监测水体重金属污染的分子生物标志物研究进展

水体重金属污染具有持久性、高度危害性和难治理性,如何快速、准确监测并对其进行科学评价,成为当今环境科学关心的热点问题。大量研究表明,水生生物体内某些生理指标的变化可以反映水体重金属的污染程度。综述了乙酰胆碱酯酶、抗氧化防御系统、腺苷三磷酸、DNA损伤以及金属硫蛋白等几种分子水平上的生物标志物监测重金属污染的原理、国内外研究进展以及应用现状。认为分子生物标志物具有特异性、敏感性等优势,可以较快指示水体重金属污染对生物体的影响,在实际应用中需注意各种干扰因素。在进行野外研究时,要注重混合重金属与多途径暴露下,分子生物标志物的变化规律。生物体之间差异性会导致标志物在同样暴露条件下产生不同的变化规律,需要加强＂离体＂标志物和＂标准化＂标志物的研究,确保监测结果的可靠性和可重复性。生物标志物较为敏感,容易受到外界环境及体内生理因素影响,可考虑综合运用多种生物标志物指示重金属污染。目前,有关重金属对水生生物毒性效应的研究较多,但重金属对生物体的致毒机理方面研究并不深入,这将是今后研究的重点问题之一。     

均压和封堵措施在运河煤矿中的应用

结合运河煤矿综放工作面的特点,对工作面漏风通道进行了分析。通过实施均压和封堵两项综合措施,不但解决了工作面向采空区漏风的问题,而且抑制了采空区瓦斯向工作面的涌出,有效地保证了工作面的安全开采。     

高级氧化技术治理钻井废水的研究

以油气田现场钻井废水为研究对象,对经过物理化学脱稳、机械分离后的废水进行O3预氧化-中间混凝-O3/H2O2深度氧化工艺.着重考察了该工艺中的体系pH值、O3/H2O2的加量比例、反应时间等工艺条件.找出了最佳的条件,在最佳条件下的出水CODcr为142 mg/L,去除率高达96.7%,已达到国家二级排放标准.     

印染废水治理方案分析

某针织印染厂年产3000吨针织高档服装布料,排放的生产废水中含有大量的有机物,COD、BOD5、色度浓度比较高。该厂选择了"厌氧水解酸化+接触氧化法+活性炭吸附"处理工艺。该工艺采用厌氧水解酸化处理工艺进行前期处理,去除大部分有机物,减轻了后续接触氧化处理工艺的压力,同时通过活性碳过滤进行脱色,达到较好的处理效果。运行结果表明,经该工艺处理后,废水中的COD、BOD5、色度等指标均能达标排放,有利于企业的可持续发展。     

Allelopathic inhibition on red tide microalgae Skeletonema costatum by five macroalgal extracts

This study aims to identify effective antialgal allelochemicals from marine macroalgae that inhibit the growth of red tide microalgae. Practically, new algicidal agents were developed to control red tide. The growth inhibitory effects of 5 marine macroalgae Porphyra tenera, Laminaria japonica, Ulva pertusa, Enteromorpha clathrata, and Undaria pinnatifida on Skeletonema costatum were evaluated by adding crude seawater extracts of macroalgal dry tissue into the culture medium containing S. costatum. The half-effective concentrations at 120 h (EC_{50, 120 h}) of the seawater extracts were 0.6, 0.9, 1.0, 1.0, and 4.7 g/L for the five macroalgae above, respectively. E. clathrata, L. japonica and U. pertusa showed strong allelopathic effect on the growth of S. costatum. There have been no previous reports with regard to the allelopathic effects of the former two macroalgae so far. The possible allelochemicals of 21 compounds of the E. clathrata were detected using Gas chromatography-mass spectrometry (GC-MS) analysis. Unsaturated fatty acids, acrylic acid (C₃H₄O₂), and linolenic acid (C₁₈H₃₀O₂) were the most likely allelochemicals in E. clathrata.     

Impact of urbanization on natural ecosystem service values: a comparative study

With rapid population growth and rural to-urban migration in many Chinese cities, a large amount of natural lands have been converted to urban and agricultural lands recently. During this process of land conversion, economic development and quality of life improvement are considered as major goals, and their influences on ecological systems have often been neglected. The degradation of natural ecological systems due to land use change, however, has become severe,and may require immediate attentions from urban planners and local governments. Taking HaDaQi industrial corridor, Heilongjiang Province, China,as a case study area, this paper examined the trend of land use changes during 1990–2005, and quantified their influences on natural eco system service values. In particular, this study applied two major valuation methods, and examined whether different valuation methods generate significantly different results. Analysis of results suggests that human dominated land uses (e.g., urban and agriculture)have expanded rapidly at the cost of natural lands (e.g., wetlands and forest). Due to these land use changes, the total ecosystem service value decreased 29% (2.26% annually) from 1990 to 2005 when the first method was applied, and this rate is estimated to be 15.7% (1.13% annually)with the second approach. Moreover, the annual rate of ecosystem service value decline during 2000–2005 is about four times higher than that in 1990–2000 with both methods, suggesting much more severe ecosystem degradation during 2000–2005.     

鸟粪石沉淀法处理沼液实验研究

以MgCl2·6H2O和KH2PO4·12H2O为沉淀剂,开展了鸟粪石沉淀法处理沼液实验,研究了沉淀剂投加量、反应过程中pH值对沼液中氦氮、总磷去除效果的影响.研究表明,在pH值为9、Mg2+:PO4-3:NH4+=1.1:1.05:1(摩尔比)时,出水中氨氮为45.mg/L、总磷为15mg/L,脱氟除磷综合效果最佳.     

内流激发垂直悬臂管振动失稳特性实验研究

目的 研究管道内部流速和浸没深度对细长柔性悬臂管道振动特性的影响规律。方法 通过位移传感器采集管道振动位移时程,计算管道振幅、时频特性、相位变迁和振动频率,分析内流在输流过程中所激发的管道振动失稳特性。结果 随着内流流速的增加,垂直悬臂管会经历静态、前失稳和后失稳3个不同状态。管道振幅随内流流速的增加而明显增大,但振动频率只是缓慢上升。随着管道浸没深度的增加,管道振动失稳整体减弱。结论 内流流速和浸没深度均是影响管道振动失稳特性的关键因素。     

磺胺嘧啶对鱼菜共生系统氮元素转化的影响

本文研究了典型抗生素磺胺嘧啶对实验室规模鲤鱼-小白菜共生系统生产性能和氮元素转化的影响.结果表明,磺胺嘧啶使系统鲤鱼体重增量提高17%,但小白菜生产性能大幅下降,使得系统氮素利用率由43.66%降至21.20%,N₂O转化率由1.02%上升至1.98%.磺胺嘧啶在投加初期对系统的硝化过程表现出短期抑制效应,经过32d的适应期后,实验组氨氮浓度下降至和对照组相近水平,系统运行后期实验组氨氧化细菌丰度相较对照组提高51.43%.鱼体内残余的磺胺嘧啶为35.23μg/kg,符合国家标准,但水体中磺胺类药物抗性基因sul1、sul2及intI1的拷贝数分别提升至7.23倍、2.74倍和4.12倍.从生产性能及环境友好性考虑,鱼菜共生系统在设计及运行中应减少或避免抗生素的使用,并采取合理的替代措施规避其风险.     

多元复合调理剂对镉砷污染农田土壤微生物群落结构的影响

通过温室盆栽试验,研究多元复合调理剂（石灰石、铁粉、硅肥和钙镁磷肥,简称LISP）对土壤基本理化性质、Cd和As的生物有效性和微生物群落结构的影响.结果表明,LISP可改变土壤基本理化性质,降低土壤有效态Cd和As含量,并改变土壤微生物群落结构.在0.4%的LISP添加下,土壤pH值、有效磷和总磷含量较CK处理分别显著（P< 0.05）提高0.57单位、130.6%和18.38%,同时土壤有效态Cd和As含量较对照分别显著（P< 0.05）降低21.76%和16.39%.高通量测序结果表明,添加LISP可维持污染土壤中正常微生物群落的多样性和丰富度,而显著改变土壤微生物群落的组成和结构,其中厚壁菌门、放线菌门和浮霉菌门等门水平物种的相对丰度增加,而绿弯菌门、酸杆菌门和疣微菌门等门水平物种的相对丰度降低.冗余分析和Mantel检验分析表明,土壤pH值、有效磷以及有效态Cd和As含量是影响土壤微生物群落结构的主要环境因子.上述结果表明,LISP是一种有效的、生态安全的调理剂用于农田土壤Cd和As污染土壤修复.