DESORPTION OF CHLORINATED HYDROCARBONS FROM PHYTOPLANKTON

Studies were conducted to investigate the desorptive characteristics of hexachlorobenzene (HCB) and 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP) sorbed to algal and sediment suspensions by using three approaches: batch equilibration, air purging and competitive exchange. In both short-term and extended batch desorptions, sorption partition coefficients were consistently greater than desorption partition coefficients. Air-purging removed virtually all of the sorbed HCBP within 2 h, exhibiting a two-component release pattern for all tested sorbents. In competitive sorption tests, HCB originally sorbed to suspended sediments was released to be taken up by algae. These studies indicate the importance of sorbent type in the magnitude and strength of sorption for two hydrophobic compounds.