The TCLP and SPLP were conducted according to U.S.
EPA method 1311 and 1312, respectively. To increase the
number of samples that could be processed at one time, the
procedures were modified by reducing the sample mass to
2 g. The sample was placed into a 50-mL polyethylene centrifuge tube (Fisher Scientific, Waltham, MA, USA; Cat. No. 06-
443-20), to which 40 mL of extraction fluid no. 1 (