内蒙古地区马铃薯中重金属残留状况与风险评价(英文)

[目的]对马铃薯重金属污染程度和对人体的健康风险展开风险评价。[方法]通过对内蒙古马铃薯样品的重金属监测,分析了马铃薯中的总砷、汞、镉、铅、铬、镍和铜等7种重金属的残留污染状况。[结果]内蒙古产区马铃薯重金属残留符合国家限量标准,重金属污染综合指数小于0.7,属于安全等级。铅和铬的污染相对严重,对综合污染指数的贡献相对明显。7种重金属THQ值及复合污染风险TTHQ值均小于1,表明该地区马铃薯中重金属的污染对人体健康造成的风险不明显。在以马铃薯为主粮的极大摄入水平下,铬的THQ值大于1,通过食用马铃薯摄入的铬含量可能引起人体的健康风险。不同采样区域,马铃薯中重金属对人群的健康风险存在差异性。[结论]该研究为马铃薯质量安全风险管理提供了客观科学依据。     

天津于桥水库流域河流表层沉积物中碳· 氮· 磷分布及污染评价

对流域内33个河流表层沉积物样点的总有机碳(TOC)、总氮(TN)和磷形态含量进行了测定,分析了沉积物中碳、氮、磷含量的分布特征及三者之间的相关性,并对于桥水库流域河流表层沉积物进行污染现状评价。结果表明:于桥水库流域河流表层沉积物TOC平均含量为0.99%,TN平均含量为0.15%,TP平均含量为1 904.93 mg/kg。相关性分析表明,沉积物TOC与TN呈极显著正相关(R2=0.794),TOC与草地面积比例呈极显著正相关,R2为0.685;TN和草地面积比例呈显著正相关(R2=0.392);TP与各种土地利用类型的相关性均不明显,但OP和Fe/Al-P与城镇居民用地面积比例呈极显著正相关,R2分别为0.664和0.698,与林地面积比例呈显著负相关,R2分别为-0.472和-0.403。有机指数和有机氮评价结果显示,有48.5%的采样点有机指数处于Ⅰ类水平,有39.4%和48.5%样点有机氮处于Ⅲ和Ⅳ类污染水平,表明于桥水库流域河流表层沉积物有机指数整体处于尚清洁及以上水平,受到有机污染程度较小,而流域内的有机氮污染相对较为严重。     

沙尘天气对兰州市城区环境空气质量影响研究

以2013年3月8 ～15日兰州市发生的系统性沙尘天气为例,分析了兰州市PM10、TSP以及能见度等污染物及气象因子对兰州市城区环境空气质量的影响.结果表明,此次沙尘天气甘肃始发地在河西走廊酒泉地区,主要受强冷空气影响,沙尘在风力影响下远距离输送,8日17：00在酒泉市发生时,大气最低能见度3.4 km,可吸入颗粒物最大浓度14.74 mg/m3,23：00影响到兰州等地,对甘肃省大部分地区影响较大,尤其对兰州市环境空气质量影响较大;受沙尘天气的影响,8 ～15日兰州市环境空气质量7d为重污染,1d为中度污染,首要污染物为可吸入颗粒物;能见度和可吸入颗粒物有明显的的负相关关系,湿度对能见度和颗粒物浓度的拟合存在影响.     

梧州地区降水和气温的气候特征

应用梧州地区5个站点1954～2011年逐月降水和平均气温资料,采用趋势分析、小波分析法,分析了近58年梧州地区降水和气温的变化趋势、变化周期性等气候特征。结果表明,近58年梧州地区年降水量、冬季降水量总体呈增加趋势,年降水量存在25年左右、10年左右的震荡周期,季降水量存在一个10年左右的振荡周期最为明显;年平均气温存在一个9～11年的振荡周期;近58年梧州全年、夏季、秋季、冬季平均气温总的趋势均表现为升高趋势,但升高的幅度不同,梧州全年平均气温上升幅度为0.152℃/10a,气候变暖表现明显;梧州58年来出现夏季严重多雨事件8次,严重少雨事件7次;出现秋季严重多雨事件3次,严重少雨事件2次。     

水土重金属污染的危害及防治对策

综述了水土重金属污染的现状,阐述了重金属污染对生物体的危害及防治措施,提出发展绿色农业是解决我国重金属污染的根本出路。     

奔驰W220型空气悬架系统分析

对奔驰W 220型空气悬架系统的结构、功能、工作原理进行分析,阐述了该悬架通过电脑接受传感器的信号并经处理后,由电脑控制执行机构以实现对气体、液体的控制,从而改变悬架刚度和阻尼,以满足车辆在不同道路状况下行驶对舒适性、操控性和通过性的要求。     

畜果结合生态养殖模式的研究

本研究系统探讨了果园和畜禽养殖的种养结合型生态模式,分析研究了“猪-沼-果”、“草-鸡-果”两种生态模式下的猪、鸡生产性能,畜舍空气质量以及苹果的产量和质量。研究结果表明:生态养殖模式下生长肥育猪和鸡的增重显著高于庭院养殖(P<0.05),分别提高了17.46%和29.28%;猪舍、鸡舍空气中的CO2和NH3比庭院猪舍、鸡舍显著降低(P<0.05);苹果产量比单纯果园平均分别提高28.97%和21.15%,含糖量分别相对提高6.79%和6.36%。     

The potential contribution of separation technologies to the management of livestock manure

Separation processes have a distinct role in the management of livestock slurries, but it is important to recognise their limitations. Such technology can direct certain manure components into a small volume of a concentrated stream which is useful for the production of organic products in subsequent processes. Equipment generally falls into systems based either on mechanical screening (which can produce a fibrous and seemingly dry product), filtration processes (producing a cake), or sedimentation leading to a sludge product. Although physical separation can remove up to 80% of the total solids content from livestock manures, this will only include a relatively small part of the soluble nutrient and of the reactive organic matter; this is particularly so where separation is based on screens. The complete removal of all suspended matter (total clarification) of an effluent is theoretically possible by settling — a decanter centrifuge will accelerate the process. This can remove most of the phosphorous, especially if coupled with chemical pre-treatment to raise the pH. However, the clarified stream still retains a significant polluting potential in terms of the residual nitrogen content (as ammonia) and potassium. Only membrane separation can greatly reduce the potassium concentration, but such technology is rarely suitable for the farm situation.     

Enhancement of photosynthesis and growth of tomato seedlings by forced ventilation within the canopy

A forced ventilation system that directs airflow upward or downward within a canopy was developed for plant culture in order to enhance photosynthesis and growth of the plant canopy. Tomato seedling canopies including the seedlings, growing medium, and a plastic tray were used for the experiments. In the upward and downward ventilation systems, air flows upward and downward, respectively, within the plant canopy; this is achieved by blowing and drawing air from holes (Ø 6 mm) made in plastic pipes positioned on the surface of the growing medium. A horizontal airflow system was used as a conventional system to compare the performance of the experimental ventilation systems. Using the upward and downward ventilation systems, the effects of air directions and air velocities on the CO₂ exchange rate of the tomato seedling canopy and the growth of the seedlings were compared with those observed using the conventional horizontal airflow system. The forced ventilation within the plant canopy enhanced the CO₂ exchange rate of the canopy and the dry masses of the seedlings by 1.4–1.5 and 1.2–1.3 times, respectively, as compared to the conventional horizontal airflow. When the leaf area index (LAI) increased from 1.2 to 2.4, there was only a 5% decrease in the CO₂ exchange rate per unit leaf area in the downward ventilation system, whereas there was a 20% decrease in the CO₂ exchange rate per leaf area in the horizontal airflow system. The coefficient of variation for the dry mass of the seedlings was higher in the downward system than in the other systems. These results demonstrate that forced ventilation within the canopy is an effective technique to enhance the gas exchange of the plant canopy and the consequent plant growth.     

野外昆虫与蚕种生产中的微粒子病防治

家蚕体内分离发现的 5种微粒子虫中 ,除家蚕微粒子虫 ( N osema bombycis)外未发现对家蚕具有较强致病性和胚传性的微粒子虫。野外昆虫中已有大量微粒子虫被发现 ,其中有些对家蚕也有很强的致病性和胚传性 ,但其原始寄主尚有诸多不明之处。所以 ,蚕种生产中防止野外昆虫微粒子虫对生产影响的根本途径在于控制家蚕微粒子虫污染的扩散和桑园治虫