Health Risk Assessment of Sugarcane Grown in an Area under the Influence of Hospital Wastewater

Abstract

Plants like sugarcane grown in soils contaminated with metals inevitably take up some of the metals thereby posing a food safety issue. Sugarcane plant and soil were sampled from fifteen points in a sugarcane farm under direct influence of wastewater from KomfoAnokye Teaching Hospital (KATH), Kumasi, Ghana. The surface water passing through the sugarcane farm was sampled at five points within the farm. Samples collected and analysed using standard methods for lead (Pb), copper (Cu), cadmium (Cd), and manganese (Mn). Heavy metal concentrations in all water samples4.1 ± 0.11, 9.8±0.24, 0.4±0.12, 5.3±0.03 µg L^−1 for Pb, Cu, Cd, and Mn respectively. Significant difference (p = 0.0001) was obtained in metal concentrations analysed in the soil samples with metal concentrations ranged from 5.68 to 11.23 mg Kg^-1 for Pb, 25.43 to 25.69 mg Kg^-1 for Cu, 0.53 to 0.59 mg Kg^-1 for Cd and from 27.22 to 27.42 mg Kg^-1 for Mn. In this study, Pb, Cd, Cu, and Mn concentrations in sugarcane stem (edible portions) were 2.57,5.84,0.027, and 8.03 mg Kg^-1, respectively. These were all below their corresponding European Commission (EC) maximum tolerable limits for fresh foods. The metals analysed had a wide range of transfer factor (TF) values of 0.18 to 0.38, 0.1 to 0.35, 0.04-0.14, and 0.11-0.34 for Pb, Cu, Cd, and Mn respectively. The detected fraction in the edible parts (stem) of the sugar cane samples represented 50–90% of root concentrations. The trend in Pb, Cu, Cd, and Mn distribution in the soils stood the same with increasing distance from the stream (source of contamination). No significant difference existed between the levels at 0- 20m, 20-40m, and 40-60m (p=0.21). Metal pollution may have spread evenly within the area studied and long cultivation of sugarcane on the land could lead to high levels in the plant. The results suggest that sugarcane cultivated on soil impacted by the wastewater from KATH contain metals but not in levels above the recommended levels. However, since metal levels in plants do accumulate over time, routine monitoring is recommended.