Development of a Route of Exposure Model Using Silicone Wristbands as Personal Samplers

Project Summary Silicone wristbands (SWBs) are a relatively new personal sampling approach but have been increasingly used as personal passive samplers in over 25 publications representing over 1000 participants and 100s of detected chemicals in the short time they have been available. Using SWBs is appealing because they are easy to wear, have a wide range of potential capture, and do not require training, energy or maintenance. However, the effect and magnitude of skin/sweat/contact exposure versus air exposure when reporting chemical data from SWBs is not well understood. This application will help distinguish direct contact from atmospheric exposures and help predict dominant exposure routes for individual chemicals. Helping to predict chemical uptake and likely routes of exposure among multiple chemical classes will impact public health by dramatically increasing the efficiency of mitigating strategies, risk assessment and study of the exposome and how it impacts human health outcomes. Traditional methods of capturing personal exposures typically represents a single route of exposure and captures a specific chemical or set of chemicals. In contrast, silicone is a polymer well suited to capture a wide range of organic chemistry and SWBs can capture compounds dermally or through direct contact in addition to atmospheric sources. The resulting data from SWBs therefore represents a complex exposure profile that is often more relevant to internal dose for certain compounds. However, the additional capacity of wristbands absorbing chemicals from non-atmospheric sources is not yet easily characterized or predicted. Physicochemical parameters have been used previously to help predict atmospheric uptake for different chemicals. The proposed research will use SWB data and physicochemical parameters to build a prototype of a model that helps predict dominant routes of exposure. SWBs will be used in paired configurations (“traditional” and an “air-only” configuration) that will help compare routes of exposure and will be analyzed for over 1500 chemical compounds including pesticides, flame retardants, polycyclic aromatic hydrocarbons, phthalates, fragrances and additives in personal care products, food-related chemicals such as nicotine and caffeine, and chemicals associated with industry like plasticizers. There are two Aims to this proposal: 1) utilize multiple silicone wristband configurations in a field demonstration of atmospheric and contact absorption with a 1500 chemical screen among a maximum of 30 individuals, and 2) build a prototype of an uptake model that predicts dominant routes of exposure for chemicals based on their inherent characteristics. With two samplers for every participant, up to 60 samples will be screened for 1529 organic chemicals representing a rich dataset of personal exposures. This will serve as a good foundation to begin building robust exposure models.Project Narrative In the short term, this project will allow researchers to better interpret silicone wristband personal monitoring data by helping distinguish which chemicals came from air exposure and which from direct contact. If researchers more deeply understand silicone wristband data studies can be better targeted at less cost and complexity. In the long term, this research will help inform routes of exposure considerations in the exposome, and assist researchers, risk assessors, and even individual citizen-scientists in examining associations between chemical exposure and human health.