Dietary exposure of juvenile rainbow trout (Oncorhynchus mykiss) to 1,2-bis(2,4,6-tribromophenoxy)ethane: bioaccumulation parameters, biochemical effects, and metabolism.
Juvenile rainbow trout (Oncorhynchus mykiss) were exposed in the laboratory to an environmentally relevant dose of 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) via their diet for 49 days, followed by 154 days of untreated food to examine bioaccumulation parameters, potential biochemical effects, and metabolic products. There was a linear increase in the amount of BTBPE in fish during the uptake phase of the experiment, and an uptake rate constant of 0.0069 +/- 0.0012 (arithmetic mean +/- 1 x standard error) nmoles per day was calculated. The elimination of BTBPE from the fish obeyed first-order depuration kinetics (r2 = 0.6427, p < 0.001) with a calculated half-life of 54.1 +/- 8.5 days. The derived biomagnification factor of 2.3 +/- 0.9 suggests that this chemical has a high potential for biomagnification in aquatic food webs. Debrominated and hydroxylated metabolites were not detected in liver extracts and suggest that either biotransformation or storage of BTBPE-metabolites in the hepatic system of fish is minor or that our exposure time frame was too short. Similar concentrations of circulating thyroid hormones, liver deiodinase enzyme activity, and thyroid glandular histology suggest that BTBPE is not a potent thyroid axis disruptor.
Tomy
Gregg T
GT
Department of Fisheries and Oceans, Freshwater Institute, Winnipeg, Manitoba R3T 2N6, Canada. tomyg@dfo-mpo.gc.ca
Palace
Vince P
VP
Pleskach
Kerri
K
Ismail
Nargis
N
Oswald
Tyler
T
Danell
Robert
R
Wautier
Kerry
K
Evans
Bob
B
D000818:Animals; D001969:Bromobenzenes / Q000493:pharmacokinetics*; D004032:Diet; D017686:Oncorhynchus mykiss / Q000254:growth & development / Q000378:metabolism; D012015:Reference Standards; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics*
D001969:Bromobenzenes; D014874:Water Pollutants, Chemical; C081014:1,2-bis(2,4,6-tribromophenoxy)ethane