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 No- vember 2003 and February 2004 in accordance with trace metal protocols. The average concentrations of total mer- cury (THg), dissolved mercury (DHg), reactive mercury, dissolved gaseous mercury, total methylmercury, and dis- solved 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 oc- curred 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.

2016年宁夏回族自治区PM2.5浓度时空分布特征

对2016年宁夏回族自治区大气中PM2.5浓度的时空分布特征及其与其它空气质量指标和气象参数之间的相关性进行探讨。结果表明,宁夏回族自治区2016年PM2.5日平均浓度为2.0～217.5μg/m3;11月、12月、1月、2月PM2.5月浓度均值（45.97～87.22μg/m3）相对较高,6～9月的（19.01～38.03μg/m3）相对较低;春、夏、秋、冬PM2.5浓度分别为2.00～211.00μg/m3、6.67～106.67μg/m3、10.67～166.00μg/m3和10.50～217.50μg/m3;0：00～23：00,各城市PM2.5小时浓度基本上表现出先下降、后上升、再下降、再上升的变化规律,通常上午9：00～10：00浓度值较高,下午15：00～16：00浓度值较低。银川市、石嘴山市、吴忠市、中卫市和固原市2016年PM2.5日平均浓度≤75μg/m3的天数分别为304 d、307 d、313 d、323 d和340 d,年达标率分别为83%、84%、86%、88%和93%。宁夏北部的石嘴山市、银川市的PM2.5月浓度均值超过了南部的中卫市和固原市,表现出＂北高南低＂的趋势,其中固原市每月PM2.5浓度均值均低于其他城市,表现出显著差异。PM2.5浓度与CO、NO2、SO2、PM10浓度、风速、气压、日照和相对湿度均呈显著或极显著正相关关系,与地表温度、气温和降水量呈极显著或显著负相关关系。可见,宁夏回族自治区大气PM2.5浓度具有明显的时空变化特征,其浓度受气象因子的影响。

贵州东部某燃煤电厂汞排放对周边环境空气及土壤的影响

结合当地气象条件,测定贵州省东部某燃煤电厂下风向环境空气汞浓度分布情况,同时测定该燃煤电厂周边表层土壤中汞含量,并对其污染程度进行评价,探讨了土壤汞与理化性质间的相关性。结果表明,该燃煤电厂下风向环境空气汞浓度远高于北半球大气气态总汞背景值,空气汞浓度在2.7 km范围内随距离的增大而增大,在2.7~5.0 km范围内汞浓度随距离的增大而减小。电厂周边表层土壤汞含量是贵州省A层土壤Hg背景值的8.5倍,存在中度到重度程度的污染,土壤Hg与土壤pH呈正相关性,但与土壤有机质未表现出相关性。

食用大米人群甲基汞暴露健康风险及摄入量限值研究进展

汞(Hg)被联合国环境规划署列为全球性污染物,其不仅可通过大气进行长距离迁移,还具有持久性、高生物富集性和高生物毒性等特点。大米是世界一半以上人口的主食,食用大米人群甲基汞(MeHg)暴露已经成为一个全球性的环境健康问题。目前国际上制定的MeHg摄入量限值标准是基于3个地区(法罗群岛、新西兰和塞舌尔)食用鱼肉人群MeHg暴露的长期研究结果,而大米并不富含有鱼肉的有益物质,国际上制定的MeHg摄入量限值标准可能不适用于评估食用大米MeHg暴露的健康风险。从汞及其化合物的理化性质与毒性、MeHg暴露相关国际标准和限值、食用大米人群MeHg暴露的健康风险与评估方法三个方面系统阐述食用大米人群MeHg暴露的最新研究进展,可为我国人群汞日最大摄入量指标值的制定和汞暴露的健康风险评估与防控提供科学依据。

Annual Time-series Analyses of Total Gaseous Mercury Measurement and its Impact Factors on the Gongga Mountains in the Southeastern Fringe of the Qinghai-Tibetan Plateau

Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local,regional and global studies of atmospheric long-range transport processes,and they could also provide valuable information about the impact of emission controls on the global budget of atmospheric mercury,their observance and an insight into the global mercury cycle. China is believed to be an increasing atmospheric mercury emission source. However,only a few measurements of mercury,to our knowledge,have been done in ambient air over China. The highly-time resolved atmospheric mercury concen-trations have been measured at Moxi Base Station (102°72′E 29°92′N,1640 m asl) of the Gongga Alpine Ecosystem Observation and Experiment Station of Chinese Academy of Sciences (CAS) from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A). Measurements were carried out with a time resolution of every 15 minutes. The overall average total gaseous mercury (TGM) covering the measurement periods was 4±1.38 ng·m-3 (N=57310),which is higher than the global background level of approximately 1.5～2.0 ng·m-3. The measurements in all seasons showed a similar diurnal change pattern with a high concentration during daytime relative to nighttime and maximum concentration near solar noon and minimum concentration immediately before sunrise. The presence of diurnal TGM peaks during spring and summer was found earlier than that during autumn and winter. When divided seasonally,it was found that the concentrations of TGM were highest in winter with 6.13 ± 1.78 ng·m-3 and lowest in summer with 3.17 ± 0.67 ng·m-3. There were no significant differences in TGM among wind sectors during each season. Whereas Hg generally exhibited significant correlations with the parameters,such as temperature,saturated vapor pressure,precipitation,ultraviolet radiation (UV) and atmospheric pressure at the whole measurement stage,and the correlations varied seasonally. Our results suggest that the local or regional abundant geothermal activities,such as thermal spring,anthropogenic source processes and changes in meteorological conditions,regulate and affect Hg behavior in the study area.

Farmland mercury contamination in the vicinity of an organic chemical factory in Guizhou,China

This study assesses the level of contamination of Hg in farmland soils along the irrigating channel down-stream from Guizhou Organic Chemical Factory (GOCF),where metallic mercury is used as a catalyst to produce acetic acid. The total input of mercury into the environment,as announced by GOCF,is 140 t in the past 30 years (1971-2000). Sampling sites were chosen based on the distance from the source of pollution—the chemical factory. A total of 39 samples were collected from the study area and analyzed for total mercury concentrations and methyl mercury concentrations. The characteristics of vertical and horizontal distributions of total mercury and methyl mer-cury in the study area (farmland) are described in this paper. Much attention was paid to the transformation of inor-ganic Hg into organic mercury species in soils as well. The results showed that the farmland has been heavily con-taminated by Hg. Land cultivation activity,land utilization style and distance from the pollution source could be the dominant factors controlling the distribution of THg and MeHg. It is observed that active transformation of inorganic Hg into organic mercury species (MeHg) usually takes place in paddy soils.

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.

我国汞污染研究与履约进展

汞是毒性较强的重金属污染物之一,也是一种全球性的污染物。旨在控制和削减全球人为汞排放和使用的国际公约——《关于汞的水俣公约》(以下简称《水俣公约》)已于2017年8月正式生效,这标志着汞污染已成为当前重要的全球环境问题。目前,我国是汞生产、使用和排放量最大的国家,面临着汞污染控制和履行汞公约的巨大压力。基于此背景,文章系统阐述了我国汞的生产、使用和排放,汞的迁移转化与健康效应,《水俣公约》和我国汞污染控制及履约进展,并展望了需要重点开展研究的5个方面,以期为我国环境汞污染控制和履行《水俣公约》作出贡献。

植被生态系统汞的生物地球化学循环研究进展与挑战

汞是联合国环境规划署重点管控的全球性污染物.植被是联结大气圈与土壤圈的关键纽带,在全球汞生物地球化学循环中扮演着举足轻重的角色.植被生态系统是全球大气重要的汞汇,但由于大气-植被-土壤的汞界面交换过程及植物组织中汞的分布、来源与迁移转化规律及驱动机制认识不清,致使当前的全球汞生物地球化学循环模型缺失植被过程模块,无法厘定全球植被的大气汞汇通量.近年来迅速发展的汞同位素地球化学、同步辐射和微气象汞通量观测等新方法,为多层次解析不同类型植被与土壤及大气界面汞交换过程,阐明植物组织中汞的分布、来源与迁移规律提升了可能,能为进一步解决当前森林生态系统汞的生物地球化学循环的研究难点提供独辟蹊径的视角.

保留中柱经椎弓根开合式截骨术治疗老年僵硬性脊柱后凸畸形

目的探讨保留中柱经椎弓根开合式截骨术治疗老年僵硬性脊柱后凸畸形的疗效和安全性。方法回顾性分析2016年1月至2018年4月收治的12例老年僵硬性脊柱后凸畸形患者的病历资料,均采用保留中柱经椎弓根开合式截骨术治疗。记录所有患者的手术时间、术中出血量、术后引流量、手术并发症、腰痛和下肢痛疼痛视觉模拟评分(visual analogue scale,VAS)、Oswestry功能障碍指数(Oswestry disability index,ODI)和健康调查量表(the MOS item short from health survey,SF-36)。比较术前、术后及末次随访时矢冠状面矫正情况,矢状面参数包括腰椎前凸角(lumbar lordosis,LL)、骶骨倾斜角(sacral slope,SS)、骨盆倾斜角(pelvic tilt,PT)、矢状面平衡(sagittal vertical axis,SVA),冠状面参数包括腰椎侧凸Cobb角、C7椎体中心至骶骨中垂线距离(C7 vertebral body center to humeral vertical line distance,C7PL-CSVL)。结果12例患者均顺利完成手术,手术时间为(238.20±65.95)min(范围,159~361 min),术中出血量为(440.50±133.60)ml(范围,120~600 ml)。术前ODI为65.92%±6.96%,末次随访时为21.00%±3.19%,差异有统计学意义(t=20.32,P<0.0001)。术前SF-36评分为(76.42±4.31)分,末次随访时为(103.10±4.57)分,差异有统计学意义(t=4.246,P=0.003)。术前腰痛VAS评分为(6.00±0.95)分,术后3个月为(2.33±0.89)分,末次随访为(1.42±0.51)分;术前下肢痛VAS评分为(6.91±1.24)分,术后3个月为(2.50±1.00)分,末次随访为(1.50±0.52)分;术后3个月、末次随访时腰痛及下肢痛VAS评分与术前比较,差异均有统计学意义(P<0.05)。术后及末次随访时矢状面参数LL(F=17.47,P<0.001)、SS(F=5.015,P=0.0125)、PT(F=14.66,P<0.001)及SVA(F=81.11,P<0.001)均较术前明显改善。术后及末次随访时冠状面参数腰椎侧凸Cobb角(F=87.19,P<0.001)和C7PL-CSVL(F=100.9,P<0.001)亦均较术前明显改善。结论保留中柱经椎弓根开合式截骨术治疗老年僵硬性脊柱后凸畸形具有操作简单、手术时间短、术中出血少等优点,能够有效地改善患者腰腿痛症状和生活质量,矫正后凸畸形,维持患者脊柱-骨盆平衡状态。

Mercury isotope variations in surface soils in different contaminated areas in Guizhou Province,China

Guizhou Province is known as a heavily Hg-polluted area in China due to its special geochemical background and complicated Hg emission sources.In this study,we investigated the Hg isotope compositions of surface soil samples in the Hg mining area,zinc smelting area,coal combustion area,which are known to be the typical pollution regions of Hg in this province.We also compared the Hg isotopic fingerprints of primary Hg sources,such as hydrothermal Hg-bearing ores,coals and atmospheric Hg samples.According to our study,Hg stored in surface soils in different pollution regions in Guizhou Province displays a wide range of both mass dependent fractionation(MDF,δ202Hg) and mass independent fractionation(MIF,△199Hg).δ 202 Hg varies by 2.0‰ and △199Hg varies by 0.25‰ in the investigated surface soils.This study demonstrated that using a "MDF-MIF" two dimensional Hg isotope system could be particularly useful in discriminating Hg sources in soils.

Mercury speciation and spatial distribution in surface waters of the Yarlung Zangbo River,Tibet

The Yarlung Zangbo River is the highest river in the world.It flows from west to east through the southern part of Tibet.The mercury(Hg)speciation and distribution in surface waters and soils near the bank of the Yarlung Zangbo River and its two tributaries,the Lhasa and Niyang Rivers,were investigated in June 2007.Simultaneously,major water quality parameters were also measured at the same stations.Total Hg(THg)and total methylmercury(TMeHg)concentrations in surface waters of the Yarlung Zangbo River ranged from 1.46 to 4.99 ng/L and from 0.06 to 0.29 ng/L,respectively,representing the background levels in river systems of the Tibetan Plateau.Particulate Hg(PHg)accounted for 69%of the THg,and the two Hg species had a significant relationship(r=0.990,P<0.01).Approximately 61%of the spatial distribution of THg was controlled by the concentrations of total suspended particles(TSP).Reactive Hg(RHg)concentrations ranged from 0.10 to 0.36 ng/L,and this fraction may play a weak role in terms of the transport and fate of Hg in surface waters.Dissolved methylmercury(DMeHg)constituted 71%of the TMeHg and was significantly correlated with TMeHg(r=0.746,P<0.01).The spatial distribution of TMeHg is not strongly affected by environmental factors such as THg,RHg,temperature,pH,dissolved organic carbon(DOC),and TSP.In addition,the inflow of both the Lhasa and Niyang Rivers probably influences the concentrations of THg in surface waters of the mainstream, but such an effect is not obvious for TMeHg.

High-precision measurement of mercury isotope ratios of atmospheric deposition over the past 150 years recorded in a peat core taken from Hongyuan, Sichuan Province, China

High-precision 210Pb dating technology was applied to a peat core with a time span of about 150 years that was taken from Hongyuan, Sichuan Province, China. The concentrations of total mercury (Hg) and stable isotope compositions of mercury in the peat core were measured using a LUMEX 915 instrument and multi-collector inductively coupled plasma mass spectrometer, respectively. Total mercury (Hg) concentrations in the peat core had a clearly increasing trend from the bottom to top of the core while δ 202Hg values (relative to NIST 3133) of peat had a decreasing trend. The total mercury (Hg) concentration varied from 16.7 to 101.3 ng/g and the δ 202Hg values ranged from –0.44‰± 0.14‰ to –1.45‰± 0.22‰. We clearly show that the study area experienced mercury pollution after the industrial revolution, and the mercury emitted from natural sources and anthropogenic sources had different Hg isotope signatures.