医院和实验室室内环境中挥发性有机污染物的比较

分别采集了医院和实验室环境空气样品,通过GC-MS/FID对样品进行定性分析.共定性检测出116种挥发性有机物(VOCs).在这两类环境中检出频次较高的VOCs物种包括乙烷、丙烷、正丁烷等烷烃;乙烯、丙烯、1-丁烯等烯烃;苯、甲苯、乙苯等芳香烃;氯甲烷、二氯甲烷等卤代烃和丙酮等含氧有机物.在实验室中经常使用的试剂如正己烷、甲苯、乙醇、丙酮等呈现较高的水平,高于室外1~3个数量级.在医院的部分候诊区中检出较高浓度的甲苯、乙苯、二甲苯,需要引起关注.     

电辅助对厌氧折流板反应器处理高浓度有机废水的影响

为探究电辅助对ABR(厌氧折流板反应器)处理高浓度有机废水效能的影响,在温度为(35±1)℃、HRT(水力停留时间)为24 h、进水ρ(COD_Cr)维持在5 000 mg/L的情况下,研究电辅助位置对COD_Cr去除率、各格室VFA(挥发性脂肪酸)质量浓度和组成以及微生物群落的影响. 结果表明:①电辅助作用于反应器第1格室时,COD_Cr去除率达最大值(83.19%),较对照组提高约15.23%;1#-1格室ρ(乙酸)提高约23.26%,而ρ(丙酸)下降78.09%,说明电辅助能有效提高产氢产乙酸菌丙酸转化乙酸能力,有利于反应器性能提高. ②当电辅助添加在第2格室时,2#-2格室ρ(乙酸)略有下降,而ρ(丙酸)提高近4.2倍,电辅助对水解发酵菌促进效果明显,作用格室表现为乙酸-丙酸发酵类型. ③电辅助ABR各格室微生物群落结构的相似度均在70.0%以下,表明电辅助在强化不同优势菌群的同时改变了微生物种群结构.      

用苎麻生物脱胶废水生产热带假丝酵母单细胞蛋白

采用热带假丝酵母处理苎麻生物脱胶废水。将COD为23 060 mg/L的苎麻生物脱胶废水稀释1倍后进行发酵处理,COD去除率最高,为60.85%。发酵条件的正交实验结果表明:在发酵温度为35℃、初始发酵pH为7.0、接种量为10%、发酵时间为48 h的条件下,苎麻生物脱胶废水COD去除率最高;发酵温度为30℃、初始发酵pH为7.0、接种量为10%、发酵时间为48 h的条件下,单细胞蛋白生成量最高。发酵时间为48 h时,灭菌的发酵培养基的COD去除率为75.75%,单细胞蛋白生成量为5.375 g/L;未灭菌的发酵培养基的COD去除率为72.25%,单细胞蛋白生成量为2.875 g/L。     

BAF处理焦化尾水和钢厂杂排水的研究

结合4万m3/d污水处理及回用工程的调试实践,对采用曝气生物滤池技术处理焦化尾水和钢厂杂排水的处理效果进行研究。结果表明:曝气生物滤池有一定的抗有机负荷冲击能力;对SS的去除效果好;进水有机负荷的大小是影响氨氮去除效果的一个重要因素;B/C是曝气生物滤池降解有机物效果好坏的重要因素。根据调试中实际操作情况确定:水反冲洗强度为5.83 L/(m2.s);气反冲洗强度为16 L/(m2.s);反冲洗周期为5 d,各反冲阶段时间分配:气洗时间为5 min,气水联合洗时间为3 min,水漂洗时间为5 min,反洗后,大约6 h出水恢复到反洗前的处理效果。     

壳聚糖稳定纳米铁去除地表水中Cr(Ⅵ)污染的影响因素

以壳聚糖为稳定剂,制备纳米零价铁颗粒,TEM表征结果显示:其粒径分布范围为20—150 nm,平均粒径为82.4 nm.研究表明,壳聚糖稳定的纳米铁去除Cr(Ⅵ)的还原反应符合一级反应动力学方程.溶液中投加稳定剂壳聚糖,当壳聚糖浓度为150 mg.l-1时,80 min内表观一级动力学常数kobs约为空白溶液的2倍;干扰离子Ca2+,Mg2+,HCO3-和CO32-对壳聚糖稳定纳米铁去除Cr(Ⅵ)的批试验结果显示,Ca2+和Mg2+在80 min内使壳聚糖稳定纳米铁对Cr(Ⅵ)去除率分别降低了约20%和10%;HCO3-和CO32-的存在使去除率降低了约10%.     

Vocal competition in male Xenopus laevis frogs

Male Xenopus laevis frogs produce underwater advertisement calls that attract gravid females and suppress calling by male competitors. Here we explore whether groups of males establish vocal ranks and whether auditory cues alone suffice for vocal suppression. Tests of male–male pairs within assigned groups reveal linear vocal dominance relations, in which each male has a defined rank. Both the duration over which males interact, as well as the number of competitive opportunities, affect linearity. Linear dominance across the group is stable for about 2 weeks; rank is dynamic. Males engage in physical interactions (clasping) while paired but clasping and vocal rank are not correlated. Playbacks of advertisement calls suppress calling and calls from high- and low-ranking males are equally effective. Thus, auditory cues alone suffice to suppress vocal behavior. Playback intensities equivalent to a nearby male advertising effectively suppress calling while low-intensity playbacks are either ineffective or stimulate vocal behavior. X. laevis advertisement calls are biphasic, composed of alternating fast and slow click trills. Approximately half the males tested are more vocally suppressed by all slow than by all fast trills; thus, these males can distinguish between the two phases. The fully aquatic family Pipidae diverged from terrestrial ancestors approximately 170 mya. Vocal suppression in the X. laevis mating system may represent the translation of an ancient anuran social strategy to underwater life.     

Predicted effects of climate change,vegetation and tree cover on dune slack habitats at Ainsdale on the Sefton Coast,UK

Dune slack habitats are highly dependent on the availability of water to support flora and fauna. Typically this is provided by shallow groundwater. This paper describes the seasonal and long term variation in groundwater levels in part of the Sefton coastline between 1972 and 2007. The effects of climate change, vegetation management and coastline realignment on groundwater levels are modelled. The observed annual water table levels rise and fall with an amplitude of 1.5 m, but longer term variations and trends are apparent. A stochastic water balance model was used to describe the changes in water table levels in slack floors in the open dunes and also in areas afforested with pine trees. It was found that the pine trees evaporated 214 mm/year more than open dunes vegetation, resulting in the water table being 0.5–1.0 m lower under the trees than under the open dunes. The effects of climate change on the ground water was simulated using predictions of future climate conditions based on the UKCIP02 medium high emissions scenario. The increase in temperature and change in rainfall patterns will result in a decrease in mean ground water levels by 1.0–1.5 mm in the next 90 years. Typical patterns consist of sequences of 5–10 years of low water table levels interspersed by infrequent sequences consisting of 2–5 years of relatively high or “normal” levels. These results indicate that that flora and fauna that cannot survive a 5–10 year period of water table levels >2.5 m below ground level are unlikely to survive or persist in many slack areas and a change in the ecology of these slack may become inevitable. Other effects of climate change include sea level rise which will result in a gradual rise in water table levels. Coastal erosion will increase the water table gradient to the sea and result in a slight lowering of the ground water levels. Conversely coastal accretion will reverse this process. The spatial distribution of coastal erosion and accretion along the Sefton coastline and its likely impacts on groundwater levels are discussed. The modelling work described in this paper has identified the factors which have the largest effect on groundwater levels in temperate coastal dune systems.     

耐低温混菌降解苯系物的特性及菌种鉴定研究

以吉化双苯厂被硝基苯、苯系物（BTEX）污染的土壤为菌源,经过筛选驯化得到一组在低温条件（10℃）下可降解苯系物（BTEX）的混菌。室内研究表明,在10℃,pH=6.8,苯系物（BTEX）总质量浓度200mg·L^-1的条件下,84h后该菌对苯、甲苯、乙苯、二甲苯的降解率依次为93.2%、95.6%、91%、88.4%、对6种质量浓度的苯系物（BTEX）污染物中最难降解的苯进行降解动力学曲线模拟,当苯质量浓度小于17.48mg·L-1时,降解符合一级降解动力学,当苯的质量浓度为17.48～195.30mg·L^-1时,降解符合零级降解动力学、该混菌降解效果稳定、适应环境能力强,经80次传代后仍能保持良好的降解效果,且在6个不同地区含有不同背景组成的地下水中降解效果稳定、应用Biolog细菌自动鉴定系统和16SrDNA序列分析方法对降解率较高的3株菌B2、B4、B6作菌种鉴定,B2为嗜麦芽糖寡养单胞菌（Stenotrophomonas maltophilia）,B4为斑生假单胞菌（Pseudomonas maculicola）,B6为多刺假单胞菌（Pseudomonas spinosa）。     

基于LEAP模型的工业园区碳达峰路径：以南京某国家级开发区为例

工业园区是能源消费和碳排放的密集区域,推动工业园区碳达峰对国家早日实现碳达峰目标具有重要意义.以南京某国家级开发区为例,基于LEAP模型,设置基准情景（BAU）、非工业减排（S1）、全行业一般减排（S2）、全行业强化减排（S3）和深度减排（S4）共5类情景,分析各情景下的能源消费需求和CO2排放变化情况,评估各项措施的碳减排贡献,提出园区实现碳达峰目标的政策建议.结果表明,S2、S3和S4情景下能源消费需求和CO2排放量将分别于2035、2030和2028年达到峰值,能源消费需求峰值（以标煤计）分别为26.28、21.66和19.10万t,CO2排放峰值分别为75.35、59.34和53.24万t.工业是研究区域能源消费和碳排放的主要贡献行业,S2、S3和S4情景下工业能源消费和碳排放占比分别于2035年、2030年和2028年达到峰值57.1%、56.0%、53.6%和64.2%、66.2%和62.9%.工业能效提升的碳减排贡献最大,其次为经济增速放缓,交通新能源汽车推广和公共建筑节能的碳减排贡献不显著.综合考虑碳达峰时间和园区碳排放强度考核目标,建议将S3情景作为该园区碳达峰的实施...     

环境自动监测站固定式辐射监测仪性能测试与评价

参考计量技术规范《固定式环境γ辐射空气比释动能(率)仪现场校准规范》(JJF 1733—2018),对辐射环境空气自动监测站78台高气压电离室开展辐射特性测试。现场校准方面,仅88%的电离室满足1±0.2的响应范围要求;78台电离室的重复性均不超过1%,响应的非线性均不超过6.5%,符合规范要求。针对电离室开展辐射性能测试,发现电离室在9.0×10^-2~1.0×10⁹ μGy/h范围内的响应均不超过1±0.2;电离室对164 keV以上的光子的能量响应趋于1.0,对60 keV以下的光子无响应能力,而当光子能量在60~164 keV范围内时,响应曲线会因γ光子与电离室内部惰性气体的光电效应出现"鼓包";电离室不具备对核临界事故脉冲辐射的监测与警示能力;电离室能够在2 s内给出测量范围内的准确示值,但在分段电压的交界处,响应时间会延长至180~360 s;电离室的响应受环境温度、湿度变化的影响大小不足±0.01,表明电离室的环境适应性优良。