甲基红褪色光度法测定地质样品中痕量锰

本文研究了MnO_4~-对甲基红的褪色作用,并借此分光光度法测定Mn。在1.0—2.0mol/L的H_2SO_4介质中,测定波长为515nm,Mn浓度在0—80μg/50ml范围同吸光度的减少值呈线性关系,灵敏度比MnO_4~-比色法高10倍。用于测定地质样品中的痕量Mn时,结果满意。     

Atmospheric Methyl Iodide at Cape Grim, Tasmania, from AGAGE Observations

Atmospheric mixing ratios of methyl iodide (CH₃I) and other methyl halides have been measured at Cape Grim, Tasmania (41°S, 145°E), since early 1998 as part of the Advanced Global Atmospheric Gases Experiment (AGAGE). This paper analyses about 1700 ambient air CH₃I measurements from the 14-month period (March 1998–April 1999). Mixing ratios peaked during the summer, despite faster photolytic loss, suggesting local oceanic emissions were about 2.2–3.6 times stronger in summer than in winter. Back trajectories show that CH₃I levels are strongly dependent on air mass origin, with highest mixing ratios in air from the Tasman Sea/Bass Strait region and lowest levels in air originating from the Southern Ocean at higher latitudes. CH₃I mixing ratios were not well correlated with other methyl halides in unpolluted marine air. The large variations with season and air mass origin suggest that high frequency, continuous data from key locations will make a significant contribution to the understanding of sources and sinks of this important short-lived atmospheric species.     

Product study of the reaction of OH radicals with isoprene in the atmosphere simulation chamber SAPHIR

Atmospheric oxidation of isoprene and its oxidation products methacrolein (MACR) and methyl vinyl ketone (MVK) have an important impact on the photochemical activity in the boundary layer, in particular in forested areas. The oxidation of isoprene by OH radicals was investigated in chamber experiments conducted under tropospheric conditions in the atmosphere simulation chamber SAPHIR at the Research Center Jülich. The aim was to determine the product yield of MVK and MACR in the OH-induced isoprene oxidation and the rate constant of their reaction with OH under real atmospheric conditions. The recently published updated degradation scheme for isoprene from Geiger et al. (2003) was used to determine rate constants and product yields. The fractional yields in the isoprene peroxy radical reaction with NO were found to be 0.41±0.03 for MVK and 0.27±0.03 for MACR. The rate coefficient for MACR with OH was found to be in very good agreement with the recommended value of IUPAC Atkinson (Atkinson et al., 2005). while the rate coefficient for MVK with OH was 27% lower.     

保山水汞异常与中强震关系研究

对云南保山滇14井1992—2004年水汞观测资料与其周围400km范围内发生的所有Ms≥95．0地震进行了研究。结果表明：在中强地震发生前,滇14井水汞存在短临异常,且异常特征清晰,异常幅度明显;所提取的短临预报指标对应地震效果较好,但对应范围受区域地质构造控制,主要对应云南西部地区及缅甸弧型构造带中的中强地震。     

Biodegradation and environmental behavior of biodiesel mixtures in the sea: An initial study

Biodiesel, a mixture of fatty acid methyl esters (FAMEs) derived from animal fats or vegetable oils, is rapidly moving towards the mainstream as an alternative source of energy. However, the behavior of biodiesel, or blends of biodiesel with fossil diesel, in the marine environment have yet to be fully understood. Hence, we performed a series of initial laboratory experiments and simple calculations to evaluate the microbial and environmental fate of FAMEs. Aerobic seawater microcosms spiked with biodiesel or mixtures of biodiesel and fossil diesel revealed that the FAMEs were degraded at roughly the same rate as n-alkanes, and more rapidly than other hydrocarbon components. The residues extracted from these different microcosms became indistinguishable within weeks. Preliminary results from physical-chemical calculations suggest that FAMEs in biodiesel mixtures will not affect the evaporation rates of spilled petroleum hydrocarbons but may stabilize oil droplets in the water column and thereby facilitate transport.     

马村站自512井水汞异常分析

2006年7月4日河北省文安县发生了ML5．5级地震,震前震中西南200km的石家庄马村站自512井水汞3月15日～5月15日出现了短期高值异常,6月3日出现了高值突跳异常。本文分析研究了文安地震前水汞的异常变化,以及1999年水汞观测以来的异常变化特征。分析认为,震前小马村水汞的异常变化幅度较大,异常特征明显,前兆意义显著。     

Total mercury in terrestrial systems (air-soil-plant-water) at the mining region of San Joaquín,Queretaro, Mexico

Deficient management of cinnabar mining left the San Joaquín region with high concentrations of mercury in its soils (2.4 – 4164 mg kg^-1). Numerous cinnabar mines have contributed to the dispersion of mercury into agricultural (0.5 –314 mg kg^-1) and forest (0.2 – 69 mg kg^-1) soils. Sediments are a natural means of transportation for mercury, causing its spreading, especially in areas near mine entrances (0.6 – 687 mg kg^-1). The nearness of maize crops to mines favors mercury accumulation in the different plant structures, such as roots, stems, leaves, and grain (0.04 – 8.2 mg kg^-1); these being related to mercury volatilization and accumulation in soils. Mercury vapor present in the settlements could indicate a constant volatilization from lands and soils (22 – 153 ng m^-3). The mercury levels found in the soils, in maize grain, and in the air resulted greater than the standards reported by the Official Mexican Norm (NOM) and the World Health Organization (WHO). Mercury in rainwater is due mainly to the presence of suspended atmospheric particles, later deposited on the surface (1.5 – 339 μg |^-1). Mercury dissolution was found in the drinking water (10 – 170 ng |^-1), with concentrations below those established by the NOM and the WHO. The contamination existing in the San Joaquín region does not reach the levels of the world’s greatest mercury producers: Almaden (Spain) and Idrija (Slovenia). It is, however, like that found in other important second degree world producers such as Guizhou (China). The population of San Joaquín, as well as its surrounding environment, are constantly exposed to mercury contamination, thus making a long term monitoring necessary to determine its effects, especially to people.     

水汞观测资料对比分析

通过聊古一井井水中汞量的测定及对比观测试验,找到了影响数据内在质量的干扰因素,提出了浓硫酸、蒸馏水是干扰因素的主要来源,进行空白样的测定是排除干扰,提高观测资料内在质量的重要方法.     

壤中气汞测量在活断层研究中的应用

利用JM—3型数字金膜测汞仪对渭河盆地活动断层进行壤中气汞测量,取得了初步结果。认为,壤中气汞异常与活动断层存在着密切的关系,通过测汞寻找隐伏活动断层,判定断层活动性是可行的。     

福州市大气汞含量及变化特征分析

在福州市采集了10个点位共356件大气样品,测试结果表明,福州市大气汞含量35.82~586.11 ng/m3,各点平均值89.86~168.24 ng/m3,总平均111.9 ng/m3,大气汞含量空间变化特征表明高含量点与地热活动带在空间上相吻合。