Nitration and hydroxylation of benzene in the presence of nitrite/nitrous acid in aqueous solution

This paper studies the nitration and hydroxylation of benzene in the presence of nitrite/nitrous acid in aqueous solution, both in the dark upon addition of hydrogen peroxide and under 360 nm irradiation. In both cases the detected transformation intermediates were phenol (P), nitrobenzene (NB), 2-nitrophenol (2NP) and 4-nitrophenol (4NP). P and NB directly form from benzene, and the initial formation rate of P is at least an order of magnitude higher than that of NB. In our experiments nitrophenols arise from P nitration, as can be inferred by their time evolution and isomer ratio (2NP:4NP=60:40, 3NP below detection limit). Nitrophenols may also form upon hydroxylation of NB, but in a different ratio (2NP:3NP:4NP=45:30:25). The detection of 3NP is thus a marker for the hydroxylation of NB, since this isomer is not formed in P nitration processes. The formation rates of P and NB increase with decreasing pH, both in the presence of HNO₂ + H₂O₂ in the dark (which produce HOONO) and in the presence of NO₂⁻/HNO₂ under irradiation. In the former case the pH dependence reflects the formation rate of HOONO. In the case of the irradiation experiments the pH effect can be accounted for by the higher molar absorbivity and photolysis quantum yield of nitrous acid when compared with nitrite. Interestingly, benzene does not react with HNO₂ alone in the dark. An important feature of benzene nitration in the presence of NO₂⁻/HNO₂ under irradiation is that the process is not inhibited by the addition of hydroxyl scavengers, differently from the case of phenol nitration. This finding indicates that nitrite irradiation might lead to the nitration of certain aromatic compounds in natural waters even in the presence of natural hydroxyl scavenging agents, which are usually thought to limit the environmental role of many photochemical processes.     

烟气黑度多媒体联网监测系统

系统实现了64个预置点的烟气排放林格曼指数自动监测功能，系统可以工作在手动模式和自动扫描模式。每一个预置点都有3个参考区域，通过扣除背景有效地降低了误报概率，对于超标数据采取本地数据库和远程数据库同时存储的方法，远程数据库提供了基于局域网上的分级查询和统计，超标图像存储采用JPEG图像格式和自定义的无损压缩格式。     

网格监测统计积分模式的推导与应用

把大气污染物的空间分布看成是连续变化的超曲面,采用积分法推导网格监测点位均值的积分模式,并由此推导监测范围内污染物总量模式。利用丹东市环境空气SO2被动扩散网格监测数据,采用此模式计算其趋势值和均值。     

上海市虹口区环境监测站质量管理的现状分析及对策探讨

通过有效运行的环境监测质量管理体系和实施监测全过程质量管理对虹口区环境监测站质量管理现状进行分析,提出了对策及建议,结果,通过建立数学分析模型对监测数据进行综合分析,实验室工作逐步做到熟练地应用测量不确定度,使环境监测站质量管理水平进一步提高,更好的为环境管理服务.     

Regional Lake Trophic Patterns in the Northeastern United States: Three Approaches

N   = 11,076). Results were compared to a large, nonrandomly sampled data set for the same area compiled by Rohm and others and contrasted with lake trophic state information published in the National Water Quality Inventory: 1994 Report to Congress [305(b) report. Lakes across the entire Northeast were identified by EMAP data as 37.9% (±8.4%) oligotrophic, 40.1% (±9.7%) mesotrophic, 12.6% (±7.9%) eutrophic, and 9.3% (±6.3%) hypereutrophic. Lakes in the ADI and NEU generally are at a low, nearly identical trophic state (96% oligotrophic/mesotrophic), while those in the CLP are much richer (45% eutrophic). EMAP results are similar to results of the Rohm data set across the entire region. In the CLP, however, EMAP identified approximately 45% of the lakes as eutrophic/hypereutrophic, while the Rohm data set identified only 21% in these categories. Across the entire Northeast, the 305(b) report identified a much higher proportion (32.2%) of lakes in eutrophic condition and a much smaller proportion (19.8%) in oligotrophic condition than did the EMAP survey data (12.5% ± 7.9% and 37.9% ± 8.5%, respectively). Probability sampling has several advantages over nonrandom sampling when regional resource condition assessment is the goal.     

湘西金矿岩温变化规律的研究及其应用

阐述了在湖南省湘西金矿对岩体温度所开展的多项试验研究工作和所取得的科研成果,特别对8中段至27中段间的岩体进行了全面的岩温测定工作,经过对测试结果的分析研究,揭示了湘西金矿岩体温度的变化规律及其对环境条件的影响,预测了深部岩体的温度。为确定合理的降温方案提供了可靠的依据,在此项成果的指导下,最终采取了以通风降温为主,再结合低温岩层预冷入风流和采用局部循环的综合降温措施,降低了工程费用,取得了较好的技术经济效果。     

浅谈重庆黑雨

重庆出现黑色降士，颜色酷似黑墨水。黑雨可燃物含量４３．８４％，ｐＨ４．０１，主要化学组分是硫酸铵，属“酸雨”和“酸化雨”。黑雨是由严重的煤烟型大气污染产生的酸度很高，对环境危害很大的大气降水。     

区域环境风险评价与风险管理及其在工程项目上的应用

论述区域环境风险评价的发展趋势，评价内容，程序和方法，探讨区域环境风险评价和风险管理的相互关系，给出岷江紫坪铺水库库区应用实例。     

一个实用的高速公路大气扩散模式

在高斯线源扩散模式的基础上，建立了一个适合高速公路大气污染源扩散特点的模式，并以沈阳环城高速公路环境影响评价中的应用为例，说明该模式的实用性和优越性．在建立该模式的过程中，应用了国外关于公路扩散试验的成果来确定和修正模式中的扩散参数．     

上海市大气中人工放射性水平调查及评价

为掌握上海市大气中人工放射性本底水平，于１９８９年９月－１９９１年１１月进行了调查。调查结果，大气气溶胶采样后１天和采样后７天的总β放射性（包括人工的和天然的）浓度分别为９．３×１０＾－２Ｂｑ／ｍ＾３和２．６×１０＾－３Ｂｑ／ｍ＾３，其中＾９０Ｓｒ浓度＜１．８×１０＾－６Ｂｑ／ｍ＾３，＾１３７Ｃｓ浓度＜１．３×１０＾－５Ｂｑ／ｍ＾３；雨水沉降物总β放射性（包括人工的和天然的）沉降率为０．７８Ｂｑ／