EFFECTS OF SOLID WASTE DISPOSAL ON THE GROUNDWATER RESOURCES OF LOKOJA METROPOLIS, KOGI STATE, NORTH CENTRAL, NIGERIA

Abstract

 Assessment of Groundwater quality is very vital for a sustainable groundwater resources management. The quality of groundwater all over the world is deteriorating at a fast rate due to industrialization, urbanization, indiscriminate disposal of refuse and sewages. Assessment of the effect of solid waste disposal on the groundwater resources of Lokoja metropolis was undertaken with emphasis on the hydrochemical quality of the shallow groundwater system. The study approach involved field sampling and in situ measurements of physico-chemical parameters followed by hydrochemical analyses of the water samples. In situ measurements revealed Electrical Conductivity (EC) value ranges from 214.00 to 1703.00 µS/cm (av 734.93 µS/cm) and The pH value ranges from 6.00 to 8.80 (av 7.70). Results of the analysis shows that the cationic and anionic concentration varies as follows: Mg2+ ranges from 22.00 to 775.50 mg/l, (av 314.70 mg/l). Ca2+ ranges from 1.50 to 106.00 mg/l, (av 33.20 mg/l) K+ ranges from 9.40 to 134.00 mg/l, (av 23.83 mg/l). Na+ranges from 18.60 to 4789.00 mg/l, (av 0.65 mg/l). Fe ranges

from 0.02 to 5.70 mg/l, (av 0.04 mg/l). HCO3- ranges from 126.00 – 3111.00 mg/l, (av 720.20 mg/l). Cl-

2- ranges from 5.0 to 2625.00 mg/l, (av 63.36 mg/l). SO4 ranges from 12.50 to 16.90 mg/ l, (av 19.06 mg/l). The study also reveals that the groundwater in areas where solid wastes are being dump, in most cases, is slightly alkaline (pH ranging from 6.01 to 8.77), slightly saline (TDS ranging from 98.60 to 816.00 mg/l), and belongs to seven hydrochemical facies, namely: Ca-Mg-Cl-HCO3, Ca-Mg-HCO3,

Mg-Ca, Mg-Ca-Cl-HCO3, Mg-Ca-HCO3, Mg-Ca-HCO3-Cl and Mg-HCO3. The dominant

hydrochemical facies are Mg–HCO3 and Mg-Ca-HCO3 while Ca–Mg–Cl- HCO3, Ca-Mg-HCO3, Mg –

Ca and Mg-Ca-Cl-HCO3 constitute the minor water type. Statistical correlation reveals positive correlation between most of the parameters. With the exception of Na, Fe, Zn, and Cl, all other parameters are mostly above the World Health Organisation (2011) standards for drinking water. Conclusively, the overall hydrochemical facies with TDS values of over 500.00 mg/l in most of the sampled areas reveals that the groundwater is slightly polluted and may be considered not suitable for drinking but very suitable for irrigation purpose due to its low Sodium hazard and low salinity.