Bioavailability of fluoranthene in freshwater sediment toxicity tests

Abstract

To examine equilibrium‐partitioning model predictions of interstitial water concentrations of fluoranthene as part of the equilibrium‐partitioning (EqP) approach to sediment quality criteria development, the bioavailability (toxicity) of fluoranthene‐amended sediment (a nonpolar organic compound) to Hyalella azteca, Daphnia magna, and Chironomus tentans was determined. Fluoranthene was added to three freshwater sediments with similar organic carbon content (0.44‐0.50%). Although sediments were from divergent sources (Water Research Field Station [WRFS], Trinity River [TR], and Lake Fork [LF]), sediment physical and chemical characteristics did not vary appreciably, leading us to hypothesize (based on EqP theory) that fluoranthene‐amended sediment toxicity would not vary between sediments. Predicted interstitial water concentrations from the equilibrium‐partitioning model were similar to measured interstitial water concentrations for WRFS and TR sediment, but the model underpredicted measured values for LF sediment by a factor of two. EC50s for Daphnia magna, Hyalella azteca, and Chironomus tentans in interstitial water were a factor of two to five greater for LF than for WRFS and TR sediments. Factors other than organic carbon content of sediments (e.g., dissolved organic carbon content in interstitial water) probably contributed to the variability in bioavailability of fluoranthene. Based on 10‐d sediment toxicity tests with Hyalella azteca, Daphnia magna, and Chironomus tentans, organic carbon‐normalized sediment concentrations were better predictors of toxicity than interstitial water and bulk sediment fluoranthene concentrations. In 10‐d aqueous‐phase tests with fluoranthene, Chironomus tentans and Hyalella azteca were twice as sensitive as Daphnia magna. The response of freshwater organisms to fluoranthene‐amended sediment was similar to that of marine organisms exposed to fluoranthene in other studies. The EqP approach for sediment‐quality criteria accurately predicted sediment toxicity for WRFS and TR sediments but not for LF sediment, indicating the model may be overly protective for some bottom sediments. Factors other than organic carbon content may be important in affecting neutral organic compound bioavailability.

Chronic Toxicity Thresholds for Sediment-Associated Benzo[a]pyrene in the Midge (Chironomus dilutus)

“…Verrhiest et al (2001) found in 10-day acute toxicity tests that phenanthrene and fluoranthene caused 50 % mortality of C. riparius at concentrations of 20 and 15 lg/g dw, respectively. The same magnitudes of the 10-day LC50 values (3 to 8.7 lg/g dw) were also reported for C. riparius exposed to fluoranthene (Suedel et al 1993). In addition to the potent of different PAHs, the divergence of LC50 values might be related to different organism stages and lengths of exposure periods used in testing: We used 24-h newly hatched midge larvae and a whole life cycle, whereas the other investigators used third-instar midges plus a 10-day exposure (Suedel et al 1993;Verrhiest et al 2001).…”

“…The same magnitudes of the 10-day LC50 values (3 to 8.7 lg/g dw) were also reported for C. riparius exposed to fluoranthene (Suedel et al 1993). In addition to the potent of different PAHs, the divergence of LC50 values might be related to different organism stages and lengths of exposure periods used in testing: We used 24-h newly hatched midge larvae and a whole life cycle, whereas the other investigators used third-instar midges plus a 10-day exposure (Suedel et al 1993;Verrhiest et al 2001). Earlier, MacDonald et al (2000) reported that in freshwater ecosystems, the probable effect concentration of BaP was 76 lg/g OC, and BaP concentrations inducing the lowest and highest apparent effects were 160 and 360 lg/g OC, respectively.…”

“…1 Table S1, the toxicity of BaP to midges was evident with LC50 values of 92.5 ± 19.6 and 56.9 ± 1.76 lg/g OC after 20-and 43-day exposures, respectively. Information on the chronic toxicity of BaP is sparse, and most studies were focused on the acute toxicity of low-ring PAHs (Suedel et al 1993;Verrhiest et al 2001). Verrhiest et al (2001) found in 10-day acute toxicity tests that phenanthrene and fluoranthene caused 50 % mortality of C. riparius at concentrations of 20 and 15 lg/g dw, respectively.…”

Review and comparison of available testing approaches and protocols for testing effects of chemicals on sediment‐dwelling organisms with potential applicability to pesticides

“…Larval Chironomus riparius and Chironomus tentans have been demonstrated to tolerate a wide range of substrates from particle size ranges >90% silt and clay to 100% sand with no detrimental effects on survival or growth (Environment Canada, 1997 andSuedel et al 1993). However studies incorporating life-cycle and behavioural assessments (Sibley et al 1998) indicate that at least for C. tentans, survival of larvae was significantly reduced in a clay substrate (mean particle size 8 µm) as was time to first emergence.…”

Focus on Field Stations

“…Of particular interest have been the effects of non-ionic surfactants on aquatic invertebrates and fishes in outdoor stream mesocosms (Figueroa 1995. Toxicological studies have encompassed a variety of topics including copper speciation and bioavailability (Suedel et al 1992, Deaver 1995, Sturgis 1995, response of Myriophyllum spicatum to controlled release formulation of fluridone (Wright 1993), and germination and early seedling growth of emergent wetland plants . An EPA-funded EPSCoR project involved a collaborative effort between the University of Mississippi, the University of Mississippi Medical Center, University of Southern Mississippi Gulf Coast Research Laboratory, Jackson State University, and Mississippi State University.…”