Novel control and steady‐state correction method for standard 28‐day bioaccumulation tests using Nereis virens

Abstract

Evaluation of dredged material for aquatic placement requires assessment of bioaccumulation potentials for benthic organisms using standardized laboratory bioaccumulation tests. Critical to the interpretation of these data is the assessment of steady state for bioaccumulated residues needed to generate biota sediment accumulation factors (BSAFs) and to address control correction of day 0 contaminant residues measured in bioassay organisms. This study applied a novel performance reference compound approach with a pulse-chase experimental design to investigate elimination of a series of isotopically labeled polychlorinated biphenyl ((13)C-PCBs) in the polychaete worm Nereis virens while simultaneously evaluating native PCB bioaccumulation from field-collected sediments. Results demonstrated that all (13)C-PCBs, with the exception of (13)C-PCB209 (> 80%), were eliminated by more than 90% after 28 d. The three sediment types yielded similar (13)C-PCB whole-body elimination rate constants (k(tot)) producing the following predictive equation: log k(tot) = - 0.09 × log K(OW) - 0.45. The rapid loss of (13)C-PCBs from worms over the bioassay period indicated that control correction, by subtracting day 0 residues, would result in underestimates of bioavailable sediment residues. Significant uptake of native PCBs was observed only in the most contaminated sediment and proceeded according to kinetic model predictions with steady-state BSAFs ranging from 1 to 3 and peaking for congeners of log K(OW) between 6.2 and 6.5. The performance reference compound approach can provide novel information about chemical toxicokinetics and also serve as a quality check for the physiological performance of the bioassay organism during standardized bioaccumulation testing.

Toxicokinetics of chiral polychlorinated biphenyls across different species—a review

“…The marine worm species Nereis diversicolor and Nereis virens are used as biomonitors for PCB contamination in the sediment compartment of aquatic ecosystems (Bennett et al 2011, Durou et al 2007). Nereis diversicolor is capable of metabolizing some PCB congeners, such as PCB 52, to polar biotransformation products (Goerke and Weber 2001).…”

“…This difference in elimination half-lives is potentially due to differences in the biotransformation of the PCB congeners under investigation and suggests that PCB 95 undergoes no or only slow biotransformation in Nereis diverisolor . Another worm species, Nereis virens, exhibits total body elimination rate constants an order of magnitude higher than Nereis diverisolor, effectively eliminating more than 90% of PCB body burden (Bennett et al 2011). The whole body elimination rate constants for PCBs 95 and 149 are 0.10 and 0.09 d −1 , respectively.…”

“…Specifically, PCBs 95 and 149 have elimination rates ranging from 0.301 to 0.367 d −1 in both species. In both studies, the PCB depuration strongly depends on the experimental conditions, including the duration of the uptake and depuration phases, the temperature and the lipid composition of the organism (Bennett et al 2011, Van Geest et al 2011), and likely does not involve PCB metabolism.…”

Quantitative thermodynamic exposure assessment of PCBs available to sandworms (Alitta virens) in activated carbon remediated sediment during ongoing sediment deposition

“…[17][18][19][20] In addition, polymers are being explored as a tool to predict bioaccumulation, as HOC concentrations in polymer and HOC concentrations in biota lipid are highly correlated. [21][22][23] Consequently, the most immediate implementation of the polymeric sampling techniques, into existing risk assessment and monitoring frameworks, might be to replace organic carbon normalized bulk-phase sediment measurements in the Biota-Sediment Accumulation Factor (BSAF) [24][25][26][27][28][29][30][31] with polymeric sampling of the sediment. 17,18,[20][21][22] While the need for this type of assessment has been known for two decades, 32,33 the practical implementation of polymers and BSAFs at contaminated sediment sites, undergoing remediation with AC, is still an area of scientic inquiry and debate.…”

“…6,39 The use of sandworms (A. virens; formerly Nereis virens), has implications on the bioturbation, fate, and transport of HOCs like PCBs. 6,36,40,41 Large marine sandworms make U-shaped galleries or burrows 39,41 approximately 8-10 cm in depth, 27,28,40 with maximum depths of 45 cm in the eld. 42 The sandworms irrigate the burrows, and the burrow walls provide for more contaminant transport than uncolonized bed sediment.…”