The Densu River Basin constitutes one of the largest agricultural areas in Ghana. The practice of using pesticides such as organochlorines, organophosphates, carbamates, pyrethroids and several others in agriculture and public health programs has raised concerns about potentially adverse effects on human health and the environment. In this study, a field survey was conducted to assess farmers' knowledge of safe handling and use of pesticides. Residues of pesticides in fish samples as well as the potential health risk associated with exposure to these pesticides were also evaluated. Data obtained from the field survey indicate that a very high proportion of farmers are at high risk of pesticide poisoning from occupational exposure. More than 90% of farm workers do not practice safety precaution during pesticide formulation and application leading to considerable prevalence of pesticide related illness in this agricultural community. Pesticide residues in fish samples varied greatly; from 0.10 µg•Kg-1 to 30.90 µg•Kg-1 , consumption of fish and fisheries product from the basin was no zero risk. The estimated dose for aldrin, methoxychlor, γ-chlordane, endrin aldehyde, endrin ketone, endrin, p'p'-DDT and δ-HCH do not pose a direct hazard to human health, although present in fish samples since the values were lower than toxic thresholds as well as reference dose. However, γ-HCH, heptachlor, α-endosulfan, endosulfan Sulphate, p'p'-DDE and dieldrin levels exceeded the reference dose, indicating a great potential for systemic toxicity in children who are considered to be the most vulnerable population subgroup.

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Radiation is part of the natural environment: it is estimated that approximately 80 % of all human exposure comes from naturally occurring or background radiation. Certain extractive industries such as mining and oil logging have the potential to increase the risk of radiation exposure to the environment and humans by concentrating the quantities of naturally occurring radiation beyond normal background levels (Azeri-Chirag-Gunashli 2004).

Rainfall erosivity is the potential ability for rainfall to cause soil loss. The purpose of this study was to estimate the rainfall erosivity index for the Ghana Atomic Energy Commission site in order to compute the surface erosion rate. Monthly rainfall data, for the period 2003–2012 were used to compute annual rainfall erosivity indices for the site, using the Modified Fournier index. Values of the annual rainfall erosivity indices ranged from 73.5 mm for 2004 to 200.4 mm for the year 2003 with a mean annual erosivity index of 129.8 mm for the period. The Pearson’s Coefficient of Correlation was used to establish the relationship between annual rainfall and annual rainfall erosivity. This showed a high degree of positive relationship (r = 0.7) for the study area. The computed mean annual erosivity index revealed that the site is in the high erosion risk zone. Therefore, it is necessary to develop soil protection and management strategies to protect the soil from erosion.

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