Trifluoroacetic Acid: Its Environmental Occurrence and Its Effects in Biota in Seasonal Wetlands Downwind from Sources of Precursor HCFCs and HFCs

三氟乙酸：前体 HCFC 和 HFC 来源顺风季节性湿地的环境存在及其对生物群的影响

• 批准号: 9708504
• 负责人: James Seiber
• 金额: $ 35万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 1999-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9708504&HistoricalAwards=false
• 关键词: Trifluoroacetic; Acid; Its; Environmental; Occurrence

9708504 Seiber This proposal was submitted to the Environmental Geochemistry and Biogeochemistry (EGB) solicitation NSF 96-152. The project described below is being jointly supported by the Divisions of Atmospheric Sciences and Earth Sciences. This project addresses the environmental occurrence of trifluoroacetic acid (TFA) and its effects in biota. TFA is a product of the atmospheric degradation of certain hydrochlorofluorocarbons and hydrofluorocarbons, which are replacement compounds for chlorofluorocarbons. The primary objectives of this project are: (1) To measure environmental concentrations of TFA in air, wet deposition, dry deposition, surface waters and plants at selected sites downwind from source regions, and to relate them to atmospheric concentrations of the precursor compounds; (2) To determine the uptake and effects of TFA in higher plans and the effects of TFA on microbes representative of seasonal wetlands under controlled exposure conditions. In addition, the experimental data on TFA occurrence and distribution will be compared with modeling efforts carried out at Harvard University. Seasonal wetlands in California and Nevada will be identified which might be particularly susceptible to effects of TFA from buildup over time. Environmental sampling will include both proximate downwind sites and more remote sites in the Sierra Nevada and Great Basin. TFA will be analyzed as its methyl ester using GC/MS, a technique recently developed by the PI. Controlled exposures of plants to known amounts of TFA will be conducted using misting chambers and long-term hydroponic exposures for selected wetland and crop species. The flux of gaseous and fog-dissolved TFA to and from plant surfaces, and the root uptake and emission of TFA from selected crop and wetland plant species will be measured to determine bioconcentration and toxic effects of TFA. For the microbial study, soils collected from wetland environments will be amended with TFA at several concentrations and the effect on microbial communities monitored by measuring microbial respiration.

9708504本提案已提交给环境地球化学和生物地球化学(EGb)征集活动NSF96-152。下文所述的项目由大气科学司和地球科学司共同支持。该项目讨论了三氟乙酸(TFA)在环境中的存在及其对生物群的影响。TFA是某些氯氟烃和氢氟烃在大气中降解的产物，它们是氯氟烃的替代品。该项目的主要目标是：(1)测量环境中空气、湿沉积、干沉积、地表水和来自污染源地区下风向选定地点植物中TFA的浓度，并将其与大气中前体化合物的浓度联系起来；(2)确定较高规划中TFA的吸收和影响，以及在受控暴露条件下TFA对季节性湿地代表微生物的影响。此外，关于TFA发生和分布的实验数据将与哈佛大学进行的建模工作进行比较。将确定加利福尼亚州和内华达州的季节性湿地，随着时间的推移，这些湿地可能特别容易受到TFA的影响。环境采样将包括内华达山脉和大盆地附近的顺风向站点和更偏远的站点。TFA将作为其甲酯使用GC/MS进行分析，这是PI最近开发的一种技术。对于选定的湿地和作物物种，将使用雾化室和长期水培暴露来控制植物对已知量的TFA的暴露。将测量气态和雾化TFA进出植物表面的通量，以及选定作物和湿地植物对TFA的根吸收和排放，以确定TFA的生物浓缩和毒性效应。对于微生物研究，从湿地环境中收集的土壤将被添加不同浓度的TFA，并通过测量微生物呼吸来监测对微生物群落的影响。