V2I9P14

Analysis, Simulation and Cross Examination of the Spatio-Temporal Differences of Groundwater Quality in the Eastern Part of Nigeria

Ikpa P. N.^1*, Uzoukwu C. S.¹, Uzoh U. E.¹, Udoha C. L.¹, Nwokorobia G. C.¹, Njoku  K. O.¹, Ogbonna N. S. M.¹, Igbojiaku A.U.¹

Abstract

This study dealt with the XG boost model in analyzing the spatio-temporal variations of groundwater quality parameters from different hydrological formations of Imo State, Nigeria.  Several iterative processes were conducted using this model, from the values generated from the processes as discussed below. On a monthly basis for a period of one year, 72 groundwater samples were collected from 6 hydrological formations of Imo State and were analyzed for 22 physiochemical parameters: pH, electrical conductivity, total dissolved solid, total suspended solid, total solid, dissolved Oxygen, Biochemical Oxygen Demand, (BOD), Chemical Oxygen Demand, Nitrate, Bicarbonate, (HCO3)Potassium (K),Phosphate, (PO4-3), Iron, (Fe), total alkalinity, (CaCO3) total Chloride, (Cl-), Calcium hardness, total hardness, Magnesium hardness, Calcium (Ca),Magnesium (Mg),Sodium (Na) and Sulphate (SO4-2).The geological zones considered were the Benin Formation (BF), Ogwashi Asaba Formation (OAF), Nsukka Formation (NF), Alluvium Formation (AF), Imo Clay Shale Formation (ICSF), and False Bedded Sandstones Formation (FBSF). The average concentrations of total dissolved solids, chloride, nitrate, sulphate, total hardness and electric conductivity were higher in the dry season compared to the rainy season, while average concentrations potassium and bicarbonate were higher in wet season. The water quality index (WQI) was evaluated in accordance with WHO permissible standards for safe drinking water on a scale of 0 to 100. The WQI for dry season were 50.10, 24.98, 20.18, 35.79, 79.77 and 55.94 for BF, OAF, NF, AF, ICSF, and FBSF respectively while for rainy season, the WQI gotten were 35.04, 73.30, 27.54, 30.37, 86.98 and 108.95 for BF, OAF, NF, AF, ICSF and FBSF respectively. The results reveal that during dry season, groundwater samples from OAF and NF have excellent water quality, samples from BF, NF, and AF have good quality water and samples from ICSF have very poor water quality. The WQI obtained during the rainy season indicate that water samples from BF, NF and AF have good water quality  for drinking and agricultural applications based on national and international indices and standards while the water samples from OAF were of poor water quality. The water quality from ICSF is very poor and the water quality from FBSF unsuitable for drinking purpose. This suggests that there is need for continuous monitoring and treatment for acidic and high nitrate water to mitigate future pollution and ensure sustainable use of the groundwater resource.  XG Boost Model was used to model the dataset and a value of 142.829234 was obtained as the RMSE which subsequently decreased to 130.309532 at the final iteration.

Keywords:

XG Boost Model,  Physiochemical parameters, Water quality, Spatio-temporal variability, Hydrological formations