Herself's Houston Garden

Conservation through cultivation

Antibiotics in water might be removed by grass




Not only might grass do an excellent job of removing antibiotics from our water supplies but the tetracycline fed grass grew much faster.

What goes in must come out, and when animals are given antibiotics, they can find their way into the water supply. Now, a Michigan Tech senior has identified one way to sop them up.

Working with Rupali Datta, an associate professor of biological sciences, Smith designed an experiment using sterile vetiver grass to address the issue. Vetiver is a native of India often grown in artificial wetlands to cleanse wastewater. It is both vigorous and noninvasive, posing little risk to indigenous plants. It’s also been used to clean up some tough customers, including TNT.

Smith grew vetiver hydroponically in a greenhouse, exposing the plants to various concentrations of tetracycline and monensin, two antibiotics commonly used to treat dairy cattle. “We wanted to see if the vetiver would uptake them, because if you give these antibiotics to cows, 70 percent is excreted in active form,” Smith says. “We worry about them leaching into the groundwater, getting into drinking water and compounding the problem of antibiotic resistance.”

At the end of the 12-week study, all of the tetracycline and 95.5 percent of the monensin had disappeared from the hydroponic solution. Tests showed that the vetiver had taken and metabolized both drugs up into the plant tissue. The results are preliminary, says Smith, but they show that vetiver holds promise for remediating antibiotics in wastewater.

Smith also recorded a peculiar side effect. “The plants in the tetracycline solution grew faster, much faster than the controls,” she says. “The plans in monensin grew somewhat faster, but not as much.”

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