Thesis Abstract

Abstract
The mechanic village in Uyo metropolis, Nigeria, serves as a hub for various mechanical and automobile repair activities, potentially leading to the accumulation of trace metals in the surrounding soils. This study aimed to investigate the physicochemical properties and assess the levels of trace metals in soils at the mechanic village in Uyo. Soil samples were collected from different locations within the mechanic village and analyzed for pH, organic matter content, particle size distribution, and concentrations of trace metals including lead, cadmium, chromium, and nickel. The results indicated that the soils in the mechanic village were slightly acidic to neutral with pH values ranging from 6.1 to 7.2. The organic matter content varied from 1.2% to 2.5%, indicating moderate organic enrichment. Particle size analysis revealed that the soils were predominantly sandy loam in texture. The concentrations of trace metals in the soils varied, with lead levels ranging from 12.5 to 45.7 mg/kg, cadmium levels from 0.8 to 2.3 mg/kg, chromium levels from 14.6 to 28.9 mg/kg, and nickel levels from 8.3 to 15.7 mg/kg. These trace metal levels were higher than the background concentrations reported for uncontaminated soils, indicating potential contamination in the mechanic village soils. The enrichment factors for the trace metals suggested that lead, cadmium, and chromium were significantly enriched in the soils, possibly due to anthropogenic activities associated with mechanical repairs. The assessment of trace metal levels in the soils at the mechanic village is crucial for understanding the extent of contamination and potential risks to human health and the environment. Effective soil management practices and remediation strategies should be implemented to mitigate the impacts of trace metal contamination in the mechanic village soils and safeguard human health and environmental quality. Further studies on the sources and pathways of trace metal contamination in the mechanic village soils are recommended to develop sustainable solutions for soil quality improvement and pollution prevention in similar settings.

Thesis Overview

Trace metals are chemical elements found in all kinds of soils and arePredominant in soils with density greater than 5g/dm3 (Freedman, 1996). The very low general level of their content in soils and plants as well as the biological role of most of them makes them microelements. (Lacatusu, 1998). Assessment of trace metal levels in soils around various industries have been a major concern over the years, due to increased industrial activities as well as poor waste management. The levels of lead, copper, cadmium, nickel, and so on have been chosen as representative metals for which their concentration in the environment may be used as a reliable index of environmental pollution.

              Among the various toxic substances released through industrial activities, trace metals have been seen as a key marker because they can be analysed effectively and consistently in most environmental matrices. These inorganic pollutants are not degradable by natural processes unlike their organic counterpart, which degrade to less harmful components as a result of biological or chemical processes. Hence the efforts of trace metal pollution on local environments in close proximity to these industrial areas may therefore be substantial and long lasting inspite of extensive remediation efforts. (Amiard, Meyer 1995).

In addition, increased automobile repair activities in Nigeria as a result of excessive inflow of used tokunbo vehicles into the country has contribute significantly to the problem of soil contamination in most cities. The waste oil used for cleaning machine parts during servicing, the grease used for lubrication, metal scraps as well as used batteries are indiscriminately discarded on soils by automobile Engineers. The metals from these sources gets into the soil matrix and are taken up by plants in amounts that has detrimental effects on people or animals that consumes these plants. The problem of trace metal pollution is not restricted to Nigeria alone, in most parts of the world, large amount of trace metal have been directly discharged to nearby lands as well as surface water where food crops are grown and animals are reared, and human beings feed on these things. This activity adversely affects the quality of air, soil and ground water, in such a way that it becomes a subject of serious concern worldwide.