Persistent Organochlorine Compounds in the Water and Sediment Samples from the Lake Bosomtwe in Ghana

Aims: To investigate the burden of organochlorine pesticides (OCPs) and its degradation products as well as indicator polychlorinated biphenyl (PCBs) in the water and sediments.

Study Design: This investigation involved one year monitoring of the Lake.

Place and Duration of Study: Lake Bosomtwi was the study area and analysis of samples was carried out at the Nuclear Chemistry and Environmental Research Centre of Ghana Atomic Energy Commission from January 2012 to February 2013. Samples were collected three times during dry, wet and minor wet seasons.

Methodology: Liquid-liquid extraction with hexane was used for the water samples while sediment samples were sonicated on ultrasonic bath with hexane/acetone mixture (3:1). The extracts were then cleaned up with florisil and quantified on a micro-capillary gas chromatography equipped with electron capture detector.

Results: Eight OCPs and four indicator PCBs were detected in water while sixteen OCPs and five indicator PCBs were also detected in the sediments. The highest OCPs concentration in water was 6.35 µg/l while that for the sediments was found to be 15.23 µg/kg. The total PCBs load (sum of all indicator PCBs) ranged from 1.09 – 7.19 µg/l and 6.43 – 19.17 µg/kg for the water and sediments respectively.

Conclusion: The study has shown that organochlorine compounds are present in the Lake Bosomtwi. The detection of organochlorine pesticides in water and sediments could be attributed either to historical use of these chemicals for agricultural purpose or environmental transport of these chemicals to the study area. The presence of indicator polychlorinated biphenyls could on the other hand be attributed to release to the environment during anthropogenic processes such as incineration, combustion and smelting. Leakages from refuse dumps containing dumped transformers and capacitors could also be a contributor to PCBs presence in the Lake.