天津近海夏季大气颗粒物元素特征及来源解析

2006年夏季在天津近海海域走航采集总悬浮颗粒物(TSP)样品,用于研究近海海域大气颗粒物污染特征和来源。采集到的样品通过重量分析得到颗粒物浓度,同时进行元素分析。并结合气象要素分析,显示陆源污染物在陆风影响下传输到海上,解释了采样期间近海海域TSP浓度较高的现象。研究使用富集因子和化学质量受体平衡(CMB)模型对近海海域TSP进行解析。通过富集因子分析,估计近海海域TSP来源主要有人为源、地壳源和海盐粒子源。CMB结果显示燃煤飞灰所代表的人为源对TSP贡献最大(36.14%),其次是地壳源类(33.26%)以及海盐粒子(1.58%),其他未识别的源为30.58%。由此推断陆地污染源对近海海域大气颗粒物的贡献远远高于海盐粒子,因此对渤海周围陆地污染源的控制应得到足够重视。     

洪湖流域半封闭池塘河蟹养殖氮磷污染负荷研究

选取洪湖流域半封闭池塘河蟹养殖区域为调查样本,针对一个养殖周期内6个监测点位(1个背景点,3个养殖水体点,2个纳污水体点)TN、TP值进行监测分析。监测结果表明,养殖准备期(12月～1月),养殖水体TN、TP值与同期背景值没有明显差异;养殖中后期(3月～10月),养殖水体和纳污水体TN、TP均明显高于同期背景值,大部分为劣Ⅴ类水质。按5～10月份养殖水体TN、TP实测值进行化学分析法估算,一个养殖周期内养殖水体TN、TP污染负荷为27.61kg/hm2、7.33kg/hm2,则洪湖流域半封闭池塘河蟹养殖排放的TN、TP污染负荷约为269.11t/a、71.46t/a。另据对样本区域养殖生产过程的调查,按物料平衡法估算的TN、TP污染负荷为57.61kg/hm2、11.60kg/hm2,而洪湖流域半封闭池塘河蟹养殖TN、TP污染负荷约为561.51t/a、113.06t/a。     

Zn~(2+)-S~(2-)-H_2O系热力学平衡研究

根据配位化学热力学平衡原理,绘制了温度为298.15K时Zn2+-S2--H2O系pC-pH热力学平衡状态图。结果表明:ZnS溶解平衡时,随着pH值的增加,ZnS的溶解度先减少后增加,当pH值为8.36时,ZnS的溶解度最小,为10-7.69mol/L;Zn(OH)2溶解平衡时,随着pH值的增加,Zn(OH)2的溶解度也呈现先减少后增加,当pH值在9.41时Zn(OH)2的溶解度最小,为10-5.61mol/L;体系中ZnS和Zn(OH)2二者固相溶解平衡时,当S2-Zn2(+mol)时,pH在0～14范围内只生成ZnS沉淀,不会产生Zn(OH)(2s)物质。研究结果可为硫化沉淀法去除废水中锌等技术提供理论依据。     

广州某商业中心雨水回收利用设计

以某商业中心为例,介绍了屋面雨水回收用于空调冷却塔补水的设计。根据广州地区雨水资源丰富、水质良好及工程项目的特点,确定了雨水回收范围、回收用途,并进行了月均水量平衡计算。经济效益分析表明,该系统每年可节约市政供水34000m^3,经济效益和环境效益显著。     

三叶鬼针草幼苗对镉污染的耐性及其吸收积累特征研究

通过盆栽实验研究了镉(Cd)胁迫下三叶鬼针草(Bidens pilosaL.)幼苗的耐性能力(包括生长反应和生理生化特性)以及对Cd的吸收积累特征.结果表明,当土壤中投加的Cd浓度为≤32 mg/kg时,三叶鬼针草植物的生长和发育没有受到抑制,与对照相比,地上部和根部生物量分别增加了32.4%~44%和29.1%~57.6%,其中,当Cd处理浓度为8 mg/kg时,地上部干重达到最大值,为0.22 g/pot.在不同Cd处理下,叶绿素(Chl)和可溶性蛋白(SP)含量下降,分别比对照处理降低了23.3%和41.5%;超氧化物歧化酶(SOD)活性随着Cd浓度增加先有所抑制,后逐渐增大;过氧化物酶(POD)活性和丙二醛(MDA)含量随Cd处理浓度增加而增大,分别比对照增加了1.2~6.6和1.1~1.5倍.然而,当Cd浓度为50~100 mg/kg时,显示出对三叶鬼针草幼苗的生长发育和生理生化特征都产生了一定的负效应,说明三叶鬼针草对Cd污染的耐性能力具有一定的阈值.在梯度实验中,植物体内Cd的富集系数和转移系数都大于1.0.当土壤中Cd含量达到100 mg/kg时,地上部Cd含量达到119.1 mg/kg,具备...     

垃圾焚烧中吸附剂对Cd、Pb迁移分布的影响

利用管式炉和模拟垃圾,研究了焚烧过程中SiO₂、Al₂O₃、CaO等吸附剂对重金属Cd、Pb迁移分布的影响规律,考察了不同吸附剂添加量、管式炉反应温度和停留时间的影响.结果表明,在各反应温度下,SiO₂、Al₂O₃、CaO均有利于Cd停留在底渣中;对于Pb,SiO₂、Al₂O₃亦使其易于停留在底渣中,而CaO在高温时表现为使Pb更易于向飞灰迁移.上述影响的程度均随着吸附剂添加量的增加而增加.当反应炉温度为850℃时,各吸附剂对于Cd的吸附效果顺序为CaO>Al₂O₃>SiO₂,对Pb的顺序为Al₂O₃>SiO₂>CaO.反应炉温度和停留时间的增加,也都易于使Cd、Pb向飞灰迁移.     

Pb（II） biosorption using chitosan and chitosan derivatives beads： Equilibrium, ion exchange and mechanism studies

The study examined the adsorption of Pb(II) ions from aqueous solution onto chitosan, chitosan-GLA and chitosan-alginate beads. Several important parameters influencing the adsorption of Pb(II) ions such as initial pH, adsorbent dosage and di erent initial concentration of Pb(II) ions were evaluated. The mechanism involved during the adsorption process was explored based on ion exchange study and using spectroscopic techniques. The adsorption capacities obtained based on non–linear Langmuir isotherm for chitosan, chitosan-GLA and chitosan-alginate beads in single metal system were 34.98, 14.24 and 60.27 mg/g, respectively. However, the adsorption capacity of Pb(II) ions were reduced in the binary metal system due to the competitive adsorption between Pb(II) and Cu(II) ions. Based on the ion exchange study, the release of Ca2+, Mg2+, K+ and Na+ ions played an important role in the adsorption of Pb(II) ions by all three adsorbents but only at lower concentrations of Pb(II) ions. Infrared spectra showed that the binding between Pb(II) ions and the adsorbents involved mostly the nitrogen and oxygen atoms. All three adsorbents showed satisfactory adsorption capacities and can be considered as an e cient adsorbent for the removal of Pb(II) ions from aqueous solutions.     

我国淡水水生生物镉基准研究

研究了Cd对我国淡水水生生物的毒性效应,包括43种生物的急性毒性数据和14种生物的慢性毒性数据.同时,参照美国环境保护署（USEPA）颁布的水质基准计算方法,按照基准最大浓度（CMC）和基准连续浓度（CCC）计算了我国淡水水生生物的Cd基准.结果表明,我国淡水生物Cd基准的CMC值和CCC值分别为2.1 μg·L-1和0.23 μg·L-1,与美国淡水生物Cd的基准值有一定差别,研究结果为我国的Cd水质标准研究提供了参考依据.     

Secondary organic carbon quantification and source apportionment of PM10 in Kaifeng, China

During 2005, the filter samples of ambient PM₁₀ from five sites and the source samples of particulate matter were collected in Kaifeng, Henan Province of China. Nineteen elements, water-soluble ions, total carbon (TC) and organic carbon (OC) contained in samples were analyzed. Seven contributive source types were identified and their contributions to ambient PM₁₀ were estimated by chemical mass balance (CMB) receptor model. Weak associations between the concentrations of organic carbon and element carbon (EC) were observed during the sampling periods, indicating that there was secondary organic aerosol pollution in the urban atmosphere. An indirect method of “OC/EC minimum ratio” was applied to estimate the concentration of secondary organic carbon (SOC). The results showed that SOC contributed 26.2%, 32.4% and 18.0% of TC in spring, summer-fall and winter, respectively, and the annual average SOC concentration was 7.07 μg/m³, accounting for 5.73% of the total mass in ambient PM₁₀. The carbon species concentrations in ambient PM₁₀ were recalculated by subtracting SOC concentrations from measured concentrations of TC and OC to increase the compatibility of source and receptor measurements for CMB model.     

Joint effects of cadmium and lead on seedlings of four Chinese cabbage cultivars in northeastern China

In northeastern China, large area of vegetable land has been simultaneously polluted by cadmium (Cd) and lead (Pb). Joint e ects of Cd and Pb on Chinese cabbage (Brassica pekinensis L.) were investigated using the seed germination and sand culture method. Four Chinese cabbage cultivars including Kangbingjinchun (KB), Dongyangchunxia (DY), Qinglvwang (QL) and Qiangshi (QS) from Shenyang in northeastern China were adopted in this study. The results showed that there were positive linear relationships between the inhibitory rate of biomass, root and shoot elongation and the concentrations of Cd and Pb. In particular, root elongation was more sensitive to joint stress of Cd and Pb. The activity of superoxide dismutase and the content of malondialdehyde (MDA), soluble protein (SP) and proline (PRO) changed significantly with increasing exposure concentration of Cd and Pb. The decrement in the activity of antioxidative enzymes, the content of SP and accumulation of MDA were relatively low in KB and QS. PRO played an important role in resisting Cd and Pb stress.