Pyrethroid insecticide concentrations and toxicity in streambed sediments and loads in surface waters of the San Joaquin Valley, California, USA

Abstract

Pyrethroid insecticide use in California, USA, is growing, and there is a need to understand the fate of these compounds in the environment. Concentrations and toxicity were assessed in streambed sediment of the San Joaquin Valley of California, one of the most productive agricultural regions of the United States. Concentrations were also measured in the suspended sediment associated with irrigation or storm-water runoff, and mass loads during storms were calculated. Western valley streambed sediments were frequently toxic to the amphipod, Hyalella azteca, with most of the toxicity attributable to bifenthrin and cyhalothrin. Up to 100% mortality was observed in some locations with concentrations of some pyrethroids up to 20 ng/g. The western San Joaquin Valley streams are mostly small watersheds with clay soils, and sediment-laden irrigation runoff transports pyrethroid insecticides throughout the growing season. In contrast, eastern tributaries and the San Joaquin River had low bed sediment concentrations (<1 ng/g) and little or no toxicity because of the preponderance of sandy soils and sediments. Bifenthrin, cyhalothrin, and permethrin were the most frequently detected pyrethroids in irrigation and storm water runoff. Esfenvalerate, fenpropathrin, and resmethrin were also detected. All sampled streams contributed to the insecticide load of the San Joaquin River during storms, but some compounds detected in the smaller creeks were not detected in the San Joaquin River. The two smallest streams, Ingram and Hospital Creeks, which had high sediment toxicity during the irrigation season, accounted for less than 5% of the total discharge of the San Joaquin River during storm conditions, and as a result their contribution to the pyrethroid mass load of the larger river was minimal.

Sub-lethal toxicity of environmentally relevant concentrations of esfenvalerate to Chironomus riparius

“…Environmental concentrations up to 0.66 mg/L ESF have been reported in water samples (Brady et al, 2006;Forbes and Cold, 2005), and it is frequently found in sediments and organic matter in aquatic systems at concentrations that are toxic to aquatic organisms (Allinson et al, 2015;Domagalski et al, 2010;EFSA, 2014;Ensminger et al, 2011;Fairchild et al, 1992;Rasmussen et al, 2013;Weston et al, 2013). However, investigations linking biochemical to life-history effects on aquatic sediment-dwelling invertebrates exposed to pyrethroids are still needed.…”

“…This widespread application leads to the common detection of pyrethroids in sediments of streams and lakes (Domagalski et al, 2010;Kuivila et al, 2012;Weston et al, 2009).…”

Environmental Modeling and Exposure Assessment of Sediment-Associated Pyrethroids in an Agricultural Watershed

“…Method detection limits were taken from the respective studies. LC50 values were compiled by Domagalski et al [29] from the literature.…”

Use-Exposure Relationships of Pesticides for Aquatic Risk Assessment

“…Median lethal concentration (LC50) values for sediment toxicity are usually reported on an OC-normalized basis. For example, Hyalella azteca 10-day LC50 values for pyrethroids are typically reported at 1% OC, as compiled by Domagalski et al [40]. To match the toxicity data, PRZM-predicted concentrations of pesticide in eroded sediment were normalized by OC1 defined in each scenario (Table 3).…”