Articles

Cities Protect Drinking Water Using Fish

Bluegills assess contaminants in water via an aquatic monitoring system.

by / January 18, 2009
Cities Use Fish to Protect Drinking Water Stock photo

San Francisco, New York City and Washington, D.C., use technology that's intertwined with nature to protect their drinking water. By coughing, swimming at different depths in an aquarium and changing their movements and breathing, bluegills -- a small fish from the sunfish family -- set off an elaborate monitoring system that shows city officials when contaminants are present.

The bluegills are part of an aquatic monitoring system that alerts officials if there's anything foul in the drinking water. The fish react to toxins in the water, and their reactions -- such as bubbles from their coughing -- set off sensors to test the water for contaminants. The fish can detect toxic materials such as metals, cyanide, organic solvents and pesticides.

"We have a probe on there that looks at pH, temperature, dissolved oxygen -- those sorts of things," said Bill Lawler, vice president of sales and marketing for Intelligent Automation Corp. (IAC) -- recently acquired by Honeywell -- the company involved in the system's creation. "We want to make sure there are no other things in the water causing the fish to react."

 

And So It Began

Scientists at the U.S. Army Center for Environmental Health Research in Fort Detrick, Md., are known for doing much of the basic research on the bluegill, Lawler said.

"They were the ones who started some of the early work monitoring water using bluegills. It was a real-time kind of thing where they would monitor and watch the reactions of the fish."

But even as early as 100 B.C., bluegills were placed in moats to monitor water, Lawler said, adding that he thinks a fair amount of municipalities use a more simplistic version of this technology. "They do it in a sense, not electronically monitoring," he said. "In other words, if the fish floats, the water's bad."

Tom Shedd, a research aquatic biologist at the Center for Environmental Health Research, and one of the scientists who helped create this system, noted the bluegill's history.

"Historically the fish have been shown to be a good indicator of toxicity in the water," he said, "but the problem was how to digest that information, put it all together and get rapid information out."

That's where IAC comes into play.

The technology that San Francisco, New York, Fort Detrick and Washington, D.C., use today -- the IAC 1090 Intelligent Aquatic BioMonitoring System -- was developed in partnership with the U.S. Army.

In October 2001, the Army began using the technology at Fort Detrick. That same year, IAC decided to commercialize it. The Army has a patent on the technology and IAC purchased the license.

It wasn't until spring 2004 that Fort Detrick had an incident. "We never really found the issue," Shedd said, "but the fish responded very aggressively, and we reacted to that appropriately."

Since then, there have been no incidents, but with the decline in the economy, Shedd said people will likely take more shortcuts with chemicals, increasing the chances of water contamination.

"It's just Tom Shedd talking, but with the downturn in the economy, a lot of people don't do the right thing with toxic, industrial chemicals," he said. "They have a tendency to find the easiest path to get rid of them -- an out-of-sight, out-of-mind kind of thing. As the economy turns down, there just isn't enough money to accomplish some of the environmentally relevant activities that you should be doing. I'm not saying it's a bad world out there, but there are some things folks can justify based on where they are in their current financial situation."

IAC worked with the Army by taking its concept and automating it through the IAC software and some electronics experts, to

make the system more portable and less expensive, Lawler said.

To develop the software for the biomonitoring system, IAC developed a software model of a normal fish and how it reacts, and made that robust enough to account for the variations in water and fish, Lawler said. That software was then run in real time against the real fish and their reactions.

 

How It Works

The IAC 1090 Intelligent Aquatic BioMonitoring System works on the same principle as an electrocardiogram (EKG), Lawler said. "There are noncontact sensors in the water, so as the fish swim, breathe and cough, their movements are detected by the noncontact sensors," he said, adding that those sensors are the same type of material found on an EKG machine. "In other words, any tiny movements your body produces or the fish produce generate a very tiny electrical signal that is detected by the sensors and then amplified."

The premise is that the system's users have a broadband detection system in real time, Shedd said. "So what you're monitoring is the fish's ability to aspire -- the respiration of the fish, if you want to call it that," he said. "The changes in their breathing patterns are indicative of changes in their water, so it's very helpful in detecting poisons in the water."

The time it takes for the fish to respond after a contaminant hits the water is about one hour, he said, adding that the "lethal concentration 50 parameter" is also a factor. "It's a lethal concentration of material that causes 50 percent mortality," Shedd said. "Let's say someone put an organic material in the water of X concentration where 50 percent of your fish would die in four days. At that concentration of material, the system picks most substances up within an hour, so you have a window of opportunity to take some type of action."

Eight bluegills are "online" at any one time, Lawler said, adding that's the smallest statistically significant sample that can be used. Those fish stay on duty for two to three weeks, and are then rotated with eight new fish from another aquarium where the fish get to rest.

"We're told by the scientists that they can go significantly longer, like eight to 10 weeks," he said, "but we run them only two to three, tops."

Water coming in to the bluegills for testing runs through a system -- a series of pumps and thermo-chillers -- to keep the temperature constant so that's not a variable that affects them. "We want everything the same so they're not being disturbed by any outside influences other than just the water," Lawler said. "They get very sensitive to that."

At least six of the eight fish must change their behavior to cause alarm about contamination, he said. "If one or two fish are having a bad day, it's not going to cause an alarm," Lawler said. "And that does happen, so you want to make sure."

And no one monitors the fish or the system in-person -- when six of those eight fish start acting strangely, the system sends an alarm. "You want it to be reliable and accurate, and nobody really has time or can afford to pay someone to sit there and watch the fish all the time," Lawler said. "So this system was designed basically to run an automatic, powerful, reliable and accurate, early warning capability."

 

What's in the Water?

The bluegills can detect any type of toxicity, but Lawler said the trick with toxicity is that there are so many possible variations.

"The bluegill has such a broad detection range, he said. "And these compounds are forming and mutating; depending on the water, you can get a wide variety of toxic material."

The system's cost depends on different factors -- it can handle everything from raw resource water to chlorinated water. Those types of water, however, must be treated because bluegills are freshwater fish.

"Chlorinated water is toxic to fish, but we have a device that can actually dechlorinate it without removing the toxins so the fish can still monitor treated water," Lawler said. "A few other things come with that, but the basic system itself is less than about $60,000."

So far, the system has been effective, he said, though there have been no big threats against the drinking water supplies.

"One of the systems at Fort Detrick, for example, alerted -- they think someone cleaned a pesticide truck in the river," Lawler said. "And it did actually end up killing all the fish, but it sent out an alarm before that happened."

The city shut the water off, but fish at the facility monitor both the treated and the raw water. The fish monitoring the raw water sent out the alarm, but the fish monitoring the treated water were fine, Lawler said. A sand filter in place didn't let the contaminate pass through to the bluegills monitoring the treated water.

The city of Fredericksburg, Va., also shut off its water supply as a precaution because it's only about 100 yards down from the water intake at Fort Detrick.

With bluegills protecting drinking water on each coast, what's next for the freshwater species?

"Some of those agro issues you see out there -- I think we have had some interest in those sectors," Lawler said, "which might be a way to protect the water that goes and treats our food supply."