Each sample was air-dried at ambient temperature, disaggregated, and sieved to <2 millimeters (mm). The <2-mm material was then crushed to <150 micrometers (µm) prior to chemical analysis. Mercury (Hg) was determined by cold-vapor atomic absorption spectrometry after dissolution in a mixture of nitric and hydrochloric acids in a modification of the method published by the U.S. Environmental Protection Agency (1994).

U.S. Environmental Protection Agency, 1994, Method 7471B (revision 2)--Mercury in solid or semisolid waste (manual cold-vapor technique), in Inorganic analytes, chap. 3 of Test methods for evaluating solid wastes, physical/chemical methods: U.S. Environmental Protection Agency SW-846, 11 p.