High-throughput Exposure and Risks Assessment of Chemicals in plastic Toys

A wide range of chemical additives is used during the manufacturing of plastic toys to obtain or increase specific properties in the final product. Hence, public concerns continue to rise about the possibility of plastic toys containing toxic
chemicals, which can pose risks to children’s health. Chemical substitution in combination with exposure and risk screening are useful tools to identify harmful chemicals in plastic toys and to evaluate alternatives. However, existing methods
lack efficient and flexible approaches to quantify exposure for the thousands of marketed chemical-plastic toy combinations. To address this gap, we propose a high-throughput framework for evaluating exposure to chemicals in plastic toys,
and test our framework in a case study on a wide range of organic chemical additives.We first quantify the chemical mass for hundreds of substances found in plastic toys. For each chemical-toy combination, we then calculate the fractions of
chemicals transferred to air and humans in a matrix approach. By matrix inversion, we estimate the Product Intake Fractions (PiF), relating the chemical mass taken in by children per unit mass of chemicals in toys. We finally determine
exposure doses expressed in mg/kgBW/d, Hazard Quotients (HQ) and Hazard Index (HI) for each chemical-toy combination. Based on these steps, we generate high-throughput exposure results for chemicals found in plastic toys.Considering
an average total mass of 18.3 kg plastic toys purchased yearly per child in western countries, the estimated exposure doses become substantial. Across 456 assessed chemical-toy combinations, the PiF ranges widely from a median of 0.2% to a maximum of 11% children intake per unit mass in toy. Resulting exposure doses for children vary from 0.015 to 10.5 mg/kgBW/d, dominated by dust ingestion and dermal gaseous uptake. Combining exposure estimates with toxicity data, we derive HQs and sum them to obtain HIs, which range widely and reach up to 1450 across chemical-toy combinations. Our results demonstrate that we are able to systematically identify main chemicals of concern in plastic toys and rank possible alternatives based on common chemical function. In addition, we are able to propose for each chemical-toy combination a hypothetical ‘safe’ threshold concentration. Our mass balance-based framework can be readily used in chemical substitution to screen a wide range of chemical-toy combinations, and can be extended to also assess other products.