Distribution of Pb,Cr, Cu and Zn in the marine-coastal region of Zanzibar (Tanzanian archipelago,East Africa)

In Tanzania, a large amount of domestic and industrial wastes are daily released to the aquatic environment without prior treatment. The present paper establishes the status of distribution and environmental implications of heavy metals in water, sediment, suspended particulate matter and biota (Anadara antiquata) from two marine coasts in Zanzibar, Tanzania. These metals are derived from the industrial areas through rivers and storm water outflows. Heavy metal concentrations in the collected samples were determined using atomic absorption spectrophotometry. Concentrations were significantly higher in the Malindi compared to the Fumba coast (ANOVA, p?=?.001). Calculation of metal partition coefficients shows that the relative importance of the particulate and the water phases varies in response to water parameters and suspended solid content, but that most elements achieve a conditional equilibrium in these coasts. Higher metal concentrations found in Malindi suggest a pollution effect related to anthropogenic activities. Mean metal burdens in the tissues of A. antiquata from both Malindi and Fumba coasts were significantly higher than in other compartments analysed (ANOVA, p?<.05). Maximum values of contamination factor and contamination degree for metals were noticed for sediments from both Malindi and Fumba coasts. It is imperative to understand that metal concentrations of coastal environments depend not only on industrial and household waste inputs but also on the geochemical composition of the area.     

基于因子分析的开采层瓦斯抽采方法选择

基于煤与瓦斯的七个基本参数,应用因子分析方法,得到了反应本煤层抽放难易程度、突出危险性及瓦斯涌出量(不考虑邻近层影响)的三个因子。依据因子得分对开采层瓦斯抽放难易程度及煤与瓦斯突出危险性进行了分类,进而对开采层瓦斯预抽方法进行判断。结果表明,采用因子分析的方法进行开采层瓦斯预抽方法的选择与现场抽放设计基本一致,并且对于传统方法无法分类的情况也给出了合理的分类判断。采用该方法可以较客观、合理的选择开采层瓦斯抽采方法。     

天津冬季相对湿度对气溶胶浓度谱分布和大气能见度的影响

于2013年1月连续在线观测天津城区气溶胶数浓度谱分布和大气能见度,并结合相关气象资料,探讨相对湿度(RH)对气溶胶浓度谱分布和大气能见度的影响.结果表明,观测期间发生了4次连续雾霾天气过程, 4次雾霾天气过程对应着气溶胶粒子数浓度的连续高值,低能见度天气系高浓度气溶胶粒子和高相对湿度协同所致;随着RH增大,PN1和PN2.5-10呈增长趋势, RH>90%后,PN1和PN2.5-10有所降低,PN1-2.5则持续增长,高RH对气粒转化和气溶胶粒子的碰并聚合作用明显;气溶胶吸湿增长因子计算表明,高RH下水汽对能见度影响很大,尤其是大雾天气下其影响甚至可能超过气溶胶粒子浓度对其的影响.     

岩溶区城市建设地面塌陷易发性研究——以井冈山市新城区岩溶地面塌陷为例

井冈山市新城区位于一岩溶向斜盆地中部,上覆第四系松散层,下伏强岩溶化碳酸盐岩类．地下水径流活动强烈．存在岩溶地面塌陷的可能性。由于覆盖型岩溶区的地面塌陷灾害具隐蔽性、突发性、危害性．因而对新城区岩溶地面塌陷进行预测分析是十分重要与必要的。文中通过对现有地面塌陷点的成因分析,了解区段塌陷形成的主要因素,结合岩溶塌陷的各影响因素．采用定性一半定量方法对新城区覆盖型岩溶区进行岩溶塌陷初步预测：新址大部分地区属岩溶塌陷少发区,是适宜城市建设的。     

土层地震反应分析的地面加速度峰值计算研究

针对不同的工程场地采用20组相互独立的基岩加速度时程作为输入地震波,对广东省307个项目的地震安全性评价中的662个地震钻孔剖面进行土层地震反应分析,用相对均方误差来定量评估所得到的地面加速度峰值离散值,发现地面加速度峰值的计算结果具有很大的离散性,最大相对均方误差为19%,平均相对均方误差为7.53%;地震基本烈度高的地区比地震基本烈度低的地区的相对均方误差大,场地类别差的比场地类别好的相对均方误差大;目前较为普遍地用1条或3条基岩加速度时程作为地震动输入是明显不够的,应适当地增加,对于高烈度地区和场地类别较差的场地更是如此,才能得到较为合理的地面加速度峰值。     

气候对我国城市居民氟摄入量的影响

对中国19个城市的供水氟含量与当地居民尿氟含量进行了检测,并对检测当月的平均气候资料和口腔健康资料与之进行相关分析。研究表明,低于18℃的月平均气温对我国城市居民氟的摄入量基本没有影响;当月平均气温高于18℃时,随着气温的升高,我国城市居民氟的摄入量会随饮水量的增加而上升,反映了我国城市居民主要依靠饮用水摄取氟。对于平均相对湿度来说,月平均相对湿度超过80%会对我国城市居民氟的摄入量产生影响。     

闽江流域福州区段肠道病毒污染程度的监测与预测

为了解闽江流域福州区段肠道病毒污染状况,病毒污染水平与某些水质因子的相关性,以期建立用简单的方法对水体病毒污染程度进行预测,1998年11月-2000年4月,监测了闽江下游福州段水体肠道病毒污染与水质状况.结果显示,肠道病毒阳性率71.1%,平均病毒浓度5.33pfu/L,其中3个污染控制断面肠道病毒阳性检出率及病毒浓度显著高于对照和削减断面.这表明闽江福州段水环境病毒污染水平同福州市内河生活污水排放有直接的关系,而内河引水冲污工程的实施显然又加剧了闽江水病毒污染程度,增加了饮用水的卫生微生物学危险性.逐步回归分析结果显示,不同水样点的病毒浓度与一定的水质理化和生物因子间有显著性的线性关系,可用于水体环境病毒污染状况及危害程度的简单预测.     

长江三角洲与苏北海岸动态类型划分及侵蚀危险度研究

利用统计分析模型对长江三角洲与苏北海岸动态类型及海岸侵蚀灾害危险度进行了初步研究。首先根据形态一致性将该区域海岸划分为21个岸段,选取年平均高潮位、潮滩宽度、潮滩平均坡度、平均高潮位以上潮滩滩高、0－5m海水年平均含沙量,年淤进率,年蚀退率,年下蚀率,年积高率和潮滩年沉积量等10个变量描述海岸潮滩动力、形态和演变特片,利用因子分析和聚类分析,提取共通性变量,综合反映潮滩的自然特征,对海岸进行定量化类型划分,并根据各岸段主成分得分评价各岸段海岸侵蚀的危险度。     

煤矿运输安全性的灰熵综合评价

基于灰熵理论,提出一种新的安全性评价方法即灰熵综合评价。灰熵是离散序列均衡程度的测度,灰色关联度是参考序列和比较序列之间接近程度的测度。该法将灰色关联度和均衡度合成为均衡接近度,并以此作为评价准则,从而避免了低层次多因素权重确定的主观性,使评价模型更加合理,评价结果更加客观。通过利用多层次灰熵综合评价模型,对平顶山煤业(集团)有限责任公司六矿运输系统的安全性进行综合评价,其结果表明,该方法较其他评价方法更加客观,结论更符合实际,同时指出了今后运输安全管理工作的重点。     

Cell-recycle fed-batch production of a highly unsaturated polyhydroxyalkanoate from 1,3-butanediol byPseudomonas sp. A33

The recently isolatedPseudomonas sp. A33 was investigated for the production of a highly unsaturated polyhydroxyalkanoate (PHA) containing various alkyl and alkenyl pendent groups from 1,3-butanediol in a cell-recycle fed-batch production mode. The monomer composition and degree of unsaturation in PHA were dependent on the environmental conditions. The production temperature markedly influenced the content, composition, and degree of unsaturation of PHA. As the production temperature decreased from 30 to 10°C, the degree of unsaturation and content of PHA were increased, while the mole percentage of 3-hydroxybutyrate (3HB) was decreased. These temperature effects on the composition of PHA imply that the production can be used as a control variable for the biosynthesis of a highly unsaturated PHA and for the specific regulation of the composition of PHA. The biosynthetic pathway for a highly unsaturated PHA which is based on de novo fatty acid biosynthetic pathway is proposed. For the enhanced production of this functional PHA, a high cell density was achieved by cell-recycle continuous culture at 30°C, and then a large amount of PHA was accumulated at 15°C by fed-batch addition of the feeding solution containing excess 1,3-butanediol. The structures of monomer constituents of polymer were confirmed by gas chromatography—mass spectrometric analysis of trimethylsiyl derivatives of 3-hydroxyalkanoic acids methyl esters.