The Influential Factors And Distribution Of Groundwater Arsenic In The Typical Section Of Hetao Plain

Hetao region is a typical arsenic poisoning area in China.The area includes 19 towns,and the severity of disease is vast discrepancies.In the Hetao Plain arsenic pollution research,this study was first bring in the method of typical section according to the distribution of characteristics of high arsenic groundwater and selecting the arsenic areas.The author systematically collected groundwater and soil samples to analysis the lithofacies palaeogeography and geochemistry, carry out comparatively analysis of arsenic contaminated areas and non-arsenic-contaminated areas,summary the pattern of arsenic contaminative groundwater and study the arsenic contamination mechanism of groundwater.This study assigned three typical profiles: HangJinhou Banner-Linhe county,Wuyuan Town-XiaoZhao county in Wulate Front Bannner,Tumote left Banner-Tuoketuo county.The profiles were assigned to follow the direction of groundwater flowing.The profiles crossed two important geomorphic units,which were the piedmont alluvial diluvial plain and the Yellow River alluvial lacustrine plain(Daheihe River alluvial lacustrine plain).The south of Daqingshan was north of the profile,than run throμgh the whole Hetao Plain,finally south to the north of Yellow River.We sampled and studied in every typical geomorphic unit,uniting the geological environment and the distribution of arsenic in groundwater to obtain macroscopic analyses of a series of chemistry components, which affected the remobilization and accumulation of arsenic,in the path of ground water excreting .The item also studied the characteristics changes of arsenic and the release mechanism of high arsenic water under different geological environment.The reaserch is significant to study the formation mechanism of high arsenic groundwater in the Hetao Plain.The main research contents and results included as below:1. With the findings of three typical profiles, the authors as certain the main high arsenic distribution.2. With studying the source of arsenic in Hetao region,and unite geological, hydrological and other aspects of information,the author have drawed a conclusion that there were many reasons for the source of arsenic. 3. According to the hydrochemical materials,the author have drawed a conclusion that As³⁺ was more than As⁵⁺ in the study area.4. The test results of this item can be assumed that the arsenic and the HCO₃^- linked tightly and we can assort the high-arsenic water for HCO₃^- type water,in Hetao region.5. In high-arsenic groundwater,the presence of arsenic forms mainly were: H₃AsO₃ and HAsO₄^2-.6. The major act of arsenic migration and releasion was adsorption and desorption, and the adsorbent was clay mineral, iron oxides and iron hydroxide.