HYDROGEOLOGICAL EVALUATION OF PARTS OF ISUOFIA AND ENVIRONS OF NANKA FORMATION IN ANAMBRA BASIN, SOUTH-EASTERN NIGERIA.

ABSTRACT

The study is aimed at determining the hydrogeological evaluation of parts of Isuofia and environs, South-Eastern Nigeria encompasses the evaluation of the physiochemical and microbial parameters in the surface and groundwater. The mapped area covers an extent of about 117.86  km² located in Anambra Basin. The study area is bounded by longitudes (7⁰ 0ʹ 0ʺ and 7⁰ 10ʹ 0ʺ) E and latitudes (5⁰ 55ʹ 0ʺ and 6⁰ 5ʹ 0ʺ) N. The area is underlain by Nanka Sands of the Ameki Group. The lithology consists of fine to coarse grained sands with abundant intercalations of calcareous shale and thin shaly limestone. Ten water samples were collected at random from the study areas. They include three river samples which include Location 3(Lake Atama), Location 8(River Otalu) and Location 10(River Obisi). Also seven groundwater sampleswere collected which include locations 1,2,4,5,6,7 and 9. Physico-chemical and microbial analysis were carried out to determine water quality. Results of the analysis showed high concentration of heavy metals, 0.381mg/l Fe, 0.099mg/l Cr, 0.017mg/l Cd, and 0.017mg/l Pb. Results also showed 3 10³ total heterotrophic bacterial count, 1 10³ total coliform count, and 0  10³ E.coli count. . Based on the result of water quality evaluation done in Isuofia and environs in comparison to the World Health Organization (WHO) standard for clean water quality, the water in the area is not potable. This could be as a result of infiltration of leachate, linkage from the septic tanks, coupled with runoff from dumpsites and poor environmental management of the area occasioned by anthropogenic activities.