What is the definition of aqueous for the purposes of determining whether a waste is corrosive?
There is no regulatory definition of aqueous however, for purposes of the corrosivity characteristic an aqueous waste is defined as the waste for which pH is measurable. Furthermore, Method 9040C in Test Methods for the Evaluation of Solid Waste, Physical/Chemical Methods (SW-846) is the appropriate test method to determine the pH of a waste. This method is used to measure the pH of aqueous wastes and those wastes where the aqueous phase constitutes at least 20% of the total volume of the waste. Therefore, any waste to which this method is applicable must contain at least 20% free water by volume.