基于氨挥发因子方法的中国农田氨排放量估算

农田是氨的主要排放源,估算农田的氨挥发量可以明确其潜在的生态环境风险,为制定农田氨减排策略提供科学依据.通过文献收集,建立了包含867对观测值的中国农田氨挥发数据库,然后以氮肥施用量为自变量,氮肥施用引起的氨排放量为因变量,计算得到体现农业区、作物类型、肥料类型、土壤pH差异的氨挥发因子,采用独立样本进行验证,发现计算得到的氨挥发因子可以无偏地、较为准确地估算中国农田的氨挥发.不同区域、作物和管理措施下的氨挥发因子有显著差异,整体上,由于南方地区年均温和年降雨量均高于北方,导致南方的氨挥发因子高于北方,而碱性土壤的氨挥发因子高于中性和酸性土壤;与单施化肥相比,多数情况下施用有机肥可降低氨挥发因子,使用缓释控释肥或抑制剂可显著降低氨挥发因子;以单施化肥为例,水稻种植的氨挥发因子为9.9%~37.0%,高于蔬菜（2.2%~13.0%）和其他作物（3.3%~8.0%）.2015年中国农田由无机氮肥使用引起的氨排放总量为3.21 Tg,95%置信区间为2.92~3.46 Tg,其中,粮食作物和蔬菜占比最高,分别为66%和20%,豆科作物占比最低（0.8%）.由于气候、土壤、作物类型的差异,氨挥发呈现明显的空间异质性,长江中下游区排放量最高,而青藏区排放量最低.     

Volatilization and Biodegradation of VOCs in Membrane Bioreactors (MBR)

Volatilization and biodegradation are major competitive volatile organic compound (VOC) removal mechanisms in biological wastewater treatment process, which depend on compound specific properties and system design/operational parameters. In this study, a mathematical model was used to determine major removal pathways at various organic loading rates (OLR), solids residence time (SRT) and dissolved oxygen (DO) concentrations in a biological process for vinyl acetate. Model results showed that biological treatment process should be designed with long SRT, high OLR and low DO concentrations to maximize biodegradation and minimize volatilization of VOCs. Unless a VOC is toxic to microorganisms under the given conditions, low VOC emission rates are an inherent advantage of MBRs, which operate at higher OLR and longer SRT compared to conventional activated sludge process. A lab scale membrane bioreactor (MBR) was operated at varying OLR to investigate the relative volatilization and biodegradation rates for acetaldehyde, butyraldehyde and vinyl acetate. Synthetic wastewater containing three VOCs was introduced to the MBR. The DO concentration and SRT was maintained at 2.0 mg L^{− 1} and 100 days, respectively. The overall VOC removal rate was more than 99.7% for three VOCs at all the OLR. For vinyl acetate, the biodegradation rate increased from 93.87 to 99.40% and the volatilization removal rate decreased from 6.09 to 0.59% as OLR was increased from 1.1 to 2.0 kg COD m^{− 3} d^{− 1}. It was confirmed that a MBR can be a promising solution to reduce VOC emissions from wastewater.     

冷原子荧光法测定水中痕量汞的改进

对冷原子荧光法测定地表水及工业废水中汞的分析处理方法提出改进措施，改进的方法准，快，简，省，符合监测规范要求。     

植被在大气汞收支中作用的研究进展与展望

在汞的生物地球化学循环中,对于"源"和"汇"的认识还存在许多不确定性。大气汞收支不平衡的问题使得植被在汞循环中的作用日益凸现;开展植被在大气汞收支中作用的研究有助于为全球汞减排政策的制定提供参考。本文首先概述了植被中汞的来源和影响因素及其与大气汞的源汇关系;进而重点论述了植被参与大气汞收支的主要方式:凋落物沉降、生物质燃烧和植被表面与大气汞的动态交换,并阐述了植被在大气汞污染监测中的应用;最后在总结我国相关研究的基础上展望了未来的发展方向。     

中国四种土壤跳虫对重金属汞的响应

为了研究汞(Hg)对不同种类跳虫的毒性效应,将曲毛裸长()(Sinella curviseta)、四刺泡角()(Ceratophysella duplicispinosa)、小原等节()(Proisotoma minuta)、茉莉花长角()(Entomobrya sp.)4种中国优势跳虫物种分别暴露于Hg的6个浓度组中进行24 h,72 h-LC50急性毒性实验,利用Bliss法测得其4种跳虫的24h LC50分别为92.42、36.85、34.93、47.56 mg·L-1,其95%置信区间分别为68.57~168.6、29.61~43.53、25.57~44.94、34.33~65.11 mg·L-1;72 h的LC50为21.92、20.17、18.44、15.99 mg·L-1,其95%置信区间分别为16.18~29.82、6.64~29.81、13.87~26.45、10.03~21.37 mg·L-1。将小原等节()和茉莉花长角()分别暴露于Hg的6个相对较低浓度组中进行28 d生存繁殖实验,得到成虫存活数量和幼虫繁殖及生存数量。结果表明,4种跳虫中茉莉花长角()和曲毛裸长()对汞有较强的耐受性,小原等节()次之,四刺泡角()较弱。此外,小原等节()在Hg2+浓度为0.05 mg·L-1范围左右条件下有低剂量刺激效应。     

沈阳细河流域土壤和作物中汞的潜在生态危害及健康风险评价

为研究沈阳市细河流域土壤汞(Hg)的污染和健康风险状况,对该区土壤和农作物中Hg的含量和分布进行了调查和分析。采用Hakanson潜在生态风险危害指数法评价土壤Hg的污染状况,并利用健康风险评价模型对Hg通过不同暴露途径所引起的健康风险作出评价。研究结果表明,细河流域土壤Hg的潜在生态危害相对较大,其中43.21%样品处于中等危害程度,26.62%属于强及以上风险级别。健康风险评价模型计算表明,人体经食物摄取是土壤Hg暴露的主要途径,Hg日平均暴露剂量依次为食物摄取呼吸暴露皮肤暴露;成人和儿童的非致癌危害指数分别为0.315和0.713,均低于风险阈值1,表明Hg不会对人体造成健康危害。     

催化活性炭纤维脱硫除汞性能试验研究

采用活化后的活性炭纤维(ACFs)作为吸附剂以脱除SO2和Hg.为增加其吸附效果,对ACFs进行氨水溶液活化处理,试验采用不同浓度氨水溶液(8%和13%),利用XPS和软件计算处理得到ACFs表面元素分析和基本官能团的变化,通过动态脱除SO2和Hg吸附试验,证明氨水溶液活化ACFs是一种增加SO2和Hg吸附的有效措施.试验表明,氨水浓度并非越浓越好,而是存在一个最佳值.     

Quantitative and structural analyses of hazardous elements in Chinese medicines and herbs

Thirty samples of Chinese medicines and herbs were analyzed using instrumental neutron activation analysis (INAA) and X-ray diffraction (XRD) methods, mainly noting on the hazardous elements arsenic (As), mercury (Hg), chromium, antimony and cobalt. The three Niuhuang Jiedu Pian samples contained 8.6%, 8.3% and 2.2% As. Two out of four Liushen Wan samples contained approximately7% of both As and Hg. Despite being identically named, the other two Liushen Wan samples did not contain such high concentrations. Japanese Liushen Wan for children contained 1.2 ± 0.03% As and 31 ± 12 mg/kg Hg, whereas Liushen Wan for adults manufactured by another Japanese company contained 550 ± 22 mg/kg As and 1.2 ± 0.05 mg/kg Hg. All the chemical structural formulas of As and Hg in the high-concentration Niuhuang Jiedu Pian and Liushen Wan were realgar (As₄S₄), uzonite (As₄S₅) and cinnabar (HgS). Although the human body is generally not believed to absorb sulphides, continuous intake of these Chinese medicines is potentially no good because it is possible that some arsenic-sulfides will dissolve in gastric acid and then alter their chemical structures. Additionally, many herbs contained low concentrations of Hg, and their chemical structures were unknown.     

桐花树幼苗叶片生理生态指标对气态汞胁迫的响应

桐花树是我国主要的广布种红树植物,具有泌盐性。通过胁迫实验,研究桐花树幼苗叶片生理生态指标对气态单质汞(Hg0)胁迫的响应,以期了解红树植物吸收和富集气态汞的机制。结果表明:气态汞胁迫造成桐花树叶片可溶性糖含量、过氧化物酶(POD)活性下降;而丙二醛(MDA)、脯氨酸、超氧化物歧化酶(SOD)等指标上升;叶绿素含量、过氧化氢酶(CAT)活性出现先升高后降低的趋势,还原型谷胱甘肽(GSH)含量则先降低后升高。总之,虽然Hg0胁迫可增加桐花树幼苗叶的膜质过氧化程度,影响其生理代谢活动,但其叶片可通过调节抗氧化酶活性及还原型谷胱甘肽含量来提高自身抗氧化能力,进而提高对Hg0的抗性。     

黄石市城市大气和土壤中汞气污染研究

在对黄石市城市大气汞、土壤壤中气汞含量进行测定的基础上,采用内梅罗评价方法,对该地区的环境汞污染现状做了评价。评价结果显示,该地区大气以及土壤都受到汞污染．而且大气汞和壤中气汞受污染地带在同一地区,污染地带具有一定的地段性分布特征。同时对其污染原因进行了初步探讨。