Field evaluation of in situ remediation of a heavy metal contaminated soil using lime and red-mud

We evaluated the effectiveness of lime and red mud (by-product of aluminium manufacturing) to reduce metal availability to Festuca rubra and to allow re-vegetation on a highly contaminated brown-field site. Application of both lime and red mud (at 3 or 5%) increased soil pH and decreased metal availability. Festuca rubra failed to establish in the control plots, but grew to a near complete vegetative cover on the amended plots. The most effective treatment in decreasing grass metal concentrations in the first year was 5% red mud, but by year two all amendments were equally effective. In an additional pot experiment, P application in combination with red mud or lime decreased the Pb concentration, but not total uptake of Pb in Festuca rubra compared to red mud alone. The results show that both red mud and lime can be used to remediate a heavily contaminated acid soil to allow re-vegetation.     

反硝化生物膜对PBS表面形态及化学组分的影响

PBS是一种新型的可生物降解聚合物(BDPs),可以用做反硝化碳源和生物膜载体,去除饮用水源水中的硝酸盐.利用红外光谱和扫描电子显微镜对反硝化生物膜生长前后PBS颗粒表面形态、化学组成的变化进行了分析.结果表明,PBS仅在微生物作用下降解并为反硝化菌提供碳源.PBS颗粒可以在12 h内使进水中53 mg·L^-1的硝态氮降低到10 mg·L^-1以下(我国饮用水水质标准为:NO₃^--N<15 mg·L^-1).红外光谱表明,反硝化微生物附着生长后其PBS在2 925 cm^-1和2 850 cm^-1附近的吸收带以及3 200 cm^-1～3 410 cm^-1处峰值减弱,说明PBS材料中甲基、羟基官能团比例下降,而其它官能团没有发生明显的变化,PBS的主要单体组分淀粉和乙烯都可以被反硝化微生物用作碳源.扫描电子显微镜观察结果表明,反硝化生物膜附着生长后,PBS颗粒表面会出现空洞,扩大了生物膜生物附着生长的表面积,有利于形成致密的反硝化生物膜,对反硝化菌形成保护作用.     

Variations of bacterial community structure in flooded paddy soil contaminated with herbicide quinclorac

The denaturing gradient gel electrophoresis (DGGE) method was applied to determine the relative genetic complexity of microbial communities in flooded paddy soil treated with herbicide quinclorac (3,7-dichloro-8-quinoline-carboylic acid). The results obtained showed a significant effect of quinclorac on the development of bacterial populations in soils contaminated with different concentrations of the herbicide at the early time after application. In general, however, the number of populations of the same soil sample treated with the same concentration of the quinclorac differed obviously with increasing incubation time within the early 8 weeks. The scale of differences in banding patterns-showed that the microbial community structures of the quinclorac-treated and non-quinclorac-treated soils were not significantly different after 21 weeks of incubation. Quantification, as demonstrated in this paper, was studied by establishing dose-response relationships. Significant pattern variations were quantified. Prominent DGGE bands were excised, cloned and sequenced to gain insight into the identities of predominant bacterial populations. The majority of DGGE band sequences were related to bacterial genera Clostridium, Sphingobacterium, Xanthomonas and Rhodococcus.     

Effects of sulfur dioxide and nitric oxide on mercury oxidation and reduction under homogeneous conditions

This paper is particularly related to elemental mercury (Hg0) oxidation and divalent mercury (Hg2+) reduction under simulated flue gas conditions in the presence of nitric oxide (NO) and sulfur dioxide (SO2). As a powerful oxidant and chlorinating reagent, Cl2 has the potential for Hg oxidation. However, the detailed mechanism for the interactions, especially among chlorine (Cl)-containing species, SO2, NO, as well as H2O, remains ambiguous. Research described in this paper therefore focused on the impacts of SO2 and NO on Hg0 oxidation and Hg2+ reduction with the intent of unraveling unrecognized interactions among Cl species, SO2, and NO most importantly in the presence of H2O. The experimental results demonstrated that SO2 and NO had pronounced inhibitory effects on Hg0 oxidation at high temperatures when H2O was also present in the gas blend. Such a demonstration was further confirmed by the reduction of Hg2+ back into its elemental form. Data revealed that SO2 and NO were capable of promoting homogeneous reduction of Hg2+ to Hg0 with H2O being present. However, the above inhibition or promotion disappeared under homogeneous conditions when H2O was removed from the gas blend.     

利用百合(Lilium davidii)根尖细胞的微核细胞率作为环境监测指标的探讨

首次报道了利用百合根尖细胞微核细胞率作为环境监测指标的可行性和优越性。实验证明,百合根尖比蚕豆根尖细胞的微核细胞率更敏感。     

企业实用安全评价方法初探--一种简单易行的企业自我评价方法

分析了当前我国安全评价中存在的问题,探讨一种企业实用的安全综合评价方法.介绍该方法的评价原理、程序和步骤,总结该评价方法的功能、特点和适用范围,提出改进方向.     

丹江口水库总氮较高原因初步分析

通过对丹江口水库库区、河南省辖入库河流及其它水体含氮类指标的对比,对水库总氮偏高的原因加以分析,指出总氮标准与硝酸盐、氨氮标准有差异,提出合理评价总氮指标及水库水质、加强水质保护措施的建议。     

芦笛·芦叶·芦花

早春二月,与小草一起先绿起来的要数河滩上的芦苇了。一场春雨过后,芦苇就像竹笋一样直往上窜,一天一个样子,好似在一夜之间,河边的芦苇长得就有人高了,这时河滩上是我们玩耍最多的地方。 从河滩上传出的除了我们的阵阵笑声外,就是我们吹出的没有一点节奏的芦笛声了。最初吹出的芦笛声只有自己才能听到,现在想起来那种声音也不知算不算是芦笛的声音。那时的芦苇刚刚冒尖不久,我们抽出芦苇中间嫩嫩的芦     

海底大地震

您以为只有陆地才经常发生地震吗?不,在深深的海底,也经常发生地震。据统计,全球80％的地震都集中在幽深的海底,特别是在太平洋周围海洋平均深度4000米以上,终年暗无天日的海沟里以及它附近与群岛区的深渊中尤为多见。     

图书馆消防安全--重中之重

尽管公共场所建筑物的消防安全历来是一个重要问题,国家每年都要投入很大的人力、物力来加强预防措施以避免出现人员及财产的重大损失,但终日警钟长鸣也还是存在缝隙,仅最近一个时期,各地就连续出现公共建筑物失火伤人的重大事故。因此,日常的防微杜渐工作是十分重要的。