Table 2.

The Heavy Metal (Cr, Pb & Cd) Content in Different Categories of Tannery Wastes and Feeds

Sample Group	Sample Category	Cr Conc. (mg/kg)	Pb Conc. (mg/kg)	Cd Conc. (mg/kg)
Group A* Solid tannery waste	Raw Skin	2.52	8.06	BDL**
	De-haired skin	0.12	BDL	BDL
	Raw skin after tanning	3.89	BDL	BDL
	Unprocessed leather	3.54	BDL	BDL
	Shaving dust	3.44	13.0	BDL
	Shaving dust (treated)	2.97	BDL	BDL
	Shaving dust (boiled)	2.34	BDL	BDL
	Shaving dust (boiled & dried)	2.49	BDL	BDL
	Shaving dust powder (colorless)	2.89	15.0	BDL
	Shaving dust powder (colored)	3.11	22.0	BDL
Group C* Protein concentrate	Protein concentrate (open)	0.66	10.2	BDL
	Protein concentrate (local)	0.23	BDL	BDL
	Protein concentrate (multi)	0.22	BDL	BDL
	Protein concentrate (foreign)	0.12	BDL	BDL
Group D* Feed	Feed for broiler poultry	0.98	10.32	0.03
	Feed for Deshi poultry	0.28	10.27	BDL
	Feed for both types of poultry	0.27	10.36	0.05

^*Mean value of 3 samples in each category, n=3

^**ND=Not done; BDL=below detection limit, detection limit of each heavy metal is given in Table 2