Survey of polycyclic aromatic hydrocarbons and lead in Chinese teas sold in Nigeria: levels and health implications

Background. The belief that Chinese teas are of immense health benefits by many Nigerians has led to high consumption rate. Objectives. This study has determined lead and polycyclic aromatic hydrocarbons (PAHs) levels of Chinese teas popularly consumed in Nigeria and to estimate the potential health risks. Material and Methods. Twenty brands of Chinese teas commonly consumed in Nigeria purchased in October 2014 were used in the study. Tea samples were extracted and digested. Lead, and PAHs were analyzed using an atomic absorption spectrophotometric (AAS) and gas chromatographic methods, respectively. Daily intake, percent violations of permissible limits, target hazard quotients (THQ), Health Risk Index (HRI) of lead, and other cancer risk parameters of PAHs were estimated. Results. All the tea samples except super natural green tea violated the WHO permissible limit of lead (0.01 mg/kg) by over 100%. The HRI ranged from 5.09 x 10-5 – 7.20 x 10-4 . Among the single analyzed compounds, the pyrenes had the highest concentration of 14.31 mg/kg. The intake of benzo[a]pyrene was detected in 25% of the samples which ranged from 0.066 to 0.145 mg/kg and exceeded the permissible daily limit of benzo[a]pyrene intake. The estimated cancer risk from this study in an adult is 5.07 x 10-9. Conclusion. The present study suggests that consumption of Chinese teas in Nigeria may not be one of the factors responsible for the increased rate of cancer in Nigeria.