In a non @-@ smoking population , food is the greatest source of exposure . High quantities of cadmium can be found in crustaceans , mollusks , offal , and algae products . However , grains , vegetables , and starchy roots and tubers are consumed in much greater quantity in the US , and are the source of the greatest dietary exposure . Most plants bio @-@ accumulate metal toxins like Cd , and when composted to form organic fertilizers yield a product which can often contain high amounts ( e.g. , over 0 @.@ 5 mg ) of metal toxins for every kilo of fertilizer . Fertilizers made from animal dung ( e.g. , cow dung ) or urban waste can contain similar amounts of Cd . The Cd added to the soil from fertilizers ( rock phosphates or organic fertilizers ) become bio @-@ available and toxic only if the soil pH is low ( i.e. , acidic soils ) . Zinc is chemically similar to cadmium and some evidence indicate the presence of Zn ions reduce cadmium toxicity .