Description
Six of the metals (Cd, Cr, Co, Mn, Ni, and Pb) found to be present in low to moderate concentrations were identified as Hazardous Air Pollutants (HAPs) in the 1990 Clean Air Act Amendments (CAAA) USA. The concentration of Fe, Mg and Al was observed to be higher than the rest of the metals. Significant variation of these metal contents in the four coals samples was observed with no noteworthy statistical relationship with the ash and carbon contents of the coals. The concentrations of metals in the samples are within the average world coal range. It was also observed that there is no definite trend of metal concentration with reference to different collieries of Assam. The association of some metals in the coal matrix was also discussed. XRD and FT-IR patterns of the coals also supported the presence of these metals.
