吉林市排污河底泥的污染状况及其生态风险评价

以吉林市排污河中底泥为主要研究对象,布置12个监测断面35个代表性采样点,采集并分析了河道内底泥样品中8种重金属及16种USEPA优先控制的多环芳烃的含量,并分别采用地质累积指数法(I_(geo))、潜在生态风险评价法(PERI)、沉积物质量基准法(SQGs)对排污河底泥中污染物进行了生态风险评价。结果表明,该排污河底泥中重金属及多环芳烃均不同程度超过松花江水系沉积物背景值,其中Hg、Pb、Cu、As、NAP、ANT超标倍数分别为87.5、10.2、6.18、5.90、115.6和228.5;I_(geo)显示Hg的生态风险最大,I_(geo)达到了5.82,而Cd和Ni的风险较小,这与PERI中Hg风险最大的结果一致;SQGs评价结果表明由重金属及多环芳烃引起的污染会产生生物毒性,且不利生物毒性将频繁发生;(3)以上结果说明,该排污河呈现以Hg为主要风险因子的重金属与多环芳烃复合污染现象,在今后应加强底泥监测和定期清淤,从而推动区域生态环境的治理与恢复。     

大沽河青岛段地表水水质变化分析

采用2000年～2005年大沽河青岛段地表水水质监测资料,对大沽河青岛段地表水功能区水质进行了较全面地评价,发现近6年来大沽河青岛段地表水污染状况总体上呈好转趋势,主要污染物是COD、悬浮物和氨氮.结合大沽河青岛段水功能区水质达标率低的原因,提出了改善大沽河青岛段地表水环境的对策.     

大沽河青岛段地表水水质变化分析

采用2000年～2005年大沽河青岛段地表水水质监测资料，对大沽河青岛段地表水功能区水质进行了较全面地评价，发现近6年来大沽河青岛段地表水污染状况总体上呈好转趋势，主要污染物是COD、悬浮物和氨氮。结合大沽河青岛段水功能区水质达标率低的原因，提出了改善大沽河青岛段地表水环境的对策。     

新疆头屯河泥沙特征分析

根据头屯河楼庄子水库坝址处断面水文监测资料,采用实测资料推算法和输沙模数推算法,计算楼庄子水库坝址处多年平均输沙总量为499.94×104t。悬移质泥沙矿物组成为:石英8.43%,钠长石20.48%,微斜长石10.61%,方解石14.55%,白云石2.35%,绿泥石19.12%,伊利石24.46%;悬移质泥沙主要由粉土和黏土组成,其中0.075~0.25 mm的砂土占0.6%;0.005~0.075 mm的粉土占68.7%;0.005 mm的黏土占30.7%。     

山东大沽河(胶州段)水质特征初探

根据已建立的大沽河(胶州段)水质数据库，对其进行了水质现状分析和趋势评价。大沽河(胶州段)主要污染物是悬浮物、COD、氨氮。数据表明大沽河胶州段水质面临恶化，麻湾桥断面达三类水质标准，斜拉桥断面COD、悬浮物、氨氮指标劣于五类地面水质标准。引起麻湾桥段水质变化的主要因素是气象条件(降水)、农业面源，引起斜拉桥段水质变化的主要因素是工业生产和生活污水及气象条件。分析历年水质监测数据，可以看到污染有减轻的趋势，说明政府加强环境污染治理的措施是有成效的。     

巫山第四纪沉积物粒度特征研究

根据巫山WPT1与WS3剖面共同体41个样品粒度测试结果,分析了巫山第四纪沉积物的粒度特征。结果表明：巫山第四纪沉积物主要由5~50 μm粉砂组成,WPT1 与WS3剖面平均占53.44%、65.37%,为众数粒组;>50 μm砂粒平均含量分别占0.79%、15.54%;<5 μm粘粒平均含量分别占45.78%、19.09%。样品频率分布曲线均为单峰态,与粒度参数具有较高的一致性特征。粒度分析初步表明,巫山第四纪沉积物是风成大气粉尘堆积物。     

茅洲河清淤后底泥氮磷含量分析及其生态风险评价

为了解茅洲河清淤后底泥沉积物中总氮和总磷的含量、分布和环境污染风险,从清淤前相关研究中优选20个典型断面和36个取样点位,测试分析了底泥中的总氮、总磷含量,并对其环境污染风险进行了讨论与评价。结果表明,茅洲河底泥中总氮含量由高到低为：沙井河支流段>沙井河口—珠江口段>洋涌河水闸—沙井河口段,清淤后整个研究区底泥总氮含量较清淤前降低74.70%、总氮的内梅罗综合污染指数降为2.07,为中污染级,生态风险明显降低;清淤后底泥总磷的生态风险虽有所降低,但仍为重污染级,推测主要是由于清淤厚度不足及水体内磷的循环、迁移转换所致。     

海河干流入河排污口调查与评价

对2007年海河干流入河排污口进行了调查,采用等标污染负荷法进行评价。结果表明,分布在海河干流上8个入河排污口均存在超标排放问题,排污类型为工业废水和混合污水,以有机污染、富营养化污染和化工污染为主要特征。天碱泵站、大沽化工排水口、天碱排水闸为海河干流上的主要排污口,分别占海河干流等标污染负荷总量的27%、26%和17.4%。海河干流8个入河排污口达标污染总负荷为16.8亿t/a,即每年需要16.8亿t洁净水来稀释各排污口排放污水才能达到排放要求。     

大沽排污河入海口及其邻近海域水污染状况分析

通过对2014—2016年大沽排污河入海口及其邻近海域水环境的连续监测,分析了入海口及其邻近海域的水污染状况,结果显示:水环境呈现逐年改善的趋势;大沽排污河入海口主要受化学需氧量和五日生化需氧量的影响,化学需氧量3月开始逐渐上升至7月达到最高值,而后逐渐降低;邻近海域主要受到无机氮的影响。水环境的变化规律与陆地农田、工厂、生活污水等排放量密切相关,同时它们也是一个复杂的污染综合体,受到来自不同污染源、各类污染因子的影响。     

大沽河入海径流演化特征及其影响因素研究

为揭示胶东半岛大沽河入海径流量演化特征及其主要驱动因素,采用Mann-Kendall法与改进Mann-Kendall法、累积距平法与滑动t检验法、Morlet复小波变换等研究了1956～2016年大沽河入海径流量及其变化趋势、突变特征与变化周期;采用降水-径流双累积曲线法,定量计算了气候变化与人类活动对大沽河入海径流量变化的贡献率。结果表明：大沽河入海径流量呈显著减少趋势,平均减少速率为0.158 5亿m3/a, 1976年发生了由多到少的突变,变化的主周期为21 a;导致径流量减少的主要影响因素为人类活动,大规模水资源开发活动改变了流域水资源转化过程。研究成果可为胶州湾水资源开发利用保护和生态环境评价提供参考。     

Geochemistry of the Detroit River Sediments

The objectives of the investigation were to provide information on the concentration and distribution of metals in bottom sediments of the Detroit River and to study the association of metals with various sediment components. Concentrations of major elements (Si, Al, Ca, Mg, Na, K, Fe, Mn, and P) and metals (Co, Cr, Cu, Ni, Pb, and Zn), particle size distribution, and mineralogical composition were determined in 20 surficial sediment samples collected along the Detroit River in 1983. Significantly higher concentrations of metals in the Detroit River sediments than those reported in Lake St. Clair and Lake Erie sediments indicated input from sources in the river's drainage basin. Poor relationships exist between the metals and organic C and the metals and the silt-clay size fraction (< 63 μm). The association of metals with sediment particles was investigated by a separation of sediment into seven size fractions ranging from < 13 to > 63 μm. Zn, Ni, Cr, and Pb were accumulated in the < 13 μm size fraction. However, Cu and Cr concentrations were highest in the < 13 and 48 to 63 μm fractions. Quartz, feldspars, and calcite were found in the > 63 μm fraction. Dolomite, feldspars, and quartz were in the 13 to 63 μm fraction and the clay minerals illite, chlorite, and kaolinite were in the < 13 μm fraction. Concentrations and relationships among major elements reflected the mineralogical composition of different particle size fractions.     

Calcium Carbonate in Postglacial Lake Erie Sediment

Geotechnical, geochemical, electron-microscopic and biostratigraphic investigation of a 16.8–m long core of a postglacial lacustrine mud collected from the central Lake Erie basin revealed zones containing up to 30% calcite. These zones were associated with a very fine sediment, 80% of which was finer than 4 y.m. Shear strength values of the sediment ranged from 2 kN/m² near the lake bottom to about 9 kN/m² close to the Pleistocene boundary. The concentration of CaO was positively correlated with the concentration of inorganic C and Sr. The concentration of SiO₂, A1₂O₃, Fe₂O₃, K₂O, and Rb gradually decreased with depth. The major crystalline phases were illite (44 wt %), chlorite (10 -13 wt %), calcite (6 - 30 wt %), quartz (6 - 20 wt %), albite (6 - 9 wt %), K-feldspar (2 wt %), and dolomite (2 wt %). The shells of mollusc species present in the lower portion of the postglacial sedimentary column indicated that the carbonate-high sediments were deposited in warmer water than the carbonate-low sediments above and between them.     

湖泊底泥中磷的形态分布分析

目前自然水体富营养化程度越来越严重,其底泥中磷的含量也与日俱增。不同形态分布的磷在自然情况变化时表现出不同的特性,底泥中磷的形态分布对于控制水体中磷的浓度有着重要影响。本研究以五步化学分级提取法测定了12个湖泊底泥中磷的形态分布。结果表明：在底泥中与钙结合的磷较多,平均占总量的60％左右。射线衍射结果也表明12个样品中均含有较高比例的晶体钙矿物,平均含量约为49％。除了与钙结合的磷之外,其余的磷多数与铁、锰化合物相结合,其含量平均占总数的18％。黏土矿物及铝氧化物中结合的磷占总量的8％,与残余磷9％相当。松散吸附结合态的磷含量最低约占6％。研究磷的形态分布分析方法对于了解底泥中磷的形态分布以及磷在水体一底泥中的迁移转化规律有着重要意义。     

Mineralogical and geochemical composition of Late Holocene bottom sediments of Lake Onego

The analysis of both the mineralogical and geochemical composition and the stratigraphy of Holocene sediments of Lake Onego provided a novel interpretation of their genesis. Their mineral composition suggests that Holocene bottom sediments generally inherit the composition of terrigenous material that enters the lake with river runoff. The predominant authigenic minerals include biogenic opal from diatom skeletons, Fe-illite, and Fe-chlorite, which are the main iron mineral forms in bottom sediments of Lake Onego. Unstable suspension components (illite and chlorite) transform into their ferruginous varieties under humid climate conditions and high concentrations of iron and silicon in the lake waters. Both the presence of ferromanganese nodules in the uppermost part of bottom sediments of Lake Onego and their formation result from the location of the lake in the northern humid zone, geological composition of Fennoscandian crystalline rocks on the Lake Onego watershed, and the presence of an oxidative geochemical barrier into the lake sediment sequence. Late Holocene bottom sediments are represented by two types of sequences: 1) Fe-Mn enriched layers are formed near the sediment-water interface under oxygenated near bottom waters, and 2) such layers are not formed due to low concentrations of oxygen in water; but there are also non-laminated, homogeneous greyish-green silts, similar to those present in the lower parts of the first type of cores. Sedimentation rates (~0.10 cm y⁻¹) were determined by ²¹⁰Pb- and ¹³⁷Cs geochronologies.     

Differences in major ions as well as hydrogen and oxygen isotopes of sediment pore water and lake water

Isotopic and chemical compositions of pore water(PW) are highly relevant to environmental and forensic study. Five lake water(LW)samples and five sediment samples were collected to investigate the effects of pore sizes of sediments on PW chemistry and stable isotopes and determine mechanisms controlling their variations. Six pore water fractions were extracted from different-sized pores in each sediment sample at six sequential centrifugal speeds for chemical and isotopic analysis. The sediments consisted mainly of quartz, feldspar, and clay minerals. The hydrogen and oxygen isotopic compositions of PW are mainly controlled by the overlying LW, although the lag effect of exchange between overlying LW and PW results in isotopic differences when recharge of LW is quicker than isotopic exchange in PW. Identical isotopic compositions of PW from sediments with different pore sizes indicate that isotopic exchange of water molecules with different pore sizes is a quick process. The ratio of average total dissolved solid(TDS) concentration of PW to TDS concentration of LW shows a strong relationship with adsorption capacity of sediments, demonstrating that remobilization of ions bound to sediments mainly causes a chemical shift from LW to PW.Concentrations of Ca~(2+), Mg~(2+),and Cl~-in PW remain unchanged,while concentrations of Na~+,K~+,and SO_4~(2-) slightly increase with decreasing pore size. Chemical differences of PW from sediments with different pore sizes are governed by ion adsorption properties and surface characteristics of different-si zed particles.     

Bathymetry and siltation rate for Dokan Reservoir,Iraq

The Dokan Reservoir dam is a concrete cylindrical arch with gravity abutments, located on the Lesser Zab River about 60 km from the city of Sulaimani in north‐eastern Iraq. A bathymetric survey was conducted in November 2014 for a period of 10 days, using an echo sounder of 200‐kHz single beam. The survey results indicated an annual average sediment deposition of 3.8 million m³. Thirty‐two sediment samples were collected from the reservoir bed. The ratio of gravel, sand, silt and clay was 15:14:48:23, respectively. The reservoir bed is covered mainly with silt. The sediments are composed of silty clay (77.6%), silty sandy clay (10%), sandy gravely silty clay (1.2%) and gravely sandy silty clay (1%).     

Distribution of Major Elements and Metals in Sediment Cores from the Western Basin of Lake Ontario

An investigation was made of the relationship between the changes in metal concentrations in sediments with the distance from the Niagara River mouth and the chemical and physical characteristics of the sediments. Sediment cores were obtained at nine sampling stations in the western basin of Lake Ontario. In addition, surface sediment was collected at three stations on the Niagara Bar. Minerals present at all stations were silica, feldspars, illite/muscovite, chlorite, kaolinite, and calcite. Dolomite was found at some sampling stations as grains of 2 to 63 μm size. Significantly elevated concentrations of calcite (up to 20%) in the surface sediment (about 0 to 10 cm) at four sampling stations in the western basin and in the entire 25-cm sediment column at the Niagara River mouth indicated increased input of this mineral into Lake Ontario during the past 100 years. Furthermore, sediment concentration profiles of Zn, Pb, Cr, Cu, Ni, and especially Hg at all sampling stations indicated major transport of metals associated with the clay- and silt-size particles from the Niagara River into Lake Ontario (especially north-north-east and east of the river mouth). A significant decrease in Hg loading from the Niagara River during the past 20 years was also observed. Although smaller in magnitude, a similar decrease was found for Pb, Zn, Cr, Ni, and Cu loading. However, elevated Hg concentrations (up to 7 μg g～^l above background values) existed in the surface 10 cm of sediment at eight sampling stations.     

黏土矿物对泥石流体屈服应力影响的实验研究

一般情况下,泥石流体屈服应力随着泥沙颗粒体积浓度的增大而增大,同时随着黏粒黏性的增强而增强。在此研究基础上,以泥石流体屈服应力为研究目标,选取了蒙脱石、伊利石、绿泥石、高岭土等4种常见的黏土矿物为研究对象,通过改变泥石流体中泥沙颗粒体积浓度、黏土矿物成分及黏粒重量百分含量得出:1一般情况下,黏土成份对泥石流体屈服应力影响的强弱关系依次为蒙脱石伊利石绿泥石高岭土。2泥沙颗粒体积浓度和黏粒百分含量对泥石流体屈服应力的影响呈指数关系。3综合分析泥沙颗粒体积浓度、黏土矿物成份、黏粒百分含量与屈服应力的关系后获得了黏土矿物下屈服应力的关系式。4用野外调查资料验证了上述泥石流屈服应力与泥沙颗粒体积浓度、黏土矿物的关系,具有一定的准确性。     

Storm-induced Redistribution of Deepwater Sediments in Lake Ontario

High-resolution seismic reflection profiles, side-scan sonar profiles, and surface sediment analyses for grain size (% and, silt & clay), total organic carbon content, and carbonate content along shore-perpendicular transects offshore of Olcott and Rochester in Lake Ontario were utilized to investigate cm-thick sands or absence of deepwater postglacial sediments in water depths of 130 to 165 m. These deepwater sands were observed as each transect approached and occupied the “sills,” identified by earlier researchers, between the three deepest basins of the lake. The results reveal thin (0 to 5-cm) postglacial sediments, lake floor lineations, and sand-rich, organic, and carbonate poor sediments at the deepwater sites (> 130 m) along both transects at depths significantly below wave base, epilimnetic currents, and internal wave activity. These sediments are anomalous compared to shallower sediments observed in this study and deeper sediments reported by earlier research, and are interpreted to indicate winnowing and resuspension of the postglacial muds. We hypothesize that the mid-lake confluence of the two-gyre surface current system set up by strong storm events extends down to the lake floor when the lake is isothermal, and resuspends and winnows lake floor sediment at these locations. Furthermore, we believe that sedimentation is more likely to be influenced by bottom currents at these at these sites than in the deeper basins because these sites are located on bathymetric highs between deeper depositional basins of the lake, and the bathymetric constriction may intensify any bottom current activity at these sites.     

Sedimentation dynamics within a large shallow lake and its role in sediment transport in a continental-scale watershed

A comprehensive understanding of the sedimentation dynamics within Lake Winnipeg (surface area: 23,750 km²) and its role in sediment transport in the downstream river system was achieved by determining the properties of lake bottom sediment and patterns of sediment accumulation rates and by constructing a conceptual total (i.e., organic and inorganic) sediment budget. Net deposition was the governing process in the South and North Basins, whereas transportation dominated in the Narrows. The largest fluvial source of sediments to the lake, the Red River, supplies 35% of the total sediment load. Although accumulation rates in profundal zones progressively decreased northward from this source at the south end of the lake, high accumulation rates with low inventories of fallout radionuclides in the northern margin of the North Basin indicate a second sediment source, which was determined to be erosion of north shore banks, which accounts for up to 50% of the total sediment load to the lake. The nearshore-offshore gradient in bottom sediment properties in the North Basin confirmed that the signature of this source can reach at least 20 km southward into the lake. However, the properties of bottom sediments, sedimentation dynamics, and sediment budget suggested that some of the materials eroded from the north shore are exported without interaction with the lake bottom and this local sediment source is the dominant source for the downstream river system. It was concluded that Lake Winnipeg effectively disconnects the downstream Nelson River from sediment transport processes in its upstream watershed (953,250 km²).