SREL Reprint #3829

Uptake and elimination of 137Cs in aquatic biota inhabiting a contaminated effluent canal

Kathryn A. Quinlin1,2, Danielle Hill2,3, Xiaoyu Xu1,2, and James C. Beasley1,2

1Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
2Savannah River Ecology Lab, University of Georgia, Aiken, SC, 29802, USA
3Australian Rivers Institute, and School of Environment and Science, Griffith University,
Southport, Queensland, Australia

Abstract: Radiocesium (137Cs) is among the most prevalent and concerning radionuclide released from anthropogenic activities due to its relatively slow decay time and high bioavailability. Numerous studies have reported activity concentrations of 137Cs in exposed biota, but few have assessed detailed toxicokinetics. The objective of our study was to quantify and compare the uptake and elimination of 137Cs in aquatic taxa from multiple classes with different ecological roles inhabiting a canal contaminated from nuclear production activities on the Savannah River Site in South Carolina, USA. We tracked accumulation and elimination of 137Cs in four understudied aquatic species: one aquatic macrophyte [American white water lily (Nymphae odorata), two benthic associated omnivorous species (American bullfrog (Lithobates catesbeianus) and red swamp crayfish (Procambarus clarkii), and one pelagic carnivorous fish (Eastern mosquitofish (Gambusia holbrooki)]. We monitored accumulation of 137Cs from initial exposure until equilibrium for biota restricted within the canal and subsequently tracked elimination of 137Cs over time by moving organisms from the canal to a nearby reference pond. Results indicated bullfrog tadpoles reached 95% equilibrium in approximately 9 days, the fastest among the species evaluated. After bullfrog tadpoles, the next fastest time to equilibrium was achieved by red swamp crayfish (51 days) followed by mosquitofish (86 days). At equilibrium, bullfrog tadpoles were found to have similar 137Cs activity concentrations to mosquitofish (3.16 and 3.57 Bq/g, respectively), and both were significantly higher than red swamp crayfish (1.77 Bq/g). For elimination, we found biological half-lives to range between 8 and 43 days with bullfrog tadpoles eliminating 137Cs the fastest followed by water lilies, mosquitofish, and red swamp crayfish. Overall, we found the uptake and elimination of 137Cs to vary widely among our studied species, but benthic organisms are not at an increased risk to accumulate 137Cs compared to organisms in less frequent contact with the sediment.

Keywords: Benthic organism; Bioaccumulation; Bioindicator; Elimination; Radiocesium; Toxicokinetics

SREL Reprint #3829

Quinlin, K. A., D. Hill, X. Xu, and J. C. Beasley. 2025. Uptake and elimination of 137Cs in aquatic biota inhabiting a contaminated effluent canal. Journal of Environmental Radioactivity 287(107697).

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).