印刷环节挥发性有机物无组织排放特征测定研究

对使用溶剂型油墨的凹版印刷设备和使用水性油墨的柔版印刷设备无组织排放的挥发性有机物(VOCs)浓度进行了实际监测,并采用计算流体动力学模拟无组织排放VOCs的收集效率。结果表明：(1)使用溶剂型油墨的凹版连续印刷过程非甲烷总烃(NMHC)最高均值达到5 975.67 mg/m³,约为使用水性油墨的柔版印刷(191.67 mg/m³)的31.2倍。虽然使用水性油墨可明显降低NMHC的排放,但其操作空间的浓度依然存在超过《工作场所有害因素职业接触限值第1部分：化学有害因素》(GBZ 2.1—2019)的现象。(2)印刷车间应该设置专门的调墨室,能缓解印刷车间内挥发性污染气体浓度的波动。(3)计算流体动力学模拟显示,设置合理的集气罩可有效降低VOCs的无组织排放,收集效率为70%～75%。     

贵阳市区大气降水中有机酸的研究

利用ICS-90常规离子色谱结合RFC-30型淋洗液在线发生器,对贵阳市区大气降水中的小分子有机酸进行了系统研究。测得贵阳市降水中的有机酸主要以甲酸[质量分数为(0.2-4.5)×10-6]、乙酸[质量分数为(0.6-5.3)×10-6]、草酸[质量分数为(0.1-4.9)×10-6]为主,其次是乳酸和丙酮酸,及少量丙酸和甲烷磺酸;有机酸对降水自由酸平均贡献为23.2%,占总阴离子的1.4%;通过比较贵阳市区有机酸前后二十年的变化,得出现阶段可能至少有近1/2乙酸和3/4甲酸来源于人类的活动,这说明有机酸人为源是其来源的重要组成部分。     

有机溶剂中温法溶出光伏组件封装材料乙烯-醋酸乙烯酯

采用有机溶剂邻二氯苯中温法溶出模拟光伏组件的封装材料乙烯-醋酸乙烯酯(EVA),探究了不同条件下EVA的溶出率及模拟组件的分离率,通过正交实验确定了有机溶剂中温法处理EVA的最佳条件.实验结果表明,在反应温度160℃、固液比(光伏组件个数与邻二氯苯体积之比,个/mL)4:100、搅拌转速800 r/min、反应时间24...     

Modeling the carbon dynamics of the La Grande hydroelectric complex in northern Quebec

A mechanistic semi-empirical carbon cycle model of the La Grande reservoir complex in northern Quebec, Canada was conceived in order to investigate the climate impact of such a large alteration of the continental water cycle. The model includes inputs from the drainage basin, organic matter release from flooded soils, CO₂ emissions across the water-atmosphere interface and sedimentation. Most input data stems from previous research by our group on those ecosystems. The model includes the seven reservoirs of the La Grande complex and was run for periods of 50 and 100 years. Terrigeneous dissolved, particulate and suspended soil carbon fluxes and concentrations were computed. Over 100 years, 31.3 × 10¹² g C are released from flooded soils, equivalent to 28-29% of inputs from the drainage basin. 40-74% of dissolved organic carbon is mineralized. CO₂ fluxes over 100 years are 50.5-79.8 × 10¹² g C, 46.4-67.9 × 10¹² g C more than in the absence of reservoirs. The increase in mineralization of organic matter and in CO₂ emissions is a result of the increase in cumulated water residence time due to the creation of the reservoirs. Changes in other carbon sinks and sources likely offset a part of this additional carbon flux to the atmosphere. In the first years following flooding of the reservoir, organic carbon release from flooded soils exceeds CO₂ emissions, implying the downstream export of large quantities of eroded soil organic carbon. After this initial period, CO₂ emissions are fuelled by organic carbon originating from the drainage basin.     

Chemical fluxes in time through forest ecosystems in the UK - Soil response to pollution recovery

Long term trend analysis of bulk precipitation, throughfall and soil solution elemental fluxes from 12 years monitoring at 10 ICP Level II forest sites in the UK reveal coherent national chemical trends indicating recovery from sulphur deposition and acidification. Soil solution pH increased and sulphate and aluminium decreased at most sites. Trends in nitrogen were variable and dependant on its form. Dissolved organic nitrogen increased in bulk precipitation, throughfall and soil solution at most sites. Nitrate in soil solution declined at sites receiving high nitrogen deposition. Increase in soil dissolved organic carbon was detected - a response to pollution recovery, changes in soil temperature and/or increased microbial activity. An increase of sodium and chloride was evident - a possible result of more frequent storm events at exposed sites. The intensive and integrated nature of monitoring enables the relationships between climate/pollutant exposure and chemical/biological response in forestry to be explored.     

生物有机除草剂防除水田杂草试验研究

采用田间试验方法,进行了生物稻壳粉、生物稻草粉2种生物有机除草剂对水田杂草的防效试验。结果表明,2种生物有机除草剂对水田杂草均有不同程度的防效,其中生物稻壳粉防效最好、经济效益最高,生物稻草粉防效和经济效益次之。该试验研究为生产有机水稻提供了新的除草方法。     

化工事故应急救援仿真演练系统的实施探讨

阐述了化工事故应急救援仿真的必要性及其国内外研究进展;提出整个系统的框架并设计系统开发过程的模型;分析了基于高层体系结构(HIA)的仿真系统的开发要点,给出参考开发工具,从而为整个系统开发提供思路.     

DISTRIBUTION AND GRAIN-SIZE PARTITIONING OF METALS IN BOVFOM SEDIMENTS OF AN EXPERIMENTALLY ACIDIFIED WISCONSIN LAKE1

ABSTRACT: A study of concentrations and distribution of major and trace elements in surficial bottom sediments of Little Rock Lake in northern Wisconsin included examination of spatial variation and grain-size effects. No significant differences with respect to metal distribution in sediments were observed between the two basins of the lake, despite the experimental acidification of one of the basins from pH 6.1 to 4.6. The concentrations of most elements in the lake sediments were generally similar to soil concentrations in the area and were well below sediment quality criteria. Two exceptions were lead and zinc, whose concentrations in July 1990 exceeded the criteria of 50 μg/g and 100 μg/g, respectively, in both littoral and pelagic sediments. Concentrations of some elements, particularly Cu, Pb, and Zn, increased along transects from nearshore to midlake, following a similar gradient of sedimentary organic carbon. In contrast, Mn, Fe, and alkali/alkaline-earth elements were at maximum concentrations in nearshore sediments. These elements are less likely to partition to organic particles, and their distribution is more dependent on mineralogical composition, grain size, and other factors. Element concentrations varied among different sediment grain-size fractions, although a simple inverse relation to grain size was not observed. Fe, Mn, Pb, and Zn were more concentrated in a grain-size range 20–60 tm than in either the very fine or the coarse fractions, possibly because of the aggregation of smaller particles cemented together by organic and Fe/Mn hydrous-oxide coatings.     

WETLAND ECOSYSTEM STUDIES FROM A HYDROLOGIC PERSPECTIVE1

ABSTRACT: Selected studies from the literature were reviewed to determine the extent of knowledge about the relationship between hydrology and wetland ecosystem studies. Wetland studies of chemical input-output relationships have been the most dependent on hydrologic data of all wetland investigations; yet, very few of these studies have attempted to measure all components of a wetland's water balance. Usually, unmeasured components were calculated as the difference between measured inputs and outputs. Ground water frequently was overlooked. Chemical input-output investigations primarily were concerned with determining the amount of input retained in the wetlands. Few studies also included direct measurement of biogeochemical processes within wetlands of elements that were part of simultaneous input-output investigations. The importance of uncertainties in chemical budgets that are due to uncertainties in hydrologic budgets has been addressed in very few wetland investigations. Although many studies have emphasized the importance of hydrology to wetland ecosystem research, few studies have documented this, so that hydrology remains one of the least understood components of wetland ecosystems.     

MUNICIPAL RESPONSES TO VOLATILE ORGANIC COMPOUNDS IN WISCONSIN GROUND WATER1

ABSTRACT: Contamination of ground water supplies with volatile organic compounds is a new and significant problem. Municipalities and their community water systems are often the first to discover ground water contamination because of the monitoring programs they are required to carry out. When contamination exceeds standards, some action is required. The responses of Wisconsin municipalities to volatile organic compounds that exceed standards in their ground water sources is described. Actions to protect human health are prompt, but the survey results indicate plumes of contaminated ground water are usually not treated. They may continue to migrate and contaminate other private and public wells.