Influence of Salinity on The Partitioning Behavior of Six Commonly Used Pesticides in Fish Eggs.

Salinity has been reported to impact the octanol-water partition coefficient of organic contaminants entering aquatic ecosystems. However, limited data is available on the impacts of salinity on their partitioning from the aqueous phase to adjacent organic compartments. The pesticides bifenthrin, chlorpyrifos, dicloran, myclobutanil, penconazole, and triadimefon were used to investigate the effects of salinity on their partitioning to capelin (Mallotus villosus) eggs in 5 PSU vs 25 PSU artificial seawater (ASW). The partitioning coefficient was significantly higher in 25 PSU vs 5 PSU ASW for bifenthrin, chlorpyrifos, dicloran, penconazole, and triadimefon by 31%, 28%, 35%, 28%, and 20%, respectively, while for myclobutanil there was no significant difference. Moreover, pesticide partitioning to store-bought capelin eggs was consistent with the partitioning observed for the standard assay species, inland silversides (Menidia beryllina) eggs, after partitioning between the eggs and exposure solution had reached a state of equilibrium. This research illustrates the importance of considering the influence of salinity on the environmental partitioning and fate of hydrophobic organic contaminants in aquatic ecosystems.