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

(STR-1117-829987) Occurrence of current-use pesticides in surface waters of Ontario, Canada.

Struger, J.¹, Sverko, E.¹, Marvin, C.¹, Dove, A.¹, Backus, S.¹, Muir, D.¹, Martin, P.¹, Hewitt, M.¹, Thompson, D.², Palace, V.³, ¹ Environment Canada, Burlington, ON, Canada² Natural Resources Canada, Sault Ste. Marie, ON, Canada³ DFO, Winnipeg, MA, Canada

ABSTRACT- There are limited data on the occurrence, distribution and fate of current-use pesticides in surface waters of watersheds in Ontario. As part of the Environment Canada National Project on Water Quality Surveillance (Pesticide Science Fund) samples were collected over a three year period starting in 2003. Surface water samples were collected from approximately 30 sites located in the Great Lakes Basin including small agricultural and urban watersheds distributed throughout Ontario. The survey design incorporated spatial and seasonal components to determine the distribution and fate of current-use pesticides in relation to use and application. Surface water samples were collected monthly or bi-monthly from April-November and were analyzed for a suite of pesticides including neutral herbicides (e.g. atrazine and metolachlor), phenoxy acid herbicides (e.g. 2,4-D, dicamba and mecoprop) and organophosphorous insecticides (e.g. diazinon and chlorpyrifos). Additional pesticides analyzed included pyrethroid insecticides, glyphosate, imidacloprid, methoprene and metabolites and sulfonyl urea herbicides. Maximum concentrations in surface waters of commonly detected pesticides included atrazine (1590 ng/L), desethyl atrazine ( 472 ng/L), metolachlor (1560 ng/L), 2,4-D (6940 ng/L), mecoprop (6580 ng/L) and dicamba (7100 ng/L). Several orgnophosphorous insecticides were occasionally detected including diazinon (maximum 5490 ng/L), azinphos methyl (6140 ng/L), chlorpyrifos (205 ng/L) and dimethoate (175 ng/L). Glyphosate was also detected occasionally in water. The applicability of immunoassay screening techniques was also evaluated for atrazine, metolachlor and diazinon. Pesticide concentrations were assessed against applicable water quality criteria. In addition, the effects of pesticides on biological responses of wild fish populations (golden shiner) and amphibian populations (leopard and green frogs) in selected drainage systems were measured.

Key words: pesticides, surface waters, agricultural, urban