Characterizing dependence of pesticide load in surface water on precipitation and pesticide use for the Sacramento River watershed.
Transport of pesticides by surface runoff during rainfall events is a major process contributing to pesticide contamination in rivers. This study presents an empirical regression model that relates pesticide loading over time in the Sacramento River with the precipitation and pesticide use in the Sacramento River watershed. The model closely simulated loading dynamics of diazinon, simazine, and diuron during 1991-1994 and 1997-2000 winter storm seasons. The coefficients of determination for regression ranged from 0.168 to 0.907, all were significant at <0.001. The results of this study provide strong evidence that precipitation and pesticide use are the two major environmental variables dictating the dynamics of pesticide transport into surface water in a watershed. The capability of the statistical model to provide time-series estimates on pesticide loading in rivers is unique and may be useful fortotal maximum daily load (TMDL) assessments.
Environmental Monitoring Branch, Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, California 95812-4015, USA. lguo@cdpr.ca.gov
Lei
L
Guo
Craig E
CE
Nordmark
Frank C
FC
Spurlock
Bruce R
BR
Johnson
Linying
L
Li
J Marshall
JM
Lee
Kean S
KS
Goh
D000383:Agriculture; D002140:California; D011232:Chemical Precipitation; D003976:Diazinon / Q000032:analysis; D004237:Diuron / Q000032:analysis; D005618:Fresh Water / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis*; D011891:Rain; D012044:Regression Analysis; D013997:Time Factors; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
D010575:Pesticides; D014874:Water Pollutants, Chemical; D004237:Diuron; D003976:Diazinon