Introduction

Cadmium is widespread throughout the environment due to its industrial uses. Whether or not an individual sustains an unusual exposure depends on many factors such as level in the diet, route of exposure, smoking, age, gender, and other physiological factors.

Level and Duration of Exposure

The body burden of cadmium increases with age due to its minimal elimination from the body (0.001% of cadmium is excreted per day) and its subsequent long half-life of 38years. Especially high exposures can occur through jobs that involve possible exposures to cadmium as well as in certain hobbies such as jewelry making which can increase exposures.

Unusual Dietary Exposure

In the Jinzu River basin in Japan, environmental contamination of cadmium from manmade activities resulted in the uptake of this metal into the local rice crop. This uptake resulted in unusual levels of exposure to cadmium and the development of a severe form of cadmium poisoning in elderly post-menopausal females in that area, called “itai-itai” disease. The intake of rice accounted for 40% of the exposure suffered by the affected people. Middle-aged women in Japan were ingesting 37.5 μg/day of cadmium which was two to three times higher than other populations in southeast Asia. For comparison's sake, the average daily intake of cadmium is 6.3-27 μg/day in Europe, and 5-15 μg/day elsewhere in Asia (Tsukahara et al. 2003).

Smoking

The tobacco plant preferentially concentrates cadmium regardless of the amount of cadmium in the soil. The average cigarette contains 2 μg cadmium; 2-10% of that dose is transferred by primary cigarette smoke (Mannino et al. 2004). Of that, 10% to 50% of cadmium in cigarette smoke is absorbed by the lungs. Therefore, the average smoker has two times the amount of long term cadmium in their bodies than non-smokers (Satarug and Moore 2004; Waalkes 2003).

Effects on Cadmium Absorption

Cadmium absorption from the intestine increases when the body's iron stores are depleted. Cadmium absorption is also increased during pregnancy (Satarug and Moore 2004; Akesson et al. 2002).

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