三峡库区重庆段鲶鱼和鲤鱼体内持久性有机污染物分析

为了了解三峡库区重庆段水体中持久性有机污染物的生物富集情况,对该水体部分鱼类样品进行了分析。分析结果显示三峡库区重庆段水体中的部分持久性有机污染物已经在鲶鱼和鲤鱼体内形成富集,其检出浓度较之水体中对应浓度要高出2~4个数量级。     

巢湖流域蒸发量特征及变化趋势研究

巢湖作为安徽省境内的一个重要湖泊，对安徽省生态环境起到一定的影响作用。蒸发量是影响生态环境的重要因子，在很多方面是该区生态环境的一个反映。采用了统计学方法，对巢湖流域15个蒸发点20年（1981-2000年）的资料进行了分析，初步探讨了巢湖流域的蒸发量空间分布特征与地势、气温、风速、降水量等因子的关系，以及蒸发量在1年内的变化特征和年际变化趋势，试图说明研究时段内人类活动对区域蒸发量的影响。研究表明，由于地形等因素的影响，巢湖流域的蒸发量空间分布不均衡，在研究时段内蒸发量大体呈上升趋势。     

一维粘性泥石流运动的格子Boltzmann模拟

利用格子Boltzmann方法,对一维粘性泥石流的运动进行了定量化研究和数值模拟,为进一步研究泥石流的运动机制奠定了基础。在模拟一维粘性泥石流运动时,采用了含外力项的格子Boltzmann模型,通过对外力因子、平衡态分布函数的构造,使得宏观统计特性刻画了泥石流运动的非线性特征,成功模拟了泥石流的运动过程,获得了泥石流水深、流速两大要素的时空变化规律,为研究泥石流运动过程提供了一种新手段。     

投加EM菌处理垃圾渗滤液的试验研究

向污泥中投加EM菌处理高浓度垃圾渗滤液,以常规的微生物处理为对照.以COD为考察目标,探讨了在好氧条件下处理时,各种条件因素(温度、时间、pH、污泥负荷等)对处理效果的影响以及投加EM茵对处理出水COD分子量分布的影响.结果表明,在一定的好氧条件下处理渗滤液时,试验组和对照组的处理效果差异显著.试验组在最佳的好氧条件下可使COD的去除率达到72.5%,高于对照组26.3%.在好氧条件下处理渗滤液.试验组出水中小分子COD的比例高于对照组.     

北美自由贸易区和欧盟的环境政策：趋向,启示与对策

以北美自由贸易区和欧盟为代表的区域性经济集团已在经济利益与环境保护挂钩的制度性安排方面取得诸多进展，它们不同程度地在机构设置、协定条款、资金安排等方面强化了环境要求，并在国际环境公约的执行上表现出积极、灵活的特点。这一切都将为未来多边经济体系中环境问题的协商和解决开辟了新的途径， 也为我国在实施可持续发展过程中的环境制度化建设提供可鉴之处。     

Mobility and sulfidization of heavy metals in sediments of a shallow eutrophic lake, Lake Taihu, China

The technique of DGT (diffusive gradients in thin films) using three diffusive gel thicknesses was applied to estimate the mobility and bioavailability of heavy metals in sediments and porewater of Lake Taihu, China. The DGT results showed significantly positive correlations between Co, Pb, Cd and Mn, and Ni and Fe concentrations in porewater. Cu and Zn showed a significantly negative correlation with Mn, due to Cu combination with carbonates and Zn derived from agricultural pollution, respectively. The rank order of average concentrations of Co, Ni and Cd at each station was DGT_1.92 > DGT_0.78 > DGT_0.39, suggesting stronger resupply from sediments to porewater when using thicker diffusive gels. Comparing centrifugation and DGT measurements, Co, Ni and Cd are highly labile; Mn and Fe are moderately labile; and Cu, Zn and Pb are slightly labile. The variations of AVS concentrations in sediment cores indicate that metal sulfides in deeper layers are easily diffused into surface sediments.     

腐殖酸与镉离子在水合二氧化锰表面的分配系数研究

水体中腐殖酸(HA)和金属离子广泛存在,二者的相互作用对其在水中天然矿物颗粒表面的吸附、降解等环境行为具有重要影响.本文采用离子交换平衡法测定了HA和镉离子(Cd(Ⅱ))的配位数(co-ordination number,x)和络合稳定常数(complex stability constant,K),系统考察了pH值和离子强度对x和K的影响,并研究了HA和Cd(Ⅱ)在水合二氧化锰(HMO)表面的分配关系.结果表明:pH值对HA和Cd(Ⅱ)的配位数影响较小(x=1.651~1.752),而对络合稳定常数影响显著(log K=1.652~3.548);在不同pH值条件下,离子强度对HA和Cd(Ⅱ)的络合稳定常数影响均较小,而其配位数均随溶液离子强度的增加而提高;不同温度条件下,HA-Cd(Ⅱ)络合物在HMO表面的分配系数(Kd)均低于HA和Cd(Ⅱ)在HMO表面的分配系数,表明HA-Cd(Ⅱ)络合体系的存在抑制了HMO对Cd(Ⅱ)和HA的去除作用.     

Controlling cyanobacterial blooms by managing nutrient ratio and limitation in a large hypereutrophic lake: Lake Taihu, China

Excessive nitrogen (N) and phosphorus (P) loading of aquatic ecosystems is a leading cause of eutrophication and harmful algal blooms worldwide, and reducing nutrient levels in water has been a primary management objective. To provide a rational protection strategy and predict future trends of eutrophication in eutrophic lakes, we need to understand the relationships between nutrient ratios and nutrient limitations. We conducted a set of outdoor bioassays at the shore of Lake Taihu. It showed that N only additions induced phytoplankton growth but adding only P did not. Combined N plus P additions promoted higher phytoplankton biomass than N only additions, which suggested that both N and P were deficient for maximum phytoplankton growth in this lake (TN:TP = 18.9). When nutrients are present at less than 7.75-13.95 mg/L TN and 0.41-0.74 mg/L TP, the deficiency of either N or P or both limits the growth of phytoplankton. N limitation then takes place when the TN:TP ratio is less than 21.5-24.7 (TDN:TDP was 34.2-44.3), and P limitation occurs above this. Therefore, according to this ratio, controlling N when N limitation exists and controlling P when P deficiency is present will prevent algal blooms effectively in the short term. But for the long term, a persistent dual nutrient (N and P) management strategy is necessary.     

Mobility and sulfidization of heavy metals in sediments of a shallow eutrophic lake,Lake Taihu,China

The technique of DGT (diffusive gradients in thin films) using three diffusive gel thicknesses was applied to estimate the mobility and bioavailability of heavy metals in sediments and porewater of Lake Taihu, China. The DGT results showed significantly positive correlations between Co, Pb, Cd and Mn, and Ni and Fe concentrations in porewater. Cu and Zn showed a significantly negative correlation with Mn, due to Cu combination with carbonates and Zn derived from agricultural pollution, respectively. The rank order of average concentrations of Co, Ni and Cd at each station was DGT_1.92 > DGT_0.78 > DGT_0.39, suggesting stronger resupply from sediments to porewater when using thicker diffusive gels. Comparing centrifugation and DGT measurements, Co, Ni and Cd are highly labile; Mn and Fe are moderately labile; and Cu, Zn and Pb are slightly labile. The variations of AVS concentrations in sediment cores indicate that metal sulfides in deeper layers are easily diffused into surface sediments.