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USING QSAR AND SAR TO PREDICT THE TOXICITY AND DEGRADABILITY OF CHEMICALS IN SEDIMENTS AND WATER: AN EVALUATION USING QUADRICYCLANE AND IT'S ANALOGS
Citation:
SchubauerBerigan, J, K. B. Lodge, AND S. Basak. USING QSAR AND SAR TO PREDICT THE TOXICITY AND DEGRADABILITY OF CHEMICALS IN SEDIMENTS AND WATER: AN EVALUATION USING QUADRICYCLANE AND IT'S ANALOGS. Presented at International Conference on Contaminated Soils, Sediments and Water, University of Massachusetts, Amherst, MA, 10/1/2001.
Description:
The NRC has examined the availability of toxicity endpoints for industrial chemicals and concluded that many of these chemicals lack even minimum testing. One way of carrying out risk assessments of chemicals having insufficient experimental data is by using Quantitative Structure Activity relationship (QSAR) models and SARs. In this study we examined the toxicity and degradability of Quadricyclane and six of its analogs selected using Quantitative Molecular Similarity Analysis (QMSA) to evaluate the usefulness of this approach for chemical risk assessment. The degradability of these chemicals was examined in spiked water ane sediments collected from a freshwater and marine location, under a variety of test conditions (abiotic, biotic, aerobic and anaerobic). The sediments water used in the experiments were thoroughly characterized for their physical, chemical and biological properties (e.g., salinity, OM content, nutrients, bacterial numbers, etc.) The toxicity of the chemicals was examined using a number methods of commonly used in the literature for this purpose (BODs, Microbial Plate Counts, and Microtox). In addition, a novel new approach was developed using Biolog Microplates to examine the effect of these chemicals on substrate utilization patterns of natural microbial communities from the sampling locations. Results of the studies indicated that large fraction of the degradation of Quadricyclane and its analogs occurred primarily abiotically. The rate of chemical degradation and toxicity was influenced by the collection site of the exposure matrix. The chemicals tested resulted in altered microbial substrate utilization patterns compared with natural unexposed communities. The results of the degradability and toxicity studies verified the usefulness of QSAR, SARs and QMSA for risk assessments of chemicals having insufficient experimental data.