If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.




Earthquakes and Bacteria, Pills and Kitty Litter

by Sarah Everts
March 19, 2007 | A version of this story appeared in Volume 85, Issue 12

Earthquakes and Bacteria

Microbes may not seem like high-profile players in earthquake prevention, but Bacillis pasteurii might beg to differ. So would Jason T. DeJong. The University of California, Davis, engineer reports in the Journal of Geotechnical & Geoenvironmental Engineering that the bug can catalyze the CEMENTATION OF SAND, a skill he hopes to exploit to stabilize buildings and levees during earthquakes.

Wherever B. pasteurii hangs out, its metabolic activity causes a local alkalinization of the soil that results in the precipitation of calcium carbonate onto sand particles. "The calcium coats the grains and locks the particles together," says DeJong. This cementing increases the soil's ability to withstand the shearing and crushing forces that occur during earthquakes.

By delivering precise amounts of calcium, microbe, and nutrients, DeJong says, the amount of cementing can be carefully controlled.

Subterranean insertion of microbes is not as esoteric as it sounds. At the recent American Association for the Advancement of Science meeting, Lisa Alvarez-Cohen from UC Berkeley pointed out that microbes that eat petroleum can be sent underground to guzzle spills from leaky subterranean tanks.

And sometimes, bugs are used for their physical skills instead of their chemical ones. Bacteria like to live in sticky films composed of proteins, carbohydrates, and DNA. Some remediation experts have tried using underground biofilms to physically block pollutants from migrating from a contaminated site into the water table, says Bill Costerton, a microbiologist at the University of Southern California.

Sometimes, these underground workhorses already live in the soil, and researchers simply squirt down nutrients to motivate their labor. Others, like the earthquake-fighting B. pasteurii, are introduced underground. DeJong argues that the environmental impact of sending microbes underground is less harmful than the alternatives, such as sending epoxy, acrylamides, and sodium silicates below ground, as is the case for current earthquake-stabilization strategies.

Credit: Istockphoto
Unused drugs: kitty litter prescription.
Credit: Istockphoto
Unused drugs: kitty litter prescription.

Pills and Kitty Litter

Speaking of sending stuff underground, Newscripts notes recent government guidelines that urge citizens to cease and desist rampant FLUSHING OF PRESCRIPTION DRUGS down the toilet.

Instead, the White House Office of National Drug Control Policy suggests combining the pills with kitty litter or coffee grounds. Newscripts simply cannot resist sharing verbatim this recommendation—one of five suggestions—for the disposal of unneeded prescriptions:

"Mix the prescription drugs with an undesirable substance, like used coffee grounds or kitty litter, and put them in impermeable, nondescript containers, such as empty cans or sealable bags, further ensuring that the drugs are not diverted or accidentally ingested by children or pets."

This counsel may read more like a non sequitur than sound advice, but here's the logic lowdown: Flushing pharmaceuticals down the toilet is increasing their concentration in wastewater, which has been disrupting the reproduction and growth of some fish. Because most landfills are lined, the Environmental Protection Agency is less concerned that drugs will leach into the water table if they are thrown into the garbage—as opposed to the direct deposit achieved by flushing.

In fact, tossing drugs into the toilet is only advised when it can further the war on drugs. The press release explains that prescription painkillers rank second after marijuana as "the nation's most prevalent illegal drug problem." Flushing is encouraged in only "a handful of cases," including the narcotic fentanyl, an analgesic opiate that often gets cut with heroin and which has "a high potential for misuse among teenagers."

Although the Office of National Drug Control Policy, the Department of Health & Human Services, and EPA seem like unusual bedfellows, Newscripts is pleased to note the government agency teamwork. But whose idea was it to prescribe kitty litter as a solution for drug disposal?

This week's column was written by Sarah Everts. Please send comments and suggestions to


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.