影响城市大气质量的主要因素分析

本文利用灰色系统的关联分析方法对影响城市大气质量的主要因素进行分析,结果发现．燃料的消耗量是影响深圳大气环境质量的主要因素,机动车辆的增长是次主要因素,工业总产值的变化对城市大气质量影响极弱,而城市的发展对大气质量均有影响,对大气中ＮＯｘ和降尘的影响最明显。     

Characterization of binding site heterogeneity for copper within dissolved organic matter fractions using two-dimensional correlation fluorescence spectroscopy

The heterogeneity of copper binding characteristics for dissolved organic matter (DOM) fractions was investigated based on the fluorescence quenching of the synchronous fluorescence spectra upon the addition of copper and two-dimensional correlation spectroscopy (2D-COS). Hydrophobic acid (HoA) and hydrophilic (Hi) fractions of two different DOM (algal and leaf litter DOM) were used for this study. For both DOM, fluorescence quenching occurred at a wider range of wavelengths for the HoA fractions compared to the Hi fractions. The combined information of the synchronous and asynchronous maps derived from 2D-COS provided a clear picture of the heterogeneous distribution of the copper binding sites within each DOM fraction, which was not readily recognized by a simple comparison of the changes in the synchronous fluorescence spectra upon the addition of copper. For the algal DOM, higher stability constants were exhibited for the HoA versus the Hi fractions. The logarithms of the stability constants ranged from 4.8 to 6.1 and from 4.5 to 5.0 for the HoA and the Hi fractions of the algal DOM, respectively, depending on the associated wavelength and the fitted models. In contrast, no distinctive difference in the binding characteristics was found between the two fractions of the leaf litter DOM. This suggests that influences of the structural and chemical properties of DOM on copper binding may differ for DOM from different sources. The relative difference of the calculated stability constants within the DOM fractions were consistent with the sequential orders interpreted from the asynchronous 2D-COS. It is expected that 2D-COS will be widely applied to other DOM studies requiring detailed information on the heterogeneous nature and subsequent effects under a range of environmental conditions.     

池塘养殖水体pH、营养盐、叶绿素a及3种磺胺类抗生素分布特征及其相关性分析

为了解农村池塘养殖水体的水质情况,分析了湖北宜东平原34个农村分散养殖鱼塘水体中pH、叶绿素a、总氮(TN)、总磷(TP)及3种磺胺类抗生素(SAs,即磺胺二甲嘧啶、磺胺甲噁唑及磺胺异噁唑),并讨论了它们之间的相关性.结果表明,所监测鱼塘水体pH值差异较小,范围为7.26~8.96,但鱼塘之间的TN、TP及叶绿素a含量差别大,其含量范围分别为0.074~47.185 mg/L、0.007~1.311 mg/L及4~421 μg/L.其中有85.29%的鱼塘水体TN含量劣于地表水V类标准,17.65%TP劣于V类,只有3个鱼塘的叶绿素a含量小于10 μg/L,水体富营养化严重.鱼塘水中3种SAs的浓度范围为23~828 ng/L,其检出率顺序为磺胺异噁唑(47%)> 磺胺甲噁唑(18%)> 磺胺二甲嘧啶(6%).对所考察因子的相关性研究表明,鱼塘养殖水体的pH、TN及TP无相关,但磺胺二甲嘧啶与TN/TP呈显著正相关(r=0.345,P=0.05).叶绿素a与水体中TN及TP的关系呈较好的幂指数函数关系,而且TP为浮游植物的生长限制因子.     

天津地区环境监测点PM2.5量化分析模型

为了研究天津地区PM2.5与5种日常监测的污染物——PM10、SO2、CO、O3和NO2的定量关系,通过天津环保物联网获取了11个环境监测点2013年8月—2014年5月的日监测数据,分别尝试了多元一次回归模型、二次回归模型和基于主成分分析回归模型进行建模与量化分析。相关性上,天津地区各站点PM2.5与5种污染物显著相关,其中与PM10、SO2和NO2相关系数分别达到0.89±0.03、0.63±0.09和0.69±0.06。模型评价结果表明,利用5种污染物监测指标预估PM2.5浓度基本可行,基于主成分分析模型效果最好,拟合度能够达到0.85以上,平均误差在20%左右。     

First report on development of quantitative interspecies structure-carcinogenicity relationship models and exploring discriminatory features for rodent carcinogenicity of diverse organic chemicals using OECD guidelines

Different regulatory agencies in food and drug administration and environmental protection worldwide are employing quantitative structure-activity relationship (QSAR) models to fill the data gaps related with properties of chemicals affecting the environment and human health. Carcinogenicity is a toxicity endpoint of major concern in recent times. Interspecies toxicity correlations may provide a tool for estimating sensitivity towards toxic chemical exposure with known levels of uncertainty for a diversity of wildlife species. In this background, we have developed quantitative interspecies structure-carcinogenicity correlation models for rat and mouse [rodent species according to the Organization for Economic Cooperation and Development (OECD) guidelines] based on the carcinogenic potential of 166 organic chemicals with wide diversity of molecular structures, spanning a large number of chemical classes and biological mechanisms. All the developed models have been assessed according to the OECD principles for the validation of QSAR models. Consensus predictions for carcinogenicity of the individual compounds are presented here for any one species when the data for the other species are available. Informative illustrations of the contributing structural fragments of chemicals which are responsible for specific carcinogenicity endpoints are identified by the developed models. The models have also been used to predict mouse carcinogenicities of 247 organic chemicals (for which rat carcinogenicities are present) and rat carcinogenicities of 150 chemicals (for which mouse carcinogenicities are present). Discriminatory features for rat and mouse carcinogenicity values have also been explored.     

基于数量关系研究铝合金船体点蚀对拉伸性能的影响

目的 通过点蚀与拉伸性能的数量关系,为5083铝合金船体不同腐蚀状态板材相应修换要求的提出提供数据支持.方法 对服役10 a的某型艇船体5083铝合金板,进行点蚀特征参数统计,并测试其拉伸性能.对四个点蚀参数与拉伸强度损失的关系进行拟合回归分析及相关性分析,找出相应的数量关系.结果 由拟合回归分析可知,最大点蚀深度数据样本与拟合曲线较契合,与拉伸性能的相关度最高.另外得出了点蚀参数与拉伸强度损失之间的函数关系,可以估计相应的指标.由相关性分析可知,最大点蚀深度与拉伸强度的相关系数大于0.9,属于强相关.自变量中,最大点蚀深度和平均点蚀深度这两个指标出现一定程度的冗余.结论 点蚀特征及拉伸性能数量关系的研究可以为铝合金船体板的拉伸性能进行相关预测,并可为铝合金船体板的耐蚀寿命研究提供依据.     

牡丹江市大气中PM10、PM2.5的污染特征及相关性研究

牡丹江市位于黑龙江省的东南部,是整个东北地区重要的区域中心城市和黑龙江省的重要开放门户.近年来,随着社会经济的发展所带来的污染及公众对环境问题的日益关注,大气环境治理工作已经迫在眉睫.通过采用颗粒物自动监测仪对2016年牡丹江市代表性的环境空气监测点位监测数据分析,研究牡丹江市区全年和各个季度PM10和PM2.5浓度的趋势变化等,得出牡丹江市区大气中PM10、PM2.5的浓度水平、季节变化特征和相关性关系以及大气污染治理方向的建议,从而为有效的空气污染控制和治理提供可靠的科学依据和技术支持.     

基于BP神经网络的城市生活垃圾产生量预测研究——以上海市为例

文章总结分析了影响城市生活垃圾产生量的因素,并根据相关性分析结果确定了主要影响因素,然后建立了上海市生活垃圾产生量的BP神经网络预测模型,并将预测值与实际值进行比较,表明该模型具有较好的适用性和准确性,最后对上海市未来几年的生活垃圾产量进行了预测.     

湘江子流域重点污染企业影响区土壤重金属镉污染源识别

土壤重金属Cd（镉）是威胁人类健康最严重的重金属污染元素之一.土壤Cd污染来源复杂,明确土壤重金属分布特征,探索重点污染企业影响区土壤重金属源解析方法,对土壤Cd污染防治具有重要意义.2018年5-9月,以湘江流域头山、大河滩两个子流域为研究对象,采用系统布点法,借助2 km×2 km的网格在研究区内均匀布点共计2 638个,分析重点污染企业对土壤Cd污染的影响及w（Cd）的空间分布特征,并借助双变量局部莫兰指数方法（bivariate local Moran's I）、广义加性模型（GAM）量化土壤中w（Cd）与企业分布的空间相关性及不同行业源的贡献率.结果表明:①研究区土壤中w（Cd）为0.032~14.01 mg/kg,平均值（0.63 mg/kg）较高,高值区主要分布在研究区西部,低值区位于研究区东部.②研究区重点污染企业总体聚集程度不高（Moran's I=0.45）,而分行业企业呈显著的高聚集分布（0.88 ≤ Moran's I ≤ 0.97）特征,尤其是冶炼与压延加工业的集聚性最为明显.③土壤中w（Cd）与不同行业的空间相关聚类分析发现,存在较大区域的H-H[土壤w（Cd）高值与企业高密度]聚类分布,说明土壤中w（Cd）受企业分布的影响较大,在企业集聚区存在较多的土壤w（Cd）高值区.④在企业影响区内,土壤w（Cd）分布受行业影响排序依次为采选业>化学品制造业>冶炼和压延加工业>其他行业,其方差解释率分别为51.2%、48.0%、46.2%、19.3%.研究显示,研究区土壤中w（Cd）分布受企业的影响明显,在污染源识别中采选业对土壤Cd污染影响最突出,研究结果可为湘江流域土壤重金属污染防治和企业污染源的管理提供依据.      

不同植被类型及土壤对径流水化学特征的影响

在不同植被类型覆盖条件下,对降雨形成地表径流和地下径流的化学成分变化及其与土壤剖面性质的关系进行分析,结果表明:地表径流和地下径流的化学特征与雨水基本相同,阳离子主要以Ca²⁺为主,离子排序为Ca²⁺>K⁺>Na⁺>Mg²⁺>NH₄⁺,阴离子以SO₄^2-为主,SO₄^2->NO₃^->Cl^-.降雨形成地表径流和地下径流后,各成分浓度发生了明显的变化,水体中主要的阴阳离子如Ca²⁺、Mg²⁺、K⁺、Na⁺、SO₄^2-、Cl^-等浓度增加,与雨水相比为内贮型化学成分,地下径流中Ca²⁺、Mg²⁺、SO₄^2-和Cl^-增加的幅度显著高于地表径流.相关分析结果显示,地下径流pH受到土壤pH的强烈影响,受土壤胶体吸附的影响,水体中Ca²⁺、Mg²⁺、K⁺、Na⁺等阳离子与土壤交换性阳离子之间一般呈负相关的关系,由于阴离子容易随水流失,水体中SO₄^2-、NO₃^-和Cl^-与土壤相关离子之间普遍呈正相关关系.