Lithium an emerging contaminant: bioavailability, effects on protein expression, and homeostasis disruption in short-term exposure of rainbow trout.

Worldwide production of lithium (Li) has increased dramatically during the past decade, driven by the demand for high charge density batteries. Information about Li in the aquatic environment is limited. The present study was designed to explore the effects of Li in rainbow trout (Oncorhynchus mykiss). Juvenile trout were exposed to a nominal concentration of 1.0mg Li/L in three separate exposures. Major ion concentrations were measured in brain and plasma by ion chromatography. Plasma proteins and fatty acids were measured by HPLC-MS/MS. Lithium accumulated in the brain and plasma. Arachidonic acid was elevated in plasma after 48h. Elevated concentrations of Li in brain were associated with depressed concentrations of sodium, magnesium, potassium and ammonium relative to the control. In plasma, sodium and calcium were also depressed. Several changes occurred to plasma proteins corresponding to Li exposure: inhibition of prostaglandin synthase (Ptgs2), increased expression of copper transporting ATP synthases, and Na(+)/K(+) ATPase. To our knowledge, ours is the first study to demonstrate elevated Li concentrations in fish brain, with associated effects on ion regulation.