Persistently highest risk areas for hantavirus pulmonary syndrome: potential sites for refugia.

Interannual variation in the number of cases of human disease caused by hantaviruses in North America has been hypothesized to reflect environmental changes that influence rodent reservoir populations. This hypothesis postulates that when cases are rare reservoir populations are geographically restricted in patches of suitable habitat. Identifying these sites, which is needed to test the hypothesis, has proven to be a challenge. Satellite imagery of the U.S. Southwest has shown associations among the likelihood of human hantaviral disease and increases in the rodent populations, as well as increased prevalence of Sin Nombre virus (SNV) in rodent populations. In this study we characterize local areas that had environmental signatures that persisted as predicted highest risk sites for human disease through much of the 1990s. These areas represent a small percentage (0.3%) of the region. Exploratory analyses indicate that these areas were not randomly distributed, but were associated with certain landscape characteristics. Characteristics of elevation, slope, aspect, and land cover were associated with persistent high risk. Using multivariate Poisson regression to control for confounding effects, sites with deciduous- or mixed-forest land cover on moderate to steep slopes (>5 degrees) above 2130 m elevation were associated with increasing numbers of years at highest risk. These are candidate locations for refugia. Sites associated with cleared ground or shrubland were less often associated with high risk compared to reference conditions. The seasonal patterns of vegetation growth in persistently high-risk areas were compared to matched locations using MODIS (moderate resolution imaging spectroradiometer) NDVI (normalized difference vegetation index) during a time of a severe drought in the region from 2002 to 2004. Despite the drought and regardless of land cover, the NDVI in persistently highest risk areas had an early onset, with significantly higher levels of green vegetation that lasted longer than at comparable sites. These observations identify locations that can be monitored for the abundance of P. maniculatus and presence of SNV. If these sites are refugia, we predict they will be occupied by infected deer mice when other monitored sites are unoccupied.     

Pressure-assisted chelation extraction of lead from contaminated soil

Soil contamination by metallic elements including lead occurs frequently. Contaminant metals in soil pose a serious risk to public health and groundwater supplies. Extraction using chelants is seen as a remediation option; however, it is often hampered by access to the contaminants that are shielded by the soil matrix. We have developed a novel extraction technique that utilizes a mildly elevated pressure in consecutive cycles of compression and decompression along with a chelating agent for the soil slurry. Complete extraction of 3300 mg/kg of Pb from soil was achieved by 100 mM of EDTA (ethylenediaminetetraacetic acid) in 10 min using 20 pressure cycles at 150 psi (10 atm). Extraction was studied according to pressure, number of pressure cycles, chelant concentration, solid content, pH, agitation, and use of consecutive washings. Heightened extraction is attributed to fracturing of the soil particles that leads to enhanced contaminant exposure to the chelating agent.     

Potential of different species for use in removal of DDT from the contaminated soils

Dichlorodiphenyltrichloroethane (DDT) and its main metabolites, p,p'-DDD and p,p'-DDE (DDTs in this study included DDT, DDD and DDE), are frequently detected in agricultural soils even though its usage in agriculture was banned in 1980s or earlier. In this study, eleven plants including eight maize (Zea mays) cultivars and three forage species (alfalfa, ryegrass and teosinte) widely cultivated in China were grown in the soils spiked with DDTs to investigate their potential for removal of DDT from the contaminated soils. The plants varied largely in their ability to accumulate and translocate DDTs, with the bioconcentration factor (BCF; DDT concentration ratio of the plant tissues to the soils) ranging from 0.014 to 0.25 and the translocation factor (TF; DDT concentration ratio of the shoots to the roots) varying from 0.35 (Zea mays cv Chaotian-23) to 0.76 (Zea mays spp. mexicana). The amount of DDT phytoextraction ranged from 3.89mug (ryegrass) to 27.0mug (teosinte) and accounted for <0.1% of the total initial DDTs spiked in the soils. After 70d, the removal rates reached 47.1-70.3% of the total initial DDTs spiked in the soils with plants while that was only 15.4% in the soils without plant. Moreover, the higher removal rates of DDTs occurred at the first 20d of experiment, and then the removal rate decreased with time. The highest amount of DDTs phytoextracted was observed in teosinte, followed by Zea mays spp. mexicana, but the highest removal rate of DDTs was found in maize (Zea mays cv Jinhai-6). Even though phytoextraction is not the main removal process for DDTs, the plant species especially Zea mays cv Jinhai-6 showed high potential for removing DDTs from the contaminated soils.     

杭州城市大气消光系数和能见度的影响因子研究

为了解杭州市能见度下降与大气污染之间的关系，在2001年5月至2002年5月对不同粒径的颗粒物（PM10、PM2.5）的质量浓度进行了观测，结合晴天天气条件下的大气能见度，推算污染物和水汽分子对大气的消光散射，发现细微颗粒物的散射消光特性对杭州市能见度下降起主要作用，并得到能见度与细微颗粒物浓度比值（PM2．5／PM10）的关系；分析了大气能见度和消光系数与PM2．5／PM10和相对湿度的相关系数。     

各种影响因子对电解法预处理医药废水的影响研究

探讨了电解法预处理医药废水时停留时间、电解电压、废水初始浓度、温度和废水pH值等影响因子对去除色度、COD和提高废水可生化性等处理效果的影响,并考察了其应用于工业实际废水处理的可行性.实验结果表明:电解法更适合高浓度医药废水的处理,色度的去除率可达到90%以上;电解时间宜控制在40～60 min;电解电压越高,废水COD和色度去除效果越好;在实验温度范围内,温度对色度和COD去除率的影响不大;废水pH值为7.5时电解效果最佳,工程运用宜控制在6～9之间.     

城市生活垃圾问题研究的系统动力学方法

利用被称为战略与策略实验室的系统动力学方法,建立了城市生活垃圾问题的系统动力学研究模型;以北京市为实例,探讨了垃圾排放及污染随人口和经济发展的变化,以及污染和占地损失、绿色GDP核算、居民家庭、企事业单位生活垃圾与建筑垃圾组合收费方案等问题.     

Organic compounds and trace metals of anthropogenic origin in sediments from Montego Bay,Jamaica: assessment of sources and distribution pathways

Surface sediments throughout Montego Bay, Jamaica were collected in 1995 and analyzed for their trace metal and trace organic contaminant content. A variety of trace metals, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, coprostanol as well as chlorinated hydrocarbons such as pesticides and polychlorinated biphenyls were detected and provide evidence for several anthropogenic inputs to the bay. Two main sources of these chemicals are the Montego River and the North Gully, the latter being more significant. Particle-associated pollutants were found to be distributed along the Montego River plume, as well as being transported by the prevailing water currents to the South-Western sections of the bay, probably through re-suspension of enriched fine sediments from the North Gully outfall area.     

于桥水库富营养化防治前置库对策可行性研究

于桥水库库前区墙截老河道入口，形成一个近９ｋｍ￣２，容积达２０００万ｍ￣３～２５００万ｍ￣３的前置库，可充分发挥其物理、生物、化学的综合作用，延长入流水在前置库区的滞留时间，降低流速，均化流场使入流水在前置库区得到净化，大量的泥沙及营养盐截留在前置库区，从而使进入主库的营养盐含量大幅度降低，抑制主库中藻类的过度繁殖，起到防治或减缓于桥水库富营养化的作用。     

邻苯二甲酸二丁酯对KM小鼠神经行为学的影响及芒果苷的拮抗作用

探究邻苯二甲酸二丁酯(DBP)对小鼠神经行为学影响的剂量-反应关系,以及芒果苷(MAG)的拮抗作用。36只性成熟雄性KM小鼠随机分为4组:(1)生理盐水组,(2) 5 mg·kg~(-1)DBP组,(3) 25 mg·kg~(-1)DBP组,(4)125 mg·kg~(-1)DBP组,实验周期28d。应用国际通用的高架十字迷宫(EPM)和旷场实验(OFT)检测DBP暴露后KM小鼠的神经行为学变化;通过脑组织病理学切片,检测KM小鼠的靶组织脑海马CA1区病理变化;通过测定活性氧(ROS)、谷胱甘肽(GSH)、丙二醛(MDA)、DNA-蛋白质交联系数(DPC),检测KM小鼠的脑海马组织氧化损伤水平。以MAG作为抗氧化剂,36只KM小鼠随机分为4组:(1)生理盐水组,(2) 50 mg·kg~(-1)MAG组;(3) 125 mg·kg~(-1)DBP组;(4) MAG+DBP组,进行神经行为测试,同时评估各组KM小鼠脑海马组织氧化损伤。与对照组比较,随着DBP暴露剂量的升高,125 mg·kg~(-1)DBP组KM小鼠进入开放臂次数减少,停留时间偏短,运动距离较短,运动轨迹偏离中央区域;脑海马CA1区锥体神经细胞排列紊乱,细胞形态肿胀变形,树突缩短甚至消失;且脑系数下降,ROS、MDA含量及DPC系数逐渐上升,GSH含量逐渐降低,且差异均有统计学意义(P0.05, P0.01);加入拮抗剂MAG处理后,与125 mg·kg~(-1)DBP组比较,MAG+DBP组小鼠神经行为学出现一定程度的缓解,脑海马CA1区病理程度减轻,脑系数上升,ROS、MDA含量及DPC系数出现一定程度的下降,GSH含量出现一定程度的上升,且差异均有统计学意义(P0.05, P0.01)。DBP所致小鼠的神经行为学变化可能与脑海马组织的氧化损伤有关; MAG可通过降低小鼠脑组织氧化应激水平,对DBP暴露所致的小鼠神经行为学影响起到一定的保护作用。     

植物对酞酸酯的敏感性

采用发芽试验和温室盆试验等方法，研究了酞酸酯（ＤＢＰ、ＤＥＨＰ）对番茄等１２种蔬菜以及水稻、小麦和油菜的影响。结果表明：酞酸酯（１０ｍｇ／１）对种子发芽率无明显影响，但对幼苗形态特征有一定作用。电镜观察表明：受害叶片叶绿体数量减少、结构改变。初步讨论了酞酸酯的理化性质与作物受害的关系，划分了蔬菜对酞酸酯的敏感性顺序。