Table 2.

Percentage of kidney samples with higher heavy metal concentration than normal. Mean ± SD.

Heavy metal	Content in kidney tissue (mg/kg)	Normal levels in human kidney (mg/kg)	Percentage of samples above normal
Cu	8.8 ± 4.4	0.70–10.3 [20]	25.5
Pb	3.6 ± 1.5	0.02–0.90 [21]	97.9
Cd	13.2 ± 16.6	0.50–120 [22]	0