Spatial variability of organochlorine pesticides （DDTs and HCHs） in surface soils from the alluvial region of Beijing, China

The spatial variability in the concentrations of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane (DDT) in surface soils was studied on the basis of the analysis of 131 soil samples collected from the surface layer (0-20 cm depth) of the alluvial region of Beijing, China. The concentrations of total HCHs (including α-, β-, γ-, and δ-isomers) and total DDTs (i ncluding p,p'-DDT, p,p'-DDD, p,p'-DDE, and o,p'-DDT) in the surface soils tested were in the range from nondetectable to 31.72 μg/kg dry soil, with a mean value of 0.91, and from nondetectable to 5910.83 μg/kg dry soil, with a mean value of 32.13,respectively. It was observed that concentrations of HCHs in all soil samples and concentrations of DDTs in 112 soil samples were much lower than the first grade (50 μg/kg) permitted in "Environment quality standard for soils in China (GB15618-1995)". This suggests that the pollution due to organochlorine pesticides was generally not significant in the farmland soils in the Beijing alluvial region. In this study, the spatial distribution and trend of HCHs and DDTs were analyzed using Geostatistical Analyst and GS (513).Spatial distribution indicated how these pesticides had been applied in the past. Trend analysis showed that the concentrations of HCHs,DDTs, and their related metabolites followed an obvious distribution trend in the surface soils from the alluvial region of Beijing.     

Characterizing ionic species in PM2:5 and PM10 in four Pearl River Delta cities, South China

PM_(2.5)and PM_(10)samples were collected at four major cities in the Pearl River Delta(PRD),South China,during winter and summer in 2002.Six water-soluble ions,Na~ ,NH_4~ ,K~ ,Cl~-,NO_3~- and SO_4~(2-)were measured using ion chromatography.On average,ionic species accounted for 53.3% and 40.5% for PM_(2.5)and PM_(10),respectively in winter and 39.4% and 35.2%,respectively in summer. Secondary ions such as sulfate,nitrate and ammonium accounted for the major part of the total ionic species.Sulfate was the most abundant species followed by nitrate.Overall,a regional pollution tendency was shown that there were higher concentrations of sulfate, nitrate and ammonium in Guangzhou City than those in the other PRD cities.Significant seasonal variations were also observed with higher levels of species in winter but lower in summer.The Asian monsoon system was favorable for removal and diffusion of air pollutants in PRD in summer while highly loading of local industrial emissions tended to deteriorate the air quality as well.NO_3~-/SO_4~(2-) ratio indicated that mobile sources have considerably contribution to the urban aerosol,and stationary sources should not be neglected. Besides the primary emissions,complex atmospheric reactions under favorable weather conditions should be paid more attention for the control of primary emission in the PRD region.     

基于STIRPAT模型的能源消费碳足迹变化及影响因素——以江苏省苏锡常地区为例

定量研究经济社会发展对地区能源消费碳足迹的影响对区域实现低碳发展具有重要意义。论文计算了江苏省苏锡常地区1991-2008年能源消费碳足迹,采用岭回归函数对STIRPAT模型进行了拟合,采用脱钩指数分析了经济发展与能源消费碳足迹之间的关系。结果表明:①1991-2008年能源消费碳足迹平均增长速度为15.30%,能源消费碳足迹分配率以煤炭为主,石油所占比例呈波动下降趋势,天然气所占比例上升较快,能源消费碳足迹产值总体呈波动下降趋势;②经济增长是能源消费碳足迹的主要影响因素,两者关系模型拟合未出现环境库兹涅茨曲线;③经济增长与能源消费碳足迹之间处于相对脱钩与复钩的波动状态,从另一侧面验证了目前两者之间不存在库兹涅茨曲线假说的结论。     

Compositions and sources of organic acids in fine particles (PM2.5) over the Pearl River Delta region, south China

Organic acids as important constituents of organic aerosols not only influence the aerosols' hygroscopic property, but also enhance the formation of new particles and secondary organic aerosols. This study reported organic acids including C14–C32fatty acids, C4–C9dicarboxylic acids and aromatic acids in PM2.5collected during winter 2009 at six typical urban, suburban and rural sites in the Pearl River Delta region. Averaged concentrations of C14–C32fatty acids, aromatic acids and C4– C9 dicarboxylic acids were 157, 72.5 and 50.7 ng/m3, respectively. They totally accounted for 1.7% of measured organic carbon. C20–C32fatty acids mainly deriving from higher plant wax showed the highest concentration at the upwind rural site with more vegetation around, while C14–C18fatty acids were more abundant at urban and suburban sites, and dicarboxylic acids and aromatic acids except 1,4-phthalic acid peaked at the downwind rural site. Succinic and azelaic acid were the most abundant among C4–C9dicarboxylic acids, and 1,2-phthalic and 1,4-phthalic acid were dominant aromatic acids. Dicarboxylic acids and aromatic acids exhibited significant mutual correlations except for 1,4-phthalic acid, which was probably primarily emitted from combustion of solid wastes containing polyethylene terephthalate plastics. Spatial patterns and correlations with typical source tracers suggested that C14–C32fatty acids were mainly primary while dicarboxylic and aromatic acids were largely secondary. Principal component analysis resolved six sources including biomass burning, natural higher plant wax, two mixed anthropogenic and two secondary sources; further multiple linear regression revealed their contributions to individual organic acids. It turned out that more than 70% of C14–C18fatty acids were attributed to anthropogenic sources, about 50%–85% of the C20–C32fatty acids were attributed to natural sources, 80%–95% of dicarboxylic acids and 1,2-phthalic acid were secondary in contrast with that 81% of 1,4-phthalic acid was primary.     

京津冀及周边地区低碳经济发展水平评价

随着应对全球气候变化进程的不断推进,“低碳经济”已逐渐成为世界各国实现经济社会可持续发展的必由之路.京津冀及周边地区社会经济发展较不平衡,整体推进低碳经济发展存在较大的困难,为有效促进低碳经济发展的策略选择,本文通过构建低碳经济发展水平评价指标体系,对京津冀及周边地区的低碳经济发展状况进行评价.结果显示,京津冀及周边地区低碳经济发展水平差异较大：北京低碳经济水平相对较高,其他地区距离低碳经济发展水平尚有较大差距.由此,京津冀及周边地区应根据地区经济发展特点及其低碳经济发展状况,采取不同的低碳发展策略选择,以有效推进低碳经济发展模式的顺利转型.     

2000年1月15日姚安6.5级地震余震序列震源机制解与震源区应力场分析

本文利用垂直向的Pg和Sg波的最大振幅比方法,计算2000年1月15日云南姚安6.5级地震后余震序列震源机制解,通过统计和系统聚类分析,再结合震中分布图,综合分析了云南姚安6.5级地震的震源机制解和震源区应力场破裂特征,研究结果表明震源断层的走向为SEE-NWW占主导,其平均解为120°,震区主压应力轴平均解为145°,即SSE向,与震源区现今构造应力场主压应力方向一致,表明余震的应力场主要受区域应力场的控制.     

国内建设项目环境监理的发展态势、存在问题与对策一对西藏自治区开展环境监理的认识与思考

当前,我国的建设项目环境监理仍处于起步阶段。环境监理管理体系尚不完备。对西藏自治区而言,建设项目环境监理工作在许多行业领域尚属空白,法律法规仍不健全。本文通过介绍国内环境监理的发展态势及各省建设项目环境监理试点工作的经验。结合西藏自治区生态环境特征,借鉴青藏铁路环境监理试点工程取得的宝贵经验,对西藏自治区环境监理工作的开展进行探讨,以期为相关部门制定决策提供参照,尽快摸索出一条适合西藏自治区的环境监理模式,逐步使建设项目环境监理制度化,并在西藏自治区范围内成功实施。     

2012年春季京津冀地区一次沙尘暴天气过程中颗粒物的污染特征分析

本研究表征了2012年春季一次沙尘暴天气过程中京津冀地区大气可吸入颗粒物(PM10)的污染特征.借助PM10的水溶性元素、有机碳和元素碳的浓度,分析推断沙尘暴天气过程中矿物气溶胶对城市气溶胶污染的交汇叠加作用.使用中流量大气颗粒物采样器,于2012年4月1日～5月24日,在北京市西三环、天津空港经济区和张家口火车南站附近同时采集可吸入颗粒物(PM10),采用离子色谱和元素碳/有机碳分析仪分析获取其水溶性离子、元素碳和有机碳浓度.结果表明,采样期间北京、天津和张家口这3个采样点PM10质量浓度的日均值分别为233.82、279.64和238.13μg·m-3.4月27～29日,3个地区发生了沙尘暴天气,PM10质量浓度的最大日均值分别达755.54、831.32、582.82μg·m-3.沙尘暴期PM10的有机碳(OC)浓度、二次有机碳(SOC)/OC的比值、硝酸根(NO-3)和硫酸根(SO2-4)浓度均高于非沙尘暴期间.采用电荷平衡计算证明沙尘暴期间大气颗粒物表明呈碱性,说明外来沙尘暴与本地污染相互叠加,矿物元素改变了颗粒物表面的酸碱性,沙尘暴和有机物发生耦合,促进了二次有机物的转化.     

利用FLEXPART模式反演中国区域SF6排放量

六氟化硫(SF_6)是一种长寿命卤代温室气体,被列为《京都议定书》限排物种.随着经济高速发展,中国的SF6排放量受到世界各国的关注.采用传统的"自下而上"清单方法估算SF6排放量时,所需排放因子、活动水平数据的准确性和时效性存在较大局限.因此,本文利用拉格朗日粒子扩散模式FLEXPART,结合2009年北京上甸子区域大气本底站SF6浓度观测资料,尝试建立中国区域SF6排放量的反演方法.结果表明,初步反演的2009年中国区域SF6排放量为1.25×103(0.53×103~1.97×103)t·a-1,与文献结果相当,源排放量的不确定性从1.05×103t·a-1减小到0.72×103t·a-1.与先验源相比,反演源的相关系数从0.37提高到0.43,均方根误差减小了2.64%.     

京津冀地区主要排放源减排对PM2.5污染改善贡献评估

研究选取2012年1月和7月作为冬夏两季代表时段,利用CMAQ/2D-VBS模型分析了冬夏两季京津冀地区主要排放源减排30%对改善区域PM_(2.5)污染的效果.结果表明,工业源对PM_(2.5)污染的贡献最大,其次是民用源,但工业源单位减排量贡献低于民用源,交通源和电厂源的整体贡献和单位减排量贡献均较小.工业部门内贡献最大的为钢铁冶金行业,其次是水泥、工业锅炉、炼焦、石灰砖瓦和化工行业.与各部门各物种排放量的比较反映出各排放源贡献大小与其一次PM_(2.5)排放水平高度相关.因京津冀地区冬季NO_x减排对PM_(2.5)形成的促进作用,以及冬季较弱的大气垂直扩散作用,各排放源夏季减排比冬季普遍更有效,交通源、电厂源以及工业源中的水泥、工业锅炉和石灰砖瓦行业夏季减排效果相比冬季优势明显.民用源由于采暖季排放较高而冬季贡献更明显,农业源因秸秆开放燃烧量大,冬季单位减排量贡献十分显著.从同等幅度减排考虑,应将工业源作为控制重点,优先控制其一次PM_(2.5)排放,在部门内进一步重点控制钢铁冶金行业的NO_x和SO_2排放、水泥行业的夏季NO_x排放以及炼焦行业的SO_2和NMVOC排放.民用源排放应着重在冬季采暖期控制.