Degradation studies database

The reaction databases let scientists easily and quickly retrieve information about the chemistry of known substances, some of which might be similar to the investigational compounds under study in forced degradation testing. Many of the readers of this book will already be acquainted with these informatics resources on their desktop computers. 

High confidence in an ora RfD can be achieved if the database is made up of at least one two-generation reproductive toxicity study, two chronic oral toxicity studies in two different species, and two developmental toxicity studies in different species. For compounds that pose only acute health hazards because low doses are degraded and/or excreted, chronic studies may not be as critical in deriving an RfD a.s special studies assessing specific end points, such as neurotoxicity (Ciemanee et ai, 1996). 

The SEHSC research efforts combined with those by the GSC resulted in the development of a comprehensive environmental database for PDMS, a material that has both industrial and consumer product applications. The results of this five-year research effort demonstrated that most PDMS used in down-the-drain applications enters the terrestrial environment as a component of wastewater treatment plant sludge, with aquatic sediments receiving between 3 to 6 % of this mass. Laboratory and field studies demonstrated the potential for PDMS degradation in soils and sediments. The rate of degradation is slow in sediment and wet soil and increases as a function of decreased moisture level to half-life values of days in dry soil. No adverse ecological effects are indicated from the effects testing. 

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