By Ted Zava, ZRT Laboratory
Lead is everywhere. It was commonly used in paint, gasoline, plumbing pipes, jewelry, bullets, fishing weights, glazes, and cosmetics. Some regulations are now in place to eliminate lead’s incorporation into these products, but in many cases, it is still being used. I watched a special on wine in Washington State, and the host explained why leaded crystal glasses are ideal for tasting because of the way they refract light, how thin they are, and how the rough surface helps aerate wine. I had no clue that “crystal glassware” likely contains lead. With a bit of digging I found that most wine glasses and decanters contain lead, and many are still being sold this way.
Leaded Crystal Overview
Leaded crystal glassware is known for its shimmer, clarity, weight, and strength. These properties are due to the substitution of lead for calcium in glass (this also happens in our guts). Lead allows the glass to be formed at lower temperature with fewer bubbles, making it easier to work with. The history of leaded glassware goes all the way back to a recipe for lead glaze in a 1700 BC Babylonian tablet. Leaded crystal, which contains around 24% lead, is often referred to as “crystal glassware,” just as dental fillings that consist of >50% mercury are called “silver fillings.” Not all crystal contains lead, as some glass manufacturers now use zinc and magnesium instead. After use, leaching of elements like lead from the glass surface leaves the crystal rough and pitted, allowing for better aeration of beverages when agitated.
The FDA recommended that lead crystal should not be used every day for wine consumption.
Leaching Lead from Crystal
The first thing that came to my mind when initially hearing “leaded crystal” was, “What amount of lead can be leached from the glass?” Digging into the literature, most scientific studies on leaching of lead from crystal were completed in the 1990s, around the same time the dangers of lead exposure were becoming evident. Around this time the FDA recommended that lead crystal should not be used every day for wine consumption . They also mentioned that women of childbearing age should not use leaded crystal, and that no food or drink should be stored in crystal vessels. To update you on the health risks associated with lead, it has now been established that there is no safe level of lead exposure, especially for children (children absorb 30-75% of lead ingested while adults absorb around 10%) . Highly acidic drinks such as soda, fruit juices, sweet tea, spirits, and wine will leach lead out of glass quicker than neutral or alkaline drinks. Since most people do not drink orange juice out of a crystal glass, literature searches were focused on wine and spirits.
Here are some findings from studies on lead leaching from crystal glasses and decanters:
- Port wine kept in a leaded crystal decanter had a lead concentration of 3518 µg/L after 4 months .
- Spirits stored in leaded crystal decanters long term had lead concentrations up to 21,530 µg/L .
- Sherry, port and scotch whiskey stored in leaded crystal decanters reached concentrations of 1200 µg/L after 6-8 weeks, with some reaching >1000 µg/L after a couple of days .
- Wine elutes small amounts of lead from leaded crystal in minutes .
- During a 30-min period of wine storage in leaded crystal glass, 50% of the total lead leached occurred within one minute .
- Repeat wine leaching experiments show that less lead is leached with each consecutive glass poured, and that cleaning of the glasses may expose new areas for lead to be leached .
Lead in Wine
Wine itself can be a major source of lead. The International Organization of Vine and Wine set a maximum acceptable limit of 150 µg/L lead in wine . For reference, the EPA limits lead in drinking water to a maximum of 15 µg/L . Lead contamination comes primarily from lead in soil (leaded gasoline being a big factor), fertilizers, and wine equipment . Some wine cap foils used to be made of lead, but were phased out in the 1980s. A major study showed that international wines (red and white) had average lead levels of around 34 µg/L, while wines from the United States were much lower in lead content at around 4.4 µg/L .
How Much Lead Are We Talking About?
It is difficult to determine the amount of lead you are exposed to from crystal glassware and wine. Many factors such as timing, acidity, age of leaded crystal, type of leaded crystal, how it was cleaned, how many repeated uses, how it was stored, and the wine itself will cause exposures to vary. Daily lead intake assessments from older studies cannot be compared to what we see today, as lead use has dropped significantly and has been banned from products like gasoline, paint and pipes. Not too long ago, blood lead levels <100 µg/dL were considered normal, and now levels >5 µg/dL require intervention (>2 µg/dL is being considered). The most recent guideline set by the FDA states that Interim Reference Level (IRL) for lead intake is 3 µg/day for children and 12.5 µg/day for adults . These numbers are 10x less than what it would take to reach blood lead action levels of 5 µg/dL in children and 10 µg/L in adults. From what I understand, a wine high in lead will put you over the IRL after drinking one glass, while lead from leaded crystal can significantly add to that amount. One sip of whiskey from a leaded crystal decanter can equate to months’ worth of exposure in a single day.
Reducing Lead Exposure
The primary route of lead exposure is through ingestion . Data from the National Health and Nutrition Examination Survey (NHANES) showed that the average wine drinker consumes around 1.5 glasses of wine per day . It is hard to tell the amount of lead in individual wines without laboratory testing, or the amount of lead that will be leached from leaded crystal, but there are a number of things that can help reduce lead exposure:
- Buy and use non-leaded crystal or glass. I recently emailed Riedel Glass Company about leaded crystal, and they mentioned that they have discontinued the sale of leaded crystal.
- New leaded crystal should be soaked in vinegar (very acidic) for 24 hours and rinsed thoroughly to leach as much lead as possible before use .
- Wash leaded crystal by hand with a mild detergent (neutral pH), as dishwashers erode the glass, allowing for more lead to be leached .
- If you decide to use leaded crystal, only use it for serving, never for storage . This especially holds true for decanters, which hold wine and spirits for an extended period.
- Instead of using decanters and leaded crystal to aerate wine, use an alternate aeration device that attaches to the wine bottle or glass.
- Drink wine with a meal. A study showed that lead absorption on an empty stomach was 34%, while it was only 2.3% when consumed with a meal .
- Consume domestic wines rather than international ones.
The point of this blog post is not to scare people away from drinking wine, but instead help people make smart choices about ways to reduce lead exposure. Blood lead levels, the standard for monitoring lead exposure, have dropped significantly over the last 50 years. This is a result of understanding the dangers of lead and removing it from things like gasoline, paint, and plumbing pipes. I am happy to hear that glass manufacturers are following suit. Some say lead from leaded crystal is harmless due to low exposure, but the reality is that no amount of exposure is safe. In 2016, lead exposure accounted for >60% of developmental intellectual disability according to The Institute for Health Metrics and Evaluation (IHME) . A 2018 study that tracked >14,000 adults showed that nearly 400,000 deaths/year can be attributed to lead exposure, a level 10x higher than previously estimated . There is no doubt that we are exposed to lead every day, but with knowledge of where that lead is coming from, better decisions can be made that will influence our long term health and well-being.
If you think you have been exposed to too much lead or other heavy metals, there’s a simple way to find out. Only a few drops of blood from your finger-tip or a urine collection may give you the answer. For more information about ZRT Laboratory’s dried blood spot and urine tests for lead and other heavy metals please click here.