Bioavailability of PAHs:  Effects of Soot Carbon and PAH Source

Abstract

The bioavailability of 38 individual polycyclic aromatic hydrocarbon (PAH) compounds was determined through calculation of biota-sediment-accumulation factors (BSAF). BSAF values were calculated from individual PAH concentrations in freshwater mussel, marine clam, and sediment obtained from field and laboratory bioaccumulation studies. Sediment that was amended with different types of soot carbon (SC) was used in some of the bioaccumulation experiments. BSAF values for petrogenic PAH were greater than those for pyrogenic PAH (e.g., 1.57 +/- 0.53 vs 0.25 +/- 0.23, respectively), indicating that petrogenic PAH are more bioavailable than pyrogenic PAH (p < 0.05). This trend was consistent among marine and freshwater sites. Increased SC content of sediment resulted in a linear decrease in the bioavailability of pyrogenic PAHs (r2 = 0.85). The effect of increasing SC content on petrogenic PAH was negligible. SC was considered as an additional sorptive phase when calculating BSAF values, and using PAH-SC partition coefficients from the literature, we obtained unreasonably large BSAF values for all petrogenic PAH and some pyrogenic PAH. This led us to conclude that a quantitative model to assess bioavailability through a combination of organic carbon and soot carbon sorption is not applicable among field sites with a wide range of soot carbon fractions and PAH sources, at least given our current knowledge of PAH-SC partitioning. Our data offer evidence that many factors including analysis of a full suite of PAH analytes, PAH hydrophobicity, sediment organic carbon content, sediment soot carbon content, and PAH source are importantto adequately assess PAH bioavailability in the environment.

Influences of multiwalled carbon nanotubes and plant residue chars on bioaccumulation of polycyclic aromatic hydrocarbons by Chironomus plumosus larvae in sediment

“…Biota sediment accumulation factor was used to evaluate the bioaccumulation of PAHs in larvae, which was calculated with the following formula [35] BSAF ¼ C tissue; lipid C s; OC (3) where BSAF is the biota sediment accumulation factor (kg OC /kg lipid ); C tissue,lipid is the lipid-normalized concentration in organisms (mg/kg lipid ); and C s,OC is the organic carbon normalized concentration of PAHs in sediment (mg/kg OC ), which was calculated as C s divided by organic carbon in the original sediment. The nominal concentrations of PAHs in sediment were the total sorbed concentrations of PAHs in sediment (mg/kg sediment ), which could be estimated as the initial concentration of PAHs in the sediment system after spiking because the PAH quantity in the water phase was three orders of magnitude lower than in the solid phase.…”

Occurrence, distribution, sources and toxic potential of polycyclic aromatic hydrocarbons (PAHs) in surface soils from the Kumasi Metropolis, Ghana

“…Many PAHs are mutagenic and some are carcinogenic and these raise concerns over their occurrence in the environment (Flowers et al, 2002;Thorsen et al, 2004;Cornelissen et al, 2006). Due to their high hydrophobic properties, PAHs can be sorbed on atmospheric particles and thus transported over a long distance, being a source of diffuse pollution (Wilcke, 2007;Ravindra et al, 2008).…”

Effects of humic acid and lipid on the sorption of phenanthrene on char

“…Sorption of hydrophobic organic compounds (HOCs) on BC is up to 10-1000 times greater than that of soil organic matter (Cornelissen et al, 2005). BC has been reported to limit the availability of HOCs (Thorsen et al, 2004;Moermond et al, 2005;Brown et al, 2006). Therefore, it is considered as a cost-effective material for controlling the fate and remediation of anthropogenic contaminants (Koelmans et al, 2006).…”