重庆大气颗粒物与酸性降水关系研究

本文研究了重庆不同区域、不同季节、不同粒径的大气颗粒物的主要理化性能与酸性降水的关系,表明城区酸性细粒径颗粒物(IP、粒径<10μm)占 TSP 重量百分数为73％,大气颗粒物对酸性降水的缓冲能力较弱,通常冬(秋)季对降水酸度有一定贡献。     

广州市酸雨现状与发展趋势研究

叙述了广州小珠江三角洲范围历年来酸雨分布的特征及其发展趋势。分析表明,春季降水酸性最强,认为是局地源污染与外地源输送叠加的结果。酸性降水中起主要作用的阴离子是SO_4~(2-)和NO_3~-。尤以前者更为主要,NO_3~-的作用显著大于西南地区和上海地区;是美国的0.5倍。SO_4~(2-)/NO_3~-值低于西南地区2倍以上。广州市大气中H_2O_2及O_3浓度较高,光化学反应活跃。春季冷空气南下形成静止锋,有利于酸雨的形成。广州的酸雨已进入世界最强范围,与西欧、北美接近。     

广州白云山春季降水及广西苗儿山云雾水中有机弱酸的研究

利用离子色谱法测量了广州白云山春季降水及广西苗儿山云雾水中的甲酸和乙酸,并同时测定了降水中阴离子(F~-,Cl~-,SO_4~(2-),NO_3~-)和阳离子(Na~+,NH_4~+,K~+,Ca~(2+),Mg~(2+)。用多元逐步回归、多对多双重筛选回归及R聚类分析的多元统计的数学方法分析了降水中有机弱酸间及与阴阳离子间的关系。讨论了有机酸的来源及其对酸雨中酸度的贡献。     

Pesticides in rain

40 rainwater samples were collected in Hannover and near Peine (Lower Saxony, Germany) in 1992 using a wet-only collector. The samples were extracted by solid phase extraction and analyzed by GC/MS for 59 pesticides. 11 pesticides were found in more than 10 samples. The highest concentrations were observed for terbuthylazine (0.003 – 0.52 μg/L ), metolachlor (0.003 – 0.51 pg/L, mean: 0.10 μg/L), metalaxyl (0.006 – 0.48 μg/L, mean: 0.10 pg/L) and chlorothalonil (0.003 – 1.1 μg/L, mean: 0.16 μg/L). The concentrations show a seasonal dependence reflecting the application periods.     

Biomass Burning in the Amazon-Fertilizer for the Mountaineous Rain Forest in Ecuador (7 pp)

Background Biomass burning is a source of carbon, sulfur and nitrogen compounds which, along with their photochemically generated reaction products, can be transported over very long distances, even traversing oceans. Chemical analyses of rain and fogwater samples collected in the mountaineous rain forest of south Ecuador show frequent episodes of high sulfate and nitrate concentration, from which annual deposition rates are derived comparable to those found in polluted central Europe. As significant anthropogenic sources are lacking at the research site it is suspected that biomass burning upwind in the Amazon basin is the major source of the enhanced sulfate and nitrate imput. Methods Regular rain and fogwater sampling along an altitude profile between 1800 and 3185 m has been carried out in the Podocarpus National Park close to the Rio SanFrancisco (3°58'S, 79°5'W) in southern Ecuador. pH values, electrical conductivity and chemical ion composition were measured at the TUM-WZW using standard methods. Results and Discussion Results reported cover over one year from March 2002 until May 2003. Annual deposition rates of sulfate were calculated ranging between 4 and 13 kg S/ha year, almost as high as in polluted central Europe. Nitrogen deposition via ammonia (1.5–4.4 kg N/ha year) and nitrate (0.5–0.8 kg N/ha year) was found to be lower but still much higher than to be expected in such pristine natural forest environment. By means of back trajectory analyses it can be shown that most of the enhanced sulfur and nitrogen deposition is most likely due to forest fires far upwind of the Ecuadorian sampling site, showing a seasonal variation, with sources predominantly found in the East/NorthEast during January–March (Colombia, Venezuela, Northern Brazil) and East/SouthEast during July–September (Peru, Brazil). Conclusion Our results show that biomass burning in the Amazon basin is the predominant source of sulfur and nitrogen compounds that fertilize the mountaineous rain forest in south Ecuador. Recommendation and Outlook The mountaineous rain forest in south Ecuador has developed on poor and acid soils, with low nutrient availability. The additional fertilization resulting from anthropogenic biomass burning constitutes a significant disturbance of this ecosystem, its functioning and biodiversity. Thus it is planned to employ isotope analyses for quantifying the pathways of nitrate and sulfate deposition in these natural forests.     

纳米TiO2光催化降解酸性粒子元青溶液的研究

对纳米 Ti O2 光催化氧化法降解酸性粒子元青溶液进行了试验研究。结果表明 ,反应符合一级反应 ,反应速率常数为2 .9× 10 - 3min- 1。确立的最佳工艺条件 :催化剂的用量为 4.0 g·L- 1 ,溶液的 p H为 6.3 8,空气的体积流量为 12 0 m L· min- 1 ,在此最佳工艺条件下 ,酸性粒子元青的降解率达到 92 .3 %。且测得反应的表现活化能 Ea为 -17.9k J· mol- 1 。     

九寨沟公路和栈道降雨径流污染负荷过程的研究

对九寨沟国家公园中的公路和游客栈道进行了人工降雨试验的设计、操作和测试数据分析.模拟试验选择6处公路和栈道试验区,采用人工降雨方法模拟雨量出现概率60%、历时30 min的降雨.试验按3 min间隔对各试验场降雨径流带出的总磷负荷进行现场监测.研究结果提供了在具有代表性的降雨条件对总磷营养物输出的定量估计.尤其对公路和栈道降雨径流特征获得了认识:污染物初始冲刷浓度期延续约3 min;在降雨强度不变的情况下,污染物负荷率接近常量.大部分污染物负荷可由出现频率较大的小降雨事件输出.表明研究结果提供了一种思路,即可采用平均负荷方式取代过去的平均浓度方式去构建公路和栈道的负荷模型.     

模拟酸雨对杜仲抗性生理及药用有效成分含量的影响

研究了模拟酸雨对杜仲抗性生理及药用成分绿原酸、桃叶珊瑚甙、总黄酮含量的影响.结果表明,春夏秋季在系列模拟酸雨胁迫下,杜仲叶叶液pH值、K 、Ca2 含量随酸雨pH值降低而降低,呈显著正相关;杜仲叶膜保护酶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和膜保护物质抗坏血酸(AsA)含量在春夏两季随酸雨pH值降低呈单峰曲线型变化,秋季则均随酸雨pH值降低而降低,且呈显著正相关;抗性物质脯氨酸(Pro)含量春夏两季随酸雨pH值降低而升高,呈显著负相关,秋季则在pH3.0和2.5的强酸雨胁迫下急剧降低;膜脂过氧化产物丙二醛(MDA)含量无论春夏秋季均与酸雨pH值呈显著负相关;春季仅pH2.5的强酸雨对杜仲叶绿原酸、桃叶珊瑚甙和总黄酮等药用成分含量影响较大,夏秋两季各药用有效成分则均随酸雨pH值降低而降低,呈显著正相关.图1表2参27     

佛山市区大气降水pH值的时空分布及酸雨成因

根据大气降水监测资料，分析了佛山市区大气降水pH值的时间变化规律和空间分布特征，探讨了佛山市区酸雨的主要形成原因和影响因素，在此基础之上，提出了防治酸雨污染的对策。