TITLE:
In Search of Portable Water Supplies within a Brine and Mine Water-Invaded Region for Serving Some Communities around Ishiagu, Afikpo and Environs in Abakaliki Basin, Southeast Nigeria
AUTHORS:
Charles Chibueze Ugbor
KEYWORDS:
Abakaliki Basin, Portable Water, Brine Aquifer, Salt Lake, Pollution, Desaline Water
JOURNAL NAME:
International Journal of Geosciences,
Vol.14 No.2,
February
13,
2023
ABSTRACT: The study investigates the hydrogeochemical characteristics of some towns in
the Abakaliki Basin, comprising, Ishiagu, Aka Eze, Amaseri, Afikpo and Okposi communities, with the aim of sourcing for
portable water in the area. The basin
is underlain by Albian sediments, essentially shales, in the lowlands,
which were affected by low-grade
metamorphism that had produced slates. The highlands comprise basic intrusives
from episodes of magmatism and metallic ore
mineralisation. Injection of brines into the aquifer system and low,
seasonal aquifer recharge from rainfall results in poor water quality in the area. The study analyzes the geochemical distribution in water sources in the area and identifies sources of pollutants to guide the better choice of portable water. Results of hydrogeochemical
analysis of both surface and groundwater from the communities were
compared with World Health Organization to identify portable water locations in
the area. While the salt lake at Okposi is the main source of brine intrusion
in the study area, the Pb/Zn mine at Ishiagu is the main source of mine-water
pollution in the study area. Most chemical
parameters, (especially Cl-, Na+, Ca2+, Mg2+, SO42-, HCO3-) maintain high
concentrations within the salt lake area, with the values declining away from the salt lake. The main anthropogenic
source of pollution in the area, especially at Ishiagu, is the
indiscriminate surface mining of lead-zinc without proposer waste management
practices. Possible sourcing for portable
water in the study area includes a deep borehole at Ishiagu, away
from lead-zinc intrusives. At the Okposi axis, searching for portable water in boreholes should target shallower aquifers that do not communicate with the deeper-seated brine zones, likewise targeting zones
farther away from these brine-invaded areas. A controlled pumping rate
could potentially ensure that the cone of
depression was not low enough to reach the brine zone at depth. In
addition, desalination could also potentially render the salt water drinkable
if properly handled to eliminate the high concentration of salts in the water
to the level of acceptable limit by the WHO. Based on the study, the best area
to target for portable water in the study area is Afikpo, with most geochemical elements naturally occurring within WHO’s
standard concentration while portable
water could be harnessed in areas further away from mining sites, especially
at deep groundwater.