Mercury bioaccumulation in fish in an artificial lake used to carry out cage culture

As a global toxic pollutant,mercury(Hg)bioaccumulation within food chain could be influenced by human disturbance.Ten typical fish species were collected from Changshou Lake,an artificial lake used to carry out cage fish culture,to investigate the C/N isotopic compositions and Hg bioaccumulation in fish.The results showed that the total Hg(THg)and methylmercury(MeHg)levels in fish muscles((56.03±43.96)and(32.35±29.57)ng/g,wet weight),comparable with those in most studies in China,were significantly lower than the international marketing limit(0.5 mg/kg).Past human input for cage culture in this lake led to abnormal~(15)N enrichment in food chain,as the quantitative trophic levels based onδ~(15)N were different with that classified by feeding behaviors.This phenomenon subsequently demonstrated that it should be considered thoughtfully with respect to the application of the traditional method for understanding Hg bioaccumulation power by the slope of log_(10)[Hg]withδ~(15)N regression in specific water body(i.e.,Changshou Lake).In addition,no significant linear correlation between Hg and body weight or length of some fish species was observed,suggesting that the fish growth in the eutrophic environment was disproportionate with Hg bioaccumulation,and fish length or weight was not the main factor affecting Hg transfer with food web.The occurrence of human disturbance in aquatic system presents a challenge to a better understanding of the Hg bioaccumulation and biomagnification within the food chain.     

HCB与γ-HCH在辽河沉积物中的缺氧降解动力学

为全面认识多氯有机物在天然水沉积物中的转化行为,利用超声波发生仪萃取沉积物样品,采用气相色谱仪(Ni63-ECD)定量分析,在缺氧条件下,测定了辽河沉积物中六氯苯(HCB)、γ-HCH的微生物降解速率.在单个培养体系中,测定出不外加有机碳源,外加葡萄糖和乙酸钠3种条件下HCB、γ-HCH的缺氧降解符合准一级动力学方程,动力学常数分别为HCB k(不外加有机碳源)=0.0014d-1, k(葡萄糖)= 0.0033d-1, k(乙酸钠)= 0.0052d-1;γ-HCH k(不外加有机碳源)=0.0454d-1, k(葡萄糖)=0.1143d-1, k(乙酸钠)=0.1451d-1.在2种氯代物混合培养体系中,HCB、γ-HCH的降解速率均有所下降.经GC-MS测定,三氯苯、二氯苯分别是HCB、γ-HCH的主要降解产物.     

室外大气颗粒物中痕量砷和锑测定的研究

采用微波消解-氢化物发生-原子荧光光谱法，用L-半胱氮酸预还原法对室外大气颗粒物中砷和锑进行了分析。讨论并确定了实验的最佳测定条件，结果表明，砷和锑的检出限分别为0．058ng／mL和0．075ng／mL，回收率为101．8％和98．4％，相对标准偏差分别为0．6％和0．9％。该法准确、快速、简便，应用于室外大气颗粒物中砷和锑的测定，结果满意。     

控制挥发性有机化合物污染的技术

介绍了工业生产中排放的挥发性有机化合物的种类,主要排放源及其处理方法,并着重介绍了世界上比较先进的蓄热式燃烧法和蓄热式催化氧化法。     

活性炭纤维对水中低浓度柴油的吸附特性研究

研究了活性炭纤维(ACF)对水中低浓度柴油的吸附特性。通过静态吸附试验,考察了吸附时间、温度和pH等因素对吸附速率和吸附行为的影响。结果表明:ACF吸附速度快,35 min去除率达81.5%;在10～30℃范围内吸附温度越高效果越好,10℃吸附1 h时的去除率为91.4%;pH适应范围广,2.7相似文献   

Methyl tertiary-butyl ether inhibits THP-1 macrophage cholesterol efflux in vitro and accelerates atherosclerosis in ApoE-deficient mice in vivo

The biosafety of methyl tertiary-butyl ether (MTBE), mainly used as a gasoline additive, has long been a contentious topic. In addition to its routine toxicities, MTBE has been demonstrated to disrupt glucose and lipid metabolism and contribute to the development of type 2 diabetes as well as obesity. As one of the morbidities related to dyslipidemia, atherosclerosis is worthy of being investigated under MTBE exposure. Since foam cells derived from macrophages play pivotal roles during atherosclerosis development, we studied the effects of MTBE on macrophages in vitro and assessed the effect of MTBE on atherosclerosis plaque formation with the ApoE^?/? mouse model in vivo for the first time. Our results demonstrated that exposure to MTBE at environmentally relevant concentrations decreased the expression of ABCA1 and ABCG1, which are responsible for macrophage cholesterol efflux, at both mRNA and protein levels in THP-1 macrophages. Consequently, treatment with MTBE inhibited the transport of cholesterol from macrophages to High-density lipoprotein. ApoE^?/? mice exposed to MTBE at environmentally relevant concentrations (100, 1000 μg/kg) displayed significant increases in lesion area in the aorta and aortic root compared to vehicle-treated ones. Further analysis indicated that MTBE exposure enhanced the macrophage-specific marker Mac-2 contents within plaques in the aortic root, implying that MTBE could promote macrophage-derived foam cell formation and thus accelerate atherosclerosis plaque formation. We for the first time demonstrated the pro-atherogenic effect of MTBE via eliciting disruption of macrophage cholesterol efflux and accelerating foam cell formation and atherosclerosis plaque development.     

应用物种敏感性分布评价敌敌畏对淡水生物的生态风险

敌敌畏是一类重要的有机磷杀虫剂,但其对水生生态的影响至今研究较少。为了评价其生态风险,构建了淡水水生生物对敌敌畏的物种敏感性分布(species sensitivity distribution,SSD)模型,在此基础上,讨论了影响SSD模型的主要因素;并分析了该模型的不确定性;推导了敌敌畏对不同类别生物的5%危害浓度HC5(hazardous concentration for 5%the species)阈值;整理收集了我国重要流域水体中敌敌畏的环境浓度;结合SSD模型计算了对淡水生物的潜在影响比例(potentially affected fraction,PAF)。结果表明:1)不同模型的选择会影响HC5的结果,且Burr III模型拟合结果较好,推导的HC5值为0.37μg·L-1;2)无脊椎动物在敌敌畏低浓度范围内的敏感性明显高于脊椎动物。甲壳类动物与昆虫和蜘蛛类相似,敏感度较高,鱼类则较低;3)应用Burr III模型构建SSD时,参数k值对HC5最为敏感,蒙特卡罗随机模拟得到HC5变化范围为0.05~40.57μg·L-1,均值为5.07μg·L-1;4)敌敌畏对我国淡水生态影响较小,PAF均低于1%,其中黄河和太湖流域敌敌畏的生态风险高于其他河流湖泊,珠江口和南海北部较低。上述研究结果为评价敌敌畏对全国不同水体水生生物的潜在生态风险提供了科学依据。     

闽西北马尾松人工林营养元素的积累与分配格局

通过定位监测与取样分析,研究了41 a生马尾松人工林生态系统中的林木、林下植被、地被物及土壤等各组分营养元素含量、积累及分配特征.对林木的养分含量分析显示,除Ca元素外,针叶的养分含量最高,其次是枝、根、皮,树干的养分含量最低.林下植被层的养分含量比较高,其养分含量大小排列顺序为Ca＞N＞K＞Mg＞P;凋落物中各元素的含量与林木养分含量基本一致;土壤中K含量最高,其次是Mg,而Ca、N、P的含量则比较低.通过对林木生产力的分析表明,马尾松的养分年积累量为110.79 kg·hm-2·a-1,其中叶占34.47%,树干占22.56%,皮、枝和根分别占21.43%、10.91%和10.63%.马尾松林生态系统养分总贮量为187864.77 kg hm-2,其中土壤占98.70%,林木占1.18%,林下植被和凋落物养分元素总贮量较低,仅占总贮量的0.12%.     

Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)

• Simultaneous removal of organic contaminants and Pb(II) was achieved by Mn(VII). • Pb(II) enhanced Mn(VII) oxidation performance over a wide pH range. • Pb(II) did not alter the pH-rate profile for contaminants oxidation by Mn(VII). • Mn(VII) alone cannot oxidize Pb(II) effectively at pH below 5.0. • Pb(III) plays important roles on enhancing Mn(VII) decontamination process. The permanganate (Mn(VII)) oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds. Nonetheless, only a few studies have been conducted to explore the role of the heavy metals (especially the redox-active ones) during the Mn(VII) oxidation process. In this study, taking Pb(II) as an example, its influence on the Mn(VII) decontamination performance has been extensively investigated. It was found that, with the presence of Pb(II), Mn(VII) could degrade diclofenac (DCF), 2,4-dichlorophenol, and aniline more effectively than without. For instance, over a wide pH range of 4.5–8.0, the dosing of 10 μmol/L Pb(II) accelerated the DCF removal rate from 0.006–0.25 min⁻¹ to 0.05–0.46 min⁻¹ with a promotion factor of 1.9–9.4. Although the UV-vis spectroscopic and high resolution transmission electron microscopy analyses suggested that Mn(VII) could react with Pb(II) to produce Mn(IV) and Pb(IV) at pH 6.0–8.0, further experiments revealed that Pb(II) did not exert its enhancing effect through promoting the generation of MnO₂, as the reactivity of MnO₂ was poor under the employed pH range. At pH below 5.0, it was interesting to find that, a negligible amount of MnO₂ was formed in the Mn(VII)/Pb(II) system in the absence of contaminants, while once MnO₂ was generated in the presence of contaminants, it could catalyze the Pb(II) oxidation to Pb(IV) by Mn(VII). Collectively, by highlighting the conversion process of Pb(II) to Pb(IV) by either Mn(VII) or MnO₂, the reactive Pb(III) intermediates were proposed to account for the Pb(II) enhancement effect.     

Advances in airborne microorganisms detection using biosensors: A critical review

• Airborne microorganism detection methods are summarized. • Biosensors play an important role in detecting airborne microorganisms. • The principle of biosensor detection of airborne microorganisms is introduced. • The application and progress of biosensor in recent years is summarized. • The future perspectives of biosensor are identified. Humanity has been facing the threat of a variety of infectious diseases. Airborne microorganisms can cause airborne infectious diseases, which spread rapidly and extensively, causing huge losses to human society on a global scale. In recent years, the detection technology for airborne microorganisms has developed rapidly; it can be roughly divided into biochemical, immune, and molecular technologies. However, these technologies still have some shortcomings; they are time-consuming and have low sensitivity and poor stability. Most of them need to be used in the ideal environment of a laboratory, which limits their applications. A biosensor is a device that converts biological signals into detectable signals. As an interdisciplinary field, biosensors have successfully introduced a variety of technologies for bio-detection. Given their fast analysis speed, high sensitivity, good portability, strong specificity, and low cost, biosensors have been widely used in environmental monitoring, medical research, food and agricultural safety, military medicine and other fields. In recent years, the performance of biosensors has greatly improved, becoming a promising technology for airborne microorganism detection. This review introduces the detection principle of biosensors from the three aspects of component identification, energy conversion principle, and signal amplification. It also summarizes its research and application in airborne microorganism detection. The new progress and future development trend of the biosensor detection of airborne microorganisms are analyzed.