The sources and composition of organic matter in sediments of the Jiaozhou Bay：implications for environmental changes on a centennial time scale

The Jiaozhou Bay is characterized by heavy eutrophication that is associated with intensive anthropogenic activities. Four core sediments from the Jiaozhou Bay are analyzed using bulk technologies, including sedimentary total organic carbon（TOC）, total nitrogen（TN）, the stable carbon（δ13C） and nitrogen（δ15 N） isotopic composition to obtain the comprehensive understanding of the source and composition of sedimentary organic matter and further shed light on the environmental changes of the Jiaozhou Bay on a centennial time scale.Results suggest that the TOC and TN concentrations increase in the upper core, having indicated a probable eutrophication process since the 1920 s in the inner bay and the 2000 s in the bay mouth. The TOC and TN concentrations outside the bay have also changed since 1916 owing to the variation of terrigenous input.Considering TOC/TN ratio, δ13 C and δ15 N, it can be concluded there is a mixture of terrigenous and marine organic matter sources in the study area. A simple two end-member（terrigenous and marine） mixing model usingδ13 C indicats that 45%–79% of TOC in the Jiaozhou Bay is from the marine source. The environmental changes of the Jiaozhou Bay are recorded by geochemical proxies, which are influenced by the intensive anthropogenic activities（e.g., extensive use of fertilizers, and discharge of sewage） and climate changes（e.g., rainfall）.

Organic Geochemistry of Sedimentary Rock-hosted Disseminated Gold Deposits in Southwestern Guizhou Province, China

Sedimentary rock-hosted disseminated gold (SRHDG) deposits in the Youjiang-Nanpanjiang Basin, southwestern Guizhou Province are commonly hosted by the same fold crests that commonly contain a remarkable amount of organic material. The total organic carbon (TOC) contents of the ores and host rocks are usually less than 1%. The reflectance of vitrinite and pyrobitumen in the ores and the host rocks ranges from 1.5% to 4.5%, often in the range of 2% to 3%. In the Lannigou deposit, the reflectance of vitrinite and pyrobitumen in the ores is usually somewhat higher than those within the host rocks, indicating a hydrothermal impact on the organic matter in the altered host rocks. On the contrary, the estimated maximum paleotemperatures of the Getang and Zimudang deposits are higher than the homogenization temperatures of the fluid inclusions in the ores, signifying that the organic matter maturation predated Au mineralization. No correlation between the organic matter contents and Au concentrations were recognized in the ores. However, the most striking observation is that there is a positive correlation between the S2 (a parameter of Rock-Eval analysis), Au and As contents of the ores in the Lannigou deposit. Organic matter maturation and migration is apparent from the TOC vs. HCI diagram. Furthermore, group analysis of the dichloromethane extractable organic component of the ores and host rocks shows that the maturation degree of the organic matter in the ores is slightly higher than that of the host rocks in the Lannigou gold deposit. However, the compositions of their alkanes, steranes and terpenes, which serve as biomarkers, are quite similar; this suggests that the organic matter found in the ores and host rocks has a common marine source. Organic matter probably contributed to the preconcentration of Au in the host rocks. Hydrocarbons in the system, on the other hand, clearly contributed to the emplacement of the gold mineralization through thermal sulfate reduction. Organic matter in the solution might have increased the potential of the hydrothermal solution to transport Au.

Hydrocarbon Generation Potential and Organic Matter Enrichment Mechanism of the Cambrian Marine Shale in the Tadong Low Uplift,Tarim Basin

Cambrian shales in China and elsewhere contain abundant oil and gas resources.However,due to its deep burial and limited outcrop,there has been relatively little research conducted on it.The Cambrian shale of the Tadong low uplift in the Tarim Basin of western China,specifically the Xidashan-Xishanbulake Formation(Fm.)and overlying Moheershan Fm.provide a case study through the use of organic petrology,mineralogy,organic and elemental geochemistry,with the aim of analyzing and exploring the hydrocarbon generation potential(PG)and organic matter(OM)enrichment mechanisms within these shale formations.The results indicate that:(1)the Cambrian shale of the Tadong low uplift exhibits relatively dispersed OM that consists of vitrinite-like macerals and solid bitumen.These formations have a higher content of quartz and are primarily composed of silica-based lithology;(2)shale samples from the Xidashan-Xishanbulake and Moheershan formations demonstrate high total organic carbon(TOC)and low pyrolytic hydrocarbon content(S_(2))content.The OM is predominantly typeⅠand typeⅡkerogens,indicating a high level of maturation in the wet gas period.These shales have undergone extensive hydrocarbon generation,showing characteristics of relatively poor PG;(3)the sedimentary environments of the Xidashan-Xishanbulake and Moheershan formations in the Tadong low uplift are similar.They were deposited in warm and humid climatic conditions,in oxygen-deficient environments,with stable terrigenous inputs,high paleoproductivity,high paleosalinity,weak water-holding capacity,and no significant hydrothermal activity;and(4)the relationship between TOC and the paleoproductivity parameter(P/Ti)is most significant in the Lower Cambrian Xidashan-Xishanbulake Fm.,whereas correlation with other indicators is not evident.This suggests a productivity-driven OM enrichment model,where input of landderived material was relatively small during the Middle Cambrian,and the ancient water exhibited lower salinity.A comprehensive pattern was formed under the combined control of paleoproductivity and preservation conditions.This study provides valuable guidance for oil and gas exploration in the Tarim Basin.

Assessment of metal pollution in the Anzali Wetland sediments using chemical partitioning method and pollution indices

Metal pollution in aquatic ecosystems is of immense importance. Under various environment circumstances, the metal contents of sediments can enter into the overlying water body leading to severe toxicity. This study aims to determine metal concentrations in sediments of Anzali International Wetland in Iran. Chemical partitioning method is used to determine the portion of anthropogenic pollution and the mobility potential of each metal. The intensity of metal pollution in sediments of the wetland is assessed using three reliable indices. The results of chemical partitioning reveal that cadmium bear the highest risk of being released into the aquatic environment and high amount of manganese in sulfide bond phase implies the initiation of redox state in aquatic environment of the Anzali Wetland. The results of chemical partitioning studies show that Pb, Cd, Mn and As have the highest anthropogenic portion. Cluster analysis also confirms the results of chemical partitioning and indicates that the mentioned metals can be originated from anthropogenic sources. Sediment pollution indices, including, Igeo,IPOLL, and m-ERM-Q reveal that metals are in the range of low to moderate pollution and also show that the highest metal pollution is in the eastern and central parts of the wetland. This can be ascribed to rivers which are the recipient of industrial, agricultural and municipal wastewaters and flow into these parts of the wetland.

Geochemical records of the sediments and their significance in Dongping Lake Area,the lower reach of Yellow River,North China

Dongping Lake area,located in the lower reaches of Yellow River,is an ideal place to study the changes of modern river and lake sedimentary environment.The sediment samples of Dawen River,Yellow River,and Dongping Lake were collected,and the major elements,trace elements and organic matter geochemical composition of the samples were analyzed.Cluster analysis,characteristic element ratio method and graphic method were used to explore the geochemical characteristics of sediments and their environmental implication.The results show that the contents of SiO_(2),Na_(2)O,TiO_(2) and Zr in sediments of Dawen River and Yellow River are relatively high,and the contents of iron and manganese oxides,organic matter,CaO,P2O5 and Sr in lake sediments are relatively high.That reveals the differences of sedimentary environments between the rivers and the lake.The contents of Sr and Zr in Dawen River are affected by the rapid migration of clastic materials in the upstream carbonate source area during the flood season;the δCe,ΣREE and REE’s ratios in the sediments of the Yellow River reflect the influence of the Loess source;and the distribution of elements changes along the flow direction during the flood season.The characteristics of pH,element composition and LREE&HREE fractionation of the lake sediments indicate that the sediment source is complex,and the lake environment is affected by the flood season.The study shows that the geochemical content and its variation characteristics of sediments effectively reveal the sedimentary environment,material composition and characteristics of flood season of rivers and the lake in the study area.

Sedimentary and Geochemical Aspects of a Refinery Impacted Coastal Area: A Case Study of the Todos os Santos Bay (Bahia, Brazil)

The present study was performed in the northeast portion of the Todosos Santos Bay, Bahia State, Brazil, an area under influence of the Landulpho Alves-Mataripe (RLAM) refinery effluents. The aim of this work is to evaluate the modern sedimentary processes based on grain-size analysis, calcium carbonate and sedimentary organic matter concentration and behavior considering the possible effects of the petroleum industry’s refining on these sediments. The concentrations and variations of the three main constituents of organic matter (total organic C, total N and organic P), and the resulting elemental ratios (C/N, C/P and N/P), were studied on a seasonal spatial and temporal scale (winter 2004 and summer 2005), therefore subsidizing the environmental analysis, especially in regards to the benthic ecosystem. Fifty samples from twenty-five sampling stations were collected with a grab sampler. Well sorted sandy sediments are observed in coastal sampling stations and in the Caboto channel. The recent deposition of fine sediments was observed especially in the west and central portions of study area. However, these spots contain the highest percentages of organic material, which do not present significant seasonal and spatial variations, revealed by the values of total organic C which reach values of up to 3.1%, total N (0.01% to 0.15%) and the organic P contents that reach a maximum of 15.9 μmol·g-1. In general, the elemental ratios indicated continental organic matter inputs, probably derived from human activities.

厦门杏林湾水库底泥有机质和营养盐的分布特征与来源及污染评价

以厦门杏林湾水库为研究对象,测定表层底泥中有机质(OM)、总氮(TN)、游离态氮(FN)、可交换态氮(EN)、酸解态氮(HN)、残渣态氮(RN)、总磷(TP)、有机磷(OP)、无机磷(IP)、铁铝结合态磷(NaOH-P)和钙结合态磷(HCl-P)的质量比,分析表层底泥中有机质及营养盐的分布特征和污染状况。结果表明:杏林湾水库底泥中OM,TN和TP的平均质量比分别为49360.28,1588.63,1095.63 mg·kg^(-1);OM,TN,EN和HN的空间分布呈现从后溪汇入处至入海口处先增加后减小、从九天湖排洪渠和董任排洪渠交汇处至入海口处逐渐减小的特征;TP,IP,NaOH-P和HCl-P的空间分布呈现随水流方向逐渐减小的特征;底泥具有较高氮磷释放风险,易发生富营养化问题,其中,氮主要来源于有机质富集,磷主要来源于上游支流及周边地区含磷农业废水和居民生活污水,OM主要来源于高等植物;氮、磷单项污染指数和综合污染指数整体上均处于重度污染,营养盐污染主要来源于氮,有机指数整体处于尚清洁水平,且底泥整体受到有机氮污染。

西凉湖沉积物重金属及营养元素分布特征及污染评价

以西凉湖沉积物为研究对象,利用地累积指数法和潜在生态风险指数法评估其重金属元素的污染情况,利用综合污染指数法和有机污染指数法评价其氮、磷元素及有机质的污染情况。结果表明,西凉湖沉积物整体受到重金属污染水平较低,Cu、Zn、As、Hg污染情况在空间分布上相似,少数点位Cd、Ni、Hg元素达中度或重度污染,归因于养殖饲料和交通运输。西凉湖沉积物中氮、磷元素污染评价结果显示,磷元素污染情况相对较轻,80%的点位处于中度污染水平;氮元素污染情况严重,所有点位均达重度污染;氮、磷元素的综合评价中所有点位均达重度污染。有机污染指数法评价结果显示,所有点位有机污染指数均大于0.50,达重度污染水平。结合氮、磷元素的评价结果,将外源污染归因于西凉湖曾经过度发展渔业造成的营养输入。

千岛湖沉积物中碳、氮、磷的分布特征及污染评价

通过测定千岛湖柱状沉积物中有机质(OM)、总氮(TN)和总磷(TP)含量,分析其污染分布特征,并评价污染水平。结果表明,千岛湖沉积物中OM、TN、TP平均值分别为1.44%、1.86 mg/g、0.89 mg/g。空间分布差异明显,城区库湾、新安江干流沿线污染相对较重;垂直分布,OM、TN、TP整体上均从湖底由下而上呈逐步上升变化过程。相关性分析表明,该湖沉积物中OM、TN、TP具有较高的同源性,氮、磷多以有机形式存在。C/N值表明,该湖沉积物中有机质主要来自内源的水生生物分解。评价结果显示,综合污染指数范围为1.1~4.2,该湖整体上处于重度污染水平,TP污染重于TN;有机指数范围为0.04~0.52,整体上属于轻度污染水平。

牛栏江沉积物氮磷和有机质时空分布及污染评价

沉积物中的氮磷释放严重影响河流水质,为揭示牛栏江沉积物中氮磷及有机质的时空分布特征及污染风险,测定了牛栏江23个样点的沉积物总氮(TN)、总磷(TP)及有机质(OM)含量,分析其时空分布,并运用污染指数法评估了污染现状。结果表明:①牛栏江干流表层沉积物中TN、TP和OM均值分别为0.20,1.58,65.45 g/kg,支流均值分别为0.39,1.77,86.39 g/kg,呈现一定的空间异质性,但不受水期影响。②牛栏江表层沉积物OM与TN、TP呈正相关(P<0.05),具有一定的同源性,但TN与TP在来源及沉积行为上有一定差异。③总体评价显示,牛栏江沉积物受到轻度有机污染和重度综合污染,其中74%的样点TP含量达到重度污染,且集中于支流,这可能与人类活动导致的外源污染输入有关。研究成果可为牛栏江水环境防治提供科学依据。

污泥基生物炭的制备及其在环境污染治理中的应用

随着我国水处理厂普及率逐渐上升,剩余污泥产量增长迅速,且因其危害性高、难处理的特点,在环境污染治理中备受关注。污泥基生物炭是以污泥为原料通过热解方式制得的固体产物,因其良好的吸附和催化性能被广泛应用于环境介质中各类污染物的去除。本文对污泥基生物炭的制备方法、热解温度对其理化性能的影响及其改性处理的研究进展进行了综述,并对其催化机理研究、回收再利用和应用于土壤污染治理的前景作出了展望。

天然有机质及其在地表环境中的重要性

天然有机质是地表各种环境介质中的重要化学组分,分布广泛.越来越多的研究已经表明:它在地表生态系统的物理、化学和生物过程中都起着十分重要的作用;它与生态系统的各个重要环节密切相关,是生态系统中能量与物质循环的重要途径.因此,天然有机质不仅是生物地球化学、生态学和环境科学等研究领域的重要内容之一,而且也是环境污染的评价、预测和治理研究中的基础理论问题,是目前环境质量、毒理学、环境立法和管理研究共同关注的科学问题.本文主要以陆地地表淡水湖泊与河流水环境为例,对天然有机质的来源、化学结构、循环特征,与养分循环的耦合关系,对有毒金属元素和有机污染物迁移转化和毒性影响机理等几个方面的研究进展进行了简要的总结;针对我国水体富营养化和环境污染等重要环境问题,阐述当前应该采取的研究思路和存在的主要科学内容,并对现代有机环境与生物地球化学学科的研究趋势进行了展望.

沉积物中有机质的环境行为研究进展

水体沉积物是重金属、有毒有机化合物等环境污染物及C、N、P等营养元素的汇和释放源 ,而有机质对这些污染物和营养元素在沉积物中的迁移、转化等地球化学行为中起着至关重要的作用 .本文就近期有关沉积物中有机质的环境地球化学行为方面的研究进行了综述 ,重点评述了有关沉积物中有机质本身的来源、性质、迁移和矿化及其环境效应等方面的研究进展 .

溶解性有机质对土壤中有机污染物环境行为的影响

土壤中溶解性有机质 (DOM)是生物活性和物理化学反应活性都很活跃的有机组分 ,主要通过疏水吸附、分配、氢键、电荷转移、共价键、范德华力等多种作用与有机污染物结合 ,提高溶液中有机污染物的溶解度 ,改变土壤中有机污染物的吸附 解吸、迁移 转化等环境行为 .DOM对有机污染物的吸附 解吸、迁移 转化过程的影响有双重性 :一方面 ,DOM与有机污染物在土壤表面的共吸附可增加土壤对有机污染物的吸附容量 ,促进有机污染物在土壤中的吸持 ;另一方面 ,DOM对有机污染物的增溶作用 ,有利于土壤中有机污染物的解吸 ,提高移动性 .作为光敏剂 ,DOM能提高土壤中有机物的光解反应速率 .在一定条件下 ,DOM也可影响土壤中有机污染物的水解过程 .

土壤中溶解性有机质的环境特性与行为

本文就土壤中溶解性有机质 (DOM)的吸附 解吸特性、迁移 转化特性及其影响因素、DOM对重金属吸附 解吸及生物毒性的影响、DOM对农药等有机污染物吸附 解吸及生物可降解性的影响进行了评述 .同时 。

陆地生态系统中水溶性有机质的环境效应

目前水溶性有机质 ( Dissolved Organic Matter)已逐步成为陆地生态系统中的一个研究热点。系统地评述了陆地生态系统中 DOM的组成特点及其环境效应。尽管关于陆地生态系统中 DOM的研究还不完善 ,至今对其性质、组成和分类方法等问题看法不一 ,但现有结果已经表明 DOM是一种十分活跃的重要化学组分 ,它对陆地生态系统中污染物质的溶解、吸附、解吸、吸收、迁移和生物毒性、微生物活动以及土壤形成过程等均有显著的影响。影响 DOM在陆地生态系统中的环境效应的主要因素包括 :DOM与污染物的络合作用、污染物溶解 /沉淀作用、土壤对 DOM的吸附作用、土壤质地、酸碱缓冲作用等。

武汉城市湖泊汞的环境地球化学评价

汞由于其在环境中的持久性、生物地球化学可循环性以及潜在的生态威胁性而受到格外关注。对武汉远郊、城乡结合部和市区三种环境中6个湖泊的水、沉积物和生物(鱼)中汞污染特征进行了调查采样,用原子荧光光谱仪进行了汞含量的测定。采用Hakanson提出的潜在生态危害指数法直接评价了武汉湖泊汞的生态效应。结果表明,与国家食品卫生标准鱼肉中汞含量(≤300ng/g)相比,除梁子湖乌鱼(汞含量为676ng/g)外,6个湖泊3种鱼肉中汞含量均未超标,表明武汉城市湖泊汞元素尚未造成明显的生态效应;与国家Ⅲ类水质汞含量标准(0.1μg/L)相比,除金银湖水汞含量(0.137μg/L)略有超标外,其他湖水汞含量分布在0.048～0.081μg/L之间,均在合格标准线以下,武汉地区湖水中重金属汞污染不严重,不会构成严重的环境问题;应用Hakanson评价模型,据单个金属的潜在生态危害系数,排出所研究湖泊沉积物汞污染程度的序列为:东湖>墨水湖>金银湖>梁子湖>汤逊湖>鲁湖。

那什那泡沉积物氮磷有机质污染特征及评价

于2010年7月在那什那泡采集柱状沉积物样品，测定了那什那泡沉积岩芯（NSN）总氮（TN）、总磷（TPl以及有机质（OM）等指标的含量，分析了TN、TP、OM、TOC／TN的垂直分布特征。研究结果表明：NSN中TN含量变化范围为1156-4191mg／kg，平均为2891mg／kg；TP含量变化范围为358-509mg／kg，平均值为442mg／kg；OM含量变化范围为1．29％-3．64％，平均值为2．03％。沉积物中OM含量变化幅度不大，TN和TP波动明显，但三者含量从底层至表层大体上都呈上升趋势。TOC／TN为2．50～7．94，平均值为4．35，沉积物中有机质主要来自湖泊内源的水生生物、浮游动植物和藻类。通过有机指数与有机氮指标评价表明那什那泡2001～2009年存在有机污染；从有机氮指标来看，所采的柱状沉积物在整个沉积过程中有机氮含量都很高，那什那泡存在有机氮污染。

湖泊沉积有机碳同位素与环境变化的研究进展

湖泊沉积有机质稳定碳同位素 (δ13Corg)在区域气候与环境变化方面的应用研究近年来发展迅速 ,成果令人瞩目 .保存在各类湖泊岩芯中的δ13Corg记录揭示了晚更新世以来大气CO2浓度的变化、湖泊水位波动、湖区生态与植被的变迁以及气温变化等重要环境信息 .由于造成δ13Corg值变化的影响因素较多 ,确定个湖与环境变化有关的主导因素时常有赖于其它证据的帮助 ,诸如地球化学、古湖沼学、孢粉学、分子同位素地层学等等 .前人通过研究来自不同类型湖泊、具不同曲线形态特征的δ13Corg记录 ,提出了多种环境解释模型 .本文对此作了归纳和评述 .鉴别和澄清湖泊沉积有机质的源物质以及有机物源随环境变化而发生过的变动 ,是研究δ13Corg记录环境意义至关重要的基础性工作 .由于有机质含量、碳氮比值、氢指数、生物残留物鉴别等常能提供有关湖泊有机质来源、产率、成岩作用等方面的有用信息 ,这方面的研究结果应该尽可能一并提供 ,以利于恰当地应用现有的环境解释模型 ,或者建立个湖新模型 .单体生物标志化合物鉴别通常也能为区分湖积有机质中陆生、水生、细菌生等不同碳的来源提供有用信息 .特定化合物同位素分析技术近年来成功地应用于建立单体生物标志化合物碳同位素地层学 ,为湖积有机碳同位素在生态环境演变?

南黄海北部表层沉积物中生物标志物的组成特征及其地球化学意义

通过对南黄海北部14个站位的19个表层沉积物样品进行了粒度、有机碳、GC-FID和GC-MS-MS测定,探讨沉积物有机质中生物标志物组成特征及地球化学意义。研究区表明,沉积物有机碳含量较高,正构烷烃呈双峰分布,具有明显奇偶优势、平均L/H为0.36,说明沉积物中陆源高等植物贡献占优,分析对比表明其沉积物可能主要来自古黄河输入。类异戊二烯烃Pr/Ph均值0.46,表明有机质沉积于强还原环境;Pr/C_(17)和Ph/C_(18)值均小于1,并且随深度有减小的趋势,反映了研究区微生物的降解作用。甾类化合物C_(29)豆甾烷>C_((?))胆甾烷>C_(28)麦角甾烷,说明萜类化合物和甾类化合物主要为陆相输入。较高OEP值、高丰度的藿烯和莫烷及甾烷S构型含量均反映了现代沉积物中有机质未熟-低熟特征,但由于原始母质影响和微生物发育,Ts/Tm和C_(31)αβS/(S+R)、C_(32)αβS/(S+R)、C_(33)αβS/(S+R)和C_(29)αββ/(ααα+αββ)值较高。