EAGER: A Process Systems Engineering Approach to the Characterization of Persistence in Chemodynamic Patterns as an Exposure-Based Hazard and Chemical Process Safety Indicator

Worcester Polytechnic Institute, Worcester MA

Investigators

Abstract

1008158 Kazantzis This project focuses on the design and implementation of a comprehensive regulatory regime for the management of chemicals which represents a critical component of chemical process safety. In these regulatory structures, the need to use appropriately validated models that: i) faithfully describe the fate of chemicals released into the environment ("chemodynamics"), and ii) provide the means to assess through properly defined indices exposure levels of populations and ecosystems is needed. These models are realized through mass balances in different environmental media (air, soil, water, etc) reflecting the fact that the behavior of a chemical is jointly determined by the inherent physicochemical properties and underlying environmental processes such as degradation in and partitioning between media, etc. Traditionally, the management of chemicals has been based on risk criteria related solely to the inherent physicochemical properties, ignoring the complexities associated with the above processes and unnecessarily resulting in misclassification of their risk. In light of the above considerations, process systems engineering principles can be useful not only in the development and analysis of chemodynamic models in the presence of inherent nonlinearities/complexity, but also in introducing a comprehensive set of indices through which exposure hazard assessment becomes feasible when a large number of chemicals need to be prioritized on the basis of risk. In particular, this research aims at developing a new set of appropriately defined indices for the characterization of persistence of chemicals after their release into a multimedia environment, since persistence figures prominently as a key exposure-based indicator within contemporary frameworks of chemical risk assessment. Effectively overcoming limitations associated with traditional approaches that could lead to a misclassification of chemical substances on the basis of their persistence potential, this set of persistence indices will retain a computational approach while using certain measures/indices for the characteristic time found in dynamic systems theory. These exposure indices will capture the full dynamic history of the chemical's environmental behavior without requiring detailed knowledge of the particular release pattern, circumventing the standardization difficulties encountered when a large number of chemicals need to be screened. Furthermore, the persistence indices will be calculated on the basis of validated multimedia chemodynamic models for classes of chemicals of particular interest to the chemical industry, as new sets of data will be generated in response to recent international regulatory regimes. The pertinent body of knowledge is at a rather nascent state, which inevitably introduces an element of uncertainty on the outcome of the research program. Intellectual Merit: The intellectual merit lies in the development of a new comprehensive interdisciplinary methodological framework that would enable the synergistic integration of process systems engineering principles and methods with chemical risk assessment, management and process safety. Broader Impact: This framework is expected to have a direct impact on the scientific foundations of emerging regulatory regimes for the management of chemicals designed to protect public health and ecosystem functions, as well as on environmental health and safety practices followed in the chemical industry. Educational objectives would also complement the above research plan and become centered around the experience of the first intellectually critical years of the doctoral education of a female graduate student who would be interested in contributing to the advancement of knowledge in an emerging interdisciplinary field of scientific inquiry.