海南岛西部地区砖红壤中微量元素含量及其分布特征

对海南岛西部地区发育典型的5个砖红壤剖面微量元素的组成特征进行研究发现,5个剖面微量元素的含量变化趋势具有一定的相似性,其中Cu、Pb、Zn、As平均含量大多高于中国南方砖红壤的平均值,而Ni、Mo、Cd、Sn、Sb等微量元素则刚好相反。各剖面微量元素含量的纵向变化规律显示,土壤中微量元素含量及其垂直变化从根本上取决于土壤母质的特征。受区内自然条件影响,区内土壤微量元素的垂向迁移能力相对较弱,而人类的工业活动、农业活动也可导致少量As、Cd、Pb等有害外源微量元素进入土壤并趋向于在土壤的浅层富集。     

园林植物挥发油成分分析及抗菌活性测定

运用试管稀释法和平板涂布法,测定黄皮,白皮松,香榧,侧柏,龙柏,雪松,圆柏等7种常见园林植物的挥发油对表皮葡萄球菌,金黄色葡萄球菌,大肠杆菌及绿脓杆菌的抗菌活性(包括抑菌和杀菌两个方面)。结果显示,所有供试植物挥发油均具有一定的抗菌活性。对金黄色葡萄球菌的抑菌活性为侧柏=龙柏>圆柏>雪松>香榧;对表皮葡萄球菌的抑菌活性为侧柏>圆柏>龙柏=雪松=黄皮>白皮松>香榧;仅圆柏挥发油对大肠杆菌具有抑菌作用,所有供试植物挥发油对绿脓杆菌均无抑菌作用。实验证明,圆柏,侧柏,龙柏,雪松具有较强抗菌活性,是较为理想的城市生态保健型绿化模式的栽培树种。     

工业废水对洹河有机污染的调查与分析

采用适当的样品前处理技术,利用GC/MS对洹河水及焦化厂、染料厂废水进行有机污染物的分析,确定了工业废水对洹河造成有机污染的主要化合物,从而为企业污水的处理和洹河治理提供依据.     

胶体态有机物对生物膜硝化过程的影响

利用曝气生物滤池研究了胶体态和溶解态有机物对生物膜中硝化过程的影响.实验结果表明,胶体态有机物的水解过程进行得较为迅速,不会成为生物降解的限制过程.70%有机物的氧化在滤池的进口40cm内完成,而随着进水有机物浓度的增加硝化过程向滤池的上部迁移.胶体态有机物对硝化过程的抑制作用比同样浓度溶解态有机物略大.     

6种挥发性有机物在甲苯驯化微生物中的好氧生物降解性能

利用振荡摇瓶法测定了6种典型挥发性有机物,甲苯、邻二甲苯、间二甲苯、对二甲苯、苯和氯苯在甲苯驯化微生物中的好氧生物降解性能.结果表明,在本研究的液相浓度范围内(甲苯＜174mg/L,邻二甲苯＜149mg/L,间二甲苯＜129mg/L,对二甲苯＜133mg/L,苯＜234mg/L,氯苯＜146mg/L),3种二甲苯、苯和氯苯的降解速率随其初始浓度的增大而增加,符合一级反应,这5种VOCs未对微生物产生明显的抑制或毒害作用;甲苯的液相浓度大于85mg/L时,其降解速率不随初始浓度的增大而改变,其降解规律符合Monod方程.     

西太湖秋季蓝藻水华过后细胞裂解对溶解性有机碳影响

从2009年7月~2010年3月每月采集西太湖表层水样,分析叶绿素含量﹑蓝藻细胞裂解速率﹑磷酸盐浓度的变化,并通过切向流超滤系统分离得到的高分子量(1kDa~0.5μm)溶解性有机物的碳氮比值和高分子量溶解性有机碳浓度的变化.结果表明,西太湖蓝藻细胞裂解速率在11月达到最大值(0.43d-1),而磷酸盐和高分子量溶解性有机碳浓度分别在12月与9月达到最大值.细胞裂解速率与磷酸盐﹑高分子量溶解性有机碳浓度之间没有相关性,说明水华过后影响磷酸盐浓度﹑高分子量溶解性有机碳的因素很多,蓝藻细胞裂解只是其中重要因素之一.藻类水华的出现可能导致水体中其它磷形态(如有机磷)与磷酸盐之间的迁移转化,而大型浅水湖泊扰动导致的沉积物再悬浮和水华过后频繁的细菌活动都可能是影响高分子量溶解性有机碳的因素.秋季水华过后蓝藻细胞裂解释放的有机碳进入微食物网循环,引起细菌活动频繁,而溶解性有机物中含碳化合物比含氮化合物容易降解,所以碳氮比值逐渐减少.此外细菌通过硝酸盐合成溶解性有机氮也可能是碳氮比值减少的一个重要原因.     

高温碱间歇式处理对互花米草厌氧发酵特性的影响

以互花米草为原料,采用中温(35±1)℃批式发酵的方式,考察了NaOH高温碱间歇式处理对互花米草厌氧消化过程的影响.结果表明,互花米草一次发酵至产气停止,单位TS产气量为263mL/g,发酵过程中出现酸化现象, pH值最低为5.17.二次发酵原料为一次发酵后的固体残余物,主要组分为可分解有机物以及一些难分解有机物,过程中未出现酸化现象, pH值经短暂下降后很快稳定在7.5左右,累积产气量在一次发酵的基础上提高了46%.互花米草单位TS产气量为383mL/g.消化液中有机酸乙酸含量最大,丙酸和丁酸含量相当.     

厦门汀溪水库溶解有机氮对有毒藻种的生物有效性及其化学本质

为探究厦门汀溪水库溶解有机氮(DON)对有毒藻种的生物有效性及其化学本质,采用水样分子质量和极性分级技术,进行铜绿微囊藻 (Microcystis aeruginosa)培养实验.结果表明,汀溪水库中DON含量呈季节性差异,在枯水期比较高,而丰水期比较低.汀溪水库DON在不同季节中的主要成分都是疏水组分和>3kDa组分.汀溪水库DON的生物有效性为65.20%.较疏水组分和>3kDa组分而言,亲水组分和￡3kDa组分DON更易被铜绿微囊藻利用.从水环境和水源保护角度出发,应首先考虑消除DON中的亲水性组分和小分子质量组分.     

Effects of repeated pesticide exposure on the peripheral and central nervous systems

This study was designed to compare organic farmers (comparison group) and pesticide-using farmers (pesticide group) in terms of neurobehavioral performance and sensorimotor function. The subjects were recruited in October 2004 from Chungnam Province and the neighboring Jeolla Province in western South Korea. Psychological assessment was carried out using the Wechsler Adult Intelligence Scale, the Mini-Mental State Examination, and the Bender Gestalt test. Neuroselective sensory nerve conduction threshold was measured at both left and right middle fingers by using an electrodiagnostic device to determine current perception thresholds (CPTs). Three independent CPT measurements were obtained from each test site by using sinusoidal stimuli at three frequencies. CPT testing showed no difference between the two groups. No significant differences were found in the large myelinated (2000?Hz stimulation; cutaneous touch, pressure), small myelinated (250?Hz stimulation; mechanoreceptive, pressure, temperature, fast pain) and small unmyelinated (5?Hz stimulation; polymodal nociceptive, temperature, slow pain, postganglionic sympathetic) C-fibers. Furthermore, there was no difference found between the pesticide and comparison groups in psychological variables, including intelligence quotient, orientation, memory, calculation, similarities, visual sensitivity, and psychomotor speed. In conclusion, chronic pesticide exposure has no apparent effect on either the peripheral or central nervous system in Korean farmers.     

Employment of passive sampling in monitoring indoor air quality in selected residences in a Tri-city area in Poland

Time-weighted average concentrations of selected volatile compounds were measured in chosen residences in a Tri-City area of Poland by means of passive sampling. The results were compared to those obtained by dynamic technique – sorption tubes filled with Tenax TA sorbent. Results obtained by employing the two techniques were similar. Total volatile organic compound (TVOC) parameters were also determined. An attempt was also made to evaluate the influence of outdoor air pollutants on indoor air quality.