GIS mapping of correlation between arsenic and iron concentration of ground water of Bangladesh

Abstract

Arsenic, a toxic metal has bccome a major threat to a large number of populations of Bangladesh as this ground water has become contaminated. Excessive Iron concentration is also a problem for ground water of Bangladesh. Arsenic and Iron both are present in most of the wells. As Bangladesh is vulncrable far both the Arsenic and Iron, this made the correlation analysis more rational. GIS map of this correlation analysis will represent correlation status of each individual district of Bangladesh. Not only that, GIS maps produced in this rcscarch will give the graphical representation of correlation analysis for three different layer of wells. A 3- Dimentational water matrix was formed in this research considcring different combination of arsenic and iron concentration in three different layers of wells. This 3-Dimentional matrix gave 12 sets of data which were used for analysis and GIS mapping. The same matrix was used for every district to categorize data more specifically. It is evident from this study that a zone or belt of a region can be observed of similar correlation coefficient. From the analysis it was obscrvcd that 50.4% districts of Bangladesh showed correlation coefficient in excess of 0.4 and rest shows correlation coefficient less than 0.4. In the eastern part of Bangladesh a belt of very low correlation was observed. This analysis was performed considering only the geographic locations. The produced GIS maps and analysis results will enable some one to tentatively or statistically predict the arsenic concentration of a well by knowing the iron concentration of the same well. Data were separated as per depth variation as well. It was observed that for most of the districts Correlation coefficicnt is higher for well depth bellow SOm. Correlation coefficient tends to decrease as the depth of aquifer increases. 3 separate sets of GIS maps were produced in this research for 3 different depth layers of wells for 61 districts of Bangladesh. Data of each district were classified as per developed 3-Dimentional water matrix and analyzed for correlation. 12 different GIS maps were produced for 61 districts of Bangladesh.