水产品中多环芳烃菲的检测及生物降解的研究

多环芳烃是以非极性、中性分子形式存在的一类持久性有机污染物.菲是一种含有3个苯环的多环芳烃,广泛存在于煤焦油中,能够通过生物链行为在水体和水产品中积聚.选择菲作为主要研究对象,建立了一种从水产品中高效提取菲的方法,利用高效液相色谱(HPLC)法对市售花蛤、田螺中提取的菲进行分析检测,并且利用不同浓度的菲处理后进行富集度...     

两种方法检测食用油脂中的多环芳烃

分别建立同位素内标定量-QuEChERS净化-气相色谱-三重四级杆串联质谱法(方法一)和GPC自动净化-高效液相色谱-荧光检测法(方法二)两种方法,为检测食用油脂中欧盟优先控制的16种多环芳烃(EU15+1PAHs)提供了快速有效的方法。分别对104份食用油脂样品进行分析比较,对比两方法检测结果。结果表明:两方法均满足国内外对食品中PAHs检测的要求,方法一、方法二精密度实验RSD值分别小于5.4%、6.81%,平均加标回收率除个别外,分别在71.3%~111.6%、93.1%~119%范围内,RSD值分别小于5.0%、5.5%;标准曲线线性方程相关系数分别大于0.998、0.990,方法一定量限范围为0.23~0.50μg/kg,方法二定量限为0.9μg/kg、检出限为0.3μg/kg;英国食品化学分析实验室能力验证(FAPAS)盲样测定结果均达到规定检测结果;两方法对104份油样的两组检测结果无统计学差异,整体分析和分不同油种比较结果基本一致。结论:建立了针对食用油中EU15+1PAHs的分析方法,两方法均满足相应检测要求,且具有良好的准确性和实用性。     

两种方法检测食用油脂中的多环芳烃

分别建立同位素内标定量-QuEChERS净化-气相色谱-三重四级杆串联质谱法（方法一）和GPC自动净化-高效液相色谱-荧光检测法（方法二）两种方法,为检测食用油脂中欧盟优先控制的16种多环芳烃（EU15+1PAHs）提供了快速有效的方法。分别对104份食用油脂样品进行分析比较,对比两方法检测结果。结果表明:两方法均满足国内外对食品中PAHs检测的要求,方法一、方法二精密度实验RSD值分别小于5.4%、6.81%,平均加标回收率除个别外,分别在71.3%¹11.6%、93.1%¹19%范围内,RSD值分别小于5.0%、5.5%;标准曲线线性方程相关系数分别大于0.998、0.990,方法一定量限范围为0.23⁰.50μg/kg,方法二定量限为0.9μg/kg、检出限为0.3μg/kg;英国食品化学分析实验室能力验证（FAPAS）盲样测定结果均达到规定检测结果;两方法对104份油样的两组检测结果无统计学差异,整体分析和分不同油种比较结果基本一致。结论:建立了针对食用油中EU15+1PAHs的分析方法,两方法均满足相应检测要求,且具有良好的准确性和实用性。      

RT-PCR法检测贝类中的甲肝病毒的研究

在世界范围内,甲肝病毒是与食用贝类有关的主要传染性疾病之一。由于贝类中含有PCR抑制剂以及病毒富集过程中病毒的回收率低,阻碍了天然污染的贝类中HAV的PCR检测。研究中建立了一种经苷氨酸缓冲液洗涤,2次PEG沉降富集病毒,然后进行RNA提取和RT-PCR对贝类中的甲肝病毒进行检测的方法。经比较,采用小体系肠道样品检测比采用全贝检测的富集效果更佳,并比较了PEG8000和PEG6000对病毒富集的效果,回收率分别为13.5%和7.6%,此方法可有效地降低PCR抑制剂的影响,最低检测限可达10个TCID50/1.5 g。     

混菌发酵降解稻草产糖的研究

选用实验室保藏的平菇、里氏木霉和青霉进行了混菌发酵降解稻草产糖的研究.对发酵产糖培养基的稻草添加量、麸皮添加量、混合发酵时间、发酵温度和起始pH值5个方面进行了发酵条件的优化,得到最佳条件为稻草添加量6%,麸皮添加量3%,先接入平菇28℃发酵7d,再接入里氏木霉和青霉32℃发酵3d,起始pH值为6.经混菌发酵条件优化后稻草产糖量可达19.52mg/mL,是优化前的1.28倍.并对发酵前后的稻草秸秆进行电镜扫描分析基质表观结构的变化,结果表明:混菌发酵能较好地破坏并降解稻草秸秆的木质素、纤维素和半纤维素结构.     

含螺旋藻产品中多环芳烃污染状况研究

目的 建立气相色谱-串联质谱法(gas chromatography-mass spectrometry, GC-MS/MS)测定含螺旋藻产品中多环芳烃残留量的方法, 并以此法探究市售含螺旋藻产品中以苯并(a)蒽、?、苯并(b)荧蒽和苯并(a)芘为代表的多环芳烃污染状况。方法 样品采用正己烷提取, 经QuEChERS净化, 选择DB-5 MS毛细管色谱柱, 在多反应监测(multiple reaction monitoring, MRM)模式下采用基质匹配外标法定量。采用4种多环芳烃化合物(polycyclic aromatic hydrocarbons, PAH)总量(PAH4)和苯并(a)芘进行双指标分析, 并结合摄入量对市售含螺旋藻产品中多环芳烃污染情况进行分析。结果 4种化合物在1~32 μg/L的范围内具有良好的线性关系, 相关系数r2>0.995, 方法定量限4 μg/kg, 平均回收率为64.1%~102%, 相对标准偏差(relative standard deviations, RSD)为2.2%~6.4% (n=6)。75个受试样本的多环芳烃检出率为76%, 检出的4种多环芳烃含量范围为4.1~916.0 μg/kg。在苯并(a)芘含量大于50 μg/kg时, 苯并(a)芘含量与PAH4含量之间呈现明显的正相关, 但在低于50 μg/kg时, 两者未显示出相关性。结论 建立的方法准确度高, 灵敏度好, 适用于含螺旋藻产品中多环芳烃的检测。实际样品的测定结果显示, 市售含螺旋藻产品中存在高水平多环芳烃污染的情况, 可能对服用者产生安全风险。样本中苯并(a)芘与PAH4总量之间存在一定相关性, 在高污染水平两者相关性趋明显, 在低污染水平苯并(a)芘不宜作为螺旋藻中多环芳烃污染的唯一指标。建议食品安全相关部门应加强风险防控, 制定合理的控制规范、设立恰当的指标限量。     

气质联用法检测玉米油中的16种多环芳烃

采用SPE固相萃取柱净化,利用气质联用仪以外标法定量检测玉米油中16种多环芳烃(PAHs)。结果表明:经NIST谱库检索,能够确认16种PAHs,并能检测其在玉米油中的质量浓度。样品加标回收率检测中,加标量1μg/L时,16种PAHs回收率为74.6%~89.8%,RSD为4.6%~9.2%;加标量10μg/L时,16种PAHs回收率为82.3%~97.9%,RSD为4.8%~9.8%。     

GC-MS用于测定造纸废水中的多环芳烃

研究了不同前处理手段和测试条件对气相色谱质谱联用仪(GC-MS)测定造纸废水中多环芳烃(PAHs)持久性有机污染物的影响。经对比,最优测试条件为选用DB-5作为GC-MS毛细管色谱柱,选用二氯甲烷作为萃取剂,萃取时间30 min,同时加入1.0 g NaCl作为盐析剂,机械振荡20 min。     

流式细胞术在双壳贝类免疫研究中的应用

双壳贝类作为重要的水产品经济物种和生态指示物种在全球范围内得到广泛养殖,由于其具有重要的经济价值及在生态毒理学中的环境指示作用,其免疫能力逐渐受到越来越多的关注。双壳贝类先天免疫的主要参与者是血细胞,血细胞参与细胞凋亡、吞噬、抗氧化和免疫黏附等细胞免疫,同时还能分泌大量的溶菌酶、细胞因子、补体系统、抗菌肽等参与双壳贝类的体液免疫,因此,血细胞参数如细胞活力、吞噬能力、粘附能力、总循环血细胞计数、过氧化物酶活性等的检测成为探索双壳贝类免疫研究的重要内容。流式细胞术(flow cytometry, FCM)以其高效、快速、高灵敏度、客观性强等特点成为双壳贝类免疫功能研究的重要手段。本文结合国内外近年来关于流式细胞术在双壳贝类免疫研究中的应用,介绍了FCM的发展历史、双壳贝类免疫学的研究进展及FCM在双壳贝类免疫研究的应用,同时,讨论了流式细胞术在进行贝类总血细胞计数、细胞分类、吞噬作用、细胞凋亡等免疫参数的检测中的应用进展 。提出流式细胞术在处理和检测样品中凾待解决的问题及对未来流式细胞术作为贝类免疫参数检测技术发展展望,以期流式细胞术在未来贝类免疫学的进一步研究中发挥重要作用。     

混菌发酵水稻秸秆生产柠檬酸工艺的研究

研究了黄孢原毛平革菌、里氏木霉和黑曲霉共同发酵生产柠檬酸。首先以水稻秸秆中木质素、半纤维素和纤维素的降解率为参考指标,通过单因素试验和多因素正交试验考察黄孢原毛平革菌和里氏木霉对水稻秸秆的降解情况,最佳的结果:初始pH为4.0,黄孢原毛平革菌和里氏木霉的比例为1∶5,黄孢原毛平革菌和里氏木霉的复合接种量为18%,最佳的发酵降解时间140h。然后接种黑曲霉,以柠檬酸的产量为参考指标,通过单因素试验和多因素正交试验考察黑曲霉发酵情况,最佳结果:初始pH为4.0,黑曲霉的接种量为15%,最佳的发酵降解时间140h,柠檬酸的产量达到79.83g·L~(-1)。     

Case study of the relationship between fungi and bacteria associated with high-molecular-weight polycyclic aromatic hydrocarbon degradation

Although bacteria play dominant roles in microbial bioremediation, few of them have been reported that were capable of utilizing high-molecular-weight (HMW) organic pollutants as their sole sources of carbon and energy. However, many soil fungi can metabolize those of pollutants, although they rarely complete mineralization. In this paper, we investigated the dynamic relationship between fungi and bacteria associated with degradation of HMW-polycyclic aromatic hydrocarbons (PAHs). Artificial fungal-bacterial mixed cultures were constructed to simulate the environment of actual polluted sites. Four bacterial strains and seven fungal strains were isolated that related to the removal of phenanthrene, fluoranthene and pyrene in the soil. Furthermore, these strains were used to create mixed culture of bacteria (Bact-mix), mixed culture of fungi (Fung-mix), fungal-bacterial co-cultures (Fung-Bact), respectively. The maximal pyrene removal rate (67%, 28days) was observed in the Fung-Bact, compared with cultures of Fung-mix (39%) and Bact-mix (56%). The same tendency was also indicated in the degradation of phenanthrene and fluoranthene. In addition, a dynamic relationship during the degradation process between fungi and bacteria was monitored through using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method.     

Effect of slow desorption on the kinetics of biodegradation of polycyclic aromatic hydrocarbons

The bioavailability to bacteria of 14C-labeled polycyclic aromatic hydrocarbons (PAHs) sorbed onto lake sediments was assessed using a mathematical model and three experimental series. The experiments were performed under similar conditions and included: (1) abiotic desorption of PAHs from sediments by Tenax extraction, (2) mineralization of dissolved PAHs with no sediment present, and (3) mineralization of PAHs sorbed onto sediments. Results obtained from the first two series were used to obtain the parameter values for the model, and the experimental results of the third series were compared to model results. We found that microorganisms were able to promote desorption of the more-labile fractions, but were unable to increase the desorption rate of the slow- and very slow-desorbing fractions. Also, our model predictions indicate that, after very long contact times, and in the concurrence of biodegradation, sorbed PAHs remain not under equilibrium conditions, but rather in a steady state. The net rates of PAH desorption from the three sediment domains considered (fast, slow, and very slow) become similar, and the ratio between the aqueous and the sediment concentration remains constant with time.     

焙炒条件对芝麻油中多环芳烃含量的影响

对芝麻进行不同条件焙炒实验,榨取芝麻油,之后对不同焙炒条件下芝麻油中多环芳烃含量进行检测分析。结果表明:随着焙炒时间的延长、焙炒温度的升高,芝麻油中B[a]P、PAH4、PAH16的含量都呈现明显上升趋势;对照国标GB 2716—2005及欧盟No835/2011号法规关于B[a]P和PAH4的限量,芝麻籽的合理焙炒时间不宜超过30 min,焙炒温度不宜超过200℃;焙炒时间为30 min的条件下,焙炒温度在200~240℃之间时,有利于3环物的积累,而焙炒温度达到260℃时,则有利于4环物及重质多环芳烃的积累。     

Cyclodextrin enhanced biodegradation of polycyclic aromatic hydrocarbons and phenols in contaminated soil slurries

This work aimed to evaluate the relative contribution of soil catabolic activity, contaminant bioaccessibility, and nutrient levels on the biodegradation of field-aged polycyclic aromatic hydrocarbons and phenolic compounds in three municipal gas plant site soils. Extents of biodegradation achieved, in 6 week-long soil slurry assays, under the following conditions were compared: (i) with inoculation of catabolically active PAH and phenol-degrading microorganisms, (ii) with and without hydroxypropyl-beta-cyclodextrin supplementation (HPCD; 100 g L(-1)), and finally (iii) with the provision of additional inorganic nutrients in combination with HPCD. Results indicated no significant (p < 0.05) differences between biodegradation endpoints attained in treatments inoculated with catabolically active microorganisms as compared with the uninoculated control. Amendments with HPCD significantly (p < 0.05) lowered biodegradation endpoints for most PAHs and phenolic compounds. Only in one soil did the combination of HPCD and nutrients consistently achieve better bioremediation endpoints with respect to the HPCD-only treatments. Thus, for most compounds, biodegradation was not limited by the catabolic activity of the indigenous microorganisms but rather by processes resulting in limited availability of contaminants to degraders. It is therefore suggested that the bioremediation of PAH and phenol impacted soils could be enhanced through HPCD amendments. In addition, the biodegradability of in situ and spiked (deuterated analogues) PAHs following 120 days aging of the soils suggested that this contact time was not sufficient to obtain similar partitions to that observed for field-aged contaminants; with the spiked compounds being significantly (p < 0.05) more available for biodegradation.     

Effect of interface fertilization on biodegradation of polycyclic aromatic hydrocarbons present in nonaqueous-phase liquids

The main goal of this study was to use an oleophilic biostimulant (S-200) to target possible nutritional limitations for biodegradation of polycyclic aromatic hydrocarbons (PAHs) at the interface between nonaqueous-phase liquids (NAPLs) and the water phase. Biodegradation of PAHs present in fuel-containing NAPLs was slow and followed zero-order kinetics, indicating bioavailability restrictions. The biostimulant enhanced the biodegradation, producing logistic (S-shaped) kinetics and 10-fold increases in the rate of mineralization of phenanthrene, fluoranthene, and pyrene. Chemical analysis of residual fuel oil also evidenced an enhanced biodegradation of the alkyl-PAHs and n-alkanes. The enhancement was not the result of an increase in the rate of partitioning of PAHs into the aqueous phase, nor was it caused by the compensation of any nutritional deficiency in the medium. We suggest that biodegradation of PAH by bacteria attached to NAPLs can be limited by nutrient availability due to the simultaneous consumption of NAPL components, but this limitation can be overcome by interface fertilization.     

Assessment of the dietary habits and polycyclic aromatic hydrocarbon exposure in primary school children

Thirty Italian children, 7–9 year aged, living in Naples were investigated on their dietary habits and on polycyclic aromatic hydrocarbon (PAH) exposure by a food diary-questionnaire and one week duplicate diet sample analyses. Daily total food consumption mean value was 632 ± 215 g day^?1, median value 613 g day^?1. The daily energy intake and the diet composition meanly agreed with the official guidelines for the Italian children. Sixteen PAHs were simultaneously detected and, according to the European Food Safety Authority (EFSA) approach, benzo[a]pyrene; benzo[a]pyrene + chrysene (PAH2); PAH2 + benz[a]anthracene + benzo[b]fluoranthene (PAH4); PAH4 + benzo[k]fluoranthene + benzo[ghi]perylene + dibenz[a, h]anthracene + indeno[1,2,3-cd]pyrene (PAH8) were considered in evaluating the children's dietary exposure to PAHs. The benzo[a]pyrene (BaP) median concentrations in foods varied from 0.06 to 0.33 µg kg^?1. Only three samples of cooked foods (one fish and two meat samples) exceeded legal limits fixed by the European Union for BaP. Daily median intakes of benzo[a]pyrene, PAH2, PAH4, and PAH8 were 153; 318; 990; 1776 ng day^?1; their median exposure values were 5; 10; 28; 54 ng kg^?1 bw day^?1. The Margins of Exposure (MOEs) in median consumers agreed with the EFSA safety values except for PAH8.     

Impact of vegetation on sedimentary organic matter composition and polycyclic aromatic hydrocarbon attenuation

Results from natural and engineered phytoremediation systems provide strong evidencethatvegetated soils mitigate polycyclic aromatic hydrocarbon (PAH) contamination. However, the mechanisms by which PAH mitigation occurs and the impact of plant organic matter on PAH attenuation remain unclear. This study assessed the impact of plant organic matter on PAH attenuation in labile and refractory sediments fractions from a petroleum distillate waste pit that has naturally revegetated. Samples were collected in distinct zones of barren and vegetated areas to assess changes to organic matter composition and PAH content as vegetation colonized and became established in the waste pit. Sediments were fractionated into bulk sediment and humin fractions and analyzed for organic matter composition by isotope ratio mass spectrometry (delta (13)C), 13C nuclear magnetic resonance (13C NMR), delta 14C AMS (accelerator mass spectrometry), and percent organic carbon (%TOC). Gas chromatography mass spectrometry (GC/ MS) of lipid extracts of SOM fractions provided data for PAH distribution histograms, compound weathering ratios, and alkylated and nonalkylated PAH concentrations. Inputs of biogenic plant carbon, PAH weathering, and declines in PAH concentrations are most evidentfor vegetated SOM fractions, particularly humin fractions. Sequestered PAH metabolites were also observed in vegetated humin. These results show that plant organic matter does impact PAH attenuation in both labile and refractory fractions of petroleum distillate waste.