“We produce over 70,000 chemicals that end up in freshwater ecosystems,” said Chris Vulpe, PhD, title at the University of California, Berkeley. “Worse, we don’t know the toxicity or potential environmental impact for the vast majority of these chemicals.”

Ultimate Goal

According to Dr. Vulpe, current toxicity tests rely on expensive, slow, whole animal toxicity studies on many species, including fish. The current approach, he adds, is impractical and requires the use of whole animals to determine risks related to new and existing chemicals in fresh water ecosystems. He and his co-researchers have a better idea. “We intend to use cellular, high content cytotoxicity assays using the fathead minnow and the rainbow trout, eco-indicator and sentinel species for freshwater ecosystems,” explained Dr. Vulpe, pointing out that just cells, not the whole fish, will be used for testing. “But, first, we have to test available high content screening assays designed for mammals for their suitability for fish cell lines.” The scientists will test the suitability of inexpensive and rapid assays for evaluating 320 chemicals . Finally, established cell lines for the fathead minnow and the rainbow trout will be tested for response to a wide range of toxicants. Importantly, these same chemicals have been tested by the EPA in mammalian cells so we will be able to compare the results in fish and mammals. We have a material transfer agreement in place with the EPA to carry out this work and compare our resutls. “We believe that our study will provide the first comprehensive analysis of high content screening in ecoindicator species using fish cell lines rather than whole animals,” said Dr. Vulpe. “The approach could radically transform ecotoxicity testing and provide rapid and inexpensive testing for toxic chemicals in the freshwater ecosystem.” Testing will be carried out at the Berkeley Screening Center (http://bsc.berkeley.edu/) capable of carrying out high throughput High Content Screening. To complete their first objective, a phase one study lasting three months will test the fathead minnow cell line with five to 10 chemicals. Phase two will test the rainbow trout cells with the same chemicals over three months. In phase three, they will test additional assays with the same two cell lines. The second objective will, in phase one, test the 320 chemicals in a high throughput format using both cell lines over a nine-month period. Phase two of the second objective will evaluate the data, compare the results to those obtained in mammalian cells and prepare it for publication. “This approach could significantly improve our capability to protect our aquatic ecosystems by making an assessment of the tens of thousands of chemicals for which no information is currently available,” concluded Dr. Vulpe. “Of course, the cell-based approach could also dramatically reduce the use of animals for testing chemical toxicity.”