Assessing Human Exposure to SVOCs in Materials, Products, and Articles: A Modular Mechanistic Framework

Abstract

A critical review of the current state of knowledge of chemical emissions from indoor sources, partitioning among indoor compartments, and the ensuing indoor exposure leads to a proposal for a modular mechanistic framework for predicting human exposure to semivolatile organic compounds (SVOCs). Mechanistically consistent source emission categories include solid, soft, frequent contact, applied, sprayed, and high temperature sources. Environmental compartments are the gas phase, airborne particles, settled dust, indoor surfaces, and clothing. Identified research needs are the development of dynamic emission models for several of the source emission categories and of estimation strategies for critical model parameters. The modular structure of the framework facilitates subsequent inclusion of new knowledge, other chemical classes of indoor pollutants, and additional mechanistic processes relevant to human exposure indoors. The framework may serve as the foundation for developing an open-source community model to better support collaborative research and improve access for application by stakeholders. Combining exposure estimates derived using this framework with toxicity data for different end points and toxicokinetic mechanisms will accelerate chemical risk prioritization, advance effective chemical management decisions, and protect public health.

Mining of Consumer Product Ingredient and Purchasing Data to Identify Potential Chemical Coexposures

“…Additionally, only chemicals in formulated products and not consumer articles (such as building materials and furnishings) are considered here. Articles contain and emit chemicals (including potential EACs such as phthalates) into the residential environment (Eichler et al 2021) and thus likely affect coexposures. New technologies in the areas of analytical chemistry, such as nontargeted analysis (NTA), can help identify many chemical ingredients in products, including those in formulated products that were not added intentionally (e.g., residues from manufacturing processes) and those in articles.…”

Addressing the importance of microplastic particles as vectors for long-range transport of chemical contaminants: perspective in relation to prioritizing research and regulatory actions

“…can be on the order of several decades [99], which can result in concerns regarding the continuous leaching of PACs from widely used consumer products. Over the last several years considerable research aimed at reporting both estimated and measured emission rates for characterizing and quantifying human exposure due to oral ingestion, inhalation and dermal uptake have improved our understanding of environmental emissions [111][112][113][114][115][116][117]. Emissions of PACs from consumer products in indoor environments, industrial activities such as shipping and agriculture, and other human-related activities all represent potentially important sources to the environment (Fig.…”

“…Emissions of PACs from consumer products in indoor environments, industrial activities such as shipping and agriculture, and other human-related activities all represent potentially important sources to the environment (Fig. 2) [112].…”

“…When considering the summary illustrated in Fig. 2, with respect to the variable emission sources of PACs to the environment, it is important to appreciate that estimates of environmental emissions require the development and application of mechanistically consistent source emission categories, which can be used towards strengthening the reliability of models aimed at evaluating the environmental fate and transport of PACs via different emission pathways and exposure scenarios [112]. It is well understood that the emission of PACs from a specific in-use plastic product will be strongly influenced by a chemical's physicochemical properties, the properties of the plastic article and the environmental properties, such as temperature.…”

“…Depending on the environmental properties where the in-use plastic product is used, such as air flow rates, the composition and volume fraction of other particles and dust, as well as the properties of other infrastructure, such as indoor surfaces, the surrounding environment can play an important role influencing the fate of PACs released from the product. Because the direction of flux associated with the emission of PACs from products is dependent on the properties of the chemical and the direction of the chemical fugacity gradient, the relative importance of a specific product as a source or sink for PACs can be determined [112]. Estimates of indoor concentrations of PACs, for instance, have been derived through the application of multimedia environmental fate models [112].…”