WA8 Global Perspectives: Pesticide Risk Assessment in Developing Countries
A105 & A106
8:00 AM - 12:00 PM, Wednesday
() Unexpected risks from obsolete pesticide removal: reappearance of dieldrin in the environment.
Mullié, W.C.1, 2, Gadji, B.2, Sarr, M.2, Garba, H.3, Sow, O.4, 1 FAO, Locustox Project, BP 3300, Dakar, Senegal, Senegal2 Centre for Ecotoxicological Research in the Sahel, BP 3300, Dakar, Senegal, Senegal3 ENDA-PRONAT, BP 3370, Dakar, Senegal, Senegal4 Direction de l'Environnement et des Etablissements Classés, BP 6557, Dakar, Senegal, Senegal
ABSTRACT- In November 2003, 426.5 tons of obsolete pesticides, containing c. 56 ton of dieldrin, were shipped from Senegal to Germany for incineration. Dieldrin originated from government stores in St Louis and Richard Toll (both in the Senegal River Delta) and Dakar. A small quantity originated from a private company in Richard Toll. Between the latest inventory in 2001 and shipment, dieldrin started to disappear from its stores. This loss was calculated to be at least 21,000 liter, and probably more. Meanwhile, information was obtained that dieldrin had appeared illegally on the market for use as a termiticide in constructions. Between April 2003 and February 2004, 84 surface water samples from three villages in the Senegal River Delta (Pont Gendarme and Boundoum) and Senegal River Valley (Ouro Madio) were screened by GC for pesticide residues. Nineteen different pesticides were found above detection limits, of which dieldrin was the fourth most encountered molecule. Dieldrin was frequently found in Pont Gendarme and Ouro Madio, but never in Boundoum. Concentrations ranged from 0.1 to 3.0 
g l-1 (geometric mean 0.53 g l-1), which is up to 100 times the EU drinking water standard. Although no direct evidence exists that dieldrin residues originated from use of disappeared stocks, this may well have been the case. A recent study in peri-urban market gardens around Dakar in May-June 2002, only found very low levels of dieldrin in soil, vegetables and water, not exceeding drinking water standards. This shows that the situation in the Senegal Valley is markedly different and needs expanded monitoring. Illegal removal and recirculation of obsolete pesticides may jeopardize the Africa Stockpiles Programme, a collaborative effort of FAO, World Bank, Industry and NGOs for obsolete pesticide removal and clean-up, as the Senegalese case shows. Therefore great care is needed to prevent persistent pesticides from reviving a second life.
Key words: senegal, dieldrin residues, obsolete pesticides, surface water