三峡水库135 m蓄水前后水体重金属环境健康风险评价

三峡水库135 m蓄水后,水体中各重金属的单因子污染指数和Nemerow综合污染指数均有不同程度的增大,特别是Pb污染应该引起重视.健康风险评价结果表明,成库前后非致癌有毒化学物质(Hg、Pb和Cu)所引起的健康危害的个人年风险为Pb＞Cu＞Hg,致癌物质对人体健康危害的个人年风险均大于非致癌物.各类污染物所致个人平均健康危害成库前后均低于国际辐射防护委员会(ICRP)推荐的标准,为可接受水平.     

水葱修复土壤镉污染潜力的研究

野外观察与研究发现水葱(Scirpus tabernaemontani G.)可以耐受土壤中高浓度的重金属污染,并对镉(Cd)有很高的生物富集量.实验室水培试验研究了两个主要因素,营养液pH与Cd含量,对水葱生物量以及Cd富集效果的影响.结果表明,它可耐受高浓度Cd (30 mg/L)和大范围pH变化 (3.7～7.7).当营养液pH为4.7, Cd为25 mg/L时,水葱富集的Cd达到最大值:地上部分264.71 mg/kg,地下部分234.39 mg/kg,平均转运系数1.13.这显示了它用于植物修复Cd污染土壤的潜力.     

饮用水生物处理中微生物量和活性的测定方法

微生物量和微生物活性是饮用水生物处理工艺设计与运行的重要参数。总结论述了适用于表示饮用水生物处理过程生物膜中微生物数量和活性的几种主要指标的测定方法。     

公路地表灰尘及径流中颗粒物附着重金属对比研究

对北京城区北三环上北太平桥以西约300 m处路段地表灰尘及径流中不同粒径颗粒物附着重金属载荷进行对比研究.结果表明:(1)随着颗粒物粒径的增大,地表灰尘中颗粒物附着重金属浓度总体上逐渐降低;地表灰尘中<40.00 μm颗粒物附着重金属浓度最高;重金属载荷分布集中度不强,但主要集中在地表灰尘中<300.00 μm的颗粒物L.(2)地表径流中大部分重金属附着在<125.00 μm颗粒物上;0.45～10.00 μm颗粒物附着重金属载荷最高;0.45～40.00 μm颗粒物附着重金属载荷平均为77.1%.(3)地表灰尘中<40.00 μm的颗粒物的潜在水环境风险不太突出,但是其实际水环境影响却起主导作用.(4)进入水体的小粒径颗粒物质量分数升高是地表灰尘和径流重金届载荷随颗粒物粒径分布不同的重要原因之一;大气湿沉降对小粒径颗粒物重金属载荷可能会有一定的影响.     

Ag~+改性复合钛铌酸钾盐对二甲基硫醚和乙硫醇吸附与光催化氧化研究

采用高温固相法合成具有不同Nb/Ti摩尔比的复合钛铌酸钾盐,通过Ag+离子交换对其进行改性。在静态下评价了Ag+改性复合钛铌酸钾盐对二甲基硫醚(DMS)和乙硫醇(EM)的吸附与紫外光催化氧化作用,使用红外光谱技术对催化剂表面滞留物种进行表征。结果表明,Ag+改性复合钛铌酸钾盐对DMS的吸附作用力比EM弱。随着Nb/Ti摩尔比增加,Ag+改性复合钛铌酸钾盐对EM的吸附作用力增强。在紫外光辐射下,Ag+改性的复合钛铌酸钾盐将DMS氧化为亚砜、砜和硫酸盐,而EM则被氧化为磺酸和单齿硫酸盐。     

Potentially toxic metal contamination of urban soils and roadside dust in Shanghai, China

A detailed investigation was conducted to understand the contamination characteristics of a selected set of potentially toxic metals in Shanghai. The amount of Pb, Zn, Cu, Cr, Cd and Ni were determined from 273 soil/dust samples collected within urban area. The results indicated that concentration of all metals except Ni in soils was significant, and metal pollution was even severer in roadside dust. A series of metal spatial distribution maps were created through geostatistical analysis, and the pollution hotspots tended to associate with city core area, major road junctions, and the regions close to industrial zones. In attempt of identifying the source of metals through geostatistical and multivariate statistical analyses, it was concluded as follows: Pb, Zn and Cu mainly originated from traffic contaminants; soil Ni was associated with natural concentration; Cd largely came from point-sourced industrial pollution; and Cr, Ni in dust were mainly related to atmospheric deposition.     

竹炭-微生物联合法对沼液中氨氮的去除

采用竹炭-微生物联合法,考察了竹炭用量、菌液用量、进水氨氮浓度、pH、DO、HRT等因素对氨氮废水处理效果的影响;同时采用对比实验,初步探讨了竹炭-微生物联合法处理沼液的作用机理。结果表明,竹炭-微生物法去除沼液氨氮的最优条件推荐为:竹炭用量30 g/L,微生物活性液用量3%,pH 7.0～8.0,DO为2 mg/L,HRT为48 h。竹炭-微生物法对沼液氨氮的去除过程可用一级反应动力学模型C=272.56e-0.0148描述,其去除效果来源于竹炭吸附和生物降解的协同作用,协同程度为48.45%。     

Perfluorooctane sulfonate (PFOS) and other fluorochemicals in fish blood collected near the outfall of wastewater treatment plant (WWTP) in Beijing

Perfluorinated compounds (PFCs) were measured in zooplankton and five fish species collected from Gaobeidian Lake, which receives discharge from wastewater treatment plant (WWTP) in Beijing, China. The mean total PFCs in five fish were in the order: crucian carp > common carp > leather catfish > white semiknife carp > tilapia. Perfluorooctane sulfonate (PFOS) occurred at the greatest concentrations, with mean concentrations ranging from 5.74 to 64.2 ng/ml serum. Perfluorodecanoic acid (PFDA) was the second dominant PFC in fish samples except for common carp in which perfluorooctane sulfonamide (PFOSA) was dominant. A positive linear relationship (r² = 0.85, p < 0.05) was observed between ln PFOS concentrations (ln ng/ml) and trophic level (based on δ¹⁵N) if tilapia was excluded. The risk assessment showed that PFOS might not pose an immediate risk to fish in Gaobeidian Lake.     

不同曝气方式下SBR亚硝化的实现及NO2--N积累效果

研究不同曝气方式下亚硝化的实现以及基质浓度、曝气频率和温度对NO-2-N积累效果的影响。以实际污泥脱水液为研究对象,控制进水NH+4-N浓度在50~80 mg/L范围内,温度为27℃,pH值为7.8~8.2,DO浓度为0.5~1.0mg/L,分别采用连续曝气和间歇曝气2种方式启动SBR亚硝化反应器,并考察了在不同基质浓度、曝气频率和温度条件下NO-2-N累积情况。实验研究结果表明,经过40 d左右的运行,在2种不同曝气方式下SBR均成功实现了亚硝化,稳定运行阶段,NO-2-N积累率分别达到95%和85%。经SEM扫描电镜观察发现,在驯化成熟的活性污泥中,亚硝化细菌多呈球状和杆状,大小不同,外形饱满。当进水氨氮浓度小于200 mg/L,曝气频率为曝气15 min/停曝15 min,温度为27℃时,NO-2-N积累效果最佳,平均积累率可达90%以上。间歇曝气可以有效促进亚硝化细菌富集,有利于实现较高浓度的NO-2-N积累。基质浓度、曝气频率和温度对NO-2-N积累效果的影响显著。     

Estimation and characterization of unintentionally produced persistent organic pollutant emission from converter steelmaking processes

Unintentionally produced persistent organic pollutants (UP-POPs) including polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were characterized and quantified in stack gas and fly ash from the second ventilation systems in five typical converters in five different steelmaking plants. The 2378-substituted PCDD/Fs (2378-PCDD/Fs) and dioxin-like PCB (dl-PCBs) toxic equivalents (TEQs) were 1.84–10.3 pg WHO-TEQ Nm^?3 in the stack gas and 5.59–87.6 pg WHO-TEQ g^?1 in the fly ash, and the PCN TEQs were 0.06–0.56 pg TEQ Nm^?3 in the stack gas and 0.03–0.08 pg TEQ g^?1 in the fly ash. The concentrations of UP-POPs in the present study were generally lower than those in other metallurgical processes, such as electric arc furnaces, iron ore sintering, and secondary metallurgical processes. Adding scrap metal might increase UP-POP emissions, indicating that raw material composition was a key influence on emissions. HxCDF, HpCDF, OCDF, HpCDD, and OCDD were the dominant PCDD/Fs in the stack gas and fly ash. TeCB and PeCB were dominant in the stack gas, but HxCB provided more to the total PCB concentrations in the fly ash. The lower chlorinated PCNs were dominant in all of the samples. The 2378-PCDD/F, dl-PCB, and PCN emission factors in stack gases from the steelmaking converter processes (per ton of steel produced) were 1.88–2.89, 0.14–0.76_, and 229–759 μg t^?1, respectively.