Title: Salinity intrusion and groundwater quality in a coastal megacity - Lagos, Nigeria

Authors: Funmi O. Jaja; Mynepalli K.C. Sridhar; Elizabeth O. Oloruntoba; Mumuni Adejumo

Addresses: Faculty of Public Health, Department of Environmental Health Sciences, College of Medicine, University of Ibadan, Ibadan, Nigeria ' Faculty of Public Health, Department of Environmental Health Sciences, College of Medicine, University of Ibadan, Ibadan, Nigeria ' Faculty of Public Health, Department of Environmental Health Sciences, College of Medicine, University of Ibadan, Ibadan, Nigeria ' Faculty of Public Health, Department of Environmental Health Sciences, College of Medicine, University of Ibadan, Ibadan, Nigeria

Abstract: This study assessed the seasonal variation in the groundwater quality and extent of saline intrusion in a Nigerian coastal megacity, Lagos. Sampling points were grouped into four zones: Lagoon water, and ground waters from zone 1 (< 5 km from Lagoon), zone 2 (5-10 km from Lagoon) and zone 3 (10 km and above from Lagoon), respectively. Water samples (rainy and dry season) were collected from all the sampling points and analysed for electrical conductivity, salinity, total hardness and other selected physico-chemical parameters. Electrical conductivity and salinity values in samples from all the sampling points over the two seasons were within the World Health Organization (WHO) and Standards Organisation of Nigeria (SON) recommended limits. The total hardness values determined in the two seasons (rainy vs. dry) for zone 1, zone 2 and zone 3 were (443.3 ± 14.9 vs. 566.7 ± 22.9) mg L⁻¹, (96.3 ± 23.6 vs. 110.0 ± 28.3) mg L⁻¹ and (53.0 ± 10.5 vs. 63.3 ± 14.7) mg L⁻¹ respectively. The water was hard in zone 1 over the two seasons but other parameters in zones 1, 2 and 3 met the recommended limits for potable water.

Keywords: groundwater quality; saline intrusion; salinity; chloride; total hardness; coastal megacities; Lagos; Nigeria; seasonal variation; electrical conductivity; potable water; drinking water; water quality; cities.

DOI: 10.1504/IJW.2016.079699

International Journal of Water, 2016 Vol.10 No.4, pp.315 - 327

Received: 24 Oct 2013
Accepted: 02 Sep 2014
Published online: 10 Oct 2016 *

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