Uptake of PCBs contained in marine sediments by the green macroalga Ulva rigida

The uptake of PCBs contained in marine sediments by the green macroalga Ulva rigida was investigated in both laboratory and field experiments. Under laboratory conditions, total PCBs (tPCBs) uptake was significantly greater in live vs dead plants. The concentration of tPCB taken up in live plants was greatest in the first 24 h (1580 μg kg−1 dry weight), and then increased at a lower rate from day 2 to 14. Dead plants had a significantly lower tPCB concentration after 24 h (609 μg kg−1 dry weight) and lower uptake rate through day 14. Lesser chlorinated PCB congeners (below 123) made up the majority of PCBs taken up. Congener composition in both laboratory and field experiments was correlated to congener log Kow value and sediment content. Field experiments showed that Ulva plants could concentrate PCBs to 3.9 mg kg−1 in 24 h. Thus, U. rigida is capable of removing PCBs in sediments at a rapid rate.