黄河内蒙古段沉积物中汞含量及形态研究

为探明黄河内蒙古段水体沉积物中的汞含量及其形态分布特征,以黄河内蒙古段干流水体柱状沉积物为研究对象,采用改进的Tessier形态逐级提取法,分级提取水溶及可交换态、碳酸盐及铁锰氧化物结合态、腐殖质结合态、难溶有机质结合态及硫化物态和残渣态5种形态汞,用氢化物发生-原子荧光分光光度法测定汞含量,结果表明:黄河内蒙古段柱状沉积物中汞含量为12.1~47.1μg/kg,平均为21.4μg/kg;从整体上看,左岸沉积物中汞含量高于右岸,从上游至下游,汞含量呈先上升后下降趋势;沉积物中汞以腐殖质结合态为主,残渣态次之;腐殖质结合态汞含量随深度增加呈明显下降趋势,其他形态汞含量随深度增加呈上升趋势。     

松花江汞与甲基汞的污染变迁

受吉化公司电石厂醋酸车间生产乙醛的影响，在20世纪60～70年代，松花江水体受到严重的汞污染，文章阐述了松花江受汞和甲基汞污染及治理的5个阶段，分析了演变过程。     

含汞废水的净化方法

汞及其化合物有很高的毒性,水体中汞的极限浓度为0.005毫克/升,因此废水在排入水体之前,必须进行深度净化。在苏联和其他国家的专利文献中,对用各种物理和化学方法净化废水中汞化合物的报道很多。其中包括: 采用硫化钠、甲叉脲、含有磷化氢的乙炔气,2,3-二巯基丙烷磺酸盐、红胺酸铝、硫代硫酸钠和二硫代苯对二酸或者采用2,3-二巯基丙烷酸和硫代硫酸盐的碱溶液,而后用无机酸、硫脲和锆的粉沫等将汞转变为不溶解的汞。采用硫化铁,例如黄铁矿,或者冶金工业矿渣吸收汞,然后在400～500℃的情况下回收金属汞。也可在具有氯气情况下,用阴离子交换剂,或者用溶解度很小的硫化铜、硫化锌、硫化铅、硫化镍、     

硫化钠助剂混凝法去除饮用水中微量汞的实验研究

我国不少河水受到汞的污染。汞进入水体后,常积存于河流的底泥中,成为河水的长期污染源。迄今,对水中微量汞的去除,尚缺乏经济易行的处理方法。本文提出的方法可能是一个可行的途径。试验表明,常规的混凝方法,对水中微量汞有一定的去除效果,但是所需投药量较     

松花江汞与甲基汞污染综合防治及其研究成果

美丽富饶的松花江是我国七大江河水系之一。早在50年代前，水质洁净，水量充沛，水产丰富，养育着几千万中华儿女。松辽大地因有松花江而骄傲、自豪，并得到了发展与繁荣！第一个五年计划开始，我国上了许多大中型建设项目。吉林市从此成为我国化工城之一。随着社会经济的迅猛发展，环境水体遭受污染也伴随而生，60年代末，已达到十分严重的程度。吉林化学工业公司电石厂醋酸车间乙醛工段等排汞单位，先后向松花江水体排入大量含汞废水。据中科院长春地理所研究表明，70年代初，排入松花江水体中的总汞已达149st，甲基汞达54t。污染高峰期平…     

地面水甲基汞环境质量标准研究概述

关于总汞的标准各个国家都有相应的规定．但地面水甲基汞环境质量标准，因研究的技术难度太大，目前，世界上还没有一个国家制订出来．我们是在松花江汞与甲基汞污染综合防治研究基础上，又经过一系列的“基准”研究后，按五类水体，研究制定出“地面水甲基汞环境质量标准”的。     

氢化物发生--原子荧光法测定地表水中汞含量研究

汞是具有蓄积作用的有害元素。我国现行的《地面水环境质量标准》(GB3838—2002)规定Ⅰ～Ⅴ类地面水体中汞的标准浓度为0．00005～0．001mg／L。目前国标方法中汞的测定多采用冷原子吸收法、双硫腙吸光光度法等．这些方法测定往往比较复杂，干扰因素多．影响测定结果。氢化物发生-原子荧光法测定一些元素目前尚无国标方法。但利用AFS-2202双道原子荧光光度计。通过氢化物发生-原子荧光法测定地表水中的微量汞，具有操作简便、干扰少、灵敏度高等特点。本文将我们研究试验成果总结如下：     

原子荧光法测定水体中汞时常见问题的分析与探讨

汞及其化合物广泛地存在于环境中,是具有积蓄作用的有害元素。天然水体中存在微量的汞,以前测定水中汞的方法主要有双硫腙光度法和冷原子荧光法,这些方法不仅操作繁琐,干扰多,而且有些还不同程度地引入对人体有害的有机溶剂,同时造成大量试剂的浪费,且灵敏度低,因而很难准确测定水中的痕量汞。氢化物发生一原子荧光技术是一种新兴的痕量分析技术,将汞与还原剂反应产生汞蒸气的方式进行分析。在测定水中汞时有快速、简便、灵敏度高、干扰少、线性范围宽、检测限低等优点。     

无汞布水器简介

目前在生物滤池中采用的旋转布水器也叫有汞布水器,布水器竖轴与旋转体衔接处用水银封闭。由于运行中水的压力不平衡,悬浮物的挤压以及布水器的检修,致使水银大量流入水体。根据我厂二十多年的运动情况表明,每年每台布水器流失水银15公斤以上,损失1万多元,更为严重的是造成了二次污染。为了解决二次污染的问题我们研制了新型的无汞布水器(见图1),以取代有汞布水器。一、无汞布水器的结构、工艺无汞布水器分为两部分,即中心固定部分(见     

氢化物发生-原子荧光光谱法测定水中痕量汞的实验研究

为了准确测定天然水体中汞的含量,文中对氢化物发生-原子荧光光谱法测定汞的实验条件进行了实验研究,考察了还原剂浓度和载流浓度对水中痕量汞测定结果的影响。结果表明,当还原剂硼氢化钾质量浓度为0.03%,用质量浓度为5%的盐酸作为载流时,仪器的灵敏度高、稳定性好,测量结果具有较高精密度和准确度。在采用实验确定的条件测定天然水中汞含量时,数据标准偏差小于0.004,加标回收率可达到98%~106%,具有较高的精密度和重现性,研究确定的条件可以用于天然水中痕量汞的测定。     

武汉城市湖泊汞的迁移与富集

对武汉远郊、城乡结合部和市区3种环境中6个湖泊的水、界面水、沉积物和生物(鱼)进行调查采样,用离心机离心出沉积物中的孔隙水,用原子荧光光谱仪进行汞含量测定。以土壤—水—界面水—孔隙水—沉积物—生物为轴线,探讨了汞在研究区土壤—沉积物系统、湖水—沉积物系统和湖水—界面水—孔隙水系统中的分配以及湖泊鲢鱼肉中汞与沉积物和水中汞的关系。建立了武汉城市湖泊汞的迁移、富集理想模式:湖泊水汞经悬浮物吸附沉淀而富集于沉积物中,沉积物中汞经化学转化传输给孔隙水;存在于悬浮物中的界面水汞,经解吸附后向湖水扩散而产生二次污染。湖水汞被鱼吸收而产生生物富集。从而得出湖水—界面水—孔隙水—沉积物、湖水—鱼的两种富集机制。     

A mercury transport and fate model (LM2-Mercury) for mass budget assessment of mercury cycling in Lake Michigan

LM2-Mercury, a mercury mass balance model, was developed to simulate and evaluate the transport, fate, and biogeochemical transformations of mercury in Lake Michigan. The model simulates total suspended and resuspendable solids (TSRS), dissolved organic carbon (DOC), and total, elemental, divalent, and methylmercury as state variables. Simplified processes among the mercury state variables including net methylation, net reduction of divalent mercury, and reductive demethylation are incorporated in the model. Volatilization of elemental mercury as a kinetic (phase transfer) process and partitioning of total, divalent, and methylmercury as a set of instantaneous equilibrium processes were also simulated. The model was calibrated to data collected in 1994 and 1995 and corroborated by comparing model output generated from a long-term model hindcast to total mercury measured in high quality sediment profiles. Model hindcast predictions of total mercury in the water column were within estimates of total mercury calculated from observed lake trout bioaccumulation factors. Using the model, a mass budget assessment of mercury cycling in the lake was conducted. Atmospheric deposition, including wet and dry (particle) deposition and absorption of gaseous divalent mercury, was the dominant source of total mercury to the lake, followed by sediment resuspension, and then tributary loads. The major loss mechanism of total mercury from the water was associated with the settling of solids, followed by net volatilization. Methylmercury loading associated with wet deposition was the dominant source to the lake, followed by tributary loadings, and in situ net methylation.     

SYG-II型智能冷原子荧光测汞仪在水环境监测中的应用

通过对SYG-II型智能冷原子荧光测汞仪的应用进行分析,探索出仪器使用的最佳测定条件,采用过夜消解的方法对水样进行消解,以便准确、快捷地测出水体总汞的含量。     

Assessment of fish mercury levels in the upper St. Lawrence River,Canada

The stretch of the St. Lawrence River near Cornwall, Ontario, Canada, between the Moses–Saunders power dam to the eastern outlet of Lake St. Francis in Québec, is currently listed as an Area of Concern (AOC), and has restrictive fish consumption advisories in place, largely due to high mercury levels. This study examined long-term temporal trends of mercury concentrations in northern pike, smallmouth bass, walleye and yellow perch from the St. Lawrence River, including the Cornwall AOC. In addition, differences in fish mercury concentrations among river sections were compared for each species using historical (1975–1979) and recent (2000–2011) data. Statistically significant declines in mercury concentrations were observed in all river sections for yellow perch (~ 40%), as well as in northern pike and walleye in at least one river section. For the river section encompassing the AOC, recent mercury concentrations are 33–59% lower than historical mercury concentrations for all four species. Further, a comparison of recent mercury concentrations between the AOC river section and other Ontario lakes/rivers suggests that AOC mercury values are within the 75th percentile of values for other Ontario water bodies in three of the four species considered. However, current fish mercury values for the AOC river section remain higher than one or more upstream river sections. These results indicate that recovery is still ongoing in this AOC.     

生物预处理技术在嘉兴地区给水厂的应用比较

对嘉兴地区主要给水厂近年来应用立体弹性填料、LT型悬浮球填料、YS型悬浮填料、卵石填料等的生物预处理工艺从填料及配套设施、工艺运行参数、运行效果、成本等方面进行了比较.认为弹性填料生物预处理更适用于低浊(50 NTU以下)、低氨氮(1.5 mg/L以下)原水,LT型悬浮球填料生物预处理适用于低中浊(100 NTU以下)、低中氨氮(2.5 mg/L以下)原水,YS型悬浮填料生物预处理及"SAF"滤池对低浊、中高氨氮(2.5 mg/L以上)原水有较好的适应性.最后探讨了弹性填料存在的短流、积泥,悬浮填料存在的部分填料流化不均匀,富氧的生物工艺单元内水生动物泛滥等问题.     

黄河泥沙吸附汞污染物静态试验

基于黄河天然混合沙的静水沉降吸附试验,研究了黄河泥沙对汞的吸附规律。结果表明:①质量浓度为5～25kg/m3的泥沙对汞的吸附在0.5 h内基本达到稳定,质量浓度为1 kg/m3的泥沙在0.5 h之后对汞污染物仍有一定的吸附能力,但吸附速率不大;②泥沙级配对汞的吸附有一定的影响,粗沙的吸附能力略低于细沙和中沙;③在中低含沙量时,含沙量增加会引起吸附表面积增加,吸附量和含沙量呈线性相关关系。     

Mass Balance Modeling of Heavy Metals in Saginaw Bay,Lake Huron

During the period 1976-1978, a study of hazardous materials in Saginaw Bay was conducted. This study included the fate and distribution of cadmium, copper, lead, and zinc in the bay. A spatially segmented, dynamic mass balance model was developed to describe concentrations of metals and suspended solids in the water column and in the sediments. A wind-driven resuspension mechanism was used to describe the sediment-water interactions. The distribution of metals in the water column was determined by equilibrium partitioning between the ambient suspended solids and the dissolved phase. Model output was calibrated to field data for the principal variables. Independent validation was obtained by comparing partition coefficients from the calibration to those calculated directly from the field observations. It was found that suspended solids were important in controlling the water column concentrations of the metals. The degree of control was a function of the partition coefficient between the metal and the solids, and the concentration of the solids. Adsorption of the metals to the solids was found to result in decreases to metals concentrations due to net sedimentation, as well as increases due to wind-driven resuspension. On an annual average basis, the net flux of the particulate components of all four metals was from the water column to the sediments except for copper in 1977.     

Variations in the Distribution of Suspended Particles During an Upwelling Event in Lake Michigan in 1980

To test the hypothesis that suspended fine-grained particles moving downslope within the nepheloid layer in Lake Michigan are periodically reintroduced into the nearshore and euphotic zones during upwelling events, temperature and transparency profiles were recorded and water samples analyzed for total suspended materials (TSM) during a strong upwelling event. The resultant data confirmed that there is periodic reintroduction of suspended materials into the nearshore and epilimnion during such events, and provided insight into the importance of the general resuspension process, especially in regard to differences between known sedimentation rates and the rate indicated by trap collections. Both upwelling and downwelling currents are disruptive processes that tend to keep the suspended particulates in motion and prevent them from rapidly becoming a permanent part of the bottom sediment. These currents redistribute suspended particulates and the associated chemical load, and may resuspend surficial sediments, especially from the slope and shelf regions. The reintroduction of fine-grained materials into the euphotic zone through upwelling events can play a large role in the long-term behavior and fate of persistent contaminants.     

压缩变形影响下的土-水特征曲线及其简化表征方法

非饱和土的本构关系研究需获得任意压缩变形条件下的土-水特征曲线,但试验测量往往只能给出特定状态下的土-水特征曲线。压缩变形改变土体孔隙分布特性,从而影响其土-水特征曲线。采用压汞技术、核磁共振技术、扫描电镜研究压缩变形条件下土体孔隙孔径分布的变化规律,基于实测及已有试验数据研究土-水特征曲线变化规律,通过孔径分布变化规律阐释压缩变形影响土-水特征曲线的机制。研究结果表明：在不同的压缩变形条件下,土体（单位颗粒质量）的累计孔隙体积分布整体上呈现“扫帚型”分布,质量含水量表示的土-水特征曲线也呈现相似的分布,二者变化规律较为一致,从而揭示了土-水特征曲线随压缩变形变化的内在机理。在此基础上,建议了一种压缩变形影响下的土-水特征曲线简化表征方法,其描述的土-水特征曲线与试验结果吻合较好。     

A comparison of mercury cycling in Lakes Michigan and Superior

Mercury cycling in Lake Superior and Lake Michigan was evaluated based on measurements of mercury levels, modeling of evasional fluxes, and development of first-order mass balance models. Total mercury, methylmercury, and dissolved gaseous mercury were measured on sampling cruises in Lake Michigan (2005) and Lake Superior (2006). Average total mercury concentrations in unfiltered surface water were higher in Lake Michigan (420 ± 40 pg/L) compared to Lake Superior (210 ± 20 pg/L). Methylmercury levels were below the detection limit in Lake Michigan. Larger sample volumes were collected to lower detection limits in Lake Superior in 2006 and methylmercury levels averaged 7 ± 6 pg/L. Dissolved gaseous mercury concentrations were also higher in Lake Michigan (27 ± 7 pg/L) compared to Lake Superior (14 ± 8 pg/L). Evasional fluxes were estimated using a two-film model for air–water exchange. The annual evasional flux in Lake Michigan was determined to be ~ 380 kg/yr from Lake Michigan and ~ 160 kg/yr from Lake Superior. Total mercury burdens in each lake were estimated to be ~ 2500 kg in Superior and ~ 2100 kg in Lake Michigan demonstrating that evasional fluxes play an important role in the mass balance of each lake, particularly Lake Michigan. A simple first-order mass balance model demonstrates the importance of air–water exchange and sedimentation as primary removal processes for Hg in each lake. Uncertainties in the mass balance model are highlighted due to lack of key data, particularly in Lake Superior.