【作者】 李丹；

【导师】 邓兵；

【作者基本信息】 华东师范大学 ， 海洋化学， 2009， 硕士

【摘要】 河流水体水化学特征不仅可以反映流域岩石化学风化的强弱和类型,其在一定程度上还能反映水体的环境质量状况;而岩石化学风化作用是研究海陆物质循环和全球气候变化的重要环节。基于此,论文主要研究内容包括4大部分:一,探讨了中国东部主要入海河流水化学特征,通过河流水化学特征分析了其主要的控制因素,讨论了流域岩石的主要岩石风化类型;二,对长江流域从其干流、支流、河口、湖泊、水库以及流域降水的水化学特征入手,分析了其间的差异,探讨了他们水化学特征之间的影响与关联,估算了大气降水对主要离子的贡献率,计算了化学风化率与大气二氧化碳消耗量;三,通过近年来长江河口水化学组分观测,分析了近年来长江水化学组分与入海通量的变化趋势及其影响因素,并结合水文年鉴上收集到的相关数据,探讨了长江近50年来水化学特征与入海通量的变化趋势,并用河流水质演化概念模式（Meybeck）对其现阶段及未来水质变化进行了分析;四,结合各大河流水文资料,从已有的水化学资料入手,对各大海区输入河流溶解质和DIC输送通量进行了估算。具体获得如下一些初步认识:（1）黄河、海河、滦河水体矿化度很高,约为世界河流平均矿化度的3～6倍,其水化学组成以Na⁺、Ca²⁺、Cl^-、SO₄^2-和HCO₃^-为主,主要受蒸发岩风化和人类活动影响;鸭绿江受降雨充沛、植被发育的影响,风化作用较弱,水体矿化度与世界平均水平相当;长江水体矿化度为世界河流平均矿化度的2倍之多,主要化学组成以Ca²⁺、SO₄^2-和HCO₃^-为主,是典型的碳酸盐风化类型,沿江工农业污染对长江河水化学组成影响较大,主要对SO₄^2-和TN;浙江沿海河流,钱塘江水体矿化度略高于世界平均水平,低于长江,灵江和瓯江水体矿化度低于世界平均水平,而椒江、甬江和鳌江水体矿化度变化复杂,变化幅度大,可能是外来溶解态物质的影响;大气降水对浙江沿海河流水体中Na⁺和Cl^-的贡献率较高,岩石风化则以硅酸盐风化为主,浙江沿海河流化学风化率均高于世界平均水平,且各大河流均有差异,其主要因素是地势起伏和人类活动,其次可能是森林覆盖率、耕地面积比率和水土流失比率;浙江诸河每年平均消耗大气CO₂约26.69×10⁶mol;海南诸河属降水控制类型,由于全岛降雨量大,河水矿化度远低于世界平均水平,大气降水对河流水体中SO₄^2-、Na⁺和Cl^-的贡献率较高;全岛岩石以硅酸盐风化为主。据估算,南渡江流域化学风化率与万泉河流域相当,高于世界平均水平,南渡江CO₂消耗总量约为万泉河流域的7.5倍,占全岛二氧化碳消耗总量的60.52%。（2）长江上游水库水体矿化度远高于长江干流,主要受蒸发浓缩作用控制,长江河口、洞庭湖、鄱阳湖水体矿化度均小于长江干流,由于洞庭湖受矿化度较小的地下水补给,据估算,2008年1月,东洞庭湖地下水补给量最大,达7.35×10⁸m³,其次是西洞庭,达2.79×10⁸m³,南洞庭地下水补给量为1.36×10⁸m³,其补给量大小与湖泊各区分布的面积相关;长江干流SO₄^2-浓度从上至下有逐渐增加的趋势,主要受到工业污染排放影响,TN与Cl^-浓度也有相同变化趋势,但分别受到农业活动与循环盐的贡献,大气降水对长江上游和下游水体贡献率大于中游;海盐校正后,计算得到长江流域化学风化率和大气二氧化碳消耗总量,研究发现:长江流域各分区化学风化率均高于世界平均水平,且上游强于下游,最小为中游;大气CO₂消耗量则是中游大于上游,下游最小,分别为上游达338.23×10⁹mol/yr,中游为385.79×10⁹mol/yr,下游为223.24×10⁹mol/yr,长江全流域CO₂消耗总量占世界河流CO₂消耗总量的4.5%;各支流化学风化率表现为上游强于下游,最小为中游;支流中CO₂消耗量最少的为江西修水,赣江次之;（3）长江河口水体主要离了浓度与径流呈现很好负相关关系,季节变化明显,但主离子浓度季节差异小于径流量的季节差异;河口水体中K⁺,Na⁺,Ca²⁺,Mg²⁺,Cl^-,SO₄^2-,NO₃^-,总硬度/总碱度有上升趋势,尤其以SO₄^2-和总硬度/总碱度的上升趋势显著,SiO₃^2-,HCO₃^-则表现出下降趋势。引起近年来长江口水体主离子浓度变化的影响因素为工业排放、环境酸化、循环盐和三峡蓄水。近年来入海溶解质量有减少趋势,DIC输送量基本没有变化;近五十年来长江水体SiO₃^2-、HCO₃^-浓度下降,NO₃^-、SO₄^2-浓度上升,入海径流量50年来变化不明显,TN输送量呈现较为明显的增加趋势,DIC输送量整体上呈现减少趋势,但变化很小,入海SiO₃^2-总量呈现递减趋势。（4）我国河流水体矿化度北部和中部大多高于世界河流平均水平,整体表现出往南有偏小的趋势;化学风化率则表现为北部最小,南部其次,中部最大;长江流域CO₂消耗率最高,海南岛各河流流域最小,前者为后者的10倍之多;中国东部河流流域每年消耗大气CO₂总量为1569.5×10⁹mol/yr,约占世界总量的7.47%。据估算,每年输入黄海、渤海、东海、南海的总水量达15923×10⁸m³,入海沙量达17463.6万吨,入海总溶解质量达263.95×10⁶t,入海DIC量达127.45×10⁶t,但各海区分配比例不一致,基本上入海水量、溶解质量、DIC量分配比例较为一致,而沙量分配比例则不同。更多还原

【Abstract】 The hydro-chemical characteristics is not only a manifestation of the extent and the style of the chemical weathering,but also a reflection of environmental quality status of water body;The chemical weathering is a very important part of material geochemistry cycle and the global climate change.Basin on that,there are four part in this thesis,the first,it discuss the hydro-chemical characteristics of the rivers in the east of China, analyses the affection factor and the main style of chemical weathering;the second,it shows the differences of hydro-chemical characteristics about the given main-channel, the branches,the estuary,the lake,the reservoir and the rain water in Yangtze river basin, analyses the affection and the connection.Basin on the concentration of main ions about the given main-channel,the branches and the rain water,we estimated the contribution of the rain water to the given main-channel and the branches.From the PCA result and the contribution of the rain water,we calculate the chemical weathering rate and CO₂ consumption;the third,it analyses the changes of hydro-chemical characteristics and the flux of Yangtze river in recent years and last 50 years;the fourth,it estimates the flux of rivers transport to the seas.The following conclusions have been drawn:（1）Yellow River,Hai River,Luan River have a high TDS,they are the 3～6 times than the mean value of the world rivers,the major ions are Na⁺、Ca²⁺、Cl^-、SO₄^2- and HCO₃^-,the evaporate weathering and the human activities are the main affection;Yalv River has the weak weathering and the equivalent TDS with the mean value of the World Rivers,that effected by enough rainfall and the luxuriated plant;the TDS of Yangtze River is 2 times more than the mean value of the world rivers,the major ions are Ca²⁺、SO₄^2- and HCO₃^-,carbonate weathering is the main type in this basin,except that,the concentration of SO₄^2- and TN is effected by the pollution of industry and agriculture;the river in Zhejiang Province,the TDS of Qiantang River is a litter higher than the the mean value of the world rivers,but it lower than Yangtze River,Ling River and Ou River both lower than the mean value of the world rivers,the concentration of TDS in Jiao River, Yong River and Ao River have a large changes extent,and the changes is complicated, the possible reason is that they have a variable adventitious dissolved matter.The contribution of the rain water is important,especially for the Na⁺ and Cl^-,in their basins, silicate weathering is the main style,the seven Rivers have different CDR,and the effects for it are human activities and geology element,then with the forest coverage rate,plough area and the PDR.It is estimated that there is 26.69×10⁶mol CO₂ consumed;the rivers in Hainan Province is controlled by the rainfall,they have low TDS concentration.The contribution of the rain water is high,especially the SO₄^2-、Na⁺ and Cl^-.Silicate weathering is the main style.In Hainan Island,the CDR in Wanquan River basin and Nandu River basin are stronger than the average in the whole island,the both have litter difference.The CO₂ consumption in Nandu River basin is 7.5 times than Wanquan River basin,its proportion in the whole island is 60.52%.（2）The TDS of the reservoir is higher than the given main-channel,but the branches, the estuary and the lakes are lower than the given main-channel,it is because that the Dongting Lake has a contribution from Groundwater with a low TDS.It is estimated that there are 7.35×10⁸m³ groundwater to the east Dongting Lake,about 2.79×10⁸m³ groundwater to the west Dongting Lake,about 1.36×10⁸m³ groundwater to the south Dongting Lake,×10⁸m³,the supplied quantity is related to the area;the concentration of SO₄^2- has a increasing trend from up to down in downstream,it is effected by the pollution of industry,the concentration of TN and Cl^- have the same trend,they effected by agriculture pollution and circulation salt respectively,the contribution of the rain water in upstream and downstream is bigger than the mid-stream,rectify the concentration of the main ions,we calculate the chemical weathering rate and CO₂ consumption in Yangtze River basin:the chemical weathering rate stronger than the average of the world in the whole river basin,the upstream basin is stronger than the downstream basin and the weakest is mid-stream basin.The CO₂ consumption in upstream basin is 338.23×10⁹mol/yr,the mid-stream basin is 385.79×10⁹mol/yr,the downstream basin is 223.24×10⁹mol/yr.Yangtze River basin,its proportion in the world is 4.5%.The chemical weathering rate in all branches have the same result,in upstream is stronger than the downstream,and the weakest is the mid-stream;（3）The concentration of main ions varies clearly in different seasons,but the difference is less clearly than the discharge;there is a persistently increasing trend has been observed in the concentrations of K⁺,Na⁺,Ca²⁺,Mg²⁺,Cl^-,NO₃^-,SO₄^2- and the ratio of hardness/ alkalinity,especially the concentration of SO₄^2- and the ratio of hardness/alkalinity have a more obvious increasing trend;in contrast the concentration of SiO₃^2- and HCO₃^- show a decreasing trend.The changes of major ions mainly result from the environment acidification,the pollution emissions by human,the cyclic salt from sea and the preserved effect by reservoirs establishments etc.in recent years,the Flux of the total dissolved solutes has a decreasing trend,the flux of DIC has little changes;in last 50 years,the concentration of SiO₃^2-and HCO₃^- have decreasing trend,but NO₃^- and SO₄^2- have increasing trend,the discharge has no obvious changes,the flux of TN has obvious increasing trend,but the flux of DIC and the SiO₃^2- show a decreasing trend.（4）The total dissolved concentration of rivers in East China has a decreasing trend from north to south.In north and mid-part,there are most of rivers have a higher TDS than the average value of the world.The CDR in north is weakest,and then is the south, the middle is strongest.The CO₂ consumed is about 1569.5×10⁹mol/yr in East China.It is estimated that,the seas（The East Sea,The Yellow Sea,The South Sea and The Bo Sea） accept the water from the rivers is about 15923×10⁸m³,the total solid mass is about 17463.6×10⁴t,the total dissolved solutes is about 127.45×10⁶t,but the distribution to the four sea is inequable,but the distribution proportion of discharge,the total dissolved solutes,the quantity of DIC in each sea are similar,the total solid mass is different.更多还原