Plasticizer migration from children's toys, child care articles, art materials, and school supplies☆
Introduction
Dialkyl ortho-phthalates, primarily diisononyl phthalate (DINP), have been used as plasticizers in children's products made from polyvinyl chloride (PVC), such as teethers and toys (Babich et al., 2004). Children may be exposed to plasticizers when handling or mouthing PVC products, because plasticizers are not bound covalently.
In the late 1990s, several laboratory methods were used to measure DINP migration from children's products made from PVC, to estimate mouthing exposure (reviewed in CHAP, 2001, CPSC, 2002). The methods generally involved extraction with saline or artificial saliva combined with some type of mechanical action, such as shaking (Axford et al., 1999; Earls et al. 1998, 2003; Rastogi et al., 1997; Steiner et al., 1998; Vikelsøe et al., 1997), ultrasound (Fiala et al., 2000; Steiner et al., 1998), impaction (Chen, 1998; HC, 1998), or tumbling (Rijk et al., 1999; Rijk and Ehlert, 1999; RIVM, 1998; Simoneau et al., 2001). The variety of methods led to a broad range of results (Table 1). The lack of a standard method, consistent units, and common test articles made it difficult to compare results using different methods. Eventually, a tumbling method developed at the TNO Nutrition and Food Research Institute (Rijk and Ehlert, 1999; RIVM, 1998) and subsequently modified by the European Commission Joint Research Centre (JRC) (Simoneau et al., 2001) emerged as a candidate standard method, and was evaluated in interlaboratory studies.
More importantly, the tumbling method compared favorably with results from human studies (reviewed in CHAP, 2001, CPSC, 2002). Groups of 10 adult volunteers were asked to mouth or gently chew PVC disks or teethers for a defined period of time, during which all saliva was collected, then analyzed to give a migraton rate (Rijk et al., 1999; Rijk and Ehlert, 1999). Using the TNO method, the mean in vitro migration rate was 1.5-fold greater than the in vivo migration rate using similar test articles. With the JRC method, the in vitro migration rate was 2.8-fold greater (Chen, 1998). There was considerable variation among individual adults (Chen, 1998; Rijk et al., 1999; Rijk and Ehlert, 1999). The migration rates by the JRC method roughly corresponded to the 95th percentile of the of the human volunteers (Simoneau et al., 2001). The JRC method has been referenced by other groups (EPA, 2017; Janssen and Bremmer, 2009; OECD, 2019).
The Consumer Product Safety Improvement Act of 2008 (CPSIA) permanently prohibited the sale of child care articles and children's toys containing more than 0.1 percent of di (2-ethylhexyl) phthalate (DEHP), butylbenzyl phthalate, or dibutyl phthalate. In addition, in 2018, the U.S. Consumer Product Safety Commission (CPSC) permanently prohibited the sale of child care articles and children's toys containing more than 0.1 percent of diisononyl phthalate (DINP), diisobutyl phthalate, di-n-pentyl phthalate, di-n-hexyl phthalate, and dicyclohexyl phthalate.
DINP has been the most common plasticizer in children's toys in the U.S. since DEHP was found to be an animal carcinogen (Babich, 2002; Babich et al., 2004). A voluntary standard prohibited the use of DEHP in teethers, rattles, and certain toys (TMA, 1986); the TMA standard was later incorporated into the ASTM F-963 toys standard. In the early 2000s, manufacturers began to replace phthalates with alternative plasticizers or replace PVC with plastics that do not require plasticizers (Babich, 2002; Babich et al., 2004). The CPSIA further limited the use of DINP and certain other phthalates in children's toys and child care products. Both the CPSC Chronic Hazard Advisory Panel on Diisononyl Phthalate (CHAP, 2001) and the CHAP on Phthalates and Phthalate Alternatives (CHAP, 2014; Lioy et al., 2015) recommended that federal agencies investigate the potential health risks of alternative plasticizers. Thus, CPSC staff has begun to evaluate exposure to alternative plasticizers and their potential health effects on children.
CPSC staff purchased soft plastic child care articles and children's toys in December 2008. The purpose of the study was to:
- 1.
Identify the plastic;
- 2.
Identify the plasticizer (when present) and measure the plasticizer concentration; and
- 3.
Measure plasticizer migration into a saliva stimulant to estimate oral exposure to a child mouthing the article.
The results of these studies may be used to estimate children's exposure to plasticizers from mouthing or handling PVC toys and child care articles (e.g., Babich et al., 2004; CHAP, 2014; Lioy et al., 2015).
Section snippets
Children's products
CPSC staff purchased 63 plastic children's toys and child care articles from local retailers in December 2008. The products comprised a total of 129 individual pieces (articles). Products included children's toys, child care articles, art materials, and school supplies (Table 2).
Chemical analyses
To identify plastics, all component parts of each sample were screened using a Thermo 6700 Fourier transform infrared (FTIR) spectrometer. The resultant IR spectrum was searched against a library to identify the type of
Identification of plastics and plasticizers
CPSC staff tested 63 plastic children's products comprising 129 individual pieces. The products tested included children's toys, child care articles, art materials, and school supplies (Table 2). Of the 129 articles, 30% (38) were made of PVC, followed by polypropylene (20% (26)), polyethylene (14% (18)), acrylonitrile butadiene styrene (ABS) (7% (9)), polystyrene (5% (7)), polyester (5% (7)), and other polymers (7.8% (10)) (Table 4). Eleven percent (14) of plastics were unidentified.
Composition of soft plastic toys
In the 1980s, most of the soft plastic toys sold in the U.S. were made of PVC and plasticized with DEHP (reviewed in Babich et al., 2004). DEHP was replaced by DINP after DEHP was shown to cause liver tumors in rodents (NTP, 1982). Thus, in 1998 DINP was present in about 90% of soft plastic toys that CPSC tested (Chen, 1998). Due to concerns about the toxicity of DINP, manufacturers began to remove phthalates from their toys, either by substituting with non-phthalate plasticizers or changing to
Funding information
There are no external funding sources for this work.
All work was performed by the authors, who are staff of the U.S. Consumer Product Safety Commission, during the course of their official duties.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors thank Celestine Kish, Michael Greene, and William Zamula for assistance in selecting test samples. We also appreciate the contributions of Warren Porter, Shing-Bong Chen, and Michael Greene to previous work on phthalates migration.
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Opinions expressed by the authors are those of the staff and do not necessarily represent the views of the U.S. Consumer Product Safety Commission. As the authors prepared this material in their official capacity, it is in the public domain and may be freely copied or reprinted.