Traditional Chinese Medicines Often Contaminated With Mercury & Arsenic

Using a stringent two test method, researchers have found that 32 out of 32 traditional Chinese medicines tested were contaminated with mercury and arsenic.

AsianScientist (Mar. 30, 2016) – Traditional Chinese medicines are perceived as natural—even benign and with few side effects—but regulation of human medicines fluctuates widely in different countries.

Now, a study published in Toxicological & Environmental Chemistry has raised questions about what controls should be implemented regarding the use, importation and production of traditional Chinese medicines. The research team, led by Dr. Etsuko Furuta from Ochanomizu University and Professor Nobuaki Sato from Tohoku University, found that many medicines contained toxic mercury, arsenic and sulfides.

Furuta and Sato analyzed the chemical make-up of 32 Chinese medicines, 21 of which were purchased online and the rest from Japanese markets and pharmaceutical companies. They employed two non-dissolving methodologies to test the medicines; instrumental neutron activation analysis (INAA) to examine the concentrations of any hazardous elements present, and X-ray diffraction (XRD) to determine chemical structures of high concentration elements present.

The results from these tests showed the presence of arsenic and mercury in all samples. Additionally, the results showed that medicines with identical names but different places of production had considerably inconsistent concentrations of these hazardous elements.

The tests also revealed that the use of INAA and XRD together yielded the most accurate results for quantitative and structural analysis; XRD alone failed to detect low levels of arsenic and mercury in some samples but without it the chemical structure of elements present could not be determined.

Most of the traditional Chinese medicines purchased had no ingredient sheet, which would make product evaluation difficult for the customer. However, those which did have an ingredient sheet were not always right; tests revealed the presence of unlisted hazardous ores and again widely varying concentrations of others or different ingredients in identically named medicines.

The researchers point out that raised levels of mercury are likely due to environmental contaminants, yet another indicator for the need for stricter regulation of traditional Chinese medicines and their use.

This study reveals a very unclear picture of safety in Chinese medicines. Despite their historically unregulated use, the authors urge for tighter controls on importation, better information on their chemical structures, and thorough consultation with a doctor before regular use.

The authors conclude that “a long-term continuous consumption of these herbs should be avoided.”

The article can be found at: Furuta and Sato (2016) Quantitative and Structural Analyses of Hazardous Elements in Chinese Medicines and Herbs.


Source: Taylor & Francis Group; Photo: Shutterstock.
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