Comparison between BCR sequential extraction and geo-accumulation method to evaluate metal mobility in sediments of Dongting Lake,Central China

The form in which a metal exists strongly influences its mobility and thus, the effects on the environment. Operational methods of speciation analysis, such as the use of sequential extraction procedures, are commonly applied. The Dongting Lake, the second largest fresh-water lake in China, contains three China wetlands of international importance, the East Dongting Lake, South Dongting Lake, and West Dongting Lake. In this work, an optimized BCR sequential extraction procedure was used to assess the environmental risk of Cd, Cr, Cu, Ni, Pb and Zn in contaminated sediment of the Dongting Lake. The procedure was evaluated by using a certified reference material, BCR701. The results of the partitioning study indicated that in the lake sediments, more easily mobilized forms （acid exchangeable） were predominant for Cd, particularly in the samples from the East Dongting Lake. In contrast, the largest amount of Pb was associated with the iron and manganese oxide fractions and Cu, Zn, Cr, and Ni analyzed were mainly distributed in residual phase at an average percentage greater than 60% of the total metals. The potential risk to the lake＇s water contamination was highest in the East Dongting Lake based on the calculated contamination factors. On the other hand, the total metal content was determined as well by inductively coupled plasma and mass spectrometry （ICP-MS） and assessed by using geo-accumulation index. The assessment results using geo-accumulation index were compared with the information on metal speciation. Both were correspondent with each other.     

Study on Dissolved Trace Metals in Sea Surface Microlayer in Daya Bay

Glass-plate sampling during 1988- 1999 in Daya Bay and suitable corresponding analytical methods were used for the measurement of dissolved trace metals, dissolved organic carbon, biological oxygen demand, chemical oxygen demand, salinity of the sea surface mierolayer and subsurface water. Apparent enrichment mechanism and diurnal variation have been revealed for dissolved trace metals in the microlayer in Daya Bay. The more dissolved organic matter was enriched in the sea surface microlayer, the more dissolved trace metals were enriched in the layer. The organic matter played an important role in the enrichment process. The diurnal variations of dissolved trace metals showed that their concentration was apparently inversely related to the tide activity that the concentration was low during rising tide, but high during falling tide. The behavior of dissolved trace metals expressed by the diurnal variation was clearly opposite to that of salinity.     

Analysis of Cu,Co, V and Zn in coastal waters of the East China Sea by inductively coupled plasma mass spectrometry (ICP-MS)

In this study, a simple method for the simultaneous determination of trace metals(Cu, V, Co, Zn) in coastal seawater using the Mg(OH)2 coprecipitation inductively coupled plasma mass spectrometry(ICP-MS) was developed. This multi-element method enables the simultaneous extraction of four metals, particularly Co and V. The recoveries of Cu, Co, V and Zn after Mg(OH)2 coprecipitation were 73%, 96%, 94% and 92%, which means that our procedure was well-suited to the determination of these four trace metals. The detection limits were 3.81, 0.18, 6.09 and 1.91 nmol L-1, respectively. Then, applying this method to the simultaneous determination of these four metals in coastal water samples from the East China Sea revealed that the concentrations of Cu, Zn, Co and V were higher in bottom waters compared to water at other depths, and higher concentrations were generally observed at the Yangtze River estuary. Additionally, example vertical profiles of dissolved trace metal concentrations for the East China Sea in spring and autumn are compared. These findings indicate that Zn had the greatest seasonal variation followed by Cu, V and Co. For Zn and Co, the concentrations were higher during spring than during autumn. For Cu and V, the seasonal variation in the concentrations was opposite.     

Preliminary comparison of trace metals in coastal aerosols between Qingdao and Liverpool

Aerosol samples were collected at two coastal suburban stations, Qingdao （China） in 1995-1996 and Liverpool （U.K.） in 1995, respectively. The samples were analyzed to determine the concentrations of trace metals （Cr, Zn, Cu, Co, Ni, Pb, V, and Cd） as well as A1, Fe and Mn. Data were examined to understand the difference of trace metals in aerosols between coastal zones downwind the developing area （near the Yellow Sea） and developed region （near the Irish Sea）. The results show that most elements at Qingdao have levels 4-5 times higher than those at Liverpool, particularly for the crust-dominated elements （e.g. Al, Fe and Mn）. Moreover, the aerosol composition at Qingdao is higher in spring than in summer, underlying the influence of westerlies and local emissions in combination, whereas seasonal change of aerosol composition is not significant at Liverpool. The enrichment factors for the crustal source elements （EFcrust） at Liverpool are much higher than those at Qingdao. The contributions from the pollutant source （Rp） for some trace metals like Cu, Pb, Zn and Cd are 〉90% at Qingdao and Liverpool, suggesting overwhelming anthropogenic contributions to these metals. The contributions from crustal source （Re） for trace metals tend to increase with higher aerosol levels and Al concentration at Qingdao, indicating a good correlation between the crust-dominated component and the air mass. At Liverpool, the Rc values for trace metals are positively correlated with Al concentrations instead of with aerosol mass, suggesting that Al in aerosols represents the crustal component even though the aerosols come from different sources.     

柞水银铅矿地表径流沉积物中污染物相态分析

采自柞水银铅矿地表径流６个沉积物样品,用连续提取法提取了金属元素的５种化学相态（可交换相、碳酸盐相,铁锰氧化物结合相,有机质－硫化物结合相及残渣相）,测定了各相中铜铅锌含量,分析了其分布特征。结果表明,在河流沉积物中,铜主要以残渣相和有机质相存在,铅、锌主要为铁锰水合氧化物相和碳酸盐相。在此基础上,对矿山开采中环境影响进行了讨论。     

BIOCHEMICAL STUDIES ON “SUB-MICROMETER PARTICLES" AT DAYA BAY I. STUDY ON CONCENTRATION, DISTRIBUTION AND CORRELATION OF TRACE METALS IN DIFFERENT SIZE FRACTIONS

ＩＮＴＲＯＤＵＣＴＩＯＮＣｏｌｌｏｉｄｓ (ｏｒｓｕｂ ｍｉｃｒｏｍｅｔｅｒｐａｒｔｉｃｌｅｓ)ａｒｅｏｐｅｒａｔｉｏｎａｌｌｙｄｅｆｉｎｅｄａｓｐａｒｔｉｃｌｅｓｂｅｔｗｅｅｎ 1ｎｍａｎｄ1 μｍ (Ｖｏｌｄ ,Ｒ .Ｄ .ａｎｄＶｏｌｄ ,Ｍ .Ｊ.,1 983) .Ｔｈｅｄｉｓｔｒｉｂｕｔｉｏｎｂｅｔｗｅｅｎ“ｄｉｓｓｏｌｖｅｄ”ａｎｄ“ｐａｒｔｉｃｕ ｌａｔｅ”ｐｈａｓｅｉｎａｑｕａｔｉｃｃｈｅｍｉｓｔｒｙｕｓｅｄｔｏｂｅｄｅｆｉｎｅｄｂｙａｆｉｌｔｒａｔｉｏｎｗｉｔｈ 0 .45 μｍｐｏｒｅｓｉｚｅｆｉｌｔｅｒｓ.Ｔｈ…     

Application of ICP-AES with microwave digestion to detect trace elements in oysters from Jiaozhou Bay, China

Using ICP-AES with microwave digestion, we determined the concentrations of 16 trace elements in oysters from six sampling points in Jiaozhou Bay.The distributions of the wholesome elements Zn, Fe and Mn, and heavy metals such as As,Cd,Hg and Pb were studied.The oysters collected are all rich in the wholesome trace elements,and the oysters from Licun River have the highest concentrations of the three wholesome trace elements.The concentrations of heavy metals in oysters from Licun River are the highest and those from Hongdao are the lowest. Compared with the domestic and foreign sea-areas,the heavy metal contents in the oysters from Jiaozhou Bay are less in amount than those from some developed countries, and more than those in Southeast China.This implies that the Jiaozhou Bay’s oysters have been polluted by the environment to some extent.     

Chemical characteristics of aerosols in the Kuroshio area

Aerosol samples were collected with a Sierrer Model 235 cascade impactor in the marine atmosphere over the Kuroshio area in consecutive four seasons from 1987 to 1988. Na, Cl, Al, V, and water soluble and acid soluble Mn, Fe, Pb, Cu, V, Cd were determined by neutron activation analysis and atomic absorption spectrophotometry, respectively. Seawater source chemical species in the aerosols appeared in high content in large over 3.6 μm diameter particles, and crustal source vanadium appeared in 3.6 μm diameter particles, but pollution source vanadium appeared in less than 0.52 μm diameter particles. Trace metals in the aerosols mostly had the highest concentration of water soluble metals on fine particles, and acid soluble metals on large particles. The concentrations of trace metals in the aerosols were higher in autumn and winter, lower in spring and summer. Funds from the National Natural Science Foundation of China.     

RELATIONSHIPS BETWEEN FRACTIONATIONS OF Pb, Cd, Cu, Zn AND Ni AND SOIL PROPERTIES IN URBAN SOILS OF CHANGCHUN, CHINA

1IN T R O D U C T IO N With therapiddevelopment of urbanizatio,nurban land was exploitedand utilizetdoform differendtomains be- ing subjectto many potentialpollutionsourcessuch as vehicleemission, industrialactivitieasnd household garbage.Particularl, yur…     

Trace metal anomalies in bleached Porites coral at Meiji Reef,tropical South China Sea

Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium(Cr), copper(Cu), molybdenum(Mo), manganese(Mn), lead(Pb), tin(Sn), titanium(Ti), vanadium(V), and yttrium(Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea(SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events.     

GEOCHEMICAL CHARACTERISTICS OF SEDIMENTS AND ANALYSIS OF THE CHANGJIANG ESTUARY ENVIRONMENT

Analysis of material from three 55- cm long cores collected with box corer m summer of 1988 in the Changjiang Estuary region yielded data on the sedimentation rate, granulometric composition and contents of carbonates, organic matter, Al, Fe, Mn, Zn, Cu and Pb there. Subsequent study of the data led to the conclusion that there is no obvious pollution in the region based on the absolute value of the content of heavy metals, but the region is in potential danger of being polluted as seen by the obvious increase of sedimentation flux of heavy metals to and the enrichment of them on the surface sediment during the last several years, e.g. Pb increased by 10-20μg/g, Zn by about 30μg/g, Cu by 5-10μg/g and Mn by 150μg/g.A ferromanganese redox interface was found at about 40 cm depth of sediments where Fe and Mn and associated trace metals are enriched. The trace metals such as Zn, Cu have (but Pb does not) the same source, forms, displacement mechanism and geochemical behaviours as those of Fe and Mn in t     

Cultivated land information extraction in UAV imagery based on deep convolutional neural network and transfer learning

The development of precision agriculture demands high accuracy and efficiency of cultivated land information extraction. As a new means of monitoring the ground in recent years, unmanned aerial vehicle (UAV) low-height remote sensing technique, which is flexible, efficient with low cost and with high resolution, is widely applied to investing various resources. Based on this, a novel extraction method for cultivated land information based on Deep Convolutional Neural Network and Transfer Learning (DTCLE) was proposed. First, linear features (roads and ridges etc.) were excluded based on Deep Convolutional Neural Network (DCNN). Next, feature extraction method learned from DCNN was used to cultivated land information extraction by introducing transfer learning mechanism. Last, cultivated land information extraction results were completed by the DTCLE and eCognition for cultivated land information extraction (ECLE). The location of the Pengzhou County and Guanghan County, Sichuan Province were selected for the experimental purpose. The experimental results showed that the overall precision for the experimental image 1, 2 and 3 (of extracting cultivated land) with the DTCLE method was 91.7%, 88.1% and 88.2% respectively, and the overall precision of ECLE is 90.7%, 90.5% and 87.0%, respectively. Accuracy of DTCLE was equivalent to that of ECLE, and also outperformed ECLE in terms of integrity and continuity.     

CHEMICAL CHARACTERISTICS OF AEROSOLS IN THE KUROSHIO AREA——II.CHEMICAL FORMS AND SIZE DISTRIBUTIONS OF TRACE METALS

Aerosol samples were collected with a Sierrer Model 235 cascade impactor in the marine atmosphere over the Kuroshio area in consecutive four seasons from 1987 to 1988. Na, G, Al, V, and water soluble and acid soluble Mn, Fe, Pb, Cu, V, Cd were determined by neutron activation analysis and atomic absorption spectrophotometry, respectively. Seawater source chemical species in the aerosols appeared in high content in large over 3.6um diameter particles, and crustal source vanadium appeared in 3.6um diameter particles, but pollution source vanadium appeared in less than 0.52um diameter particles. Trace metals in the aerosols mostly had the highest concentration of water soluble metals on fine particles, and acid soluble metals on large particles. The concentrations of trace metals in the aerosols were higher in autumn and winter, lower in spring and summer.     

Trace metal anomalies in bleached <Emphasis Type="Italic">Porites</Emphasis> coral at Meiji Reef,tropical South China Sea

Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium (Cr), copper (Cu), molybdenum (Mo), manganese (Mn), lead (Pb), tin (Sn), titanium (Ti), vanadium (V), and yttrium (Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea (SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events.     

Influences of hydrological regime on heavy metal and saltion concentrations in intertidal sediment from Chongming Dongtan,Changjiang River estuary,China

The tidal flat along the Changjiang(Yangtze) River estuary has long been reclaimed for the agricultural purposes, with the prevailing hydrological conditions during such pedogenic transformations being of great importance to their successful development. In this study, samples of surface sediment from Chongming Dongtan, situated at the mouth of the Changjiang River estuary, were collected and analyzed in order to understand how hydrological management can influence the concentrations of heavy metals and salt ions in pore water, and chemical fractionation of heavy metals during the reclamation process. We performed a series of experiments that simulated three dif ferent hydrological regimes: permanent flooding(R1), alternative five-day periods of wetting and drying(R2), continuous field capacity(R3). Our results exhibited good Pearson correlations coefficients between heavy metals and salt ions in the pore water for both R1 and R2. In particular, the concentrations of salt ions in the pore water decreased in all three regimes, but showed the biggest decline in R2. With this R2 experiment, the periodic concentration patterns in the pore water varied for Fe and Mn, but not for Cr, Cu, Pb and Zn. Neither the fractionation of Ni nor the residual fractions of any metals changed significantly in any regime. In R1, the reducible fractions of heavy metals(Cr, Cu, Zn and Pb) in the sediment decreased, while the acid extractable fractions increased. In R2, the acid extractable and the reducible fractions of Cr, Cu, Zn and Pb both decreased, as did the oxidizable fraction of Cu. These data suggest that an alternating hydrological regime can reduce both salinity and the availability of heavy metals in sediments.     

ICP-AES测定金属元素铜活动态及其初步应用

金属元素活动态是我国5种深穿透地球化学技术中应用最广的方法之一。此方法是通过提取地表土壤一定深度介质中元素活动态的微弱隐伏矿信息而找寻隐伏矿,属于通过直接信息找矿,目前该方法的标准化程度不高。为将铜元素活动态应用于地质找矿,该文对铜元素4个活动态的相态(水浸出态、粘土吸附态、有机链合态、铁锰氧化物态)循序提取的条件及ICP-AES测定技术进行了研究,包括采样深度、分析样品粒度、样品存放时间、提取条件、测定干扰等,通过对铜活动态提取液处理方法的改进,提高了分析速度和分析数据的精度。由实验数据计算出各相态方法的检出限和精密度RSD(n=10),水浸出态为0.079mg/L,13.90%~22.49%;粘土吸附态为0.275mg/L,11.99%~23.29%;有机链合态为0.362mg/L,10.70%~57.27%;铁锰氧化物态为0.230mg/L,17.83%~38.61%。该方法操作方便,精密度较好,应用于碑楼隐伏铜矿的野外探测实验,探测结果所圈定的综合异常与实际矿体的水平投影相符,取得了较满意的试验效果,该方法可应用于不同地质景观区。     

元素的环境化学与地球的温室效应

本文讨论了一些重要元素的环境化学特征和一些重要金属和痕量元素对人类健康的影响。在地球温室效应一节中重点叙述了本世纪初以来CO_2浓度剧烈的增加,使地球的气候变暖,海洋表面的温度也上升了0.6±0.3℃。因此,必须严格限制CO_2排放。还讨论了对流层中的臭氧是一种对植物有害和对人体不利的污染物,然而平流层中的臭氧却是地球表面免受紫外线辐射的重要屏障。因此,应防止CFCl_3和CF_2Cl_2的一组化学剂,以便保护臭氧。     

基于深度学习模型的城市高分辨率遥感影像不透水面提取

不透水面是衡量城市生态环境状况的重要指标。城市土地利用的复杂性和不透水表面材料的多样性,导致直接从高分辨率遥感影像中提取不透水表面具有挑战性。针对城市尺度高分辨率遥感影像的不透水面提取要求,本文提出基于深度学习的城市不透水面提取模型。首先,利用深度卷积神经网络对影像特征进行提取;然后,根据其邻域关系构建概率图学习模型,进一步引入高阶语义信息对特征进行优化,实现不透水面的精确提取。本文选取武汉市为实验区,以高分二号卫星遥感影像作为数据源,完成了不透水面专题信息提取,其中自动提取准确率在建成区为89.02%、在城乡结合部为95.55%。与随机森林（RF）和支持向量机（SVM）等经典方法对比,结果表明深度学习不透水面提取方法有较高的提取精度和细节准确性,建成区的总体精度相比于RF和SVM算法分别提升2.18%和1.68%。最后,对武汉市各主要行政区不透水面信息进行统计和分析,结果表明其中江汉区和武昌区2个核心主城区不透水面占比超过60%,并对武汉市现状和发展规划特点进行了讨论。本文研究成果可为海绵城市和生态城市的建设提供基础技术支撑和数据参考。     

Biochemical studies on “sub-micrometer particles” at Daya Bay I. Study on concentration, distribution and correlation of trace metals in different size fractions

This paper discusses the measured concentrations of trace metals in different size fractions at Daya Bay, and describes the features of distribution and variation of lead, copper and cadmium there. On average, 16% of Pb, 10% of Cu and 8% of Cd which previously would have been considered in the dissolved phase are actually associated with colloidal material. Thus, past studies overestimate the dissolved trace-metal concentration. The correlation between the colloidal fraction and the so-called dissolved fraction suggests the significant role of colloidal material in the biogeochemistry of trace metals. Project supported by the National “Ninth-Five-Year Plan” Special Project (No.97-926-04-03) and “KZ95T-04-04-04” Fund.     

Concentrations and Distribution of Trace Metals of PM_(10) and TSP Particles Collected in the Qingdao Area

Aerosol samples of PM10 (particulate matter with aerodynamic diameters less than 10μm) and TSP (total suspended particles) were simultaneously collected from April 2001 to March 2002 at the top of Mount Baguan on the downtown campus of Ocean University of China, Qingdao, China. The concentrations of Al, Fe, Mn, Cu, Pb and Zn were determined by means of inductively coupled plasma atomic emission spectrometry (ICP-AES). The monthly variability of the mass concentrations of aerosol particles and the concentrations of trace metals are presented and discussed. The distribution pattern of these metals in PM10 and TSP is also discussed. During the observation period, the mass concentration of PM10 at this site ranged from 13.80 to 306.42μgm-3 , while that of TSP ranged from 31.02 to 568.82μgm-3. Both PM10 and TSP reached their highest concentrations in springtime, while the lowest values occurred in summertime. The concentrations of crustal metals followed the same variation pattern, while those of anthropo