Heavy metal levels in soil samples from highly industrialized Lagos environment

Abstract

The effect of heavy metals on the environment is of serious concern and threatens life in all forms. Environmental contamination is correlated with the degree of industrialization and intensities of chemical usage. The aim of this study was to determine to what extent, human and industrial activities have affected the quality of soil due to contamination of soil with heavy metals and the consequent effects on the health status of the inhabitants. Twenty five sites representing 25 soil samples were collected from various manufacturing companies which include: Mattress manufacturing companies, artificial hair manufacturing companies, farm lands, soft drinks bottling companies, electrical/ electronics companies and pharmaceutical companies. Soil samples from these sites were air-dried and digested with nitric acid. Digested samples were analyzed using Atomic Absorptive Spectophotometry (AAS) with a lamp current set at 5-8 mA, reslope limits of 75-125%. The levels of cadmium, arsenic, lead, chromium, iron and copper in mg/kg ranged from 0.56-4.2, ND, 2.10-12.50, 0.24-2.20, 1111-2216 and 2.20- 5.58 in all of the samples, respectively. These results show that the soil samples from dump yards, mattress manufacturing companies and soft drinks bottling companies had the highest concentration of heavy metals in them. Cadmium and iron levels exceeded that of the European Regulatory Standards (ERS).

Key words: Heavy metals, environment, contamination, industrialization.