Article pubs.acs.org/est
Human Dietary Exposure to PBDEs Around E‑Waste Recycling Sites in Eastern China Iryna Labunska,*,† Stuart Harrad,‡ Mengjiao Wang,† David Santillo,† and Paul Johnston† †
Greenpeace Research Laboratories Innovation Centre Phase 2, Rennes Drive University of Exeter, Exeter, EX4 4RN United Kingdom ‡ School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT United Kingdom S Supporting Information *
ABSTRACT: Analysis of 10 types of locally produced staple foods (including meat, fish, and eggs), provided estimates of dietary intakes of polybrominated diphenyl ethers (PBDEs) for residents of areas of Taizhou City (Zhejiang Province, Eastern China), which are long-established centers of rudimentary “ewaste” recycling. Average ∑PBDE concentrations in chicken meat, eggs, and liver and duck meat and liver were among the highest recorded to date, with BDE-209 particularly abundant. The highest estimated contributions to ∑PBDE intake under a median exposure scenario were associated with adult consumption of duck eggs (3882 ng/day) and chicken eggs (1091 ng/day), and with consumption of fish by both adults (792 ng/ day) and children (634 ng/day). Including estimates for ingestion of contaminated dust reported elsewhere increased median ∑PBDE daily intakes by approximately 19% for adults and 42% for children. Normalized to body weight, estimated median ∑PBDE exposures (from food and dust combined) were 130.9 ng/kg bw/day for adults and 614.1 ng/kg bw/day for children. High-end estimates of exposure for young children exceeded the U.S. Environmental Protection Agency reference doses for BDE-47 and BDE-99 by factors of approximately 2.5 and 1.5, respectively.
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imports were banned formally in 2000,5 a recent report6 notes that in 2012, domestic sources in China overtook the U.S. as a source of e-waste. Primitive methods are often employed in ewaste recycling operations in China, resulting in extensive releases of toxic substances to local environments that can result in severe pollution problems.7−11 Some contaminants released, including PBDEs, can subsequently be accumulated through food chains, rendering diet a potentially important human exposure pathway for PBDEs in e-waste recycling areas.12 Taizhou City in Zhejing Province (Eastern China) has reportedly been involved in e-waste operations for nearly 30 years and is one of the largest centers for such activities in China. A number of different operations employing rudimentary methods for recovery or disposal of wastes have been reported in this region, including unprotected manual dismantling, open burning, acid treatment to recover metals, and unregulated disposal.13,14 However, despite substantial data about environmental contamination by PBDEs in China as a result of e-waste recycling, human dietary exposure to PBDEs
INTRODUCTION Polybrominated diphenyl ethers (PBDEs) are a group of chemicals used widely as flame retardants in a variety of commercial products, including electrical and electronic equipment (EEE). However, due to growing recognition of their toxicity, high environmental persistence, and potential to bioaccumulate, many PBDE formulations have come under increasing regulatory control. For example, hexa- and heptaBDEs (key congeners in commercial octa-BDE mixtures) as well as penta- and tetra-BDEs (key congeners in commercial penta-BDE mixtures) have been listed under Annex A of the UNEP Stockholm Convention for elimination as persistent organic pollutants (POPs).1,2 Additionally, new production of penta- and octa-BDE has been banned in the EU since 2003,3 and in several other jurisdictions. Commercial deca-BDE mixtures, comprised mainly of BDE-209 are also undergoing consideration for listing under the Stockholm Convention. Use of deca-BDE (with other PBDEs) in EEE has already been restricted within the EU under the ROHS directive.4 However, despite these restrictions, PBDEs are still released into the environment from products containing them, during use and during disposal or recycling of electrical and electronic wastes (e-wastes) at the end of the products’ useful life. China is a major processor of e-waste, with both imported and domestic waste being important sources. Although e-waste © 2014 American Chemical Society
Received: Revised: Accepted: Published: 5555
January 16, 2014 April 11, 2014 April 15, 2014 April 15, 2014 dx.doi.org/10.1021/es500241m | Environ. Sci. Technol. 2014, 48, 5555−5564
Environmental Science & Technology
Article
from analysis. Chicken eggs were prepared as described previously for duck eggs.25 In summary, yolks were separated from whites and thoroughly homogenized with a spatula. Homogenized yolk (0.2 g) was spiked with internal (or surrogate) standards F-BDE-69, F-BDE-160, and 13C-BDE-209, mixed with Hydromatrix and sodium sulfate and transferred into a precleaned “Dionium” accelerated solvent extraction (ASE) cell. The lower section of the cells was packed with layers of sorbents (to facilitate in-cell extract cleanup), including acidified silica (10 g), florisil (4 g), silica (2 g), and neutralizing agent CR Na+ (Dionex) (5 g). Samples were extracted into pentane using an ASE 350 (Dionex) system. Following extraction, 20 μL toluene was added as a keeper solvent, before extracts were evaporated to incipient dryness under nitrogen and reconstituted immediately with 50 μL toluene containing 2.5 ng of PCB-209 as a recovery determination (or syringe) standard (RDS). Analysis was performed using GC/ECNI-MS (see below). A similar procedure was applied for extraction of other food types, only larger sample masses were analyzed (0.5 g for freeze-dried samples) and a correspondingly increased quantity of acidified silica (20 g) employed to facilitate extract clean up. Sample lipid content was determined on a separate subsample to that used for PBDE analysis, as described in SI. GC/MS Analysis. Analysis was performed using an Agilent 6890 Series gas chromatograph fitted with a Restek Rtx-1614 column (15 m, 0.25 mm ID, 0.1 μm film thickness) interfaced with an Agilent 5973 MSD, using electron capture negative ionization (ECNI) in the selected ion monitoring (SIM) mode and methane as reagent gas. All GC/MS parameters were as described previously.25 Quantification was carried out via the internal standard method, using F-BDE-69 as an internal (surrogate) standard for tri- to penta-BDEs, F-BDE-160 for hexa- to nona-BDEs, and 13 C-BDE-209 for BDE-209. Native and 13C-labeled PBDEs were obtained from Wellington Laboratories (Canada), and fluorinated BDEs from Chiron AS (Norway). Six-point calibrations were prepared and relative response factors (RRFs) calculated for each target PBDE. Relative standard deviations (RSD) for calculated RRFs ranged from 1.5 to 7.0%. QA/QC. To evaluate method accuracy and reproducibility, five samples of certified reference material NIST SRM2974A “Organics in freeze-dried mussel tissue (Mytilus edulis)” were analyzed. Concentrations agreed well with certified values, with satisfactory reproducibility illustrated by the standard deviation (Figure S2 in SI). Procedural blanks were run after each five samples and contained
