Diflubenzuron residue and persistence on an oak forest after aerial application

Abstract

A twenty hectare forest block in central Pennsylvania was aerially sprayed with diflubenzuron (Dimilin 25W®) at the dose of 33.23g A.I./ha in 9.4 litres/ha. Leaf samples were collected from the upper and lower canopies of 27 oaks and understory within this block on the day of spray, May 29, 1991. Canopy leaves were also collected on May 31, June 10, July 29 and September 26, 1991.

Recovery of diflubenzuron residues on fortified canopy‐leaf and litter‐leaf samples using analytical techniques employed in this study averaged 87.4% (SE = 7.5%) and 66.2% (SE = 8.2%), respectively.

On the day of spray, diflubenzuron residues on the upper canopy, lower canopy and understory averaged 81.18, 39.65 and 8.35 ng/cm², respectively. Diflubenzuron residues on canopy‐leaf samples collected 2, 12, 61 and 120 days post‐spray averaged 14.83 (SE = 10.19), 16.75 (SE = 9.95), 12.84 (SE = 8.25) and 11.20 (SE = 7.52) ng/cm², respectively. Diflubenzuron residues on litter‐leaf samples collected after leaf senescence ‐ 169 and 323 days post spray contained measurable amounts of diflubenzuron in 51 and 59% of the samples, respectively. Of the samples with measurable amounts of diflubenzuron, residues averaged 1.36 (SE = 2.44) and 0.65 ng/cm² (SE = 0.73) respectively.     

Minimizing drift and exposure from knapsack sprayers

Abstract

An improved drift shield for attaching to the lance of conventional knapsack sprayer to reduce wind induced drift and operator exposure was designed and tested. The drift shield consists of a conical wire frame covered with polythene and has an annular opening at the point of attachment to the lance which allows air to be drawn into the shield while spraying. Tests conducted with winds in the range of 1.25–5.75 m/s show that wind can increase the width of spray swath from an unshielded lance, up to 4.3 times the normal swath in no‐wind condition. Use of a conventional shield contained the swath width within 3.5 times and the improved shield restricted the swath width to 3.1 times the normal swath. Spray deposit from an unshielded lance, within the normal swath decreased to as low as 45%, due to wind effects. However, use of the conventional, and the improved shields enhanced the spray deposit to 54.2% and 68%, respectively. The improved drift shield improved the spray pattern displacement (SPD) significantly (P<0.05) compared with the conventional shield and the unshielded lance when the wind speed exceeded 1.25 m/s. The improved shield decreased the off target drift by as much as 63% compared with the unshielded spray. It also decreased the quantity of pesticide deposit on the operator's body by 41–84% and thereby reduced exposure and improved safety.     

浅谈深圳市环境监督管理全覆盖移动执法系统的建设和应用

环境监督管理全覆盖移动执法系统,是利用现代无线通信技术、计算机技术等先进技术手段,利用手持终端(PDA)、手提电脑等设备,通过无线数字通信网的支持,实现在任何执法地点都可从后台业务系统中获取所需的业务数据、文字、图片、视频等信息,同时将现场执法的信息及时回传至后台系统中。本文介绍了移动执法系统的建设以及应用的情况。     

Multimedia fate modeling and comparative impact on freshwater ecosystems of pharmaceuticals from biosolids-amended soils

This study modeled the impact on freshwater ecosystems of pharmaceuticals detected in biosolids following application on agricultural soils. The detected sulfonamides and hydrochlorothiazide displayed comparatively moderate retention in solid matrices and, therefore, higher transfer fractions from biosolids to the freshwater compartment. However, the residence times of these pharmaceuticals in freshwater were estimated to be short due to abiotic degradation processes. The non-steroidal anti-inflammatory mefenamic acid had the highest environmental impact on aquatic ecosystems and warrants further investigation. The estimation of the solid-water partitioning coefficient was generally the most influential parameter of the probabilistic comparative impact assessment. These results and the modeling approach used in this study serve to prioritize pharmaceuticals in the research effort to assess the risks and the environmental impacts on aquatic biota of these emerging pollutants.     

化学降阻剂在山地环境中的应用研究

把山地环境划分为4种类型,并对各自的特点进行了分析.从导电机理和降阻机理两个方面分析了化学降阻剂的降阻功能,根据不同地质条件讨论了化学降阻剂的合理选择,并对化学降阻剂的应用方法和技术进行了研究,为山区防雷提供一定的参考价值.     

纳米TiO2的性能与应用研究

纳米二氧化钛(Nano-TiO2)因其具有粒径小、透明、紫外线吸收性能强以及优异的随角异色、光电催化和抗菌等优点而成为国内外科技工作者的研究热点。简要介绍了纳米TiO2的优异性能,详细论述了纳米TiO2在光催化处理污染物、抗菌剂、食品包装、药物添加剂、高级涂料、太阳能电池及防晒剂等方面的应用现状和研究进展,并对纳米TiO2的发展方向和应用前景进行了展望。     

旅游循环经济理念下的珠江源旅游区建设初探

旅游循环经济是发展旅游业一种新的指导思想,是实现旅游业可持续发展的新范式。针对珠江源旅游区的现状,根据旅游循环经济资源循环利用和保护并重的理念,探讨其在旅游区的林地系统利用建设、湿地系统利用建设、岩溶地貌系统利用建设、旅游服务设施系统利用建设方面的应用。     

斜拉桥支架法施工的自适应安全监测技术

介绍自适应控制的基本原理及其运用现状。根据斜拉桥的实际情况选用自适应控制形式,在主要部位埋设传感器和相关的测试仪器,明确监测时间并在实施中严格执行。依据实测结果对标高、应力、容重等参数按实际情况进行修正,得出施工过程中的受力状态,从而调整施工。算出主梁各节点理论施工预拱度变化曲线等数据并与实测值进行比较,反复修正。自适应法达到了仿真计算与实际施工过程保持一致的最佳施工控制效果。绥芬河斜拉桥的施工证明,自适应法是一种很适合斜拉桥支架施工安全监测的技术,值得推广应用。     

Odor Control for Land Application of Lime Stabilized Biosolids

Over three million dry metric tons of biosolids produced in the United States are land applied as Class B. Lime stabilization is employed for biosolids treatment at approximately 20% of the wastewater treatment plants because it is a simple and inexpensive process. During lime stabilization, the pH of sewage sludge is raised above 12 for pathogen inactivation and odor reduction. Lime dose and mixing have been found to greatly reduce odor generation from lime stabilized biosolids. A better quality biosolids product is less likely to create public opposition to land application programs. In this study, land application tests using Class B biosolids were conducted in order to determine whether better mixing can reduce odor generation during the land application of lime stabilized biosolids. The mixing quality of a treatment plant’s lime stabilized biosolids was improved by relocating the lime addition point, which prolonged the mixing time and produced a better mixed biosolids product. Based on field observations of land application, the poorly mixed biosolids were more odorous and offensive prior to incorporation. However, once incorporated into the soil, there was no appreciable odor difference between the biosolids. Another land application study was conducted to assess the odor of unincorporated Class A biosolids and compare it with incorporated Class A biosolids with the soil.     

中草药饲料添加剂的开发应用

中草药饲料添加剂具有较化学药物添加剂十分明显的优势,尤其在食品安全方面的绝对优势使其在畜牧业上地位日显重要.本文介绍了中草药饲料添加剂的类别、特点、机理及目前应用的情况.