Effects of Bisphenol A and Its Substitute, Bisphenol F, on the Gut Microbiota in Mice

Objective The aim of this study was to assess the impact of bisphenol A(BPA)and its substitute,bisphenol F(BPF),on the colonic fecal community structure and function of mice.Methods We exposed 6–8-week-old male C57BL/6 mice to 5 mg/(kg∙day)and 50μg/(kg∙day)of BPA or BPF for 14 days.Fecal samples from the colon were analyzed using 16S rRNA sequencing.Results Gut microbiome community richness and diversity,species composition,and function were significantly altered in mice exposed to BPA or BPF.This change was characterized by elevated levels of Ruminococcaceae UCG-010 and Oscillibacter and decreased levels of Prevotella 9 and Streptococcus.Additionally,pathways related to carbohydrate and amino acid metabolism showed substantial enrichment.Conclusion Mice exposed to different BP analogs exhibited distinct gut bacterial community richness,composition,and related metabolic pathways.Considering the essential role of gut bacteria in maintaining intestinal homeostasis,our study highlights the intestinal toxicity of BPs in vertebrates.

Microplastics in sediment of the Three Gorges Reservoir:abundance and characteristics under different environmental conditions

Freshwater microplastic pollution is an urgent issue of global concern,and research on the distribution in reservoirs is lacking.We investigated the microplastic pollution levels in wet sediments collected from the Three Gorges Reservoir,the largest reservoir of China.Results show that microplastics were ubiquitous in the sediments of the Three Gorges Reservoir,and their abundance ranged from 59 to 276 pp/kg(plastic particles per kg,dry weight).Economic development and total population were important factors affecting the spatial heterogeneity of microplastic abundance,and the contribution of large cities along the reservoir to microplastic pollution should be paid with more attention.Fibrous microplastics were the most abundant type of microplastic particles in reservoir sediments,whereas polystyrene,polypropylene,and polyamide were the main types of polymers.The apparent spatial heterogeneity in morphology and color of microplastics is attributed to different anthropogenic or landbased pollution sources.Moreover,the accumulation of microplastics near the inlet of tributaries reflects the role of potential contributors of tributaries.More importantly,multiple bisphenols(BPs)and heavy metals detected at the microplastic surfaces indicate that microplastics can act as carriers of these pollutants in the environment in the same way as sediments did,which may alter the environmental fate and toxicity of these pollutants.Therefore,we conclude that the Three Gorges Reservoir had been contaminated with microplastics,which posed a stress risk for organisms who ingest them along with their associated pollutants(BPs,heavy metals).

Mechanisms underlying the role of endoplasmic reticulum stress in the placental injury and fetal growth restriction in an ovine gestation model

Background Exposure to bisphenol A(BPA),an environmental pollutant known for its endocrine-disrupting properties,during gestation has been reported to increase the risk of fetal growth restriction(FGR)in an ovine model of pregnancy.We hypothesized that the FGR results from the BPA-induced insufficiency and barrier dysfunction of the placenta,oxidative stress,inflammatory responses,autophagy and endoplasmic reticulum stress(ERS).However,precise mechanisms underlying the BPA-induced placental dysfunction,and subsequently,FGR,as well as the potential involvement of placental ERS in these complications,remain to be investigated.Methods In vivo experiment,16 twin-pregnant(from d 40 to 130 of gestation)Hu ewes were randomly distributed into two groups(8 ewes each).One group served as a control and received corn oil once a day,whereas the other group received BPA(5 mg/kg/d as a subcutaneous injection).In vitro study,ovine trophoblast cells(OTCs)were exposed to 4 treatments,6 replicates each.The OTCs were treated with 400μmol/L BPA,400μmol/L BPA+0.5μg/m L tunicamycin(Tm;ERS activator),400μmol/L BPA+1μmol/L 4-phenyl butyric acid(4-PBA;ERS antagonist)and DMEM/F12 complete medium(control),for 24 h.Results In vivo experiments,pregnant Hu ewes receiving the BPA from 40 to 130 days of pregnancy experienced a decrease in placental efficiency,progesterone(P4)level and fetal weight,and an increase in placental estrogen(E2)level,together with barrier dysfunctions,OS,inflammatory responses,autophagy and ERS in type A cotyledons.In vitro experiment,the OTCs exposed to BPA for 24 h showed an increase in the E2 level and related protein and gene expressions of autophagy,ERS,pro-apoptosis and inflammatory response,and a decrease in the P4 level and the related protein and gene expressions of antioxidant,anti-apoptosis and barrier function.Moreover,treating the OTCs with Tm aggravated BPA-induced dysfunction of barrier and endocrine(the increased E2 level and decreased P4 level),OS,inflammatory responses,autophagy,and ERS.However,treating the OTCs with 4-PBA reversed the counteracted effects of Tm mentioned above.Conclusions In general,the results reveal that BPA exposure can cause ERS in the ovine placenta and OTCs,and ERS induction might aggravate BPA-induced dysfunction of the placental barrier and endocrine,OS,inflammatory responses,and autophagy.These data offer novel mechanistic insights into whether ERS is involved in BPA-mediated placental dysfunction and fetal development.

Advanced oxidation via the synergy of C-defective/C-O band modified ultrathin porous g-C_(3)N_(4)and PMS for efficient photothermal degradation of bisphenol pollutants and lignin derivatives

This work uses thermal polymerization of urea nitrate,oxyacetic acid and urea as the raw material to prepare ultra-thin porous carbon nitride with carbon defects and C-O band(OA-UN-CN).Density functional theory(DFT)calculations showed OA-UN-CN had narrower band gap,faster electron transport and a new internal construction electric field.Additionally,the prepared OA-UN-CN significantly enhanced photocatalytic activation of peroxymonosulfate(PMS)due to enhanced light absorption performance and faster electron overflow.As the result,the OA-UN-CN/PMS could entirely degrade bisphenol A(BPA)within 30 min,where the photodegradation rate was 81.8 and 7.9 times higher than that of g-C_(3)N_(4)and OA-UN-CN,respectively.Beyond,the OA-UN-CN/PMS could likewise degrade other bisphenol pollutants and sodium lignosulfonate efficiently.We suggested possible photocatalytic degradation pathways accordingly and explored the toxicity of its degradation products.This work provides a new idea on the development of advanced photocatalytic oxidation processes for the treatment of bisphenol pollutants and lignin derivatives,via a metal-free photothermal-catalyst.

Fabrication of a novel electrochemical sensor based on MnFe_(2)O_(4)/graphene modified glassy carbon electrode for the sensitive detection of bisphenol A

Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal symmetry.Herein,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposites modified glassy carbon electrode(GCE),which is very efficient and sensitive to detect bisphenol A(BPA).MnFe_(2)O_(4)/graphene(GR)was synthesized by immobilizing the MnFe_(2)O_(4) microspheres on the graphene nanosheets via a simple one-pot solvothermal method.The morphology and structure of the MnFe_(2)O_(4)/GR nanocomposite have been characterized through scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).In addition,electrochemical properties of the modified materials are comparably explored by means of cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).Under the optimal conditions,the proposed electrochemical sensor for the detection of BPA has a linear range of 0.8-400μmol/L and a detection limit of 0.0235μmol/L(S/N=3)with high sensitivity,good selectivity and high stability.In addition,the proposed sensor was used to measure the content of BPA in real water samples with a recovery rate of 97.94%-104.56%.At present,the synthesis of MnFe_(2)O_(4)/GR provides more opportunities for the electrochemical detection of BPA in practical applications.

A novel bellidifolin intervention mitigates nonalcoholic fatty liver disease-like changes induced by bisphenol F

As a potential endocrine-disrupting chemical,bisphenol F(BPF)may cause nonalcoholic fatty liver disease(NAFLD)-like changes,but the mechanisms under its pathogenesis as well as the intervention strategies remain unclear.Using the electron microscopy technology,along with LipidTOX Deep Red neutral and Bodipy 493/503 staining assays,we observed that BPF treatment elicited a striking accumulation of lipid droplets in HepG2 cells,accompanied by an increased total level of triglycerides.At the molecular level,the lipogenesis-associated mRNAs and proteins,including acetyl-CoA carboxylase,fatty acid synthase,stearoyl-CoA desaturase-1,peroxisome proliferator-activated receptor gamma,and CCAAT-enhancer-binding proteins,increased significantly via the AMP-activated protein kinase(AMPK)-mammalian target of rapamycin(mTOR)signaling regulation in both in vitro and in vivo studies.Furthermore,the immunofluorescence results also showed the robust lipogenesis induced by BPF,evident in its ability to promote the translocation of sterol regulatory element-binding protein-1c from the cytoplasm to the nuclei.To investigate the intervention strategies for BPF-induced NAFLD-like changes,we demonstrated that bellidifolin,isolated and purified from Swertia chirayita,significantly attenuated BPF-induced lipid droplet deposition in HepG2 cells and NAFLD-like changes in mice by blocking the expression of lipogenesis-associated proteins.Therefore,the present study elucidates the mechanisms underlying the BPF-induced lipid accumulation in HepG2 cells,while also highlighting the potential of bellidifolin to mitigate BPF-induced NAFLD-like changes.

Garcinia Kola and Kolaviron Attenuates Bisphenol A-Induced Memory Impairment and Hippocampal Neuroinflammation in Male Wistar Rats

Bisphenol A (BPA), a toxicant which can leach into food from plastic containers, is reported to induce neurotoxicity among others via oxidative mechanisms. However, antioxidant compounds have been suggested to mitigate BPA-induced toxicities. Garcinia kola (GK) and its bioactive compound, kolaviron, are well-established natural antioxidants, which can exert protective effects against BPA-induced toxicities. This study was designed to investigate the likely mitigating effect of GK and kolaviron on BPA-induced memory impairment and hippocampal neuroinflammation in male Wistar rats. Thirty-five rats were equally grouped and treated as follows: I and II received distilled water and corn oil, respectively at 0.2 mL, while III - VII received BPA (50 mg/kg), BPA + GK (200 mg/kg), BPA + kolaviron (200 mg/kg), GK and kolaviron, respectively for 28 days p.o. Thereafter, behavioral studies were done using the Novel Object Recognition and Y maze tests. Subsequently under anaesthesia, the hippocampus in each animal was dissected out, homogenized and analysed for malondialdehyde, superoxide dismutase, catalase, reduced glutathione, glutathione transferase, nitrites, interleukin-6, tumour necrosis factor-α, acetylcholinesterase, glutamate acid decarboxylase, and arginase activity. Data were analyzed by ANOVA and Tukey Post-hoc test at p p Garcinia kola and Kolaviron mitigate bisphenol A-induced memory impairment and neuroinflammation via antioxidant potentiation and neurotransmitter balance.

Detection of Bisphenol A (BPA) in Plastic Bottles Using Vertical Cultivation at Various Temperatures

Polycarbonate plastics containing bisphenol A (BPA) used to manufacture drinking water bottles. Kurdistan region in northern Iraq is a developed area with increased pollution from plastic bottles. Trace amounts of BPA have been detected in bottled water samples. The absorption of BPA was measured with HPLC using a vertical cultivation system with Bulbs of the Allium Cepa plant planted in these plastic bottles with monitored growth. Vertical cultivation was found to have a low level of BPA in the plant cells, making it a safe cultivation method under specific climate conditions. The mean concentration of BPA in vertical cultivation is 0.19 ug/ml (3.8 ng for a 20 uL injection), and the Limit of Quantification (LOQ) is 0.63 ug/ml (12.7 ng for 20 uL injection). While Scanning Electron Microscope (SEM) shows that the concentrations are relatively low in water samples stored at room temperature compared to those exposed to direct sunlight (40°C) and water bottle samples stored at (-4°C), The correlation coefficients were found to be good (0.9992). SEM is used for plastic bottle samples stored at different temperatures. The images identify compound decay and explore the morphology of BPA in manufactured plastic materials.

Bisphenol A (BPA) Contamination in Whole Milk Marketed in Different Packages

Bisphenol A (BPA), an important endocrine disruptor, is used in the manufacturing of various materials, including food packaging. Ingestion of contaminated foodstuffs is, in fact, the most relevant form of exposure to this substance. However, scarce data on the presence of this contaminant in milk, or whether different types of food packaging influence food contamination are available in Brazil. This study, therefore, aimed to evaluate the BPA contamination of whole milk (fluid and powder) samples packaged in different types of packaging (Tetra Pak?;PET: Poly (ethylene terephthalate;Metallic can (epoxy resin);Polyethylene (PE) and poly (vinylidene chloride) (PVDC);Laminated Film - Metallized Polyester-Polyethylene and glass) and marketed metropolitan region of Rio de Janeiro, Brazil. An analytical method for the BPA determination in milk was optimized for both fluid (pasteurized and ultra-high temperature) and powdered milk samples. A modified QuEChERS method was applied, and BPA determinations were conducted by ultra-performance liquid chromatography coupled with sequential mass spectrometry (HPLC-MS/MS). The validated method was then applied to 51 milk samples, where BPA was detected in five samples (9.8%) and quantified in two (3.8%).

New environmental factors related to diabetes risk in humans:Emerging bisphenols used in synthesis of plastics

BACKGROUND Diabetes mellitus(DM)is one of the largest global health emergencies of the 21st century.In recent years,its connection with environmental pollutants,such as bisphenol A(BPA),has been demonstrated;consequently,new structurally similar molecules are used to replace BPA in the plastics industry(BPS,BPF and BPAF).AIM To carry out a systematic review to allow coherent evaluation of the state of the art.Subsequently,a meta-analysis was performed to unify the existing quantitative data.METHODS Firstly,a systematic review was carried out,using the terms“(bisphenol)AND(Diabetes OR Hyperglycemia)”,to maximize the number of results.Subsequently,three authors analyzed the set of articles.Finally,a meta-analysis was performed for each BP,using RevMan software.In addition,funnel plots were developed to study publication bias.RESULTS The systematic analysis of the literature revealed 13 recent articles(2017–2023)related to the study paradigm.The qualitative analysis showed interesting data linking diabetes to the three most widely used substitute BPs in the industry:BPS,BPF and BPAF.Finally,the meta-analysis determined a positive relationship with BPS,BPF and BPAF,which was only statistically significant with BPS.CONCLUSION There is a need to apply the precautionary principle,regulating the use of new BPs.Therefore,replacing BPA with BPS,BPF or BPAF is unlikely to protect the population from potential health risks,such as DM.

Food contaminants and potential risk of diabetes development:A narrative review

The number of people diagnosed with diabetes continues to increase,especially among younger populations.Apart from genetic predisposition and lifestyle,there is increasing scientific and public concern that environmental agents may also contribute to diabetes.Food contamination by chemical substances that originate from packaging materials,or are the result of chemical reactions during food processing,is generally recognized as a worldwide problem with potential health hazards.Phthalates,bisphenol A(BPA)and acrylamide(AA)have been the focus of attention in recent years,due to the numerous adverse health effects associated with their exposure.This paper summarizes the available data about the association between phthalates,BPA and AA exposure and diabetes.Although their mechanism of action has not been fully clarified,in vitro,in vivo and epidemiological studies have made significant progress toward identifying the potential roles of phthalates,BPA and AA in diabetes development and progression.These chemicals interfere with multiple signaling pathways involved in glucose and lipid homeostasis and can aggravate the symptoms of diabetes.Especially concerning are the effects of exposure during early stages and the gestational period.Well-designed prospective studies are needed in order to better establish prevention strategies against the harmful effects of these food contaminants.

Bisphenol A in Fluid and Powdered Milk Samples and Associated Child Dietary Exposures

Bisphenol A (BPA) is a synthetic chemical found in a wide range of consumer products and consumables that humans are exposed to. The aim of this study was to determine BPA contamination levels in 51 milk samples sold in the Rio de Janeiro Metropolitan Region, Brazil. Bisphenol A was detected (≥limit of detection, LOD) in five of the analyzed samples (9.8%) and quantified (≥limit of quantification, LOQ) in two (3.8%). The estimated daily intake (EDI) for children aged up to 12 months ranged from 24.95 to 97.72 ng/kg body weight/day, lower than the established European Union tolerable daily intake value. Recent evidence, however, suggests that even low doses of endocrine disruptors such as BPA may pose potential health risks, even more so when exposure occurs at such an early life stage.

两种环境雌激素对发头裸腹溞的急性致毒研究

运用毒理学实验方法,研究双酚A(BPA)和邻苯二甲酸二甲酯(DMP)对发头裸腹溞的急性致毒效应.结果显示:双酚A对发头裸腹溞24、48、72、96 h的半数致死浓度分别为14.129、11.094、9.116、6.815 mg/L;邻苯二甲酸二甲酯对发头裸腹溞24、48、72、96 h的半数致死浓度分别为63.460、15.065、4.272、0.865 mg/L.BPA和DMP对发头裸腹溞的安全浓度分别为0.682 mg/L和0.087 mg/L,其死亡率和上述两种雌激素质量浓度间存在着明显的正相关性,且随着染毒时间的延长半数致死浓度逐渐降低,发头裸腹溞对DMP的敏感性高于BPA.根据化学物质对溞类的毒性评价标准,双酚A和邻苯二甲酸二甲酯分别为中毒和高毒物质.

Limiting the Migration of Bisphenol A from Polycarbonate Using Dielectric Barrier Discharge

Dielectric barrier discharge is used as a cheap technique for surface treatment of polycarbonate. The discharge system is working in open air at atmospheric pressure. The treatments are carried out at low discharge powers (1.5 and 2 W) for treatment time (2.5 - 15 min). The treated samples show decrease in the contact angle and increase in the crystallinity, thermal stability and surface roughness. The effect of ozone on the increase in the oxygen containing functional groups is discussed. The treatment process shows effective limitation of the migration of bisphenol A from the surface of polycarbonate due to the cross linking. Zero migration of bisphenole A is recorded as the sample is treated for 7.5 min. The treatment process is found to be very efficient with very low cost.

Simultaneous determination of 4-tert-octylphenol, 4-nonylphenol and bisphenol A in Guanting Reservoir using gas chromatography-mass spectrometry with selected ion monitoring

The wide occurrence of estrogenic compounds 4-tert-octylphenol, 4-nonylphenol, bisphenol A in surface water of Guanting Reservoir was successfully determined. The target compounds in water samples were preconcentrated by liquid-liquid extraction with dichloromethane, derivatized by trifluoroacetic anhydride, and quantified by gas chromatography-mass spectrometry(GC-MS) with selected ion monitoring(SIM). In the selected seven sampling sites(S1\_S7), the concentration of NP in sample S7 was significantly higher than the other in reservoir. The status of pollution in S3 and S7 were much more serious. The concentrations of OP, NP and BPA were in the range of 44.5—48.8, 221.6—349.6 and 30.2—82.7 ng/L, respectively. The pollutants were mainly inputted from the upper river and released from sediments in Guanting Reservoir.

A Study on Bisphenol A,Nonylphenol,and Octylphenol in Human Urine amples Detected by SPE-UPLC-MS

Objective To establish a comprehensive analytical method based on SPE‐UPLC‐MS for the simultaneous determination of bisphenol A （BPA）, nonylphenol （NP）, and octylphenol （OP） in urine samples. Methods Sixty urine samples collected from healthy subjects were analyzed for BPA, NP, and OP concentrations. The samples were de‐conjugated by adding β‐glucuronidase and sulfatase. After the enzymatic treatment, the samples were subjected to the OASIS HLB column solid phase extraction cartridges so as to be cleaned and concentrated. The UPLC separation was performed on a Acquity UPLCTM BEH C18 column （2.1×100 mm, 1.7 μm） with a gradient elution system of methanol‐water as the mobile phase. Triple‐quadrupole mass spectrometry analyzer was used for the qualitative and quantitative analysis of UPLC‐MS/MS system. Results The limit of detection of BPA, NP, and OP was 0.10, 0.10, and 0.15 ng/mL, respectively. The recoveries of BPA, NP and OP were 80.1%‐108%, 81.3%‐109%, and 81.5%‐98.7%, respectively. Among the 60 urine samples, BPA was detected in 8 samples at the level of 0.297‐32.7ng/mL, NP was detected in 29 samples at the level of 1.69‐27.8 ng/mL, and OP was detected in 17 samples at the level of 0.407‐11.1 ng/mL. Conclusion The method is simple with high sensitivity and selectivity, and is suitable for the determination of BPA, NP, and OP in urine. As shown by our analysis , BPA, NP, and OP appear to be prevalent in human urine. This is particularly true for NP. The results from our study is therefore valuable for future studies to assess the exposure to BPA, NP, and OP in the general population.

Immunotoxicity of bisphenol A to Carassius auratus lymphocytes and macrophages following in vitro exposure

Bisphenol A （BPA） is the monomer component of polycarbonate plastics and classified as an endocrine disrupting chemical （EDC）. The reproductive toxicity of BPA has been extensively studied in mammals; however, relatively little information is available on the immunotoxic responses of fish to BPA. In this study, we investigated the effects of BPA on the immune functions of lymphocytes and macrophages in Carassius auratus. The effects of BPA were compared with those of two natural steroid hormones, estradiol and hydrocortisone. Proliferation of the two types of cells in response to PHA was measured using colorimetric MTT assay. Macrophage respiratory burst stimulated by Con A was measured using chemiluminescence assay. Results showed that BPA （0.054-5.4 mg/L）, estradiol （0.0002-2.0 mg/L） and hydrocortisone （5-50 mg/L） significantly induced Carassius auratus lymphocyte proliferation while higher doses of hydrocortisone （500-5000 mg/L） appeared to be inhibitory. BPA （0.005-50 mg/L）, estradiol （0.005-800 mg/L） and hydrocortisone （0.005-500 mg/L） markedly enhanced macrophage proliferation, whereas higher doses of BPA （500-1000 mg/L） appeared to inhibit cell proliferation. Furthermore, higher dosage of BPA （50 mg/L） and hydrocortisone （50 and 500 mg/L） suppressed the macrophages respiratory burst while estradiol is stimulative all the doses tested （0.05-500 mg/L）. In conclusion, BPA could have immunotoxicity to Carassius auratus and functional changes of lymphocyte and macrophage in Carassius auratus may be different between low and high dosages.

Effects of estradiol-17β and bisphenol A administered chronically to mice throughout pregnancy and lactation on the male pups＇ reproductive system

Aim： To assess the effect of estradiol-17β （E2） and bisphenol A （BPA） administered chronically by implanting a silicone tube throughout pregnancy and lactation on male pups＇ reproductive system in ICR mice. Methods： Female mice were implanted with a tube filled with 10 ng, 500 ng, 1 μg, or 10 μg of E2, or 100 μg or 5 mg of BPA, before mating. The tube was kept in the mice throughout pregnancy and lactation, until the pups had weaned at 4 weeks of age. During the period, E2 was released from the tube at 120 pg or 6, 12 or 120 ng/day, and BPA at 1.2 or 60 μg/day. Results： Most of the mice given 1 μg and 10 lag of E2 did not maintain their pregnancy. However, the other groups showed high rates of birth, more than 70%. At age of 4 weeks, the male pups were killed. Body weight and reproductive organ weights （testes, epididymides and accessory reproductive glands） in the treated groups did not differ from the control values, whereas the percentage of seminiferous tubules in the testis with mature spermatids was significantly lower in the groups given 10 ng and 500 ng of E2 and 5 mg of BPA than that in the control. Conclusion： Chronic exposure to E2 and BPA might disrupt spermatogenesis in male pups. （Asian JAndrol 2008 Mar; 10： 271-276）

Spatial distribution and deposition history of nonylphenol and bisphenol A in sediments from the Changjiang River(Yangtze River) Estuary and its adjacent East China Sea

Nonylphenol（NP） and bisphenol A（BPA） are endocrine disruptors causing harmful effects including feminization and carcinogenesis to various organisms,and consequently,their contamination in natural environment has received wide concerns.This study reports the distribution characteristics of NP and BPA in surface sediments and their deposition history based on a dated sediment core in the Changjiang River（Yangtze River） Estuary and its adjacent East China Sea.The contents of NP and BPA in surface sediments ranged from 1.56-35.8 and 0.72-13.2 ng/g（dry mass）,respectively,with high values recorded in the two mud zones,the Changjiang River Estuarine Mud Zone and the Zhejiang Coastal Mud Zone.High values in the Zhejiang Coastal Mud Zone suggest the possibility of long distance transport of both contaminants through the Changjiang riverine plume.The contents were not correlated with the distance from the pollution source,indicating other factors including particle deposition rate and sediment grain size obviously affecting the distribution pattern.NP was also detected in a sediment core at layers deposited from the year of 1971 to 2001 with contents of up to 20.9 ng/g（dry mass）.The deposition fluxes of NP varied from 0.68 to 17.9 ng/（cm^2 · a） with peaks and valleys reflecting the traces of economic development history in China during the previous three decades.BPA was detected at sediment layers deposited from 1973 to 2001 with contents of up to 3.66 ng/g.The fluxes of BPA varied from 0.62 to 3.13 ng/（cm^2 · a） showing a similar pattern as NP.The contents of NP and BPA also indicated potential risks on benthic organisms in the study area.

Effects of nonionic surfactant Triton X-100 on the laccase-catalyzed conversion of bisphenol A

The laccase-catalyzed conversion of bisphenol A （BPA） in aqueous solutions was studied in the absence and presence of nonionic surfactant Triton X-100. It was found that the addition of Triton X-100 into the reaction system increased the conversion of BPA, especially near the critical micelle concentration of Triton X-100. Also it was found that the stability of laccase was greatly improved in the presence of TritonX-100. Studies on the endogenous fluorescence emission of laccase indicated that there existed an interaction between Triton X-100 and laccase, which was beneficial to folding and stabilizating of laccase. The binding of Triton X-100 to the laccase surface also mitigated the inactivation effect caused by the free radicals and polymerization products. Under otherwise identical conditions, a lower dosage of laccase was needed for the higher conversion of BPA in the presence of Triton X-100.