Characterizing Dependence of Pesticide Load in Surface Water on Precipitation and Pesticide Use for the Sacramento River Watershed

Abstract

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.

Daily Variation of Pesticides in Surface Water of a Small River Flowing Through Paddy Field Area

“…For instance, the daily maximum concentrations of buprofezin and fenitrothion on August 7, and flutolanil and phthalide on August 8 were observed at 12 p.m. and 2 p.m., and at 6 p.m. and 10 p.m., respectively. Although the pesticide concentrations could increase with rainfall due to the runoff (Fox et al 2007;Maeda et al 2008) or pesticides in the rain (Guo et al 2004), the rainfall events on August 9 and 12 did not remarkably affect the increases in the pesticide concentrations. Table 2 shows the four kinds of concentrations of the target pesticides for the daily representative values from August 7 to 12.…”

Variation of 4,5,6,7-Tetrachlorophthalide in Water After Aerial Application to Rice Cultivation Area

“…These runoffs were caused by the rainfall (35 mm) of August 12. Transport of the pesticides by surface runoff during the rainfall events is a major process contributing to the pesticide contamination in the rivers (Fox et al 2007;Guo et al 2004). The runoffs into drainage channels 1, 2 and the Anno River on August 13 were estimated to be 29, 75 and 690 g, which were 40%, 23% and 15% of the total runoff amounts during the 137 days investigation (Table 3), respectively.…”

Completing the Picture: The Challenges of Bringing “Consumption” into the Population–Environment Equation

“…Research efforts are underway to develop novel protein foods (Zhu, 2003), but given the degree to which food preferences are embedded in culture, it is unclear how successful such programs will be in convincing households to shift to new food types. Further, high input, intensive, commercial agricultural is a dominant determinant of freshwater quantity and quality (Batista, Silva, Galhardo, Viviana, & Cerejeira, 2002;Guo et al, 2004;Hall, Schreier, & Berka, 2001;Hunt et al, 1999). Duchin (2003Duchin ( , 1997 and Reusswig, Lotze-Campen, & Gerlinger (2003) have proposed the use of household typologies developed by market research firms for the understanding of household types and their environmentally significant consumption patterns.…”