Cadmium, copper and lead in wild rice from central Canada.

Samples of wild rice grains available for sale in Manitoba, Canada contained < 0.01-6.2 micrograms/g cadmium, < 0.01-6.7 micrograms/g lead, and 1.6-14.4 micrograms/g copper. Rice originating from Saskatchewan and northern Manitoba contained significantly higher copper concentrations than samples from Ontario and southeastern Manitoba. Larger and heavier grains contained higher lead concentrations per unit weight. Mean content of all three metals per individual grain was exponentially correlated with grain size and weight. Total soluble carbohydrate and soluble protein concentrations were negatively correlated with copper concentrations.