黄河甘宁蒙段重金属及其生态风险研究

黄河是中国西北地区最重要的水源,为了研究黄河上游甘宁蒙段水体的重金属含量及其潜在生态风险,本文分别使用AFS和HR-ICP-MS对黄河甘宁蒙段12个采样点过滤水和悬浮物中As,Hg,Cd,Pb,Cr,Ni,Cu 和 Zn等重金属元素的含量进行了测定。结果表明：各采样点过滤水中,除Cr (56.9~71.5 μg·L-1)外,其他重金属元素的含量均低于饮用水水质标准限值。TN,TP和 pH等水质参数的测定结果显示,除 S1 (2.48) 和 S9 (2.38)采样点的TN超过国家地表水环境质量标准第Ⅴ类标准外,其他各采样点参数值均较低。悬浮物中,Hg,Cd,Pb 和Zn的含量均高于各采样点所在地区相应元素土壤背景值。聚类分析结果显示Ni,Cu,Cr,Zn和Pb有相同污染来源,主要来源于不锈钢产业和石油产业;As,Cd和Hg三种重金属元素的来源各不相同,主要可能来自于农药,化肥,采矿和燃料以及煤的燃烧。应用RI和Er对各采样点以及单个重金属元素的潜在生态风险进行了评价。结果显示,除S1采样点为中度生态风险外,其他采样点均为显著生态风险(300.6 < RI < 508.6),Er指数显示Hg在内蒙段为显著-高生态风险,Cd在S11 (396.0), S9 (384.0) 和 S5 (373.3)采样点为极高风险,说明Hg和Cd在这些采样点污染较为严重。以上研究结果可以为相关部门提供可靠的实验数据和理论依据。     

Dissolved Oxygen Concentration Prediction Model Based on WT-MIC-GRU—A Case Study in Dish-Shaped Lakes of Poyang Lake

Dissolved oxygen concentration has the characteristics of nonlinearity, time series and instability, which increase the difficulty of accurate prediction. In order to accurately predict the dissolved oxygen concentration in the dish-shaped lakes in Poyang Lake of Jiangxi Province, China, a dissolved oxygen concentration prediction model, based on wavelet transform (WT)-based denoising, maximal information coefficient (MIC)-based feature selection, and the gated recurrent unit (GRU), was proposed for this study. In experiments, the proposed model showed good prediction performance, achieving a root-mean-square error (RMSE) of 0.087 mg/L, a mean absolute percentage error (MAPE) of 0.723%, and a coefficient of determination (R2) as high as 0.998. It shows that the prediction model based on the combination of the wavelet transform and the GRU has a relatively high prediction accuracy and a better fitting effect. The model proposed in this study can provide a reference for protecting this type of lake-water body and the restoration of missing values in lake water quality monitoring data.     

Modeling Overdispersed Dengue Data via Poisson Inverse Gaussian Regression Model: A Case Study in the City of Campo Grande,MS, Brazil

Dengue fever is a tropical disease transmitted mainly by the female Aedes aegypti mosquito that affects millions of people every year. As there is still no safe and effective vaccine, currently the best way to prevent the disease is to control the proliferation of the transmitting mosquito. Since the proliferation and life cycle of the mosquito depend on environmental variables such as temperature and water availability, among others, statistical models are needed to understand the existing relationships between environmental variables and the recorded number of dengue cases and predict the number of cases for some future time interval. This prediction is of paramount importance for the establishment of control policies. In general, dengue-fever datasets contain the number of cases recorded periodically (in days, weeks, months or years). Since many dengue-fever datasets tend to be of the overdispersed, long-tail type, some common models like the Poisson regression model or negative binomial regression model are not adequate to model it. For this reason, in this paper we propose modeling a dengue-fever dataset by using a Poisson-inverse-Gaussian regression model. The main advantage of this model is that it adequately models overdispersed long-tailed data because it has a wider skewness range than the negative binomial distribution. We illustrate the application of this model in a real dataset and compare its performance to that of a negative binomial regression model.     

黄浦江上游遥感监测溶解氧模型与时空变化

溶解氧含量是反映水体有机污染的重要水质指标。文章选择黄浦江上游水源中的典型水质参数——溶解氧为研究对象,利用地面高光谱遥感数据、多光谱遥感数据和现场水质监测数据来研究水体反射光谱特征与水质参数浓度之间的关系,发现溶解氧含量与641 nm波段的光谱反射率相关性最高,由Landsat5 TM第3和4波段的遥感反射率比值变量所建立的对数模型相关性最高,达到0.829。在此基础上,基于多时相遥感影像对溶解氧模型的通用性和准确性进行验证,并探讨了溶解氧的时空变化规律。结果表明,该模型具有较高精度,估测值与地面实测值在时间变化规律上保持一致,同时根据该模型得出的黄浦江上游溶解氧含量空间分布规律与该区域的有机污染实际分布情况是相互吻合的。     

Prediction and Limitations of Noise Maps Developed for Heterogeneous Urban Road Traffic Condition: A Case Study of Surat City,India

Road traffic noise pollution has been recognized as a serious issue which affects human health as well as affects urban regions. Noise maps are very beneficial to identify the impact of noise pollution. A noise mapping study performed to study the propagation of noise in tier-II city along with field measurements. The noise maps are developed using a computer simulation model (SoundPLAN essential 4.0 software). The noise prediction models like U.K’s CoRTN, Germany’s RLS-90, and their modified versions, which can be used for homogenous road traffic conditions, cannot be successfully applied in heterogeneous road traffic conditions of India. In developing country like India, road traffic noise pollution depends on the composition of heterogeneous traffic volume, variance in road geometrical, honking conditions, un-authorized parking, and varying density of the building on either side of the road. These traffic compositions contain vehicles, which have different sizes, speeds variations, a different dimension of vehicles. Because of fluctuating speeds, lack of lane disciplines, and un-authorized parking on main road lanes, honking events becomes inevitable, which changes and affects the urban soundscape of nations like India. Analysis of noise maps showed that horn honking due to un-authorized parked vehicles contributed an additional increase up to 11 dB (A) noise, which is quite significant.     

HR-ICP-MS研究丰水期黄河甘宁蒙段表层沉积物中重金属的形态分析与污染评价

为连续、系统地研究不同年份丰水期黄河甘宁蒙段表层沉积物中重金属的含量、污染状况和潜在生态风险,在前期工作的基础上,采用三级四步提取法(BCR)和高分辨电感耦合等离子体质谱(HR-ICP-MS)对2012年丰水期黄河甘宁蒙段包头浮桥(S2)、石嘴山陶乐镇(S6)和乌金峡(S9)等10个采样点水体表层沉积物中Cd,Pb,Cr,Ni,Cu,V,Co,Zn和Mn九种重金属元素进行含量测定和形态分析,并对重金属元素的污染作出评价。结果表明：各重金属元素在每个采样点分布趋势相同,平均含量顺序依次为：Mn＞V＞Zn＞Cr＞Cu＞Ni＞Pb＞Co＞Cd;表层沉积物中重金属主要以残渣态形式存在,表明重金属的生物有效性低,对环境影响较小;地积累指数法 (I_geo) 的评价结果显示Cd元素的I_geo值最高,对环境污染程度较高,其余元素对环境影响较小,其中Mn元素影响最小;富集因子法(EF)评价结果表明,Cd和Cu元素在某些采样点表现为显著富集,尤其是Cd在S5点处EF值高达4.69,表明该点处Cd受人类活动影响较为明显,其余元素均为非富集元素,这与I_geo评价结果吻合;潜在生态风险指数法(RI)表明,黄河甘宁蒙段S1,S2和S5点的RI值在150~300之间,为中等危害范畴,其余各采样点RI值均小于150,为轻微危害。研究结果为相关部门提供可信的实验数据和理论依据,也为建立该河段泥沙-污染物输移数学模型和系统研究持久性有毒污染物迁移转化规律及环境评价提供技术支撑。     

HR-ICP-MS对黄河甘宁蒙段过滤水和悬浮物中稀土元素含量测定与分馏作用研究

采用高分辨电感耦合等离子质谱(HR-ICP-MS)对黄河甘肃、宁夏、内蒙古段12个采样点过滤水和悬浮物中稀土元素含量进行了测定,并对悬浮物中稀土元素的分馏作用进行了研究。结果表明：过滤水中稀土元素含量较低,含量最高的元素镧(La)浓度仅为32.0 ng·L-1,稀土元素总量平均值为47.5 ng·L-1,以包头磴口(S1)和三湖河口(S2)最高,分别为130.0和100.0 ng·L-1,可能是由外源稀土进入水体所致;悬浮物中稀土元素总量平均值为167.8 mg·kg-1,与中国土壤背景值相近,其中,甘肃什川桥采样点(S11)重稀土元素含量明显高于其他采样点,表明该采样点受到外源重稀土的影响。悬浮物中稀土元素球粒陨石标准化结果与中国土壤分布模式相同,表现为轻稀土元素富集,铕(Eu)中度亏损,铈(Ce)呈现弱的亏损,表明悬浮物中稀土元素主要来源于土壤风化作用。     

Identifying local and regional groundwater in basins: chemical and stable isotopic attributes of multivariate classification of hydrochemical data,the Lower Virgin River Basin,Nevada, Arizona and Utah,U.S.A

In the Basin and Range Province of the Southwestern U.S.A., deep carbonate groundwater has been suggested as a significant source to many overlying basin-fill alluvial aquifer systems. Notwithstanding, testing this hypothesis is limited by obtaining data from such considerable depths and complex geology.

This study uses δ²H and δ¹⁸O data from springs, rivers, and wells tapping shallow basin-fill groundwater to test the hydrochemical interpretation of deep regional carbonate groundwater flow into the basin-fill aquifers. Stable isotopic and major ion attributes of hydrochemical facies suggest basin-fill alluvial groundwater of the Lower Virgin River Basin is a mixture of precipitation recharge within the Lower Virgin River Basin or the Clover and Escalante Desert Basin northwards, and the deep carbonate flow. The data support the conclusions that in the Lower Virgin River Basin, deep carbonate groundwater is an important source to the alluvial aquifer system and likely accounts for approximately 50% of the alluvial aquifer groundwater. Na⁺, K⁺, and SO₄^2– increase in the basin-fill alluvial groundwaters outside the Virgin River floodplain appears to be related with upwelling of deep regional groundwater, and indicating that the chemical character of the basin-fill alluvial groundwaters are related to the deeper flow systems.     

基于多种光谱学分析技术的地质样品宏微观组构特征研究——以钦杭成矿带南段金山银金矿床岩石样品为例

地质过程的复杂性造就了地质样品宏观和微观特征的不均一性,这些地质样品的不均一特征可以通过光谱学分析技术予以有效的揭示。研究以钦杭成矿带南段金山银金矿床的矿石与围岩样品为例,开展了基于X射线荧光光谱(XRF)和等离子体质谱(ICP-MS)分析技术的宏观地球化学特征和基于拉曼光谱(Raman)分析的微区特征分析。宏观地球化学分析结果表明,矿石与围岩的主量元素组成差别较大,但稀土元素配分模式和微量元素分布模式基本相似,这反映微量元素和稀土元素在成矿作用过程中表现出了较高的地球化学稳定性。关于石英的拉曼分析结果显示,矿石的石英存在507 cm-1附近的峰位,而围岩样品均没有出现,这应该反映了二者结晶过程中具有不同的温度和压力等条件并导致石英结构存在差异,该拉曼位移的存在与否构成了成矿过程相关地质作用的判别标志。矿石与围岩中石英463 cm-1附近拉曼位移的半高宽(FWHM)及拟合峰积分强度比对结果显示,矿石样品中石英结晶程度与有序度明显优于围岩样品中石英,这反映了成矿过程中热液活动对石英微观结构的改造。围岩中石英受后期热液影响大,部分成矿物质源于热液从围岩中带出,且成矿流体存在多期性,不同阶段矿物结晶程度不同,从而造成了特征拉曼位移FWHM值的不同。     

光度法对不同水期黄河甘宁蒙段表层沉积物中磷积累程度和交换能力的比较研究

磷是水体富营养化的主要控制因素,在外源磷输入逐步得到控制后,作为内源磷主要来源的表层沉积物对黄河水体水质的影响作用不容忽视。掌握表层沉积物中磷的积累程度以及沉积物-水界面磷的交换能力,对区域内水环境的治理和磷负荷的调控具有重要的意义。选择黄河甘宁蒙段作为研究区域,分别采集丰水期(2011.07)、枯水期(2014.05)和平水期(2014.10)表层沉积物样品,使用标准测试程序(SMT)和钼锑抗分光光度法测定样品中磷赋存形态,并在实验条件下模拟表层沉积物对磷的等温吸附及吸附动力学过程。研究发现：(1) 相比于国内主要河流表层沉积物中磷的形态特征,黄河甘宁蒙段表层沉积物中有机磷(OP)和铁/铝结合态磷(NaOH-P)含量相对较低,钙结合态磷(HCl-P)含量较高;各形态磷含量的平均值均在丰水期最高,表明丰水期表层沉积物中磷的积累程度最高,黄河甘宁蒙段水环境受到沿程农业发展的冲击较大。因此,合理使用含磷化肥和优化灌渠退水水质是未来降低黄河水体磷污染风险的发展方向。(2) 基于低磷浓度下等温吸附中各采样点表层沉积物吸附-解吸平衡浓度(EPC₀)与判断水体发生富营养化的磷浓度阈值的比较发现,研究区域所有水期大多数采样点表层沉积物发挥着“磷源”的作用,存在向上覆水释放磷的趋势,且枯水期中多数采样点的EPC₀值较高,“磷源”作用更加明显;基于L模型和F模型对高磷浓度下等温吸附的拟合参数,显示丰水期表层沉积物对磷的持留能力最强,枯水期次之,平水期最小,所有采样点表层沉积物对磷的吸附过程均易发生;基于吸附动力学曲线的变化趋势可知,所选择的各采样点磷吸附量在反应开始的12 h内迅速增大,12~48 h内吸附量逐渐增加并趋于稳定;基于伪二级动力学方程对吸附动力学过程的拟合结果,表明表层沉积物对磷吸附过程的反应速率受化学吸附控制为主;从同一水期不同采样点吸附过程中的限速步骤不同及不同水期邻近采样点吸附过程中限速步骤均为微孔扩散的结果发现,表层沉积物组成和理化性质的差异对磷吸附速率的影响大于不同水期条件下上覆水流速和流量的变化。