Gradual accumulation of contaminants may be hazardous

The red and white wines imported from a number of European countries contain seven heavy metals at potentially dangerous levels, reports researchers at Kingston University, London in the October 29 issue of Chemistry Central Journal.

A single glass of wine, regardless of its level of contamination, is not poisonous. But if like many people you have the habit of drinking a glass of wine a day, the gradual accumulation of contaminants in your body might prove to be hazardous.

The scientists used the THQ system in their analysis of the metal ions in wine.

THQ, or target hazard quotient, is a risk assessment system developed by the U.S. Environmental Protection Agency. It is designed to determine the safe levels of frequent, long-term exposure to various chemicals and compounds.

A THQ value of 1 is considered safe. Values over 1 indicate a health risk.

The wines subjected to analysis were produced in 15 countries in Europe, South America and the Middle East. The THQ values were calculated using data published in scientific journals. They did not include North American wines because there were no published data on heavy metals present in U.S. wines.

The researchers found that typical wines have THQs ranging from 50 to 200 per glass. But some wines had THQs exceeding 300.

In contrast, consumer concerns about heavy-metal levels in seafood become agitated when their  THQ values range from 1 to 5.

The most common metal ions found in the wines were vanadium, copper, and manganese. Four other heavy metals which showed THQs greater than 1 were detected: zinc, lead, chromium and nickel.

There were 30 other metal ions detected, but their THQ values could not be determined because their safe daily levels have not been established.

The presence of metal ions (charged particles) can pose problems to health. They can promote oxidative damage in cells. Oxidative damage from pro-oxidants is a key part of chronic inflammatory disease, which can lead to cancer.

Red wine, in particular, has been credited with health-promoting properties because it contains antioxidant chemicals. But the pro-oxidant metal ions could potentially negate the health benefits attributed to drinking red wine.

The level of lead found was relatively low compared to the other heavy metals. But high levels of manganese should raise concern: the accumulation of manganese in the brain leads to neurological damage, and it has been associated with Parkinson’s disease.

Wines from three nations showed safe levels: Italy, Brazil, and Argentina. Wines from Hungary and Slovakia had THQs exceeding 350. Wines from France, Austria, Spain, Germany and Portugal registered THQs over 100.

How did the heavy metals get into the wine? No one knows yet. The metals may occur naturally in the soil of the vineyards where the grapes were cultivated, or it may come from fungicides sprayed on the plants and from contaminants in the yeasts used for wine fermentation.

The researchers suggest that wine labels contain information on the amount of heavy metals in the wine.