Article pubs.acs.org/est
Contamination by Ten Harmful Elements in Toys and Children’s Jewelry Bought on the North American Market Mert Guney and Gerald J. Zagury* Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, Montréal, Québec, H3C 3A7, Canada ABSTRACT: Toys and children’s jewelry may contain metals to which children can be orally exposed. The objectives of this research were (1) to determine total concentrations (TC’s) of As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sb, and Se in toys and jewelry (n = 72) bought on the North American market and compare TC’s to regulatory limits, and (2) to estimate oral metal bioavailability in selected items (n = 4) via bioaccessibility testing. For metallic toys and children’s jewelry (n = 24) 20 items had TC’s exceeding migratable concentration limits (European Union). Seven of seventeen jewelry items did not comply with TC limits in U.S. and Canadian regulations. Samples included articles with very high Cd (37% [w/w]), Pb (65%), and Cu (71%) concentrations. For plastic toys (n = 18), toys with paint or coating (n = 12), and brittle or pliable toys (n = 18), TC’s were below the EU migration limits (except in one toy for each category). Bioaccessibility tests showed that a tested jewelry item strongly leached Pb (gastric: 698 μg, intestinal: 705 μg) and some Cd (1.38 and 1.42 μg). Especially in metallic toys and jewelry, contamination by Pb and Cd, and to a lesser extent by Cu, Ni, As, and Sb, still poses an acute problem in North America.
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INTRODUCTION Children are particularly sensitive to metal exposure due to their physiological and developmental properties, and they are already exposed to certain levels of metals via multiple pathways, i.e., food, air, water, and soil.1−4 Especially for children younger than 6 years old, mouthing of objects is an important behavior where mouthing frequency and times vary according to age category.5−8 Release of metals from contaminated toys or children’s jewelry via mouthing or ingestion of contaminated matrix is possible; therefore, this exposure pathway may add to the present carcinogenic and noncarcinogenic risks for children caused by elemental exposure. Toys and jewelry may contain high levels of metals due to several factors, i.e., use of metals as stabilizers in plastics, application of paint containing metal pigments, and use of contaminated recycled plastics or toxic metals in production. Lack of regulations for certain contaminants and problems in enforcement of regulations are the main reasons for the presence of contaminated toys and jewelry in the market.9−11 In 2007 and 2008 alone, more than 100 recalls of children’s products were issued in North America, including the ones comprising millions of items that have been made in the past decade in North America because of chemical safety hazards.12−14 Also, in the past, children’s exposure to Pb via ingestion of low-cost jewelry resulted in cases of serious acute or chronic adverse effects, including death.15−17 The sources and toxic effects of various contaminants in toys and children’s jewelry have been previously discussed in detail, and the presence and leaching potential of metals were reported in the recent reviews of Becker et al. and Guney and Zagury.9,11 © XXXX American Chemical Society
Metals may be released from toy and jewelry matrices in gastric and intestinal fluids following partial ingestion (i.e., scraped coatings, fibers, textile, broken sections) or whole ingestion (small jewelry items, detachable pieces). Hence, significant amounts of metals may become bioavailable and harm various organs once having reached systemic circulation. Oral bioavailability is the fraction of a contaminant reaching the systemic circulation from the gastrointestinal tract after ingestion, and oral bioaccessibility is the fraction of the substance that becomes soluble in the gastrointestinal tract and is thus available for absorption.18 Bioaccessibility can be used as an estimation of bioavailability and, when available, validated in vitro bioaccessibility tests might be preferred over in vivo bioavailability tests for their cost advantages and ethical considerations regarding in vivo testing. A limited number of studies have investigated the bioaccessibility of metals in toys, concentrating mainly on jewelry and solely on Pb or Cd bioaccessibility. Yost et al.19 used a test proposed by U.S. CPSC to determine accessible Pb in contaminated plastic jewelry (test conducted in 0.07 M HCl without digestive enzymes or an intestinal phase). Total accessible Pb measured in 9 items was between 7.5 and 1290 μg per item. Weidenhamer et al.20 recently investigated bioaccessibility of Cd in contaminated jewelry using saline and diluted HCl solutions (representing mouthing and ingestion, respectively). Received: December 5, 2012 Revised: April 18, 2013 Accepted: April 26, 2013
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dx.doi.org/10.1021/es304969n | Environ. Sci. Technol. XXXX, XXX, XXX−XXX
Environmental Science & Technology
Article
which may be subject to exposure was sampled and acid digested. One composite sample was prepared for toys when found necessary by crushing and mixing parts with different colors from the same toy. Additional subsamples (different parts or sections) were analyzed for MJ24 (2 subsamples) and PL05 (7 subsamples). In particular, for the MJ category, the entire item was tested for 10 samples (MJ01, 02, 03, 04, 05, 06, 11, 12, 13, and 30) while an intact part of an item (i.e., pendant from a jewelry) was used for the remaining 14 articles (see Table 1 for sample details). In summary, a total of 24 toys and children’s jewelry from MJ, 18 toys from PL, 12 toys from PC, and 18 toys from BP have been analyzed for their elemental content (detailed descriptions of items given in Tables 1−4). The digestions were performed according to the Standard Method 3030 (via HNO3 digestion on a hot plate, followed by optional additional digestion via HClO4 or HClO4/HF when necessary).29 All analyses were made in duplicate (with the exception of samples PC01−19, BP27, and BP28 due to the limited amount of toy material available). Digestates and procedure blanks were filtered (45 μm), diluted to 50 mL, and preserved at 4 °C until analysis. As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sb, and Se concentrations in the digestates were measured by ICP-OES (method detection limits (in μg·L−1); As: 19.5, Ba: 0.12, Cd: 1.2, Cr: 1.8, Cu: 2.4, Mn: 0.24, Ni: 5.7, Pb: 16.6, Sb: 15.6, and Se: 34.3). The concentrations of elements in toy/ jewelry material were expressed in mg.kg−1. Determination of Bioaccessibility. Selected samples (MJ14, PL05/1, BP04, and BP11, n = 4), based on total metal content and toy/jewelry category, were submitted to the IVG bioaccessibility protocol.30 The IVG protocol is a physiologically based test that mimics gastrointestinal conditions at 37 °C with the presence of NaCl, pepsin, bile, and pancreatin under controlled pH (with HCl) . It has been widely used in the assessment of metal bioaccessibility in soils31−34 and validated against in vivo studies to assess As, Cd, and Pb bioaccessibility for some soils.30,35,36 Bioaccessibility tests were made in triplicate and two procedure blanks were processed. The gastric phase of IVG was conducted for 1 h at a pH of 1.8 followed by the intestinal phase for 1 h at a pH of 5.5. A sample amount around 1 g was tested. Ten milliliters of sample was taken from each triplicate and from the procedure blank at the end of gastric and intestinal phases. After centrifugation (5000g) and filtration (45 μm), 1 mL of HNO3 was added to the samples. The samples were then preserved at 4 °C until analysis. The concentrations of As, Ba, Cd, Cu, Pb, and Sb (elements with significant concentrations in selected items) were measured by ICP-OES. From liquid concentrations, migrated amounts of elements (in μg, = elemental concentration × volume of gastric or intestinal liquid) and migratable concentrations of metals in toy/jewelry material (mg.kg−1, = migrated amount/sample mass) were calculated (Table 5). Quality Assurance, Quality Control. To assess accuracy of the digestion protocol, one standard reference material (SRM54d, tin-base bearing metal) was analyzed in duplicate. The reference values (%w/w) were 7.04 for Sb, 3.62 for Cu, 0.62 for Pb, and 0.002 for Ni. The results obtained were consistent with the certified values (%w/w, 8.98 for Sb, 3.50 for Cu, 0.65 for Pb, and 0.004 for Ni; within 20% of certified values for Sb, Cu, and Pb). In order to assess the reproducibility of the IVG protocol, As bioaccessibility in one standard reference material (SRM2710, Montana highly elevated trace element concentration soil) was determined in triplicate. Intestinal bioaccessibility of As was 29.2% (relative standard deviation
They found that Cd can leach to saline and, to a larger extent, to HCl solution. Brandon et al.21 investigated bioaccessibility of different contaminants in consumer products by using a detailed physiologically based in vitro digestion model. This study included a few toy samples (one finger paint and one chalk spiked with Pb, and one chalk contaminated by Pb), and only Pb bioaccessibility was investigated (reported as
