MA3 Aquatic Ecotoxicology
254 Portland Ballroom
8:00 AM - 12:00 PM, Monday
() An initial investigation of the potential impacts of pesticides on Golden Shiners in a Niagara region stream.
Park, B1, Struger, J 2, Parrott, J2, Evans, R1, Wautier, K1, Baron, C1, Kidd, K3, Gray, M4, 1 Department of Fisheries and Oceans, Winnipeg, Manitoba, Canada2 Environment Canada, Burlington, Ontario, Canada3 University of New Brunswick, St. John, New Brunswick, Canada4 University of Manitoba, Winnipeg, Manitoba, Canada
ABSTRACT- Twenty Mile Creek, Ontario, Canada. The creeks drainage basin supports intensive agricultural activity, including row cropping (eg. corn, soybean), vineyards and soft fruit production. Water samples were collected at 2 sites from April to October and screened for triazine, acetanilide and phenoxy acid herbicides and organophosphorouis insecticides. Triazine and phenoxy acid herbicides were frequently detected at the two downstream sites at concentrations ranging from 85 to 1600 ng/L. Golden shiners (Notemigonus crysoleucas) were collected as a sentinel species from four sites in April, June, July and September. Histological analyses revealed no apparent differences between sites in terms of gonad development, liver cell size or thyroid gland architecture. Muscle thyroid hormone content, measured as triiodothyronine (T3) was determined for fish collected in July. Mean T3 content was significantly lower in the furthest downstream site. Brain acetylcholinesterase (AChE) activity was 12-18% lower in the brain tissues of fish from the furthest downstream sites in April, but not in July samples. Fathead full life cycle exposure studies were conducted with water taken from the furthest downstream site, and indicate that reproductive timing was affected by exposure to this water. Research on the Twenty Mile Creek system is continuing in 2004.
Key words: golden shiners, pesticides, thyroid, cholinesterase