PARENT SESSION
PWA17 - Agrochemicals
8:00 AM to 6:30 PM - Wednesday, November 14, 2001
Exhibit Hall A

(PW217) In-use Pesticide Concentrations in Surface Waters of the Canadian Great Lakes, 1994-1999.

Struger, John ¹, L'Italien, Serge¹, ¹

ABSTRACT- Pesticides are heavily used in agricultural production in the Great Lakes basin. Large volume surface water samples were collected between 1994 and 1999 from various Great Lakes locations including Lakes Ontario, Erie, Huron, and Superior. Samples were analyzed for triazine, neutral and phenoxy acid herbicides and organophosphorus and insecticides. Nineteen different in-use pesticides were detected including: seven phenoxy acid herbicides, three neutral herbicides, and nine organophosphorus insecticides. The maximum concentrations measured in surface waters in the study were 1039 ng/L for atrazine and 736 ng/L for metolachlor. Maximum concentrations were observed in the lower Great Lakes especially in the western basin of Lake Erie. Spatial and seasonal patterns of pesticide distribution were observed and linked to sources and inputs. These data will be discussed in relation to aquatic life guidelines, pesticide use information, and possible implications to Great Lakes aquatic ecosystems.

Key words: Agricultural pesticides, Great Lakes