CAIRO: A recent medical study found local commercial tea supplies to include increases in lead concentration, causing some alarm to consumers and producers.
In a research paper done by the Hot Laboratories and Waste Management Center of the Egyptian Atomic Energy Authority, six brands of tea from the Egyptian market were collected and tested to analyze their levels of heavy metals.
The study, released in the International Journal of Physical Sciences last month, found that Magnesium and Iron were the most prevalent metals in tea brew, and that lead and copper were the least prevalent.
The research paper, titled, Annual effective dose and concentration levels of heavy metals in different types of tea in Egypt was accepted by the International Journal of Physical Sciences in April of 2008.
The presence of lead and other metals can be explained by plants taking up heavy metals from the soil, according to the study.
Citing studies done in past years, the report also pointed out that levels of aluminum have been found in tea.
Six brands of black tea and one of green tea were studied by two methods.
In the first, two grams of black tea particles or a tea bag were boiled with water. In the second, hot water was added to black tea particles or to a tea bag.
Green tea was found to have the highest levels of the metals; Zinc, Magnesium, Iron, Copper and Lead and Cobalt.
In addition, the studies findings reported that contents of heavy metals in brew were lower than in infusion
The study also established a link between high levels of metal and the presence of nucleotides, saying that nucleotides can be accumulated from these high levels. Green tea was also found to have the highest level of alpha gross activity of naturally occurring nucleotides.
One can conclude that the presence of high amount of heavy metals can lead to the accumulation of some naturally occurring radionuclides especially uranium and thorium and or their relative daughters.
According to Dr Abdel Hakim Kandil, a nuclear scientist from Helwan University, the limit of radioactive materials that can be consumed by humans is 0.1 rem (unit of absorbed radiation) per week.
He says, the magnesium in tea is not radioactive, adding that these only become radioactive if placed in a nuclear reactor.
He also points out that radioactivity is in the air itself, it interacts with nitrogen to produce Carbon 14, this becomes part of Carbon dioxide in air, we inhale part of the Carbon dioxide.
Dr Mohamad Elmi, the World Health Organization s Regional AdviserFood and Chemical Safety, said that Magnesium is not toxic, and the amount that we get from drinking tea does not exceed the toxic limit. He also noted that magnesium is nutritionally essential, and can be obtained from various other sources such as water, citrus and milk, to name a few.
The level of magnesium in tea is limited, it s neglible – it s good to have magnesium to help your endocrine system, calcium, cardiac system.
In regards to possibility of radioactive particles in tea, Elmi noted that the irradiation of food for herbs and spices is necessary to ward off fungus.
All these spices have to be irradiated, we expose them to radiation. Why we irradiate them? We don t want fungus to grow.
The research paper also noted that most of human exposure to radiation originates from natural sources, external sources of radiation, and inhalation or ingestion of radioactive material.
The study ended with this recommendation: Generally, referring to the study of heavy metals, it is recommended to decrease green tea drink intake as well as the tea drinking by infusion process.
