The Hazards of Lead
L-E-A-D. What is it? Oh, everyone knows. Or do we? As a child, your first conscious awareness of lead was probably the black substance found in pencils. But soon enough you considered yourself learned when you came to find out that ''lead'' in pencils is really just graphite (actually it is a graphite and clay mixture). Later you became thoroughly confused when you learned that graphite and diamond have the same chemical formula, yet are so different visually and economically. To clarify some of these confusions consider that lead was used as a line writing tool all the way back to the Egyptians. But when graphite became the preferred writing filament in the mid-16th century, and chemistry had not yet sufficient discriminated graphite from lead (that was to come in 1779 by K.W. Scheele), people started calling graphite filled pencils, ''leaded.'' Unfortunately, the confusion surrounding lead goes well beyond its associations with the pencil. A closer look at lead reveals some much more important issues as well.
Your first real contact with lead occurred before you used your first pencil or could even spell it. It is an element that entered your body when you were just an embryo and from that point on has affected you and your children in ways that you probably didn't even realize. For this reason, lead definitely deserves a closer look.
The use of lead throughout human history, from its discovery in Turkey some 8,000 years ago, is a story that could fill many book volumes. And from the earliest beginning of its use, it has been strongly associated with human suffering. Many have speculated that the Roman Empire fell in part due to the influences of lead poisoning largely because its wide use in items including face powder, paint, birth control (spermicide), wine preservative, and most importantly, plumbing pipes. In modern times, lead and lead derivatives can be found in paints, pipes, and gasoline. In fact, most homes in Galesburg likely have lead pipes or lead paint somewhere on their property and all the soil in the area still contains traces of lead emitted via vehicle exhaust, despite that the primary phaseout of leaded gasoline in the United States took place in 1986.
So lead is clearly present, but how is it so destructive and insidious? Surprisingly, in its elemental form (written Pb), lead isn't poisonous to humans! However, when lead comes in compound form (that is, when it reacts with another chemical) and becomes oxidized or dissolves, it can be deadly. (For the purposes of simplicity, for the remainder of this essay, ''lead'' will used in its most general sense, which includes all of the compounds in which it is commonly found.) Lead, which the human body has a hard time differentiating from calcium, disrupts bodily functions and accumulates in the bones and teeth. For example, lead, upon entering the bloodstream, is known to interfere with the production of hemaglobin and therefore in moderate...