The persistence, bioaccumulation, and inherent toxicity of two organophosphate flame retardants tris (2-butoxyethyl) phosphate and tris (1-chloro-2-propyl) phosphate in juvenile rainbow trout (Oncorhynchus mykiss)
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Abstract
Juvenile rainbow trout were exposed to two organophosphate flame retardants: tris(2-butoxyethyl) phosphate (TBOEP) and tris(1-chloro-2-propyl) phosphate (TCIPP), at environmentally relevant concentrations via their diet to determine their bioaccumulation and potential endocrine effects. Two groups of fish were fed food fortified with known amounts of TBOEP or TCIPP, while a third group was fed unfortified food. TBOEP did not bioaccumulate appreciably and concentrations were close to the method detection limit. Bioaccumulation of TCIPP was linear during the uptake phase and reached a peak concentration of 3.6±1.3 pmole/g. TCIPP followed first-order depuration kinetics, from which we calculated a half-life of 50.2±19.3 days. The biomagnification factor was calculated to be 0.8±0.4, indicating that TCIPP has a low potential to biomagnify in aquatic food webs. Neither parent nor suspected metabolites were measureable in the liver on day 49. There were some significant differences in the amounts of estradiol, testosterone (T), cortisol, and thyroid (T4 and T3) hormones in the plasma of fish from the treated and untreated groups. However, there were no consistent trends among any of the hormones. We did however observe a significant decrease (p< 0.05) in total T4 and T at day 49 in TCIPP exposed fish relative to the reference fish.