天然气开发对区域水环境安全的影响研究——以川东平原德阳地区为例

天然气开发在实际过程中大多是区域滚动开发,对流域的水环境安全可能形成较大的影响和隐患.运用主成分分析法对区域内各部分环境特征和国家环境质量标准进行分析、处理、排序,能够识别区域内各部分的环境质量变化情况,为区域环境管理和风险预防提供理论基础.以川东盆地,沱江和涪江上游德阳地区天然气区域开发为例,分析天然气开采对区域内各部分地表水环境质量的影响.可知在选定的4个水质参数中,pH值和COD两个主成分能够代表开发前所有监测信息的93.02%,开发后的95.09%.研究结果表明,在加强环境保护的前提下,区域天然气开发不会影响区域水质;同时也证明在区域水环境安全评价中主成分分析法是一种非常有效、快速的方法.     

杉木生长对南方涛动的可能响应

对杉木中心产区边缘杉木个体年轮生长规律进行了研究,分析了杉木年轮生长的特点,建立杉木个体年轮的时间模型,求算年轮指数,通过对２０多年来南方涛动指数第一、第二主分量与杉木人工林生长关系的研究,探讨南方涛动对杉木生长的可能影响,以南方涛动第一、第二主分量为自变量,建立杉木人工林年轮生长模型,模拟精度达９１．０５％,说明南方涛动对杉木人工林胸径生长可能存在一定影响（α＝０．０５）。     

神经网络在次级河流回水区叶绿素a浓度预测中的应用

以长江次级河流之一的临江河为研究对象,探讨神经网络应用于次级河流回水区叶绿素a浓度短期预测的可行性。利用主成分分析法（PCA）选取对叶绿素a浓度影响较大的指标,在这些指标数据的基础上建立RBF神经网络模型。网络训练和测试的结果表明,模型模拟精度较高,说明RBF神经网络模型可以用于次级河流回水区叶绿素a浓度的短期预测。通过对临江河回水区叶绿素a影响因子的分析,表明控制水体中磷含量应是临江河回水区富营养化防治的重点。     

Soil plate bioassay: an effective method to determine ecotoxicological risks

Levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were measured in the breast milk of mothers living in Giugliano (Campania, Italy), an area at increased risk of PCDD and PCDF exposure caused by recent and serious open-air waste-combustion accidents. Polychlorinated biphenyls (PCBs) in milk samples were also studied. Breast milk was also monitored in two cities in northern Italy, Milan and Piacenza, which were selected as controls. Other variables, such as diet and age of the mothers, were also studied. PCDD/F and PCB levels and congener profiles in breast-milk samples were similar in all these cities, though total PCDD/F and DL-PCB TEQs in samples from Giugliano were significantly lower than those in Milan and Piacenza (8.65 pg WHO-TEQ in Giugliano vs. 11.0 and 9.94 pg WHO-TEQ in Milan and Piacenza respectively). Thus no direct correlations were found between PCDD/F and PCB levels in breast milk and the suspected increased exposure through open-air waste combustion in Giugliano. Diet did not seem to affect PCDD/F and PCB levels, whereas a significant correlation was observed between the mother’s age and an increased concentration of PCDDs/Fs and PCBs in milk. Comparison of these findings with those of previous surveys in Italy in 2000-2001 showed a marked reduction of PCDD/F (about 60%) and DL-PCB (about 20%) levels in breast milk occurring over the last 10 years. This might well be a result of well functioning legislation, for example European Directives on of the reduction of the emission limits of PCDDs/Fs and PCBs from waste incineration set by EU Directive 2000/76/EC implemented in 2000, or Commission Regulations such as (EC) No. 466/2001 and 1881/2006 setting maximum levels for certain contaminants in foodstuffs.     

洞庭湖区湿地景观指数选取与格局分析

在遥感与地理信息系统的支持下,从2000年的LANDSAT TM影像中提取洞庭湖湿地信息,结合景观结构分析软件FRAGSTATS计算湿地景观指数,采用主成分分析法与方差矩阵分析法选取最能表征湿地结构及功能的核心景观指数,分析洞庭湖区湿地的景观结构特征及功能状态。研究表明：Shannon多样性指数、斑块面积标准差、斑块丰富度密度与景观类型平均分维度最能反应湿地景观的信息及特征;研究区景观格局的空间差异性与组织结构状态具有明显的不均衡性,湿地景观类型比例不均,水田与湖泊景观优势显著;以洞庭湖核心区滨湖的县市和远离湿地核心区的县市为两大群体,在景观格局复杂性和多样性状态中表现出两大群体相似的特征。     

辽宁省14市环境综合发展状况定量研究

良好的生态环境是城市健康、可持续发展的基础和前提,在环境支持能力允许范围内发展经济是世界上各城市正面临的严峻挑战。运用SPSS15.0统计软件,对辽宁省14市10项环境指标进行主成分分析,得出相关结论。从时间上看,辽宁省大部分城市10年间的环境排名变化差异较小;从空间上看,辽西城市带的环境状况较差。提出了辽宁省今后应在环境法规建立、产业转型与产品升级、环保宣传教育等方面加以注意。     

湿法烟气脱硫GGH换热元件结垢问题探讨

针对三河发电有限责任公司一期工程配套脱硫系统GGH换热元件结垢现象,分析了GGH换热元件结垢原因,提出减缓GGH结垢的措施,为相关脱硫项目运行提供参考。     

Hydrochemistry of Wet Atmospheric Precipitation Over an Urban Area in Northern Indo-Gangetic Plains

Rain water samples were collected to study the chemical composition of wet atmospheric precipitation (first event) over the Lucknow city in the northern Indo-gangetic alluvial plains. The samples were collected in the month of July, 2005 from different sites. The wet precipitation samples were analyzed for pH, EC, major ions (, Cl⁻, , , , F⁻, Na⁺, K⁺, Ca²⁺, Mg²⁺, ) and heavy metals (As, Cd, Al, Co, Cr, Cu, Fe, Mn, Mo, Ni, Hg, Pb, Se, Sn, Ti, V, Zn). The pH values of wet precipitation samples ranged between 6.5 and 8.7. The analysis of linear regression applied to the set of studied variables and computation of neutralization factors showed that neutralization occurred in precipitation samples and Ca²⁺ had the maximum neutralization capacity. It was found that Cl⁻, , Ca²⁺, Mg²⁺, Na⁺ and K⁺ in the precipitation samples originated mainly from crustal/anthropogenic sources in the region. On an average Fe, and Al accounted for >72% of the total concentration of trace metals in the wet precipitation samples followed by Zn (>10%). Enrichment factors calculated for heavy metals over reference background level in seawater and Earth’s crust showed relatively higher enrichment of Zn. The principal component analysis (PCA) identified the possible sources of ionic species and heavy metals in the wet precipitation samples.     

苏州市霾日细颗粒物的化学组分及来源分析

随着社会和经济的快速发展,灰霾现象发生有逐渐上升趋势,严重影响城市形象和群众的身心健康。2012年苏州市的霾日发生频率1—2月最高(45.0%),7—8月最低(4.8%)。通过分析霾日细颗粒物(PM2.5)的化学组分变化,有助于判别不同化学组分在不同季节霾日形成中的作用。采用基于因子分析的主成分提取方法,将9个化学组分监测资料整合为4个主成分,并逐一揭示2012年苏州市霾日条件下4个主成分的支配因子的污染物来源情况。结果表明:2012年苏州市霾日大气PM2.5中的主要化学成分按质量浓度从高到低排序依次为SO42-NO3-NH4+OCNa+EC。霾日PM2.5中的污染物组分受到光化学二次反应、燃煤、机动车尾气、农作物秸秆焚烧以及海盐等来源的综合影响。     

Statistical source identification of metals in groundwater exposed to industrial contamination

Levels of selected metals Na, Ca, Mg, K, Fe, Mn, Cr, Co, Ni, Cd, Pb and Mn were estimated by flame atomic absorption spectrophotometry in groundwater samples from Kasur, a significant industrial city of Pakistan. Salient mean concentration levels were recorded for: Na (211 mg/l), Ca (187 mg/l), Mg (122 mg/l), K (87.7 mg/l), Fe (2.57 mg/l) and Cr (2.12 mg/l). Overall, the decreasing metal concentration order was: Na > Ca > Mg > K > Fe > Cr > Zn > Co > Pb > Mn > Ni > Cd. Significantly positive correlations were found between Na–Cr (r = 0.553), Na–Mn (r = 0.543), Mg–Fe (r = 0.519), Mg–Cr (r = 0.535), Pb–K (r = 0.506) and Pb–Ni (r = 0.611). Principal Component Analysis and Cluster Analysis identified tannery effluents as the main source of metal contamination of the groundwater. The present metal data showed that Cr, Pb and Fe levels were several times higher than those recommended for water quality by WHO, US-EPA, EU and Japan. The elevated levels of Cr, recorded as 21–42 fold higher compared with the recommended quality values, were believed to originate from the tanning industry of Kasur.