腐殖酸与典型碳纳米材料协同光致产生活性氧物种的研究

采用电子自旋共振光谱(EPR)技术,分析腐殖酸在光照下对4种典型碳纳米材料诱导产生单线态氧(~1O_2)和羟基自由基(·OH)的影响。基于密度泛函理论计算4种典型碳纳米材料的前线轨道能,比较了它们分别经能量转移诱导产生~1O_2的能力以及经电子传递诱导产生·OH的能力。结果显示,4种不同形状的碳纳米材料(富勒烯、单壁碳纳米管、多壁碳纳米管以及石墨烯)悬浮液在紫外光照下均无~1O_2和·OH产生。与腐殖酸共同存在下,4种碳纳米材料均显著诱导~1O_2的产生,且富勒烯和石墨烯还能光致生成·OH。协同产生~1_O2的能力大小为:单壁碳纳米管富勒烯多壁碳纳米管石墨烯,协同产生·OH的能力大小为:石墨烯富勒烯。~1O_2的产生能力与碳纳米材料的能隙大小和颗粒聚集程度有关,而诱导产生·OH的能力主要取决于化学硬度。总之,我们的研究表明腐殖酸与碳纳米颗粒可协同产生活性氧物种。     

丙烯腈诱导的氧化应激对大鼠睾丸NF-κB信号通路的影响

为探索丙烯腈(acrylonitrile,ACN)诱导的氧化应激对大鼠睾丸NF-κB信号通路的影响,将50只SPF级健康SD雄性大鼠按体重随机分为12.5、25、50 mg·kg~(-1)ACN染毒组,50 mg·kg~(-1)ACN+300 mg·kg~(-1)N-乙酰半胱氨酸(N-acetylcysteine,NAC)干预组(NAC干预组),对照组(给予等体积玉米油),每组10只,灌胃,1次/天,6天/周,共90 d。可见光分光光度法检测睾丸组织中超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)、还原型谷胱甘肽/氧化型谷胱甘肽比值(glutathione/oxidized glutathione,GSH/GSSG)、丙二醛(malondialdehyde,MDA)。免疫荧光染色法检测睾丸核因子-κB(nuclear factorκB,NF-κB)激活及核转移。Western Blot检测睾丸p65、IκB蛋白表达。结果显示,低、高剂量染毒组大鼠睾丸GSH/GSSG比值、GSH-Px酶活性与对照组比较降低(P0.05)。中、高剂量染毒组大鼠睾丸MDA含量与对照组比较升高(P0.05)。NAC干预组大鼠睾丸MDA含量与高ACN组比较降低(P0.05);NAC干预组大鼠睾丸GSH/GSSG比值与高ACN组比较升高(P0.05);免疫荧光结果显示,高ACN组大鼠睾丸NF-κB被激活,并转移入细胞核。NAC干预组与高ACN组比较p65蛋白表达及核转移显著减少。Western Blot结果显示,高剂量染毒组大鼠睾丸p65蛋白表达与对照组比较升高(P0.05),IκB蛋白表达与对照组比较降低(P0.05);NAC干预组大鼠睾丸p65蛋白表达与高ACN组比较降低,IκB蛋白表达与高ACN组比较升高,差异有统计学意义(P0.05)。结果表明丙烯腈引起的氧化应激激活了大鼠睾丸生殖细胞NF-κB信号通路。     

小麦根系菲与磷吸收及转运的相互作用

作物根系对多环芳烃(PAHs)与磷吸收及转运之间的相互作用研究对农产品的安全生产和PAHs污染环境植物修复的强化具有重要意义。为此,本文以菲为PAHs的代表,采用水培试验研究了不同磷、菲水平下小麦根系菲、磷吸收及其转运的效果,旨在揭示植物根系吸收PAHs与磷素的相互作用。结果表明,在0~1 200μmol·L~(-1)磷浓度范围内,小麦根系、茎叶菲含量在低磷浓度(10μmol·L~(-1))时最高,分别为36.87 mg·kg~(-1)和2.07 mg·kg~(-1);磷含量总体呈现随磷处理浓度的升高而增大的趋势;成对数据t-检验显示无论加菲与否,根系、茎叶磷含量无显著性差异(P0.05)。磷可促进菲从根部向地上部转运,而菲对磷转运没有显著性影响。在低磷浓度下(10μmol·L~(-1)),随着菲浓度的升高,小麦根系、茎叶菲含量呈现显著升高趋势(P0.05)。磷、菲共存处理介质pH升高幅度大于单一处理。     

纳米硫化镉对A549细胞的损伤研究

研究纳米硫化镉(Nano-Cd S)材料对肺癌细胞系A549的毒性及氧化损伤作用。培养A549细胞,经传代后接种于6孔板中,每孔2 m L完全培养基,接种次日进行染毒。用直径20~30 nm、长度80~100 nm的Nano-Cd S进行染毒,染毒浓度分别为0、5、10、20、40和80 mg·L~(-1)。染毒24 h后用MTT检测细胞存活率,以存活率在80%左右的浓度为后续实验染毒浓度。应用流式细胞技术,用荧光探针法检测A549细胞的活性氧(reactive oxygen species,ROS)含量,PI-Annexin-V法检测细胞凋亡情况;用试剂盒检测细胞中超氧化物岐化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)活性以及丙二醛(malondialdehyde,MDA)含量,判断细胞氧化损伤情况。不同浓度Nano-Cd S处理细胞24 h之后,细胞存活率随剂量的增加而下降,浓度为10、20、40和80μg·L~(-1)时,存活率分别为(88.71%±0.80%)、(81.93%±3.06%)、(75.23%±1.13%)和(70.66%±5.63%),且各组间差异均具有统计学意义(P0.05)。以浓度为10和20 mg·L~(-1)的Nano-Cd S染毒24 h后,胞内ROS含量和细胞凋亡率随染毒剂量的增加而增加(P0.05);浓度为10 mg·L~(-1)时,细胞凋亡率为(6.26%±0.44%)。与对照相比,各染毒组SOD和CAT活性和MDA含量升高,20 mg·L~(-1)染毒组SOD和CAT活性和MDA含量高于10 mg·L~(-1)染毒组(P0.05)。研究表明,纳米硫化镉能引起A549细胞的氧化损伤和细胞凋亡,具有明显的细胞毒性。     

Effects of freshwater leaching on potential bioavailability of heavy metals in tidal flat soils

Environmental Geochemistry and Health - Leaching experiments were conducted to investigate the effects of desalination levels and sediment depths on potential bioavailability of heavy metal (Cd,...     

珠江河网水产品中菊酯类农药残留调查及健康风险评价

2012年8月在珠江河网采集水产品样品(13种鱼,4种虾和2种贝),采用超声波提取-气相色谱法对样品中菊酯类农药(PYRs)进行残留检测,并对鱼类PYRs暴露水平进行健康风险评价。结果显示,鱼类肌肉、虾类和贝类中PYRs质量分数分别介于ND~3.05μg·kg-1、0.05~1.13μg·kg-1和0.69~1.20μg·kg-1(ND为未检出,以湿重计),平均值分别为0.90μg·kg-1、0.41μg·kg-1和0.99μg·kg-1。虾类和贝类中PYRs的检出率均很高,除联苯菊酯在虾类体内检出率为75%外,其他菊酯均为100%,鱼类肌肉中氯菊酯检出率最高,达到100%。氯菊酯在鱼类肌肉和贝类中的检出量最高,分别占总菊酯质量分数的52.2%和55.4%,溴氰菊酯在虾类中检出量最高,分别占总菊酯质量分数的33.0%;对居民通过食物摄入的PYRs进行食用暴露风险评估,结果表明,珠江河网水产品中PYRs人体健康危害的年总风险评价介于3.96×10-13~1.21×10-10a-1,水产品的安全消费量为5.54×104kg·d-1,水产品中的PYRs的健康危险风险很小。     

气相分子吸收光谱法测定印染废水中氨氮的影响因素

采用气相分子吸收法光谱测定印染废水中的氨氮,并对相关影响因素进行探讨。结果证实,硫化物和尿素会对氨氮的测定产生负干扰,硫化物干扰可用乙酸锌-乙酸钠固定液沉淀法去除,尿素干扰可以用稀释法去除,但仅适用于氨氮质量浓度0.10 mg/L且稀释后尿素质量浓度≤100 mg/L的水样;苯胺、浊度和色度对测定无干扰,可直接检测。     

<Emphasis Type="Italic">Synechococcus</Emphasis> production and grazing loss rates in nearshore tropical waters

Temporal variation of Synechococcus, its production (μ) and grazing loss (g) rates were studied for 2 years at nearshore stations, i.e. Port Dickson and Port Klang along the Straits of Malacca. Synechococcus abundance at Port Dickson (0.3–2.3 × 10⁵ cell ml^?1) was always higher than at Port Klang (0.3–7.1 × 10⁴ cell ml^?1) (p < 0.001). μ ranged up to 0.98 day^?1 (0.51 ± 0.29 day^?1), while g ranged from 0.02 to 0.31 day^?1 (0.15 ± 0.07 day^?1) at Port Klang. At Port Dickson, μ and g averaged 0.47 ± 0.13 day^?1 (0.29–0.82 day^?1) and 0.31 ± 0.14 day^?1 (0.13–0.63 day^?1), respectively. Synechococcus abundance did not correlate with temperature (p > 0.25), but nutrient and light availability were important factors for their distribution. The relationship was modelled as log Synechococcus = 0.37Secchi ? 0.01DIN + 4.52 where light availability (as Secchi disc depth) was a more important determinant. From a two-factorial experiment, nutrients were not significant for Synechococcus growth as in situ nutrient concentrations exceeded the threshold for saturated growth. However, light availability was important and elevated Synechococcus growth rates especially at Port Dickson (F = 5.94, p < 0.05). As for grazing loss rates, they were independent of either nutrients or light intensity (p > 0.30). In nearshore tropical waters, an estimated 69 % of Synechococcus production could be grazed.     

Histopathological changes in zebrafish embryos exposed to DLPCBs extract from Zhanjiang coastal sediment

Dioxin-like polychlorinated biphenyls (DLPCBs) are ubiquitous persistent pollutants that cause adverse effects in many environmental organisms. DLPCBs in marine sediments can be absorbed by benthic organisms, bioaccumulate, and biomagnify through the food chain and threaten animal and human health. There are no reports of DLPCBs concentrations in the Zhanjiang Gulf seabed. This study was designed to investigate the concentration of DLPCBs in the Zhanjiang coastal sediment and histopathological changes in zebrafish (Diano rerio) embryos exposed to environmentally relevant concentrations of DLPCBs. Of the five sites selected, two sites TS and JSW contained DLPCBs at concentrations of 0.08 and 22.54 ng/g dry sediment, respectively. Two groups of zebrafish embryos were used. One group was exposed to 3.75, 7.5, 15, 30, and 60 mg/ml of DLPCBs extracted from the sediments sampled from the TS site and the second group to 4.375, 8.75, 17.5, 35, and 70 mg/ml of DLPCBs from JSW site from 0.75 h post-fertilization (hpf) to 96 hpf. The zebrafish exposed to 60 and 70 mg/ml of DLPCBs at 96 hpf displayed gross histopathological changes with cardiac lesions including pericardial edema being the most deleterious. Other changes observed were hydropic degeneration of gill filaments and hepatocytes, loss of intestinal folds, and uninflated swim bladder. It appears that only a few sites of the Zhanjiang gulf are contaminated with DLPCBs. This is the first report of histopathological changes in the gills, hepatocytes, intestines, heart, and the swim bladder in zebrafish embryos exposed to DLPCBs from a coastal sediment. Further studies with sampling at different stages of development are required to identify which organ/tissue is most sensitive to DLPCBs.