牡蛎中多组分多环芳烃的光动力降解研究

目的:寻求一种高效、经济、安全可靠的新型食品中有机污染物降解方法。方法:通过比较三种光敏剂（姜黄素、核黄素、金丝桃素）对牡蛎肉外观品质的影响以及光动力对水溶液中多环芳烃的降解效果,对其进行工艺优化,在最优条件下探究光动力对牡蛎中多环芳烃的降解作用。结果:当光敏剂浓度为10 μmol/L时,富集量高达89.68%~92.22%,且牡蛎肉为正常的奶白色,并未发生变化。而当浓度为20 μmol/L时,富集量仅为71.90%~78.62%,牡蛎肉颜色发生肉眼可见的由白色到黄色的变化。与核黄素和金丝桃素相比,姜黄素介导的光动力降解效果最佳,光照15 min时降解率高达91.08%。因此,确定的最佳条件为:光敏剂为姜黄素,浓度10 μmol/L,光照时间15 min。在最优条件下,相比于空白对照组,光动力对牡蛎中多环芳烃的降解率达到21.92%~88.46%。结论:光动力方法可有效降解牡蛎中的多环芳烃,该技术对于水产品中残留多环芳烃的降解是一种可行的方法,应用前景广阔。     

三硝基甲苯在四种水产品中的富集及微生物降解

为了保障水产品安全,本研究建立了一种高效提取2,4,6-三硝基甲苯（TNT）的方法,利用高效液相色谱（HPLC）法对花蚬子、白蚬子、长竹蛏、文蛤四种市售水产品的TNT富集能力进行检测,并利用微生物高效降解水中的TNT污染物。结果表明该方法提取率可达97.80%。四种水产品中花蚬子、白蚬子、文蛤均可对TNT有不同程度的积累,其中白蚬子对TNT的富集程度最高,浓度可达76.26 ng/g。为降解水体中的TNT污染物,选取了9种能够降解芳香环类化合物的天然菌株,开展了TNT的生物降解研究。结果显示9种天然菌株均能够降解TNT,其中H5、LM1、CT1的降解效果较好,弧菌H5的降解效率最高,在27 ℃的条件下降解TNT 9 h,降解效率可达80.90%。本研究建立的提取检测方法简单高效、重复性好,具有较好的应用前景。同时生物降解法能够高效、无二次污染地去除水中的TNT污染物。从而保障水体的安全。     

蔬菜对多环芳烃的吸收富集特性及清洗剂筛选

研究蔬菜在浸毒暴露下对多环芳烃（PAHs）的吸收特性及优选降解蔬菜中PAHs的最佳清洗剂。选取番茄、辣椒、茄子、黄瓜、白萝卜、豆角、油麦菜作为实验样本,分别在500 μg/kg的PAHs溶液浸毒2、4 h,检测蔬菜果皮等暴露部分和果瓤中PAHs含量,分析不同蔬菜对PAHs的富集特性;比较不同蔬菜中PAHs平均含量的变异系数,筛选均一试验材料,通过进一步实验确定蔬菜适宜的浸毒处理条件。应用8种清洗剂处理浸毒蔬菜,以5种PAHs降解效果为评价标准,优选最佳清洗剂。浸毒处理后,多数蔬菜表现出果皮等暴露部分对PAHs富集能力比果瓤强,并且随PAHs环数增加,向内迁移能力下降;通过比较PAHs含量变异系数得出,除油麦菜外,其它蔬菜均变现内外含量变化不一致,果瓤平均含量数据波动大;以油麦菜为试材,通过进一步试验确定浸毒条件为PAHs溶液浓度500 μg/kg,浸毒时间60 min。不同清洗剂处理对油麦菜中5种PAHs降解效果整体表现为轻质PAHs>重质PAHs,其中果蔬清洗剂和臭氧水降解效果最差,超声波清洗仅对轻质PAHs具有良好降解效果,降解率可达72.72%;优选清洗剂处理共7组且均为氧化剂处理,其中800 mg/L的Fenton （nH₂O₂:nFeSO₄=8∶1）试剂降解效果最好,对油麦菜中轻质PAHs平均降解率为79.29%,重质PAHs为59.07%。通过探究蔬菜对PAHs的富集特性及对比不同清洗处理对PAHs的降解效果,为有效控制污染及消费者挑选合理、高效清洗剂提供理论指导。     

以离子液作为介质萃取水中的多环芳烃

多环芳烃(PAHs)是一类具有难降解性、致癌性、环境累积性及非挥发性的有害化学物质。以16种EPA PAHs中的菲、荧蒽、芘这3种物质为研究对象,从检测器、提取试剂、提取方法等方面入手,对分析过程进行优化。在保证分析结果有较高精度的前提下,尽量地使分析过程简洁、高效。在样品的前处理阶段,选用超声提取法进行样品的前处理比较快捷。通过对3种多环芳烃(PAHs)标准样品的高效液相色谱法的定性、定量分析,结果表明,该方法可有效分离PAHs,回收率较高。最后,通过对实际水样中多环芳烃(PAHs)的测定验证该方法是令人满意的。     

铜绿假单胞菌对萘和菲降解特性研究

研究不同pH和温度条件下,铜绿假单胞菌（Pseudomonas aeruginosa）对多环芳烃中萘和菲的降解效果。结果表明,以活性炭为吸附载体,多环芳烃为唯一碳源,将此菌株培养48 h后,pH值为7.0时,萘的降解率可达25.68%,脱氢酶活性达到33.42 （μg/mL）·h;菲的降解率可达41.9%,脱氢酶活性达到37.44 （μg/mL）·h。当温度为37 ℃时,萘的降解率可达27.7%,脱氢酶活性达到33.60 （μg/mL）·h;菲的降解率可达34.5%,脱氢酶活性达到39.96 （μg/mL）·h。     

三种光敏剂介导的光动力对水体中8种多环芳烃的降解作用

为了探究不同光敏剂(姜黄素、核黄素、金丝桃素)介导的光动力对水体中多环芳烃的降解作用,以含有8种多环芳烃的水体为研究对象,在光敏剂浓度为10μM,光照时间为15 min的条件下,采用光动力方法处理并通过同步荧光法测定水体中的各种多环芳烃.结果表明,姜黄素介导的光动力对多环芳烃的降解效果明显优于核黄素和金丝桃素介导的光动...     

多环芳烃蒽在两种贝类中的检测及生物降解研究

目的 比较月亮贝(Neolamprologus calliurus)和竹蛏(Solen strictu)对多环芳烃蒽的富集作用,筛选获得高效蒽降解菌株.方法 采用气相色谱-质谱法(gas chromatohraphy-mass spectromety,GC-MS)检测两种贝类中蒽的含量,采用高效液相色谱法(high p...     

几种水产品中雌激素的检测及其微生物降解的研究

部分养殖户在池塘中人为添加具有"催生"能力的激素饲料,以达到促进水产品快速生长的目的。过量的雌激素已经成为影响水产品安全和人类健康的一个重大问题。生物降解是一种环境友好且经济安全的方法,可以用来减少雌激素对环境的危害。建立了一种从水产品中高效提取雌二醇的方法,并利用高效液相色谱(HPLC)法对市售花蛤、蛏子、海螺、海锥、黄花鱼、青虾等水产品中的雌二醇进行检测。结果表明:在海螺和海锥中发现了雌二醇的富集。选择4株天然降解甾体类化合物的菌株开展降解雌二醇的研究,结果表明:这4种菌株均具有降解雌二醇的能力,其中睾丸酮丛毛单胞菌(CT1)的降解效率最高。     

湖北省水产品中持久性有机污染物残留状况分析

目的了解湖北省居民日常消费的水产品中持久性有机污染物的残留情况。方法采集水产品品种39种共285批次,采用气相色谱-质谱法测定水产品中的16种多环芳烃、15种有机氯农药及相关降解产物和31种多氯联苯单体残留,并进行统计分析。结果3环化合物检出率为46%,4环化合物检出率为36%,水产样品中检出的多环芳烃类目标物以3环、4环为主,为中、低环化合物,6环化合物在所有样品中均未检出。各品种鱼体内多环芳烃总量排序为:鲫鱼>鳊鱼、刁子鱼>草鱼、财鱼、桂鱼、鲶鱼、鲢鱼>龙虾、泥鳅、黄鳝、黄颡鱼,多环芳烃总量最高的为鲫鱼,检出含量为85.34μg/kg。结论在湖北省养殖环节和流通环节的水产品中,多环芳烃类化合物残留主要为蒽、芴、萘、菲,均为3环、4环化合物;未检出多氯联苯类化合物;水产样品中有机氯农药残留主要为滴滴涕、氧氯丹、六氯苯。     

优化QuEChERS结合LC-MS-MS法测定水产品中8种多环芳烃的研究

以市售常见的水产品为研究对象,建立并优化了QuEChERS结合LC-MS-MS测定水产品中8种多环芳烃残留量的方法。样品经超声辅助乙腈提取,经C18和弗洛里硅土双连接层析柱净化后,采用液相色谱-质谱检测器对多环芳烃进行检测分析。结果表明,8种多环芳烃分离效果好,检出限(LOD)为0.006～0.105μg/kg,相对标准偏差为0.3%～4.0%(n=4),加标回收率达到86%～110%。这表明该方法具有比较高的重现性和选择性,对于水产品中多环芳烃的残留测定具有很好的应用价值。     

Inclusion of persistent organic pollutants in humification processes: direct chemical incorporation of phenanthrene via oxidative coupling

The participation of phenanthrene in phenol-coupling reactions mediated by horseradish peroxidase was investigated. Aqueous-phase concentrations of phenanthrene were observed to decrease dramatically with phenol as a result of the formation of precipitated products, suggesting a potential means for simultaneous treatment of phenolic contaminants and polycyclic aromatic hydrocarbons (PAHs) using peroxidase-mediated oxidative coupling processes. The studies reveal that phenanthrene removal from the aqueous phase occurs by a combination of sorption by and chemical bonding to precipitated reaction products. In that the oxidative coupling reactions of phenolics comprise an important step in the initiation of humification processes, the results obtained provide insights to potential roles that natural humification may play in the sorption, sequestration, and environmental fate of PAHs and other organic xenobiotics of similar nature.     

Polycyclic aromatic hydrocarbons in animal-based foods from Shanghai: bioaccessibility and dietary exposure

A total of 175 samples of 18 types of food were collected from markets in Shanghai, China, and the concentrations and bioaccessibility of 15 priority-controlled polycyclic aromatic hydrocarbons (PAHs) in these samples were determined. The mean concentrations of PAHs varied between 2.4 and 47.1?ng?g^?1 wet weight, with the highest being observed in snail and lowest in chicken. The concentrations were lower than the maximum levels of PAH allowed for food per EU regulations. Among the PAHs measured, phenanthrene was the predominant one. Most of the PAHs originated from pyrogenic sources, analysed using molecular indices. The mean bioaccessibility of PAHs varied from 29.0% to 61.2% as measured by simulating the human gastrointestinal digestion process. Linear relationships between the bioaccessibility and lipid contents were observed for most PAH congeners. The daily intake of PAHs by an average Shanghai resident was 848?ng?day^?1 and decreased to 297?ng?day^?1 when the bioaccessibility of PAHs were considered, demonstrating that most intake might have been overestimated. According to the potency equivalent concentrations and screening values of PAHs, consumption of snail and clam, especially snail, should be limited.     

Polycyclic aromatic hydrocarbons in human milk of nonsmoking U.S. women

The determination of polycyclic aromatic hydrocarbons (PAHs) in human milk is relevant in assessing the dose to mothers and infants. Since measurements for the United States are lacking, we analyzed 13 PAHs in human milk from 12 nonsmoking American mothers. Analytes were extracted from milk by using a combination of centrifugation, liquid-liquid, and solid-phase extraction techniques. Following method validation with spiked bovine milk, PAH concentrations in human milk were determined by isotope dilution gas chromatography/mass spectrometry. Phenanthrene, fluorene, fluoranthene, and pyrene were found at median concentrations of 11.8, 3.0, 1.6, and 1.1 ng/g milk fat, respectively, whereas 9 additional analytes including benzo[a]pyrene were not detected (<0.04 ng/g). Calculated average daily doses from ingestion (high: 75.8, phenanthrene; low: 6.1 ng/kg/day pyrene) were compared to doses from air pollution inhalation. Milk ingestion accounted for 47.9-81.4% of the total dose of individual PAHs to the infant. However, calculated total average daily doses of phenanthrene and pyrene from ingestion and inhalation combined (12.2 to 110.3 ng/kg-day, respectively) were 3 orders of magnitude lower than documented doses known to cause health effects. These first measurements of PAH levels in U.S. human milk are comparable to concentrations reported previously for European and Asian women.     

Influence of nonionic surfactant on attached biofilm formation and phenanthrene bioavailability during simulated surfactant enhanced bioremediation

Surfactant effects on preformed attached biofilm formation and the biodegradation of soil-sorbed phenanthrene were monitored using a continuously flowing flowcell system. Thirty-two flowcell reactors were constructed to monitor phenanthrene degradation and biofilm formation under five different surfactant concentrations. Initially, all flowcell reactors were operated without surfactant for 25 days to allow for the formation of an attached bacterial biofilm on phenanthrene spiked soil; after that, a model nonionic surfactant (Triton X-100) was applied to the flowcell reactors at five different concentrations (0, 100, 200, 500, and 1000 mg/L), which represent concentrations below (0 and 100 mg/L) and above (200, 500, and 1000 mg/L) the critical micelle concentration (cmc). The results obtained in this study reveal that bacterial biofilm formation with extracellular polymeric substances was the strategy of bacteria to utilize partially soluble PAHs. However, in the presence of surfactant, this strategy was modified. The presence of surfactant at all concentrations changed the physiological aspects of the attached biofilm, and the bioavailability of the phenanthrene increased with the addition of surfactant above the cmc.     

Competitive sorption between 17alpha-ethinyl estradiol and naphthalene/phenanthrene by sediments

Steroid hormones such as 17alpha-ethinyl estradiol (EE2) have been frequently detected at various levels in surface waters downstream of many municipal wastewater treatment facilities. Their fate, transport, and environmental risk are currently not well characterized. This study examined the competitive sorption between EE2 and two aromatic hydrocarbon compounds, phenanthrene and naphthalene, by three sediments. The sorption isotherms of phenanthrene and naphthalene were measured at 22 +/- 0.5 degrees C using a batch technique with initial aqueous concentrations (Co) of EE2 at 0, 100, 500, and 2000 microg/L. Competitive sorption varied between EE2 and phenanthrene or naphthalene on the sediments. The linearity of the naphthalene sorption isotherm was found to increase as a function of the cosorbate EE2 concentration from 0 to 2000 microg/L. The single-point naphthalene KD value at equilibrium aqueous-phase naphthalene concentration (Ce) of 25 microg/L was reduced by 19-26% and 27-48% at Co (EE2) = 100 and 500 microg/L, respectively. The sorption of phenanthrene at its low Ce range was similarly affected by EE2, but to a much less extent, possibly because phenanthrene is more hydrophobic than EE2. At high phenanthrene Ce, no measurable change was observed even at CO (EE2) = 2000 microg/L. While the effect of naphthalene on EE2 sorption was insignificant, the competitive effect on the sorption of EE2 by phenanthrene was very significant at low EE2 concentrations. The measured single-point EE2 KD values decreased as much as 35% as the phenanthrene Ce increases from below 10 microg/L to slightly above 100 microg/L. This study suggests that the fate and transport of emerging pollutants such as EE2 could be affected in the presence of more hydrophobic pollutants in aquatic systems.     

四川泡菜中降解亚硝酸盐乳酸菌的筛选鉴定及其应用

从四川传统泡菜中分离疑似乳酸菌170株,通过溶钙力测定获得33株产酸力较强的菌株,然后对其进行亚硝酸盐降解力初筛试验,得到5株具有较强降解亚硝酸盐能力的菌株,再采用控制pH值的方法从中筛选出1株酶降解亚硝酸盐作用明显的菌株N2,该菌株按0.1%(v/v)接种量接种于含125 mg/L NaNO2、pH 6.4和添加有2%CaCO3(w/v)的MRS培养基中,于30℃、120 r/min振荡培养72 h,对NaNO2的降解率达90.81%。菌株N2经形态学、生理生化特征及16S rDNA序列分析被鉴定为植物乳杆菌(Lactobacillus plantarum)。接种菌株N2发酵泡菜,测定发酵过程中泡菜pH值、亚硝酸盐含量,与自然发酵泡菜比较,菌株N2应用于发酵泡菜中降解亚硝酸盐的效果显著。