Identification of the Sediment-Associated Contaminants in the Illinois River Complex using Toxicity Identification Evaluation (TIE)

The final report for this project “Identification of the Sediment-Associated Contaminants in the Illinois River Complex using a Toxicity Identification Evaluation (TIE)”, conducted by Dr. Michael Lydy and W. Tyler Mehler, is comprised of the thesis of W. Tyler Mehler submitted to the Department of Zoology, Southern Illinois University – Carbondale in December 2009. In addition, two papers have been published which are based on this project: Mehler, W. Tyler, Jonathan D. Maul, Jing You, and Michael J. Lydy. 2009. "Identifying the causes of sediment-associated contamination in the Illinois River (USA) using whole-sediment toxicity identification evaluation." Environmental Toxicology and Chemistry 29(1): 158-167; Mehler, W. Tyler, Jing You, Jonathan D. Maul, and Michael J. Lydy. 2010. "Comparative analysis of whole sediment and porewater toxicity identification evaluation techniques for ammonia and non-polar organic contaminants." Chemosphere 78: 814-821. The thesis and research papers have been subjected to external scientific peer review and may not necessarily reflect the views of the Illinois Sustainable Technology Center.The difficulty of assessing risk of sediment-associated contaminant mixtures to benthic ecosystems is often attributed to understanding the bioavailable fraction of each contaminant. These issues have led to the development of the toxicity identification evaluation (TIE). Past pore water TIE testing on Illinois River sediments has indicated that ammonia was the primary contaminant. The current study, however, suggests that ammonia is no longer the primary contaminant of concern, but rather non-polar organics, including polycyclic aromatic hydrocarbons, are the primary cause for toxicity in the Illinois River Complex (IRC). Summer of 2007 testing showed that six out of the seven sites that proceeded to Phase I testing exhibited a significant increase in survival with the addition of the non-polar organic amendment powdered coconut charcoal (PCC), while zeolite (ammonia amendment) and Resin Tech SIR 300 (cationic metals amendment) did not significantly increase survival suggesting that non-polar organics are the source of toxicity. In addition, Phase II testing suggested that concentrations of PAHs were high enough to cause the observed toxicity, which confirmed the results of Phase I testing. Additional seasonal-based sampling (i.e., fall, winter, spring, and summer 2008) supported the summer findings, with little variation between toxicity and concentrations, with 46% of the sites being improved with the addition of PCC in Phase I testing. The results of Phase I and Phase II contradicted past pore water TIE studies as non-polar organics were suggested as the source of toxicity rather than ammonia. Thus, both pore water and whole sediment TIE methodologies were used on two selected sites. The results of this study suggested that discordance between the past pore water TIEs and the current whole sediment TIE were attributed to the methodologies and on a lesser note the test organisms used. The present study provides data that could be used in combination with previous work to more accurately characterize the sources and spatial trends of toxicity in Illinois River sediments for future risk assessment and mitigation. Furthermore, the present study showed that while TIE methodologies are a valuable tool in assessing risk associated with contaminants in aquatic system, further research in understanding the role that each TIE method may serve in risk assessment is also important.Illinois Sustainable Technology Center/Grant No. HWR07211published or submitted for publicationis peer reviewe

Establishing, improving, and adapting the whole-sediment toxicity identification evaluation (TIE) for use in Australia

© 2018 Dr Wesley Tyler MehlerSediment risk assessments have commonly employed what is known as the ‘conventional’ method to address risk and determine causality of toxic sediments. The ‘conventional’ method compares effects (determined through bioassays) to exposure data (via analytical evaluations of the contaminated sediment). However, this approach has numerous limitations that make the use of this method in many circumstances unreliable (including biasing classification towards priority pollutants and a lack of understanding of issues such as bioavailability and mixtures). In response to these limitations, researchers developed the ‘toxicity-based’ method, which uses the response of organisms to identify causal links. Whole-sediment toxicity identification evaluations (TIEs) are one such, using physical and/or chemical manipulations of the sediment to enhance or decrease the toxicity of a given chemical or chemical class. If the manipulation affects the toxicity of the media this confirms that the toxicant, which was being manipulated, is causing the given effects. This tool is still in its relative infancy, as guidance only became available in 2007 in the United States. To date, this tool has yet to be effectively developed or implemented in Australia. This dissertation provides the foundation for future whole-sediment TIE work in Australia. Additionally, this research expands on past work to make the technique more effective, and adapts it for various types of sediment contamination, such as mining sites. This research complements Northern Hemisphere whole-sediment TIE work, while providing additional techniques and modifications that will assist in making the use of the whole-sediment TIE method more user-friendly, cost-effective, and practical

Identification of the sediment-associated contaminants in the Illinois River Complex using a toxicity identifcation evaluation (TIE)

The difficulty of assessing risk of sediment-associated contaminant mixtures to benthic ecosystems is often attributed to understanding the bioavailable fraction of each contaminant. These issues have led to the development of the toxicity identification evaluation (TIE). Past pore water TIE testing on Illinois River sediments has indicated that ammonia was the primary contaminant. The current study, however, suggests that ammonia is no longer the primary contaminant of concern, but rather non-polar organics, including polycyclic aromatic hydrocarbons, are the primary cause for toxicity in the Illinois River Complex (IRC). Summer of 2007 testing showed that six out of the seven sites that proceeded to Phase I testing exhibited a significant increase in survival with the addition of the non-polar organic amendment powdered coconut charcoal (PCC), while zeolite (ammonia amendment) and Resin Tech SIR 300 (cationic metals amendment) did not significantly increase survival suggesting that non-polar organics are the source of toxicity. In addition, Phase II testing suggested that concentrations of PAHs were high enough to cause the observed toxicity, which confirmed the results of Phase I testing. Additional seasonal-based sampling (i.e., fall, winter, spring, and summer 2008) supported the summer findings, with little variation between toxicity and concentrations, with 46% of the sites being improved with the addition of PCC in Phase I testing. The results of Phase I and Phase II contradicted past pore water TIE studies as non-polar organics were suggested as the source of toxicity rather than ammonia. Thus, both pore water and whole sediment TIE methodologies were used on two selected sites. The results of this study suggested that discordance between the past pore water TIEs and the current whole sediment TIE were attributed to the methodologies and on a lesser note the test organisms used. The present study provides data that could be used in combination with previous work to more accurately characterize the sources and spatial trends of toxicity in Illinois River sediments for future risk assessment and mitigation. Furthermore, the present study showed that while TIE methodologies are a valuable tool in assessing risk associated with contaminants in aquatic system, further research in understanding the role that each TIE method may serve in risk assessment is also important

Identifying Organic Toxicants in Sediment Using Effect-Directed Analysis: A Combination of Bioaccessibility-Based Extraction and High-Throughput Midge Toxicity Testing

Toxicity identification evaluation (TIE) and effect-directed analysis (EDA) were integrated to diagnose toxicity drivers in a complex system, such as sediment. In TIE manipulation, XAD resin was utilized as an amending agent for characterizing organic toxicants, which also facilitate a large-volume bioaccessibility-based extraction for EDA purposes. Both raw sediments in TIE and extract fractions in EDA were tested with Chironomus dilutus for toxicity using whole-sediment testing and a high-throughput microplate assay. This allowed for a direct link between whole-sediment TIE and EDA, which strongly strengthened the characterization and identification of toxicants. Sediments amended with XAD resin, as part of the TIE, significantly reduced midge mortality compared with unamended sediments, suggesting that organics were one class of main toxicants. On the basis of bioaccessible concentrations in sediment measured by XAD extraction, a group of previously unidentified contaminants, synthetic polycyclic musks (versalide, tonalide, and galaxolide), were found to explain 32-73% of the observed toxicity in test sediments. Meanwhile, three pyrethroids contributed to an additional 17-35% of toxicity. Surprisingly, the toxicity contribution of musks and pyrethroids reached 58-442 and 56-1625%, respectively, based on total sediment concentrations measured by exhaustive extraction. This suggested that total sediment concentrations significantly overestimated toxicity and that bioavailability should be considered in toxicity identification. Identifying nontarget toxicants sheds a light on application of the integrated TIE and EDA method in defining causality in a complex environment