Small Fish for a Large Task

David Hinton Takes His Medaka West to Monitor California's Drinking Water

By Monte Basgall

David Hinton, the Nicholas Professor of Environmental Quality, is sending some of his Nicholas School-bred medaka to urbanized Orange County in Southern California. There the guppy-like Japanese fish will be evaluated for becoming living sentinels. Their apparent health may provide evidence that Orange’s drinking water is safe. Alternatively, any signs of lesions on or in their diminutive bodies may hint of unseen toxic agents.

Measuring only 1 to 2 inches long in adulthood and available in both standard and transparent forms, medaka have joined the ranks of model animals that scientists are evaluating as biomonitors of toxic dangers. Because fish eat, drink, breathe and live continuously in water, they bioaccumulate water-borne contaminants. Their use mimics roles live canaries once played in sensing for poisonous coal mine gases.

   “These fish will be telling us whether their continuous residence in that water is interfering with their reproduction and normal development or is associated with cancer formation,” Hinton says in an interview in his Nicholas School office and laboratory.

   In what he predicts may be an emerging trend elsewhere in the United States, Orange County—which includes cities like Anaheim, Santa Ana, Fullerton and Newport Beach— reclaims about 75 percent of its drinking water by treating previously used wastewater. Recycling is necessary in places where “it doesn’t rain from April until October or November,” he says. The tug of war over who gets the water is a constant refrain there, which Hinton observed first-hand during previous years as a University of California- Davis aquatic toxicologist.

   Hinton now teaches a course that evaluates “lessons from California’s watershed management” for students in the Nicholas School’s master of environmental management program. In his interview, he describes how southern California depends on winter mountain snowpacks for much of the water it will need over the following year.

   That journey to Orange County’s spigots begins when the snow melts and collects in massive reservoirs. From there much of the runoff flows down to the San Joaquin Delta and then the Sacramento River, where huge pumps push it south towards waiting and thirsty cities and towns. But before it reaches those pumps, agricultural interests in California’s Central Valley lie in wait to tap a substantial portion of the flow.

  “There are real competing interests,” Hinton says from experience. “There are farmers who want to continue to get their portion of the water. There are industries. Then there are water treatment plants positioned at the cities that have to clean up the water before their constituencies can drink it.”

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