[Study on the baseline contents and reference maximum limit standard of heavy metals and harmful element of 23 Chinese herbs in Northern China].

Objective: This study was carried out to obtain the baseline contents and establish the reference maximum limits of heavy metals and harmful element in China.

Methods: According as Chinese standard methods of heavy metals and harmful element, 254 Chinese herbs were determined.

Results: The contents of lead, cadmium, mercury and arsenic in different Chinese herbs were (1.78 +/- 1.98), (0.17 +/- 0.24), (0.04 +/- 0.06) and (0.72 +/- 0.69)mg/kg, respectively. In the process of establishing the reference maximum limit standards of these harmful substances, the dietary intakes which including the intakes from food, beverage and drinking water were necessarily considered. The intakes including dietary and Chinese herbs of per person per day (and the percent of ADI) of lead, cadmium, mercury and inorganic arsenic were 102.9 microg (45.7%), 21.4 microg (34.0%), 5.7 microg (5.7%) and 81.0 microg (60.5%), respectively. We recommended the reference maximum limit standards of lead, cadmium, mercury and arsenic which in Chinese herbs were 5.0 mg/kg, 0.3 mg/kg, 0.2 mg/kg and 2.0 mg/kg, respectively.

Conclusion: The survey of baseline level of heavy metals and harmful element was successful. The intakes of these harmful substances were safe to human health. The maximum level standards of lead, cadmium, mercury, arsenic in plant Chinese herbs submitted by our coordinated group have been accepted by Chinese Herbs Codex, 2005 version. This standard is suitable for quality standards in plant Chinese herbs.