Corrigendum to ‘From e-waste to living space: Flame retardants contaminating household items add to concern about plastic recycling’

The authors regret that the formula used to estimate BDE-209 exposure from contaminated kitchen utensils to hot cooking oil, based on the simulated cooking experiments of Kuang et al. (2018) and the median levels found in the contaminated cooking utensils, was misinterpreted. This misinterpretation led to an overestimation of the BDE-209 exposure concentration. The corrected estimated BDE-209 exposure is 7900 ng/day instead of 34,700 ng/day. Kuang et al. (2018) noted that their formula to estimate daily exposure to brominated flame retardants (BFRs) was based on multiple assumptions. In their study, the grips of the kitchen utensils, which had some of the highest BDE-209 levels, were included in determining the BDE-209 transfer rate (11.7 %). We followed the Kuang et al. approach, basing the exposure estimate on four kitchen utensil grips (S5, S7, S9, S10) with detections of BDE-209. In the corrected calculation, four of the nine kitchen utensils analyzed were included, to provide a worst-case scenario of exposure in the case of cooking with a contaminated kitchen utensil. The two peelers, with no anticipated contact with hot oil, contaminated with BDE-209, and the three utensils (S4, S6; grip, S8; grip) with BDE-209 levels below the limit of quantification (LOQ) were excluded from the calculation. The calculation of the estimated BDE-209 exposure is given below. The formula used by Kuang et al. (2018) to assess the daily brominated flame retardant (BFR) exposure (E_BFR—oil) from hot cooking oil is: [Formula presented] ● C_{BFR—utensil}: BFR concentration (ng/g) in kitchen utensils● r_exp: BFR transfer rate from kitchen utensils to cooking oilThe estimated exposure was calculated using the transfer rate for BDE-209 (r_exp = 11.7 %, Kuang et al., 2018) and the median BDE-209 level (ng/g) in the contaminated kitchen utensils (see table below). [Formula presented] The estimated BDE-209 intake from the contaminated kitchen utensils to the cooking oil = 0.27 * 250,000 * 0.117 = 7897.5 ng/day. Rounding to three significant digits, the corrected estimated BDE-209 exposure is 7900 ng/day. As with all exposure estimates, there are uncertainties that must be taken into consideration. We applied the experimentally-derived transfer rate and estimation method from Kuang et al. as it provided the only relevant peer-reviewed data we were aware of. This estimate was provided to contextualize potential exposure to a single FR detected in one product category through cooking, but the exposure estimate and its comparison to the reference dose have limitations. For example, it is unknown to what extent the experiments overestimate or underestimate leaching during actual cooking, how often a specific utensil would be used, and whether the grips may or may not come into contact with hot oil. In addition, the U.S. EPA (1993) makes clear that published reference doses should be considered as reference points for considering the potential effects of a chemical, not as a level determining what an “acceptable” or “unacceptable” exposure would be. We regret not including a full discussion of the limitations in the exposure discussion. Importantly, the core findings and conclusions of the study remain unchanged: toxic flame retardants used in plastics can significantly contaminate products made from recycled materials, even when flame retardancy is not required. The study was not designed to determine whether black plastic posed an unacceptable exposure but rather “to determine whether black plastic household products sold on the U.S. market contained emerging and phased-out flame retardants (FRs) and whether polymer type was predictive of contamination,” as stated in the manuscript. As is typical in investigations of products that may contain recycled content, we conducted an XRF screening step to focus analytical efforts on the 20 products (out of 203) most likely to contain BFRs, as stated in the paper. The measurements of the FRs in the samples were performed by Vrije Universiteit, without specific information about the components of the products that were analyzed. The study focused on assessing the presence of toxic flame retardants in black plastic household items. As stated in the conclusion, it is clear that more regulation is needed. Needed changes include requiring disclosure of content of intentionally added chemicals and contaminants, restricting the intentional use of toxic FRs in products, prohibiting hazardous chemicals in recycled content, and moving manufacturers to the safest materials and chemicals. The authors sincerely apologize for any confusion or inconvenience caused.