Abstract:
Water Quality Index (WQI) is one of the simplest, most understandable and effective way
to determine overall quality of drinking water as well as water used for other purposes. A
study was attempted to assess the spatial variability of groundwater quality index of
Manikganj district of Bangladesh. For this purpose, 31 water samples were collected and
analyzed for potential sources and of contamination. pH, Total Dissolved Solids (TDS),
Electric Conductivity (EC), Total Hardness (TH), Total Alkalinity (TA), Iron (Fe),
Manganese (Mn), Sulphate (SO₄²-
), Chloride (Cl−
) and Turbidity were measured for
calculating WQI. Their mean values were 7.05, 313.07 mg/L, 625.62 µS/cm, 207.35 mg/L,
214.57 mg/L, 5.0 mg/L, 0.093 mg/L, 14.16 mg/L, 104.38 mg/L and 62.06 respectively. The
obtained values of WQI were distributed spatially through mapping using IDW
interpolation via ESRI ArcGIS software. These values were categorized as excellent, good,
poor, very poor, and unfit for every purposes. The WQI values ranged from 7 to 683 with
an average value of 134.19. Among the 31 samples, 29.03% were excellent quality, 38.71%
were good quality, 9.67% poor quality, 12.9% very poor and 9.67% were unfit for all
purposes. The Kaiser–Meyer–Olkin test was 0.747 confirming that the dataset was
sufficient for component analysis. The entire dataset could be represented by two
components which accounted for 63.53% of the total variance of the dataset. Through PCA
the influential contaminants came to light informing that naturally occurring Fe and Mn
contaminations resulted in most of the pollution. Through this study, it can be proved that
Spatial mapping and PCA are effective tools for determining ground water quality. The
results of this study can be used to improve the current water quality situation of Manikganj
district and ensure higher quality water resources for the citizens of this district.
