MP5 Agrochemicals and Pesticides
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(STR-1117-657527) Methoprene and metabolite levels in urban stormwater catch basins and streams in southern Ontario.

Struger, J.¹, Sverko, E.¹, Grabuski, J.¹, Gilmer, E.¹, Marvin, C.¹, Fletcher, T.², ¹ Environment Canada, Burlington, ON, Canada² Ontario Ministry of the Environment, Toronto, ON, Canada

ABSTRACT- In recent years West Nile Virus has become a major health concern in eastern North America. In response to these health concerns in 2003, municipalities in southern Ontario initiated a mosquito control program using the insecticide methoprene. In 2003 methoprene was applied in pellet form to stormwater catch basins periodically (1-3 times) during May to August. During the application period, surface water sampling was carried out at several catch basins and urban streams located downstream of stormwater inputs in the cities of Hamilton, Burlington and Ottawa. Water samples were collected in catch basins and streams during dry and wet events. Methoprene determinations were conducted by using solid phase extraction cartridges analyzed by GC-MS. Methoprene was detected twice in streams and only during wet (storm)events. It was frequently detected in catch basins during dry and wet events. The maximum concentration measured in the streams was 0.65 ug/L and 4.35 ug/L in the catch basins. In 2004, targetted studies were conducted during precipitation events which also included methoprene metabolite analyses. The metabolites analyzed included: methoprenic acid, citronellic acid, methoprene epoxide and citronellal. These data will be discussed in relation to analytical issues and toxicity information.

Key words: methoprene, metabolites, surface waters, West Nile Virus