Heavy metals transport implications of biotic uptake in the coeur d'Alene River basin

Measurements of the concentrations of 4 metallic elements (Mn, Pb, Zn and Cd) are given for water, soil and plant material from Juncus sp. at 3 locations. Transport of metals from the soil into plant material differs depending on the metal and plant. Root material of plants tends to contain more lead than plant shoots, but manganese, zinc and cadmium are more concentrated in the shoots. Juncus sp. appears to regulate the concentration of Mg and Zn to compensate for soil conditions above or below some desirable range, and excludes Pb from shoots very effectively, but Pb is excluded from roots less effectively. Metallic contaminants incorporated into plant matter can be transported in a plant pathway if the plant material blows, floats or is carried away by animals. Because Pb is excluded from the aerial plant material, transport of Pb in Juncus sp. plant material is minimized. Further information on the incorporation of Pb into plant material of other types would be useful in assessing transport to animals.