HYDROCHEMISTRY AND HEAVY METAL DISTRIBUTION IN SURFACE WATERS AND SEDIMENTS FROM THE LAGOS LAGOON COMPLEX

Abstract

ABSTRACT
Industrial wastes constitute a major source of heavy metal contamination in coastal waters. This study was carried
out to assess the hydrochemistry and heavy metal distribution in surface water and sediments from selected sites
in the Lagos lagoon complex. Water and sediment samples were collected monthly between June and November
2021 from five sampling stations, and analysed in the laboratory following standard methods. The result showed
that heavy metal concentration in water was lower than WHO standards. The metals, arsenic, iron, and nickel
exhibited significant (P<0.05) spatial variation in sediments. The highest and lowest concentrations of arsenic and
nickel in sediments were observed at Badagry and Langbasa respectively; while Fe was highest in Langbasa and
lowest in Badagry. The highest and lowest values for all physicochemical water parameters were recorded at
Bayeku and Badagry respectively, except turbidity and carbon dioxide. Conductivity, total dissolved solids,
turbidity and total hardness at Bayeku and Langbasa exceeded WHO standard. The findings from this study
emphasise the need for regular monitoring of the Lagos Lagoon Complex