Kathryn Kuivila (Former Employee)

This report contains pesticide concentration data for water, and suspended and bed sediment samples collected in April 2003 from twelve sites along the New and Alamo Rivers in the Salton Sea watershed, in southeastern California. The study was done in collaboration with the California State Regional Water Quality Control Board, Colorado River Region, to assess inputs of current-use...

As part of a collaborative study involving the United States Geological Survey Toxics Substances Hydrology Project (Toxics Project) and the University of California, Davis, Bodega Marine Laboratory (BML), water samples were collected at three sites within the San Joaquin River Basin of California and analyzed for dissolved pesticides. Samples were collected during, and immediately after...

Water samples were collected from the Alamo River and the Salton Sea, California, in autumn 1996 and late winter/early spring 1997 and analyzed for dissolved pesticides. The two seasons chosen for sampling were during pesticide application periods in the Imperial Valley. Pesticide concentrations were measured in filtered water samples using solid-phase extraction and analyzed by gas...

Delta smelt abundance in San Francisco Estuary has been declining since 1983. The exposure of delta smelt to toxic pesticides during larval and juvenile life stages may be one possible factor of this decline (Bennett and Moyle 1996; Moyle and others 1996). Although pesticides have been detected in the Delta (MacCoy and others 1995; Kuivila and others 1999), minimal data on pesticide...

Estuaries receive large quantities of suspended sediments following the first major storm of the water year. The first-flush events transport the majority of suspended sediments in any given year, and because of their relative freshness in the hydrologic system, these sediments may carry a significant amount of the sediment-associated pesticide load transported into estuaries. To...

A method of analysis and quality-assurance practices were developed to study the fate and transport of pesticides in the San Francisco Bay-Estuary by the U.S. Geological Survey. Water samples were filtered to remove suspended-particulate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide and the...

Pesticide occurrence and concentrations were evaluated in the San Joaquin River Basin to determine potential sources and mode of transport. Land use in the basin is mainly agricultural. Spatial variations in pesticide occurrence were evaluated in relation to pesticide application and cropping patterns in three contrasting subbasins and at the mouth of the basin. Temporal variability in...

Delta smelt is a threatened species in the San Francisco Bay Estuary. Pesticide toxicity is a possible cause for the need to list this fish (Bennett and Moyle 1996; Moyle and others 1996). Numerous pesticides are transported into the estuary from area rivers (MacCoy and others 1995). However, there are minimal data to document the presence, or absence, of pesticides within delta smelt...

The pesticides molinate, thiobencarb, and carbofuran are applied to rice (Oryza sativa L.) fields in the Sacramento Valley, California, each year during April through June. These pesticides are of concern because of their adverse effects on water quality and their potential adverse effects on aquatic life. Therefore, the California Regional Water Quality Control Board (CRWQCB) mandated...

A laboratory study was used to evaluate the response of select insecticides to toxicity identification evaluation procedures. Fourteen insecticides, one degradation product, and one synergist were spiked into organic-grade water and carried through toxicity identification evaluation procedures. Concentrations of each compound were analyzed by gas chromatography/mass spectrometry. During...

During the study of inputs of sediment-associated pesticides into the San Francisco Bay Estuary, suspended sediments were isolated from large-volume water samples collected over several years at various stations in Suisun Bay and also covering the principal inputs and outlet. The samples were analyzed for 21 pesticides and pesticide degradation products to provide information about the...

The purpose of this study was to develop a twice-a-day sampling strategy for suspended solids concentration at Mallard Island that best reproduces the residual (tidally averaged) near-surface suspended solids concentration computed using the entire time series (96 sampling times per day) for high delta discharge conditions and to use this stratgy for sampling sediment-associated...