Distribution of perfluorinated compounds in surface water from Hanjiang River in Wuhan,China

This study provided the first spatial distribution of perfluorinated compounds (PFCs) in Hanjiang River in Wuhan, China (HR). Surface water samples, collected from 23 sites in HR were analyzed for eight PFCs. The total concentrations of PFCs ranged from 8.90 to 568 ng L⁻¹, while perfluoropentanoic acid (PFOA, <LOQ − 256 ng L⁻¹) and perfluorooctane sulfonate (PFOS, <LOQ − 88.9 ng L⁻¹) dominated. All data were found to be normally distributed in the river. Similar spatial distribution tendencies were found among perfluorocarboxylates (PFCAs) and significant correlations were observed among PFCAs, while no significant correlations were found between PFOS and PFCAs. The distributions of PFCs were highly influenced by the industrial discharge and urban activities. The flux of PFCs from HR to the Yangtze River was estimated in the range of 16.9–127 kg yr⁻¹. More than a half of the samples studied could not meet the drinking water standards and avian wildlife values, suggesting further studies of characterizing PFCs and their potential risk to human were needed.     

长沙城市景观破碎化空间异质性研究

景观破碎化表现为景观由单一、均质、连续趋于复杂、异化离散状态.空间异质性是空间景观格局产生的原因.不同尺度下景观破碎化空间异质性表现为不同的特征.遵循"尺度——格局——过程"的思路,以长沙市2005年、2010年遥感影像为数据源,针对都市区空间异质性对不同粒度和幅度水平的响应得到合适的分析尺度,进而对长沙市景观破碎化的空间格局和空间异质性展开研究,最后剖析了景观破碎化与城市生态系统的耦合过程.研究表明:(1)长沙都市区研究中,60 m粒度是一个本征观测尺度,1200 m幅度是理想特征尺度;(2)都市区景观破碎化空间格局复杂;(3)景观破碎化空间异质性受人为因素干扰影响大,随经济社会发展呈正相关关系.     

铅锌矿区农田土壤重金属的统计分析及空间分布研究

对广西某铅锌矿区周边农田表层进行了采样分析,测定了土壤中Zn、Pb、Cd、Hg、Cu、As、Ni、Cr的含量,依据土壤环境质量标准,分析了研究区域内表层土壤重金属污染程度,并通过主要成分分析和半变异函数分析,对重金属的空间分布特征进行了研究.结果表明,调查区域不同程度地受到Zn、Pb、Cd、Hg.Cu.As、Ni、Cr的污染.其中污染最重的是Cd,100%超标,超标倍数在0.67～311.93之间;其次是Zn、Hg、Pb,超标率分别为97%、84%、36%,平均超标倍数分别为10.94、3.03、1.09;污染较轻的是As、Ni、Cu、Cr.主成分分析结果将8种重金属元素分为第一主成分(Zn、Pb、Cd、Hg)和第二主成分(As、Ni、Cu、Cr),第一和第二主成分的贡献率分别为54.36%和31.19%.第一主成分在离矿区较近的西北偏西面有着较高的分布,说明第一主成分主要受铅锌矿厂污染的影响;而第二主成分在离矿区较近的西北偏西面和离矿区较远的东南偏南面都有着较高的分布,说明第二主成分不仅与铅锌矿厂的污染有关,而且与土壤母质也有很大的关系.     

惠州市城区NO2污染水平的分析与模拟

分析了2004年惠州市城区各监测站点的NO2数据,结果表明,NO2对城区空气质量影响不大。采用了城市空气质量管理软件模拟了NO2空间分布及日变化情况,且与实测值的比较分析表明,模拟结果在城区内有可比性。但地处城市边缘地带的污染模拟受光化学和区域性污染的影响,有待于进一步研究。所得结论可为惠州市城区优化布点的研究提供一定的参考。     

基于SDSS的水环境决策系统技术研究

空间决策支持系统(SDSS)作为地理信息系统与决策支持系统的结合体,兼有两者优点。文章将空间决策支持技术引入水环境计算中,讨论如何将水环境预测模型、决策分析方法与空间分析技术进行有机的结合,分析水环境空间决策模型的结构和建立过程,并结合应用实例——突发性水污染事故应急系统为例,阐明了其应用模型的特点,最后给出了相应的建设性结果。     

我国县域尺度生态环境质量状况及空间格局分析

利用全国31个省(自治区、直辖市)2008年的县域数据,按照《生态环境状况评价技术规范(试行)》(HJ/T192-2006)的方法和指标,评价了全国县域尺度的生态环境质量状况,分析县域生态环境质量的空间分布格局。结果表明,我国县域生态环境质量以"良"和"一般"为主,占国土面积的72%;东部地区县域生态环境质量好于中西部地区,中部地区县域生态环境质量以"良"为主,西部地区则以"一般"为主;在空间分布格局上,各生态环境质量类型受气候、大的地形地貌影响明显,与重要的气候分界线、山脉分布具有很好的相关性。     

济南市夏季甲醛时空分布特征及对臭氧污染的影响

基于Sentinel-5P卫星遥感数据,分析济南市2019—2021年夏季甲醛浓度的时空分布特征及对臭氧污染的影响。结果表明：研究期间夏季甲醛平均柱浓度呈逐年下降趋势,2020年同比降幅最大为24%;甲醛浓度高值区域主要分布在人口密集的市区及工业聚集的章丘区、济阳区和商河县,呈现由城市中心向外扩散的趋势;甲醛浓度受周边城市的影响,形成一条东西向的区域化污染带;甲醛对臭氧的影响主要表现在臭氧污染轻度或污染初期,而氮氧化物的排放进一步加重臭氧污染。     

Influence of urban spatial and socioeconomic parameters on PM2.5 at subdistrict level: A land use regression study in Shenzhen, China

The intraurban distribution of PM_2.5 concentration is influenced by various spatial, socioeconomic, and meteorological parameters. This study investigated the influence of 37 parameters on monthly average PM_2.5 concentration at the subdistrict level with Pearson correlation analysis and land-use regression (LUR) using data from a subdistrict-level air pollution monitoring network in Shenzhen, China. Performance of LUR models is evaluated with leave-one-out-cross-validation (LOOCV) and holdout cross-validation (holdout CV). Pearson correlation analysis revealed that Normalized Difference Built-up Index, artificial land fraction, land surface temperature, and point-of-interest (POI) numbers of factories and industrial parks are significantly positively correlated with monthly average PM_2.5 concentrations, while Normalized Difference Vegetation Index and Green View Factor show significant negative correlations. For the sparse national stations, robust LUR modelling may rely on a priori assumptions in direction of influence during the predictor selection process. The month-by-month spatial regression shows that RF models for both national stations and all stations show significantly inflated mean values of R² compared with cross-validation results. For MLR models, inflation of both R² and R²_CV was detected when using only national stations and may indicate the restricted ability to predict spatial distribution of PM_2.5 levels. Inflated within-sample R² also exist in the spatiotemporal LUR models developed with only national stations, although not as significant as spatial LUR models. Our results suggest that a denser subdistrict level air pollutant monitoring network may improve the accuracy and robustness in intraurban spatial/spatiotemporal prediction of PM_2.5 concentrations.