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豫东平原高氟水赋存形态及形成机理研究

The Study of the Storing Form and the Formation Mechanism of the High-fluorine Water in Eastern Plain

【作者】 曹金亮

【导师】 徐恒力;

【作者基本信息】 中国地质大学 , 水文学及水资源, 2013, 博士

【摘要】 氟是人生长发育不可或缺的化学组分,人体几乎所有的各种器官内均含有氟,但人体内的氟绝大部分分布在硬组织骨骼和牙齿中,两者约占人体总含氟量的90%以上。但人对氟的最佳的摄入量仅在一个很窄的范围之内,当氟的浓度过大时,会产生矿化过度或异位矿化的病理现象,造成氟中毒,称为地方性氟中毒(简称地氟病,EFD)。地氟病广泛分布于世界50多个国家和地区,我国地氟病病区分布范围遍及全国29个省、区、市,全国有病区县1226个,病区村15万多个,病区人口超过1亿人。为降低发病率、切实提高人民的健康水平,国家和各级地方政府投入了大量的人力物力,对地氟病的成因进行探讨,采取多种方法降氟,但迄今为止效果并不理想,究其原因在于对于人体摄氟的主要来源—地下水中氟的迁移与富集机理还缺乏更深入、科学的认识。本文以地氟病高发的河南省豫东平原区(集中于周口地区)为例,在野外调查、取样测试分析的基础上,以科学发展观和地球系统科学理论为指导,运用层级理论和地下水系统理论将区域地质环境背景、局部地下水流动系统与取样点水化学环境三个不同空间尺度紧密联系,阐明氟在地下水中的迁移与聚集过程和特征;运用开放的非线性系统协同理论,探讨在多化学组分的天然条件下,氟在地下水中的聚集效应及高氟水的形成机理;提出水化学相图分析法,更深入地揭示了高氟水形成的化学机理;从生态地质学的角度研究人工构建植物根群坝以降低浅表环境氟背景值的可行性。论文得出以下结论:1.不同的水化学组分划分为系统内部要素不同的组合形态,简称为组态。系统所形成的稳定状态最终归结为不同的组态之间相互协同作用的结果。按照改进的的布罗茨基分类法进行划分,共划分出98种水化学组态。其中,CaMgNa-HSCIN、CaMgNa-HCISN. CaNaMg-HSCIN、NaMgCa-HSCI、CaNaMg-HCISN、NaMgCa-HCIS型组态出现的个数较多,分别占总数的12.64%、7.09%、6.29%、5.89%、4.41%、4.01%。在98种水化学组态中,出现高氟水的组态有62个,未出现高氟水的组态有36个,出现高氟水的组态类型占所有组态类型的63.3%,平均高氟率0.25。2.如果从水化学类型的角度进行状态组合,那么每一个水样点代表一个组态,即高氟水集中或分散规律性的特点,这种特点即为相。组态是由钙的毫克当量浓度、钠的毫克当量浓度、矿化度、pH值等状态值构成。当所有水样的状态值投在一张图上时,就形成了水化学相图。3.各相空间高氟水分布规律(1)包络线外侧的两个相空间不出现高氟水,高氟水都出现在包络线内侧的相空间。包络线内侧的6个相空间都有高氟水出现,但是出现的概率不均等。(2)在包络线内侧,上面⑥⑦⑧三个相空间要比卜面③④⑤相空间出现高氟水的概率大。(3)从③~⑤相空间以及从⑥-⑧相空间,高氟水出现的频率呈增加的趋势,而同样,矿化度也是呈增加的趋势。4.高氟水分布规律的化学机理(1)在包络线外侧的相空间①和相空间②都不出现高氟水,但情况有所不同。在相空间②,水质具高钙低氟的特征,此相空间向Ca2+2F→CaF2↓方向进行,水中的氟以简单氟离子形态为主,都形成了CaF2沉淀。在相空间①,水质可以是高钙低钠也可以是低钙高钠或者钙钠相当,造成低氟的原因是没有主导性化学反应,其中部分氟可能以简单氟离子形态存在,其余的可能为络合物氟离子。(2)抛物线内侧的有6个相空间,可分为两个次级相空间,一个次级相空间为③~⑤,另一个次级相空间为⑥~⑧。⑥~⑧相空间出现高氟水的频率明显高于③-⑤相空间,且具有低钙高钠的特征,高氟概率分别为29.17%、63.18%、75.00%。本次级相空间水中的氟以简单氟离子为主,络合物氟离子较少(经计算位于此相空间的是化学反麻NaF→Na++F+占优),导致高氟的主导性化学反应为NaF→Na++F+,此外,由⑥~⑧相空间矿化度逐渐增高,高氟水出现的频率也逐渐增大;③-⑤相空间高氟水出现的概率分别为6.96%、29.14%、73.53%。本次级相空间内钙钠含量不确定,高氟水出现具有很大的不确定性,简单氟离子和络合物氟离子的含量难分伯仲,可能不存在主导性化学反应或者上述两种主导性化学反应的反应速率在不同的地点相差较大,从而导致高氟水出现的概率没有上部三个相空间出现的高。5.高氟地下水成因及分布的规律的多因子协同作用。认为高氟水在形成过程中不是某一个因子的作用,而是多因子的协同作用。这些因子的协同作用与区域流动系统控制着高氟地下水分布的宏观格局;不同因子之间的不同作用和局部流动系统导致高氟水分布的不均匀性:不同级别流动系统的嵌套,造成氟在垂向上的分异。6.探讨了植被生态系统降低浅层地下水氟含量的途径。生态降氟途径是根据系统理论中隔离机制的思想和生态地质学基本原理,通过各种层次的植物“根群坝”,将氟在研究区内的运动路程分解,实现氟迁移过程的化整为零、层层拦截效果,降低高氟水分布区土壤和地下水的氟含量,达到人体摄入的水和粮食中的氟含量低于国家标准的方法。7.研究区高氟地下水的赋存形态和分布规律具有以下特点:①根据水样测试和PHREEQC软件模拟结果,确定研究区内中性或偏碱性(PH值7-8.3)的深、浅层地下水中,氟的赋存形态有F-、HF、 CaF+MgF+、NaF、A1F3、FeF+等8种;②浅层地下水中简单氟阴离子及其络合物浓度F->MgF+>CaF+>NaF>AlF2+>AlF3>HF和FeF+。一般F-占F总(总氟浓度)的79.55%-96.08%,其次为MgF+、CaF+和NaF,分别占F总的2.91%-18.01%、0.16%-2.58%和0.05%-1.82%;③深层地下水中简单氟阴离子及其络合物浓度F>MgF+>CaF+>NaF>HF>AlF2->AlF3>FeF+。一般F-占F总(总氟浓度)的84.91%-99.17%,其次为MgF+、CaF+和NaF,分别占F总的0.23%-13.28%、0.05-1.75%和0.08%-0.96%;④地氟病患病率受到地下水中氟含量及其赋存形态等内在因素的影响明显,水中氟含量低患病率却较高的地区,浅层地下水主要受简单氟离子和氟镁络合物的影响,前者值域范围为0.036-3.59mg/L,后者介于0.172-0.258mg/L;深层地下水除受简单氟离子和氟镁络合物的影响和控制外,HF可能亦是致病因子之一,其中F值域范围为0.039-3.19mg/L,氟镁络合物值域范围为0.009--0.014mg/L,HF值域介于0.002mg/L-0.003mg/L之间。⑤从组态分析法和协同学方面考虑,地氟病致病因子不是单个因子所为,而是各组分相互作用之结果,某些离子的组合可能起协同作用,某些可能起拮抗作用,本文通过对PHREEQC软件模拟结果分析,认为患病概率的增加,可能是简单氟离子与氟镁络合物、HF之间存在协同作用所致,其具体作用原理、方式还有待于毒理学与临床医学的进一步证明。本文的创新之处在于:高氟地下水形成机理的“组态分析法”和“水化学相图法”。在微观尺度运用多态理论研究方法和协同学观点,首次提出了“相图分析法”和“组态分析法”,对高氟地下水的形成机理有了更为明确的认识。组态分析法是基于协同学理论提出的,所谓“组态”是指水文地球化学微环境中,各种化学组分按相对恒定的比例组合在一起,形成的多状态组合。据此理论将除了F以外的其它指标按照改进的布罗茨基分类法进行水型划分,共划分出98种水型,得出结论:①氟离子可以存在于多种地下水组态中;②氟离子浓度在不同组态中会有一定差异;③在具有相同氟离子浓度的不同水化学微环境中,简单氟离子与络合形式的氟离子所占的比例是不同的:④各水化学微环境的氟浓度和离子的不同比值,可以由主导性的化学反应决定,也可以不存在主导性的化学反应,而是多个化学过程耦合的结果,如多级化学反应。水化学相图分析法的实质是把每一个水样视为一个组态。组态是由钙的毫克当量浓度、钠的毫克当量浓度、矿化度、pH值等状态值构成。本次工作测试的所有水样都落在图中①-⑧共8个相空间内。通过研究解决了如下问题:①在何种水化学微环境中可能出现高氟水、中低氟水,以及它们出现的概率,何种化学背景下高氟水的出现具有明显的随机性;②导致高氟水和中低氟水高发是否由主导性化学反应控制,这些主导分别是什么;③在pH值为6.7-8.4时,地下水中的氟在哪些微环境中以简单离子为主,哪些微环境中简单氟离子和络合物氟离子共存。

【Abstract】 Fluorine is an essential chemical composition to people, of which almost all of the organs need fluorid, and the most part of fluorine is distributed in hard tissues such as bones and teeth, account for about90%of the total fluoride in human body. But the best intake of fluoride ranges in a very narrow scope. When the fluorine concentration is much too high, pathological phenomena as excessive mineralization or ectopic mineralization will happen, and this will cause fluorosis, called endemic fluorine poisoning (endemic fluorosis for short, EFD). EFD is widely distributed in more than50countries and regions all over the world. In our country, the fluorine endemic area distribute throughout29provinces, autonomous regions and municipalities, we have1226sick districts and counties and more than150,000sick villages, the population of the endemic area is more than100million people.To reduce the morbidity and improve people’s health level, state and the local governments invested a lot of manpower and material resources and discussed the causes of EFD, a variety of methods decreasing fluorine has been taken, but the effect is not ideal so far. The reason is the lack of the deep and scientific understanding the migration and enrichment of the fluorine in groundwater which is the main source of our body.We take the high incidence area-the eastern plain in Henan province as an example in this paper. On the basis of field investigation, sampling test and analysis, guided by the scientific outlook on development and the earth system science theory, using the hierarchy theory and the groundwater system theory, three different spatial scales-the regional geological environment background, the local groundwater flow systems and the water chemical environment of the sampling points-were linked closely and the migration and accumulation process and characteristics of F in groundwater were expounded. Using the open nonlinear system synergy theory, discussed the aggregation effect of fluorine in groundwater and the formation mechanism of high fluoride water in natural conditions of multi-chemical components. Hydrochemistry phase diagram analytical method is put forward, which can further reveal the chemical mechanism of the formation of high fluoride water. From the perspective of ecological geology, the feasibility of building the artificial plant root group dam which is help to reduce the superficial environmental fluoride background value was discussed. We get the following conclusions in this study:1. The different water chemistry components are divided into different combinations of system elements, called the configuration. Steady state formed by the system ultimately comes down to the result of the synergy between different configurations. According to the improved Brodsky classification, chemistry components were divided into98kinds of hydrated state. Among which, the configuration type of CaMgNa-HSCIN, CaMgNa-HCISN, CaNaMg-HSCIN, NaMgCa-HSCI, CaNaMg-HCISN, NaMgCa-HCIS seem to be more, account for12.64%、7.09%、6.29%、5.89%、4.41%、4.01%of the total respectively. Among the98kinds of hydrochemistry configurations,62configurations show high fluoride water, the other36configurations are not high fluoride water, high fluoride water configuration type account for63.3%, an average high fluoride rate is0.25.2. If combine from the angle of the type of hydrochemical, every point is a different configuration and each sample point represents a configuration, namely the high fluoride water concentrate or disperse regularly, this characteristic means the phase. Configuration is made up of status values, such as calcium mg equivalent concentration, sodium mg equivalent concentration, salinity, pH values. When the status values of all the samles are put into a picture, the water chemical phase diagram formed.3.The distribution regularity of the high-F groundwater in various phase spaces(1) The two phase spaces outside the envelope line don’t appear high-F groundwater, high fluoride water appears in the phase spaces inside envelope line. High fluoride water appears in the six phase spaces inside the envelope line, but the probability is not equal.(2) In the inside of the envelope, the probability of high fluoride water of the three phase spaces above(⑥⑦⑧) is larger than the phase spaces below(③④⑤).(3) From phase space③to⑤and from⑥to⑧hase space, the frequency of high fluoride water shows an increasing trend, and as well, salinity is also shows a trend of increase.4.Chemical mechanism of the distribution of high fluoride water(1) The phase space①and space②outside of the envelope do not appear high fluoride water, but things are different. In the phase space②, the water has the feature of high calcium and low fluorine, the phase space has the reaction that the fluoride in water given priority to simple fluorine ion have come into the CaF2precipitation. In phase space①, the water can be high calcium and low sodium or high sodium and low calcium or of about the same calcium and sodium, there is no dominant chemical reaction causes the low fluorine. Some of the fluoride may be exist as simple fluoride ion and the rest may be complex fluorine ion.(2) There are six phase spaces inside the parabola. These spaces can be divided into two secondary phase spaces, the one contains the space③to⑤, the other contains the space⑥to⑧. The space⑥to⑧ave better frequency of the occurrence of high floride water than the space③to⑤significantly, and have the characteristic of low calcium and high sodium, the probability of high fluoride water were29.17%,63.18%and75.00%respectively. Fluoride in this secondary phase is given priority to simple fluorine ion and low in complex fluorine ion (via calculating, the chemical reaction of NaF→Na+F+have the preponderance), which lead the dominant chemical reaction of high-F to be NaF→Na+F+.In addition, salinity of the phase space⑥to⑧ncrease gradually and the probabilities of the occurrence of high fluoride water also increase gradually.The probabilities of the occurrence of high fluoride water in the apace③to⑧were6.96%,29.14%and73.53%respectively. In this secondary phase space, the sodium content is not sure, the occurrence of high fluoride water has a great deal of uncertainty, and the content of simple fluorine ion and complex fluorine ion are almost the same. Maybe there is no dominant chemical reaction or the rate of the two dominant chemical reaction above have a large differences under two different locations, which leads to the probability of high fluoride water not as high as three phase spaces discussed above.5. The multi-factor synergism in the causes and distribution of high fluoride groundwater. It is insisted that the formation process of high fluoride groundwater is not affected by a certain one factor but the synergy of many factors. The synergy of these factors and regional flow system control the macroscopic distribution pattern of high fluoride groundwater; the different effects between different factors and local flow systems lead to non-uniformity of high fluoride water distribution; the nested structure between different level flow systems cause vertical differentiation of fluorine distribution.6. Discussed how to reduce the fluoride content of shallow groundwater by vegetation ecosystem.Ecological method is a method based on the isolation mechanism of the system theory and the basic principle of ecological geology, through various levels of "plant root group dam", dicompose the fluoride movement in the study area, and by breaking up the fluoride migration process and intercepting fluoride layer by layer, reduce the distribution area of high fluoride in groundwater and soil, make the human intake of fluoride content in water and food lower than the national standard.7. Characteristics of the storing form and distribution of high fluoride groundwater in the study area:①According to the results of sample testing and simulation of the PHREEQC software, it is confirmed that in the neutral or partial alkaline (PH7-8.3) groundwater in the deep and shallow aquifer of the study area, fluorine exists as F-, HF, CaF+, MgF+, NaF, A1F2+, AIF3, FeF+8modes.②Simple fluoride anion and its complex concentration in shallow groundwater is:F-> MgF+> CaF+> NaF> AlF2+> A1F3> HF and FeF+. Generally, F-accounted for79.55%to96.08%of the total F (total fluorine concentration), followed by MgF+, CaF+and NaF, accounted for2.91%to18.01%,0.16%to2.58%and0.16%to18.01%of the total F respectively;③Arrange the concentrations of simple fluorine ion and its complex compounds in the deep groundwater from big to amall:F-> MgF+> CaF+> NaF> HF> AlF2+> AIF3> FeF+. Generally, F-accounted for84.91%to99.17%of the total F, followed by MgF+, CaF+and NaF, accounted for0.23%to13.28%,0.05to1.75%and0.08%to0.96%of the total F;④The morbidity of EFD is affected by the internal factors significantly, like fluorine content in groundwater and its storing form. As for the area with low fluorine content and high morbidity, its shallow groundwater is mainly affected by simple fluorine ion and fluoride magnesium complex compound, the former range from0.036to3.59mg/L, the later range from0.172to0.258mg/L; Deep groundwater is not only affected and controlled by the simple fluorine ion and fluoride magnesium complex compound, it may also affected by HF. In this condition, the concentration of F-range from0.039to3.19mg/L, fluoride magnesium complex compound range from0.009to0.014mg/L, HF range from0.002to0.003mg/L.The innovation of this paper is:The "configuration analysis" and "water chemical phase diagram method" for the formation mechanism of high fluoride groundwater.In microcosmic scale, using the polymorphic methods and synergetics theory, put forward the "configuration analysis" and "water chemical phase diagram method" for the first time, and have a more clear understanding of the formation mechanism of high fluoride groundwater.Configuration analysis method is proposed based on synergetics theory. The "configuration" refers to the hydrogeochemical environments, all kinds of the chemical components conmbine in a relatively constant proportion, forming the combined state. According to this theory, indicators except F-1were divided into98kinds of water types according to the improved Brodsky classification, drawing the conclusion:①fluorine ion can exist in a variety of groundwater configuration;②the fluoride ion concentration have certain differences in different configurations;③in the different water chemical microenvironment containing the same fluoride ion concentration, the proportions of simple fluorine ion and complex fluorine ion are different;④the fluorine ion concentration and the different ratio between ions of each water chemical microenvironment, can be determined by the dominant chemical reaction, also can be the result of several coupling chemical processes when there’s no dominant chemical reaction, such as the multistage chemical reaction.The essence of water chemical phase diagram analysis method is regarding each sample as a configuration. Configuration is made up of calcium milligram equivalent concentration, sodium milligram equivalent concentration, salinity, pH values and so on. All the samples tested in this study can be put in the8phase spaces in the picture. The following problems have been solved in this study:①the high fluoride water, low fluorine water may occur in what water chemical microenvironment, and the probabilities, and in what chemical background, high fluoride water has obvious randomness;②from non-beryl water and lead to a high incidence of low fluorine water is controlled by dominant chemical reaction, what are the dominant;③for the pH value of6.7-8.4, where fluoride in groundwater given priority to simple ion in microenvironments, in which microenvironment simple fluorine ion coexist with complex fluorine ion.

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