西安市商场建筑室内外颗粒物污染状况调查

为了解西安市商场建筑室内外颗粒物的污染状况,采用德国Grimm气溶胶光谱仪对该市10家商场的室内外颗粒物浓度进行测试。结果发现,10家商场室内外PM10和PM2.5浓度都不同程度超过了相关标准规定的浓度值,PM10和PM2.5的室内超标率分别为66.4%和71%,室外超标率分别为73.8%、71.6%。室内外颗粒物浓度I/O比值均小于1,出现(I/O)PM10<(I/O)PM2.5<(I/O)PM1.0的规律。同时,室内可吸入颗粒物主要以对人体伤害较大的细颗粒物为主。     

十溴联苯醚对大型蚤和发光菌的毒性研究

利用发光菌和大型蚤2种不同层级的水生生物研究十溴联苯醚(BDE-209)对其的毒性,为多溴联苯醚的生态风险控制提供基础数据和技术参数。大型蚤毒性试验结果表明:BDE-209在24 h和48 h内不足以引起大型蚤死亡,48-EC50>10 mg/L,属于低毒;BDE-209暴露浓度为1 mg/L时,对大型蚤的生长和繁殖没有显著影响。但BDE-209暴露浓度≥10 mg/L时对大型蚤的生存和繁殖会产生较大影响,这是由于BDE-209在慢性试验过程中降解成了多种毒性更强的低溴联苯醚。发光菌急性毒性试验表明,BDE-209对发光菌的剂量-效应曲线为非线性,且急性毒性较小,浓度越高,抑制率越高,高浓度下对发光菌的抑制率变化很小。     

河流环境质量现状及污染防治对策

水作为一种宝贵的自然资源,在人类生活、生产中起着重要作用。随着社会经济迅速发展,水资源面临着污染严重、资源枯竭等问题。河流作为一种重要的淡水资源,其环境质量的好坏关系到人类的生活水平的高低。本文对深圳市宝安区三条河流环境质量现状进行监测,分析了造成三条河流污染的主要原因,并针对污染原因提出了污染防治对策。     

溢油分散剂及其乳化原油对海洋微藻的急性毒性效应评价

以96 h半致死效应浓度(96 h-EC50)为指标,比较测定了3种溢油分散剂(oil spill dispersant,OSD)、原油的水溶性成分(water accommodated fraction,WAF)以及OSD乳化作用下原油的水溶性成分(dispersed water accommodated fraction,DWAF)对海洋微藻的急性毒性效应。结果表明:所测试3种OSD中,RSA-11型和ZHY-2型的毒性明显低于RSS-6型的毒性;而RSA-11型OSD的毒性高于组成该OSD单一表面活性剂的毒性,呈现明显的协同作用;同时,OSD与原油共存时的DWAF的毒性既高于OSD单独存在时,也高于原油单独存在时WAF的毒性,表明溢油时加入OSD会增强原油对海洋微藻的毒性。     

基于邓肯-张模型的黏土心墙堆石坝有限元数值模拟分析

基于邓肯-张非线性弹性材料模型,对云南省某在建黏土心墙堆石坝逐层填筑施工和正常蓄水+9度地震作用两种工况情况下的坝体应力和变形进行了有限元数值模拟与分析。结果表明:由于存在"内部拱效应",过渡层出现应力集中,心墙出现应力迅速降低;填筑竣工后的大坝应力分布和位移符合一般规律,但9度地震作用下可能会引起大坝失稳,建议采取一定的工程措施,提高坝坡的抗震稳定性。     

铁杉属的起源、扩散与传播——基于化石证据【封面文章】

铁杉属是松科的重要组成部分,具有典型的北美—东亚间断分布特征。关于该属的起源、扩散与传播,目前存在较多的争议。本次研究收集了亚洲铁杉属大化石记录,整合了铁杉属花粉记录,获取地质历史时期该属在中国的分布,推测该属的起源和传播路径。该属大约起源于晚白垩世的西欧地区,于马特斯里赫特期—达宁期通过欧亚大陆传播到中国,而在古新世—始新世时期通过北大西洋陆桥传播到北美。早始新世以后北美与东亚的铁杉属植物可以通过白令陆桥进行物种交流,当图尔盖海峡在渐新世干涸后,铁杉属能够通过西西伯利亚和中亚哈萨克斯坦地区在欧亚大陆上交流。在晚中新世铁杉属可以通过北大西洋陆桥进行交流。依据化石记录推断的铁杉属起源和传播的结果与分子学研究存在一定差异,需要更多的铁杉属化石记录及分子学研究提供更可靠的证据。     

聚丙烯环生物滴滤塔去除实际市政污水厂硫化氢性能及微生物群落分析

在非稳态条件下,采用AAO剩余污泥为种泥、聚丙烯环为填料启动生物滴滤塔,处理实际市政污水厂细格栅H2S恶臭气体.研究了生物滴滤塔的启动、稳定阶段的运行模式,在空床停留时间为14 s,进气浓度2. 02～319. 19 mg·m-3,环境温度为7. 8～32. 5℃条件下,平均出气浓度为13. 08 mg·m-3,平均去除率达到91. 8%,最高去除负荷达到78. 37 g·(m3·h)-1.在247d运行中,监测到生物滴滤塔压降在长期运行中维持稳定在96 Pa·m-1.高通量测序表明,生物滴滤塔内的微生物群落发生了改变,Shannon指数由4. 99降低至3. 75,但Pseudomonas和Thiobacillus等功能菌的存在解释了生物滴滤塔较好的去除性能.结果表明,在非稳态条件下,以AAO剩余污泥为种泥的生物滴滤塔可实现H2S的高效去除;聚丙烯环作为填料可以在长期运行中维持稳定的压降;微生物群落在长期高浓度的H2S环境中,多样性降低,但降解性能可以得到提高.     

川西甘孜藏族自治州1961—2015年日照时数变化特征分析

甘孜藏族自治州(简称甘孜州)位于青藏高原东南缘,是一个气候敏感区和环境脆弱区.利用多年气象数据探讨该区气候变化趋势对研究区环境保护、灾害防治和发展规划有重要意义.本文基于1961—?2015年甘孜州11个气象站点的日照时数、气温、降水、相对湿度和风速数据,通过一元线性回归、5 a滑动平均、累计距平、Mann-Kendall(M-K)突变检验和样条函数插值分析方法,研究该地区年际、季度的日照时数时空变化特征以及与其他气候因子之间的关系.研究结果表明:(1)平均日照时数在年际和季度尺度上呈减少趋势,减少速率分别为25 h·(10a)?1(年际)、6.4 h·(10a)?1(春季)、6.8 h·(10a)?1(夏季)、6.9 h·(10a)?1(秋季)、6.3 h·(10a)?1(冬季).(2)空间分布上,德格的西部地区日照时数减少最快,而乡城县等极少数地区出现日照时数增加的趋势.(3)年际日照时数在1989年发生突变,在季节尺度上春季、夏季、冬季发生突变的年份分别为1989年、1991年和1994年,秋季突变不明显.(4)日照时数与气温、降水量、相对湿度均呈负相关关系,相关系数分别为??0.2、??0.6、??0.5;日照时数与风速呈显著正相关关系,相关系数为0.6.本研究可为甘孜州地区1961—?2015年的气候变化提供数据支持.     

Fish forewarning of comprehensive toxicity in water environment based on Bayesian sequential method

Environmental impact of pollutants can be analyzed effectively by acquiring fish behavioral signals in water with biological behavior sensors. However, a variety of factors, such as the complexity of biological organisms themselves, the device error and the environmental noise, may compromise the accuracy and timeliness of model predictions. The current methods lack prior knowledge about the fish behavioral signals corresponding to characteristic pollutants, and in the event of a pollutant invasion, the fish behavioral signals are poorly discriminated. Therefore, we propose a novel method based on Bayesian sequential, which utilizes multi-channel prior knowledge to calculate the outlier sequence based on wavelet feature followed by calculating the anomaly probability of observed values. Furthermore, the relationship between the anomaly probability and toxicity is analyzed in order to achieve forewarning effectively. At last, our algorithm for fish toxicity detection is verified by integrating the data on laboratory acceptance of characteristic pollutants. The results show that only one false positive occurred in the six experiments, the present algorithm is effective in suppressing false positives and negatives, which increases the reliability of toxicity detections, and thereby has certain applicability and universality in engineering applications.     

Copper stimulates the incidence of antibiotic resistance, metal resistance and potential pathogens in the gut of black soldier fly larvae

The black soldier fly larvae (BSFL) have been successfully applied to treat various organic wastes. However, the impacts of heavy metals on antibiotic resistance in the BSFL guts are poorly understood. Here, we investigated the effect of copper (exposure concentrations of 0, 100 and 800 mg/kg) on the antibiotic and metal resistance profiles in BSFL guts. A total of 83 antibiotic resistance genes (ARGs), 18 mobile genetic elements (MGEs) and 6 metal resistance genes (MRGs) were observed in larval gut samples. Exposure to Cu remarkably reduced the diversity of ARGs and MGEs, but significantly enhanced the abundances of gut-associated ARGs and MRGs. The levels of MRGs copA, czcA and pbrT were dramatically strengthened after Cu exposure as compared with CK (increased by 2.8–13.5 times). Genera Enterococcus acted as the most predominant potential host of multiple ARG, MGE and MRG subtypes. Meanwhile, high exposure to Cu aggravated the enrichment of potential pathogens in BSFL guts, especially for Escherichia, Enterococcus and Salmonella species. The mantel test and procrustes analysis revealed that the gut microbial communities could be a key determinant for antibiotic and metal resistance. However, no significant positive links were observed between MGEs and ARGs or MRGs, possibly suggesting that MGEs did not play a crucial role in shaping the ARGs or MRGs in BSFL guts under the stress of Cu. These findings extend our understanding on the impact of heavy metals on the gut-associated antibiotic and metal resistome of BSFL.