Inter-annual trends of heavy metals in marine resources from the Nigerian territorial waters

Abstract

In an attempt to monitor and assess the pollution status of marine resources in the Nigerian territorial waters, this study was carried out to reveal the levels and inter-annual trend of heavy metals in marine resources from the Lagos lagoon marine ecosystem. Studies were carried out annually in the month of July between 2007 and 2009; and the observed levels and trends are herein reported and discussed. Drastic shoot up was observed in year 2009 at all locations in the levels of Fe, Zn, Cu, Cr, Pb, and Cd in surface water, with maximum values of 0.62, 1.14, 0.07, 0.06, 0.08, and 0.09 mg/L, respectively reported at the near shore locations. The maximum values recorded in year 2007 for Fe, Zn, Cu, Cr, Pb, and Cd in bottom sediments were 11533, 76.57, 16.23, 38.3, 41.29, and 0.94 mg/kg respectively. This study revealed a general inter-annual trends of 2009 > 2008 > 2007. This trend is alarming and it is of great concern considering the associated health and economic implications.

Key words: Gulf of Guinea, heavy metals, pollution, coastal water, seafood, human health, marine ecosystem.