三峡库区香溪河库湾沉积物重金属污染特征

2010年3月在三峡水库香溪河库湾获取了无扰动沉积物柱状样,在香溪河口的长江干流(长江右岸)获取了表层沉积物样,现场进行了环境因子测量和室内粒度分析、矿物分析、重金属元素含量分析。沉积物矿物以绿泥石、伊利石和石英为主,占到全部矿物的65%左右。柱状沉积物pH值随深度增加呈现变小的趋势,Eh值也有随深度减少的趋势,反映了环境还原性加强。R-型因子分析结果表明:重金属元素的含量随粒径变细、绿泥石和伊利石含量增加而增加,而随石英、白云石含量增加而降低;且重金属元素含量变化与pH值密切相关,当pH值下降时部分重金属容易重新释放出来而进入环境中。库湾下游具有较中上游高得多的重金属含量,沉积物中重金属的污染程度为无污染到轻度污染,且轻度污染出现于下游至干流。三峡水库蓄水前香溪河沉积物中重金属含量顺序大致为Zn>Pb>Cu>As>Cd,而蓄水后香溪河及干流沉积物均表现为Cu含量高于Pb。     

太湖东北部沉积物理化特征及磷赋存形态研究

对太湖东部和北部8个沉积物样品进行了理化性质及磷赋存形态分析,在此基础上探讨了沉积物各理化性质与磷赋存形态间的相关关系。研究结果表明：太湖沉积物的总磷含量为307.43～1454.39 mg/kg,阳离子交换量为15.18～22.68 meq/100g土,有机质含量为1.66%～3.45%;颗粒组成以粉砂级和粘粒级为主,占总量的54.39%～76.83%;主要矿物组成为石英和长石,粘土矿物以伊利石/蒙脱石混层为主,其次是伊利石、绿泥石和高岭石;沉积物中氧化物以SiO2、Al2O3和TFe2O3为主,且它们的含量随沉积物中总磷含量的不同变化较大。磷的形态以无机磷为主,污染较重沉积物中铁/铝磷的含量明显升高,有机磷的比例降低,钙磷变化不大。沉积物的各理化性质与磷赋存形态间关系密切,随着沉积物中总磷含量的增加, 阳离子交换量和有机质的含量都逐渐升高,细颗粒含量（<2 μm）逐渐增多,铁/铝形态的磷在总磷中所占比例也逐渐增大。     

长江河口上边界床沙粒径的长期变化及其原因

大通水文站和泥沙观测断面位于长江河口的上边界。长江下游从大通（潮区界）至长江口门的距离长达680 km。20世纪80年代以来,长江流域日趋强烈的人类活动,显著改变了长江入海水文和泥沙数量和特性,从而对长江下游至河口动力地貌和动力沉积产生了显著影响。主要研究长江潮区界大通断面20世纪50年代以来床沙粒径的长期变化。1977~2004年床沙粒径 (〖WTBX〗d〖WTBZ〗50) 有一稳定增大的趋势,这主要是对上游河道悬沙来量持续减少的响应。值得注意的是床沙粗化过程是发生在该河床长期加积的背景上的。研究表明：导致床沙粒径粗化的原因,主要是上游河段进入本河段床沙粒径的增加和本河段冲淤过程中悬沙与床沙颗粒的交换。随着三峡水库的正常运行和其它大型水库的建设,预计未来几十年长江上游悬沙来量将进一步大幅度下降,可以预计,长江潮区界河段的床沙粒径将继续呈现增大的趋势。〖     

长江口及其邻近海域表层沉积物分布特征

根据长江口和杭州湾北部沉积物粒度分析数据，研究表层沉积物类型、分布以及分区特征。结果表明：沉积物的分布特征受水动力条件、地貌类型以及泥沙来源等因素的综合影响，长江口表层沉积物在纵向分布上，自西向东粒径从粗到细、分选程度从好至差，在横向上自北港－北槽－南槽，沉积物粒度逐渐变细；水流动力作用强的河槽和波浪作用强的口门浅滩沉积物粒度较粗，水动力较弱的河口边滩及口外海滨区沉积物则较细。根据沉积物分布特征可将长江口及其邻近海域分为河口分汊河段沉积区、河口拦门沙沉积区、口外海滨沉积区和杭州湾北部沉积区等4个沉积区。     

Adsorption and desorption of 85Sr and 137Cs on reference minerals, with and without inorganic and organic surface coatings

The adsorption properties of reference minerals may be considerably modified by the presence of the inorganic and organic coatings that are ubiquitous in soils. It is therefore important to assess the effect of such coatings to evaluate the relevance of adsorption studies on pure minerals. The adsorption of trace amounts of (85)Sr and (137)Cs has been studied in dilute suspensions for various minerals that are common components of soils: quartz, calcium carbonate, kaolinite, montmorillonite and illite. We studied the effect of coatings with either Fe or Al oxide with varying additions of soil-extracted humic or fulvic acid. Both adsorption and desorption were measured and data presented as distribution coefficients, Kd. No adsorption was detected on quartz and it was not possible to coat this surface. Adsorption on calcium carbonate was small and not influenced by coatings. Adsorption of Sr on the three clay minerals was very similar, enhanced by the Al-coating, but not affected by Fe and organic coatings. The presence of organic coatings decreased Cs adsorption on illite. Similar but smaller effects were seen on montmorillonite and kaolinite. Aluminum coating enhanced Cs adsorption on illite, whereas both inorganic coatings caused decreases in adsorption on montmorillonite, and there was no effect on kaolinite. Effects were not additive with mixed, organic-inorganic coatings. Adsorption of both Cs and Sr on all minerals was strongly irreversible, with Kd (desorption) being up to four-times greater than adsorption Kd. The ratio of desorption and adsorption Cs Kd values (an assessment of irreversibility) was inversely related to adsorption Kd. This is consistent with a decreasing contribution of high-affinity adsorption as adsorption increases, but may also reflect the partial loss of organic coatings during desorption.     

丹江口水库典型库湾及支流沉积物重金属污染分析及生态风险评价

对丹江口水库上游汉江支流及库湾沉积物中6种重金属元素的污染特征进行分析,采用效应阈值标准(NYSDEC)和Lars Hkanson潜在生态风险指数评价重金属的污染程度和环境风险。研究表明,库湾沉积物与支流沉积物中Ni、Pb含量较为接近;库湾沉积物中Cd、Cr、Cu、Zn含量分别高达186、2712、9991、4783 mg/kg,均超过支流沉积物中相应重金属含量2倍以上。各采样点表层（0~10 cm）沉积物中Pb含量均低于LEL值（最低效应阈值）,Cd、Ni含量均介于LEL值和SEL值（最高效应阈值）之间,而Cr、Cu、Zn含量均有超过SEL值的现象发生。考察沉积物重金属的富集程度发现各采样点表层沉积物中Ni和Pb均未发生富集,而Cd、Cr、Cu和Zn均存在不同程度的富集,其平均富集系数分别为712、180、163和284。根据重金属含量的相关性可知Ni和Pb主要来自于天然地球化学来源,而Cd、Cr、Cu和Zn则主要受人为源影响。以丹江口库区土壤（黄棕壤）中重金属背景值为参比,发现表层沉积物总体处于高生态风险,且以Cd生态风险为主;参与评价的5种重金属潜在生态风险程度顺序为Cd＞Cu＞Cr＞Zn＞Pb     

Distribution of PCBs, HCHs and DDTs, and their ecotoxicological implications in Bay of Bengal, India

Analyses of environmentally persistent pollutants like polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) isomers, and dichlorodiphenyltrichloroethane (DDT) and its metabolites in seawater and sediment samples collected from six locations along the east coast of India were carried out using High-Resolution Gas Chromatograph with High-Resolution Mass Spectrometer (HRGC-HRMS). Sediment and water from Chennai harbour and Cuddalore fishing harbour contained higher concentration of all the compounds. The highest concentration (6570 pg/g dry weight) of total PCB was found in sediment from Chennai harbour followed by sediments sampled in Chennai (opposite to Cooum River mouth) (505 pg/g), Cuddalore fishing harbour (335 pg/g) and Mandapam (251 pg/g). Concentrations in other locations were two orders of magnitude lower than Chennai harbour. A distinct PCB distribution pattern in sediment was observed between harbours and other locations. Greater concentrations of tetra-, penta- and hexachlorobiphenyls were observed in sediments of harbours and opposite to Cooum river mouth, but in other locations lower chlorinated biphenyls (di, tri and tetra-) were more. In seawater, HCH concentration was greater than DDT, but it was quite opposite in sediments. Elevated levels of DDT in sediment were observed only at highly populated urban locations, reflecting the local usage and input of this pesticide. Based on sediment/water quality criteria/guidelines, some coastal locations of the Bay of Bengal could be designated as being polluted by DDTs and gamma-HCH (lindane), but not by PCBs. This investigation reveals the declining trend on the environmental burden of persistent pesticides in Indian marine environment. Data on the organochlorine concentrations found in this survey can be used as reference levels for future POPs monitoring programme.     

Levels of elements in the surficial estuarine sediments of the Hugli River, northeast India and their environmental implications

The present paper is the first document of a detailed geochemical and mineralogical study of muddy to sandy mud estuarine sediments of the Hugli River collected from five different sites along its course in the coastal areas of West Bengal, northeast India. The present work attempts to establish the status of distribution and environmental implications of 52 elements in the surficial estuarine sediments and their possible sources of derivation. The level of both metallic and non-metallic elements shows a wide range of variation all along the course of the estuary and can be attributed to their differential derivation from the source rocks and differential discharge of untreated effluents originating from industrial, agricultural, aquacultural as well as domestic sewage. The element contents, particularly the heavy metal content in the sediments, are the lowest in the upstream part of the estuary at Diamond Harbor, whereas, these are slightly higher in the intermediate stretch of the estuary at Haldia to highest in the mouth of estuary at Gangasagar. These changes indicate that the metals that are carried from upstream find their ultimate depositional sink at the delta mouth near Gangasagar, where almost all the elements showed elevated values. The majority of the elements have their highest concentrations at Canning, a site within the tidal channel network of the Hugli-Matla drainage basin away from the direct influence of the Hugli River. This site is severely contaminated with huge organic load from domestic sewage, aquaculture, intensive trawling activities and agricultural runoff. Moreover, the site suffers from heavy siltation load causing an almost moribund condition of Matla River at this point. Equi-dimensional quartzo-feldspathic mineral grains are consistent components in the siliciclastic composition of the sediments and their sizes at each station are controlled by respective hydrodynamic conditions. Various flaky minerals (mica, chlorite, hornblende) are also present but show inconsistent patterns of distribution. These flaky minerals remain in suspension for a long time and do not follow the usual law of settling of particles depending on the hydrodynamic regime prevailing in the area. Presented data will serve as a baseline against which future anthropogenic effects may be assessed. A comprehensive account of heavy metal content in sediments from different coastal regions of peninsular India has also been presented for purpose of comparison.     

长江中游砂山的磁组构特征及古气候环境意义

为了建立长江中游风成砂的磁组构识别标志,讨论磁组构参数与古气候、古环境之间的关系,对新近发现的江西九江新港砂山剖面进行了野外考察和磁化率定向样品的采集和测试,结果表明：①新港风成砂剖面中砂层和古土壤化的亚黏土层的磁组构参数值具有较大的不同,亚黏土层的磁化率（〖WTBX〗κ〖WTBZ〗）在剖面中表现为峰值（均值143.27（10-6SI））,各向异性度（〖WTBX〗P〖WTBZ〗）值却表现为曲线的较低值段。砂层却与亚黏土层相反,〖WTBX〗κ〖WTBZ〗值为谷值（均值为2181（10-6SI））,〖WTBX〗P〖WTBZ〗值总体为高值段,但波动较大。②在新港风成砂剖面中大多数亚黏土层样品的磁面理度（〖WTBX〗F〖WTBZ〗）值大于磁线理度（〖WTBX〗L〖WTBZ〗）,而砂层中只有部分样品的〖WTBX〗F值大于L〖WTBZ〗,说明亚黏土层的磁面理发育程度较砂层的要好。③相对于河流和湖泊沉积物（河流沉积物长轴的倾角一般小于10°,短轴的倾角大于80°）而言,新港剖面风成砂的磁化率量值椭球体的长轴的倾角较大（22°～24°）,短轴的倾角较小（45°～51°）。④新港剖面风成砂的磁基质颗粒度（〖WTBX〗q〖WTBZ〗）的平均值（0668 8）比长江中游河流沉积物的〖WTBX〗q〖WTBZ〗值（024）偏大,反映风成砂的分选较河流沉积物的要差。上述特点可作为长江中游水成和风成沉积物的磁组构识别标志。⑤在325～262 m的地层剖面中共有9层发育程度不同的古土壤化的亚黏土层,说明在这一期间气候不仅有9次由干冷向暖湿的转变,且每次变化的强度也有所不同。〖     

丹江口水库表层沉积物不同形态氮的赋存特征及其生物有效性

为了揭示丹江口水库沉积物氮空间分布特征及其生物有效性,采用连续分级提取法研究了表层沉积物中可交换态氮(Exchangeable nitrogen,EN)、酸解态氮(Acid hydrolysable nitrogen,HN)及残渣态氮(Residue nitrogen,RN)的赋存特征,同时结合生物可利用态氮的含量,探讨了各形态氮对生物可利用态氮的贡献。结果表明,丹江口水库沉积物中总氮(Total nitrogen,TN)在425~5796 mg/kg之间,平均为1 319.32 mg/kg,其中EN、HN和RN的平均值相对比例为2.15∶1.95∶1,且各形态氮含量的空间分布呈入库河流大于库区开阔区域的特征,尤其在丹江、老灌河以及犟河-堵河入库口的含量较大。潜在矿化氮(Potential mineralized nitrogen,PMN)含量在40.20~1 468.95 mg/kg之间,平均为275.06 mg/kg,其中EN对丹江口水库沉积物PMN的贡献较大,比例在19.85%~90.80%之间,平均为63.47%。各形态氮在不同的水环境条件下发生迁移转化,保持着水-沉积物界面氮的动态平衡。     

近百年来长江中游牛轭湖沉积物铅元素富集记录及其环境意义——以长江荆江段牛轭湖群为例

通过对长江荆江段天鹅洲、中洲子和尺八3个牛轭湖钻孔沉积物进行短寿命放射性核素、粒度、磁学、铅元素测试与史志资料分析,在利用²¹⁰Pb比活度计算平均沉积速率,并结合史志资料与沉积物特征指示的事件进行沉积物年代校核基础上,运用地表物质非自然富集系数(EF值)方法,分析了牛轭湖沉积物铅元素富集状况。结果表明:三钻孔铅元素非自然因素富集特征基本一致,均起始于20世纪80年代初,并于2000年后呈下降状态,与我国铅污染历史及禁用含铅汽油的时间基本吻合;利用沉积物中铅元素非自然因素富集事件对沉积物进行断代分析,具有一定的可行性;牛轭湖河/湖沉积相转变未对沉积物铅元素的非自然因素富集产生影响,说明铅污染具有较广的“暴露面”。     

Diffusion of (226)Ra and (40)K radionuclides reproduced in underwater sedimentary columns in laboratory

The potential radiological impact of the increase of radioactive substances in the environment makes interesting the study of the migration of the contaminant radionuclides in soils and sediments, which are the last receiver system of these substances. By using a battery of sedimentary columns controlled in the laboratory, the diffusion of the (226)Ra and (40)K radionuclides has been studied, assessing their respective effective diffusion coefficients in a similar sedimentary medium. A decreasing temporal evolution is obtained, associated to the progressive 'fixation' of the radionuclides by the clay minerals of the sediment, followed by a constant tendency. A timescale of the 'fixation' by the sediment is determined, being of the order of days for (226)Ra and of the order of months for (40)K, so the progressive 'fixation' of (40)K by the clay minerals of the sediments is slower than in the case of (226)Ra.     

近30年来长江口北支及口外沉积特征及输移趋势

近30 a来长江口北支在自然和人类活动影响下，沉积物特征及输移趋势发生显著变化。研究基于2015年和20世纪80年代沉积物粒度调查资料，通过粒度对比、趋势分析等方法，探讨长江口北支及口外沉积特征与输移趋势。结果表明：长江口北支及口外沉积物类型以粘土质粉砂、砂质粉砂和砂为主，近30 a来平均中值粒径减小20%左右。其中，北支口内粒径减小约30%，表明北支口内整体为淤积环境；口外0~10 m水深区域粒径增加约25%，表现为风浪和潮流作用下的侵蚀特征；10 m水深外，粒径略有减小，沉积特征基本稳定。从沉积物输移趋势上看，北支崇头至灵甸港河段，沉积物较粗，以径流作用下的沉积为主；灵甸港至三条港河段，沉积物输移趋势向下指向三条港，其中灵甸港至三和港河段边滩粗、主槽细，径潮流交汇作用明显；三条港以下河段，沉积物以海域来沙为主，颗粒细，输移趋势指向上游；北支口外，0~10 m水深区域，沉积物粗化，沉积物随水深增加变细，其中0~2 m水深区域，砂含量占比超过90%；10 m以深离岸水域，沉积物输移趋势不显著。流域来沙减少和北支围垦工程建设，致使沿岸泥沙补给不足，口外浅滩泥沙在风浪和潮流作用下，一部分随涨潮流向口内输运，一部分随落潮流向外海扩散，构成北支及口外沉积物输移趋势格局。     

Sediment quality in Rio Guadiamar (SW, Spain) after a tailing dam collapse: contamination, toxicity and bioavailability

An integrated assessment of sediment quality in the Guadiamar River after a mining spill was conducted. The concentration of different metals and other conventional parameters were measured in sediments located along the river. Four sediment toxicity tests (Hyalella azteca 28-day survival and growth test; Chironomus riparius 10-day survival and growth test; Hexagenia spp. 21-day survival and growth test; and Tubifex tubifex 28-day reproduction and survival test) were carried out to determine the effects associated with the accidental spill. The geochemical fractions of 6 metals (Fe, Mn, Zn, Cu, Pb, and Cd) were determined to establish the bioavailability of the metals. The relationship found in the concentrations of metals associated with the mobile fractions of the sediments in the sites studied is similar to the toxic mud from tailing pond and confirms that the toxic effects are associated with the metals Zn and Cd originating from the spill.     

Diatoms in bottom sediments as indicators of pollution of urban aquatic ecosystems

Analysis of the concentrations of chemical elements and the composition of diatoms in the surface layer of bottom sediments has been performed in a small reservoir at the mouth of dammed river to evaluate the levels of pollution and the impact of toxicants on diatom communities of the river ecosystem. Data on interrelations between the concentrations of chemical elements and the relationship between inorganic pollution and accumulation of diatoms in bottom sediments as an indicator of development of the diatom assemblage have been obtained using linear correlation analysis and graphical plotting.     

Distribution and environmental impacts of some radionuclides in sedimentary rocks at Wadi Naseib area, southwest Sinai, Egypt

The present study examines the natural radioactivity in some sedimentary rocks and their associated environmental impacts at Wadi Naseib area. Exposure rate (ER), dose rate (DR), radium equivalent activity (Ra(eq)), external hazard index (H(ex)), internal hazard index (H(in)) and radioactivity level index (I(gamma)) were calculated. Wadi Naseib area is covered with sedimentary rocks of early to late Paleozoic age. These rocks are classified into two types: mineralized and non-mineralized sediments. The radiometric investigations revealed that uranium and thorium contents reached up to 710 and 520 ppm, respectively, in the mineralized rocks. This was attributed to the presence of some secondary uranium minerals. All sediments had low values of eTh and K content. The exposure and dose rates exceeded public permissible values in the mineralized sediments. Exposure and dose rates were within the safety range for workers and the public in the non-mineralized sediments. The expected environmental impacts may be low due to the limited occurrence of U-mineralization and corresponding areas for radiation exposure. Some precautions and recommendations were suggested to avoid any possible environmental impacts from areas and/or raw materials of high intensity of natural radiation sources.     

长江中下游土壤矿物组成与其土壤肥力

系统论述长江中下游地区土壤矿物组成的特点及其与该地区气候条件及成土母质条件间的关系，并深入论述土壤矿物组成对土壤肥力的影响。     

长江口潮滩沉积物中活性重金属的空间分异及控制机制

利用盐酸羟氨-25%醋酸溶液,提取了长江口潮滩沉积物中活性重金属含量。研究发现,长江口潮滩沉积物中活性重金属占总量的百分含量依次为Cu 26%,Pb 36%,Fe 7%,Mn 49%,Zn 32%,Cr 14%和Al 16%,沉积物基本未受到Cr污染,其余重金属污染程度处于中等偏下水平。除Zn、Cr外,其余活性重金属在夏季沉积物中的含量明显低于春季,其主要原因是夏季风暴潮将大量细颗粒泥沙及其富集的重金属带离潮滩进入了河口水体中。受点源污染排放及沉积物粒度影响,活性重金属在长江口南岸的浒浦、顾路和浦东机场出现峰值含量,且高潮滩含量明显高于中、低潮滩。在垂向上,重金属一般在沉积物表层或亚表层形成富集。在口门附近的滨岸潮滩沉积物中,Cu、Pb的空间分异主要受早期成岩作用的控制,在污染较为严重、水动力作用相对较弱的潮滩沉积物中,Cu、Pb的空间分异主要受沉积物中有机质含量变化的控制.     

Novel approach for assessing heavy metal pollution and ecotoxicological status of rivers by means of passive sampling methods

In order to study the pollution of fluvial ecosystems, it is necessary to analyze not only the levels of chemical contaminants in water, but also those accumulated in the sediment matrix, as well as to assess its ecotoxicological status. Eleven Catalan (Spain) river sections (one sampling point per river) located near urban and industrial areas were sampled during winter of 2009. Water pollutants were collected by using passive samplers as Diffusive Gradient in Thin-Films (DGTs) and Semi-Permeable Membrane Devices (SPMDs). Point water samples were also collected. The concentrations of potentially toxic elements (PTE) in water, filtered water, DGTs and sediment samples were analyzed. Aqueous and organic solvent extracts of sediments samples and organic extracts of SPMDs were performed to assess acute toxicity to Vibrio fischeri by Microtox(?), and chronic toxicity to the green alga Pseudokirschneriella subcapitata. Microtox(?) test was also performed with DGT extracts. The results show that metals content of Catalan river waters are below the freshwater screening US EPA benchmarks, excepting some industrial areas (for Hg, Pb, and Zn). In contrast, sediments levels of some rivers were far above freshwater sediment screening US EPA benchmarks (for Zn, As, Cr, Pb, Ni, Hg, and Mn), particularly in the most industrialized areas. A good correlation was found between toxicity values of extracts (from sediments and DGTs) and PTE levels in sediments. The current results support the suitability of using combined point and passive sampling methods for assessing the chemical and ecotoxicological status of aqueous environments.     

Artificial radionuclides in sediments of the Don River Estuary and Azov Sea

The Don River Estuary-Azov Sea system is an extension of the shallow continental shelf area of the Black Sea. A large data set of artificial radionuclides in bottom sediments of the Azov Sea has been compiled in order to examine the storage and migration of radionuclides within this highly restricted inland sea and to estimate the annual dose received by individuals in the local population who regularly consume fish. In recent years (1997-1999), the radionuclide content of surface sediments has been: 137Cs < or = 0.5-100 Bq/kg d.w. (mean = 33.8 +/- 25.9 Bq/kg d.w., n = 57), 90Sr = 0.2-5.7 Bq/kg d.w. (mean = 2.1 +/- 1.4 Bq/kg d.w., n = 34) and 239,240Pu = 0.31-0.51 Bq/kg d.w. (n = 2). In general, 137Cs activities increase with distance from the mouth of the Don River and correlate negatively with sediment grain size (r2 = 0.77, n = 21). The annual 137Cs-derived dose received by an individual through the trophic chain water-fish-humans (approximately 10(-6) Sv/yr) is well below regulatory recommended limits, indicating that current levels of radioactivity in the environment pose no threat to commercial fisheries operations for the bordering nations of Russia and Ukraine.