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Characterizing aquatic ecological risks from pesticides using a diquat dibromide case study. I. Probabilistic exposure estimates
Author(s) -
Ritter Amy M.,
Shaw Jennifer L.,
Williams W. Martin,
Travis Kim Z.
Publication year - 2000
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620190330
Subject(s) - diquat , environmental science , pesticide , sediment , environmental chemistry , aquatic plant , hydrology (agriculture) , chemistry , ecology , biology , macrophyte , geology , geotechnical engineering , paleontology , biochemistry , paraquat
Diquat dibromide (6,7‐dihydrodipyrido[1,2‐a:2′,1′‐c] pyrazinediium dibromide; diquat) is one of the few herbicides registered for direct application to water systems in the United States to control noxious aquatic weeds. The dissipation of diquat dibromide in aquatic environments is highly dependent on the hydrodynamic and physicochemical characteristics of the receiving water body. Computer simulations (EXAMSII) were conducted to evaluate the variability of diquat cation dissipation in farm ponds, lakes, and canals following applications to control aquatic weeds across the United States. Within each scenario, probabilities were assigned to varying values for physical properties (velocity, dispersion, suspended sediment concentrations, bed sediment properties, and plant biomass) using a joint probability method, and the results were expressed as spatially and temporally explicit cumulative probability distributions by water‐body type on a regional scale. The results showed that the dissipation of diquat cation in water was very rapid, with the highest exposure concentrations (90th percentile) predicted to be 0.194 mg/L diquat cation 1 h after treatment and typically reaching 0.01 mg/L by 96 h.