 Tobacco smoking is the most important single source of cadmium exposure in the general population . An estimated 10 % of the cadmium content of a cigarette is inhaled through smoking . Absorption of cadmium through the lungs is more effective than through the gut , and as much as 50 % of the cadmium inhaled in cigarette smoke may be absorbed . On average , cadmium concentrations in the blood of smokers is 4 times 5 times greater and in the kidney , 2 – 3 times greater than non @-@ smokers . Despite the high cadmium content in cigarette smoke , there seems to be little exposure to cadmium from passive smoking . 
