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Lead by the Numbers

Looking at the Flint water crisis from a different perspective.
Lead number blocks for use in typesetting. (Photo: wilhei/Pixabay)

Lead number blocks for use in typesetting. (Photo: wilhei/Pixabay)

Humans have known about the dangers of lead for millennia, yet this heavy metal continues to plague us. In fact, what's happening right now in Flint, Michigan, is just the latest example of humanity's toxic relationship with lead (though also among the most preventable). Our knowledge of lead has evolved over time, but how much do you actually know about this natural neurotoxin?

Here are some basics at a glance, presented in a numerical index depicting how this element has been able to wreak havoc through the centuries—from the expansive Roman Empire to a midsize city in the midwestern United States.

  • The atomic number of lead (Pb): 82
  • Earliest recorded lead mine (in present-day Turkey): 6500 B.C.E.
  • Year Romans began piping their water through lead conduits: 312 B.C.E.
  • Year Greek physician and poet Nikander of Colophon first described lead's damaging health effects: 200 B.C.E.
  • Number of years later Flint River water began corroding Flint's lead water pipes: 2,214
  • Number of Flint children recently exposed to lead-contaminated drinking water: 12,000
  • Minimum number of years it takes lead to fully leave the body: 10
  • Amount of money Flint hoped to save by switching to Flint River water: $5,000,000
  • Estimated maximum cost to replace residential lead pipes in Flint: $1,500,000,000
  • Average monthly water bill per household in Flint: $140
  • Average monthly water bill for the rest of U.S.: $45
  • Percentage of Flint residents who live below the poverty line: 41
  • Percentage by which the median home price in Flint fell in December 2015: 8
  • Year Thomas Midgley Jr., a General Motors employee, developed tetraethyl lead as a gasoline additive: 1921
  • Year Thomas Midgley Jr. discovered he had lead poisoning: 1923
  • Number of years later the U.S. banned lead as a gasoline additive: 63
  • Estimated tons of lead burned in gasoline in the 20th century: 7,000,000
  • Year the first clinical account of childhood lead poisoning was published: 1892
  • Number of U.S. states that have submitted recent lead poisoning data to the Centers for Disease Control and Prevention (CDC): 26
  • Number of states that don't report on lead poisoning at all: 13
  • Year the U.S. banned lead-based paints for use in housing: 1978
  • Number of American homes that still have deteriorating lead-painted walls: 38,000,000
  • Year the U.S. shuttered its largest and last lead smelter: 2013
  • Number of American homes and buildings that still receive water from pipes containing lead: 10,000,000
  • Number of years it will take to replace all of Flint's lead pipes: 15
  • Blood lead level in micrograms per deciliter (µg/dL) of the average U.S. resident in 1976: 12.8
  • Average blood lead level in 1988 (after leaded gasoline was banned): 2.8
  • Highest blood lead level recorded in Flint during the water crisis: 38
  • Blood lead level limit for children under age six that the CDC deems elevated: 5
  • Age of Flint's Gavin Walters when his blood levels tested at 6.5 µg/dL: 4
  • Blood lead level the CDC deems safe: 0
  • Decrease in IQ points for every microgram of lead in a child: 3/4
  • Total number of pencils made with lead: 0
  • Action level for lead in water in parts per billion (ppb), per the U.S. Environmental Protection Agency: 15
  • Amount of lead in water the EPA deems safe: 0
  • Highest lead ppb level found in Flint water: 158
  • Percentage of Flint homes testing at 25 ppb or higher: 10
  • Number of months Flint River water flowed through the city's lead pipes: 17
  • Percentage of Flint residents who are African American: 65
  • Estimated number of children ages one to five in the U.S. with elevated blood lead levels: 500,000
  • Odds that black children will have elevated blood lead levels compared with white children: 2:1

This story originally appeared on Earthwire as "Lead by the Numbers" and is re-published here under a Creative Commons license.