Exposures of Aquatic Organisms to the Organophosphorus Insecticide, Chlorpyrifos Resulting from Use in the United States - Reviews of Environmental Contamination and Toxicology - page 100

Fig. 9 Estimated average annual chlorpyrifos loss in runoff water for the Sacramento River, San
Joaquin River, and Bay Delta estuary watersheds of California (see SI for a color version of this
Figure)
Average annual mass loadings (Fig. 9 ) ranged from as little as 0.45 g to 18.5 kg per
Public Land Survey Section (PLSS) per year. The largest annual mass loadings
from runoff and erosion were predicted in southern Yuba County of the Sacramento
Valley watershed and San Joaquin, Madera, and Stanislaus counties of the San