Ahmadu Bello University (ABU) drinking water treatment plant (ABUDWTP) uses calcium hypochlorite to
supply chlorine in disinfecting drinking water supply to the university community. Between 2008 and 2010, 252
water samples were taken in duplicates along the treatment and distribution systems of ABUDWTP with
ammonium chloride as de-chlorinating agent in accordance with United States Environmental Protection Agency
(USEPA) Method 551.1. This was aimed at determining the concentrations of trihalomethanes (THMs)
disinfection by-products (THM-DBPs) and the degree of wholesomeness of the drinking water supplied. The
THM concentrations in the samples were analysed using Agilent Gas Chromatograph after preliminary
extraction with methyl tert-butyl ether (MTBE). Samples’ analyses identified six THMs - two additional to the
regulated four. These are Dichlorobromomethane and 1,2-Dibromomethane here classified as emerging THM
disinfection by-products (EmerTHM-DBPs). Measured total mean concentration of the regulated THMs
(TRegTHM-DBPs) at house level was 1.0601E-02±1.6625E-05 mg/L as against 9.9704E-02±6.4706E-05 mg/L
for total mean emerging THM-DBPs (TEmergTHM-DBPs). This TRegTHMs concentration indicates house
level water is within acceptable limits of international standards despite being above the national permissible
limit of 0.001 mg/L. Though not considered under exiting drinking water quality index TEmergTHM-DBPs
were found to account for over 90% of gross THM-DBPs (GTTHM-DBPs) at each sampling stage. These
TEmergTHM-DBPs could create health complications on consumers as they are either suspected carcinogens or
recognised to increase the risk of carcinogenicity and mutagenicity in humans. Both are irritants of several body
tissues and are implicated in several health abnormalities including reproductive and fertility disorders as well as
liver and kidney damage. In view of these likely supplementary health burdens, this paper advocates additional
stricter monitoring and control of these emerging THM-DBPs as they will most probably compound and increase
the frontline of health challenges from chlorine disinfected ABU drinking water supply to its consumer
