in the generations F-0 and F-1 of combined exposure groups were higher than the TnBP group but lower than the PS-MPs groups, suggesting that PS-MPs might be the dominant cause of the oxidative damage in D. magna and the presence of TnBP would alleviate oxidative stress by reducing the bioaccumulation of PS-MPs. The present work will provide a theoretical basis for further understanding of the toxic effects and ecological risks of combined TnBP and microplastic pollution on aquatic organisms.

Tire wear compounds N-(1,3-dimethylbutyl)-N '-phenyl-p-phenylenediamine (6PPD) and its derivative 6PPD-quinone have been considered as emerging pollutants and attracted much attention recently. As an antioxi-dant and antiozonant widely used, 6PPD would be released during the production or use of rubber-related products. Because of the mass production and wide use of rubber-related products, 6PPD and 6PPD-quinone have been identified to be ubiquitous in the environment. In this study, we firstly reviewed the current avail-able literature on the analytical procedures, concentrations and distribution of 6PPD and 6PPD-quinone, and then investigated the potential toxic effects of these two compounds on aquatic organisms. Current studies have been mainly focused on the occurrence of 6PPD and 6PPD-quinone in dust and water, while available infor-mation on atmosphere, soil, sediments and organisms is limited. The fate and distribution of 6PPD and 6PPD-quinone would be influenced by environmental factors such as temperature, illumination, and storm events, etc. Although 6PPD and 6PPD-quinone have potential adverse effects on aquatic organisms, and 6PPD-quinone has species-specific toxicity, toxicological mechanisms of these compounds are still unclear. Based on the review and analysis of current studies, some suggestions for future research of 6PPD and 6PPD-quinone are given.

China is the world's largest consumer of cigarettes. However, the potential cancer risk posed by polycyclic aromatic hydrocarbons (PAHs) in mainstream cigarette smoke, especially species other than benzo[a]pyrene (BaP) remains unclear. In this study, we collected yield data on multiple PAH species from a variety of cigarettes in the China market and calculated their smoking-related incremental lifetime cancer risk (ILCR) values. The computed ILCRs of the total PAHs (ILCRΣPAHs) for ≥95% of the brands were one order of magnitude higher than the acceptable level. ILCRBaP accounted for only 5.0%-37.7% of ILCRΣPAHs among brands, indicating that using single analyte BaP to represent ΣPAHs would significantly underestimate ILCRΣPAHs. No clear trend of changes in ILCRΣPAHs was found for Chinese cigarettes over multiple years, suggesting that smoking cessation is still the best option to minimize the cancer risk of PAHs. The comparison study showed that rarely reported PAHs from Chinese cigarettes can contribute over half of ILCRΣPAHs for several American cigarettes, highlighting the imperativeness to improve the diversity of analytes for Chinese cigarettes. Adults would need to inhale the air-borne PAHs with a BaP equivalent concentration of at least 53.1 ng/m3 to reach the ILCR value comparable to that obtained from smoking.

Most of pathogenic microorganisms in the atmosphere exist in the aerosol, adhering to airborne particulate matters (PM). As a kind of suspended particulate matter, airborne microplastics are also good shelters for pathogenic microorganisms. Nevertheless, data on the occurrence characteristics of pathogens on airborne microplastics are quite limited. In this review, we summarized the analytical method of microorganisms on PM, investigated the composition of (pathogenic) microorganisms on PM and their affecting factors, and further explored the potential interaction between airborne PM (microplastics) and pathogenic microorganisms. Bacteria and fungi are dominant microorganism in the air. The species, population and activity of microorganisms in the air may change with many factors including nature of PM, temperature, relative humidity, etc. As carrier for pathogenic microorganisms, atmospheric transport of PM (microplastics) will facilitate the widespread distribution of pathogenic microorganisms in the environment and their entry to human lungs. The PM (microplastics) themselves and the substances absorbed on them can enhance the pathogenesis of microorganisms. On the other hand, PM (microplastics) and the adherent toxic chemicals may be harmful to the airborne (pathogenic) microorganisms. To further understand the interactions between microplastics and pathogenic microorganisms, there are still a lot of work to be done.

Wastewater treatment plants (WWTPs) discharge metric tons of microplastics (MPs) daily to aquatic and terrestrial environments worldwide. Herein we provide a holistic review on MPs in the WWTPs, highlighting recent advances in sampling and analysis, improved understanding of their sources, occurrence, and degradation in treatment steps, and the potential risks MPs pose after being discharged in treated effluent and sludge. We discuss the merits and limitations of the various sampling and analytical approaches to determine MPs in major WWTP compartments; highlight new research on MP profiles (abundance, physical characteristics, and compositions) in raw sewage, treated effluent, and waste sludge, which are of particular interest when assessing MP sources, removal rates, and fate; and emphasize mechanisms of MP fragmentation and degradation within WWTPs as well as the potential sorption of wastewater contaminants to the MPs. We find that robust and standardized methods for determining MPs in WWTP samples is still urgently needed, and that complete removal of MPs from wastewater by WWTPs is not guaranteed, although the vast majority of MPs end up in sludge. Areas of research that deserve further attention include the fate of small (<20 μm) MPs, abiotic and biotic fragmentation of MPs in the WWTPs, and more empirical data with concentrations on a mass basis.

The environmental-friendly photocatalytic process with a magnetic catalyst CoFe2O4/TiO2 mediated by solar light for ibuprofen (IBP) degradation in pure water, wastewater effluent and artificial seawater was investigated systematically. The study aims to reveal the efficiency, the mechanism and toxicity evolution during IBP degradation. Hydroxyl radicals and photo-hole (h(+)) were found to contribute to the IBP decay. The presence of SO42- showed no significant effect, while NO3- accelerated the photodegradation, and other anions including HOC3-, Cl-, F-, and Br- showed significant inhibition. The removal efficiency was significantly elevated with the addition of peroxymonosulfate (PMS) or persulfate (PS) ([Oxidant](0):[IBP](0) = 0.4-4), with reaction rate of 5.3-13.1 and 1.3-2.9 times as high as the control group, respectively. However, the reaction was slowed down with the introduction of H2O2. A mathematic model was employed to describe the effect of ferrate, high concentration or stepwise addition of ferrate was suggested to play a positive role in IBP photodegradation. Thirteen transformation products were identified and five of them were newly reported. The degradation pathways including hydroxylation, the benzene ring opening and the oxidation of carbon were proposed. IBP can be efficiently removed when spiked in wastewater and seawater despite the decreased degradation rate by 41% and 56%, respectively. Compared to the IBP removal, mineralization was relatively lower. The adverse effect of the parent compound IBP to the green algae Chlorella vulgaris was gradually eliminated with the decomposition of IBP. The transformation product C178a which possibly posed toxicity to rotifers Brachionus calyciflorus can also be efficiently removed, indicating that the photocatalysis process is effective in IBP removal, mineralization and toxicity elimination. (C) 2021 Published by Elsevier Ltd.

Organophosphate flame retardant (OPFR) pollution in marine environment has attracted increasing attention in recent years. Coral reefs are regarded as significant marine ecosystems, however, research on OPFR contamination in coral reefs is limited. In the present work, 9 OPFR compounds were analyzed in fish samples collected from the Zhubi Reef and Yongshu Reef of the Nansha Islands, South China Sea, to evaluate the biomagnification and potential threats of OPFRs in the coral reef ecosystems. n-ary sumation OPFR concentrations in the coral reef fish ranged from 38.7 to 2090 ng/g lipid weight (lw), with an average of 420 +/- 491 ng/g lw. Alkyl OPFRs were more abundant than chlorinated OPFRs and aryl OPFRs. Individually, TBEP and TCPP were the two most abundant OPFR compounds. Biomagnification potential was indicated for TCPP, TCEP, TBP, TBEP and TEHP along the marine food web, with trophic magnification factors being greater than one. The estimated dietary intakes of OPFRs via coral fish consumption were 0-1.11 ng/kg bw/d and 0.01-2.06 ng/kg bw/d, respectively, for rural and urban residents. Additionally, the hazard quotients of OPFR compounds ranged from 2 x 10-7 to 7.41 x 10-5 for rural residents and from 4 x 10-7 to 1.37 x 10-4 for urban residents. Although the risk to human health from exposure to OPFRs via consuming coral reef fish from the South China Sea was low, further investigation of these chemicals is still recommended.

As an issue of great concern, microplastics pollution has emerged as a key environmental challenge of our time. The atmosphere is a significant compartment in the global cycle of microplastics, however, studies on the transport and deposition of airborne microplastics is limited. In the present work, atmospheric wet and dry deposition of microplastics were analyzed over one year in an urban environment of megacity Guangzhou, China. The atmospheric deposition fluxes of microplastics ranged from 51 to 178 particles/m2/d (mean: 114 ± 40 particles/m2/d). Fibers, fragments, films and microbeads were observed in the deposition samples, with fibers being the most abundant microplastics, accounting for 77.6 ± 19.1% of the total. The chemical composition of microplastics were identified using micro Fourier transform infrared spectrometer. 78.7% of the fibrous microplastics were derived from petrochemicals and most were polyethylene terephthalate (polyester), suggesting that textiles (e.g., clothes and curtains) were likely the main source. The results of back-trajectory analysis indicated that city rivers may act as secondary sources of airborne microplastics. Though no significant correlation was found between atmospheric microplastic deposition and meteorological factors such as rainfall and wind events, these factors were suggested to be positive drivers for the transport and deposition of airborne microplastic.

The toxicology of microplastics in combination with other pollutants has attracted widespread attention. In this study, zebrafish were exposed to 3 mg/L polystyrene microplastic, 0.2 mg/L phenanthrene, and a combination of both. Zebrafish microplastic uptake, phenanthrene accumulation, antioxidant-associated enzyme activity and related gene expression, immune-associated gene expression, and the gut microflora were measured after 12 and 24 days of exposure. Phenanthrene and microplastic accumulation increased with exposure time and was also greater in the combined exposure group than in the single exposure group. Combined analysis of antioxidant enzyme activity and immune and antioxidant-related genes shows that exposure alone causes oxidative stress in zebrafish, ultimately increasing immunity and the expression of oxidative stress genes, while combined exposure exacerbates these changes. Fusobacteria decreased and Proteobacteria and Bacteroidetes increased in the three exposure groups of gut microorganisms. Overall, our study demonstrates that microplastics enhance the toxicity of phenanthrene and that the two have a synergistic effect.

Microplastics (MPs) are emerging pollutants and have potential adverse effects to organisms. Airborne MPs are of great concern, because they are an important contributor to MPs in other environmental compartments such as water and soils and may pose potential risk to human health via inhalation or dust ingestion. Analytical methods, abundance, pollution characteristics, potential sources and risk to human beings of airborne MPs in suspended particulates, atmospheric fallout and deposited dusts were summarized in the present review. Research gaps and suggestions for future works on airborne MPs were also given. Digestion of samples was suggested to avoid the interference of organic materials to airborne MPs. New techniques such as hyperspectral imaging technique, pyrolysis and thermal desorption gas chromatography mass spectrometry were expected to be used for the analysis of airborne MPs. Furthermore, more studies were required to fully understand the pollution status and potential risk of airborne MPs.

As emerging persistent organic pollutants in marine environment, short-chain chlorinated paraffins (SCCPs) have attracted increasing attentions recently. Coral reefs are important ocean ecosystems. However, data on SCCP pollution in the coral reef regions is still unavailable. In the present work, bioaccumulation of SCCPs in the coral reef ecosystems was reported for the first time. SCCP concentrations in coral reef fish from the Nansha Islands of the South China Sea were in the range of 37.9-25,400 ng/g lipid weight (lw) (average: 4400 ± 6590 ng/g lw; median: 1020 ng/g lw). C10 SCCPs were the dominating SCCP homologues, accounting for 59% to 80% of the total SCCPs (average: 70 ± 5.0%), followed by C11 SCCPs (average: 23 ± 4.5%). Regarding chlorine substitution, SCCPs were dominated by Cl7 SCCPs (average: 45 ± 2.5%) and Cl8 SCCPs (average: 30 ± 5.4%). Trophic magnification factor (TMF) of total SCCPs was 8.5, indicating trophic magnification potential of SCCPs in the coral reef ecosystems. In addition, a parabolic relationship was established between TMFs and log Kow of specific SCCP homologues. SCCP residues in the coral reef fish from the Nansha Islands of the South China Sea did not pose significant risk to human health.

Salmonella enterica serovar Kentucky (S. Kentucky) sequence type 198 has emerged as a global zoonotic pathogen. We explored Salmonella enterica serovar Kentucky ST198 samples from the broiler chicken supply chain and patients between 2010 and 2016. Here, we collected 180 S. Kentucky isolates from clinical cases and the poultry supply chain. We performed XbaI pulsed-field gel electrophoresis and multilocus sequence typing. We assessed mutations in the quinolone resistance-determining regions and screened for the presence of the Salmonella genomic island 1 (SGI1). We determined that 63 (35.0%) of the 180 isolates were S. Kentucky ST198. Chinese strains of S. Kentucky ST198 have a high transmission of ciprofloxacin resistance (38/63, 60.3%) and a high risk of multidrug resistance. The quinolone resistance of the S. Kentucky ST198 strain found in China may be due to mutations in its quinolone resistance-determining region. Our study firstly revealed that ciprofloxacin-resistant S. Kentucky ST198 strains can undergo cross-host transmission, thereby causing a serious foodborne public health problem in China.

Short-chain chlorinated paraffins (SCCPs) area series of new persistent organic pollutants, posing a risk of significant adverse effects to biota. Increasing attention has been paid to SCCP pollution in China as large amounts of chlorinated paraffin (CP) products containing SCCPs have been produced and used there. However, knowledge of the bioaccumulation of SCCPs in marine organisms from the Pearl River Estuary (PRE), Southern China, is still scarce. In this study, SCCP concentrations were measured in seawater, sediments, and marine organisms from the PRE. SCCP concentrations ranged from 180 to 460 ng/L in seawater, from 180 to 620 ng/g dry weight (dw) in sediments, and from 870 to 36,000 ng/g lipid weight (lw) in marine biota samples. C10-11 SCCPs were the predominant homologues in all the samples, with an average abundance of 68% in seawater, 57% in sediments, and 56-77% in marine organisms. However, chlorine patterns of SCCPs in seawater, sediments, and marine organisms were different. Cl8-10 SCCPs dominated in sediments, whereas Cl5-7 SCCPs were the predominant SCCP homologues in water and most organism species. The logarithm bioaccumulation factors (BAFs) of SCCPs ranged from 1.6 to 3.0, and increased significantly with the increase of K-ow values for most marine biota species, indicating that K-ow was the major factor controlling the bioaccumulation of SCCPs and that SCCPs with higher lipophilicity were more prone to being bioaccumulated from water. Opposite to that observed for log BAFs, biota-sediment accumulation factors of specific SCCPs (range: 0.01-30) decreased significantly with the increase of K-ow values. The biomagnification factor of total SCCPs for oyster-mangrove crab was 2.40, implying the potential biomagnification of SCCPs for benthos in the PRE. (C) 2019 Elsevier B.V. All rights reserved.