Interim Results From a Study of the Impacts of Tin(ii) Based Mercury Treatment in a Small Stream Ecosystem: Tims Branch, Savannah River Site

Abstract

) collecting fish from a beaver pond using a backpack shocker; typical specimen of redfin pickerel; scanning electron micrograph of flocculated tin oxide particulate collected from treated water exiting the M1 air stripperParticipating Organizations: Savannah River National Laboratory, University of Georgia Savannah River Ecology Laboratory, Oak Ridge National Laboratory, and the Applied Research Center at Florida International University Printed in the United States of America Prepared For U.S. Department of Energy Office of Environmental Management Office of Site Restoration Soil and Groundwater (EM-12) DISCLAIMERThis work was prepared under an agreement with and funded by the U.S. Government. While the authors have taken care in the preparation of this report, neither the U. S. Government or its employees, nor any of its contractors, subcontractors or their employees, makes any express or implied: 1. warranty or assumes any legal liability for the accuracy, completeness, or for the use or results of such use of any information, product, or process disclosed; or 2. representation that such use or results of such use would not infringe privately owned rights; or 3. endorsement or recommendation of any specifically identified commercial product, process, or service. Any views and opinions of authors expressed in this work do not necessarily state or reflect those of the United States Government, or its contractors, or subcontractors. Executive SummaryA research team is assessing the impacts of an innovative mercury treatment system in Tims Branch, a small southeastern stream. The treatment system, installed in 2007, reduces and removes inorganic mercury from water using tin(II) (stannous) chloride addition followed by air stripping. The system results in discharge of inorganic tin to the ecosystem. This screening study is based on historical information combined with measurements of contaminant concentrations in water, fish, sediment, biofilms and invertebrates. Initial mercury data indicate that first few years of mercury treatment resulted in a significant decrease in mercury concentration in an upper trophic level fish, redfin pickerel, at all sampling locations in the impacted reach. For example, the whole body mercury concentration in redfin pickerel collected from the most impacted pond decreased approximately 72% between 2006 (pre-treatment) and 2010 (post-treatment).Over this same period, mercury concentrations in the fillet of redfin pickerel in this pond were estimated to have decreased from approximately 1.45 g/g (wet weight basis) to 0.45 g/g -a decrease from 4.8x to 1.5x the current EPA guideline concentration for mercury in fillet (0.3 g/g). Thermodynamic modeling, scanning electron microscopy, and other sampling data for tin suggest that particulate tin (IV) oxides are a significant geochemical species entering the ecosystem with elevated levels of tin measured in surficial sediments and biofilms. Detectable increases in tin in sediments and biofilms extended approximately 3km from the discha...

Update to agency for toxic substances and disease registry 2012 report on assessment of biota exposure to mercury originating from Savannah River Site.

“…All of the data from the initial phase of work were reported in the Interim Results from a Study of the Impacts of Tin (II) Based Mercury Treatment in a Small Stream Ecosystem: Tims Branch, (Looney et al 2012).…”

“…In 2012, a multi-organizational research team completed the initial phase of research in a special study of Tims Branch (Looney, et al, 2012). The project aimed to evaluate and quantify the impacts of an innovative, inexpensive treatment system that removes mercury from water.…”

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

“…Additions of SnCl2 reduce and mobilize Hg in order to volatilize the trace metal in the air stripper. These remediation efforts showed a reduction of Hg concentrations in redfin pickerel (Esox americanus) of up to 72 % in samples collected in 2010 when compared to those sampled in 2006 before the addition of SnCl2 (Looney et al 2012).…”

“…Specifically, Al, Cr, Cu, Ni, Pb, and U are considered COPCs for watershed due to bioavailability and the transfer factors previously observed (e.g., Pickett et al 1987;Pickett 1990;Batson et al 1996;Punshon et al 2003a, b;Murray et al 2010). Additionally, Hg is considered a COPC due to the history of Hg inputs into the Tims Branch stream system (Looney et al 2012). Although previous work has indicated that COPCs have not entered the terrestrial food web associated with Tims Branch (Reinhart 2003), other ecotoxicological studies have shown that the contamination is present in both the aquatic and transitional wetland communities (Murray et al 2010;O'Quinn 2005;Punshon et al 2003a, b;Sowder et al 1996).…”