I found what follows on this website http://www.divinecaroline.com/22355/49745-landfill--trash-really-last-
Glass Bottle—One Million Years
Okay, we don’t really know whether a glass bottle takes a million years, two million years, or a million years and one day to degrade since no one has been monitoring them for that long. But suffice it to say, when a glass bottle isn’t recycled, it sticks around for a really, really long time. Glass is primarily of composed of silica—the same material as sand—and doesn’t break down even under the harshest environments.
Plastic Bags—Unknown, Possibly 500+ Years
Plastic bags also have a hard time decomposing; estimates range from ten to twenty years when exposed to air to 500–1,000 years in a landfill. Since microbes don’t recognize polyethylene—the major component of plastic bags—as food, breakdown rates by this means in landfills is virtually nil. Though plastic bags can photodegrade, sunlight in landfills is scarce. Made with petroleum and rarely recycled, many cities have banned them in order to curb consumption and prevent their long-lasting presence in litter
Plastic Beverage Bottles—Unknown, Possible 500+ years
Bottles face the same problem as plastic bags. Most soda and water bottles are composed of polyethylene terephthalate (PET), a petroleum-based product that tends to last a long time in a landfill. Even newer bottles that claim to be biodegradable or photodegradable may take much longer than advertised. According to the Air and Waste Association, biodegradable plastics made with the addition of starch may just simply disintegrate into smaller non-degradable pieces: they don’t break down; they break up.
Aluminum Can—Eighty to 200 Years
According to the Container Recycling Institute, we sent 55 billion aluminum cans to the landfills in 2004, an amount that has increased by 760 percent since 1972.
Cigarette Butt—One to Five Years
The Ocean Conservancy found that during coastal cleanups, cigarette filters and butts were the number one source of litter. While certainly they’re better off in a landfill than underfoot at the shore, their composition makes them particularly resistant to breakdown both in nature and in a landfill. Though the filters look like cotton, almost all are made of cellulose acetate, which is slow to degrade.
Newspaper—Two to Four Weeks or Longer
Paper, including newspaper, seems like one of those items that although recyclable, would also break down quite nicely when mixed in a landfill. Theoretically it can, but because microbial decomposition is so stifled in landfills, paper takes much longer to decompose there than under normal conditions. Or so discovered William Rathje, a professor of archeology at the University of Arizona, who started the Garbage Project—digging through landfills to find clues about consumer behavior. While there, his team found legible newspapers more than fifteen years old, indicating decomposition in landfills doesn’t occur as it would in a compost heap. They also discovered that newspapers made up the largest single item by weight and volume in the landfills studied.
Apple Core—One to Two Months or Longer
If tossed in a composting bin or outside, an apple core might take weeks or months to break down. However, the Garbage Project discovered easily identifiable food and yard waste that were years old. They estimate that food in landfills does degrade, but at a very slow rate—about 50 percent every twenty years. Even yard waste, by definition biodegradable, was found intact years later.
I think that is enough to make most of stop for a minute and think. However that only talks about how long it takes something we throw away to actually degrade. Now think about the costs of having a truck come to your house pick it up, take it back to the landfill, etc. How much air pollution does the truck create? What happens to the truck tires, oil, etc when they get changed out? How much of our waste can the landfill handle, once its full where will more land be found to pile trash on? Down the street from your house?