Risk Assessment of Complex Polycyclic Aromatic Hydrocarbon Mixtures: Evaluating the Mutagenic Effects of Alkylation on Naphthalene
| Risk assessment is a scientific tool designed to address concerns about environmental contaminants, determine which hazards are the most significant, and develop a plan for remediation. The Salmonella mutagenicity assay was used to determine the possible mutagenic effects of alkylation on mutagenicity in order to improve toxic equivalency factors (TEFs). TEFs predict the toxicity of a compound based on its structure. Toxicity is often difficult to determine and validate because some diseases, such as cancers, do not surface for many years. Bioassays are used in risk assessment to evaluate the level of toxicity, while accounting for chemical interactions and allowing for metabolic activation to take place. The Salmonella mutagenicity test is a bioassay developed by Bruce Ames and others that detects carcinogens and mutagens in a plate incorporation assay. This bioassay tests for the number of revertant Salmonella typhurium TA98 colonies as a representation of the mutagenicity of the compound. Revertant colonies represent bacteria that have been mutated to no longer require histidine and biotin, which the original bacterium requires. The test chemicals were 2,6-Diisopropylnaphthalene, 1,5-Dimethylnaphthalene, 2,6-Dimethylnaphthalene, 2,3-Dimethylnaphthalene, and 2,7-Dimethylnaphthalene, and did not test positive for mutagenicity, which occurs when the number of revertant colonies is double that of the negative control over two consecutive doses. This research shows that the C2-naphthalenes did not have a mutagenic effect higher than that of the parent compound. It is possible that other alkylated Naphthalenes are more toxic, and further research needs to be done in this area. |
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