Toxicity evaluation of sewage sludges in Hong Kong.

Anaerobically digested sewage sludges collected from four wastewater treatment plants located in Sha Tin, Tai Po, Yuen Long, and Shek Wu Hui in Hong Kong were subjected to chemical characterization and toxicity testing to provide preliminary assessment of their suitability for land application. All sewage sludges were slightly alkaline with pH range of 8.3-8.7. Electrical conductivity (EC; 0.69 dS m(-1)) and soluble NH4-N content (996 mg kg(-1)) of sewage sludge from Yuen Long were lower than that of other plants. Concentrations of heavy metals were determined as total, extractable, and water-soluble fraction using mixed acid digestion, DTPA (pH 7.3), and distilled water, respectively. Yuen Long sludge was most polluted with Zn and Cr higher than the pollutant concentration limits listed in Part 503 of USEPA, owing to the effluent coming from the tannery industry. High concentration of Ni was found in sludge from Sha Tin that originated mainly from the electroplating industry. DTPA-extractable Zn contents were high in sludges from Yuen Long (1247 mg kg(-1)) and Shek Wu Hui (892 mg kg(-1)), while 3.7 mg kg(-1) of DTPA-extractable Cr was found in Yuen Long sludge. Metal speciation of sludges showed that Pb was major in residual phase while Cu, Cr, and Ni in organic and residual phases, and Zn did not show any dominant chemical phase. The sludge extracts did not exert significant adverse effect on seed germination of Brassica chinensis (Chinese cabbage), but Yuen Long sludge caused a reduction in root growth. In view of its lower EC and soluble ammonia contents, the high concentration of Zn and Cr in Yuen Long sludge would likely be responsible for this adverse effect on root growth. Therefore, Yuen Long sludge would likely have a more serious impact on soil quality and plant growth as compared to other sludges. This would require further verification from greenhouse and field experiments.     

Ecosystem management based on ecosystem services and human activities: a case study in the Yanhe watershed

With activities that alter the structure and function of the habitat, humans have a direct impact on ecosystems and ecosystem services, i.e., the conditions and processes that sustain human life. In this study, 35 townships in the Yanhe watershed in the Loess Plateau of China were selected. The net primary production (NPP), carbon sequestration and oxygen production (CSOP), water conservation, and soil conservation were the ecosystem services selected and valuated. Human activity was quantified by an integrated human activity index (HAI) based on population density, farmland ratio, and the influence of road networks and residential areas. The NPP, CSOP, and water conservation showed a conspicuous spatial pattern fanning outward from the southwest, while the soil conservation showed an obscure spatial pattern distinguished primarily by the peripheral area surrounding the urbanized areas. Total ecosystem services in the Yanhe watershed demonstrated a decreasing pattern from south to north, and the HAI was in proportion to administrative and economic development. Based on the selected ecosystem services and HAI, we mapped the townships of the Yanhe watershed by cluster analysis, and provided sustainable ecosystem management suggestions, tailored to the social-ecological map.     

安徽省霾时空分布特征分析

利用安徽省78个气象台站1971～2010年能见度和相对湿度资料,统计出历年各站霾发生日数并分析其时空分布特征,通过历年霾日数变化趋势、EOF分析等方法对安徽省近40 a霾的气候变化特征进行分析。结果表明：安徽省霾日数存在显著的增多趋势;霾高发期在秋冬季,1月更是一年中霾发生最多的月份;5～6月是霾发生的次高峰,6月的极重霾为全年中最多;白天出现霾的几率高于夜晚,早上8时是一天中最容易出现霾的时刻。安徽省霾年平均日数的空间分布很不均匀,平原多于山区,主要城市及周边地区的年平均霾日数较多,山区很少;沿淮淮北的极重霾日数最多。2007年前后霾的年平均日数达到40 a来的最高值。霾日数EOF前4个模态累积方差贡献为793％,说明安徽省绝大部分地区霾日数随年代的变化都是呈增长趋势;时间系数表现为明显的年代变化,以3～4 a周期震荡增长为主     

Population dynamics of the barnacle <Emphasis Type="Italic">Chthamalus montagui</Emphasis> at two spatial and temporal scales in northern Spain

This study describes spatial and temporal patterns of variability in population parameters in the barnacle Chthamalus montagui Southward in three localities of northern Spain and evaluates whether density-dependent settlement may regulate population dynamics. The sampling design considered two spatial scales, localities and sites within localities, and two temporal scales, years and six month intervals. Density, amount of free space, mortality, growth rate and magnitude of settlement (both absolute and per unit of free space) were obtained from photographs of permanent quadrats and from direct counts in the field. The number of settlers in scraped and untouched quadrats was used to estimate the importance of the presence of conspecifics in settlement. Significant variation at the two spatial and temporal scales was found for most parameters. Large spatial and temporal variations in adult mortality rate, density, and settlement were observed. Patterns of mortality were not consistent with differences in density among localities. Differences in settlement among localities were maintained through time. We suggest that magnitude of settlement is regulated by persistent features such as topography or local water circulation. We assume that early post-settlement mortality does not differ among localities. In the absence of differential mortality, settlement determines average population density within localities. Within localities, settlement was independent of density and free space. No consistent evidence was found on preferential settlement at the vicinity of conspecifics. The main conclusion is that density-dependent settlement is not relevant for the regulation of the populations of C. montagui in the northern Spain. Regulation might occur by density-dependent processes within the adult fraction of the population and/or the larval phase before settlement.     

藻红外辐射测试环境重金属急性毒性

快速、简便、有效地检测环境中重金属毒性是环境保护的一项重要内容.敏感藻是指藻红外测试中对毒物响应的温差大、种类多、时间快、剂量低的特殊藻类,为探寻对重金属急性毒性响应的敏感藻,2006年5月至2007年10月,进行了8种藻对10种重金属的温度响应测试试验.结果表明:平均响应温差短线脆杆藻(Fragilaria brevistriata)最大,为0.24 ℃,高出8种藻的0.19 ℃总平均温差0.05 ℃;较好药品响应率短线脆杆藻最高,为80%;平均响应时间短线脆杆藻居中,为4.65 min,低于8种藻的总平均响应时间5.21 min;短线脆杆藻对重金属的灵敏度在0.06～7.0 mg?L-1之间,发光细菌在0.07~15.3 mg?L-1之间,表明短线脆杆藻对重金属响应的剂量低.根据敏感藻的定义和分析结果,确定短线脆杆藻为本试验的敏感藻.     

硫酸盐还原菌和酸性矿山废水的生物处理

本文论述了硫酸盐还原菌的代谢和所需要的碳源以及硫酸盐还原的影响因素和生物处理酸性矿山废水的研究进展.     

不同补给水源的城市人工湖中异养菌耐药性及耐药菌种属分布研究

为了阐明不同补给水源的城市人工湖中异养菌耐药状况和耐药菌种属分布特征,选取分别以地表水和再生水为补水来源的XQ湖和FQ湖为代表进行研究。从2018年4—11月逐月采集水样,考察了各水样中对氨苄西林(AMP)、磺胺甲恶唑(SMZ)和四环素(TET)这3种不同种类抗生素具有耐药性的异养菌含量,并对分离菌株的耐药表型、耐药菌株的种属分布以及水质理化指标进行了分析。结果表明,2处人工湖中的AMP耐药菌和SMZ耐药菌含量约为10~2～10~4CFU·(100 m L)~(-1),而TET耐药菌含量则约10~1～10~3CFU·(100 m L)~(-1)。分离出的84株耐药菌归属于19个种,其中蜡状芽孢杆菌、大肠埃希氏菌、维氏气单胞菌、豚鼠气单胞菌和鸟氨酸拉乌尔菌为2个湖共有耐药菌。71.4%的耐药菌都是对AMP单一耐药,以蜡状芽孢杆菌为主。由于具有固有耐药性的细菌在分离出的耐药菌中占比很低,获得性耐药很可能在城市人工湖中异养菌耐药性的发展上发挥了主要贡献作用。地表水补水的XQ湖和再生水补水的FQ湖在总异养菌含量、耐药菌含量和检出率上均无显著差异。分离来源对16株耐药性气单胞菌的聚类无明显影响。     

某大型化工企业周边居民区积尘中多环芳烃调查及健康风险评价

以江苏省某大型化工企业周边居民区为研究区域,调查企业主导风的下风向2 km范围内的居民区以及对照区积尘中多环芳烃(PAHs)含量,对16种PAHs污染分布和特征进行研究,并评估积尘PAHs通过暴露途径对人群健康风险。结果表明:居民区积尘中16种PAHs全部检出,污染区∑PAHs均值为2 294μg/kg,明显高于对照区145μg/kg;污染区7个测点中有6个测点苯并(a)芘出现超标,超标倍数为0. 17～2. 5倍;所测的16种PAHs化合物中蒽、荧蒽、芘、、苯并(b)荧蒽、苯并(k)荧蒽、苯并(a)芘浓度相对较高;通过PAHs主成分分析和特征比值判断,不完全燃烧源对积尘中PAHs贡献率达77. 4%,污染区PAHs来源呈现石油燃烧、煤燃烧以及石油源的复合污染特征,对照区PAHs主要来源为煤的不完全燃烧;以苯并(a)芘毒性等效浓度进行风险评估,污染区致癌风险值明显高于对照区,儿童摄入PAHs风险总体高于成人;对照区儿童和成人致癌风险均小于1×10~(-6),不存在致癌风险;污染区儿童和成人平均致癌风险值分别为3. 95×10~(-6)、2. 65×10~(-6),在可接受范围内,但存在潜在致癌风险。     

高炉瓦斯泥对Cu(Ⅱ)的吸附

采用等离子体发射光谱、N2吸附和傅里叶红外光谱技术(FT-IR)对高炉瓦斯泥(BFS)进行了表征,测得其BET比表面积为21.13 m2/g、并且含有羟基、酯基等功能性官能团。实验考察了吸附剂用量、pH值、吸附温度、Cu(Ⅱ)初始浓度对高炉瓦斯泥吸附Cu(Ⅱ)的影响,结果表明,当Cu(Ⅱ)初始浓度为100 mg/L时,温度为313 K、高炉瓦斯泥用量为1.5g/L、pH=5时,20 min可达到吸附平衡,吸附率为99.99%。并且吸附过程符合准二级动力学反应模型以及Freundlich吸附等温式,其表观活化能Ea=58.27 kJ/mol,该吸附过程是自发的、吸热的熵增过程。     

孔口分布及空气流速对充氧性能的影响

实验采用鼓风曝气,改变曝气量,研究孔口分布及空气流速对清水充氧性能的影响。通过考察氧总转移系数KLa(20)、充氧能力N0和氧转移效率E3项指标,得出该曝气设备的最佳运行条件:在曝气量为9 m3/h时,选用曝气器B进行曝气。这样可以得到较高的KLa(20)(1.816 h-1)、N0(0.105 kg/h)和E(4.151%),为曝气设备的实际应用提供参考。