The country that gave the world chewing gum is getting gummed up: The average square yard (meter) of Mexico City sidewalk has 70 blobs of discarded chew.
Now Mexico is responding with innovations ranging from expensive sidewalk steam-cleaners to natural chewing gum that breaks down quickly. It's even telling its citizens (gulp!) to swallow their gum.
The general in the war on discarded chewing gum is Ricardo Jaral, Mexico City's director for conservation of public spaces. He bemoans the blackened gobs that mar the newly restored 700-year-old downtown area, whose rough, porous paving stones serve as stubborn gum traps.
Jaral has purchased 10 German-designed machines that treat sidewalks with steam and chemicals, and plans a large-scale cleanup starting Feb. 1. He is also looking to launch a public-awareness campaign.
"When you finish chewing a piece of gum, you either have to put in a piece of paper and deposit it in a trash receptacle, or swallow it," Jaral said.
Not so fast, says Dr. Nick Desai, a pediatrician at the Children's Hospital at Vanderbilt in Nashville, Tennessee. He said swallowing gum isn't a good idea. It usually passes through the digestive system, but can ball up with other objects and cause an intestinal blockage.
"It's nothing to get too upset about if it happens," Desai said. "But we shouldn't make a habit of it."
Jaral shrugged off such concerns Wednesday: "I've always swallowed my gum, and it's never done me any harm."
The sticky problem involves the long-lasting, synthetic chewing gum base used since the 1940s to replace the latex-like chicle resin that ancient Mayans had long collected from the Sapodilla tree. The Mayans chewed unflavored chicle to clean their teeth.
Modern chewing gum was born in the 1860s when Mexican Gen. Antonio Lopez de Santa Anna brought some Mexican chicle to U.S. inventor Thomas Adams, who first experimented with it as a possible rubber substitute but later added flavorings and sold it as a treat.
Mexico largely forgot its natural, biodegradable gum base and wholeheartedly adopted U.S. synthetic gum. Mexicans now chew an average of 2.6 pounds (1.2 kilograms) of gum each year, half what the average American chews but still among the highest rates in Latin America. A lot of that winds up on the street.
"People just spit their gum out right on the sidewalk," marveled Paula Moran, a 32-year-old secretary. "It's ugly, and it's even worse when you step on it -- especially when it's still warm."
Of course, gobs of discarded gum are a problem around the world. Singapore once famously banned chewing gum outright to save its sidewalks, and still requires chewers to register at the pharmacy. The Rid-a-Gum company of Staten Island, New York, sells about 200 of its $3,500 cleaning machines a year.
"It's a major, major problem for malls, schools, any kind of public facility," said Rid-a-Gum owner Jack Hurley.
Some say the solution may lie in the past, with Mexico's natural chicle producers.
In the jungles of southern Mexico, Manuel Aldrete's cooperative of chicle harvesters is about to launch a line of organic chewing gums. He says his product breaks down far more quickly on park benches, streets and sidewalks.
"It dries up, breaks down and turns to dust," Aldrete said. "When it's hot it is sticky, but when it cools it dries up and peels off almost automatically."
But Jaral notes that marketing campaigns by top brands will make it hard for chicle to compete. And in any case, only about 300 tons of chicle are produced annually, a tiny fraction of the tens of thousands of tons that would be needed to supply even Mexico's domestic market.
Plus, Aldrete notes, the "environmentally conscious consumers" who buy organic gum probably aren't the same people spitting their chews onto the sidewalk.
"They're the kind who are probably going to find a garbage can and deposit it in the one labeled 'organic waste,"' he said.