苯并(a)芘及其代谢产物的连续降解研究

在以驯化过的芽孢杆菌(BA-07)降解BaP的过程中,鉴定出2个BaP的未开环代谢产物顺式-4,5-二氢-4,5-二醇-BaP(cis-BP4,5-dihydrodiol)和顺式-7,8-二氢-7,8-二醇-BaP(cis-BP7,8-dihydrodiol).由于该产物对微生物有一定毒性,所以难于进一步降解.为提高BaP降解的同时,降低cis-BP4,5-dihydrodiol和cis-BP7,8-dihydrodiol的累积,对2种降解方法(即单纯用BA07降解和运用高锰酸钾与BA-07耦合的方法降解)进行了比较,并且优化了连续降解的参数.结果表明,①对BaP及其代谢产物的连续降解,化学氧化与微生物耦合(高锰酸钾与BA-07)的降解效果明显好于单纯利用微生物(细菌BA-07)的降解;②在同一时间取样,cis-BP4,5-dihydrodiol的残留率均高于cis-BP7,8-dihydrodiol;③当BaP的浓度为40μg/mL,培养基的最佳pH为7.0,以琥珀酸钠为共代谢底物,可以显著提高BaP降解率,降低cis-BP 4,5-dihydrodiol和cis-BP7,8-dihydrodiol的累积.同时提出了化学氧化与微生物协同的方法可以有效促进环境中持久有机污染物的连续降解.     

六株真菌对土壤中芘和苯并芘的降解及其动力学

研究了6株真菌对土壤中芘和苯并芘(BaP)的降解动态,用Michaelis-Menton和Monod动力学模型对结果进行拟合.结果表明,6株真菌对芘和BaP的降解速率有显著性差异,降解率相差不大.产黄青霉(Penicillium chrysogenum,SF04),在42d内对BaP的降解能力最强,可达71.31%,对芘的降解能力相对最弱.镰刀菌(Fusariumsp.,SF11),黑曲霉(Aspergillusniger,SF05),木霉(Trichodermasp.,SF02)和毛霉(Mucorsp.,SF06)42d对芘的降解率分别为86.22%,86.18%,85.41%,85.04%,对BaP的降解率分别为71.11%,69.44%,69.05%,69.72%.木霉(Trichodermasp.,SF02)和毛霉(Mucorsp.,SF06)对芘和BaP的降解速率均很快.     

Ploidy-, gender-, and dose-dependent alteration of selected biomarkers in Clarias gariepinus treated with benzo[a]pyrene

Naturally-occurring and artificially-induced polyploids have been documented in various fish species but to date no comparison has been reported of the impacts of ploidy on fish biomarker responses to organic pollutants. This study describes effects of ploidy, gender, and dose on biliary fluorescent aromatic compound (FAC) concentrations, hepatic ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST) activities in one of the most commonly cultured warm-water species, the African catfish Clarias gariepinus. Recently matured male and female diploid and triploid fish were intraperitoneally (i.p.) injected with 0, 5 or 25 mg/kg benzo[a]pyrene (BaP) and liver and gallbladder were sampled 48 hr later. No significant differences were found between ploidies in bile concentrations of 7,8 dihydrodiolbenzo[a]pyrene (7,8D BaP), 1-hydroxybenzo[a]pyrene (1-OH BaP) or 3-hydroxybenzo[a]pyrene (3-OH BaP). However, concentrations of the biliary FACs did differ between males and females at different dose of injection with generally higher concentrations in females at the low dose of BaP and higher concentrations in males at the higher BaP concentration. Hepatic EROD activity did not exhibit gender-dependent difference, whereas it was significantly higher in triploids than diploids. GST activities were not significantly influenced by any of the tested factors. This work advanced our understanding of the role of ploidy, gender, and dose in biotransformation of pollutants in fish.     

3株细菌对土壤中芘和苯并芘的降解及其动力学

研究了3株多环芳烃(PAHs)高效降解菌对土壤中芘和苯并芘(BaP)的降解动态,用Michaelis-Menton和Monod动力学模型对结果进行拟合.结果表明,3株细菌对芘和BaP的降解率有显著性差异.芽孢杆菌(Bacillus sp.SB02)42 d对芘和BaP的降解率均最高.当土壤中芘和BaP的初始浓度为50　mg/kg时,芽孢杆菌(Bacillus sp. SB02)、动胶杆菌(Zoogloea sp. SB09)、黄杆菌(Flavobacterium sp. SB10)42 d对芘的降解率分别为42.69%、32.88%、25.07%, 对BaP的降解率分别为33.04%、25.39％、22.02%.3株细菌对芘和BaP的降解速率也存在显著性差异.芽孢杆菌(Bacillus sp., SB02)最快,1周可降解20.88％芘和12.6%的BaP,动胶杆菌(Zoogloea sp.SB09)次之,黄杆菌(Flavobacterium sp.SB10)降解速率最慢.     

Relation of hepatic EROD activity and CYP1A level in Sebastiscus marmoratus exposed to benzo[a]pyrene

This study was designed to investigate the in vivo effects of benzo[a]pyrene (BaP) on hepatic ethoxyresorufin-O-deethylase (EROD) activity and its correlation with cytochrome P450 1A (CYP1A) protein levels in Sebastiscus marmoratus, which were exposed through a water column to BaP (10, 100, 1000 ng/L, respectively) or were treated with intraperitoneal injections of BaP (0.5, 1, 5, 10 mg/kg, respectively) every 7 d. The results showed that after 25 d of waterborne exposure to 1000 ng/L BaP, fish hepatic CYP1A levels and EROD activity were significantly induced. In contrast, EROD activity was not altered 7 d after second ip injections, whereas, CYP1A protein levels were increased. Dose-dependent increase of biliary BaP metabolites demonstrated that the catalytic activity of CYP1A was induced by treatment with BaP. The lowest observable effect concentration with regard to biliary BaP metabolites (100 ng/L) was much lower than that with reference to EROD activity (1000 ng/L). The results suggest that biliary polycyclic aromatic hydrocarbon (PAH) metabolites were shown to better reflect the contamination gradients of PAHs than EROD activity. It appeared to be necessary to measure CYP1A protein levels to complement the EROD activity in relevant toxicological assessments.     

Relation of hepatic EROD activity and cytochrome P4501A level in Sebastiscus marmoratus exposed to benzo[a]pyrene

This study was designed to investigate the in vivo effects of benzo[a]pyrene （BaP） on hepatic ethoxyresorufin-O-deethylase （EROD） activity and its correlation with cytochrome P4501A （CYP1A） protein levels in Sebastiscus marmoratus, which were exposed through a water column to BaP （10, 100, 1000 ng/L, respectively） or were treated with intraperitoneal injections of BaP （0.5, 1, 5, 10 mg/kg, respectively） every 7 d. The results showed that after 25 d of waterborne exposure to 1000 ng/L BaP, fish hepatic CYP1A levels and EROD activity were significantly induced. In contrast, EROD activity was not altered 7 d after second intraperitoneal injections, whereas, CYP1A protein levels were increased. Dose-dependent increase of biliary BaP metabolites demonstrated that the catalytic activity of CYP1A was induced by treatment with BaP. The lowest observable effect concentration with regard to biliary BaP metabolites （100 ng/L） was much lower than that with reference to EROD activity （1000 ng/L）. The results suggest that biliary polycyclic aromatic hydrocarbon （PAH） metabolites were shown to better reflect the contamination gradients of PAHs than EROD activity. It appeared to be necessary to measure CYP1A protein levels to complement the EROD activity in relevant toxicological assessments.     

Isolation of marine benzo[a]pyrene-degrading Ochrobactrum sp. BAP5 and proteins characterization

A bacterial strain BAP5 with a relatively high degradation ability of benzo[a]pyrene (BaP) was isolated from marine sediments of Xiamen Western Sea, China and identified as Ochrobactrum sp. according to 16S rRNA gene sequence as well as Biolog microbial identification system. Strain BAP5 could grow in mineral salt medium with 50 mg/L of BaP and degrade about 20% BaP after 30 d of incubation. Ochrobactrum sp. BAP5 was able to utilize other polycyclic aromatic hydrocarbons (PAHs) (such as phenanthrene, pyrene and fluoranthene) as the sole carbon source and energy source, suggesting its potential application in PAHs bioremediation. The profile of total soluble protein from Ochrobactrum sp. BAP5 was also investigated. Some over- and special-expressed proteins of strain BAP5 when incubated with the presence of BaP were detected by two-dimensional polyacrylamide gel electrophoresis, and found to be related with PAHs metabolism, DNA translation, and energy production based on peptide fingerprint analysis through matrix-assisted laser desorption/ionization-time of flight mass spectrometry.     

PBPK模型在苯并[α]芘健康风险评估中的应用探讨

苯并[α]芘〔benzo[α]pyrene,BaP〕是环境中广泛存在的一种致癌多环芳烃,带来的健康风险受到普遍关注. 基于生理的药代动力学(physiologically based pharmacokinetic, PBPK)模型是一种预测污染物在生物体内部剂量的数学模型,近年来在健康风险评估中应用广泛. 本文介绍了BaP对生物体的健康危害,概述了BaP的PBPK模型研究进展,指出了BaP人体PBPK模型存在BaP及代谢物的代谢机理尚未完全明确、代谢参数可靠性不高、模型还需继续完善等问题,并探讨了PBPK模型在BaP健康风险评估中的应用. 一方面,PBPK模型在阐明内暴露监测结果及补充完善污染物在人体内的代谢机理方面具有明显优势,基于PBPK模型分析完善了BaP生物标志物3-羟基苯并[α]芘在肾小管重吸收的肾脏排泄机制;另一方面,PBPK模型作为外推工具,通过种间外推可以量化污染物的种间药代动力学差异,减小动物健康剂量水平外推至人体基准值的不确定性;通过体外到体内的外推可以关联内外暴露剂量,利用反剂量学推导人体健康基准值. 这两种外推方法的应用均可以提高人体健康基准值推导的科学性、准确性. 并以BaP为例剖析了PBPK模型不确定性来源,提出了提高模型精确性的方法. 最后,为了进一步推动完善BaP的人体健康风险评估方法体系,本文探讨总结了3个重点研究方向:一是探索PBPK模型应用于BaP健康风险评估的方法体系;二是探索可靠性更高的BaP健康风险评估概率模型;三是开展BaP的生物标志物用于人体健康风险评估可行性研究.      

Biodegradation of benzo[a]pyrene in soil by Mucor sp. SF06 and Bacillus sp. SB02 co-immobilized on vermiculite

Two indigenous microorganisms, Bacillus sp. SB02 and Mucor sp. SF06, capable of degrading polycyclic aromatic hydrocarbons （PAHs） were co-immobilized on vermiculite by physical adsorption and used to degrade benzo[a] pyrene （BaP）. The characteristics of BaP degradation by both free and co-immobilized microorganism were then investigated and compared. The removal rate using the immobilized bacterial-fungal mixed consortium was higher than that of the freely mobile mixed consortium. 95.3% of BaP was degraded using the co-immobilized system within 42 d, which was remarkably higher than the removal rate of that by the free strains. The optimal amount of inoculated co-immobilized system for BaP degradation was 2%. The immobilized bacterial-fungal mixed consortium also showed better water stability than the free strains. Kinetics of BaP biodegradation by co-immobilized SF06 and SB02 were also studied. The results demonstrated that BaP degradation could be well described by a zero-order reaction rate equation when the initial BaP concentration was in the range of 10--200 mg/kg. The scanning electronic microscope （SEM） analysis showed that the co-immobilized microstructure was suitable for the growth of SF06 and SB02. The mass transmission process of co-immobilized system in soil is discussed. The results demonstrate the potential for employing the bacterial-fungal mixed consortium, co-immobilized on vermiculite, for in situ bioremediation of BaP.     

Isolation of marine benzo[a]pyrene-degrading Ochrobactrum sp. BAP5 and proteins characterization

A bacterial strain BAP5 with a relatively high degradation ability of benzo[a]pyrene (BaP) was isolated from marine sediments of Xiamen Western Sea, China and identified as Ochrobactrum sp. according to 16S rRNA gene sequence as well as Biolog microbial identification system. Strain BAP5 could grow in mineral salt medium with 50 mg/L of BaP and degrade about 20% BaP after 30 d of incubation. Ochrobactrum sp. BAP5 was able to utilize other polycyclic aromatic hydrocarbons (PAHs) (such as phenanthrene, pyrene and fluoranthene) as the sole carbon source and energy source, suggesting its potential application in PAHs bioremediation. The profile of total soluble protein from Ochrobactrum sp. BAP5 was also investigated. Some over- and special-expressed proteins of strain BAP5 when incubated with the presence of BaP were detected by two-dimensional polyacrylamide gel electrophoresis, and found to be related with PAHs metabolism, DNA translation, and energy production based on peptide fingerprint analysis through matrix-assisted laser desorption/ionization-time of flight mass spectrometry.     

异烟酸铜磁力搅拌微固相萃取-气相色谱法测定土壤中多环芳烃

建立了膜保护异烟酸铜微固相萃取的样品前处理方法,并采用气相色谱氢火焰离子化检测器对土壤中的痕量荧蒽(Flt)、苯并［b］荧蒽(BbF)、苯并［k］荧蒽(BkF)、苯并［a］芘(BaP)进行了测定. 考察了水温、萃取时间和超声洗脱时间等对萃取效果的影响. 结果表明:在最佳试验条件下,Flt的检出限为1.0 ng/g;BbF,BkF和BaP的检出限为2.5 ng/g. Flt的线性范围为2.5～500.0 ng/g;BbF,BkF和BaP的线性范围均为12.5～500.0 ng/g. 相对标准偏差(RSD)为4.4%～13.7%(n9). 采用该方法分析了2种实际土壤中的4种多环芳烃,回收率为34%～90%.      

几种芳香化合物对苯并芘在泥浆反应器中降解的影响

苯并芘在土壤中难于被生物降解,其降解方式通常以共代谢方式进行.本研究考查了几种多环芳烃及2种单环芳香化合物对苯并芘降解的影响.先把几种芳香化合物投入到供试无污染土壤中进行3d的预培养,然后向土壤中加入苯并芘并使土壤在三角瓶内形成泥浆系统,放在摇床上培养.42d的实验表明,用菲对土壤进行预处Ζ理消除了苯并芘的降解滞后期,并提高了苯并芘的降解率.蒽、芘未能改变苯并芘的降解模式,而苯并蒽则相对抑制了苯并芘的降解.水杨酸和邻苯二甲酸同样消除了苯并芘降解的滞后阶段,且促进了苯并芘的降解,但质量差别未对苯并芘的降解产生影响.     

Combined effect of tributyltin and benzo[a] pyrene on the levels of sex hormone and vitellogenin in female Sebastiscus marmoratus

Tributyltin（TBT）, an organometal used as an antifouling biocide, has been reported to induce masculinization of fish. Benzo [a]pyrene （BaP）, a widespread carcinogenic polycyclic aromatic hydrocarbon, has been reported that its microsomal metabolites can produce an estrogenic response when tested in vitro. This study was therefore designed to examine the potential in vivo influence of TBT, BaP and their mixture on sex hormone levels in serum of Sebastiscus marmoratus, which were given 2 separate intraperitoneally （ip） injections（a single injection every 7 d） of TBT（0.5, 1, 5 and 10 mg/kg）, BaP（0.5, 1, 5 and 10 mg/kg）, or both in combination（0.5, 1, 5 and 10 mg/kg）; control fish received olive oil vehicle only. Six days after the 2nd injection, serum samples were collected and analyzed for sex hormone levels and alkali labile protein phosphorus （ALPP）, which is related to the yolk precursor protein vitellogenin. The pollutants at all doses significantly reduced serum testosterone, estradiol and ALPP content after 2 injections compared with the corresponding controls. The reduction of the estradiol levels should be response for the decrease of the vitellogenin levels. The results in the present study suggested that aromatase seems not the major target acted by TBT and BaP in fish. This study demonstrated that TBT or BaP exposure both inhibit the reproductive potential in female Sebastiscus marmoratus. Combined effect of TBT and BaP on the serum testosterone, estradiol and ALPP was not antagonism from the anticipation.     

苯并[a]芘对赤子爱胜蚓线粒体编码基因表达影响研究

根据ISO 11268-1:1993方法,完成了土壤中苯并[a]芘对赤子爱胜蚓(Eisenia fetida)的人工污染模拟实验.并采用Clontech PCR-SelectTM cDNA Subtration Kit构建了污染组和对照组蚯蚓之间的抑制消减文库.经测序和比对分析,在苯并[a]芘诱导上调文库中发现5个线粒体DNA(mtDNA)编码的基因,且在上调文库中具有较高的频率.它们分别为:细胞色素c氧化酶亚基Ⅰ、Ⅱ、Ⅲ,NADH氢脱氢酶亚基1,ATP合成酶亚基.研究表明,土壤中苯并[a]芘污染改变了蚯蚓线粒体基因组的表达水平,线粒体基因组表达异常是多环芳烃污染胁迫的重要分子生物标记物.     

室内空气中苯并[a]芘的健康限值研究

应用健康风险评估方法,基于中国人群暴露参数特征推导我国不同人群的室内苯并[a]芘（Benzo[a]pyrene,BaP）浓度限值.并通过文献调研收集我国室内空气中BaP浓度,运用蒙特卡洛方法计算不同人群的BaP暴露致癌风险,探讨限值的可达性.研究发现,基于具有全国代表性人群暴露特征推导所得的BaP限值的平均值±标准偏差为（1.38±0.32）ng/m³,与我国现行《室内空气质量标准》（GB18883-2002）中的BaP限值相近.基于城市男性、女性暴露特征推导的健康限值分别为1.34ng/m³和1.40ng/m³,基于农村男性、女性暴露特征推导的限值分别为1.35ng/m³和1.41ng/m³.基于低年龄人群暴露特征推导的限值要低于高年龄段人群限值.我国大部分室内空气BaP实际监测浓度高于本研究推导出的健康限值,建议持续加强室内清洁能源使用和控烟等措施,减少BaP室内暴露风险.     

尿液中多环芳烃羟基代谢产物分析方法研究

通过实验建立了"酶水解-固相萃取-HPLC 荧光检测"尿液中多环芳烃羟基代谢产物1-羟基芘,9-羟基苯并[a]芘和3-羟基苯并[a]芘的分析方法,研究了3种代谢产物在不同保存温度下的稳定性,并通过对200个实际尿液的测定初步验证了该方法的可行性。该方法回收率为70%～85%,最低检出限为0 02～0 05μg L。-20℃保存的尿液样品及尿液提取液中3种化合物在1个月内降解了10%～36%,提取液比尿液的稳定性稍好,保存温度越高稳定性越差。      

基于DALYs的北京市大气PM2.5载带苯并[a]芘疾病负旦研究

苯并[a]芘(BaP)是一类兼具强致癌性和非致癌毒性的物质,可随PM_(2.5)经呼吸途径进入人体而威胁健康.本文采集2016年北京城区监测点PM_(2.5)样品并采用气相色谱质谱联用仪测定其载带BaP浓度.通过BaP的流行病学及动物毒理学数据的检索和分析,确定BaP呼吸暴露的致癌和非致癌毒效应评价终点及其剂量效应关系.运用伤残调整生命年(DALYs)指标估算了呼吸途径人群PM_(2.5)载带BaP暴露导致的疾病负担.结果显示北京市BaP导致总疾病负担为431.36 DALYs·a~(-1),每千人DALYs为0.03 a~(-1).其中非致癌效应的疾病负担为1.98 DALYs·a~(-1),致癌效应为429.39 DALYs·a~(-1).不同毒效应的疾病负担排序为:癌症(99.54%)发育毒性(0.41%)生殖毒性(0.04%).不同季节的疾病负担贡献差异较大.北京市BaP暴露导致疾病负担的主要贡献季节为冬季,疾病负担贡献的顺序为冬季(88.01%)秋季(4.91%)春季(4.34%)夏季(2.74%).     

天津市环境空气中苯并[a]芘的变化趋势

分析了天津市环境空气中苯并[a]芘污染的程度及变化趋势,结果表明,天津市大气中苯并[a]芘污染成逐年下降趋势,同一年中苯并[a]芘浓度是非采暖期低于采暖期,月均值变化规律是夏季<春、秋季<冬季,天津市环境空气中苯并[a]芘污染总体来说处于较低的水平。     

真菌对土壤中苯并[a]芘的共代谢降解

研究了模拟生物泥浆法修复多环芳烃污染土壤.选择了几种从石油污染土壤中分离出来的真菌,研究它们对土壤内苯并[a]芘的降解,并研究了土壤内共存底物:菲、芘、邻苯二甲酸对苯并[a]芘降解的影响,及其之间的共代谢过程.结果表明,芘可以促进镰刀菌、毛霉对苯并[a]芘的降解,并认为这是共代谢作用的结果;菲也可以促进镰刀菌对苯并[a]芘的降解,但抑制了毛霉和青霉对苯并[a]芘的降解;而邻苯二甲酸对青霉和毛霉降解苯并[a]芘的过程均有抑制作用.      

多环芳烃污染土壤的生物泥浆法修复

通过小型泥浆反应器的运行,确定了生物泥浆法修复多环芳烃污染土壤的温度、水土比和通气量参数.采用2:1的水土比,控制温度、通气量分别为20℃～25℃,60L/h可以达到较好的修复效果.用从污染土壤中分离出的真菌在纯培养条件下对多环芳烃进行降解,经34d的培养,镰刀菌对芘和苯并蒽的降解率为90%和33.3%,毛霉可以分别降解81.5%和49.2%,青霉可以分别降解52%和46%.