Bioaccumulation of Polycyclic Aromatic Hydrocarbons (PAHs) by the Marine Clam, Mactra veneriformis, Chronically Exposed to Oil-Suspended Particulate Matter Aggregates

Abstract

Dispersion and biodegradation of petroleum hydrocarbons are significantly enhanced by formation of oil-suspended particulate matter aggregates (OSAs), but little is known about their adverse effects on benthic invertebrates or microbes. In this study, we investigated: (1) bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) by the marine bivalve, Mactra veneriformis and (2) changes in composition and relative abundances of microbes, during 50-d of an OSAs feeding experiment. Total concentrations of PAHs increased more rapidly during the first week of exposure, peaked at Day 30, then gradually declined to the end of experiment. While bioaccumulation of PAHs by clams varied among the 20 target compounds, two major groups of PAHs were identified by cluster analysis. One group including 3-methylphenanthrene, 1,6-dimethylphenanthrene, 1,2,6,9-tetramethylphenanthrene, and benzo[ a]anthracene showed a fairly constant rate of accumulation, while the second group including 2-methyldibenzothiophene, 2,4-dimethyldibenzothiophene, 2,4,7-trimethyldibenzothiophene, 3-methylchrysene, 6-ethylchrysene, and 1,3,6-trimethylchrysene exhibited a bell-shaped pattern. Bioaccumulation of PAHs by clams was dependent on changes in abundance of Gammaproteobacteria, indicating active degradations of hydrocarbons by selected species. Six key species included: Porticoccus litoralis, Porticoccus hydrocarbonoclasticus, Cycloclasticus spirillensus, Alcanivorax borkumensis, Alcanivorax dieselolei, and Alkalimarinus sediminis. These results are the first to demonstrate interactions of OSAs and macrofauna/microbe in oil cleanup operations.

Bioaccumulation and toxicokinetics of polycyclic aromatic compounds and metals in giant floater mussels (Pyganodon grandis) exposed to a simulated diluted bitumen spill

“…Regardless, consistent with results from this experiment, a number of mussel studies have reported that it would take longer than 25 days for most PACs to reach steady state (Baussant et al, 2001;Enwere et al, 2009;Hwang et al, 2008;Noh et al, 2018;Richardson et al, 2005;Thorsen et al, 2004;H. Wang et al, 2017;Yakan et al, 2011).…”

“…Some of the PACs increased rapidly during the first few time points of the uptake phase and then slowed down as their concentrations approached steady state while most PACs increased in mussel tissue steadily through time, never approaching steady state. This makes sense as several bivalve exposure studies have reported that it takes longer than 25 days for most PACs to reach steady state (Baussant et al, 2001;Enwere et al, 2009;Hwang et al, 2008;Noh et al, 2018;Richardson et al, 2005;Thorsen et al, 2004;H. Wang et al, 2017;Yakan et al, 2011).…”

Effects of Dispersants and Biosurfactants on Crude-Oil Biodegradation and Bacterial Community Succession

“…are not known hydrocarbon degraders. However, recently, A. sediminis was found to significantly increase in relative abundance when PAHs bioaccumulated in bivalves [112]. Superdispersant 25 resulted in a significant increase in the relative abundance of ASV21 from the genus Neptuniibacter (97.34% 16S rRNA sequence identity to N. marinus strain CECT 8938; Figure 3) after 3 days.…”

Impact of Polycyclic Aromatic Hydrocarbon Accumulation on Oyster Health

“…Gastropods and bivalves are two different classes of mollusks commonly used as bioindicators (O'Connor, 2002;Rittschof and McClellan-Green, 2005;Noh et al, 2018;Pham et al, 2020). Of these two, bivalves are potentially better suited for biomonitoring due to their sedentary lifestyle and filter-feeding.…”