Pre-column derivatization of amines with 1,2-benzo-3,4-dihydrocarbazole-9-isopropyl chloroformate followed by LC-fluorescence and LC-APCI-MS

A pre-column derivatization method for the sensitive determination of amines using the labeling reagent 1,2-benzo-3,4-dihydrocarbazole-9-isopropyl chloroformate (BCIC-Cl) followed by high-performance liquid chromatography with fluorescence detection has been developed. Identification of derivatives is carried out by high performance liquid chromatography/atmospheric pressure chemical ionization (LC-APCl-MS-MS). The chromophore of 2-(9-carbazole)-ethyl chloroformate (CEOC) reagent is replaced by 1,2-benzo-3,4-dihydrocarbazole-9-isopropyl functional group, which results in a sensitive fluorescence derivatizing reagent BCIC-Cl. BCIC-Cl can easily and quickly label amines. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography and show an intense protonated molecular ion corresponding m/z [MH](+) under APCl in positive-ion mode. The collision-induced dissociation of protonated molecular ion formed a product at m/z 260 corresponding to the cleavage of CH2-OCO bond. Studies on derivatization demonstrate excellent derivative yields over the pH 9.0-10.0. Maximal yields close to 100% are observed with a 3 to 4-fold molar reagent excess. In addition, the detection responses for BCIC derivatives are compared with those obtained using CEOC and FMOC as derivatization reagents. The ratios of l(BCIC)/l(CEOC) and l(BCIC)/l(FMOC) are, respectively, 1.23-3.14 and 1.25-3.08 for fluorescent (FL) responses (here, l is relative fluorescence intensity). Separation of the derivatized amines had been optimized on reversed-phase Eclipse XDB-C-8 column. Detection limits are calculated from 1.0 pmol injection, at a signal-to-noise ratio of 3, are 10.6-37.8 fmol. The mean interday accuracy ranges from 94 to 105% for fluorescence detection with the largest mean %CV < 7.5. The mean interday precision for all standards is < 6.0% of the expected concentration. Excellent linear responses are observed with coefficients of > 0.9997.

Development of a sensitive fluorescent derivatization reagent 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC) and its application for determination of amino acids from seeds and bryophyte plants using high-performance liquid chromatography with fluorescence detection and identification with electrospray ionization mass spectrometry

A pre-column derivatization method for the sensitive determination of amino acids and peptides using the tagging reagent 1,2-benzo-3,4dihydrocarbazole-9-ethyl chloroformate (BCEOC) followed by high-performance liquid chromatography with fluorescence detection has been developed. Identification of derivatives was carried out by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS/MS). The chromophore of 2-(9-carbazole)-ethyl chloroformate (CEOC) reagent was replaced by 1,2-benzo-3,4-dihydrocarbazole functional group, which resulted in a sensitive fluorescence derivatizing reagent BCEOC. BCEOC can easily and quickly label peptides and amino acids. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z (M + H)(+) under electrospray ionization (ESI) positive-ion mode with an exception being Tyr detected at negative mode. The collision-induced dissociation of protonated molecular ion formed a product at m/z 246.2 corresponding to the cleavage of C-O bond of BCEOC molecule. Studies on derivatization demonstrate excellent derivative yields over the pH 9.0-10.0. Maximal yields close to 100% are observed with a 3-4-fold molar reagent excess. Derivatives exhibit strong fluorescence and extracted detzvatization solution with n-hexane/ethyl acetate (10:1, v/v) allows for the direct injection with no significant interference from the major fluorescent reagent degradation by-products, such as 1,2-benzo-3,4-dihydrocarbazole-9-ethanol (BDC-OH) (a major by-product), mono- 1,2-benzo-3,4-dihydrocarbazole-9-ethyl carbonate (BCEOC-OH) and bis-(1,2-benzo-3,4-dihydrocarbazole-9-ethyl) carbonate (BCEOC)(2). In addition, the detection responses for BCEOC derivatives are compared to those obtained with previously synthesized 2-(9-carbazole)-ethyl chloroformate (CEOC) in our laboratory. The ratios AC(BCEOC)/AC(CEOC) = 2.05-6.51 for fluorescence responses are observed (here, AC is relative fluorescence response). Separation of the derivatized peptides and amino acids had been optimized on Hypersil BDS C-18 column. Detection limits were calculated from 1.0 pmol injection at a signal-to-noise ratio of 3, and were 6.3 (Lys)-177.6 (His) fmol. The mean interday accuracy ranged from 92 to 106% for fluorescence detection with mean %CV < 7.5. The mean interday precision for all standards was < 10% of the expected concentration. Excellent linear responses were observed with coefficients of > 0.9999. Good compositional data could be obtained from the analysis of derivatized protein hydrolysates containing as little as 50.5 ng of sample. Therefore, the facile BCEOC derivatization coupled with mass spectrometry allowed the development of a highly sensitive and specific method for the quantitative analysis of trace levels of amino acids and peptides from biological and natural environmental samples. (c) 2005 Elsevier B.V. All rights reserved.

中国北方表沙无机碳储量及次生碳酸盐固碳潜力研究

This paper selected the Taklamakan Desert and the Badain Jaran Desert as the research areas, tested the carbonate content of surface-sand samples of dunes using Eijkelkamp carbonate goniophotometer, and analyzed the spatial-distribution characteristics of carbonate and estimated the carbonate-stock and secondary carbonate-stock in 1m depth of surface sand in the Taklamakan Desert and the Badain Jaran Desert. In addition, the paper test XRD, SEM, TDA, stable carbon isotope and radioactive strontium isotope of lacustrine deposits in the Taklamakan Desert and carbonates, such as kunkar, root canal, lacustrine deposits, sinter and calcrete, in the Badain Jaran Desert. Resting on the achievements by our predecessors, it analyzed the mineral-composition differences of the carbonates, calculated the contents of secondary carbonate and, furthermore, evaluated their potential of sequestration of CO2 in the atmosphere. The overall goal of this study was to increase our understanding of soil carbonate in the context of carbon sequestration in the arid region in China. That is, to advance our understanding about whether or not secondary carbonate in desert is a sink for atmospheric CO2. The following viewpoints were obtained: 1 Carbonate contents of surface-sand samples decend from the south to the north of the Taklamakan Desert. The minimum lies in the south and the maxmum in the mid. Carbonate content of surface-sand of megadunes in the Badain Jaran Desert has low value generally in the dune-crest and the base of slope, and large value in the mid. The average of Carbonate contents of all sorts of collected samples in the same area of the Taklamakan Desert has small diffetences. The average is about 9%. 2 Using carbonate contents as key parameters, calculate the carbon-stock of carbonates in 1m depth of surface sand in the Taklamakan Desert and the Badain Jaran Deser.They are 1.13Pg and 0.19 Pg respectively. There are 0.53Pg and 0.088Pg carbon-stock of secondary-carbonates in 1m depth of surface sand in the Taklamakan Desert and the Badain Jaran Desert. 3 Through testing data from XRD （X-ray diffraction）and TAD ( Thermal Analysis Data), the most significant conclusion derived from is that the main mineral ingredient is calcite in different carbonate substances in arid regions, From the SEM(Scanning electron microscopy ) images, can obtains the information about the micro environment of different carbonate forms in which they can grow. 4 Selected gas by termal cracking and traditional phosphoric acid method, their δ13C show that δ13C is a good parameter to indicate the micro environment in which different secondary carbonate forms. From the δ13C of the same type samples, if the redeposit degree is hard, theδ13C is light, the redeposit degree is weak, the δ13C is heave. and the δ13C of the different type samples, δ13C is mainly controlled by the micro environment in which secondary formed. if the procedure is characterized by redeposit and dissolve of marine facies carbonate, δ13C is heavy, it is characterized by CO2 which produced by plant respiration,δ13C is light. 5 From the δ13C of lacustrine deposit in the different grain size, there exsit certain differences in their micro environment and secondary degree among different grain size in the same grade. 6 The secondary carbonate content of lacustrine deposits in Taklimakan Desert is 47.26%. And those of root canal, sinter, calcrete, kunkar, lacustrine deposit and surface sand in Badain Jaran Desert are 91.74%, 78.46%, 76.26%, 87.87%, 85.37%and 46.49%, respectively. Of different grain size samples, the secondary carbonate contents of coarse fraction (20-63μm), sub-coarse fraction (5-20μm) and fine fraction (<5μm) are 80.10%, 47.2%and 50.07%, respectively. 7 There is no obvious relevance betweenδ13C of secondary carbonate and the content of secondary carbonate,theδ13C of secondary carbonate mainly reflects the parameters of secondary process, the content of secondary carbonate reflects difference of secondary degree.. 8 Silicates potentially supply 3.4 pencent calcium source during forming process of lacustrine deposits in Taklimakan Desert. If calcium source is mainly supplied by goundwater, it can be calculated that about 5.18 %, 6.13%, 5.68%, 5.64 % and 6.82% silicates supply calcium source respectively for root canal, kunkar, lacustrine deposit, calcrete and sinter, during the forming process of different kinds of carbonates in Badain Jaran Desert.

柴达木盆地北缘地区油气成藏过程模拟与含油气系统评价

As an important part of petroleum exploration areas in the west of China, the north part of Qaidam basin is very promising in making great progress for petroleum discovery. But there are still many obstacles to overcome in understanding the process of petroleum formation and evaluation of oil & gas potential because of the complexity of geological evolution in the study area. Based upon the petroleum system theory, the process of petroleum formation is analyzed and the potential of oil & gas is evaluated in different petroleum systems by means of the modeling approach. The geological background for the formation of petroleum systems and the consisting elements of petroleum systems are described in detail. The thickness of strata eroded is estimated by means of vitrinite reflectance modeling, compaction parameter calculating and thickness extrapolating. The buried histories are reconstructed using the transient compaction model, which combines of forward and reverse modeling. The geo-history evolution consists of four stages - sedimentation in different rates with different areas and slow subsidence during Jurassic, uplifting and erosion during Cretaceous, fast subsidence during the early and middle periods of Tertiary, subsidence and uplifting in alternation during the late period of Tertiary and Quaternary. The thermal gradients in the study area are from 2.0 ℃/100m to 2.6 ℃/100m, and the average of heat flow is 50.6 mW/m~2. From the vitrinite reflectance and apatite fission track data, a new approach based up Adaptive Genetic Algorithms for thermal history reconstruction is presented and used to estimate the plaeo-heat flow. The results of modeling show that the heat flow decreased and the basin got cooler from Jurassic to now. Oil generation from kerogens, gas generation from kerogens and gas cracked from oil are modeled by kinetic models. The kinetic parameters are calculated from the data obtained from laboratory experiments. The evolution of source rock maturation is modeled by means of Easy %Ro method. With the reconstruction of geo-histories and thermal histories and hydrocarbon generation, the oil and gas generation intensities for lower and middle Jurassic source rocks in different time are calculated. The results suggest that the source rocks got into maturation during the time of Xiaganchaigou sedimentation. The oil & gas generation centers for lower Jurassic source rocks locate in Yikeyawuru sag, Kunteyi sag and Eboliang area. The centers of generation for middle Jurassic source rocks locate in Saishenteng faulted sag and Yuka faulted sag. With the evidence of bio-markers and isotopes of carbonates, the oil or gas in Lenghusihao, Lenghuwuhao, Nanbaxian and Mahai oilfields is from lower Jurassic source rocks, and the oil or gas in Yuka is from middle Jurassic source rocks. Based up the results of the modeling, the distribution of source rocks and occurrence of oil and gas, there should be two petroleum systems in the study area. The key moments for these two petroleum, J_1-R(!) and J_2-J_3, are at the stages of Xiaganchaigou-Shangyoushashan sedimentation and Xiayoushashan-Shizigou sedimentation. With the kinetic midels for oil generated from kerogen, gas generated from kerogen and oil cracked to gas, the amount of oil and gas generated at different time in the two petroleum systems is calculated. The cumulative amount of oil generated from kerogen, gas generated from kerogen and gas cracked from oil is 409.78 * 10~8t, 360518.40 * 10~8m~3, and 186.50 * 10~8t in J_1-R(!). The amount of oil and gas generated for accumulation is 223.28 * 10~8t and 606692.99 * 10~8m~3 in J_1-R(!). The cumulative amount of oil generated from kerogen, gas generated from kerogen and gas cracked from oil is 29.05 * 10~8t, 23025.29 * 10~8m~3 and 14.42 * 10~8t in J_2-J_3 (!). The amount of oil and gas generated for accumulation is 14.63 * 10~8t and 42055.44 * 10~8m~3 in J_2-J_3 (!). The total oil and gas potential is 9.52 * 10~8t and 1946.25 * 10~8m~3.

末次盛冰期以来中国陆地生态系统碳储量变化研究

Carbon is an essential element for life, food and energy. It is also a key element in the greenhouse gases and therefore plays a vital role in climatic changes. The rapid increase in atmospheric concentration of CO_2 over the past 150 years, reaching current concentrations of about 370 ppmv, corresponds with combustion of fossii fuels since the beginning of the industrial age. Conversion of forested land to agricultural use has also redistributed carbon from plants and soils to the atmosphere. These human activities have significantly altered the global carbon cycle. Understanding the consequences of these activities in the coming decades is critical for formulating economic, energy, technology, trade, and security policies that will affect civilization for generations. Under the auspices of the International Geosphere-Biosphere Programme (IGBP), several large international scientific efforts are focused on elucidating the various aspects of the global carbon cycle of the past decade. It is only possible to balance the global carbon cycle for the 1990s if there is net carbon uptake by terrestrial ecosystems of around 2 Pg C/a. There are now some independent, direct evidences for the existence of such a sink. Policymarkers involved in the UN Framework Convention on Climate Change (UN-FCCC) are striving to reach consensuses on a 'safe path' for future emissions, the credible predictions on where and how long the terrestrial sink will either persist at its current level, or grow/decline in the future, are important to advice the policy process. The changes of terrestrial carbon storage depend not only on human activities, but also on biogeochemical and climatological processes and their interaction with the carbon cycles. In this thesis, the climate-induced changes and human-induced changes of carbon storage in China since the past 20,000 years are examined. Based on the data of the soil profiles investigated during China's Second National Soil Survey (1979-1989), the forest biomass measured during China's Fourth National Forest Resource Inventory (1989-1993), the grass biomass investigated during the First National Grassland Resource Survey (1980-1991), and the data collected from a collection of published literatures, the current terrestrial carbon storage in China is estimated to -144.1 Pg C, including -136.8 Pg C in soil and -7.3 Pg C in vegetation. The soil organic (SOC) and inorganic carbon (SIC) storage are -78.2 Pg C and -58.6 Pg C, respectively. In the vegetation reservoir, the forest carbon storage is -5.3 Pg C, and the other of-1.4 Pg C is in the grassland. Under the natural conditions, the SOC, SIC, forest and grassland carbon storage are -85.3 Pg C, -62.6 Pg C, -24.5 Pg C and -5.3 Pg C, respectively. Thus, -29.6 Pg C organic carbon has been lost due to land use with a decrease of -20.6%. At the same time, the SIC storage also has been decreased by -4.0 Pg C (-6.4%). These suggest that human activity has caused significant carbon loss in terrestrial carbon storage of China, especially in the forest ecosystem (-76% loss). Using the Paleocarbon Model (PCM) developed by Wu et al. in this paper, total terrestrial organic carbon storage in China in the Last Glacial Maximum (LGM) was -114.8 Pg C, including -23.1 Pg C in vegetation and -86.7 Pg C in soil. At the Middle Holocene (MH), the vegetation, soil and total carbon were -37.3 Pg C, -93.9 Pg C and -136.0 Pg C, respectively. This implies a gain of-21.2 Pg C in the terrestrial carbon storage from LGM to HM mainly due to the temperature increase. However, a loss of-14.4 Pg C of terrestrial organic carbon occurred in China under the current condition (before 1850) compared with the MH time, mainly due to the precipitation decrease associated with the weakening of the Asian summer monsoon. These results also suggest that the terrestrial ecosystem in China has a substantial potential in the restoration of carbon storage. This might be expected to provide an efficient way to mitigate the greenhouse warming through land management practices. Assuming that half of the carbon loss in the degraded terrestrial ecosystem in current forest and grass areas are restored during the next 50 years or so, the terrestrial ecosystem in China may sequestrate -12.0 Pg of organic carbon from the atmosphere, which represents a considerable offset to the industry's CO2 emission. If the ' Anthropocene' Era will be another climate optimum like MH due to the greenhouse effect, the sequestration would be increased again by -4.3 - 9.0 Pg C in China.

硝化和反硝化对湖泊有机质沉积成岩前降解作用的研究

贵州红枫湖10月叶绿素a(chla)和NO3^-含量均比7月明显降低。利用氮同位素等数据对此进行了研究，结果表明，含量的降低是由不同的生物地球化学作用引起的。chla含量的降低主要是水体中有机质降解(硝化)所致，而NO3^- 含量的降低则是缺氧季节湖泊沉积物表层反硝化作用的结果。缺氧季节表层水体仍然能发生较强烈的硝化作用。硝化作用和反硝化作用分别发生在热分层湖泊的上层和沉积物表层。反硝化作用不仅消耗大量的NO3^-，而且还造成了一定量的有机质降解(有机碳作为电子受体)。据估算，在红枫湖后五测点和大坝测点，总有机碳在沉积成岩前分别降解了78％和68％。其中由硝化作用引起的总有机质降解量分别为35．8%和25．9％，而反硝化作用则分别为13．4％和9．2％.

黔北早寒武世缺氧事件：生物标志化合物及有机碳同位素特征

本文首次报道了黔北早寒武世黑色岩系的生物标志化合物，并结合有机碳同位素组成特征，探讨该时期所发生的重大地质事件。所有样品均检出了丰富的正构烷烃、类异戊二烯烃、萜类化合物以及甾类化舍物。在GC谱图上，正构烷烃显示明显的单峰型分布特征，碳数分布范围为nC14-nC31主峰碳为nC18、nC19或nC20，nC17／nC31为1．15～50．17，显示轻烃组分占绝对优势，OEP值为0．84～1．11，CPI值为0．92～1．16，接近平衡值1．0，无明显的奇偶碳数优势分布。Pr／Ph值为0．24～0．79，具有明显的植烷优势。萜烷化合物以C30藿烷占优势，其相对丰度三环萜烷〉五环三萜烷〉四环萜烷，并且检出少量的γ-蜡烷。规则甾烷C27-C28-C29呈“V”字型分布，∑（C27＋C28）〉∑C29，其比值为1．25～1．99，∑C27／∑C29为0．78～1．22，重排甾烷C27／规则甾烷C27值为0．21～0．47。4-甲基甾烷普遍存在，但丰度相对较低。在地层剖面上，有机碳含量（TOC（％））从0．05～7．91％，平均为2．52％；有机碳同位素组成（δ^13Corg）从-29．49‰～-34．41‰（PDB），发生负偏移，偏移量达到4．3‰，代表该期海平面处于上升阶段，底层水处于严重缺氧状态，底栖生物缺乏。本文根据生物标志化合物特征参数，结合有机碳同位素组成变化，详细分析了黔北早寒武世这套黑色岩系的有机质来源、成熟度、沉积环境以及古海洋意义，将为我国南方早寒武纪古地理重建、地质事件记录提供可靠依据。

四川冕宁稀土矿床碳酸岩PGE地球化学初步研究

报道了四川冕宁稀土矿床碳酸岩7件样品的PGE和Au含量分析结果，其含量（WB／10^-9）范围分别为Ir0．5～0．78，Ru 1．61～6．75，Rh 0．08～0．14，Pt 2．62～12．15，Pd 1．11γ3．65和Au1．24～8．61。原始地幔标准化的PGE模式呈Ru、Pt、Pd相对富集和Ir、Rh相对亏损的“燕子型”。分析认为，碳酸岩具有一定携带PGE的能力；本区碳酸岩具“燕子型”PGE配分模式可能是其源区地幔PGE配分模式的反演；深源富CO2流体交代作用原始地幔可能是形成其“燕子型”PGE配分模式主要因素。

西秦岭南亚带层控金－硒矿床的赋矿地层年代与成矿时代

西秦岭南亚带层控金硒矿床的赋矿地层为太阳顶群 ,为一套主要由炭质硅岩和炭质板岩组成的硅岩建造。对于太阳顶群的时代 ,至今仍众说纷纭 ,莫衷一是 ,大多数人认为属晚寒武世—奥陶纪 ,也有认为属晚震旦—早寒武世。作者通过对古杯类化石的鉴定以及Rb Sr、Sm Nd同位素等时线年龄测定后认为 ,赋矿的太阳顶群时代应属早寒武世 ,而非晚寒武世—奥陶纪 ,更不可能为晚震旦世。对金硒矿床中 2个成矿阶段石英样品进行40 Ar/ 3 9Ar快中子活化测定后获得马鞍型谱线特征。其中坪年龄 (71 .4 5± 0 .5 5 )～ (80 .0 5± 0 .6 5 )Ma、最小视年龄 (70 .2 4± 1 .93)～ (78.5 9± 2 .85 )Ma和等时线年龄 (6 9.4 5± 0 .38)～ (81 .6 1± 0 .5 5 )Ma均十分接近 ,说明所测 2件石英样品的40 Ar/.

粤北石英脉型钨多金属矿床中钨锡铋银钼的赋存状态研究

本文对粤北红岭、石人嶂、梅子窝、锯板坑等四个石英脉型钨矿的矿石样品进行了详细的矿相学和电子探针分析,在红岭钨矿中观察到黑钨矿与白钨矿共生或交代现象,并发现铌锰矿、(含)钨铌锰矿晶体。在石人嶂、梅子窝、锯板坑钨矿中发现较多黝锡矿,分布在黄铜矿、闪锌矿边缘,或呈乳滴状分布在黄铜矿中,部分黝锡矿中包裹锡石。红岭、石人嶂、梅子窝钨矿床中有不同程度的银矿化,根据(含)银矿物的能谱成分分析,区分出富硫铋铅矿、块辉铋铅银矿(第1、2、3亚种)、硫银铋矿、淡红银矿、脆银矿、硫铜银矿,并有含银4.78%～13.25%的硫铅铋盐、含银2.9%～12.19%的硫铜银盐、含银71.01%～90.74%的硫砷银盐及含银9.3%的硫氯铅铜盐等多种未定名矿物。红岭钨矿中含银矿物多以不规则粒状分散在铁闪锌矿、硅酸盐矿物中,含银矿物与主硫化物同时形成;石人嶂钨矿床中含银矿物主要为含银硫铜盐、硫铜银盐,在黄铜矿边缘形成含银矿物-闪锌矿的交代反应边,局部有含银硫铅铋盐、硫铋银盐;梅子窝钨矿床中主要为独立银矿物和少量自然银,多分布在方铅矿中或充填在硫化物裂隙中,含银硫铅铋盐、硫铋盐、硫砷铅银矿物较少。石人嶂、梅子窝钨矿床中银矿物种类丰富且含量较高,具有综合利用前景,两矿床部分样品中发育细脉型或边缘交代型的(含)银矿物,表明晚期热液叠加银矿化作用较强。四个矿床中的铋矿物主要为辉铋矿和自然铋,部分矿床中多含银铅铋硫盐类,在红岭钨矿中发现与辉铋矿共生的楚碲铋矿,石人嶂钨矿中有细脉状未定名铋铜硫盐。四个矿床的闪锌矿成分不同,石人嶂、梅子窝钨矿的含较高Cd,红岭、锯板坑钨矿的基本不含Cd,红岭钨矿闪锌矿中Fe含量变化较大.

贵州红枫湖汞的生物地球化学循环

上世纪八十年代，科学家们发现在北美和北欧一些远离汞污染源的湖泊中，某些鱼汞含量远远超过了世界卫生组织建议的食用水产品汞含量标准，这一现象引起了人们对水环境系统中汞的生物地球化学循环的极大关注。因此本论文对贵州红枫湖和加拿大安大略省3个小湖中汞的形态与分布特征进行了详细的研究，并对红枫湖整个汞的生物地球化学循环做了较为完整深入的探讨。本论文主要包括以下4方面的研究内容：（1）沉积物甲基汞分析方法的建立；（2）红枫湖水体、沉积物、鱼体中各种汞形态的含量、分布特征以及水体富营养化对其影响的研究；（3）红枫湖汞形态转化、输入输出通量及其质量平衡的估算；（4）红枫湖的对比研究点—加拿大安大略省的Mary、St. George和Philips湖中不同形态汞分布特征的初步研究。通过本论文的研究，得出以下主要结论： 1. 建立了硝酸和硫酸铜溶液浸提，CH2Cl2萃取并结合水相乙基化和GC-CVAFS测定沉积物及土壤中甲基汞的方法。该方法平均回收率为 97.8%，相对标准偏差≤10.2%，方法检出限为0.6pg/g，具有所需试剂少、不用连续萃取、简捷易行、回收率高以及精密度好等特点。 2． 2004年红枫湖湖水总汞浓度在2.5-14 ng/L之间，平均值为6.9 ng/L；溶解态汞浓度范围在1.2-8.0 ng/L之间，平均为3.9 ng/L。不管是红枫湖水体汞浓度的空间分布，还是季节变化都严重受到人为污染源的干扰。湖水汞在颗粒态和溶解态之间的分配，主要受内源有机质以及氧化还原条件的影响。2004年春季后五由于水华现象大量繁殖的藻类，吸附了大量的汞，从而改变了汞在水库中的分配和迁移。这些藻类的生长对水体中溶解气态汞浓度分布也有显著的影响。湖水中活性汞分布特征主要受Hg2+的光致还原过程、Hg2+的甲基化过程以及人为源的输入等过程控制。 3. 红枫湖夏季下层滞水带中，甲基汞含量显著升高，特别是在后五缺氧层，最高值达0.92ng/L。夏季总甲基汞和溶解态甲基汞在水体剖面上的分布表明：在富营养化较严重的后五，水体中升高的甲基汞主要来自水体中汞的甲基化过程；而在富营养化特征不明显的大坝，水体中升高的甲基汞主要来自沉积物甲基汞的释放。红枫湖水体中各种汞形态的分布特征表明，富营养化对汞的迁移转化影响显著，尤其是汞的甲基化过程。水体富营养化为汞的甲基化提供了有利条件，给水生生态环境及人体健康带来了潜在的威胁。 4. 红枫湖沉积物总汞浓度为0.392 ± 0.070 μg/g，高于世界其它背景区汞浓度，也高于处于同一流域的乌江渡水库和东风水库，表明红枫湖受到了一定程度的汞污染。两个采样点总汞无明显的季节变化，但其剖面分布都有在上层富集的趋势。沉积物甲基汞浓度的季节变化和剖面最大峰值分布，主要受氧化还原带的季节性迁移所控制。沉积物甲基汞浓度在春季最高，其余季节则没有明显差异，甲基汞峰值出现在表层0～8cm以内，与红枫湖沉积物中硫酸盐还原菌活动区域一致。 5. 红枫湖总汞在孔隙水中的浓度及在固/液之间的分配系数主要和温度有关，与沉积物中总汞相关性不大，而孔隙水中甲基汞浓度则和沉积物甲基汞浓度存在着极显著的相关性（r=0.70, p<0.001）。沉积物和孔隙水甲基汞浓度除受到固/液分配系数影响外，主要还受到甲基汞产生过程控制。 6. 由于本次研究所采集的鱼类多为红枫湖人工饲养鱼，生长速度快，食物链短，故总汞含量（32ng/g）和甲基汞含量(12ng/g)都远远低于国家食用标准。汞含量在不同鱼种中的分布趋势为：肉食性鱼类>杂食性鱼类>草食性鱼类，这表明鱼体中汞含量主要和鱼的摄食习惯有关。 7． 红枫湖总汞质量平衡模型的估算结果表明，红枫湖水体中汞的总源为30066 g.a-1，总汇为31010g.a-1。水体中总汞最大的源来自于河流输入（82%），而最大的汇是水体颗粒态汞的沉降（78%）。甲基汞质量平衡模型的估算结果表明河流输出是水体甲基汞一个重要的汇，占总汇的45%, 比河流输入占总源的比例高30%，表明水库是下游水体甲基汞的源。 8. 红枫湖汞在水-沉积物界面的迁移通量表明，沉积物是水体中汞和甲基汞一个巨大的汇，而沉积物对上覆水体总汞和甲基汞的贡献却很有限。红枫湖汞在水-气界面的迁移通量表明，大气汞沉降特别是干沉降是红枫湖水体总汞一个重要的污染源，其对红枫湖汞的贡献远大于水体向大气释放的汞，大气沉降每年向红枫湖净贡献汞量为3364 g.a-1。 9. 在对比研究的湖泊中，水体中甲基汞的剖面分布表明，斜温层颗粒态甲基汞的沉降、沉积物甲基汞的释放以及水体汞的甲基化过程都是下层水体高甲基汞的重要来源。在这些湖泊中近代汞的沉积通量为22.1 μg m-2 a-1，远低于红枫湖中汞的沉积通量（714 μg m-2 a-1）。与红枫湖以及一些典型的沉积物甲基汞的垂直剖面分布相比，这些小湖中甲基汞的产生不仅发生在沉积物表层，在较深的沉积物中可能也有汞的甲基化过程，而且这个过程和有机质的含量密切相关。

吉林省长白山地区大气中不同形态汞的含量分布及沉降通量研究

汞是一种可以通过大气进行长距离跨国界进行传输的污染物，为了正确认识汞的全球大气循环演化规律，应该在全球不同区域内开展背景区大气不同形态汞含量的长期和高时间分辨率的观测研究。本论文工作利用高时间分辨率自动大气测汞仪（Tekran®2537A），于2005年8月～2006年7月对长白山地区大气气态总汞进行了连续一年的野外观测，同时按季节对该区大气中的颗粒态汞与活性气态汞进行了采集和分析。 研究结果表明，长白山地区大气气态总汞（TGM）的年平均含量为（3.22±1.78）ng•m-3。长白山地区大气气态总汞含量高于北半球大气汞含量的背景值(1.5~2.0 ng•m-3)，表明该地区已受到一定程度的大气汞污染。该区气态总汞表现出季节变化规律，含量高低按季节表现为：冬季（3.61ng•m-3）>春季（3.44ng•m-3）>秋季（3.15ng•m-3）>夏季（2.56ng•m-3）。在对长白山地区大气汞来源的解析中，该区频率最高的指示风向西南（SW）、西北（NW）和非主导风向东北（NE）方位上，城镇人为采暖、燃煤和对生物燃料的使用成为该地区的大气汞的主要人为来源，而土壤释汞和其他来源的大气汞经中长距离迁移也是造成该区大气汞含量偏高的原因。 对长白山地区不同时段的颗粒态汞（PM）与活性气态汞（RGM）含量的研究结果发现，采样期间颗粒态汞含量平均值为（77±136）pg•m-3，活性气态汞含量平均值为（65±84）pg•m-3。利用该结果计算了不同形态汞对长白山地区大气汞的组成。结果显示气态原子汞的贡献比例最大，约为94.0%；其次为颗粒态汞（PM<2.5），贡献比例为2.4%；活性气态汞的比例2.0%；贡献最小的是颗粒态汞（PM>2.5），所占比例1.6%。 论文工作还测定了长白山地区一年的大气降水中的总汞浓度，利用该雨水中的总汞含量估算该地区一年汞的湿沉降通量，同时用穿透雨（Throughfall）方法和模型法对大气中汞的干沉降进行估算。结果表明：长白山地区大气汞的干沉降通量大于湿沉降通量，干、湿沉降通量分别为16.5μg•m-2•a-1（模型计算为20.2μg•m-2•a-1）和8.4μg•m-2•a-1，且大气汞的总沉降通量为24.9μg•m-2•a-1。

中国西南地区大气降水中低分子有机酸研究（以贵阳市和尚重镇为例）

近几年随全球变暖和大气污染的加剧，有机气溶胶对气候和环境的影响引起了广泛的关注。其中低分子有机酸由于易溶于水，易挥发等特性可以改变大气颗粒物吸湿性、粒径分布以及形成云凝结核活性，进而改变全球的水循环和辐射平衡，而日益成为大气化学研究的重要内容。低分子有机酸极强的水溶性使雨水成为研究大气有机酸的理想载体。有机酸进入降水后是降雨的酸度重要贡献者，尤其是边远地区有机酸对降水酸度贡献高达65%。传统的大气降水研究主要侧重无机离子，认为硫酸和硝酸是降水酸度的主要贡献者，而忽略对降水中有机组分的研究。以贵阳和重庆等为代表的西南地区是我国酸雨污染的重灾区，该地区是典型喀斯特地形地貌区，生态环境具有极端的脆弱性和破坏后难以恢复性，在该地区研究酸雨形成和影响因素具有特殊的重要意义。本研究选取典型酸雨区(贵阳市)和人为污染较少黔东南州黎平县尚重镇为研究对象，2006-4～2007-4期间，收集大气降水样品221个，测定了大气降水中7种有机酸和主要阴、阳离子。对有机酸对酸雨的贡献及大气降水中无机离子和有机酸的浓度分布、变化规律、主要来源和沉降通量进行研究。主要得到了以下几点认识： 1、建立了离子色谱同时测定雨水中有机酸和无机酸分析条件。以戴安AS11-HC为分离柱、AG11-HC为保护柱，RFC-30淋洗液发生器在线产生KOH淋洗液，主要梯度条件为1mmol ( 0～6min) 、1mmol～30mmol (6～31min)。淋洗液流速1.5ml/min，柱温39℃。此条件下主要有机酸线性相关系数0.9992~0.9999，RSD%≤5%，精密度RSD%≤5%(丙酮酸RSD%=13.8%)，样品的加标回收率在80~120%之间，满足分析测试要求。 2、 贵阳市降水样品pH值的分布范围为2.49～6.92，年均值为3.28。雨水酸化率为73.8%，其中pH值小于4.0雨水占样品总数42%。尚重镇降水样品pH值的分布范围为5.01～6.50，年均值为5.83，降水的酸雨率为18.4%。贵阳市酸雨污染仍十分严重，重酸雨尤为突出(pH<4.0)，尚重镇酸雨污染较轻。 贵阳市降水样品电导率在10～1028μS/cm之间，平均值为248μS/cm，降水电导率高反映了贵阳市大气污染显著。尚重镇降水样品电导率在2.2～52.8μS/cm之间，平均值为18.1μS/cm，降水电导率低反映大气污染较轻。 3、贵阳市大气降水主要无机离子是SO42-、NO3-、H+、Ca2+、NH4+，雨量加权平均浓度分别为154.1μmol/L、33.9μmol/L、520.7μmol/L、226.4μmol/L和158.3μmol/L。采样期间，贵阳市H+年沉降通量为496.9mmol/m2/yr，夏季H+沉降占全年沉降总量的78%，贵阳市SO42-年沉降通量达到151.5mmol/m2/yr，有195.3mmol/m2/yr的Ca2+沉降。NH4+、Mg2+、Na+、K+、NO3-、Cl-的沉降通量分别为138.7mmol/m2/yr、50.9mmol/m2/yr、26.8mmol/m2/yr、11.4mmol/m2/yr、32.3mmol/m2/yr和12.6mmol/m2/yr。 尚重镇贵阳市大气降水主要无机离子是SO42-、NO3-、Ca2+、NH4+，其雨量加权平均浓度分别为43.1μmol/L、19.3μmol/L、33.0μmol/L和49.5μmol/L。采样期间，尚重镇[H+]年沉降通量为0.5mmol/m2/yr。SO42-、Ca2+和NH4+是发生沉降主要离子，分别为13.9mmol/m2/yr、10.6mmol/m2/yr和15.9mmol/m2/yr。Mg2+、Na+、K+、NO3-、Cl-的沉降通量分别为2.1mmol/m2/yr、5.9mmol/m2/yr、3.0mmol/m2/yr、6.2mmol/m2/yr和3.2mmol/m2/yr。 4、在贵阳市、尚重镇大气降水中共检测出7种低分子有机酸，分别是甲酸、乙酸、草酸、丙酮酸、丙酸、甲烷磺酸和乳酸。其中甲酸、乙酸和草酸是三种主要的有机酸。贵阳市甲酸、乙酸和草酸年平均浓度分别为14.24μmol/L、9.35μmol/L和2.79μmol/L，而在尚重镇它们浓度分别为4.95μmol/L、1.35μmol/L和2.31μmol/L。根据酸平衡常数计算法，贵阳市有机酸对自由酸贡献分别为：甲酸-7.9%，乙酸-4.7%，草酸-6.1%，三种主要有机酸贡献了18.7%的自由酸；尚重镇有机酸对自由酸贡献分别为：甲酸-25.1%，乙酸-7.5%，草酸-25.5%，有机酸对自由酸贡献率为58.1%。贵阳市有机酸占阴离子比值1.7～19.2%，平均值为6.6%。尚重镇有机酸对阴离子的贡献为0.5～92.2%，平均值为13.2%。有机酸对酸雨形成和大气降水化学起不可忽视的重要作用。 采样期间，贵阳市甲酸、乙酸和草酸的湿沉降通量分别为13.5mmol/m2/year 、8.9mmol/m2/year和2.6mmol/m2/year，甲酸和乙酸干沉降通量分别为26.7mmol/m2/year 和14.5mmol/m2/year，干沉降和湿沉降是贵阳市有机酸的主要沉降形式。尚重镇甲酸、乙酸和草酸的湿沉降通量分别为1.59mmol/m2/year 、0.43mmol/m2/year和0.04mmol/m2/year，甲酸和乙酸干沉降通量分别为0.1mmol/m2/year 和0.17mmol/m2/year，湿沉降是尚重镇有机酸的主要沉降形式。 5、尚重镇大气降水有机酸生长季节浓度高于非生长季节浓度，说明生长植物或土壤的释放可能是尚重镇大气有机酸的主要来源。贵阳市大气降水中有机酸非生长季节浓度高于生长季节浓度，主要原因是贵阳市降雨主要发生在夏季，降雨量的增加加大了对大气中微量气体的淋滤作用，降低了大气中有机酸浓度，同时夏季降雨pH值较低也不利于雨水对大气有机酸的溶解吸收。气象条件是影响有机酸浓度的重要因素。贵阳市大气有机酸主要在降雨初期进入降水并被清除的，降雨初期(1～2h)对大气有机酸清除占总清除的50～80%。随降雨的进行雨水中有机酸浓度逐渐降低，降雨后期略有升高，大降雨量对雨水中有机酸浓度起稀释的作用。尚重镇降雨量对有机酸浓度影响作用不明显，说明有机酸浓度不受雨量稀释作用控制，在降雨过程可能存在有机酸的液相来源。不同来源气团对贵阳市雨水中有机酸浓度影响不同，其中以北面方向气团降水中有机酸最高，与我国内陆大气污染较重有关。而源于海洋方向的东南气团雨水中有机酸浓度最低。 6、利用统计分析方法(相关性分析、主成分分析和聚类分析)和有机酸来源判别方法结合不同的来源释放有机酸通量得出：尚重镇大气中有机酸主要来源植物或者土壤直接或间接释放，而贵阳市有机酸来源相对复杂，其中植物的直接释放和机动车辆尾气排放不是大气有机酸的主要来源，生物质燃烧直接释放以及植物和人类活动向大气排放大量的不饱和有机物大气氧化可能是大气有机酸的重要来源。 7、从大气降水的电导率和pH值对比来看，贵阳市大气污染严重，雨水酸化率高，尚重镇大气污染较轻，雨水酸化率低。贵阳市大气降水中水溶性离子浓度是尚重镇的2～5倍左右，尚重镇地区酸沉降只有贵阳市0.1%，酸沉降对尚重镇不会造成太大影响。有机酸占贵阳市大气降水自由酸的19%，而尚重镇有超过1/2的自由酸是来源于低分子有机酸，是边远地区大气降水酸度的主要贡献者。来源分析表明尚重镇有机酸主要为生物源，贵阳市有机酸为人为源和生物源并重。 8、 传统的大气降水化学研究主要侧重于无机离子的研究，而忽略了对大气降水中有机组分的研究。本文第一次较全面、系统的研究了西南典型酸雨污染区大气降水化学组成以及降水酸度的来源，指出有机酸组分是西南地区大气降水化学的重要组成部分，对酸雨形成有不可忽视的影响。

贵阳市不同土地利用方式土壤有机碳地球化学研究

本研究根据贵阳市区域内不同土地利用方式，选择了自然土壤、农业土壤和城市土壤为主要研究对象。对表层土壤实行多样点的统计分析、以及典型剖面有机碳迁移过程分析，同时结合同位素地球化学示踪原理，探讨了贵阳市区域内土地利用方式变化对土壤有机碳的影响，以及不同土地利用方式间土壤有机碳的来源和降解过程的差异。主要结论如下： (1) 自然土壤转化为农业土壤后，表层(0～10cm) SOC有较为明显的降低趋势。其中，相对于自然土壤(黄壤) 表层SOC(平均值)而言，玉米地、水田、果园下降了40%左右，菜地下降了15%左右。然而，不同菜地土壤间耕种强度存在较大差异，其SOC变异程度高于其它几类农业土壤(CV＝57.07%)。与之相反，农业土壤表层DOC(18.86～48.20mg•L-1)接近或超过自然土壤(10.74～36.30 mg•L-1)，且ƒDOC占SOC的比例明显大于自然土壤。其中，玉米地DOC最高(平均值：48.20mg•L-1)，菜地次之(平均值：30.00mg•L-1)，果园第三(平均值：29.87mg•L-1)，水田最低(平均值：18.86mg•L-1)，但水田由于干湿交替的影响，DOC的变异程度最大(CV＝128.57%)。据此推断，在相同气候条件下，自然土壤转化为农业土壤后，由于表层DOC数量和比例的增加，提高了SOC的迁移性，进而加速了碳素在土壤中的迁移转化进程。 (2) 自然土壤转化为农业土壤后，剖面内部(>10cm)多数层次SOC相对于黄壤和黄色石灰土有明显的增加趋势。且通过对不同类型农业土壤人为干扰强度的调查表明：人为干扰强度越强，剖面中一定深度内SOC增加幅度越大。即：离城市较近的菜地2增长最为突出，果园其次，水田和玉米地相当。离城市较远的菜地1由于受人为干扰层次较浅，且出现了犁底层，剖面内SOC的含量水平与黄色石灰土相当。 (3) 原始土壤经搬运重组后形成城市公路绿化带土壤，表层SOC和DOC变幅较宽、离散程度较大，且没有随时间或植被类型等因素的变化而呈现明显的变化趋势。其中，SOC变异程度依次为新成公路绿化带2(CV＝58.0％)、老成公路绿化带(CV＝55.5％)、新成公路绿化带1(CV＝34.1％)。DOC变异程度依次为新成公路绿化带1(CV＝93.8％)、新成公路绿化带2(CV＝85.7％)、老成公路绿化带(CV＝78.0％)。 (4) 在自然土壤、农业土壤和城市绿化带土壤表层中，DOC与SOC、N、C/N、NO3-、NH4-，以及粘粒含量等的相关性均未达到显著水平。另据方差分析显示：果园、水田、菜地和玉米地表层土壤间DOC、SOC含量均无显著差异，说明农业土壤利用方式不是决定土壤表层SOC和DOC含量的绝对因素；新成公路绿化带1，2和老成公路绿化带表层土壤间DOC、SOC含量均无显著差异，说明植被类别和形成时间不是决定土壤表层SOC和DOC含量的绝对因素。 (5) 自然土壤中，枯枝落叶转化为表层(0～5cm)土壤有机质后，δ13CSOC值升高了1~4‰。通过不同碳源间δ13Corg相互关系的判断，在具备枯枝落叶覆盖的表层土壤中，DOC主要来源于枯枝落叶；而在土壤剖面内，随土壤剖面深度的增加，来自于土壤腐殖类物质的DOC占土壤DOC总量的比例呈增加趋势。在黄壤和黄色石灰土中(>5cm土层)，土壤剖面中大多数层次DOC比SOC更富13C。 (6) 大多数农业土壤有机碳δ13C值显示其有机肥源中存在C4-C源。且农业土壤中受碳源多样性的影响，菜地、果园、水田和玉米地表层土壤中δ13CSOC与δ13CDOC的相关性均未达到显著水平。其次，除玉米地土壤剖面外，其它供试农业土壤剖面大多数层次δ13CDOC值比δ13CSOC偏负，说明菜地、果园、水田土壤DOC主要为外源的加入。 (7) C3植被转化为C4植被(林-农生态系统转化)后，玉米地剖面中SOC有2.55％～20.80％源于C4-C，随剖面层次的加深有降低趋势，但表现为“之”字形反复；DOC中C4-C的比例在剖面0～40cm处较为相近(25.94％～34.54％)，40cm以下则急剧下降(3.18％～15.65％)。说明玉米地剖面 DOC主要来源于土壤腐殖类物质的转化。与林-农生态系统转变过程中的变化趋势相反，洼地农业土壤退耕弃荒一段时间(林-农-林生态系统转化)后，土壤剖面内C4-C占SOC的比例随土壤层次的加深逐渐增加，变化范围在5.77～26.76％。 (8) 在C3植被转向C4植被(林-农生态系统转化)后，玉米地δ13CSOC值与C4-C、C3-C相关系数(r)分别为0.372和-0.102，δ13CDOC值与C4-C、C3-C相关系数分别为0.131和-0.339，其相关性均未达到显著水平。而再从C4植被转回C3植被后，土壤δ13CSOC与C3-C之间呈显著相关性（r=0.88，n＝7），说明退耕弃荒后新加入的C3-C对土壤δ13CSOC值影响较大。其SOC的主要来源于洼地周边坡面土壤的侵蚀堆积物和新生草本植被残体。结合当前SOC降解过程的研究成果，本研究认为：洼地土壤退耕弃荒后一段时间里，土壤SOC可能处于累积大于损失状态。这有利于土壤性状向良性方向发展。 (9) 根据同位素值的相互关系和有机碳的来源调查，判断公路绿化带土壤中C4-C为原始土壤所带来。大气颗粒物和雨水中的DOC是表层土壤DOC的主要来源。公路绿化带土壤剖面中，随着时间的增加，土壤腐殖类物质与DOC的相互转化逐渐加强。 上述结论可为人类认识城市区域(特别是有强烈酸性沉降历史的喀斯特城市区域)土地利用方式改变对土壤碳循环的影响，以及不同土地利用方式间土壤有机碳迁移转化过程提供科学依据，也可为正确评估城市区域土壤与其他圈层间碳循环的源、汇关系提供基础资料。

贵州省遵义市大气降水中有机和无机地球化学特征研究

正确认识降水中的化学组分是评价酸雨和大气环境质量的重要途径，降水中低分子有机酸的研究是认识C、H、O等元素生物地球化学循环和酸雨成因的重要内容。贵州省遵义市作为我国酸雨高发地区，是降水化学组成尤其是低分子有机酸地球化学循环研究的典型区域。我们在遵义市进行了为期一年(2006年5月~2007年4月)的降水采集(共76个样品)，对pH值、电导率和主要的阴离子(包括有机和无机)、阳离子进行了测定，并进行了分析和讨论。 (1) pH和电导率的雨量加权平均值分别为4.11(范围：2.30~ 6.04)和62.10 μs•cm-1 (范围：6.60 ~ 1630.00 μs•cm-1)，酸雨频率高达93.2%，pH存在着显著的季节变化，其中冬季pH值最低，表明遵义市酸雨污染较为严重，冬季为最。 (2) 遵义市监测期间离子浓度的大小顺序为SO42-> Ca2+> H+> NH4+> NO3-> Cl-> F->HCOO-> Mg2+> K+> CH3COO-> Na+> (COO)22-> PO43-> NO2-，其中SO42-、Ca2+、H+、NH4+、NO3-是最主要离子，浓度分别为148.15 μmol•L-1、81.89 μmol•L-1、77.74 μmol•L-1、43.80 μmol•L-1和31.50μmol•L-1，它们分别占离子总量的31.97%、17.67%、16.78%、9.45%和6.54%；遵义市大气降水中主要的致酸物质是SO42-和NO3-，主要的缓冲物质是Ca2+和NH4+，大气污染类型属硫酸钙型。相对酸度和中和因子结果表明降水中仅有77%的降水酸度被碱性物质(以Ca2+和NH4+为主)中和；因子分析中H+、NO3-、nss-SO42-(非海源性硫酸根)、NH4+归为一组，再次表明SO42-和NO3-对降水酸度的重要贡献。富集系数和源的贡献分析表明，SO42-和NO3-主要来自人为活动的贡献，SO42-来源主要包括工业、民用的燃煤燃烧释放的SO2，NO3-主要是遵义市电厂和其它工厂向大气中排放的NOx的化学转化而成。Ca2+主要来自于遵义市的土壤及水泥厂等的排放；Mg2+主要来自陆源输入，部分来自海水的贡献。氮肥生产、大面积农田化肥的使用以及生物排放源很可能是该地区降水中NH4+的主要污染源。值得注意的是，作为海盐性离子的Cl-，在遵义市降水中重要的部分还是人为活动，主要是遵义工厂(如碱厂和钛厂)向大气中排放的HCl和Cl2转化而成。无机离子浓度的季节变化表明，对于遵义市，需要逐步改变能源结构尤其是冬季工业、居民燃煤的使用，才能有效地改善遵义市当前的环境污染。 (3) 遵义市降水中含量较高的常见有机酸是[HCOO-]T、[CH3COO-]T和[(COO)22-]T，它们的雨量加权平均值各为9.29 μmol•L -1、6.47 μmol•L-1和5.06 μmol•L-1；遵义市区降水中有机酸总浓度为22.28 μmol•L-1，占阴离子总量的9.39 %；遵义市降水中四季的有机酸浓度由高到低分别为：春季>冬季>秋季>夏季。以上结果表明，遵义市的有机酸是降水中的重要组成部分，其浓度存在明显的季节性变化。在一次降雨事件中，有机酸的浓度一般随降雨时间的延长而降低，但在降雨中后期有时会出现上升的现象，表明有机酸主要来自云下淋滤作用，少数情况下来自大气远距离的传输。 (4) 相关性分析发现甲酸和乙酸具有强烈的正相关(r= 0.86)，表明甲酸和乙酸具有共同的来源。有机酸与降水中的主要无机离子NO3-、nss-SO42-、K+、Na+、Ca2+等存在着中度相关，表明有机酸的来源与人为活动有着重要的关系。应用气液平衡的原理，提出了降水中甲酸、乙酸比值(F/A)aq的有机酸来源判定方法。发现遵义降水中的有机酸春季和冬季主要来自人类活动的释放，其中春季主要来自遵义市南郊的工业污染，由南方水汽(占春季总量的54%)将其污染物传输至遵义市中心城区，冬季主要是大量燃煤的燃烧释放；夏季和秋季则主要来自植物的释放，其中秋季中的部分有机酸也受到华中和华东地区(其气团占秋季总量的45%)的远距离影响。而遵义市区的山间盆地地形、高湿度、高静风率和低风速、以尘埃为主的大气污染物和有机酸的短生命周期(几小时~几天)为有机酸来源于当地创造了有利条件。 (5) 根据热力学平衡计算新方法，发现遵义市pH≤5的降水中甲酸和乙酸对自由酸度的贡献分别为14.79% (范围：0.42~91.14%)、3.66% (范围：0.02~31.55%)。对比显示，遵义市的有机酸贡献量低于边远地区，主要由于遵义市降水的低pH值和高无机酸度所致。在春、夏、秋、冬季节，降水中的有机酸对自由酸度的平均贡献值分别为31.95%、26.16%、8.02%、11.17%，表明有机酸酸度有着明显的季节性差异，春季有机酸的高贡献量主要受降水中的有机酸高含量、低水温和高pH值的共同作用，夏季受高pH值的影响，而秋季和冬季的低贡献量主要受降水的低pH值所控制。 (6) 在遵义市的沉降通量中，无机离子的湿沉降通量占所有离子湿沉降总量的94%，并存在明显的季节性变化。SO42-、Ca2+、H+、NH4+、NO3-为最主要的贡献者，分别为90.1、49.8、47.3、26.0和19.2 mmol•m-2•yr-1。对比显示，SO42-、Ca2+、H+的沉降量均属于我国的高值区，而NO3-的沉降量属于我国中值区，NH4+的沉降量属我国低值水平。营养元素总无机氮TIN(TIN= NH4+ -N+ NO3- -N+ NO2- -N)的湿沉降总量为45.7 mmol•m-2•yr-1，其中NH4+和NO3-分别占TIN的57.0%和41.9%，遵义地区高TIN值当地氮肥的施用量和工业NOx的释放量密不可分；营养元素P的沉降量为1.97 mmol•m-2•yr-1，由于P的来源较少，促使P的湿沉降通量较低。有机酸占湿沉降总量的6%，其四季的湿沉降量顺序由高到低依次为：春>秋>冬>夏，这是有机离子的浓度和四季的降雨量共同作用的结果。根据气液平衡理论可知，挥发性有机酸(HCOO-、CH3COO-和CH3CH2COO-)的干沉降量占总沉降量的47.2%，表明遵义市有机酸沉降方式包括干湿沉降两种。因此在研究遵义市的污染物尤其是有机酸类对生态系统和城市建设的影响时，有必要同时收集气样和水样。