The urban informal sector's activities and its influence on soil and water quality of some Southern Nigerian Cities

Abstract

The magnitude of informal sector events and activities may pose serious environmental consequences which may affect soil and water quality. This study investigated the effects of informal sector activities on the physicochemical, microbiological properties, and total metal levels of soil and water in Port Harcourt and Owerri, Southern Nigeria. Composite soil and water samples were taken from sites where informal sector activities are carried out in each study location. The samples were analyzed to establish their physicochemical and microbial quality by standard methods. The data obtained were subjected to further treatments using some environmental models to establish the degree of contamination and overall quality. Results showed pH levels were normal (within 6–8). The electrical conductivity, cation exchange capacity, exchangeable acidity, and organic matter in the soils were higher than in the control samples. The trend for metals in the soils was Fe > Cr > Cd > Pb > As, with Cd and Pb showing high contamination. The microbial counts in soil samples were higher than the control soils except for TFC in Owerri (3.5 × 104 cfu/g). Water samples showed low contamination with most physicochemical properties within the permissible limits. However, the water quality index of some samples (33% in Port Harcourt and 100% in Owerri) indicates unsuitability of the water for consumption. Microbial load in water was very high in all samples in Owerri while only 17% showed significant contamination in Port Harcourt. The principal component analysis suggested that both geogenic and anthropogenic factors contributed to the accumulation of metals determined in the investigated soils and water samples. The study was able to expose the consequences of activities of this sector on the quality of soil and water as well as the associated risks. Hence, it is recommended that activities of the informal sector should be regulated to forestall environmental degradation.