Q: Where can I find information about how SRD estimates the ranking of products?
A: The model documentation is contained in the help screens within the model and in greater detail in the following two documents: Source Ranking Database, Volume 1: Guide and Documentation, Oct. 2003 and Source Ranking Database, Volume 2: Appendices, April 2003.
Q: Has the SRD been peer reviewed?
A: The SRD was reviewed by EPA’s Science Advisory Board (SAB) in July 1997. The SAB’s final report, http://www.epa.gov/sab/pdf/ihec9804.pdf, contained recommendations for a variety of changes and improvements to the SRD. The primary comments from the SAB review related to the algorithm used to rank products. In particular, the SAB Committee recommended that the algorithm be reviewed and that attention be paid to several issues such as the overall sensitivity of the algorithm to variability in the component factors and in the hazard scale. In addition, several additional recommendations were made including: a) addition of additional exposure sources to SRD; b) addition of octanol/water partition coefficient and Henry’s Law ratio so that sorption/desorption and volatilization processes can be better addressed; and c) consideration of the need for regular updates and accessibility of the database to the public.
Q: What types of formulation data were used in the SRD? How robust are the data sets in the SRD?
A: Much of the information in the Source Ranking Database is from secondary sources and has generally not been verified against primary sources. The formulations data sets are generally pre-1990 or are based on published formulary text books (e.g, Advanced Cleaning Product Formulations by Ernest W. Flick). Additionally, many values (i.e., time used, amount used, indoor environment product used in, etc.) needed for the exposure calculations are based upon professional judgment because of the lack of relevant data. The hazard scores are used for screening only and do not represent official indication of hazard for chemicals.
A: No. The Source Ranking Database is a tool for developing risk-based rankings of products and product categories, but does not provide actual risk assessment conclusions on products or chemicals.