Distribution and speciation of mercury in the Hongfeng Reservoir,Guizhou Province,China

The water, pore water, sediment, and fish samples were collected from the Hongfeng Reservoir in November 2003 and February 2004 in accordance with trace metal protocols. The average concentrations of total mercury （THg）, dissolved mercury （DHg）, reactive mercury, dissolved gaseous mercury, total methylmercury, and dissolved methylmercury in the water columns were 8.00, 5.70, 0.63, 0.05, 0.16, and 0.07 ng/L, respectively. THg and DHg in the water columns, THg in pore water and THg in lake sediments of the Hongfeng Reservoir showed the level of mercury in the Hongfeng Reservoir was higher than in other natural waters in the world due to the loading of a lot of waste water with relatively high concentrations of mercury, whereas methylmercury concentrations in fish （wet weight） varied from 1.73-51.00 ng/g, much lower than in most remote lakes and reservoirs reported in northern Europe and North America. Methylmercury distributions in pore water and sediments showed methylation occurred mainly in the upper several centimeters of sediment cores in the Hongfeng Reservoir. The concentrations of dissolved organic carbon, total suspended particles, total Hg, and methylmercury were higher at Houwu than those at Daba in November 2003. It is suggested that other pollutants such as N and P from fishing farm and other waste water at Houwu, which resulted in deterioration of water quality, affected the concentrations and distributions of mercury species in the reservoir.     

夏季红枫湖地区农田土壤-大气界面汞交换通量的初步研究

采用动力学通量箱法(Dynamic Flux Chamber)与高时间分辨率大气测汞仪联用技术对贵州红枫湖地区土壤-大气界面间汞交换通量进行了初步研究.结果显示,红枫湖地区土壤-大气界面间汞交换通量变化范围为-8.6 ng～215.3 ng@m-2@h-1,平均27.4士40.1 ng/m2@h(n=255);且土壤与大气界面间的汞交换是双向的既有土壤汞的释放,又有大气汞的沉降,主要以土壤汞的释放为主(n释放=253,n沉降=2n).土壤汞的释放通量与土壤温度、气温、光照强度有强相关关系,相关系数分别为0.80、0.83、0.74.     

Methylmercury and total mercury distribution in the sediments of Baihua Reservoir, Guizhou Province, China

Mercury is an important pollutant in lakes. Methylmercury （MeHg）, the most toxic mercury species, which can be formed from inorganic mercury in lakes, can be bioaccumulated into high concentration in food chain and result in a potential threat to human beings. Sediments play an important role for the Hg biogeochemistry in the aquatic systems： Mercury methylation has been shown to be fastest in the surfacial sediments, where the microbial activity is highest. The formation of MeHg in lakes suggests that sediments and/or near-shore wetlands can be the sources of MeHg in aquatic environments. The Baihua Reservoir, located in the suburb of Guiyang, was impounded in 1966. From the 1970s to the 1990s, Guizhou Organic Chemical Plant which used inorganic mercury as catalyst to produce acetic acid, was responsible for the discharge of waste water with high mercury content.     

Spatial and temporal distributions of mercury species and controlling factors in Hongfeng Reservoir, Guizhou, China

The Hongfeng Reservoir was built in 1960 and is an alkaline, hyper-eutrophic and seasonal anoxic reservoir due to the contamination from domestic and industrial wastewaters. The water samples at deferent depths from two sampling sites were collected from November 2003 to September 2004 using metal clean protocols. Total Hg （THg）, reactive Hg （RHg）, dissolved total Hg （DHg）, dissolved gaseous mercury （DGM） were measured by gold trap pre-concentration and CVAFS detection. Methyl mercury was measured by distillation followed by aqueous phase ethylation, precollection on a Tenax, isothermal gas chromatography and cold vapor atomic fluorescence detection. There was no discernible seasonal trend （about 8 ng/L） in THg concentration based on the average information developed during the four cruises except for high concentrations at bottom and water-sediment interface in May and September 2004. On the other hand, particulate mercury （PHg） and methyl mercury have discernible seasonal variability. Proportion of PHg increased from 29% in February 2004 to 50% in May 2004. In November 2003, February and May 2004 methyl mercury concentrations were relative low and increased with depth （from 0.13 to 0.40 ng/L）. In September 2004, methyl mercury concentrations increased from 0.14 ng/L in the epilimnion to 0.99 ng/L in the hypolimnion. DGM concentrations varied from 0.024 to 0.11 ng/L and decreased with depth.     

Enzymatic and Microbial Degradation of Organic Matter in Lake Hongfeng, Guizhou Province, China

1IntroductionEnzymaticandmicrobialdegradationoforganicmatterhasabearingnotonlyonearlydiagene sis,butalsoonelementcyclingandmicrobedistributioninlakesediments.Somereportsshowedtheabundancevariationsoforganicmatterinsediments (BurdigeandGardner,1998;ArthurandDean ,1998;WanGuojiangetal.,2 0 0 0 ) .However,duetothecomplexchemicalcompositionoforganicmatter,mechanismsofenzymaticandmicrobialdegradationandvariationsofeachchemicalcomponentneedtobestudiedfurther.Underanoxiccondition ,SO2 -4 isanimpo…     

PCBs and PAHs in surficial sediments from aquatic environments of Mexico City and the coastal states of Sonora,Sinaloa, Oaxaca and Veracruz (Mexico)

Concentrations of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were measured in 13 surficial sediment samples collected at three lacustrine locations in the surroundings of Mexico City and four coastal areas of the States of Sinaloa, Sonora, Oaxaca and Veracruz. Total PCB concentrations span the interval 3.18–621 ng g⁻¹. The highest values (63.7–621 ng g⁻¹) were found in Mexico City, which is a highly anthropogenically impacted area, whereas low concentrations (3.18–12.9 ng g⁻¹) were characteristic of seven places, some of them subject to intense hydrodynamics. In these latter cases, values increase by 18–73 times if normalised against the fine fraction (silt plus clay) content in sediment. Two samples from Mexico City exceed the ERM (Effect Range Median) guidelines and are likely to cause adverse effects. Samples contain only lower chlorinated PCBs (mainly 2-, 3- and 4-CB), thus suggesting that the most used PCB commercial mixture was Aroclor 1242. The homologue composition of the sample taken close to the nuclear power plant of Laguna Verde is identical to this commercial mixture. PAHs in the same samples have relatively low concentrations (14.9–287 ng g⁻¹), well below ERL (Effect Range Low) guidelines. The composition of PAH mixtures accounts for the influence of both petrogenic and pyrolitic sources, with these latter prevailing at some places in Mexico City.     

贵州省普定水库水体及沉积物孔隙水中汞的含量和形态分布初步研究

为了弄清楚普定水库汞的地球化学循环特征,用金汞齐-冷原子荧光光谱法(CVAFS)和气相色谱技术(GC), 研究了乌江流域上游普定水库水体剖面和沉积物间隙水剖面汞的赋存形态(总汞 THg)、溶解态汞(DHg)、活性汞(RHg)、颗粒态汞(PHg)、总甲基汞(TMeHg)、溶解态甲基汞(DMeHg)和颗粒态甲基汞(PMeHg)的分布特征.结果显示,普定水库水体总汞浓度为1.29～3.18 ng/L, 活性汞浓度为0.09～0.43 ng/L, 总甲基汞浓度为0.06～0.18 ng/L.沉积物间隙水中溶解态汞浓度为2.65 ～11.47 ng/L, 溶解态甲基汞浓度为0.06 ～1.16 ng/L.实验数据表明,普定水库水体中溶解态汞和颗粒态含量相当,其中颗粒态汞占总汞的比例为46%,并与总汞存在极显著相关性(R=0.929,n=20,P＜0.01),溶解态汞与总汞相关性不明显(R=-0.067,n=20);冬季普定水库甲基汞以溶解态甲基汞为主,溶解态甲基汞占总甲基汞的比例为63%,溶解态甲基汞与总甲基汞无明显相关关系(R=0.292,n=20),颗粒态甲基汞与总甲基汞存在极显著的相关性(R=0.815,n=20,P＜0.01).试验数据表明沉积物孔隙水溶解态汞与溶解态甲基汞浓度明显高于上覆水体, 是普定水库水体中汞的一个重要来源.     

Discovery and Analysis of Shale Gas in a Carboniferous Reservoir and its Enrichment Characteristics in the Northern Nanpanjiang Depression,Guizhou Province,China

Shale gas resources are considered to be extremely abundant in southern China, which has dedicated considerable attention to shale gas exploration in recent years. Exploration of shale gas has considerably progressed and several breakthroughs have been made in China. However, shale gas explorations are still scarce. Summary and detailed analysis studies on black shale reservoirs are still to be performed for many areas. This lack of information slows the progress of shale gas explorations and results in low quantities of stored black shale. The Carboniferous Dawuba Formation, which is widely distributed and considerably thick, is one of the black shale formations targeted for shale gas exploration in southern China in the recent years. The acquisition and analysis of total organic carbon, vitrinite reflectance,types of organic matter, mineral composition, porosity, and permeability are basic but important processes. In addition, we analyzed the microscopic pores present in the shale. This study also showesd the good gas content of the Dawuba Formation, as well as the geological factors affecting its gas content and other characteristics. To understand the prospect of exploration, we compared this with other shale reservoirs which have been already successfully explored for gas. Our comparison showesd that those shale reservoirs have similar but not identical geological characteristics.     

Seasonal distribution of total mercury and methylmercury in sediments of the Wujiangdu Reservoir, Guizhou, China

The concentrations of total mercury and methylmercury in sediments were determined at the dam of the Wujiangdu Reservoir in different seasons. Total mercury (HgT) levels in the whole sediment profile were 254.2±47.0 ng/g in winter, 254.2±31.6 ng/g in spring, and 256.7±60.8 ng/g in summer, without significant variations in different seasons or at different depths. In contrast, the methylmercury (MeHg) compounds were most abundant at the sediment-water interface and decreased progressively with depth. MeHg contents of the sediments during different seasons are highly dependent on microbial activity, and seem to be higher when Hg (II)-methylating microorganisms are active. Thus, MeHg levels tend to rise in the loci where nutrient supplies and biological productivity are favorable. The percentage of HgT that is present as MeHg in the sediments increased gradually from December 2003 to April 2004 and to July 2004.     

Phosphorus fractions and bioavailability in relation to particle size characteristics in sediments from Lake Hongfeng, Southwest China

Information on the chemical composition of phosphorus (P) fractions in sediments is fundamental to understanding P bioavailability and eutrophication in lake ecosystems. Phosphorus fractions and its bioavailability in sediments cores of Lake Hongfeng, southwest China, were investigated using a chemical sequential extraction scheme. Relationships between P fractions, P bioavailability and particle sizes were discussed. P fractions concentrations were ranked in the order: Residual-P > NaOH–rP > NaOH–NRP > HCl–P > BD–P > NH₄Cl–P, and all of them decreased with increasing sediment depth. Statistical analysis showed that concentrations of bioavailable P (BAP) which includes the NH₄Cl–P, BD–P, NaOH–rP and NaOH–NRP fractions ranged from 404.68 to 1,591.99 mg/kg and accounted for 26.8–71.8 % of the concentrations of total phosphorus (TP) in the top 5 cm sediments, whereas in the whole sediment cores, their concentrations ranged from 239.70 to 1,591.99 mg/kg and accounted for 26.8–76.0 % of TP. The results suggested that the sediments were a large potential source of P for algae blooms in Lake Hongfeng. Phosphorus fractions and their potential bioavailability were influenced by the sediment particle sizes, especially the bioavailability of the NH₄Cl–P fraction, which was strongly affected by the presence of fine particle sizes in the sediments.     

Re–Os Dating of Bitumen from Paleo–Oil Reservoir in the Qinglong Antimony Deposit, Guizhou Province, China and Its Geological Significance

Abundant organic inclusions are present in the Qinglong antimony deposit. However, the source rocks of these organic matters have not been reliably identified. Recently, a paleo–oil reservoir was found in the Qinglong antimony deposit. In view of similar components of gaseous hydrocarbon, we propose that the organic matters observed in inclusions in Qinglong antimony deposit would come from this paleo–oil reservoir. We used the Re–Os dating method to determine the age of the bitumen from this paleo–oil reservoir, and obtained an isochron age of 254.3±2.8 Ma. The age indicates that the oilgeneration from source rock occurred in the early Late Permian, earlier than the Sb mineralization age(~148±8.5 Ma) in the Qinglong antimony deposit area. After oil generation from Devonian source rock, first and secondary migration, the crude oil have probably entered into the fractures and pores of volcanic rocks and limestone and formed a paleo–oil reservoir in the western wing of Dachang anticline. As burial process deepened, the crude oil has turned into natural gas, migrates into the core of Dachang anticline and formed a paleo–gas reservoir. The hydrocarbons(including CH_4) in the reservoirs can serve as reducing agent to provide the sulfur required for Sb mineralization through thermal chemical reduction of sulfates. Therefore, the formation of oil–gas in the area is a prerequisite for the Sb mineralization in the Qinglong antimony deposit.     

贵州织金煤层气非储层水平井开发技术研究

直井开发煤层气钻井和压裂成本高,控制面积小,单井产气量低;煤层内水平井钻进难度大,风险高,薄煤层中井眼轨迹控制难度大,钻井液有害固相对储层伤害严重,采收率低。基于此,分析贵州织金区块煤系地质构造,提出在煤系地层内稳定的非储层内布水平井,通过压裂造缝沟通水平井上下煤层同时开发多层煤层的新思路。与常规开发方式相比,非储层内水平井具有钻井风险小、储层伤害小、单井产量高的优点,同时还可以开发煤系致密气和页岩气,提高非常规天然气利用率。研究非储层内水平井开发贵州织金煤层气技术,为解决贵州煤系地层煤层多而薄、层间距小等特性煤层气开发难题以及综合利用煤系气提供新的方式。     

Ammonia adsorption and nitritation in sediments derived from the Three Gorges Reservoir,China

The influences of suspended particles (SPs) on NH₄ ⁺ adsorption and nitritation occurring in the water system of the Three Gorges Reservoir (TGR) were evaluated in this study. The results indicated that the adsorption of NH₄ ⁺ was significantly affected by the SPs concentration under the conditions typically present in the TGR. The amount of ammonia adsorbed per unit weight of suspended particles was inverse proportional to the concentration of suspended particles. However, the influences of the particle size and the organic matter concentration existing in SPs were insignificant under the experimental conditions. The effects of suspended particles on nitritation were determined by the use of ammonia-oxidizing bacteria (AOB) strain SW16, identified as Nitrosomonas nitrosa, which was isolated from sediment samples of the TGR. Suspended particle concentration in water–sediment solution played an important role in the nitritation process. The rate of nitritation enhanced with the increase of the suspended particle concentration. It was found that the critical factor controlling ammonia oxidizing rate was the AOB biomass resulting from the AOB growth rate. Moreover, results demonstrated that both particle size and organic matter content showed little effect on the nitritation process under the experimental conditions.     

贵州晴隆锑矿古油藏沥青稀土元素地球化学特征及意义

晴隆锑矿沙子岭火山岩型古油藏的发现,对晴隆锑矿床的成因研究乃至于金属矿和油气勘探均具有重要意义。本文分析了晴隆锑矿古油藏沥青的稀土元素地球化学特征,并将沥青与锑矿及围岩、区域烃源岩的稀土元素作对比分析,探讨古油藏与锑矿成矿关系。结果表明:古油藏中沥青稀土元素ΣREE低,轻重稀土分馏明显,Eu和Ce整体无明显异常,稀土配分属轻稀土富集右倾模式;沥青与锑矿及围岩稀土元素地球化学特征差异较大,二者在稀土质量分数、Ce异常以及配分模式均有明显差异,判定古油藏与锑矿成矿物质和成矿流体来源不同。结合流体包裹体和同位素测试等资料,通过对比沥青与区域烃源岩稀土元素特征,我们认为晴隆锑矿古油藏沥青与泥盆系泥质烃源岩有成因关系;古油藏在演化过程中提供了烃类气体(CH_4),使SO_4~(2-)还原出S~(2-)而参与成矿作用,形成辉锑矿。     

贵州赤水宝元构造三叠系嘉二1-嘉-气藏储层特征

三叠系嘉二1-嘉-层是赤水气田的主要产层之一．探讨宝元构造嘉二1-嘉-气藏的储层特征、控制储层发育的主要因素，预测储层发育的有利分布区，提出夸后对该层的勘探建议。     

赤水地区二叠系及三叠系碳酸盐岩油气储集岩层研究

通过岩芯及露头研究，结合部分测井资料，系统研究了赤水地区二、三叠系储集岩岩石类型及其储集性能，主要储集空间类型及孔隙演化特征，探讨了各类储层的主要控制因素。研究发现三叠系非均质性较强，但纵横向上仍有一些可对比的储集层段。如以T2rl^1为代表的孔隙型储层。以及以T1c^21,t1c^1为代表的裂缝一孔隙型储层。二叠系储层的存在取决于构造裂疑发育带，断层发育带、地震异常带等三有利部位。岩溶储层的发育与否必须考虑到地层厚度的异常变化。三叠系储层主要受控于发育在膏盐层下的潮间带中粒屑滩微相的粒屑云岩的溶蚀作用和白云岩化作用。构造作用同时也促使了白云岩化的发育，t1c^21-T1c^11层的白云岩层厚度决定了其储集性能。     

石灰华扇(Tufa Fan)沉积物中的微型生物多样性

为了探索石灰华扇沉积物中微型生物多样性特征, 作者2006年7～9月对贵州中部马脚冲瀑布石灰华扇进行了野外生态学调查,釆集样品和标本50份。经室内初步分析和鉴定, 该瀑布石灰华扇中含有4大微型生物多样性类群共25个物种,它们是蓝细菌(Cyanobacteria)1个种,原生动物(Protozoan) 16个种,绿藻(Green algae) 1个种,硅藻(Diatoms)7个种。此外,石灰华扇中还发现了苔藓植物(Bryophytes)6个种。石灰华扇沉积物的形成,是微型生物多样性-石灰华扇沉积相互作用的地质生态学结果。     

贵州罗甸软玉矿的元素地球化学特征研究

罗甸玉是贵州首次发现的软玉矿,矿体赋存于晚二叠世辉绿岩与二叠系四大寨组灰岩接触带上。本文对辉绿岩、硅质岩、灰岩、大理岩及玉石共16件样品进行微量元素及稀土元素测试,数据分析结果表明:辉绿岩微量及稀土元素总量高,稀土元素配分曲线明显区别于其它样品;玉石、灰岩、大理岩及硅质岩地球化学性质相似,不同剖面玉石均表现为轻稀土富集及Ce与Eu明显负异常。结合玉石矿野外地质特征分析,认为玉石成矿并非岩浆直接作用的结果,而与侵入岩浆热驱动和岩浆带来气水热液作用关系更密切,提出罗甸玉两种成矿方式,即热驱动下岩层内部元素交代成矿和热液交代蚀变成矿。