Trace metals in wild rice sold in the United States

North American wild rice (Zizania aquatica L. and Z. palustris L.) grows in moderately soft and acidic freshwater wetlands. With the increasing pollution of such a habitat, there is some concern that the trace metal contents of the rice crop have become unduly elevated. This study finds moderately elevated levels of lead (0.5–11.5 μg/100 g dry wt.), cadmium (1.0–10.2 μg/100 g dry wt.) and arsenic (0.6–14.2 μg/100 g dry wt.) in 26 brands of wild rice sold in the United States. The high concentrations of iron (2.0–9.7 mg/100 g dry wt.), copper (0.2–1.3 mg/100 g dry wt.) and zinc (0.1–0.4 mg/100 g dry wt.) suggest that wild rice may be a good dietary source of these essential elements.