The Groundwater Circle II of the Bangladesh Water Development Board (BWDB) has a national network of some 120 water quality monitoring boreholes that have been sampled twice per year, normally once each in the dry and wet seasons, for more than a decade.
A total of 113 of these sites were sampled specifically for this survey mostly in July 1998. A few sites were sampled from the west of the country in summer 1999.
The aims of the survey were to provide reliable arsenic data for the Groundwater Circle of the BWDB since they had no arsenic results for their monitoring sites. The opportunity was also used to measure a number of additional inorganic parameters, including a number of anions.
All analyses were carried out in the BGS laboratories.
Where possible, the class limits used in the maps are the same as those used for the DPHE/BGS National Hydrochemical Survey except where there is no corresponding map and for those maps which include '(health)' in their title. The class limits for these latter maps are more closely aligned to health criteria, e.g. WHO Guideline Values (as at 2001). Where no corresponding map exists, the class limits are based on rounded quartile values from the dataset.
The maps are in Adobe Acrobat PDF format, each file is less than 1 MB.
Contact Dr Pauline Smedley for further information