Assessment of Heavy Metals, Water Quality and Health Risk of Surface Water in Some Towns and Villages Along Hawul River Basin

Abstract

For lives to be sustain adequate, safe and accessible water must be available for all 
and sundry. In fact, due to the importance of access to water, the United Nations 
made it a priority in sustainable development goal (SDGs 6) and history have it that 
access to water is a major factor in the settlements of most communities. Human 
activities have introduced so many chemical and biological contaminants in to the 
water bodies with devastating ecological and adverse health effect. Water quality 
index, Heavy metal pollution index, heavy metal evaluation index, environmental 
water quality index, Hazard quotient, Hazard index and incremental lifetime cancer 
risks were computed and the relevant findings presented as table and figures. The 
result of this study indicates poor water indices for all the sampling locations. HQoral 
values for heavy metals are less 1.0 which is the threshold for non-carcinogenic 
health hazard, thus, all the metals are within the acceptable limits of non
carcinogenic health risk hazard from all sampling sites. Hazard Index (HI) which is 
the summation of total potential non-carcinogenic health ranges between (5.8717 
X 10-5 - 2.0947 X 10-4) for dermal route with while (1.6643 x 10-5 - 3.3138 X 10-4) for 
oral route. Maximum Cancer risk contribution due to oral route are in order of As 
(5.3165 X 10-7) > Cr (3.1779 X 10-7) > Cd (2.2293 X 10-7) > Pb (6.1260 X 10-9), while 
that of dermal contribution are in the order Cr (9.5000 X 10-5) > Cd (2.0289 X 10-5) > 
As (2.4192 X 10-6) > Pb (8.813 X 10-9). The incremental cancer risk (ILCR) ranges 
between 2.9250 X 10-5 – 1.04 X 10-4 implying that about 29 to 104 out of a million 
people of the population in the study areas may suffer cancer in their lifetime as a 
result of the exposure from heavy metals.