The Romans had a sweet tooth, but didn鈥檛 know about sugar. So they boiled down grape juice to make a sweet syrup called 鈥渟apa鈥� which they added to wine, as well as to various foods. The acidic juices were boiled in lead vessels because experience had shown that this enhanced the sweetness of the product. Of course, the chemical nuances of the procedure were unknown to the Romans, but we now understand that acids can readily leach lead from containers. Indeed, lead acetate is sometimes referred to as 鈥渟ugar of lead.鈥�
One of the amazing features of lead is its extreme toxicity. Regular intake in the milligram range can have catastrophic consequences. Stomach cramps, weakness, headaches, irritability, loss of appetite, anemia, high blood pressure and kidney problems are classic symptoms of lead poisoning. These are nasty enough, but perhaps the most insidious aspect of lead is that it can be devastating over the long term at intakes which are too low to cause overt symptoms. Mental confusion and impairment of judgement have been connected with chronic low-level exposure. The Roman ruling classes would have been the most affected because they drank more sweetened wine, usually from lead-based pewter mugs and had access to water that was delivered through lead pipes. Believe it or not, the components of the fall of the Roman Empire (namely Caligula鈥檚 orgies, poor military decisions by Roman Emperors, and Nero鈥檚 fiddling while Rome burned), have all been linked with exposure to lead. While this may sound somewhat fanciful, there is actually archeological evidence to bolster this lead-poisoning theory.
The toxicity of lead is partly due to its chemical resemblance to calcium. Calcium is essential for a myriad of biochemical reactions and of course is one of the main building blocks of bone. When lead is present in the system, our bodies can mistake it for calcium and incorporate it into bone where it can be readily detected by x-rays. Remember how Superman鈥檚 x-ray vision was always stymied by lead shields? Archeologists have x-rayed some ancient Roman skeletons and have indeed found abnormal levels of lead. And abnormal levels of lead may also have set the sun on the British Empire. George III was king of Britain during the American Revolution and some historians have suggested that it was his inept handling of the situation that led to the loss of the Colonies. George was not only inept, he was close to being insane. His madness has been widely attributed to porphyria, a disease of faulty hemoglobin production. It is usually an inherited condition, often characterized by purple urine, which George was known to produce. But lead poisoning can also cause similar symptoms. And how was George exposed to lead? Being of German ancestry, he loved sauerkraut. His cooks prepared it in lead pots, almost exclusively for the King. Sauerkraut was not a delicacy favored by the royal subjects, so conceivably, only George suffered the serious effects of lead poisoning.
Whether lead played a part in the downfall of the Roman and British Empires may be a question more of interest to academics, but when you look at whether our own lives are being attacked by this stealthy intruder is a question of great practical importance. Peeling paint and crumbling walls may not sound like weapons of war, but they can mount a pretty effective assault on health. Lead carbonate was the main white pigment used in paint up to about 1950 and was still in common use until 1980 when it was eventually phased out. Scientists had become concerned because lead from paint was finding its way into people鈥檚 bodies, particularly young children in poor neighborhoods who had a fondness for putting flakes of peeling paint into their mouths. As it turns out, one milligram of lead from paint, ingested daily, can cause poisoning. A window sill often accumulates paint dust just from the normal up and down movement of the window frame. Touching this and then sucking on a thumb can lead to the ingestion of dangerous amounts of lead. And here is the really scary finding. The poisoning may not be immediately apparent. Indeed, it may show up only years later as aggressive behavior, learning disabilities, poor speech articulation, hyperactivity or a subtle drop in IQ!
Millions of children in North America have high blood levels of lead and they do not necessarily live in old dilapidated buildings. Some parents have inadvertently made their children sick by carrying out home renovations which generated lead-laden dust. Although drugs are available to rid the blood of lead, that which has deposited in the brain remains forever, permanently impairing mental performance. And it is not only children who can be affected. One of my colleagues, ironically an analytical chemist, experienced this tragic scenario first-hand. Dust from renovations in his stately old residential building drifted into his apartment. causing both his wife and mother-in-law to experience symptoms that were consistent with lead toxicity. The lead-filled dust became a life-changing nightmare.
We have to take lead pollution seriously. Renovations in houses which may have lead paint must be carried out by contractors who have proper training and equipment. A screening program for lead in the blood of children in underprivileged areas may be the best way to find problem homes. Massive federal funding will be needed to remove the paint and, in some cases, even the soil around the house which may harbor paint chips. Children鈥檚 nutritional status will also have to be evaluated. Adequate calcium and vitamin C intake can significantly reduce lead absorption, but it is precisely these nutrients that poor children lack. Drinking water should also be monitored and a filter used if lead levels are above 10 parts per billion. Thanks to modern chemistry, there are a number of ways to monitor lead in our environment and techniques to deal with the problem appropriately.
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