Toxicological Effects of Three Polybromodiphenyl Ethers (BDE-47, BDE-99 and BDE-154) on Growth of Marine Algae Isochrysis galbana

Polybrominated diphenyl ethers (PBDEs) are highly persistent anthropogenic contaminants found in trace amounts in many environmental compartments far from their source areas, posing a risk to aquatic ecosystems. Our objective was to determine the relative toxicities of three BDEs, BDE-47, BDE-99 and BDE-154 on marine phytoplankton algae Isochrysis galbana. For a highly sensitive endpoint: the 72-h inhibition of autotrophic growth rate was calculated according to standards methods. Actual PBDE concentration was measured by GC-MS and toxicity parameters were calculated on the basis of time-weighted mean actual concentrations. No observable effect concentration (NOEC) values were 2.53 mu g L-1 for BDE-47, 3.48 mu g L-1 for BDE-99 and 12.3 mu g L-1 for BDE-154, and LOEC values were 5.06, 6.96 and 24.60 mu g L-1 for BDE-47, BDE-99 and BDE-154, respectively. The calculated IC10 (the concentration inhibiting growth rate by 10 %) corresponded to 9.3, 12.78 and 54.6 mu g L-1 for BDE-47, BDE-99 and BDE-154, respectively. The 50 % inhibitions of growth rate (IC50) values were: 25.7 mu g L-1 BDE-47, 30.0 mu g L-1 BDE-99 and 243.7 mu g L-1 BDE-154. Therefore, the acute toxicity of PBDEs decreases as the degree of bromination increases, the order of toxicity is BDE-47 > BDE-99 > BDE-154. Significant (p < 0.05) adverse effects were observed for all compounds at concentrations > 15 mu g L-1. Our results indicated that under laboratory conditions PBDEs inhibited the growth of marine phytoplankton at concentrations near 10 mu g L-1. However, further work is required to investigate long-term effects in these and other aquatic organisms.