Assessing the Bioaccumulation of Contaminants from Sediments of the Upper Mississippi River Using Field-Collected Oligochaetes and Laboratory-Exposed Lumbriculus variegatus

Abstract

Concern with the redistribution of contaminants associated with sediment in the upper Mississippi River (UMR) arose after the flood of 1993. This project is designed to evaluate the status of sediments in the UMR and is one article in a series designed to assess the extent of sediment contamination in navigational pools of the river. Companion articles evaluate sediment toxicity and benthic community composition in navigation pools of the river. The objectives of the present study were to: (1) to assess the bioaccumulation of sediment-associated contaminants in the UMR using laboratory exposures with the oligochaete Lumbriculus variegatus, and (2) to compare bioaccumulation in laboratory-exposed oligochaetes to field-collected oligochaetes. Sediment samples and native oligochaetes were collected from 23 navigational pools on the Upper Mississippi River and the Saint Croix River. Contaminant concentrations measured in the L. variegatus after 28-day exposures to sediment in the laboratory were compared to contaminant concentrations in field-collected oligochaetes from the 13 pools where these sediments were collected. Contaminant concentrations were relatively low in sediments and tissues from the pools evaluated. Only polycyclic aromatic hydrocarbons (PAHs) and total polychlorinated biphenyls (PCBs) were frequently measured above detection limits. The majority of the biota-sediment-accumulation factors (BSAFs) for PAHs were within a range of about 1.0 to 2.6, suggesting that the theoretical BSAF value of 1.7 could be used to predict these mean BSAFs with a reasonable degree of certainty. A positive correlation was observed between lipid-normalized concentrations of PAHs detected in laboratory-exposed and field-collected oligochaetes across all sampling locations. Rank correlations for concentrations of individual compounds between laboratory-exposed and field-collected oligochaetes were strongest for benzo(e)pyrene, perylene, benzo(b,k)fluoranthene, and pyrene. About 90% of the paired PAH concentrations in laboratory-exposed and field-collected oligochaetes were within a factor of three of one another indicating laboratory results could be extrapolated to the field with a reasonable degree of certainty.

Validation of Ontario's new laboratory‐based bioaccumulation methods with in situ field data

“…A 28-d laboratory exposure has been suggested as a standard, because this typically results in tissue residues within 80% of steady state [10]. This test duration has been validated in a number of studies that found reasonable agreement between tissue residues of field-collected and laboratory-exposed organisms, including for most PCDD/F congeners [21][22][23][24][25]. This comparative approach assumes that organisms in both the laboratory and the field have reached steady-state concentrations.…”

Measuring bioaccumulation of contaminants from field‐collected sediment in freshwater organisms: A critical review of laboratory methods

“…Other PAHs, as well as DDE and DDD, appeared to reach steady-state between 14 and 28 d. This study also compared steady-state concentrations from laboratory exposures with field-collected oligochaetes and found that concentrations in tissue were similar. Other comparisons of 28-to 30-d laboratory exposures with field-collected oligochaetes found that organisms accumulated similar concentrations of PAHs [54] and PCBs [24]. However, it was observed that concentrations of highly chlorinated PCB congeners (hepta to deca) were slightly higher in field organisms, suggesting that 30 d was insufficient for these very hydrophobic compounds (log K OW > 7) to reach steady-state in the laboratory [24].…”

“…The concentration of TOC in sediment also may influence the bioavailability of contaminants through sorption/desorption, causing increased variability in BSAFs between sites. Many researchers now calculate a BSAF in which the concentration of the organic contaminant is normalized to both lipid and sediment organic carbon [37,44,54]. The resulting BSAF has the units organic carbon/ lipid and is theoretically independent of species or sediment type.…”

Essai n° 225: Essai de toxicité sur Lumbriculus dans un système eau-sédiment chargé

“…Les conditions de culture de Lumbriculus variegatus sont détaillées dans Phipps et al (1993) (1), Brunson et al (1998) (2), ASTM (2000) (3), U.S. EPA (2000) (4). Un bref résumé de ces conditions est présenté cidessous.…”

“…Les animaux endobenthiques qui ingèrent des sédiments sont soumis à un risque d'exposition substantielle aux substances liées aux sédiments, et soulèvent par conséquent un grand intérêt, par exemple (1), (2), (3). Parmi les organismes de ce type, les oligochetes aquatiques jouent un rôle important dans les sédiments des systèmes aquatiques.…”