Trophic dynamics of U, Ni, Hg and other contaminants of potential concern on the Department of Energy’s Savannah River Site

Abstract

The Department of Energy's Savannah River Site is a former nuclear weapon material production and current research facility located in South Carolina, USA. Wastewater discharges from a fuel and nuclear reactor target manufacturing facility released depleted and natural U, as well as other metals into the Tims Branch-Steed Pond water system. We investigated the current dynamics of this system for the purposes of environmental monitoring and assessment by examining metal concentrations, bioavailability, and trophic transfer of contaminants in seven ponds. Biofilm, detritus, and Anuran and Anisopteran larvae were collected and analyzed for stable isotopes (δ (15)N, δ (13)C) and contaminants of potential concern (COPC) with a focus on Ni, U, and Hg, to examine metal mobility. Highest levels of Ni and U were found in biofilms U (147 and 332 mg kg(-1) DW, respectively), while highest Hg levels were found in tadpoles (1.1 mg kg(-1) DW). We found intraspecific biomagnification of COPCs as expressed through stable isotope analysis. Biofilms were the best indicators for contamination and Anuran larvae with the digestive tract removed were the best indicators of the specific bioavailability of the focal metals. Monitoring data showed that baseline δ (15)N values differed between ponds, but within a pond, values were stable throughout tadpole Gosner stage, strengthening the case to use this species for monitoring purposes. It is likely that there still is risk to ecosystem integrity as COPC metals are being assimilated into lower trophic organisms and even low levels of this mixture has shown to produce deleterious effects to some wildlife species.

Heavy metal bioaccumulation in two passerines with differing migration strategies

“…Higher trophic level organisms, such as piscivorous birds and raptors, have been extensively studied and monitored for heavy metals (Battaglia et al, 2005;Lodenius and Solonen, 2013;Movalli, 2000;Solonen and Lodenius, 1990); however, heavy metal contamination from an aquatic source can bioaccumulate to levels sufficient to negatively affect organisms at a lower trophic level (Edwards et al, 2014). Jackson et al (2011) indicated terrestrial songbird reproductive success was reduced in the terrestrial environment surrounding rivers contaminated by heavy metals.…”

Dynamic Responses of Trace Metal Bioaccessibility to Fluctuating Redox Conditions in Wetland Soils and Stream Sediments

“…Soil samples were collected in October 2020 from a riparian wetland in the Tims Branch watershed at the Savannah River Site in Aiken County, South Carolina. The site has flooded and dried several times during the last decade . It lacks surface water during the summer but quickly, within hours, recharges during extreme weather events.…”

“…The site has flooded and dried several times during the last decade. 56 It lacks surface water during the summer but quickly, within hours, recharges during extreme weather events. Tims Branch also experiences high beaver activity causing ponding.…”

Is Long-Term Heavy Metal Exposure Driving Carriage of Antibiotic Resistance in Environmental Opportunistic Pathogens: A Comprehensive Phenomic and Genomic Assessment Using Serratia sp. SRS-8-S-2018

“…Specifically, soils from a highly contaminated site-SRS 101 were serially diluted and spread plated onto LB agar plates supplemented with 5 µg/ml mercuric chloride. Site 101 has been shown to be co-contaminated with a variety of different heavy metals, such as Hg and U (Edwards et al, 2014). Plates were incubated at 30 • C, for 48 hours and colonies that appeared on the plates were further purified resulting in a vigorous Hg-resistant (HgR) strain, labeled as SRS-8-S-2018.…”