Impacts of crab bioturbation on the fate of polycyclic aromatic hydrocarbons in sediment from the Beitang estuary of Tianjin, China

Abstract

Bioturbation by the burrowing crab Helice tiensinensis was investigated to determine its impact on polycyclic aromatic hydrocarbon (PAH)-contaminated estuarine sediments. The concentrations of 16 U.S. Environmental Protection Agency (U.S. EPA) priority PAHs in sediment and pore water from a crab bed (including surface and burrow samples) and a control area, as well as in crabs, were measured. The total concentration of the 16 U.S. EPA priority PAHs in surface sediment of the crab bed (average 2,772 ng/g dry weight) was significantly higher than in the control area (1,173 ng/g dry weight). In the crab bed, the total concentration of PAHs in burrow sediment (1,239 ng/g dry weight) was lower than in surface sediment, and a similar trend was found for most of the individual PAHs, except for indeno[1,2,3-cd]pyrene, and benzo[ghi]perylene. The enhanced PAH desorption in the burrow, which could be attributed to the increase in dissolved organic matter in pore water as well as the mechanical mixing by the crab, is expected to increase PAH flux to the sea. In addition to increased flushing to the sea, incorporation of PAHs in crab biomass and metabolism of PAHs by the crab, stimulated microbial degradation, was proposed as an ignorable factor that lowered the PAH concentration in burrow sediment, because crab bioturbation increases the abundance and activity of microorganisms through several means. Log K(OW) and log K(OC) correlated well for individual PAHs in sediment in the control area, although this correlation was poor for sediments in the crab bed. The log biota-sediment accumulation factor (BSAF) of PAHs exhibited a negative relationship with log K(OW), suggesting that the bioaccumulation of sorbed PAHs was controlled primarily by their bioavailability.

Influence of bioturbation on bioavailability and toxicity of PAHs in sediment from an electronic waste recycling site in South China

“…Meanwhile, C s24 /C s values among all treatments were similar ( $ 0.48), indicating no significant change in PAH desorption from sediment (Table 3). Enhanced desorption of sediment-associated HOCs in the presence of benthic organisms has been reported in previous field studies (Josefsson et al, 2010;Qin et al, 2010), suggesting that bioturbation not only promoted the transport of HOCs to overlying water by resuspension of sediment particles, but also elevated freely dissolved HOCs in pore water. However, no significant change in bioavailability, estimated by biomimetic techniques, was observed in the present study, which may be an artifact of conducting laboratory-based testing (limited sediment volume and testing time differences).…”

Effect of Cosolutes on the Sorption of Phenanthrene onto Mineral Surface of River Sediments and Kaolinite

“…The OC content of the natural sediment used in this study was 0.27%, which is much lower than those of the sediments in other areas (1.2%–11%) [17, 18]. The natural sediment possessed intermediate BET surface area (4.68 m 2 /g) and pore volume (1.26 × 10 −2 cm 3 /g) among the three sorbents.…”

Quantitative evaluation of in-situ bioremediation of compound pollution of oil and heavy metal in sediments from the Bohai Sea, China

“…The total organic carbon (TOC) in the sediment was determined by potassium dichromate-sulfuric acid oxidation method (Qin et al, 2010). According to multiple sediment analyses, the precision of this method was within 5.0%.…”