Ecological and Human Health Implication of Heavy Metals in Soils of Urban Areas of Nigeria: A Systematic Review

Abstract

This paper involves a systematic review of the concentration, pollution, ecological, and health hazards connected with heavy metals in Nigerian urban soil. Data were sourced from published papers in peer reviewed journals after which they were subjected to contamination, ecological and health risk analysis. Arsenic in urban soils of Nigeria is between 0.003 mg/kg and 46.66 mg/kg while that of Cadmium is between 0.001 mg/kg and 239.20 mg/kg. The amount of Cobalt in urban soils of Nigeria is between 0.42 mg/kg and 24.43 mg/kg while that of Chromium is between 0.05 mg/kg and 1915.80 mg/kg. Cobalt in Nigerian urban soils of Nigeria is between 0.42 mg/kg and 24.43 mg/kg while that of Copper is between 0.54 mg/kg and 12,830 mg/kg. Mercury in urban soils of Nigeria is between 0.02 mg/kg and 46.258 mg/kg while that of Lead is between 0.36 mg/kg and 966.90 mg/kg and that of Zinc is between 0.31 mg/kg and 8420.60 mg/kg. Urban soils of Nigeria is lowly to very highly contaminated by the metals. Some sources of heavy metals in the soils include dumping of wastes, release of industrial waste water, exhausts from vehicular movement, petroleum spill, mining activities and cement production. Risk assessment showed that soils of major towns especially those in Abuja are pose very ecological risk. Children and adult are expose to carcinogenic health issues due to oral ingestion of soil contaminated by Pb while children are exposed to non-carcinogenic health risk through ingestion and dermal contact with polluted soils.