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811.
纳米银(AgNPs)以其独特的抗菌性能在生物医药和消费品中得到大量应用。然而,随着人类接触AgNPs的机会增多,AgNPs暴露的潜在危害也不容忽视。体内研究表明,AgNPs可以通过经口、呼吸、腹腔、静脉等途径进入机体,进而通过血液或淋巴液的流动分散到全身不同组织器官。而不同的暴露方式、暴露剂量、AgNPs粒径、表面包被和电荷以及暴露器官本身的特点可能对AgNPs在体内的分布与蓄积产生影响。因此,本文系统地总结了AgNPs进入生物体的途径及其在生物体内的组织分布,讨论了影响AgNPs体内生物分布和蓄积的因素。 相似文献
812.
Application of ultra-sonication,acid precipitation and membrane filtration for co-recovery of protein and humic acid from sewage sludge 总被引:1,自引:0,他引:1
Liangliang WEI Kun WANG Xiangjuan KONG Guangyi LIU Shuang CUI Qingliang ZHAO Fuyi CUI 《Frontiers of Environmental Science & Engineering》2016,10(2):327-335
A novel method was applied to co-recover proteins and humic acid from the dewatered sewage sludge for liquid fertilizer and animal feed. The proteins in sewage sludge were first extracted using the processes of ultra-sonication and acid precipitation, and then the humic acid was recovered via membrane filtration. The extraction efficiency was 125.9 mg humic acid?g−1VSS volatile suspended solids (VSS) and 123.9 mg proteins?g−1 VSS at the optimal ultrasonic density of 1.5 W?mL−1. FT-IR spectrum results indicated that the recovered proteins and humic acid showed similar chemical characteristic to the natural proteins and humic acid. The acidic solution (pH 2) could be recycled and used more than 10 times during the co-recovery processes. In addition, the dewatered sludge could be easily biodegraded when the humic acid and proteins are extracted, which was essential for further utilization. These findings are of great significance for recovering valuable nutrient from sewage sludge. 相似文献
813.
采用氢化物发生-原子荧光光谱法测定了成都东郊4块稻田水中砷的形态.研究发现,该区域稻田表面水砷浓度平均值为3.15—7.9μg.L-1,土壤孔隙水为18.71—53.71μg.L-1,除4号稻田土壤孔隙水外,其余各稻田表面水及土壤孔隙水中砷浓度的平均值均未超出国家农田灌溉水质标准.垂直方向上,土壤孔隙水中各形态砷的浓度均比稻田表面水中的高,且都在水-土界面或接近界面处最大,然后依次向下呈递减趋势.水平方向上,各形态砷的浓度因所处稻田条件的不同而分布各异.各形态砷在所研究稻田水中的分布皆呈现出可溶态砷>颗粒态砷、三价砷>五价砷的特征. 相似文献
814.
增加投放量对贝类养殖水环境影响的模拟研究 总被引:1,自引:0,他引:1
以采集于大连市大窑湾海青岛养殖场的海湾扇贝、虾夷扇贝和牡蛎为研究对象,在实验室模拟增加养殖量的条件下,通过系列检测生态缸中海水的水化指标,探讨了养殖贝类对水环境的影响.实验结果表明:在贝类养殖的过程中,随着养殖生物量的增加,生物体排泄物随之增加,进而造成耗氧量、TOC、CODMn、BOD5和NH4^ -N浓度的增加,DO下降.排泄物的分解、氧化作用使水中pH轻度下降、无机氮浓度急剧增大.由生物污染造成的水质恶化,导致生物死亡率增大。 相似文献
815.
816.
Coelomactra antiquata is a commercially important bivalve species, but has been suffering from severe population decline due to over-exploitation
and the deterioration of environmental conditions. Previous genetic survey of C. antiquata conducted with allozymes combined with morphology revealed high levels of genetic differentiation between northern and southern
populations which suggests a cryptic species might exist in C. antiquata. To test this hypothesis, amplified fragment length polymorphisms (AFLPs) and 16S rRNA gene sequence were used to re-evaluate
the spatial genetic structure of six populations of C. antiquata along the coast of China. Both genetic markers display a sharp genetic break between the four northern populations (northern
lineage) and two southern population (southern lineage). Large numbers of private alleles (AFLP) were found within the northern
or southern populations and a deep divergence of about 6.5% in 16S rRNA gene sequence between the northern and southern lineages
suggests the occurrence of potential cryptic or sibling species of C. antiquata. Applying previously published rates of mutation, divergence between the two lineages is estimated to have occurred approximately
3 million years ago and may be due to allopatric isolation during the middle Pliocene times. While no genetic differentiation
was found within the northern or southern populations in both AFLP and 16S mtDNA markers, the results indicate that the northern
and southern lineage should be managed separately and any translocation between the two areas should be avoided. 相似文献
817.
Dan Wu Chunyan Zhang Changjun Geng Li Hao Xie Quan 《Frontiers of Environmental Science & Engineering》2009,3(4):483-491
Waste gases from oil refining wastewater treatment plants are often characterized by the presence of multicomponent and various concentrations of compounds. An evaluation of the performance and feasibility of removing multicomponent volatile organic compounds (VOCs) in off-gases from oil refining wastewater treatment plants was conducted in a pilot-scale compost-based biofilter system. This system consists of two identical biofilters packed with compost and polyethylene (PE). This paper investigates the effects of various concentrations of nonmethane hydrocarbon (NMHC) and empty bed residence time (EBRT) on the removal efficiency of NMHC. Based on the experimental results and practical applications, an EBRT of 66 s was applied to the biofilter system. The removal efficiencies of NMHC were within the range of 47%–100%. At an EBRT of 66 s, the average removal efficiency of benzene, toluene, and xylene were more than 99%, 99%, and 100%, respectively. The results demonstrated that multicomponent VOCs in off-gases from the oil refining wastewater treatment plant could be successfully removed in the biofilter system, which may provide useful information concerning the design criteria and operation of full-scale biofilters. 相似文献
818.
在企业HSE管理的过程中,往往容易在危险源辨识、评价方法应用等方面存在一定的误区.笔者结合工作实际,谈几点肤浅的体会. 相似文献
819.
Matrix-bound phosphine in Antarctic biosphere 总被引:5,自引:0,他引:5
Phosphine (PH(3)) is a natural gaseous carrier of phosphorus in its geochemical cycles, and it might be of importance to the phosphorus balance of natural ecosystem. For the first time phosphine levels were investigated in the Earth's coldest, driest, and most southerly Antarctic biosphere. Matrix-bound phosphine (MBP) was found in sea animal guanos, ornithogenic sediments and soils. Phosphine concentrations varied with different sea animal guanos. Average phosphine concentrations in empire penguin, gentoo penguin, sea lion, skua and gull guanos were 2.54+/-1.28 ng kg(-1), 6.21+/-2.15 ng kg(-1), 9.12+/-4.66 ng kg(-1), 11.90+/-1.29 ng kg(-1) and 14.55+/-6.74 ng kg(-1), respectively. The contents of phosphorus in these various matrixes have an important effect on MBP concentrations. The levels of phosphine appeared an increasing tendency with the content of TP, IP and OP in sea animal guanos, ornithogenic sediments or soils. The correlation between PH(3) and Fe, Mn, Al in these matrixes was also analyzed and discussed. Phosphine showed an obviously positive correlation with Fe in sea animal guanos. However, excessively high Fe, Al and Mn may inhibit the formation of PH(3) in the ornithogenic soils or sediments in the Antarctic biosphere. 相似文献
820.
应用模式生物-秀丽隐杆线虫研究金属纳米镍的生殖发育毒性。采用20nm和90nm镍分别以2.5和5.0μg·cm-2两个剂量对秀丽隐杆线虫进行染毒,并以微米镍和生理盐水作对照,采用后代数目、世代时间、形态和体长、寿命和半数致死率等生殖发育相关评价指标,对纳米镍生殖发育毒性进行评价。结果发现,与生理盐水对照组和微米镍组比较,秀丽线虫暴露于20nm和90nm镍的两个剂量组后,均表现出生殖和发育的异常(P<0.01),并有剂量依赖性。且90nm镍暴露对秀丽线虫后代数目、世代时间、形态和体长、寿命和半数致死天数等指标的缺陷作用均显著于20nm镍。研究表明,纳米镍可影响秀丽线虫的生殖和发育功能,这一效应与纳米粒径和暴露浓度有关。此结论可为制定纳米镍的接触限值标准提供参考。 相似文献