A winemaker recently asked about the impact of Arsenic found in the groundwater at her new property. There are a lot of misconceptions about Arsenic in foods and beverages, so it’s time to make some clarifications…

Arsenic can be found in water, air, soil and foods  as a naturally occurring compound, or even as a result of human activities.

In food and drink, arsenic may be present as inorganic arsenic (the most toxic form) or organic arsenic. Arsenic in groundwater is a common issue in California as well as other wine-growing regions.

There is no denying the toxicity of Arsenic. In high enough quantities it will kill you, and it has also been described as a carcinogen. According to the US Cancer Society:Exposure to high levels of arsenic has been linked to several types of cancer.

Researchers use 2 main types of studies to try to figure out if a substance or exposure causes cancer. (A substance that causes cancer or helps cancer grow is called a carcinogen.)

In studies done in the lab, animals are exposed to a substance (often in very large doses) to see if it causes tumors or other health problems. Researchers may also expose normal cells in a lab dish to the substance to see if it causes the types of changes that are seen in cancer cells. It’s not always clear if the results from these types of studies will apply to humans, but lab studies are the best way to find out if a substance could possibly cause cancer in humans before widespread exposure occurs.

Another type of study looks at cancer rates in different groups of people. Such a study might compare the cancer rate in a group exposed to a substance to the rate in a group not exposed to it, or compare it to what the expected cancer rate would be in the general population. But sometimes it can be hard to know what the results of these studies mean, because many other factors that might affect the results are hard to account for.

In most cases neither type of study provides enough evidence on its own, so researchers usually look at both lab-based and human studies when trying to figure out if something causes cancer.

Arsenic in irrigation water and certain pesticides have indeed been shown to cause an increase of arsenic levels in agricultural products. A Spanish study in 2009 indicated that irrigation with certain arsenic-bearing waters can raise the arsenic content of potatoes by as much as 35 times. Arsenic can also get into wine through the bentonite clay used as a flocculant (fining agent). The final (frequently unconsidered) path of entry into wine is incidental when using water to pitch yeast, washing barrels, washing filter press screens etc…
There has also been a lot of publicity about Arsenic in fruit juices like Apple and Pear. Many children drink a lot of juice for their body mass and start drinking the stuff at a very young age, so the FDA has recently proposed lowering the acceptable level of arsenic in fruit juice to 10 ppb, which is the same acceptable level in drinking water.
Since wine is not consumed daily in high amounts, and children don’t drink it, the current conventional thinking is that Arsenic in wine is definitely not a significant issue as compared to arsenic in drinking water.
The US limit on Arsenic in drinking water is 10 ppb. There is currently no US limit on arsenic in wine, Canada and the EU have limits of 100 ppb and 200 ppb respectively. There is currently no federal requirement to disclose arsenic levels in irrigation water on the finished product.
Malt beverages, spirits, and wines are regulated by the TTB (Alcohol and Tobacco Tax and Trade Bureau. FDA labeling and disclosure regulations apply to wines with an ABV lower than 7%, at which point they must meet nutritional labeling and other FDA requirements as codified in 21 CFR Part 101 unless they qualify for the Small Business Nutritional Labeling exception which must of course be approved by the FDA every 12 months. If the label, or advertising contains a health claim, nutritional content claim, or other nutrition information, the Small Business Nutrition Labeling Exemption does not apply. Other mandatory labeling requirements such as the ingredients statement or statement of identity are still generally required. Learn more about these rules by clicking here. Naturally, if the food product is adulterated by a contaminant, specific actions must be taken.
  • Prepared, packed, or held under conditions that are insanitary
  • Contains any poisonous or deleterious substance which may cause the food to be injurious to health
  • Contains an unapproved food additive.
This applies to all alcoholic beverages, regardless of whether the products fall into the labeling jurisdiction of FDA or not.
FDA also has acceptable arsenic levels for certain arsenic-containing additives, like Grape skin extract and Grape color extract that might be added to certain wines.
See the FDA’s position on Arsenic in Pear juice as a frame of reference: http://www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm277676.htm 
For further reference, take a look at the FDA’s release on Arsenic in rice http://www.fda.gov/Food/FoodborneIllnessContaminants/Metals/ucm319870.htm
The US Wine institute has said:  “…Arsenic is prevalent in the natural environment in air, soil and water, and in food. As an agricultural product, wines from California and throughout the world contain trace amounts of arsenic as do juices, vegetables, grains and other alcohol beverages. There is no research that shows that the amounts found in wine pose a health risk to consumers”. Some enterprising lawyers recently filed a class-action lawsuit against 28 wineries. The Wine Institute and wineries responded with the scientific facts. Read more at their Arsenic wine facts” website here.
Circling back around to the irrigation water itself, the effect of arsenic-bearing irrigation water on crops actually depends on a number of things:
  • Ferrous iron in the water can rust out into ferric iron aids in arsenic precipitation
  • Certain clays can bind to arsenic
  • Oxygenation of irrigation water can change Arsenic III to Arsenic V, which impacts absorbability
  • Certain bacteria bind almost irreversibly to certain Arsenic compounds
  • Hematite and Geothite effectively adsorb Arsenic.
  • Under the correct pH conditions, iron and sulfates can combine to form unique ferrous compounds that sequestrate Arsenic
One can comfortably conclude that irrigating vines with arsenic-bearing groundwater (especially if it also contains iron) is really not an issue at all. I would definitely NOT use water containing arsenic during any phase of the winemaking or bottling process though. Any processing water should have the arsenic completely removed.