Developing Quantum Chemical and Polyparameter Models for Predicting Environmentally Significant Parameters for New Munition Compounds
ER-1734
Objective
Evaluating the environmental impact of new munitions requires that estimates be made of their physical chemical properties and, more important, the parameters that determine their fate in the environment. This approach is not new to the science of environmental assessment. The Toxic Substance Control Act started this approach with the development of quantitative structure activity relationships. However, the available methods are not reliable for chemical classes outside their training set. In particular, chemicals with nitro- group functionality have large prediction errors using the conventional methods.
The objective of this project is to develop models for predicting the physical chemical properties (aqueous solubility, octanol-water partition coefficient, and Henry’s Law constant) and the potential bioaccumulation and metabolism of new munition compounds partitioning into soil organisms and plants. This requires a new generation of models that rely on quantum chemical (QC) methods to estimate the physical chemical properties and the necessary model partition coefficients and metabolism parameters.
Technical Approach
The project team previously tested the predictive ability of QC methods (COSMO-SAC and SM5) as well as other commonly used estimation methods applied to munition chemicals, and the QC methods were clearly superior. In this project, researchers will combine these estimation methods to produce optimal estimates using a technique successfully applied to estimating atomization enthalpy using the estimates from multiple functionals in QC density functional theory. The framework and data exist for building the next generation of models for predicting bioconcentration factors (BCFs) and metabolism. The aim is to build a model that predicts BCFs in the absence of metabolism. The reliance on octanol/water partition coefficient that severely limits the applicability of present day models will be replaced with QC-based estimates of partition coefficients and other parameters. Researchers will develop new BCF data for a soil invertebrate and a plant using munition and analog chemicals to validate that the new models can make predictions for this class of chemicals.
Benefits
The new physical chemical, BCF, and metabolism models based on QC models will enable risk assessments to be made on new munitions compounds in the early stages of their development. This will provide an early warning of potential environmental problems that can be investigated in a timely fashion. The costly and time-consuming effort to experimentally determine these parameters can be employed for only those compounds that are estimated to pose little risk. Scientifically sound risk assessments support the sustainable use of operational ranges. (Anticipated Project Completion - 2013)
Points of Contact
Principal Investigator
Dr. Dominic Di Toro
University of Delaware
Phone: 302-831-4092
Fax: 302-831-3640
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.