Cadmium
Accumulation in Soybeans
What were the goals of this study?
- Identify soil variables
that can predict the concentration of cadmium in soybeans
- Determine how
accurately these soil variables can predict cadmium concentration in soybeans.
Why
is this study important?
- Soy-based food consumption is increasing
- Within
healthy populations, cadmium in soy is of greatest concern for women and children
- Total
Diet Health Study (Health Canada) reports that soy-based infant formula contains
2X the cadmium found in milk-based infant formula.
What did we
find?
Cadmium accumulation depends on the soil, but mainly the type
of cultivar grown on that soil. There are cultivars which typically act as "high"
accumulators, and those that act as "low" accumulators, regardless on
the soil that cultivars are grown on.
The accumulation of Cd by soybeans
depends on the "availability" of Cd in the soil. As Cd present in the
soil is mostly bound or "unavailable".
Soil factors which increase
Cd availability are:
- acidic pH
- sandy soils
- and soil which has
relatively low calcium, magnesium and manganese present
Our conclusions
- Genetics is a significant factor in determining the proportion of soil cadmium
that soybeans accumulate.
- Cultivars studied consistently performed as
"high" accumulators or "low" accumulators. A simple way to
reduce risk is to choose low accumulating cultivars.
- There are several
soil variables which affect cadmium availability in soil.
- The most significant
soil variables appear to be the amount of cadmium, calcium and magnesium, as well
as the soil pH.
