Empirical relationships between polychlorinated biphenyls in sediments andsubmerged rooted macrophytes

In this study, we use empirical relationships to model accumulation of poly chlorinated biphenyls (PCBs) in submerged rooted macrophytes sampled in the upper St. Lawrence River (Canada - United States). The correlations betwee n PCB congener concentrations in sediments, in macrophyte shoots, and in th eir roots were all significant (P < 0.001). However, the PCB congener conce ntrations in macrophyte shoots were better predicted by concentrations in s ediments (top 5 cm) than by those in the roots of plants (R-2 = 0.839 and 0 .704, respectively). Our results suggest that models based on the phase par titioning concept are applicable to submerged macrophytes. The lipids in sh oots and the organic fraction in sediments are likely the phases involved i n PCB partitioning between these two compartments. Between shoots and roots , the lipid phase also appears to be involved in the congener partitioning. However, between roots and sediments (5- to 10-cm depth interval), the cor relation was weaker using organic weight standardisation of congener concen trations in sediments than using dry weight standardisation (R-2 = 0.852 an d 0.778, respectively).