Removal of urban-use insecticides in a large-scale constructed wetland.

Water treatment and reuse initiatives are essential to combat declining water supplies in a changing climate, especially in arid and semi-arid regions. Pollution of water resources intensifies the search for strategies to provide water for potable and non-potable reuse that mitigates detrimental ecological and human health effects. Fipronil and synthetic pyrethroids are common urban-use insecticides that exert aquatic toxicity at trace levels and have been often found in urban surface streams.

Metabolomic Profiles in the Brains of Juvenile Steelhead () Following Bifenthrin Treatment.

The pyrethroid insecticide, bifenthrin, is frequently measured at concentrations exceeding those that induce acute and chronic toxicity to several invertebrate and fish species residing in the Sacramento-San Joaquin Delta of California. Since the brain is considered to be a significant target for bifenthrin toxicity, juvenile steelhead trout () were treated with concentrations of bifenthrin found prior to (60 ng/L) and following (120 ng/L) major stormwater runoff events with nontargeted metabolomics used to target transcriptomic alterations in steelhead brains following exposure. Predicted responses were involved in cellular apoptosis and necrosis in steelhead treated with 60 ng/L bifenthrin using the software Ingenuity Pathway Analysis.

The use of non-targeted metabolomics to assess the toxicity of bifenthrin to juvenile Chinook salmon (Oncorhynchus tshawytscha).

An increase in urban and agricultural application of pyrethroid insecticides in the San Francisco Bay Estuary and Sacramento San Joaquin Delta has raised concern for the populations of several salmonids, including Chinook salmon (Oncorhynchus tshawytscha). Bifenthrin, a type I pyrethroid, is among the most frequently detected pyrethroids in the Bay-Delta watershed, with surface water concentrations often exceeding chronic toxicity thresholds for several invertebrate and fish species. To better understand the mechanisms of bifenthrin-induced neurotoxicity, juvenile Chinook salmon were exposed to concentrations of bifenthrin previously measured in the Delta.

Inference of Organophosphate Ester Emission History from Marine Sediment Cores Impacted by Wastewater Effluents.

Organophosphate esters (OPEs) have been in use as flame retardants for many decades, with their actual usage varying over time. Knowledge of the emission history of OPEs is valuable for improving our prediction of their environmental loadings and associated risks. In this study, concentrations and compositions of 10 OPEs were measured in three dated sediment cores from the Palos Verdes Shelf (PVS) off the coast of Los Angeles, which has been impacted by wastewater treatment plant (WWTP) effluents for over a century.

Fiproles in urban surface runoff: Understanding sources and causes of contamination.

Urban-use pesticides present a unique risk to non-target organisms in surface aquatic systems because impervious pavement facilitates runoff that may lead to serious contamination and ensuing aquatic toxicity. Fipronil is an insecticide used at high rates in urban environments, especially in regions such as California. This compound and its biologically active degradation products have been detected in urban runoff drainage and downstream surface water bodies at concentrations exceeding toxicity thresholds for sensitive aquatic invertebrates, necessitating a better understanding of the runoff sources and causes of this contamination at sites of application.

Development of passive samplers for in situ measurement of pyrethroid insecticides in surface water.

Pyrethroid insecticides are widely used in urban environments, and their occurrence has been recently associated with aquatic toxicity in urban surface streams. Synthetic pyrethroids are strongly hydrophobic compounds, highlighting the importance of the freely dissolved concentration (C), rather than the total chemical concentration, for better prediction of potential effects in aquatic ecosystems. The goal of this study was to develop a simple, robust and field-applicable passive sampling methodology that may be used for in situ monitoring of trace levels of pyrethroids in surface water.