Concerns about cadmium

Concerns about cadmium have been triggered by uncertainties about this heavy metal impacting human health and creating environmental risks.

The exposure of humans to cadmium is largely driven by the uptake of cadmium by staple food crops, which absorb the metal from the soil. Cadmium occurs in all food, but agricultural crops (particularly irrigated rice) generally account for most of the intake.

Health impacts

Cadmium is a non-essential and toxic element for humans mainly affecting kidneys and the skeleton. It is also a carcinogen by inhalation. Cadmium is accumulated in bone and may serve as a source of exposure later in life.

The risk of cadmium on health is increased on populations with deficiencies in calcium, zinc, and iron. Populations in developing countries, where such deficiencies are prevalent, would thus be most at risk, and more particularly women of child-bearing age who are iron-depleted and anemic.

Environmental impacts

Cadmium is toxic to plants, animals and micro-organisms. Being an element, cadmium is persistent – it cannot be broken down into less toxic substances in the environment.

The degree of bioavailability and potential for effects varies depending on the form of cadmium and the soil pH. Cadmium bioaccumulates mainly in the kidneys and liver of vertebrates and in aquatic invertebrates and algae.
These concerns are not new, but knowledge of the relative importance of the various pathways for human exposure is changing following the establishment of regulations (such as against nickel batteries).