Citation:

Tabak, H H., J. M. Lazorchack, M E. Smith, AND J. A. Ferretti. A TOXICITY ASSESSMENT APPROACH FOR THE EVALUATION OF IN-SITU BIOREMEDIATION OF PAH CONTAMINATED SEDIMENTS. Chapter 27, Gary K. Ostrander (ed.), Techniques in Aquatic Toxicology, Volume II. CRC Press LLC, Boca Raton, FL, , 479-509, (2005).

Description:

Freshwater and marine sediment toxicity test were used to measure baseline toxicity of sediment samples collected from New York/New Jersey Harbor (NY/NJH) and East River (ER) (PAH contaminated) sediments and to determine the effectiveness of the developed biotreatment strategies in reducing the ecotoxicity of the contaminated sediments. Four freshwater toxicity tests using amphipods, aquatic worms, fathead minnow larvae and a vascular plant (Duckweed) and two marine tests using a marine amphipod and sheepshead minnow larvae were employed in the study. To determine the cause of toxicity in these sediments, five sediment manipulations were performed: a sediment purge procedure, a sediment dilution procedure, a sediment aeration procedure, Ambersorb 563 and 572 resin treatment procedures for removal of organic contaminants and an Amberlite IRC-718 resin treatment procedure for removal of inorganics (metals).
ER sediment was found to be highly toxic to all freshwater and marine organisms tested while the NY/NJH sediment showed no significant toxicity to the marine amphipod but was slightly toxic to the freshwater worm and to freshwater and marine fish larvae. For all tests run on ER sediment with freshwater organisms and the one marine amphipod, no survival was found. The ER sediment significantly reduced frond production (~58.3%) and chlorophyl a levels (~35.4%) in the freshwater duckweed test. Results from five sediment manipulation studies showed that freshwater amphipod survival was improved with sediment aeration procedure, with 8% Ambersorb 563 and 572 resin as well as with Amberlite IRC-718 resin treatments. Toxicity can also be reduced with the sediment dilution technique (100 fold). These sediment manipulations and analyses for the specific inorganic and organic contaminants revealed that hydrogen sulfide (produced by the sulfate reduction activity of sulfate reducing bacteria), PAHs and metals were factors causing ER sediment toxicity. Results from the amphipod (Hyalella azteca) toxicity tests using ER and NY/NJH sediments treated by aerobic biodegradation slurry approaches showed reduction in toxicity to H. azteca equal to or greater than that achieved through chemical or mechanical manipulations of the sediment samples. H. azteca survival after various aerobic soil slurry biotreatments of ER sediment ranged from 35% to 65% compared to survival of 20% in ER sediment tested after sediment aeration and after addition of 8% Ambersorb 572 resin.
The toxicity assessment approach for evaluation of bioremediation of PAH contaminated sediments using aerobic biodegradation methods is ready to be tested as a viable procedure on a field-scale level to determine the baseline toxicity of the contaminated sediment and the residual toxicity after aerobic biodegradation procedures have been undertaken to the use of the described above sediment manipulatons and treatments with Ambersorb and Amberlite resins.
Similar strategy for toxicity assessment can also be implemented for evaluation of bioremediation of PAH contaminated sediments before and after the implementation of anaerobic biodegradation procedures together with the sediment manipulations and the use of Ambersorb and Amberlite resins. Such studies can provide sufficient information to determine if PAH biodegradation under anaerobic conditions is feasible in certain confined dredged sediment areas to produce significant decrease of exotoxicity of the treated sediments.

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