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digging up plastic water bottles that are thousands of years old. These bottles aren't clear, and they don't have labels.They're pitch black—made by indigenous tribes who coated large, woven bulbs with a tar-like substance called bitumen."I became uncomfortably curious, and not sure how strongly I should consider this as a factor in some of the changes I had seen in the skeletal record," she says.After getting her Ph D and a job at the Smithsonian, she took the opportunity to explore that curiosity.Transporting water—in bottles, through pipes—has always been tricky business.It's not just a matter of using a material that doesn't leak. Given enough time, and the right p H, it will dissolve just about anything.
This is bitumen, and for thousands of years Native Americans in this region had used it to build boats, make weapons, and craft water bottles."The earliest evidence we have of of people on these islands comes from about 13,000 years ago." One of the outstanding mysteries about these island-dwelling tribes—collectively called the Chumash—is why their overall health began to decline, beginning around 5,000 years ago.Skeletal remains dating back to that time start to exhibit poor bone quality, reduced stature, smaller skulls, and bad teeth. Some researchers posit that malnutrition, poor sanitation, infectious disease, and lack of resources brought about by increased population on the islands might be the culprits. On certain beaches in Southern California, you have to watch your step to avoid stumbling on a nasty little ball of tar.You have to melt them together, but you don't place the abalone directly onto the fire.
Instead, you roast some pebbles in a fire until they are piping hot.
For scientific accuracy, Smith collected his materials from the islands—the plants for the basket, the pitch, the bitumen, even the pebbles. Oz-ified society knows, plastic bottles pollute whatever is put in them.