Should I buy a Prius?

Hey Mr. Green,

I keep hearing hype about how hybrid cars are so much better for the environment, yet I also hear that the process to make the batteries for them is very toxic. If so, the Toyota Prius isn't a very green car, so I won't be wasting the extra cash to damage the planet. Is this a wise choice?

--Jacque in Missoula, Montana

The fuss about Prius batteries is because they're made of nickel. Thirty years ago, Canada's nickel-mining industry was particularly toxic, but our northerly neighbors have since cleaned up their mining mess. Only a fraction of the world's nickel is used for batteries, and those made for Priuses (Prii?) are recyclable. For a fuller refutation of this and other myths about the Prius, go to tinyurl.com/mrgreenprius.

However, don't rush out to buy a $22,000 Prius unless you have unlimited funds. You might net greater energy savings by purchasing a cheaper but still-efficient car--like a Toyota Yaris--and investing the money you save in less-sexy energy-conservation measures like replacing your furnace, upgrading your insulation, and installing fluorescent lights, programmable thermostats, an Energy Star fridge, and so on. Sure, the furnace and insulation won't sit in your driveway and flaunt your environmental rectitude. But they could reduce more emissions and save more money in the long run. Consider your energy habits and where you live, and do a basic energy inventory using some simple math.

Say you drive 10,000 miles per year, mostly on the highway. The Prius is rated at 45 miles per gallon (highway), so it'll burn 222 gallons a year. If gas is $2 per gallon, you'll pay $444 per year for fuel. The efficient little Yaris gets 35 mpg, so it'll burn 286 gallons annually, costing you $572. The Prius, then, will save 64 gallons and $128 per year and emit 1,250 fewer pounds of carbon dioxide. But its base price is almost ten grand more than the Yaris.

By choosing the Yaris over the Prius, you'll have an extra $10,000 to spend on planet-preserving home upgrades that will save more energy than the Prius. Of course, if your home energy use is far less than average but you drive far more--or if gas prices climb back to the $5-per-gallon range--the equation changes.

What To Do With Old Meds

Hey Mr. Green,

What's the best way to deal with leftover prescription medications?

--Paul in Delmar, New York

Dispose of unused medications in your trash can rather than flushing them down the toilet or sink. Sewage-treatment plants can't remove all chemicals, and when pharmaceuticals are in the outflow (whether dumped in whole or after they've passed through the body), they harm marine life. Male fish, for example, are becoming female because of drug contaminants in waterways.

Researchers in Colorado, to cite one instance, found characteristics of both sexes in many individual white suckers; in Boulder Creek, females outnumbered males five to one, and half the males also had female organs--not because of willing transgender tendencies, but because of hormones in the water.

To be hypercautious, or if your neighbors are dope fiends who'll rummage through trash and ingest any meds they find, follow these procedures recommended by the EPA: (1) Keep medicine in its original container, scratching out the patient's name. (2) Check whether your community offers a prescription-drug disposal program--many do. (3) Before discarding them, modify drugs to discourage consumption by adding a small amount of liquid to pills, and adding salt, charcoal, or spices to liquids. (4) Seal the container shut with strong tape. (5) Place it in a nontransparent bag (don't hide it in food products). (6) Discard it as close to the scheduled garbage pickup time as possible.