Winter Soil Respiration from Different Vegetation Patches in the Yellow River Delta, China

Vegetation type and density exhibited a considerable patchy distribution at very local scales in the Yellow River Delta, due to the spatial variation of soil salinity and water scarcity. We proposed that soil respiration is affected by the spatial variations in vegetation type and soil chemical properties and tested this hypothesis in three different vegetation patches (Phragmites australis, Suaeda heteroptera and bare soil) in winter (from November 2010 to April 2011). At diurnal scale, soil respiration all displayed single-peak curves and asymmetric patterns in the three vegetation patches; At seasonal scale, soil respiration all declined steadily until February, and then increased to a peak in next April. But, the magnitude of soil respiration showed significant differences among the three sites. Mean soil respiration rates in winter were 0.60, 0.45 and 0.17 μmol CO(2) m(-2) s(-1) for the Phragmites australis, Suaeda heteroptera and bare soil, respectively. The combined effect of soil temperature and soil moisture accounted for 58-68 % of the seasonal variation of winter soil respiration. The mean soil respiration revealed positive and linear correlations with total N, total N and SOC storages at 0-20 cm depth, and plant biomass among the three sites. We conclude that the patchy distribution of plant biomass and soil chemical properties (total C, total N and SOC) may affect decomposition rate of soil organic matter in winter, thereby leading to spatial variations in soil respiration.     

Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl-β-cyclodextrin amendments

The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO₃) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide (OCP)-contaminated paddy soil. After 180 days of incubation, total OCP biodegradation was highest in soil receiving the addition of nitrate and MCD simultaneously and then followed by nitrate addition, MCD addition, and control. The highest biodegradation of chlordanes, hexachlorocyclohexanes, endosulfans, and total OCPs was 74.3, 63.5, 51.2, and 65.1 %, respectively. Meanwhile, MCD addition significantly increased OCP bioaccessibility (p?<?0.05) evaluated by Tenax TA extraction and a three-compartment model method. Moreover, the addition of nitrate and MCD also obtained the highest values of soil microbial activities, including soil microbial biomass carbon and nitrogen, ATP production, denitrifying bacteria count, and nitrate reductase activity. Such similar trend between OCP biodegradation and soil-denitrifying activities suggests a close relationship between OCP biodegradation and N cycling and the indirect/direct involvement of soil microorganisms, especially denitrifying microorganisms in the anaerobic biodegradation of OCPs.     

NSGA Ⅱ在应急物资储备库选址中的应用

为了更好地应对突发事件,应做好应急物资的储备.应急物资储备库选址问题就成为优化应急物资储备的关键.应急管理中的应急物资储备库选址涉及到多方面的因素,已不是简单的单目标决策问题.针对此问题,构建了选址模型,并且引入NSGAⅡ解决模型中的多目标优化问题.求解后得出一系列Pareto最优解,其解空间分布均匀,并且具有良好的收敛性和鲁棒性,决策者可以根据实际情况从中选取最合适的解.对某应急物资储备库选址问题进行了讨论,结果证明此方法具有一定的实用性.     

基于风险指数RI的选址评价在LNG储备库中的应用

研究基于风险指数RI的选址评价方法,确定评价方法的框架和程序,并将该评价方法用于某拟建LNG储备库的选址.结果表明,沸腾液体扩展蒸气爆炸在拟建LNG储备库可能发生的事故中的后果最严重.以沸腾液体扩展蒸汽爆炸的计算结果为依据,在GIS中对LNG储备库进行缓冲区分析,得到直观显示的事故影响区域和影响对象.计算拟建LNG储备库的选址风险并与可接受风险水平进行比较,确定选址的合理性且适当调整周边布局.研究表明,基于风险指数RI的选址评价方法对合理确定重大工程选址是切实可行的.     

Parental phenols exposure and spontaneous abortion in Chinese population residing in the middle and lower reaches of the Yangtze River

Widespread use of phenols has led to ubiquitous exposure to phenols. In experimental animals, phenols increased resorptions, reduced live litter size and fetal body weights. However, there are limited epidemiological evidences of the relationships between exposure to phenols and pregnancy outcomes. We evaluated the associations between parental urinary levels of various phenols and spontaneous abortion in a Chinese population residing in the middle and lower reaches of the Yangtze River. A case-control study was conducted that included 70 case couples with medically unexplained spontaneous abortion and 180 control couples who did not have a history of spontaneous abortion and had at least one living child. Both parental urinary phenols were measured by ultra-high performance liquid chromatography-tandem mass spectrometry including bisphenol A (BPA), benzophenone-3 (BP-3), 2,3,4-trichlorophenol (2,3,4-TCP), pentachlorophenol (PCP), 4-n-octylphenol (4-n-OP) and 4-n-nonylphenol (4-n-NP). Compared with the low exposure group, there was an increased risk of spontaneous abortion with high paternal urinary PCP concentration [odds ratio (OR) = 2.09, 95% Confidence Interval (CI), 1.05–4.14], and maternal exposure to 4-n-OP and alkylphenol(s) also significantly increased the risk of spontaneous abortion (OR = 2.21, 95% CI, 1.02–4.80; OR = 2.81, 95% CI, 1.39–5.65, respectively). Our study firstly provides the evidence that paternal PCP exposure, maternal 4-n-OP and alkylphenol(s) exposure are associated with spontaneous abortion in humans.     

浸提分离法提取皂素清洁工艺研究

提出一种通过溶剂提取将游离皂苷与淀粉、纤维等成分分离，从源头上减少用水量、耗酸量和污染物排放量的皂素清洁生产工艺。首先对溶剂提取条件进行优化，得出最佳工艺条件为：90%（体积比）乙醇溶液，料液比1∶7，沸腾回流提取3 h，重复提取3次。然后通过气质联用（GC/MS）分析了皂素废水的有机物组成。研究结果表明，清洁工艺皂素产率为1.51%（降低3.82%），用酸量比传统工艺减少了71%，头道液COD浓度降低了46%，每100 g原料排放的COD总量下降了84%；皂素废水的有机物污染物主要为糠醛及其衍生物，清洁工艺废水的有机物含量更低，更易降解。     

液氨储罐泄漏中毒事故的个人风险分析

分析液氨储罐泄漏中毒事故的个人风险,为厂区的安全规划及防护措施方案的制订提供科学依据.以天津某化工厂液氨储罐为例,根据中毒事故个人风险计算方法计算液氨储罐周围区域的个人风险值,同时采用Surfer 8.0软件绘制该区域的个人风险等值线,实现风险分析结果在地图信息中的可视化.结果表明,液氨储罐泄漏可能会造成严重中毒事故;中毒事故个人风险值受该地区风向概率影响较大.首次将Surfer 8.0软件应用于绘制个人风险等值线,展示了该软件在表示个人风险方面很大的应用和推广价值.     

危险品运输泄漏引发的河流污染事故模拟研究

针对农药运输过程中发生翻车泄漏事故造成的河流污染,结合SMS软件中的二维有限元水动力模块RMA2及美国环境保护署推出的WASP软件进行模拟研究.利用RMA2模拟水在河流系统中的物理运动,通过一定的转换规则将RMA2输出的结果转变为WASP所需要的形式,运行WASP得到污染物浓度在空间和时间上的变化规律并加以分析.模拟结果表明:在泄漏事故后不久,污染物还没有完全扩散到泄漏点对岸;在一段时间后,在横向扩散的作用下,污染物开始整个横断面上蔓延,断面横向浓度梯度不断减小,但还没有达到完全混合;断面浓度最大值开始从泄漏一侧向河流中心迁移.最后,针对研究案例提出与模拟结果相应的预警分析和应急措施.     

季铵化木屑纤维素的制备及其对水中苯酚的吸附性能研究

以3-氯-2-羟丙基三甲基氯化铵(CTA)为醚化剂，对木屑纤维素进行了改性。探讨了改性木屑纤维素用量、pH值、吸附温度、吸附时间和苯酚初始浓度等因素对静态吸附效果的影响。结果表明，木屑纤维素经改性后，对水中的苯酚的吸附过程存在化学吸附，对水中的苯酚的吸附容量得到明显提高。     

一株产絮酵母菌废菌体对Cd2+的吸附特性

将一株产絮酵母菌(编号B-02号)发酵后的废菌体制成生物吸附剂,研究该生物吸附剂对废水中Cd2+的生物吸附特性。结果表明:(1)pH值对Cd2+会产生较大的影响,偏酸性(pH=4～6)条件利于吸附;该吸附剂对Cd2+吸附速率较快,8～10 min就可达到吸附平衡;(2)吸附剂的吸附动力学符合二级动力学模型,吸附Cd2+的实验数据对Langmuir等温式的拟合情况良好,吸附剂吸附Cd2+的最大吸附量为70.752 mg/g。用0.5 mol/L HNO3对吸附Cd2+的酵母菌进行解吸,解吸率可达89.7%。