Application of a tenax model to assess bioavailability of polychlorinated biphenyls in field sediments

Abstract

Recent literature has shown that bioavailability-based techniques, such as Tenax extraction, can estimate sediment exposure to benthos. In a previous study by the authors, Tenax extraction was used to create and validate a literature-based Tenax model to predict oligochaete bioaccumulation of polychlorinated biphenyls (PCBs) from sediment; however, its ability to assess sediment remediation was unknown. The present study further tested the Tenax model by examining the impacts of remediation on surface sediment concentrations, Tenax extractable concentrations, and tissue concentrations of laboratory-exposed Lumbriculus variegatus. Tenax extractable concentration was an effective exposure metric to evaluate changes in Lumbriculus exposure preremediation and postremediation, with 75% of the postremediation data corresponding to the Tenax model. At nondredged sites, bioaccumulation was better predicted by the Tenax model, with 86% of the data falling within the 95% confidence intervals, than at dredged sites, for which only 64% of the data fit the Tenax model. In both pre- and postdredge conditions, when the model failed, it was conservative, predicting higher PCB concentrations than observed in the oligochaetes, particularly for the postdredge data. The present study advances understanding of the applicability of the Tenax model for use when examining systems that may have undergone significant disturbances. The Tenax model provides a unique tool for quickly quantifying potential exposure to benthic organisms.

Impact of bioaccessible pyrene on the abundance of antibiotic resistance genes during Sphingobium sp.- and sophorolipid-enhanced bioremediation in soil

“…The values of F r , F sl , F vl, k r , k sl , and k vl were calculated by minimizing the cumulative squared residuals between experimental and derived values of ln (S t /S 0 ) [30].…”

Tenax extraction as a simple approach to improve environmental risk assessments

“…Only 64% of the measured bioaccumulation values fell within the 95% confidence interval of the model when correlated with the measured Tenax-extractable concentrations from dredged sites compared with 86% of the values from undisturbed sites falling within the 95% confidence interval of the bioaccumulation Tenax model [26]. The reduced accuracy of the model during that study was attributed to effects of remediation on the feeding habits of the oligochaetes in the field, which may have reduced bioaccumulation below what would be expected in an undisturbed site [26]. This may indicate that under some conditions there is no better surrogate for exposure than tissue concentrations.…”

“…The reduced accuracy of the model during that study was attributed to effects of remediation on the feeding habits of the oligochaetes in the field, which may have reduced bioaccumulation below what would be expected in an undisturbed site [26]. However, as in the preremediation study, the model-based estimates would have produced a conservative estimate of bioaccumulation, allowing for protective risk evaluation [26], thus compensating somewhat for the reduced accuracy of the model (Figure 3). However, as in the preremediation study, the model-based estimates would have produced a conservative estimate of bioaccumulation, allowing for protective risk evaluation [26], thus compensating somewhat for the reduced accuracy of the model (Figure 3).…”

Tenax extraction of sediments to estimate desorption and bioavailability of hydrophobic contaminants: A literature review

“…This approach was extended to examine the Ottawa River postremediation. In this case, the model was slightly less accurate (Mackenbach et al ). In general, the model predicted the nondredged sites with an accuracy of 86% of the data within the 95% confidence interval of the model and with 64% the dredged sites fitting in the same interval.…”