汾渭平原空气质量的时空特征及其与气象因子的关系

汾渭平原是继京津冀和长三角之后环境污染治理的第三大重点区域,为发挥协同作用改善区域大气质量提供更为科学客观的依据,基于2014—2019年汾渭平原11个重点城市的空气质量监测资料和气象数据,利用统计方法分别从空间和时间尺度上揭示了汾渭平原空气质量指数以及主要污染物特征,及其与气象因子的关系.结果表明：11个城市中有7个城市的年均AQI指数100以上,重度以上天数占6%,重污染聚集区主要集中在关中中东部.从时间尺度看,AQI的年际波动明显且在2017年之后略有改善,冬春季特别是1月污染最为严重且呈现出明显的周末效应.首要污染物的季节差异较大,冬季以PM_2.5和PM₁₀为主,而夏季则主要以O₃为主,春秋季则分别以PM₁₀和PM_2.5为主.从气象影响因子看,年尺度上气压、降水、平均气温以及混合层高度除与O₃为正相关外与其它污染物均为显著的负相关,且呈现出明显的季节差异.而降水无论年尺度还是季节尺度上均对空气质量有利,特别是中雨量级以上的降水过程对颗粒物和O₃污染的改善作用明显.     

阜新市秋冬季节PM2.5中无机元素污染特征及来源

为研究阜新市秋冬交替期间大气PM_2.5无机元素污染特征及来源,于2017年10月、12月对城区4个点位采集样品,利用ICP-MS、AFS-8900、ICP-AES测定18种元素含量,结合气象参数,分析秋、冬两季PM_2.5污染特征,运用富集因子法（EF）、主成分分析法（PCA）及聚类分析法解析PM_2.5元素污染特征及来源.结果表明,阜新城区冬季PM_2.5质量浓度（56.5μg/m³）是秋季的1.5倍,秋、冬两季PM_2.5平均质量浓度为47.5μg/m³;冬季PM_2.5与SO₂、NO₂的同源性表现强于秋季;冬季PM_2.5中V、Cr、Mn、Ni、Cu、Zn、Pb、As、Cd、Hg、Mg、Ti 12种典型人为源标识性元素总质量百分比（8.78%）是秋季的1.45倍,表明城区冬季PM_2.5显著受到人为活动影响.富集因子分析显示EF值大于100的元素为Cd、Hg、Zn,冬季EF（Cd）高达532.34,可能与城南3km公里处露天矿坑大量残煤自燃排烟有关;冬季EF（Cr）比秋天增高了7.9倍.源解析结果表明,燃煤与工业烟尘、机动车尾气、生物质燃烧及土壤风沙扬尘是阜新PM_2.5无机元素的主要来源.秋季表现出明显的来源复合性,第一主因子解释了变量总方差的77.013%,聚类分析第1类包含了Cd、Hg、Mn、Ni、As、V、Cr、Cu、Pb、Zn、Ti和Mg 12种元素;冬季则表现出明显的来源广泛性,表明冬季PM_2.5来源相对复杂,应强化冬季PM_2.5污染综合防治与管控.     

Trace elements and stable sulfur isotopes in plants of acid mine drainage area: Implications for revegetation of degraded land

The abundances of trace elements, a low pH of water and soil in areas impacted by the acid mine drainage (AMD) may cause an excessive uptake of potentially toxic elements and nutritional imbalances in plants. Metal-tolerant, native plants are used for revegetation of degraded mining areas. We established levels of selected trace elements and stable sulfur isotopes in the above-ground plant biomass collected in a mining area in south-central Poland. In 2016, 20 samples of the most common species were collected from sites with a different influence of acid mine drainage and analyzed for trace elements by the inductively coupled plasma mass spectrometry technique. On the basis of the results obtained in 2016, the most contaminated site was selected for a more detailed study, in which sulfur contents and stable sulfur isotope ratios were determined together with trace elements in 17 samples. The results confirmed that the plants native to the AMD area efficiently accumulated trace elements, especially As and rare earth elements. Mosses showed the highest content of trace elements, but exhibited the lowest concentrations of sulfur accompanied by the highest δ³⁴S values. It has been shown for the first time that stable sulfur isotope composition of AMD plants in south-central Poland is significantly depleted in the ³⁴S isotope showing an average δ³⁴S value of –10.5‰ in comparison with positive δ³⁴S values in local vegetation growing outside the AMD area and in local precipitation.     

南方红壤侵蚀流域水稻田中稀土元素的迁移累积特征

稀土元素通过植物吸收经食物链最终进入人体,并在人体中累积,进而影响食用人群的健康.水稻作为我国南方地区的主要粮食和经济作物,是人们生存的基础.本文通过南方花岗岩红壤侵蚀流域水稻植株根系土壤及其各部位稀土元素含量的调查,探究稀土元素在土壤-水稻系统中的迁移累积特征.结果表明:研究区土壤中稀土元素含量平均值为389.02 mg·kg~(-1),水稻土壤中呈现出重稀土元素相对富集的特点.土壤中稀土元素在Eu处呈亏损状态;除10号样点外,其他样点土壤的稀土元素在Ce处呈富集状态.水稻植株不同部位的稀土元素含量差异较大,水稻根、叶及稻谷中稀土元素含量的平均值分别为152.63、5.03和0.64 mg·kg~(-1),呈根叶稻谷的规律.稻谷中的稀土元素含量虽未超过日均稀土元素的摄入量(5.33μg·kg~(-1)·d~(-1)),但长期食用仍存在一定的健康风险.土壤稀土元素向水稻植株各部位的转移能力差异较大,呈根叶稻谷的规律.     

不同时间尺度气象要素与空气污染关系的KZ滤波研究

空气污染状况受气象要素和污染源排放的共同影响,为了评估大气污染控制措施的效果,需将由污染源排放的浓度数据分离出来.本文利用KZ滤波方法将天津市6个监测站点2015~2017年逐日的O₃、PM_2.5和PM₁₀浓度资料和6个同期气象数据分解为长期分量、短期分量和季节分量,计算各分量对原始时间序列方差的贡献.采用逐步回归法建立O₃及颗粒物3种分量与相应尺度气象要素的线性模型.结果表明,上述3种污染物浓度数据经分解后,季节分量对总方差贡献最大,其次为短期分量;气温和相对湿度是影响O₃季节和短期分量的主要气象因素,其中温度占主导地位,且呈现正相关,与相对湿度呈负相关;风速、气压、降水与颗粒物的短期及季节浓度变化呈负相关,相对湿度与之呈正相关,温度与短期分量呈正相关、与季节分量的变化呈负相关;经逐步回归消除气象影响的PM₁₀的长期分量有波动下降的趋势,PM_2.5浓度在2017年年初有所上升,其余部分有下降趋势,O₃长期分量浓度有所上升;这几年间颗粒物污染控制措施的效果较为显著,O₃污染有所加重.     

DYNAMIC RESPONSE OF AQUIFER SYSTEMS TO LOCALIZED RECHARGE1

ABSTRACT. The response of stream-unconfined aquifer systems to localized recharge is investigated by means of a two-dimensional finite element model. A variational approach is used in conjunction with the finite element method to solve the ground water flow equation. Linear approximated triangular elements are used to calculate the hydraulic head distribution in the flow region. The Crank-Nicholson centered scheme of numerical integration is employed to approximate the time derivative in the flow equation. A computer program is developed to calculate the hydraulic head distribution in the flow region. Solutions provided by the finite element model should prove useful in the evaluation of quantitative and qualitative changes in aquifer systems due to natural or artificial recharge. In addition, they should prove useful in the study of irrigation and drainage problems.     

论环境犯罪的构成要件

文章从环境犯罪的概念入手,进一步阐释环境犯罪的构成要件。通过对四个构成要件逐个剖析,对进一步完善环境刑法提出了自己的看法。     

Modelling of the relationship betwen trace elements and three species of sulfur in coal

ＭｏｄｅｌｉｎｇｏｆｔｈｅｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｎｔｒａｃｅｅｌｅｍｅｎｔｓａｎｄｔｈｒｅｓｐｅｃｉｅｓｏｆｓｕｌｆｕｒｉｎｃｏａｌＬｕＸｉａｏｈｕａ，ＺｅｎｇＨａｎｃａｉＮａｔｉｏｎａｌＫｅｙＬａｂｏｒａｔｏｒｙｏｆＣｏａｌＣｏｍ...     

Complex behaviour of trivalent rare earth elements by humic acids

The complexation behaviours of trivalent rare earth elements (La, Ce, Ho and Yb) by two types of humic acids were investigated under a specified set of conditions. Humic acids show quite different complexation capacities an conditional formation constants with the REEs. Apparently there are two types of binding sites in the functional groups of humic acid, in which the first binding sites have stronger ability than the second. Cerium shows the largest complexation capacities and highest formation constants among the four REEs with two humic acids, this anomaly may be relative to the distribution pattern of the REEs in seawater. The experimental results were comparable to the values of other metals reported and provided the basic data for environmental geochemistry of rare earth elements.     

南京冬季一次强浓雾及超细粒子累积过程分析

课题组于2017年冬季在南京北郊开展了为期45d的雾/霾外场综合观测，并选取12月30~31日一次平流辐射雾过程，分析了气象要素、雾和气溶胶的宏微观特征.结果表明：冷平流与夜间辐射冷却造成的持续性降温为此次雾发展的主要原因，而短波辐射增强则为雾消散的主导因子；此次雾过程存在爆发性增长的特征，表现为17min内含水量的量级由10-4g/m³增加至10-1g/m³，其中雾滴数浓度的增加对其贡献率可达67%；强浓雾微物理量的时间变率波动性强，雾的水平分布存在显著的不均匀性特征；日出后的强浓雾阶段中存在纳米级气溶胶累积现象，空气动力学直径在10~50nm气溶胶的数浓度增加率可达2817cm^-3/h，从二次气溶胶生成（SO₂的气-粒及气-液转化过程）、输送（人为活动造成的气溶胶累积及雾中垂直向湍流的输送）等方面探讨现象出现的原因.