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1 .This is Scientific American's 60-Second Science. I'm Karen Hopkin. This'll just take a minute.
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2 .When you think about air pollution, you may picture smokestacks belching out noxious black clouds or the gas-guzzling SUVs crowding the highways.
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3 .But different cultures found different ways to foul the atmosphere long before the industrial revolution.
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4 .The latest example of preindustrial pollution comes from Peru almost half a millennium ago.
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5 .To get a read on what humans have been ejecting into the air, researchers pulled ice cores from Quelccaya, a glacier high in the Andes.
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6 .The samples provide an annual archive of elements that have been circulating in the atmosphere stretching back to the year 793.
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7 .Analyzing the core, the researchers found that prior to about 1532 the ice harbored only a sprinkling of dust and ash, remnants of the occasional volcanic eruption.
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8 .But at about the 1540 mark, corresponding with the start of colonial mining and metallurgy, the cores suddenly contain chromium, molybdenum, antimony, and lead.
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9 .The finding is in the Proceedings of the National Academy of Sciences.
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10 .Of course, these waste products are a proverbial drop in the bucket compared to the toxins we put out today.
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11 .Because we've developed ways to pollute that people back then could have only dreamed of.
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12 .Thanks for the minute, for Scientific American's 60-Second Science. I'm Karen Hopkin.
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