Pyrethroids in Southern California coastal sediments

Abstract

Little is known about pyrethroid fate and effects in estuarine and marine environments. In the present study, the extent and magnitude of pyrethroids in coastal embayments of the Southern California Bight (SCB), USA, were assessed. Using a stratified probabilistic design, 155 sediment samples were collected from four embayment habitats (estuaries, marinas, open bays, and ports) and analyzed for eight common-use pyrethroids. Total pyrethroid concentrations ranged from less than 0.5 to 230 µg/kg dry weight (area-weighted mean concentration=5.1 ± 3.1 µg/kg) and were detected in 35% of the total SCB embayment area. Estuaries and marinas had the greatest areal extent of detectable concentrations (up to 65%) and the greatest area-weighted mean concentrations (22.1 ± 26.5 µg/kg). Sites with the greatest pyrethroid concentrations were located near sources of runoff from urban watersheds. Bifenthrin and cyfluthrin were detected in 32 and 15% of all samples, respectively, whereas the other six pyrethroids were detected in ≤ 5% of samples. Permethrin and bifenthrin had the highest concentrations at 132 and 65 µg/kg. Toxic units estimated for the marine amphipod Eohaustorius estuarius ranged from 0 to 5.8, exceeding unity in 9 and 32% of the total and estuary habitat areas, respectively, and were not correlated with mortality, suggesting that other factors (e.g., co-occurring contaminants, reduced bioavailability) may affect the predictive capability using a single test species.

Addition of contaminant bioavailability and species susceptibility to a sediment toxicity assessment: Application in an urban stream in China

“…When calculated TU values were in the range of 0.5e5, sediment toxicity to H. azteca varied extensively; therefore, it was difficult to predict toxicity of the sediments with contaminants at concentrations within this range. This is consistent to previous finding by Lao et al (2012) who suggested that the predicative ability of TUs to sediment mortality may be poor when TU values were between 1 and 5. Although Spyr-TU > 5 usually corresponded to toxic sediment to the amphipods (Lao et al, 2012), there were some exceptions.…”

“…This is consistent to previous finding by Lao et al (2012) who suggested that the predicative ability of TUs to sediment mortality may be poor when TU values were between 1 and 5. Although Spyr-TU > 5 usually corresponded to toxic sediment to the amphipods (Lao et al, 2012), there were some exceptions. For example, sediment S9 (the present study) and a sediment from Dallas, TX, US (Kuivila et al, 2012) had Spyr-TUs of 5.98 and 13.3, respectively, but mortality to H. azteca was only 58 and 27%, respectively.…”

“…Consequently, the traditional TU approach may overpredict sediment toxicity. For example, over-predication of toxicity has been reported for the amphipods Hyalella azteca and Eohaustorius estuarius using pyrethroid-derived TUs at some sites (Amweg et al, 2006;Kuivila et al, 2012;Lao et al, 2012).…”

Comparison of national and regional sediment quality guidelines for classifying sediment toxicity in California

“…For example, all of the SQG approaches in common use are based on an outdated list of priority and legacy pollutants (e.g., PCBs, trace metals, PAHs, chlorinated pesticides) that does not include current use pesticides. These pesticides, including pyrethroids (e.g., bifenthrin) and organophosphates (e.g., chlorpyrifos), have widespread occurrence in coastal watersheds, bays, and estuaries (Delgado‐Moreno et al 2011; Lao et al 2012). Pyrethroids in particular have been identified as a dominant cause of sediment toxicity in California streams and estuaries (Bay et al 2011; Holmes et al 2008).…”

Treated wastewater effluent as a source of pyrethroids and fipronil at Todos Santos Bay, Mexico: Its impact on sediments and organisms

“…This trend is unexpected because of the strong affinity of pyrethroids with organic matter and fine grain size fraction (<63 μm) and has been observed on other organic pollutants that are highly hydrophobic, such as organochloride pesticides, polychlorinated biphenyls, or polycyclic aromatic hydrocarbons . Therefore, this pattern could be explained by the proximity to runoff sources, mainly to WWTP effluents, where urban and agricultural activities could have a bigger impact in the study area and can be reported in the northern area of the Southern California Bight .…”