In this study the F
$^-$
ion concentration levels of
209 well water samples belonging to previous construction analysis (CA) and a
total of 121 well water samples belonging to the current study (CS) in
Al-Butana region of Central Sudan were investigated and located (mapped) using
the geographical information system (GIS). The GIS-map indicates that the
majority of F
$^-$
levels ranging between 0.5 and 1.5 mg/l
dominates the northern part of the study area and the levels below 0.5 mg/l
dominates the southern part of the study area whereas the levels above 1.5 mg/l
are limited and are scattered, randomly, throughout the study area.
The results obtained revealed considerable spatial variations in the
occurrence of fluoride even within the same community area,
F
$^-$
levels ranging between 0.0 and 6 mg/l were found in
boreholes drilled in Rufaa' Town. The majority of the investigated boreholes
viz., 39.71% and 42.98% were found having F
$^-$
levels below
0.5 mg/l whereas only 0.96% and 3.3% were found beyond the level of 2.5 mg/l,
for the CA and CS, respectively. The wide range of F
$^-$
levels (from 0 to 7 mg/l in the CA and from 0 to 2.6 mg/l in the CS) revealed
the variability in the spatial distribution of F
$^-$
in the
study area. 94.26% and 88.43% of the groundwater samples were found below the
maximum recommended level of 1.5 mg/l set for F¨C in drinking water by each
of SSMO (2002) whereas only 5.75% and 11.58% were found in excess of this
level, for the CA and CS, respectively. The decrease in the mean value of
F
$^-$
in the investigated boreholes from 1.4 mg/l in the CA
analysis to 0.6 mg/l in the CS analysis, indicates that F¨C levels in the
investigated boreholes has the tendency to decrease during pumping. Mottled
teeth are widely observed among residents in the study area in spite of
fluoride compliancy to SSMO standards. Therefore, dental fluorosis, in the
study area, is not unlikely to occur.
