Organophosphorus flame retardants in a typical freshwater food web: Bioaccumulation factors, tissue distribution, and trophic transfer

Water, sediment, and wild aquatic species were collected from an electronic waste (e-waste) polluted pond in South China. This study aimed to investigate the bioaccumulation, tissue distribution, and trophic transfer of organophosphorus flame retardants (PFRs) in these aquatic organisms. The concentrations of PFRs detected in the analyzed organisms were between 1.7 and 47 ng/g wet weight (ww). Oriental river prawn and snakehead exhibited the highest and lowest levels, respectively. Tri-n-butyl phosphate (TnBP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCPP) and triphenyl phosphate (TPhP) were dominant contaminants, accounting for approximately 86% of the total sum. The mean values of bioaccumulation factors (BCFs) and logarithmic biota-sediment accumulation factors (log BSAFs) for individual PFRs varied from 6.6 to 1109 and from -2.0 to 0.41, respectively. Both log BCFs and log BSAFs of PFRs were significantly and positively correlated with their octanol-water partitioning coefficient (log KOW). The concentrations of PFRs in tissues of large mud carp and snakehead were significantly and positively correlated with the lipid content (each p < 0.05) and the liver, kidney, and gill exhibited high PFR levels. When the concentration was expressed on a lipid basis, liver exhibited the lowest level, indicating the probable effects of metabolism. Significantly positive correlation was also found between lipid content and total PFR concentration in muscle of all aquatic organisms, given the strong correlation between lipid content and the concentration of TnBP. Trophic magnification factors (TMF) of TnBP and TPhP were lower than 1 (0.57 and 0.62), indicating that these PFRs undergo trophic dilution in this aquatic food web.