Effect of nitrogen and phosphorus concentrations on the adsorption of BDE28 and BDE47 by Prorocentrum donghaiense dominant population

The adsorption of 2,4,4′-Tribromodiphenyl ether(BDE28) and 2,2′,4,4′-Tetrabromodiphenyl ether(BDE47) by Prorocentrum donghaiense dominant population under different nitrogen and phosphorus concentrations was studied.Prorocentrum donghaiense dominant population consisted of Prorocentrum donghaiense and Skeletonema costatum,in which Prorocentrum donghaiense was dominant.Nitrogen was in form of nitrate and the concentrations tested were 0,128 and 512 μmol·L-1,and phosphorus was in form of phosphate and the concentrations tested were 0,8 and 32 μmol·L-1.The algal density and biochemical composition were determined and the correlation between the adsorption and the biochemical composition was analyzed.The results showed that the BDE28 and BDE47 adsorbed per cell was 2.2 and 2.9 ng·(106 cells)-1 respectively when nitrogen concentration was 0 μmol·L-1,which was 1.3-1.9 times as high as those under 128 and 512 μmol·L-1 nitrogen.There was no significant difference in the amount of polybrominated diphenyl ethers(PBDEs) adsorbed per culture and the adsorbed percentage of available PBDEs among different nitrogen concentrations.In nitrogen treatments,the amount of PBDEs adsorbed per culture was 0.160-0.184 ng·mL-1 and the adsorbed percentage of available PBDEs was 80.2%-92.1%.The BDE28 and BDE47 adsorbed per cell was 7.6 and 8.4 ng·(106 cells)-1 respectively when phosphorus was 0μmol·L-1,which was 5.4-6 times as high as those under 8 and 32 μmol·L-1 phosphorus.There was no significant difference in the amount of PBDEs adsorbed per culture and the adsorbed percentage of available PBDEs among different phosphorus concentrations.In phosphorus treatments,the amount of PBDEs adsorbed per culture was 0.167-0.194 ng·mL-1 and the adsorbed percentage of available PBDEs was 80.2%-93.2%.Correlation analysis indicated that there was a significant negative correlation between nitrogen concentrations and the amounts of BDE28 and BDE47 adsorbed per cell and a significant positive correlation between phosphorus and the amount of PBDEs adsorbed per culture as well as the adsorbed percentage of available PBDEs.Besides,a significant positive correlation was found between the PBDEs adsorption and the amount of lipids.Nitrogen and phosphorus induced the change of biochemical content which resulted in the change of the adsorption of BDE28 and BDE47.