Stagnant surface water bodies (SSWBs) as an alternative water resource for the Chittagong metropolitan area of Bangladesh: physicochemical characterization in terms of water quality indices

Abstract

1The concern over ensuing fresh water scarcity has forced the developing countries to delve 2 for alternative water resources. In this study we examined the potential of stagnant surface 3 water bodies (SSWBs) as alternative fresh water resources in the densely populated 4Chittagong metropolitan area (CMPA) of Bangladesh -where there is an acute shortage of 5 urban fresh water supply. Water samples, collected at one month intervals for a period of one 6 year from 12 stations distributed over the whole metropolis. Samples were analyzed for pH, 7water temperature (WTemp), turbidity, electrical conductivity (EC), total dissolved solids, 8 total solids, total hardness, dissolved oxygen (DO), chloride, orthophosphates, ammonia, total 9 coliforms (TC) and trace metal (Cd, Cr, Cu, Pb, As and Fe) concentrations. Based on these 10 parameters different types of water quality indices (WQIs) were deduced. WQIs showed most 11 of CMPA-SSWBs as good or medium quality water bodies while none were categorized as 12 bad. Moreover, it was observed that the minimal water quality index (WQI m ), computed 13 using five parameters: WTemp, pH, DO, EC and turbidity gave reliable estimate of water 14 quality. The WQI m gave similar results in 72% of the cases compared with other WQIs which 15 were based on larger set of parameters. Based on our finding, we suggest the wider use 16 WQI m in developing countries for assessing health of SSWBs as it will minimize the 17 analytical cost to overcome the budget constraints involved in this kind of evaluations. It was 18 observed that except turbidity and TC content, all other quality parameters fluctuated within 19 the limit of World Health Organization suggested standards for drinking water. From our 20 findings we concluded that if the turbidity and TC content of water from SSWBs in CMPA 21 are taken care of, they will become good candidates as alternative water resources all round 22 the year. 23Keywords: surface water; water chemistry; water quality index; Chittagong; Urban water 24 supply 25 -3 -

Assessment of a Physicochemical Indexing Method for Evaluation of Tropical River Water Quality

“…This simple index was reported to be comparable to two other indices of 20 parameters for the assessment of water body under the influence of industrial discharge [28]; nonetheless, there is a tendency of overestimation as the parameters are assigned with similar weightage [29,30]. As observed, water quality depicted with WQI min covers a wide spectrum from Class I to Class V with index values ranging between 10 and 82.…”

Assessment of Physical-Chemical Drinking Water Quality in the Logone Valley (Chad-Cameroon)

“…Another study conducted in Ghana [5] also found concentrations of lead, uranium and boron above the World Health Organisation (WHO) Guide Values (GVs) in restricted areas. Low metallic content was observed for most water samples analysed in Bangladesh [6]. Adekunle et al [7] showed that in some rural settlements in Nigeria most of the water samples from hand-dug wells, in the residential areas near the municipal dumps, contained Pb and Cd above the WHO limits for drinking water.…”

“…Also iron and manganese can be present in surface and ground waters at levels ranging from 0.5 to 50 mg/L and from 1 μg/L to 10 mg/L, respectively [8]. Concentrations exceeding WHO GVs, respectively 0.3 mg Fe/L and 0.4 mg Mn/L, were found in Cambodia [3], Zimbabwe [9], Ghana [4,5], Cameroon [10], Pakistan [11] and Bangladesh [6]. Sharaky et al [12] observed in the groundwater in the Nile delta area concentrations of trace elements lower than the standard limits, except for iron, manganese and nickel.…”

“…They suggested that the presence of iron in these boreholes could be due to its percolation from granitic and metamorphosed rocks into groundwater. Turbidity is a typical problem of surface waters and shallow open wells, as observed in the studies done in Cameroon [14], Malawi [15], Ghana [4,5], Pakistan [11] and Bangladesh [6], but it can also affect boreholes as reported in Zimbabwe [9] and Ghana [5]. Ketchemen's work [16] on the underground waters in the far north of Cameroon showed that nitrate levels were above the standards and this high content was linked to human activities.…”

Análise físico-química da água de três poços subterrâneos no município de Mossoró-RN

“…Dessa forma é necessário preservá-la e utilizá-la racionalmente (BECKER, 2008;RAHMAN, et al, 2011;FERREIRA;ROCHA;FIGUEIREDO, 2015).…”