The accumulation of cadmium by the yellow pond lily, Nuphar variegatum, in Ontario peatlands.

Abstract

Cadmium concentrations of a common macrophyte, the yellowpond lily (Nuphar variegatum) were investigated from peatlands with arange in pH (4.4-6.3), alkalinity (0-181 microeq/L Ca), DOC (5.1-16.8 mg/L), and sediment organic content (20-88%). Cd concentrations inNuphar ranged from 0.3 to 1.51 microg/g in the leaves and from 0.46 to1.51 microg/g in the petioles, and was significantly higher in the petiolesthan in the leaves (p = 0.014; t-Test). Significant and negativecorrelations between Nuphar leaf Cd and pH (r2 =0.76; p < 0. 001), alkalinity (r2 = 0.41; p =0.034), and DOC (r2 = 0.46; p = 0. 022) wereobtained. In addition, a significant and negative correlation was foundbetween Nuphar petiole Cd and pH (r2 = 0.46; p= 0.023). These results indicate that the leaves of Nupharfound in peatlands of low pH, low alkalinity, and low DOC, and the petiolesof Nuphar found in peatlands of low pH are more susceptible toaccumulating potentially toxic levels of Cd. The organic content of thepeatland sediments was not significantly correlated with either the leaf orpetiole Cd concentration. Nuphar is an important food source for manywetland animals; any Cd that is present in these plants may be passed ontoother trophic levels because diet is considered to be the major source of Cdto animals.