Refined aquatic risk assessment for aldicarb in the United States.
Aldicarb is a systemic insecticide applied directly to soil and to control mites, nematodes, and aphids on a variety of crops (e.g., cotton, potatoes, peanuts). It is highly soluble in water (6,000 mg/L) and mobile in soils (K(oc) = 100). As a result, aldicarb has the potential to be transported to aquatic systems close to treated fields. The US Environmental Protection Agency (USEPA) recently conducted an aquatic screening-level ERA for aldicarb as part of the re-registration review process. We conducted a refined risk assessment for aldicarb to characterize better the risks posed by aldicarb to fish and invertebrates inhabiting small freshwater ponds near agricultural areas. For the exposure assessment, tier II PRZM/EXAMS (Predicted Root Zone Model [PRZM] and Exposure Analysis Modelling System [EXAMS]) modelling was conducted to estimate 30-y distributions of peak concentrations of aldicarb and the carbamate metabolites (aldicarb sulfoxide, aldicarb sulfone) in surface waters of a standard pond arising from different uses of aldicarb. The effects assessment was performed using a species sensitivity distribution (SSD) approach. The resulting risk curves as well as available incident reports suggest that risks to freshwater fish and invertebrates from exposure to aldicarb are minor. The available monitoring data did not provide conclusive evidence about risks to aquatic biota.
Moore
Dwayne R J
DR
Intrinsik Environmental Sciences, Inc., 1550A Laperriere Ave., Suite 103, Ottawa, Ontario K1Z 7T2, Canada. dmoore@intrinsikscience.com
Thompson
Ryan P
RP
Rodney
Sara I
SI
Fischer
David
D
Ramanarayanan
Tharacad
T
Hall
Tilghman
T
D000448:Aldicarb / Q000633:toxicity*; D000818:Animals; D004784:Environmental Monitoring; D005399:Fishes; D007306:Insecticides / Q000633:toxicity*; D007448:Invertebrates / Q000187:drug effects; D018570:Risk Assessment / Q000379:methods*; D014481:United States
D007306:Insecticides; D000448:Aldicarb