沅江下游入湖段河床沉积物重金属污染特征

对沅江入湖沉积物进行钻探取样,利用等离子质谱仪（ICP-MS）对沉积物重金属进行分析。结果表明：重金属Ba、Sc、V、Th、U、Cu、Co、Ni、Cr等在沉积物中含量变化相对稳定,分布相对均匀;而Mn、Zn、Pb、Mo、Cd、Tl、Bi等重金属的含量变化大,分布不均匀。重金属含量柱状剖面变化特征及富集系数（EF值）的计算结果显示：沉积物中Cd达显著富集,而Sc、V、Mn、Pb、Bi等为中等富集程度。沉积物中存在3个重金属富集层,即中下部Pb、Tl、Bi富集层;中上部Pb、Cr、Ni、Cu富集层;浅表部V、Cr、Mn、Ni、Cu、Zn、Pb、Cd、Tl、Bi等多种重金属富集层。地累积指数（I_geo）和综合富集指数（EI）评价结果显示：沅江入湖沉积物重金属污染程度自河床深部向浅部,污染程度趋于增强,污染元素组合趋于由Pb-Bi的单一元素组合向由V-Cr-Mn-Ni-Cu-Zn-Pb-Cd-Bi组成的复合元素组合变化。且自上游向下游,沉积物重金属污染程度趋于降低。这种重金属污染空间变化特征与区域人为活动有关,值得进一步研究。     

新疆艾比湖湖泊沉积物元素地球化学记录及其生态环境意义

在对新疆艾比湖近代岩芯沉积物元素地球化学特征分析基础上,结合数理统计学方法对元素的来源及其反映的环境演变历史进行了探讨,最后利用Hakanson潜在生态危害指数法对岩芯表层沉积物中重金属的潜在生态危害进行了评估。结果表明：艾比湖岩芯沉积物中元素组成基本可以分为3类：第1类元素包括Fe、Mn、V、Ni、Li、Cr、K、Al、Co、P、Ti、Be、Pb、Cu、Ba和Zn,主要来源于流域陆源碎屑物,受流域侵蚀强度等因素影响,其中,Co、Cr、Cu、Ni、Pb、V、Zn等重金属以及营养元素P的富集系数1875-2011年由于受人类活动影响发生了较为明显的变化;结合重金属和营养元素P的富集系数有序聚类分析,以23 cm（1960年）为界可将艾比湖流域环境演变历史分为差异明显的两个阶段：（Ⅰ）1875-1960年,流域社会发展程度较低,人类活动导致的重金属输入少,流域环境主要受区域自然变化的影响;（Ⅱ）1960年至今,随着人口的增加,经济发展工农业活动增强,尤其是农业用水量增加,大多数重金属元素和P相对于前期有较为明显的增加。第2类元素有Mg和Na,主要来源于湖泊水中蒸发盐类结晶;由于绿洲农业的发展和灌溉用水的增加,在气候变化和人类活动的共同影响下,湖泊水位发生了剧烈的波动,造成Mg、Na等元素的波动变化。第3类元素包括Ca和Sr,受流域易溶元素风化淋溶作用控制。艾比湖沉积物中Co、Cr、Cu、Ni、Pb、V、Zn等7种重金属的潜在生态危害程度Ni（4.7） > Pb（4.6） > Cu（4.2） > Co（2.6） > Cr（1.7）=V（1.7） > Zn（1.1）,7种重金属均属于低生态风险。     

Past atmospheric Pb deposition in Lake Qinghai,northeastern Tibetan Plateau

Two short sediment cores were recovered from sub-basins of Lake Qinghai, China and were analyzed for concentrations of Pb and 16 other elements to determine historic, regional atmospheric Pb deposition on the Tibetan Plateau. Core chronologies, dating back to the eighteenth century, were established using activities of ²¹⁰Pb and ¹³⁷Cs. The 17 elements were divided into three principal components. Variations in concentrations of PC1 elements (Al, Cr, Cu, Fe, K, Mn, Ni, and Ti) demonstrate different patterns between the two cores, and are attributed to different sediment sources in the two sub-basins. PC2 elements (Ba, Ca, Na, and Sr) may be associated with the degree of catchment weathering and/or water chemistry. Four elements (Pb, Zn, P, and Co) are related to both PC1 and PC2, and reflect a mixture of natural and anthropogenic sources. The PC3 element is Mg in the north sub-basin, and is perhaps related to aragonite precipitation and/or increased farming. Elevated Pb concentrations in uppermost sediments of both cores signify a recent regional/global increase in anthropogenic Pb release into the environment. After subtracting lithogenic Pb, derived from rock weathering and/or dust and normalized to the background immobile element Ti, results suggest that excess, anthropogenic Pb is transferred to the lake and its sediments predominantly via the atmosphere. This anthropogenic atmospheric Pb is comparable in magnitude and displays similar variation patterns in the two cores, reflecting regional atmospheric deposition and local erosion. The average anthropogenic Pb deposition rate in Lake Qinghai since the 1960s has been ~12.2 ± 3.5 mg/m²/a, comparable with atmospheric Pb fluxes reported for sites elsewhere in the northern hemisphere.     

Recent heavy metal accumulation in Dongjiu and Xijiu lakes,East China

Taihu Lake has been recognized as a seriously contaminated waterbody with regard to Cd, Cu, Pb and Zn over the last two decades. The input of pollutants has increased due to economic and social development and population increase. Seventy percent of the pollutants in Taihu Lake comes from rivers, with the Yili River being a major source of pollutants. Lakes Xijiu and Dongjiu are connected to the Yili River and Taihu Lake and are sites where material is preferentially deposited because of hydrodynamic conditions. Sediment cores were collected from Xijiu Lake (core XJ-1) and Dongjiu Lake (core DJ-5) to investigate anthropogenic heavy metal contamination. Concentrations of Cu, Pb and Zn gradually increased since the late 1930s, peaked in 1970, and then dropped slightly. A sudden increase in concentrations of Cu, Pb and Zn occurred in 1991 and peaked again in 1996, then dropped markedly. Maximum concentration of Cd in core XJ-1 was 21.2 mg kg⁻¹ and mean concentration was 12.1 mg kg⁻¹. In core DJ-5, the maximum and mean concentrations were 6.9 and 5.4 mg kg⁻¹, respectively. Cr showed a pattern of variation different from the other heavy metals, but its concentration also dropped after peaking in 1996. Enrichment factors and anthropogenic factors revealed that human activities in the catchment played a key role in the heavy metal contamination. Increases in Cd, Cu, Pb and Zn concentration were caused by industrial development, particularly from non-ferrous metal smelting industries. The recent drop in Cd, Cu, Pb and Zn concentrations is attributed to pollution reduction measures instituted by the government. Cr was influenced by both natural and anthropogenic processes.     

青海湖流域沙柳河下游沉积物中重金属污染风险评价

对青海湖流域沙柳河下游沉积物中As、Cd、Pb、V、Cr、Mn、Ni、Cu和Zn 9种重金属元素的含量进行了分析测定,采用污染系数、富集系数、地累积指数和潜在生态危害指数评估了其污染程度。结果表明：无论在横向还是纵向上,重金属元素含量均低于青海湖土壤背景值;重金属元素污染系数和富集系数均小于2,且大多数样品的值低于1（高于1者多为Cd、Cu、Ni、Zn,且具高值）;地累积指数均为负值（除QB-19中Cd和Cu分别为0.10和0.02）;潜在生态风险因子大多低于30,潜在生态危害指数大多低于70。沙柳河下游沉积物尚未出现重金属污染,具有低的生态风险,但该流域重金属的人为排放确实存在（主要是Cd、Cu、Ni、Zn等）,而且在近代排放更为显著。     

Sources and chronology of fifteen elements in the sediments of lakes affected by metal deposition in a mining area

Sources and chronologies of metal contamination were studied in sediment cores of three lakes of the Rouyn-Noranda mining area (Québec, Canada) affected by atmospheric deposition of anthropogenic contaminants. One of the three lakes also received acid mine drainage. The sediments were dated using ²¹⁰Pb and ¹³⁷Cs and analysed for stable Pb isotope ratios and for total concentrations of 15 elements (Ag, Al, Au, Ca, Cu, Cd, Fe, Hg, Mn, Ni, P, Pb, S, Ti, Zn). Stable lead isotopic signatures helped to determine the quantitative contributions of different industrial Pb sources to our sampling sites. This source apportionment showed the dominant influence of the Rouyn-Noranda copper smelter in airborne Pb emissions for the decades following 1926, when industrialization began in the region. The smelter source had a low ratio of ²⁰⁶Pb/²⁰⁷Pb ranging between 0.90 and 1.05, as typical of the Abitibi Archean sulphides. The relationships between element (metal) sedimentary fluxes and anthropogenic Pb fluxes allowed us to infer the origin of the anthropogenic source. These relationships strongly suggest that the copper smelter was (and may still be) an atmospheric source of Cd, Cu, Pb, Zn, Ag and Hg to the surrounding lakes. Our study indicates that the efforts made by the Rouyn-Noranda copper smelter to reduce airborne emissions of metals have been translated in reduced atmospheric metal loadings to the surrounding lakes.     

连环湖马圈泡沉积物重金属污染及潜在生态风险

通过对连环湖马圈泡柱状沉积物重金属（Cr、Cu、Mn、Ni、Pb、Zn、Cd）等地球化学指标的分析, 对马圈泡沉积物污染历史进行了讨论。根据元素的变化趋势,结合颗粒组成指标,采用相关分析,富集状况及潜在生态风险评价,并辅以²¹⁰Pb、¹³⁷Cs测年数据,研究了自1937年以来该湖区沉积物重金属元素污染特征、来源、污染历史及污染程度。结果表明,1987年以前各元素含量变化趋势平稳,1987年至今,7种重金属元素含量均明显增加。重金属元素的来源包括自然来源和人为输入。从单向污染系数来看Cu、Ni、Cr、Pb、Zn属于中等污染强度,Mn、Cd达到了强污染程度;从综合污染系数来看,表层重金属元素主要为中等程度的污染。沉积物重金属污染历史与该区经济发展阶段相吻合可为其湖区生态环境的整治与改善提供基础性的数据资料。     

东莞市农田土壤和蔬菜重金属的含量特征分析

从东莞市采集118 个农田土壤样品和43 个蔬菜样品, 测试其中Cu、Zn、Ni、Cr、Pb、 Cd、As 和Hg 等8 种重金属元素的含量, 并结合GIS 制图和数据统计, 对农田土壤中重金属 的空间分布和来源、土壤和蔬菜中重金属的富集特征及其潜在风险进行了分析。结果表明, 农田土壤中Cu、Zn、Ni、Pb、Cd 和Hg 等元素含量均高于相应元素的广东省土壤背景值, 其中, Pb (65.38 mg kg^-1) 和Hg (0.24 mg kg^-1) 含量分别为其对应背景值的1.82 和2.82 倍。与我国《土壤环境质量标准》中II 级标准(pH < 6.5) 相比, 土壤中Cu、Ni、Cd 和Hg 含量样本超标率分别为3.4%、5.9%、1.7%和28%, 表现为以Hg 为主的多种重金属共同污染。土壤 中8 种重金属中Cu、Zn、Ni、Cr 和As 等元素主要来源于成土母质, Pb、Hg 和Cd 等元素主要与人类活动有关。空间分布上, Cu、Zn、Ni、Cr、Pb、As 和Hg 等7 种重金属含量呈现出西部高、东部低的特点, Cd 含量在西北部和东南部较高, 西南部较低。与《食品中污染物限量》(GB2762-2005) 等相关标准比较, 蔬菜中Ni、Pb 和As 含量的样本超标率分别为4.7%、16.3%和48.8%。蔬菜中重金属富集系数的顺序为: Cd > Zn > Cu > As > Ni > Hg > Cr > Pb。     

东莞市农田土壤和蔬菜重金属含量分析(英文)

A total of 118 of agricultural soil and 43 of vegetable samples were collected from Dongguan City,Guangdong,China. The spatial distribution,sources,accumulation charac-teristics and potential risk of heavy metals in the agricultural soils and vegetables were de-picted in details by three different approaches,including total contents of eight metal ele-ments in soils and vegetables,GIS maps and multivariate analysis of heavy metals in soils in the study. The results show that there are higher accumulation of heavy metals such as Cu,Zn,Ni,Pb,Cd and Hg in agricultural soils,and the contents of Pb (65.38 mg kg-1) and Hg (0.24 mg kg-1) are 1.82 and 2.82 times of the background contents of the corresponding heavy metals in soils of Guangdong Province,respectively. There are about 3.4% of Cu,5.9% of Ni,1.7% of Cd and 28% of Hg in all collected soil samples from all investigated sites which have overran the contents for heavy metals of the China Environmental Quality Standard for Soils (GB15618-1995,Grade Ⅱ ). The pollution characteristics of multi-metals in soils are mainly reflected by Hg. There are different sources to eight metal elements in soils,Cu,Zn,Ni,Cr and As are predominantly derived from parent materials,and Pb,Hg and Cd are affected by anthropogenic activities. The spatial distribution shows that the Cu,Zn,Ni,Cr,Pb,As and Hg contents of agricultural soils are high in the west and low in the east,and Cd contents are high in the northwest,southeast and low in the southwest in Dongguan. The ratios of vegetable samples which Ni,Pb and As concentrations higher than the Maximum Levels of Con-taminants in Foods (GB2762-2005) are 4.7%,16.3% and 48.8%,respectively. The order of bio-concentration factors (BCF) of heavy metals in vegetables is Cd Zn Cu As Ni Hg Cr Pb. It is necessary to focus on potential risk of heavy metals for food safety and hu-man's health from agricultural soils and vegetables in Dongguan City,Guangdong Province.     

Heavy metal concentrations in surficial sediments from Wadi El Natrun saline lakes, Egypt

Heavy metal concentrations of Wadi El Natrun saline lakes were investigated. Pb, Zn, Mn, Cu, Cd, Ni, Fe and Al were measured in surficial sediments. The heavy metal concentrations largely indicate the influence of weathering of terrigenous sources on land. In comparison with the average in sedimentary rocks, the concentrations of the heavy metals studied are higher than the global average sandstone. This is also reflected in the high enrichment factors. The heavy metal concentration in lakes II and III decrease in the order Pb > Zn > Cu, while in lake I the decreasing order is Cu > Zn > Pb. Sediments with microbial mats were found to concentrate heavy metals above background sediment values.     

青海湖典型湿地土壤重金属分布特征

重金属污染是当今土壤污染中影响面最广、危害最大的环境问题之一。对青海湖典型湿地土壤Cu、Zn、Pb、Cr、Fe、Mn 6种重金属元素的含量及分布特征进行了调查分析。结果表明:青海湖湿地土壤Cu、Zn、Pb、Cr、Fe、Mn 6种重金属元素的平均含量分别为16.34μg/g、46.82μg/g、15.65μg/g、58.49μg/g、14.57mg/g和33.08μg/g;青海湖区南北两岸典型湿地土壤重金属含量存在明显的空间差异。南北两岸样带上表层土壤Cu、Cr、Fe的含量变化均呈"W"形,Zn仅在青海湖北岸样带表现出"W"形,Mn元素含量在400m处为最低点,Pb没有表现出明显的变化特征;Cu、Zn、Pb 3种元素含量呈极显著相关,说明青海湖湿地土壤重金属污染有一定的同源性。     

博斯腾湖流域绿洲农田土壤重金属污染及潜在生态风险评价

新疆博斯腾湖流域绿洲采集195个农田土壤样品,测定其中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn等8种重金属元素的含量,基于地统计法分析农田土壤重金属空间分布规律,采用污染负荷指数（PLI）和潜在生态风险指数（RI）评价农田土壤重金属污染和潜在生态风险程度,并对重金属的来源进行讨论。结果表明：① 博斯腾湖流域农田土壤Cd、Cr、Cu、Ni、Pb和Zn含量平均值分别超出新疆土壤背景值的1.67倍、1.13倍、1.15倍、1.29倍、2.11倍和1.65倍。② 农田土壤中8种重金属元素空间分布基本呈现岛状分布格局,各金属元素在部分区域出现高值区,表明研究区人类活动对农田土壤环境具有负面效应。③ 农田土壤Pb呈现中度污染,Cd、Cr、Cu、Ni和Zn轻度污染,Mn轻微污染,As无污染。农田土壤重金属污染负荷指数的平均值为1.09,呈现轻度污染态势。④ 各重金属元素单项生态风险指数平均值从大到小依次为：Cd、Ni、As、Cu、Pb、Cr、Zn。综合生态风险指数平均值为18.63,处于轻微生态风险态势。从生态风险程度的区域差异来看,各县生态风险指数从大到小依次为：和硕县、博湖县、焉耆县、和静县。⑤ 农田土壤Cr、Cu、Mn、Ni与Zn主要受到土壤地球化学成因的控制,As、Cd和Pb主要受到人类活动的影响。Cd与Pb是研究区主要的污染因子,研究区农田土壤中Cd与Pb污染必须关注。     

Comparison and Analysis of Estimation Methods for Heavy Metal Pollution of Farmland Soils

Heavy metal pollution of farmland soils is a serious environmental problem. The accurate estimation of heavy metal pollution levels of farmland soils is very crucial for sustainable agriculture. Concentrations of heavy metal elements (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in farmland soils at 186 sampling sites in the Baghrash Lake Basin, NW China, were determined and analyzed based on the pollution index (P_i), the geo-accumulation index (I_geo), the enrichment factor (EF), the ecological risk index (ER), and the environmental risk index (I_er). The results of these five different estimation methods were compared and discussed. The obtained results indicated that the average concentrations of all the heavy metals in the farmland soils of the study area were lower than the Soil Environmental Quality of China (GB 15168-2018) levels, but the average concentrations of Cd, Cr, Ni, Pb, and Zn exceed the corresponding background values. Significant differences in estimation results existed between the five estimation methods. Based on the identified concentrations, the average P_i, I_geo, and EF values of the heavy metals in farmland soils decreased in the order of: Zn > Pb > Cd > Cr > Ni > Cu > As, whereas the average ER values decreased in the order of: Cd > As > Cu > Pb > Ni > Cr > Zn, and the average I_er values decreased in the order of: Cd > Cu > Zn > As = Pb > Cr > Ni. The pollution class values with different estimation methods were ranked as: P_i > I_geo = EF > ER = I_er. The obtained results suggest that the most appropriate estimation method and soil background values of farmlands should be used for better understanding the environmental quality of farmland soils. Overall, the EF and ER methods are recommended for assessing heavy metal pollution risks of farmland soils.     

近60年来星云湖沉积物中重金属污染记录

文章以星云湖08XY-4号钻孔岩芯为研究对象,通过对岩芯的137Cs和210Pb测年和多种元素组分(重金属元素Cd、Cr、Cu、Pb、Zn,成岩组分Fe、Mg、Al、有机质、碳酸盐和烧失量)的含量分析,系统研究了星云湖近60年来底泥中重金属的来源和污染历史,并借助地积累指数法对星云湖的重金属污染程度进行了评定。结果表明20世纪80年代末期以前,星云湖沉积物中元素Cd、Cr、Cu主要为自然来源,之后受当地工业化蓬勃发展的影响,人类活动对湖泊重金属含量的影响显著增强;元素Pb的污染历史早于20世纪50年代,与全球很多区域Pb污染要早于其它多数重金属污染这一现象相似;此外,可能受当地特殊的工业发展历史影响,1973～1991年期间星云湖遭受严重的Zn污染,平均污染指数值达到3.25,按Muller污染指数分级属4级偏重污染。综合来看,当前星云湖的污染程度仍然较轻,但是近期人类活动的影响已明显显现,需要加以重视。     

徐闻南山镇红树林沉积物及红树植物中重金属的累积特征与迁移规律

为探究重金属在红树林沉积物及红树植物中的分布累积及迁移规律，选取了徐闻南山镇红树林为研究对象，通过测定红树林沉积物及红树植物不同部位（根、茎、叶）的重金属质量分数，运用富集因子、生物富集系数、转移系数及相关性分析等方法进行分析。结果表明：1）红树林沉积物重金属质量分数表现为铬（Cr）＞锌（Zn）＞镍（Ni）＞铜（Cu）＞铅（Pb）＞砷（As）＞汞（Hg）＞镉（Cd），为中等变异程度；除了镍（Ni）元素外，其余7种重金属未超过国家一级标准，除了铅（Pb）元素外，其余7种重金属均超过广东省土壤环境背景值，说明研究区沉积物中重金属具有一定的积累效应。2）沉积物中砷（As）、铜（Cu）、锌（Zn）、汞（Hg）、镍（Ni）、铬（Cr）富集因子值均＞1.5，说明受到轻微人为活动影响；各站位镍（Ni）富集因子值均＞5，结合研究区背景，反映了镍（Ni）受到自然和人为输入的共同影响。3）白骨壤体内重金属主要集中在根部，而红海榄体内重金属在根茎叶中分布相对均匀。白骨壤根茎叶部位的大多数重金属质量分数远高于红海榄，说明白骨壤对重金属的吸附能力比红海榄强。汞（Hg）集中分布在植物的叶片部位，且与其他重金属之间相关性不明显；推测汞（Hg）主要通过叶片吸收进入植物体内，与交通运输污染有关。4）不同红树植物对不同重金属富集能力各异，白骨壤对重金属的富集能力表现为：镉（Cd）＞砷（As）＞铜（Cu）＞锌（Zn）＞汞（Hg）＞铅（Pb）＞镍（Ni）＞铬（Cr），红海榄表现为：镉（Cd）＞铜（Cu）＞汞（Hg）＞锌（Zn）＞铅（Pb）＞砷（As）＞镍（Ni）＞铬（Cr）。白骨壤和红海榄对汞（Hg）的运移能力都较强；红海榄对镉（Cd）的富集能力和转运能力都较强，而白骨壤对镉（Cd）富集能力较强，转运能力却较弱，这说明红树植物对重金属元素的富集能力与转运能力不存在正比关系。     

Heavy metal concentrations of agricultural soils and vegetables from Dongguan, Guangdong

A total of 118 of agricultural soil and 43 of vegetable samples were collected from Dongguan City, Guangdong, China. The spatial distribution, sources, accumulation characteristics and potential risk of heavy metals in the agricultural soils and vegetables were depicted in details by three different approaches, including total contents of eight metal elements in soils and vegetables, GIS maps and multivariate analysis of heavy metals in soils in the study. The results show that there are higher accumulation of heavy metals such as Cu, Zn, Ni, Pb, Cd and Hg in agricultural soils, and the contents of Pb (65.38 mg kg?1) and Hg (0.24 mg kg?1) are 1.82 and 2.82 times of the background contents of the corresponding heavy metals in soils of Guangdong Province, respectively. There are about 3.4% of Cu, 5.9% of Ni, 1.7% of Cd and 28% of Hg in all collected soil samples from all investigated sites which have overran the contents for heavy metals of the China Environmental Quality Standard for Soils (GB15618-1995, Grade Ⅱ). The pollution characteristics of multi-metals in soils are mainly reflected by Hg. There are different sources to eight metal elements in soils, Cu, Zn, Ni, Cr and As are predominantly derived from parent materials, and Pb, Hg and Cd are affected by anthropogenic activities. The spatial distribution shows that the Cu, Zn, Ni, Cr, Pb, As and Hg contents of agricultural soils are high in the west and low in the east, and Cd contents are high in the northwest, southeast and low in the southwest in Dongguan. The ratios of vegetable samples which Ni, Pb and As concentrations higher than the Maximum Levels of Contaminants in Foods (GB2762-2005) are 4.7%, 16.3% and 48.8%, respectively. The order of bio-concentration factors (BCF) of heavy metals in vegetables is Cd > Zn > Cu > As > Ni > Hg > Cr > Pb. It is necessary to focus on potential risk of heavy metals for food safety and human’s health from agricultural soils and vegetables in Dongguan City, Guangdong Province.     

澜沧江河床沉积物重金属污染评价

河床沉积物是河流水体与泥沙环境中重金属的主要积存载体,能反映水环境的重金属污染状况。本文选取澜沧江为对象,通过对澜沧江干流西藏和云南境内22个河段的河床沉积物重金属测定分析,得到了8种主要的重金属元素(Cr、Mn、Ni、Zn、As、Pb、Cu和Co)的含量,并采用沉积物富集系数法与地质积累指数法分别对所测得沉积物的重金属污染程度进行了评价。结果表明:①澜沧江干流大部分河段污染情况并不明显,但在中游的旧州和功果桥河段,因该区域的地质金属背景值和支流沘江流域铅锌矿开采,地表的重金属元素被雨水冲刷到该河段,导致沉积物重金属富集现象明显,出现了轻度到较强度污染;②澜沧江流域受人为干扰的区域集中于中游与下游,部分河段(功果桥附近)Cu、Pb和Zn等元素呈轻度或偏中度污染;③大坝对河流的阻隔效应使得干流沉积物重金属污染呈现片段化分布,河流沿岸城市化等人类活动对附近河段沉积物重金属污染状况也有较明显的影响。     

Heavy metals and phosphorus in tidal flat sediments of the Yangtze estuary

Concentrations of heavy metals (Cu, Pb, Zn, Cr and Cd), and phosphorous (P) were determined in surface tidal flat sediments of the Yangtze estuary and Shanghai coast. Results demonstrate that there were significant differences among the accumulation of the heavy metals in sediments, following the order: Zn > Cu > Cr > Pb > Cd. The spatial distribution and chemical forms of heavy metals in tidal flat sediments were closely related to the distribution of pollution resources (outlet of sewage) and the local sedimentary and hydrodynamic conditions. The dominated form of non-residual heavy metals is bound to Fe/Mn oxides, and the next form is bound to carbonates. Moreover, contents of total P in sediments range from 18.0 μmol.g⁻¹ to 31.4 μmol.g⁻¹ along the coastline, speciation of P in sediments was different, most of P in tidal flat sediments is associated with calcium phases (as Ca-P) similar to marine sediments.     

Sedimentary trace-element records of natural and human-induced environmental changes in the East China Sea

Total and chemical fractions of nine potential harmful elements (V, Cr, Co, Ni, Cu, Zn, Cd, Pb and Bi) and five lithogenic elements (Li, Sc, Rb, Cs and Th) in two ²¹⁰Pb-dated cores from the East China Sea were analyzed to investigate their applications in paleoenvironment studies, and to reconstruct the histories of environmental changes. The residual fraction was the largest pool of trace elements in sediments. Potential harmful elements exhibited distributions that were similar to residual fractions and the lithogenic elements, indicating their terrestrial origin mainly derived from the Changjiang River and the old Huanghe delta. In the coastal core, the distributions of total and residual trace elements recorded the dry/wet variations of the Changjiang runoff since the 1850s. Total potential harmful elements and lithogenic elements in the offshore core reflected fluctuations in the strength of the Jiangsu coastal current and the East Asia Winter Monsoon over the last century. The response mechanisms of sedimentary trace elements to the runoff and monsoon variations involved direct terrestrial input of elements and the impacts of TOC and sediment grain size on trace elements in sediments. Enrichment factors (EFs), chemical fractions and principal component analysis (PCA) were used to evaluate the anthropogenic disturbance on potential harmful elements. PCA identified the lithogenic fraction of trace elements in both cores and the anthropogenic/authigenic input in the coastal core. Increases of the EFs and labile fractions of Zn, Pb and Bi in upper sediments of the coastal core indicated increased anthropogenic input of Zn and Pb since the 1980s, and increased Bi input since the 1940s. Increases in oxidizable Co, Ni, Cu, Zn, Pb and Bi above 16 cm were related to eutrophication and elevated marine organic matter in inshore East China Sea after the 1990s. Sediment records in offshore did not show any evidence of anthropogenic influence on the potential harmful elements. This study revealed that trace elements in sediments were good proxies for natural and human-induced environmental changes in waters.     

开封古城不同朝代文化层重金属积累与污染分析

开封古城黄泛沉积形成的“城摞城”奇观为文化层重金属积累与污染分析提供难得的材料。在开封市城区（师专钻孔和医专钻孔）和郊区（金明钻孔）分别获取25 m连续岩芯,大部分按10 cm间隔分样,共获得657个沉积物样品。用ICP-MS和AFS方法测定样品Pb、Cd、Cu、Zn、Hg、As、Ni、Cr和Co含量。结合地层¹⁴C年代数据、考古发掘及历史文献记载,建立不同朝代文化层年代框架,开展文化层重金属积累与污染分析。结果表明：师专、医专和金明钻孔均存在战国、宋金、明早期、明中期、明晚期和清代6个文化层。文化层大部分重金属发生不同程度富集,以Hg富集最为明显,城区钻孔明早期以前文化层达到强富集至极强富集水平。绝大多数文化层发生了重金属轻度至中度污染,中度污染发生在城区钻孔的宋金文化层。城区钻孔的最主要污染重金属是Hg,其次是Cu、Pb和Zn;郊区钻孔的主要污染重金属是Cd、Cr、Hg和Pb。不同朝代文化层重金属污染程度与其人口密度呈正相关。明早、中、晚期文化层污染程度逐渐减轻的现象可能与明朝开封城复兴与频繁的黄河泛滥有关。