Polycyclic aromatic hydrocarbons contamination levels of dried herbal teas and their infusions

Medicinal plants and herbs are commonly used for preparing teas as water infusions but they may be contaminated with environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs). The aim of the study was to assess the contamination levels of polycyclic aromatic hydrocarbons in dried herbal teas and their transfer into water infusions. The PAHs concentrations were determined in dried tea from five plant species: Matricaria chamomilla L., Thymus serpyllum L., Tilia tomentosa Moench, Sambucus nigra L. and Achillea millefolium L. Dried herbal teas from different commercial brands were purchased from Bulgarian markets. Detection of PAHs was performed using gas chromatography coupled with mass spectrometry (GC-MS). In dried tea samples, PAHs with 3 and 4 aromatic rings were predominant with a contribution over 79%, whereas 5-6 rings PAHs were not detected. Benzo[a]pyrene was found below the limit of detection both in dried teas and their water infusion. The results showed white yarrow as the least contaminated herbal tea, while teas made of Tilia tomentosa Moench (linden) were more polluted (mean total content of 13 PAHs-274 & mu;g/kg dw). The mean content of PAHs in infusions ranged from 185 to 478 ng/L (in white yarrow and linden teas, respectively). The mean transfer rates of sum 13 PAHs from dried herbs into water infusions were found in the range 15.4-56.7%. The potential health risk by tea consumption was assess by evaluation of daily intake of PAHs.