Seasonal Variation in Radiocesium Levels of Largemouth Bass (Micropterus Salmoides): Implications for Humans and Sensitive Wildlife Species

Abstract

Abstract-To examine seasonal variation in levels of radiocesium ( 137 Cs) within largemouth bass (Micropterus salmoides; N ϭ 589), fish were collected monthly over a one-year period from an abandoned reactor cooling reservoir. Month of collection, sex, age, and body mass (log transformed) were all significant factors influencing 137 Cs concentrations. Levels of 137 Cs reached a peak in late winter/early spring (February/March), and minimum values occurred in the fall (October). An asymmetric sawtooth model with a four-month period of increase and an eight-month period of decrease fit the data for monthly 137 Cs values significantly better than symmetric sinusoidal and sawtooth models. The mean concentration of 137 Cs for bass collected during all months was 7.09 Bq/g wet mass. All individuals examined, regardless of month, sex, age, or body mass, had 137 Cs levels (2.95-12.60 Bq/g) that were much higher than the maximum level (0.60 Bq/g wet mass) generally considered safe for human consumption. Radiocesium is relatively long-lived within this reservoir and will continue to remain an important issue in risk assessments for both humans and wildlife species.

Flow cytometric analysis of red-eared slider turtles (Trachemys scripta) from Tar Creek Superfund Site

“…Lamb et al (1995) reported that CVs may undergo temporary fluctuations due to changes in population structure or metabolic responses to contaminants in the organisms of interest. Studies of cesium contamination showed that patterns of uptake and excretion in largemouth bass (Micropterus salmoides) and yellow-bellied slider turtles (Pseudemys scripta) were asymmetrical and were more dependent upon individual patterns of activity and physical condition than size (Peters and Brisbin 1988;Peles et al 2000). Although toxicokinetics of heavy metals and radionuclides differ, occurrence of variation in CV through time suggests that physiological processes, such as metabolic rate, possibly alter effects of contaminants on exposed populations.…”

Contrasting cesium dynamics in neighboring deep and shallow warm-water reservoirs

“…Numerous studies of 137 Cs in biota were also performed in both Par Pond and Pond B (Domby et al, 1978;Newman and Brisbin, 1990;Whicker et al, 1990;Kelly and Pinder, 1996;McCreedy et al, 1997), and some seasonal patterns in the 137 Cs concentrations in biota appeared to be related to the seasonal cycle of concentrations in the water column (Holloman et al, 1997;Peles et al, 2000). Because these studies were conducted >20 years after the main release of 137 Cs into the lakes (from 1961through 1964Ashley and Zeigler, 1980), they were largely limited to assessments of concentration ratios for systems already at or near steady state.…”

The influence of a whole-lake addition of stable cesium on the remobilization of aged 137Cs in a contaminated reservoir

“…Subsequent desorption of 137 Cs from sediments can occur and contribute to the Cs content of water (Alberts et al, 1979;Evans et al, 1983;Alberts et al, 1987) and biota (Kelly and Pinder, 1996;Holloman et al, 1997;Peles et al, 2000). Cesium desorption is particularly evident in systems with (1) a large proportion of clays such as kaolinite that desorb Cs more readily than 2:1 layered clays such as illite (Comans et al, 1991;Maguire et al, 1992;de Koning et al, 2000;Hinton et al, 2001;Krumhansl et al, 2001) and (2) periods of anoxia associated with the production or release of monovalent cations that compete with Cs C for sorption sites on the sediments (Sholkovitz, 1985;Comans et al, 1989;Dominik and Span, 1992).…”