Here at TreeHugger, we report on a variety of technologies that will aid in a transition toward a more sustainable future. Seldom do these advances overlap with those being made in the arena of terrorism prevention. However, the following development seems to be one of those rare instances where the two sectors meet. Intelligent Automation Corp. has developed a system that employs Bluegill fish to detect the presence of hazardous chemicals in a water supply. The system works by diverting water samples from a river or reservoir through a small aquarium containing eight Bluegill fish. The fish, which will respond to any variation in water quality, are monitored remotely. If an inconsistency is detected, officials can be alerted 72 hours before the water reaches the public. Samples can then be taken for further analysis. The $110,000 systems are currently being used by New York and San Francisco.