Lead is toxic to all organisms in minute quantities, debilitating fundamental biochemical processes. In humans, it can affect every organ system. The effects on cognitive ability are especially profound.
While volcanoes spill some lead in their earth-shattering eruptions, humans have made lead an environmental element as it never was before. Lead is exemplary of man’s depravity and idiotic carelessness.
That lead is gravely poisonous was known to the ancients. Yet, until the mid-20th century, moderns imagined lead to be harmful only if ingested in large quantities, and its utility was so alluring as to overcome safety concerns.
Lead is easy to extract from the ground. It is malleable and resistant to corrosion: qualities that made lead the material of choice for everything from municipal water pipes to food tins to jewelry. Lead makes paints shiny and more durable and brightens paint colors. So lead was added to the arsenal of industrialized compounds to be strewn hither and yon.
The widespread addition of lead into petrol as an anti-knock compound spewed the toxin into the air, diffusing it worldwide. Even the polar ice caps are now imbrued with lead.
Lead’s inclusion in paints and many other products carelessly spread it around. Lead is still used in paints and petrol in Africa and many other places around the world. In Pakistan, paints labeled “lead-free” were found to have the highest levels of lead.
Despite the grievous health danger, the level of lead in the environment is only sporadically measured.
Unlike some compounds, lead does not quickly leach out of the soil. Plants uptake and retain lead in their roots. The lead that does vacate the soil typically makes its way into groundwater.