Occurrence and Probable Sources of Urban-Use Insecticides in Marine Sediments off the Coast of Los Angeles

Abstract

Insecticides such as pyrethroids and fipronil are used in large amounts in both agricultural and urban settings and have the potential to elicit toxicity to nontarget aquatic organisms. In California, like in many other regions of the world, urban centers are located along the coast, and it is documented that urban-use insecticides enter the marine environment, where little is known about their occurrence and consequences. In this study, we measured the spatial distribution of pyrethroids and fipronil (and its metabolites) on the Palos Verdes Shelf off the coast of Los Angeles. Total pyrethroid levels ranged from nd to 170 μg/kg (dry weight), and fipronil sulfide levels ranged from 1.8 to 5.6 μg/kg. Two pyrethroids were traced to wastewater effluent discharge, while two others and fipronil sulfide were traced to to surface runoff. Toxicity units (TUs) were estimated for benthic invertebrates, which ranged from no toxicity (nt) to 146 for total pyrethroids, and 0.09 to 1.6 and 4.2 to 75 for fipronil sulfide, depending on the indicator species. Therefore, near-shore deposition of urban-use insecticides due to wastewater discharge and surface runoff poses a significant risk to marine benthic invertebrates and highlights the importance of monitoring near-shore ocean environments and developing mitigation strategies to reduce seaward movement.

Suspect and Nontarget Screening for Contaminants of Emerging Concern in an Urban Estuary

“…The time series of samples also suggests that localized impacts are persistent and can lead to chronic exposure risks in marine ecosystems. Thus, nearshore marine surface waters in urban and peri-urban regions seem to be affected by both spatially variable but relatively continuous wastewater-derived CECs and contaminants from localized sources linked to urbanization and industrial land uses …”

“…Thus, nearshore marine surface waters in urban and peri-urban regions seem to be affected by both spatially variable but relatively continuous wastewater-derived CECs and contaminants from localized sources linked to urbanization and industrial land uses. 97 Environmental Implications. Characterizing CEC occurrence and risk in urban and peri-urban estuarine environments is critical to protect their valuable ecological function.…”

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

“…The use of pyrethroid insecticides for urban and agricultural applications has amounted to a total of 8200 tons of active ingredients applied in 2014 worldwide, reflecting a shift from organophosphate insecticides . A commonly detected pyrethroid, bifenthrin, has been reported in 95% of sediment samples collected in Southern California and represents the most prevalent pyrethroids measured in collected water samples throughout California. − Concentrations of bifenthrin measured in surface water have been detected above the levels that induce acute and chronic toxicity to several invertebrate and fish species. ,, The Sacramento-San Joaquin Delta Estuary provides an important fish nursery and spawning ground to many residential and anadromous fish species. Reductions in pelagic fish, such as steelhead trout (Oncorhynchus mykiss), have been occurring over the last few decades, coinciding with the increased use of pyrethroid insecticides. − Bifenthrin concentrations detected within the Sacramento-San Joaquin Delta Estuary, some exceeding 3 μg/L, are well above the concentrations previously reported to impair proper neuroendocrine function in salmonids in laboratory studies (≤1.5 μg/L). − …”

Lipid Metabolic Disorder Induced by Pyrethroids in Nonalcoholic Fatty Liver Disease of Xenopus laevis

“…8 Moreover, up to 170 μg/kg dry weight (dw) pyrethroids from wastewater effluent discharge and surface runoff were found on the Palos Verdes Shelf off the coast of Los Angeles. 9 In China, SPs were also detected in both overlying water and surface sediment samples of Guangzhou waterways. 10 SPs were detectable in all sediment samples of Guangzhou reach of the Pearl River with concentrations up to 61.2 μg/kg dw.…”

“…Moreover, SPs have been dramatically detected in 74–100% of samples collected from water and sediments on the southern California coast, with a maximum level of 1100 μg/kg . Moreover, up to 170 μg/kg dry weight (dw) pyrethroids from wastewater effluent discharge and surface runoff were found on the Palos Verdes Shelf off the coast of Los Angeles . In China, SPs were also detected in both overlying water and surface sediment samples of Guangzhou waterways .…”