Urbanizing with or without nature: pollution effects of human activities on water quality of major rivers that drain the Kumasi Metropolis of Ghana.

The effects of urbanization such as population upsurge, increased industrialization, urban agriculture, and rural-urban migration of persons exert pressure on the limited water resources in most cities. This study investigated the impact of human activities on the water and sediment quality of the three main rivers (Wiwi, Subin, and Suntre) in Kumasi, the second-largest city in Ghana. The physicochemical parameters and the concentrations of contaminants, including heavy metals, polycyclic aromatic hydrocarbons, pesticide residues, and microbial loads in the rivers, were linked to the specific human activities at the riverbanks. While all the 37 pesticide residues investigated in river sediments had concentrations below the detection limits (0.005 mg/kg for organochlorines, 0.010 mg/kg for organophosphates, and 0.010 mg/kg for synthetic pyrethroids), the study showed that the sediments are polluted with petrogenic and pyrogenic polycyclic aromatic hydrocarbons. River Subin, the most polluted among the three rivers, recorded benzo[e]pyrene concentrations up to 47,169 µg/kg. The geoaccumulation index and concentration factors show that the rivers are highly contaminated with metals such as cadmium, chromium, mercury, and arsenic and are related to human activities. The microbial quality of the rivers was poor, recording specific microbial loads of 6.8, 4.1, and 1.5 × 107 counts/100 mL respectively for Wiwi, Subin, and the Suntre Rivers. The three water bodies are therefore not suitable for recreational and irrigational purposes.

Human health risk assessment of potentially toxic elements in soil and air particulate matter of automobile hub environments in Kumasi, Ghana.

Rapid urbanization and uncontrolled industrial activities in developing countries have raised concerns about potentially toxic metal contamination of the environment. This study assessed the levels of potentially toxic elements in soil and airborne particulate matter in the Suame and Asafo areas in the Kumasi metropolis, characterized by a high concentration of auto mechanic workshops and residential settlements. X-ray fluorescence analysis and inductively coupled plasma-mass spectrometry were used to determine the metal concentrations in the samples. The results showed high concentrations of potentially toxic elements in the soil and air samples, indicating contamination from automotive activities. Metals such as Co, Ni, Pb, and Zn were found to be present at concentrations (13.42-6101.58 mg/kg and 14.15-11.74 mg/kg for Suame and Asafo respectively) that pose potential health risks to exposed populations. Mathematical models such as pollution indices were used to assess the extent of contamination and determine the potential sources of the metals - the automotive repairs. The findings highlight the urgent need for environmental management and remediation strategies to mitigate the health risks of exposure to potentially toxic elements in the Kumasi metropolis automotive hub.