Lumbriculus variegatus was used as a bioassay organism to examine the impact of the sediment-associated polycyclic aromatic hydrocarbon (PAH) fluoranthene on behavior, reproduction, and toxicokinetics. The number of worms increased between the beginning and end of the experiment at 59 μg g-1 fluoranthene, but at the next higher treatment (108 μg g-1) the number of worms found was lower and not different from the control. Worms exposed to 95 μg g-1 also exhibited increased reproduction when fed a yeast-cerophyl-trout chow mixture. On a total biomass basis, only the 95 μg g-1 exposure with food exhibited a statistically significant increase over the nonfed control. Evaluation of reproduction at the two highest treatments was compromised by a brief aeration failure 2 days before the end of the experiment. The behavioral responses were followed as changes in biological burial rate (sediment reworking rate) of a 137Cs-labeled marker layer. The biological burial rate increased toward a plateau as the concentration increased from the control (3.9 μg g-1 dry weight total PAH) to 355 μg g-1 dry weight fluoranthene in sediment. The aeration failure had minimal impact on the determination of reworking rate because all the data for the rate determination were collected prior to the aeration failure. Uptake and elimination rates declined with increasing treatment concentration across the range of fluoranthene concentrations, 59–355 μg g-1 dry weight sediment. The disconnect between the increasing biological burial rates and the decreasing toxicokinetics rates with increasing exposure concentration demonstrates that the toxicokinetic processes are dominated by uptake and elimination to interstitial water. The bioaccumulation factor (concentration in the organisms on a wet weight basis divided by the concentration in sediment on a dry weight basis) ranged from 0.92 to 1.88 on day 10 and declined to a range of 0.52 to 0.99 on day 28 with the lowest value at the highest dose. [ABSTRACT FROM AUTHOR]
CHIRONOMUS, HYALELLA, LUMBRICULUS variegatus, WATER pollution, and POLLUTANTS
In situ toxicity and bioaccumulation tests with Ceriodaphnia dubia (48 h), Chironomus tentans (96 h), Hyalella azteca (96 h), and Lumbriculus variegatus (96 h) were conducted at three stations on a river that was contaminated primarily with chlorobenzenes (CBs), and results were compared to a nearby reference site. Exposures were characterized by using minipiezometers for contaminant profiling and determination of hydraulic heads and vertical flow direction within the sediments and measuring contaminants in sediment, surface water, and exposure chamber water samples. Localized zones of upwelling and downwelling existed in the exposure areas at contaminated sites 5 and 18, while site 23 was downwelling at all measurement positions. Porewater samples from minipiezometers contained CBs at the three contaminated sites that were highest at site 23. However, sediment and water samples from exposure chambers at site 23 contained the lowest levels of CBs among the contaminated sites. The CBs were not detected at the reference site, but other organic contaminants and metals were detected at all sites, with the highest concentrations occurring at sites 5 and 18. In water column exposures, no significant (p > 0.05) differences were observed in species survival between the contaminated sites and the reference. Mean percentage survival of H. azteca, C. dubia, and C. tentans exposed to surficial sediments (SS) at sites 5 and 18 was significantly (p < 0.05) reduced compared to the reference, whereas only C. tentans survival was significantly reduced at site 23. Body residues of total CB congeners in L. variegatus exposed to SS were highest at site 18 (618 µmol/kg lipid) and lowest at site 23 (21 µmol/kg lipid). The data suggest that downwelling reduced the bioavailability of CBs in surficial sediments, most likely by mobilizing the freely dissolved and colloid-bound fractions to deeper sediments. Overall, downwelling conditions reduced the in situ exposure of organisms in surficial sediments and hence the toxicity and bioaccumulation of CBs. Hydrologic and chemistry data from nested minipiezometers improved the interpretation of exposure- effects relationships. [ABSTRACT FROM AUTHOR]
Speicea, J., Haricness, J., Laneri, H., Franicel, R., Roter, D., Kcornblith, A. B., Ahles, T., Winer, E., Fleishman, S., Luber, P., Zevona, M., McQuellon, R., Trief, P., Finkel, J., Spira, J., Greenberg, D., Rowland, J., and Holland, J. C.
Latov, N., Hays, A. P., Donofrio, P. D., H. Ito, J. Liao, McGinnis, S., Manoussos, K., Freddo, L., Shy, M. E., Sherman, W. H., Chang, H. W., Greenberg, H. S., Albers, J. W., Alessi, A. G., Keren, D., Yu, R. K., Rowland, L. P., Kabat, E. A., Liao, J, Ito, H, and Konstadoulakis, M