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Concentrations of cadmium, cobalt, copper, chromium, iron, manganese, nickel, lead and zinc were determined in surface sediments of the Lagos Lagoon, Nigeria. The results revealed largely anthropogenic heavy metal enrichment and implicated urban and industrial wastes and runoff water transporting metals from land-derived wastes, as the sources of the enrichment. Higher levels (F < 0.05) of cadmium, iron, manganese, nickel and zinc occurred in sediment samples collected near industrialized-urban areas than in those from unindustrialized-rural areas only in the wet season. While iron constituted about 1% of dry sediment by weight, the other metals were present in trace amounts.

Tributaries of Lagos lagoon at Oworonsoki and Ebute Meta, known for residential and commercial activities were studied to assess the impact of coastal activities on Lagos lagoon. The mean levels of some parameters at the activity points gave evidences of pollution in the studied areas. The mean values for dissolved oxygen was 2.09 mg/l and chemical oxygen demand was 267 mg/l at Oworonsoki, while at Ebute meta, mean values for same parameters at the activity points were 1.16 mg/l and 786.5 mg/l respectively. The results obtained confirmed that the leachates generated from the activities at the studied locations contributed to the levels of some of the water quality parameters in Lagos lagoon.

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