On the 17th of October 2008, William Joseph Ntow from Ghana successfully defended his PhD thesis entitled ‘The use and fate of pesticides in vegetable-based agreoecosystems in Ghana.’
His promoter was Professor Huub Gijzen and Dr. Peter Kelderman was his co-promoter. The Promotion was jointly chaired by Wageningen University and UNESCO-IHE.
The use of a wide range of chemicals to destroy pests and weeds is an important aspect of agricultural practice in Ghana, contributing to increased crop yield and reduced post-harvest losses.
Notwithstanding the beneficial effects of pesticides, their adverse effects on environmental quality and human health constitute a major issue that gives rise to concerns at local, regional and national scales. The situation is particularly worrying in view of the lack of reliable data on the long-term consequences of exposure to pesticides.
Ntow’s thesis reports on current knowledge on pesticides use in vegetable farming in Ghana and establishes the fate of pesticides in situ in tropical vegetable-based agroecosystems, as well as their environmental and public health impacts on selected population groups.
Thus, water, waterbed sediment and vegetable crops (viz. tomato, cabbage, pepper, onion and eggplant) were checked for residues of the pesticides monitored on the farmers’ fields.
Data on persistent pesticide residues in farmers’ breast milk and blood serum indicated the presence of DDTs, dieldrin, HCB, and HCHs; this especially raises concerns for children’s health.
The thesis concludes that successful actions to reduce negative impacts of pesticides require sustained, low cost, and well-targeted training interventions.
Ntow’s research was carried out with financial support of the Dutch Government, the International Water Management Institute (IWMI), the International Foundation of Science (IFS) and the Organisation for the Prohibition of Chemical Weapons (OPCW).
Most of the Research was carried out at the Water Research Institute in Accra, Ghana, with technical assistance from the Kinneret Limnological Laboratory in Migdal, Israel.