Effects of land use on concentrations of metals in surface soils and ecological risk around Guanting Reservoir,China

It is accepted that the historical routine use of agrochemicals may have resulted in undesirable concentrations of metals in the environment. To investigate and assess the effects of land use on concentrations of heavy metals around the Guanting Reservoir in China, 52 surface soil samples (depth of 2–10 cm) were taken from areas where four types of land use were practiced (including arable land, woodland, bare land, orchard land). The metals and metalloids (As, Cr, Ni, Cu, Zn, Cd, and Pb) were analyzed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Significant accumulation of As, Cd, and Cr was found in soils of arable land. Based on correlation and cluster analysis, it can be concluded that Cd and Zn originate mainly from phosphate fertilizer, Pb from the use of insecticides, fertilizers, and sewage sludge as well as air deposition, and Cu from copper-based fungicides, while As, Ni and Cr might come from parent soil material. According to an ecological risk analysis of metals based on the ecological index suggested by Hakanson, the four types of land can be ranked by severity of ecological risk as follows: arable land > woodland > bare land > orchard land, with a high ecological risk of Cd for all four types. Management measures for land use planners for avoiding water, soil, and sediment pollution caused by metals around the Guanting Reservoir are presented.     

电感耦合等离子体质谱法测定茶叶中的16种稀土元素

采用微波消解和干法灰化两种前处理方法,电感耦合等离子质谱(ICP-MS)测定了茶叶中的16种稀土元素.外标法绘制校准曲线,分析了国家标准物质茶叶GBW07605和GBW10016,测定值与标准值吻合,样品测定的精密度在0.6%-6.3 %,方法检出限为0.04-0.43 μg·kg-1.用加标回收的方法评价了该方法的准确性,回收率为96.0%-108.0%之间.     

长江水系沉积物中重金属的赋存形态

分析了长江干流和主要支流的沉积物样品中重金属(Cu,Zn,Pb,Cd,Cr,As,Hg)的含量和赋存形态.结果表明:除Zn外,长江流域水系沉积物中重金属的污染程度总体呈上升趋势,其中,Cd的污染较为严重,Cd主要以可交换态的形式存在,长江水系沉积物中Zn,Pb以及Cu具有相似的同源性,而Cd,As,Hg以及Cr则另为一类.     

水中紫外吸光度与COD的相关性

通过对地表水、生活污水和工业废水样品的紫外吸光度与化学需氧量（或高锰酸盐指数）测定值进行线性回归分析,得出不同类型水体的紫外吸光度与化学需氧量（或高锰酸盐指数）之间具有良好的相关性,在一定条件下,可利用测定的紫外吸光度推算出化学需氧量（或高锰酸盐指数）结果。     

水体中TOC与COD相关性研究

针对不同地区的地表水、生活污水和工业废水的TOC和COD进行了测试,对测定值进行线性回归分析。结果表明,不同类型的水体其TOC与COD均具有一定的相关性,尤其是生活污水和工业废水,TOC与COD相关性比较显著,在一定条件下可由测定的TOC值推算出COD值。     

2-(2-喹啉偶氮)-4-二乙氨基苯甲酸光度法测定镍的研究

合成了新试剂 2 -( 2 -喹啉偶氮 ) -4 -二乙氨基苯甲酸 ( QADEABA) ,并研究了其与镍的显色反应 ,在 p H=8.0的硼酸 -磷酸二氢钾缓冲介质中 ,吐温 -80存在下 ,QADEABA与镍反应生成 2∶ 1稳定络合物 ,λmax=5 90 nm ,ε=1 .1 8× 1 0 5L· mol-1· cm-1。镍含量在 0～ 0 .4 mg/ L内符合比耳定律 ,方法用于水样中镍含量的测定 ,结果令人满意     

室内外空气污染对学龄儿童呼吸系统影响的研究

通过对污染区和对照区 2 0 0 0多名学龄儿童呼吸系统症状、疾病患病率比较 ,并运用非条件 Logistic回归分析方法 ,就室内外空气污染对学龄儿童呼吸系统健康的影响 ,进行了研究。结果显示 ,污染区室内外空气污染较严重 ,大气中TSP、SO2 和 NOx 的浓度均超过国家二级标准 ,其儿童呼吸系统症状、疾病患病率明显高于对照区。对儿童呼吸系统发病有显著影响的环境因素是 :大气污染、被动吸烟、家庭燃煤、冬季取暖和室内油烟污染程度。其中咳嗽与以上五个因素有显著的正相关关系 (P<0 .0 5) ;除被动吸烟外 ,支气管炎与其它四个因素呈显著正相关 (P<0 .0 5) ;咳痰与大气污染、被动吸烟、冬季取暖和室内油烟污染程度 ,气喘和呼吸系统疾病住院率与大气污染和室内油烟污染正相关关系显著 (P<0 .0 5)。哮喘与室内外空气污染无显著的统计学联系     

Mechanisms of Pb(II) coprecipitation with natrojarosite and its behavior during acid dissolution

Lead (Pb) coprecipitation with jarosite is common in natural and engineered environments, such as acid mine drainage (AMD) sites and hydrometallurgical industry. Despite the high relevance for environmental impact, few studies have examined the exact interaction of Pb with jarosite and the dissolution behavior of each phase. In the present work, we demonstrate that Pb mainly interacts with jarosite in four modes, namely incorporation, occlusion, physically mixing, and chemically mixing. For comparison, the four modes of Pb-bearing natrojarosite were synthesized and characterized separately. Batch dissolution experiments were undertaken on these synthetic Pb-bearing natrojarosites under pH 2 to simulate the AMD environments. The introduction of Pb decreases the final Fe releasing efficiency of jarosite-type compounds from 18.18% to 3.45%-5.01%, showing a remarkable inhibition of their dissolution. For Pb releasing behavior, PbSO₄ dissolves in preference to Pb-substituted natrojarosite, i.e., (Na, Pb)-jarosite, which primarily results in the sharp increase of Pb releasing concentration (> 40 mg/L). PbSO₄ occlusion by jarosite-type compounds can significantly reduce the release of Pb. The results of this study could provide useful information regarding Fe and Pb cycling in acidic natural and engineered environments.     

改进式开顶气室模拟CO2浓度控制系统性能分析

为提高开顶气室（open-top chamber,OTC）模拟气候变化研究植物生理响应的控制效果,基于前期OTC控制系统基础,对气室结构、控制系统及监测系统改进升级。对改进后的OTC控制系统采集了试验期间5月—10月OTC气室内CO₂浓度、温度及空气相对湿度实时数据分析模拟效果,结果表明：改进后的OTC控制系统能够控制CO₂浓度达到试验预设浓度梯度,在试验期OTC气室内监测的CO₂浓度平均值对照组（CK）为369.33 μmol?mol^?1,处理1组（TR1）为558.35 μmol?mol^?1,处理2组（TR2）为772.71 μmol?mol^?1;CO₂浓度波动范围TR1组为551.82—572.40 μmol?mol^?1,变幅为20.58 μmol?mol^?1;TR2组为756.71—779.79 μmol?mol^?1,变幅为23.08 μmol?mol^?1,满足试验预设模拟要求;气室内不同处理间温度、空气相对湿度差异均不显著（p＞0.05）。改进后的OTC控制系统模拟效果好,可用于研究植物响应气候变化的模拟试验。     

Effects of tetrakis (hydroxymethyl) phosphonium sulfate pretreatment on characteristics of sewage sludge

Recently, tetrakis(hydroxymethyl)phosphonium sulfate(THPS) was found to play an important role in the sludge pretreatment process. However, the effects of THPS pretreatment on the characteristics of sewage sludge are still insufficiently understood.The properties of sludge after pretreatment with different concentrations of THPS were investigated in this study. The results showed that pH, dewatering ability, and particle size of sludge decreased with increase in THPS concentration. The volatile suspended solids(VSS) and total suspended solids(TSS) of sludge also decreased slightly with increase in THPS concentration. The specific oxygen uptake rate(SOUR) results suggested that lower THPS concentrations(≤ 1.87 mg/g VSS) enhanced the activity of sludge, but higher concentrations(≥ 1.87 mg/g VSS) inhibited it. Gram-negative bacteria with peritrichous flagellation(such as Pseudomonas, Escherichia, and Faecalibacterium) were extremely sensitive to THPS. The decrease in specific most probable numbers(MPNs) of pathogens(total coliforms and Escherichia coli) with the increase in THPS concentration also proved the sterilization ability of THPS in the sludge pretreatment process. Pretreatment of sludge with concentrations of THPS higher than 37.41 mg/g VSS would meet the pathogen requirements for land application of Class A biosolids.