PARENT SESSION
PS21 - POPs: Organisms & Atmospheric Transport
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P199) Ambient Air Concentrations of Persistent Organochlorine Pesticides in the Northern Lake Victoria Watershed.

Wejuli, Michael^*,1, Muir, Derek², Hecky, Robert³, Magunda, Matthias¹, Teixeira, Camilla², Fellin, Phil⁴, ¹ Kawanda Agricultural Research Institute, Kampala, Uganda² Environment Canada, NWRI, Burlington, ON, Canada³ Dept of Biology, University of Waterloo, Waterloo, ON, Canada⁴ AirZone Inc, Mississauga, ON

ABSTRACT- Organochlorine pesticides are still in use in the East African region for agricultural purposes and for the control of mosquitoes. Ambient air concentrations of these compounds are expected to be higher in the tropics compared to temperate regions due to prevailing high temperatures. However, no study has been conducted to investigate atmospheric transport and deposition of pesticides in this region. In this study ambient air concentration of organochlorine pesticides were determined at Kakira, Jinja (Uganda). The levels in pg/m³ of DDT (total) ranged from 64.8-610.9 (aver. 155.5), p,p'-DDT 19.2-390.1 (aver. 60.0), o,p'-DDT 11.2-62.8 (aver. 21.1), dieldrin 23.6-90.8 (aver. 45.7), -endosulfan 32.5-206.1 (aver. 92.4), lindane (-HCH) 20.3-183.6 (aver. 70.5), while chlordane and heptachlor ranged from <0.1-4.6 (aver. 2.7, 0.4 respectively). The persistent p,p'-DDT metabolite, p,p'-DDE was also relatively high ranging from 29.9-109.9 pg/m³. The most frequently detected pesticides were -endosulfan and -HCH. However, p,p'-DDT had the highest value of 390 pg/m³. Average levels of p,p'-DDT and p,p'-DDE at Kakira were lower than those reported for Brazzaville (Congo) but higher than those reported for Lake Baikal and Southern Ontario while -HCH, -HCH, total chlordane, and hexachlorobenzene (HCB) concentrations for Kakira were lower than those reported for Brazaville, Lake Baikal, Southern Ontaria, Arctic and Antarctic. In comparison with data from Senga Bay, Lake Malawi in Malawi, average DDT (total), p,p'-DDE, p,p'-DDT, o,p'-DDT, -HCH and total HCH levels were higher whereas average dieldrin, -HCH, chlordane and HCB levels were lower.

Key words: organochlorines, pesticides, air, tropics