Article pubs.acs.org/est
Polybromodiphenyl Ethers and Decabromodiphenyl Ethane in Aquatic Sediments from Southern and Eastern Arkansas, United States Hua Wei,† Azivy Che Aziz-Schwanbeck,‡ Yonghong Zou,§ Margaret B. Corcoran,∥ Armen Poghosyan,∥ An Li,†,* Karl J. Rockne,‡ Erik R. Christensen,§ and Neil C. Sturchio∥ †
School of Public Health, University of Illinois at Chicago, Chicago, Illinois, 2121 West Taylor Sreet, Chicago, Illinois 60612, United States ‡ Department of Civil and Materials Engineering, University of Illinois at Chicago, Chicago, Illinois. § Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin. ∥ Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, Illinois. S Supporting Information *
ABSTRACT: South-central Arkansas (AR) is home to major manufacturing facilities for brominated flame retardant chemicals (BFRs) in the U.S. Unintended release during production may have caused accumulation of the BFRs in the local environment. In this work, sediment cores were collected from six water bodies in AR, including three located close to the BFR manufacturing facilities in El Dorado and Magnolia, to investigate past and recent deposition histories. A total of 49 polybromodiphenyl ethers (PBDEs) and decabromodiphenyl ethane (DBDPE) were detected, with concentrations as high as 57 000 and 2400 ng/g dry weight for decabromodiphenyl ether (BDE209) and DBDPE, respectively. Log−log regression of BDE209 and DBDPE surface concentrations versus distance to known BFR manufacturing facilities fit the Gaussian Plume Dispersion model, and showed that, if the distance is shortened by half, concentrations of BDE209 and DBDPE would increase by 5-fold. The spatial distribution and temporal trend of the contamination indicate that the manufacturing of PBDEs and DBDPE is the primary source for these compounds in the environment of southern Arkansas. Interestingly, the occurrence of debromination of PBDEs in the sediments of a previously used wastewater sludge retention pond in Magnolia is indicated by the presence of congeners that had not been detected in any commercial PBDE mixtures and by increased fractions of lower brominated congeners relative to higher brominated congeners. Two unknown brominated compounds were detected in the sediments, and identified as nonabromodiphenyl ethanes.
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INTRODUCTION
Firemaster 2100 by Chemtura. Information on global consumption of DBDPE is not available. The U.S. EPA IUR record of DBDPE production volume is in the range of 10−50 million pounds for 2006.1 DBDPE has been detected in the air,3,4 tree bark,5 herring gulls eggs6 and sediments7 in the environment of North America. South-central Arkansas, with the largest natural bromine reserves in the country and the largest bromine production in the world,8 is home to major manufacturing facilities for BFRs in the U.S. Despite the strict measures in controlling and preventing discharges during the manufacturing process and voluntary actions to reduce emissions,9 unintended release of the products to the environment may not be avoidable. PBDEs
Decabromodiphenyl ether (BDE209) is the main component of the commercial polybrominated diphenyl ether (PBDE) product nicknamed “deca”, which has been marketed since the late 1970s. In the U.S., deca has been marketed under the trade names Saytex102E of Albemarle Corp. and DE-83R of Chemtura Corp. The aggregated U.S. national production volume of deca was in the range of 10−50 million pounds in 1986 and 1990, and 50−100 million pounds in 1994, 1998, 2002, and 2006, according to the U.S. EPA Inventory Update Reporting (IUR) data.1 Following the cessation of penta and octa production, Albemarle and Chemtura, as well as the largest U.S. importer, ICL Industrial Products, Inc., announced their commitments to phase out deca in the U.S. by December 31, 2012, and to end all its uses by the end of 2013.2 Decabromodiphenyl ethane (DBDPE) was introduced in the mid-1980s as a replacement for deca.3 It is marketed in the U.S. under the trade names Saytex8010 by Albemarle and © 2012 American Chemical Society
Received: Revised: Accepted: Published: 8017
March 29, 2012 July 11, 2012 July 13, 2012 July 13, 2012 dx.doi.org/10.1021/es301237w | Environ. Sci. Technol. 2012, 46, 8017−8024
Environmental Science & Technology
Article
Figure 1. Sampling locations. See Supporting Information SI-A1 for additional information.
diameter. At least four sediment cores were collected at each site. Individual cores were extruded with an hydraulic extruder and sliced into 0.5−5 cm sections immediately after sampling or early the next morning. The sections from the cores with the same sediment depth were combined into amber glass jars with Teflon-lined lids. A total of 149 samples were obtained and transported in iced coolers to the laboratory where they were kept frozen until analysis. Basic water quality parameters including temperature, pH, dissolved oxygen and conductivity were measured on site from the boat using hand-held meters. Sediment Characterization and Dating. The sediment samples were analyzed for water and solid contents, porosity, wet and bulk dry density, particle density, sediment organic carbon (OC) and black carbon (BC) using standard methods and methods previously established in our laboratory.16−18 Particle size distributions for all sediment samples were determined using the Mastersizer Hydro 2000 (Malvern Instruments, Worcestershire, UK).19 Samples collected at sites AED, AMW, and ACL were measured for selected radionuclides using gamma spectrometry with a Canberra model GR3020 reverse-electrode intrinsic Ge detector system interfaced with a DSA-2000 digital spectrum analyzer. Gamma activities were measured for 210Pb at 46.5 keV, 226 Ra at 186.2 keV, and 137Cs at 661.6 keV. Additional details are given in Supporting Information SI-C1. Both the constant initial concentration (CIC) and the constant rate of sedimentation (CRS) models20 were applied to the 210Pb data to estimate the mass sedimentation rates, which were then used to estimate the time of sediment deposition. The supported 210Pb activity level was reached when the activity ratio of 210Pb/226Ra approached unity. The peak of 137Cs activity was used to identify the year 1963, when the 137Cs release from nuclear weapons testing peaked, thus providing a cross-calibration point for 210Pb dating results. Chemical Analyses. Information on chemical purchases and detailed procedures of chemical analysis are described in Supporting Information SI-D1. Briefly, air-dried samples were mixed with anhydrous Na2SO4, spiked with the surrogates BDE30 and BDE190, and Soxhlet-extracted with 150 mL
and other brominated organics were detected in air particulates, soils, sediments and human hair in south-central Arkansas as early as 1978.10,11 According to the U.S. EPA Toxic Release Inventory (TRI),12 total U.S. industrial disposal or release of BDE209 in 2009 was 216 t, of which Arkansas accounted for 30%. PBDEs in tree bark collected within and around Arkansas were as high as 5700 ng/g lipid, in contrast to
