二恶英类物质检测分析技术进展

介绍了同位素稀释气相色谱质谱联用和生物快速检测法测定二恶英类化合物的技术进展,概述了国际通用的二恶英类标准分析方法体系,提出了各方法的适用范围,综述了我国二恶英类化合物分析研究现状并对我国二恶英分析检测提出了建议。     

新形势下烧结厂环境影响评价要点分析

烧结是钢铁项目中污染物产生量较多的环节,本文通过分析其生产工艺、污染源强、环境风险、清洁生产以及执行标准,掌握烧结项目环境影响评价的要点,为企业日常管理提供参考。     

《水质 化学需氧量的测定 重铬酸盐法》新旧标准比较

比较了《水质化学需氧量的测定重铬酸钾法》新标准《HJ 828—2017》与旧标准《GB/T 11914—1988》的区别。相较旧标准,新标准主要对取样体积、硫酸汞加入方法和加入量、氯离子浓度粗判、方法检出限和检出下限、质量保证与质量控制等内容进行了修订。针对新标准中校核要求、方法检出限计算及平行双样质量控制方面存在的问题进行探讨。     

GB 19083-2010《医用防护口罩技术要求》标准解读

本文主要介绍新标准GB19083-2010的修订背景、新旧标准的差异对比,重点介绍影响口罩防护效果的重要指标—过滤效率和口罩密合性项目,并对生产厂家在应用标准时需要注意的事项加以说明。     

环境空气质量新标准对“十二五”目标完成的影响

十二五"期间全国PM_(10)浓度陡增导致了达标城市比例降低,影响了《国家环境保护"十二五"规划》空气质量指标的完成。通过对PM_(10)浓度时间和空间变化分析,得出《环境空气质量标准》(GB3095-2012)的逐步实施对全国PM_(10)浓度的异常变化有着显著影响。新标准的发布施行,促进了PM_(10)监测仪器和方法更新升级,大幅收严了监测数据统计的有效性,提升了监测数据的质量控制水平,从主观和客观上更加有效的提高了监测数据的精度。     

沈阳市地表水持续稳定达标关键措施与对策探讨

对沈阳市地表水环境特征及水质达标现状进行了分析,论述了地表水变化趋势,提出了实现地表水持续稳定达标的技术路径,要实现地表水环境质量持续稳定达标,必须采取优化经济结构及布局,持续推进污水集中控制,强化污染源治理,实施农村环境综合整治,提升河流生态环境质量和水体自净能力,强化水环境政策制度建设及环境监管等有效措施。     

模具CAD标准件库与资源库系统的设计

此文分析了传统方法建立标准件库的缺陷与存在的问题,提出了用作者开发的专用信息描述语言描述几何构形信息的思路。并介绍了基于信息描述语言建立标准件库和资源库的途径。     

Emissions from soil fumigation in two raised bed production systems tarped with low permeability films

Raised beds are used to produce some high-value annual fruit and vegetable crops such as strawberry in California (CA) and tomato in Florida (FL), USA. Pre-plant soil fumigation is an important tool to control soil-borne pests in the raised beds. However, fumigant emissions have detrimental environmental consequences. Field trials were conducted to evaluate emissions of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) in two different production systems with raised beds covered by different tarps. In the CA trial, InLine (60.8% 1,3-D and 33.3% CP) was drip-applied at 340 kg ha⁻¹ to 5 cm deep in the beds (30 cm high and 107 cm wide) tarped with polyethylene (PE) or virtually impermeable film (VIF). In the FL trial, carbonated Telone C35 (63.4% 1,3-D and 34.7% CP) was shank-applied at 151 kg ha⁻¹ to 20 cm deep in the beds (22 cm high and 76 cm wide) tarped with totally impermeable film (TIF). Emissions from tarped beds relative to furrows were contrary between the two trials. For the CA trial, the emission was 47% of applied 1,3-D and 27% of applied CP from PE tarped beds and 31% of applied 1,3-D and 15% of applied CP from VIF tarped beds, while that from uncovered furrows was <0.4% for both chemicals in both fields. In the FL trial, only 0.1% 1,3-D was emitted from the TIF tarped beds, but 27% was measured from the uncovered furrows. Factors contributing to the differences in emissions were chiefly raised-bed configuration, tarp permeability, fumigant application method, soil properties, soil water content, and fumigant carbonation. The results indicate that strategies for emission reduction must consider the differences in agronomic production systems. Modifying raised bed configuration and fumigant application technique in coarse textured soils with TIF tarping can maximize fumigation efficiency and emission reduction.     

A new synthesis of tetrachlorofluorodibenzo‐p‐dioxin

Abstract

The 1,2,3,4‐tetrachloro‐7‐fluorodibenzo‐p‐dioxin has been synthesized via condensation of 4‐fluorocatechol and pentachloronitrobenzene. This compound could be used as an internal standard for the analysis of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin by Chromatographic methods.     

GB/T5750-2006标准比色列缓冲法测定pH值的改进

本文依据GB/T 5750-2006标准比色列缓冲溶液比色法测定生活饮用水中的pH值,结合我实验室的检测经验对国标中指示剂的配制等重要环节进行了补充,并采用标准缓冲溶液比色法和玻璃电极法同时对自来水、河水、井水及矿泉水的pH值进行了测定,相对偏差在0.2%~1.3%之间,结果满意。