Dietary uptake and biological effects of decabromodiphenyl ether in rainbow trout (Oncorhynchus mykiss)

Dietary uptake and effects of decabromodiphenyl ether (DeBDE), a widely used flame retardant, were studied in rainbow trout. Fish were fed for 16, 49, or 120 days with control or DeBDE-treated food (7.5-10 mg of DeBDE/kg of body weight/day). One group was fed DeBDE for 49 days and then control diet for 71 days to study depuration. Chemical analyses were performed using GC/MS(ECNI). Several physiological and biochemical variables were also measured. DeBDE concentrations in muscle increased from <0.6 ng/g of fresh weight to 38 (±14) ng/g after 120 days. Corresponding liver concentrations were <5 and 870 (±219) ng/g of fresh weight. Several hexa- to nonabromodiphenyl ethers, present in both liver and muscle, increased in concentration with exposure length. These congeners originate from metabolism of DeBDE and/ or selective uptake of minor components in the DeBDE product. After depuration- , DeBDE concentrations declined significantly, but concentrations of some lower brominated congeners were unaffected. Liver body index and plasma lactate concentrations were higher in fish exposed for 120 days and in the depuration group, indicating delayed chronic effects, possibly from lower brominated congeners. DeBDE uptake (0.02-0.13%) and possible metabolism seem not to be major sources of tetra- and pentabromodiphenyl ethers found in wild fish.