Pollution and risk assessment of phenolic compounds in drinking water sources from South-Western Nigeria
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Date
2023
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Springer
Abstract
This study reports the occurrence and risk assessment of 2,4-dinitrophenol (2,4-DNP), phenol (PHE), and 2,4,6-trichlorophenol
(2,4,6-TCP) in drinking water sources in three south-western States in Nigeria (Osun, Oyo, and Lagos). Groundwater (GW) and
surface water (SW) were collected during dry and rainy seasons of a year. The detection frequency of the phenolic compounds
followed the trend Phenol > 2,4-DNP > 2,4,6-TCP. The mean concentrations of 2,4-DNP, Phenol, and 2,4,6-TCP in GW/SW
samples from Osun State were 639/553 μg L−1, 261/262 μg L−1, and 169/131 μg L−1 during the rainy season and 154/7 μg
L−1, 78/37 μg L−1, and 123/15 μg L−1 during the dry season, respectively. In Oyo State, the mean concentrations were 165/391
μg L−1 for 2,4-DNP and 71/231 μg L−1 for Phenol in GW/SW samples, respectively, during the rainy season. Generally, in the
dry season, these values decreased. In any case, these concentrations are higher than those previously reported in water from
other countries. The concentration of 2,4-DNP in water posed serious ecological risks to Daphnia on the acute scale while it
was algae on the chronic scale. Estimated daily intake and hazard quotient calculations suggest that 2,4-DNP and 2,4,6-TCP
in water pose serious toxicity concerns to humans. Additionally, the concentration of 2,4,6-TCP in water from Osun State in
both seasons of the year and in both groundwater and surface water poses significant carcinogenic risks to persons ingesting
water from these sources in the State. Every exposure group studied were at risk from ingesting these phenolic compounds in
water. However, this risk decreased with increasing age of the exposure group. Results from the principal component analysis
indicate that 2,4-DNP in water samples is from an anthropogenic source different from that for Phenol and 2,4,6-TCP. There is
a strong need to treat water from GW and SW systems in these States before ingesting while assessing their quality regularly.