MONITORING OF METHOXYCHLOR RESIDUES IN THE ATHABASCA RIVER SYSTEM IN NORTHERN ALBERTA AFTER TREATMENT FOR CONTROL OF BLACK FLY LARVAL POPULATIONS

Methoxychlor (2,2-bis(p-methoxyphenyl)-1,1,1-trichloroethane) was used in the Athabasca River in northern Alberta for the control of black f ly larvae, Simulium arcticum, during May to July of 1981 to 1987. Samp les of river water and sediment were analyzed for methoxychlor residue s each year as part of Alberta Environment's program to assess environ mental impact and monitor compliance with issued permits. During 1985 fish samples were also collected at various sites downstream and upstr eam of the point of application of methoxychlor. This paper summarizes the residue data obtained by analysing these fish, sediment and water samples collected from the Athabasca River system during the years 19 81 to 1987.