News & Politics » Straight Dope

The Straight Dope

by

comment

Paper or plastic? --Nigel in D.C.

Seems like such a simple question; wish I could give you a simple answer. Unfortunately, as happens so often these days, all I can say is: it depends.

Q: On what?

A: Well, for starters, on whether you're asking me while I'm in the checkout line or the john.

Q: The checkout line, of course.

A: It still depends. The knee-jerk answer given by the 50-ways-to-save-the-earth crowd is that paper grocery bags are better than plastic because paper is renewable and biodegradable. But the plastics industry and others point out that (a) paper bags are often made from virgin timber, which if not exactly nonrenewable is not easily replaced; (b) papermaking typically requires toxic chemicals and generates pollutants; (c) the sheer mass of material required for a given quantity of bags is much greater for paper than plastic, and paper for that reason requires more resources for materials handling throughout its life cycle, from manufacturing, transportation, and storage to disposal; and (d) modern landfills are designed so that little decay occurs, which minimizes the importance of biodegradability.

To be sure, manufacturing plastic bags imposes costs of its own. But never mind that. Framing the answer in this way suggests you've already made a fatal assumption.

Q: Which is?

A: That whichever bag you get is going to be discarded immediately. The whole point of recycling is to reuse things rather than toss them out. Purists say you should bring your own cloth tote bags rather than use the store-supplied ones--easier said than done if you're buying the week's groceries for a big family. If, like most people, you use the store's bags, the real question is which is easier for you to reuse, and the answer depends on your personal situation. City guy that I am, I need some of both: paper bags that I can fill with cans and leave out in the alley for the aluminum scavengers, and plastic so I can pick up the deposits my neighbors' dogs constantly leave on my lawn.

DO FISH FART?

Richard J. Krejsa, professor emeritus at California Polytechnic State University, writes, "Your November 10 article is full of gas! [Long rant omitted, in which Krejsa disputes Cecil's claim that little research has been done on fish farts.] In 1959, as an ichthyological graduate student, I was in charge of a research project on herring [which involved tranquilizing the fish and then tagging them]. My job...was to determine a proper dosage of fish tranquilizer that would not kill fish outright but would quiet them down slowly and allow them swift recovery....Over the course of two months I observed herring behavior in my seawater lab aquaria and experimentally narrowed down dosages to an optimum range. As the narcotic effect occurred, the herring relaxed and began to lose their upright orientation, and gas bubbles were released from what appeared to be the anus! I immediately thought: 'I'm observing a phenomenon never previously reported in the ichthyological literature: herring farts!'

"I then dissected some herring specimens and discovered that, in addition to the presence of a pneumatic duct, herring had a small posterior extension of the air bladder that opens alongside the anal opening. I searched the early herring literature and discovered that several members of the herring family, Clupeidae, also have such an opening. The gas release appeared to be farts, but technically it wasn't. In a previous summer I had worked on a herring purse seiner and discovered while attempting to encircle a large school of herring with a purse seine that the herring may 'sound,' i.e., begin swimming downward and deeply in order to escape the encircling wall of netting....The primary visual cue that a [purse-seine boat] captain uses to determine that a herring school has sounded is the enormous cloud of bubbles that appears at the surface. It means that somehow the herring, in unison, have sent up a giant, bubbly (noisy?), silver 'fart' that confuses the predator, in this case human fishermen, and the school survives another day!...

"I wrote this up in my summer research report to the U.S. Fish & Wildlife Service and...became known as the guy who discovered fish farts! Indeed...one of my colleagues, Dr. Harold Harvey, named the excretory expulsion of swim-bladder gases by young salmon in my honor. He called it 'exkrejsiation'!"

Proves what I've always said: No matter how bizarre the question, there's someone somewhere who's researched the answer. All an aspiring know-it-all has to do is find that guy and grill him--and while he's at it, maybe a couple fish.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

Add a comment