MP10 PCB Toxicity in Aquatic Organisms- Endocrine Effects
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(LER-1117-643474) Effects of aqueous exposure to Aroclor 1254 on smolt development and immune function in Atlantic salmon, Salmo salar.

Lerner, D^{1, 2}, Iwanowicz, L^{1, 3}, Blazer, V³, McCormick, S², ¹ University of Massachsuetts, Amherst, MA, USA² USGS, Leetown Science Center, Conte Anadromous Fish Research Center, Turners Falls, MA, USA³ USGS, Leetown Science Center, National Fish Health Research Laboratory, Kearneysville, WV, USA

ABSTRACT- PCBs exist as persistent organic pollutants in numerous river systems in the United States and are implicated as endocrine disruptors and immunomodulators. Here we investigate the effects of aqueous PCB exposure (1 or 10 ppb Aroclor 1254) on plasma hormone concentrations, changes in osmoregulatory capacity, and behavior associated with smolt development and the mitogen-stimulated lymphoproliferative response of anterior kidney leukocytes in Atlantic salmon. Fish were exposed as smolts for 21 days and examined immediately after exposure, or exposed as post-hatch larvae for 21 days and examined 15 months after exposure. Plasma concentrations of cortisol, growth hormone, insulin-like growth factor I, and thyroid hormones were not significantly impacted, however exposure to 10 ppb Aroclor during smolting reduced gill Na, K-ATPase activity, plasma chloride concentration, and seawater preference. The proliferative response to the T cell mitogens CON A and PHA-P was significantly increased in smolts exposed to 10 ppb, and the PHA-P response was significantly increased in the 1 ppb group. In fish treated as larvae and tested 15 months later, the PHA-P sensitive populations exhibited elevated proliferation in the 1 and 10 ppb groups while the PWM response was significantly increased only in the 10 ppb group. These results suggest that the effects of Aroclor 1254 on immune function are disassociated from endocrine factors critical to smolting.

Key words: immunomodulation, endocrine disruption, osmoregulation, behavior