Abstract:
Water quality is determined by physical, chemical and microbiological properties of water.
The quality of water degrade through pollution from point and non-point sources. Water
quality degradation is one of the major environmental problems of these days. The study was
conducted to evaluate the physico-chemical parameters of groundwater quality for drinking
and irrigation suitability and to assess the potential pollution risk of groundwater in Botor
Tolay district, Jimma Zone, Oromiya National Regional State, Ethiopia. A total of 16 samples
were collected from borehole, shallow well, hand dug well and protected springs by
representative sampling technique and analyzed for physical and chemical parameters.
Electric conductivity, sodium absorption ratio, magnesium hazard, residual sodium carbonate
and kelly ratio were evaluated for irrigation suitability assessment. Potential pollution risk of
groundwater samples were assessed using D8 flow direction algorithm. The analyzed data was
presented by using table, graphs, piper diagram and figures and were compared with WHO
guideline value for drinking suitability. The result showed that for all the groundwater samples
the concentration of pH, TH, CO3
-2
, Cl- NO3
-
and SO4
-2 were below the recommended WHO
value which were suitable for drinking in terms of these parameters. For most of the
groundwater samples the concentration of EC, TDS, TA, Mg+2
, Na+2, K+2
, Ca+2, F –
and Fe+2
were found below the WHO standards thus, suitable for drinking purpose whereas the obtained
value of Mn+2
, turbidity and temperature of all the groundwater samples were exceeds the limit
of WHO standards which were not suitable for drinking purpose. Interpretation of all physico chemical parameters were carried out using AquaChem software (Version 2014.2), Microsoft
excel (Version 2013) and SPSS (Version 20). All groundwater samples were found suitable for
irrigation water according to EC and SAR whereas only 50% water sample were suitable
based on MH and KR. According to RSC all groundwater samples were suitable for irrigation
water except sample S4, S7, S9 and S12. The potential pollution risk assessment of
groundwater samples were classified as no, low, medium and high with sample number of 8,
3, 4, and 1, respectively
