黄河小浪底库区退化山地典型植物群落物种多样性分析

为探寻物种多样性与环境因子的关系,采用样地法分析了小浪底库区山地生态系统植物群落多样性指数,利用数学统计方法研究不同群落物种多样性指数与其所处环境的关系.结果表明,1)小浪底库区群落的物种多样性指数和丰富度指数与群落类型有密切关系;2)物种丰富度与海拔具有明显的负相关性,灌木的丰富度受海拔影响显著,而草本植物的丰富度与海拔的关系不显著;3)多样性指数H'、Pielou 均匀度指数Jsw与海拔表现出显著的负相关性;4)草本群落的Margalef丰富度指数D2随坡向有显著差异.表现出阴坡大于阳坡,其他指数随坡向没有显著性差异.     

四川重楼属药用植物资源研究

经调查鉴定,四川重楼属药用植物有10种7变种,均在我省民间广泛应用。目前川产商品重楼原植物有3种6变种,除中国药典收载的华重楼和滇重楼外,其分布广、产量大的还有七叶一枝花、狭小重楼和短梗重楼等3种4变种。     

应用淡水生物毒性数据推导海水水质基准的可行性及适用性初探

在海洋环境风险评价及环境标准与基准的制定中,由于海水生物毒性数据的欠缺,通常引入淡水数据加以补充,以此推导海水的预测无效应浓度(PNEC),但该方法所推导PNEC的"失真"程度目前尚未完全清晰。本研究选取了Pb、Cd、马拉硫磷和狄氏剂四种典型化合物,应用SSD模型方法比较分析了分别基于淡水生物和海水生物以及二者一并使用推导的PNEC值之间的差异性和相关性。结果发现:淡水生物与海水生物对各化合物响应的敏感性具有一定的差异。对于重金属,淡水物种可能对其胁迫更具敏感性,将淡水数据与海水数据一并使用所获得PNEC可有效的保护海洋生物;对于有机磷和有机氯农药,海水生物通常更具敏感性,淡水数据的介入和应用可能会对部分海洋生物造成部分"欠保护"现象,但总体上,淡水HC5与海水HC5二者相差不大,可通过适当的安全因子加以校正。     

转Bt基因水稻残留秸秆对农田底栖动物的影响

为研究转Bt基因水稻秸秆残留对稻田内底栖动物的潜在影响,利用转Bt基因水稻“华恢1号”及其亲本“明恢63”的秸秆进行稻田填埋试验,分析转Bt基因水稻秸秆中Bt蛋白对秸秆分解和底栖动物多样性的影响. 结果表明:①在填埋的水稻秸秆上共发现223个底栖动物,分属9个科,其中,在转Bt基因和非转基因水稻秸秆上均发现7个科. ②秸秆种类和秸秆填埋时间对底栖动物丰度、物种数、Shannon-Wiener多样性指数、辛普森优势集中性指数(Simpson diversity index)和Pielou均匀度指数均无明显影响. ③转Bt基因和非转基因水稻秸秆剩余率均随着填埋时间的延长而逐渐降低,填埋7周后,两种类型秸秆剩余率平均值均为44.0%,二者之间无明显差异. ④在填埋的7周内,转Bt基因水稻秸秆中w(Bt蛋白)平均值为1.99~3.04 μg/g,7周后为2.04 μg/g. 研究显示,稻田残留的转Bt基因水稻秸秆对底栖动物多样性无显著影响.      

外来物种入侵及其环境法律调控准则

随着世界经济、贸易和交通高度发达的影响，外来物种入侵活动且益加剧，已尼成为威胁我国生物多样性与生态环境的重要因素之一，对我国的一些地区造成了巨大的生态和经济损失。有关外来入侵物种管理的立法应贯彻风险预防原则。     

DOM的光化学活性及其对污染物光解的影响

溶解性有机质(dissolved organic matter,DOM)是自然水环境中重要的具有光化学活性的溶解性物质,是生态系统中碳循环的重要组成。DOM可以通过光化学转化生成多种活性物种,如激发三线态DOM、单线态氧、羟基自由基等,从而显著影响环境中重金属和有机污染物的光化学转化过程。该文综述了近些年关于DOM光致产生主要活性物种的机制及其对各种污染物光转化影响的研究进展,并对今后DOM的光化学研究提出了一些建议。     

甲萘威的淡水水生生物水质基准研究

为保护我国淡水水生生物,收集、筛选出5门23科44个物种的急性毒性数据和1门1科2个物种的慢性毒性数据,分别采用毒性百分数排序法和物种敏感度分布法,对我国甲萘威的淡水水生生物水质基准进行推导. 结果表明:我国淡水水生生物物种的急性毒性平均值范围为2.25～27 609 μg/L,甲壳纲急性毒性平均值范围为2.25～1 000 μg/L,鱼纲急性毒性平均值范围为700～27 609 μg/L,最敏感的物种为棘爪网纹溞,最不敏感的物种为胡鲶. 毒性百分数排序法推导出的基准最大浓度和基准连续浓度均为2.6 μg/L,物种敏感度分布法推导出的短期危险浓度和长期危险浓度分别为3.3和1.6 μg/L. 中美甲萘威的水质基准值差异归因于两国生物区系的不同. 甲壳纲对甲萘威的敏感度大于鱼纲. 初步统计表明,在22个天然水体样品中,有50%样品的甲萘威浓度高于淡水水质基准,存在环境风险.      

应用物种敏感度分布法研究中国无机汞的水生生物水质基准

基于中国的水生生物区系特征,筛选了包括植物、无脊椎动物和脊椎动物等90个水生生物的急性毒性数据,使用物种敏感度分布法探讨了各类物种的敏感度分布特征,推导了中国无机汞的水生生物水质基准.结果表明,甲壳类生物对无机汞最为敏感,Log-Slogistic3对各组数据拟合效果最佳.基于对全部数据的拟合结果,得出无机汞的急性水质基准和慢性水质基准分别是1.743和0.467μg.L-1.该基准值与其他国家使用类似统计外推法得到的基准值在同一数量级,但也存在着差异,反映了各国水生态系统物种组成的差异.中国无机汞水生生物水质基准的建立,旨在保护中国地表水生态系统中的水生生物免受无机汞的高浓度急性暴露以及低浓度慢性暴露产生的毒害效应.比较不同水体无机汞的浓度水平发现,除嘉陵江水体溶解态汞可能会对水生生物具有潜在风险外,西南地区地表水活性汞均不会对水生生物产生危害.     

Effects of fulvic acid and humic acid on aluminum speciation in drinking water

This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the e ects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L (calculated as TOC). Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5–7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the e ects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5–7.5 were recommended during drinking water treatment.     

Petroleum hydrocarbons and their effects on fishery species in the Bohai Sea, North China

Systematic studies on the changes in concentrations of petroleum hydrocarbons (PHs) and their e ects on fishery species in the Bohai Sea during 1974–2004 are presented. Changes in PHs concentrations were closely related to Yellow River runo . Concentrations of PHs accumulated in fish and shrimp increased by about 0.712 mg/kg dry weight when trophic level of fish and shrimps increased by 1. Attention should also be paid to the high PHs concentrations in mollusks along the coastal waters of the Bohai Sea. Average concentration of PHs in the adjacent coastal waters of Tianjin City during 1996–2005 decreased the population growth rates of fish, crustaceans and mollusks in the Bohai Sea by 2.58%, 6.59% and 2.33%, respectively. Therefore, PHs have significantly contributed to the decline in fisheries in the Bohai Sea, and they must be reduced to realize the sustainable fisheries.