Safety evaluation of heavy metals contaminated Astragalus membranaceus using health risk assessment model

Abstract

To evaluate the safety of heavy metals contaminated Astragalus membranaceus,an appropriate protocol was established to study the heavy metals pollution level by health risk assessment. This study provided a detailed procedure to assess the medicinal herbs in quality control and safety evaluation,and expected to create awareness among the public on the safety of consuming of A. membranaceus or any other kinds of medicinal herbs. The heavy metals content of Cu,As,Cd,Pb and Hg in a total of 45 batches of A. membranaceus were carefully analyzed with a developed inductively coupled plasma mass spectrometry( ICP-MS). Besides,the heavy metal contamination level was further evaluated through 4 main assessment parameters,including maximum residue limit( MRL) set by International Standard Organization,estimated daily intake( EDI) set by IUPAC,target hazard quotients( THQ) and Total THQ set by USEPA and total THQs in raw herbs of A. membranaceus. In addition,the recommended MRLs of 5 main heavy metals aimed to A. membranaceus were calculated based on the regulated consumption quantity. The result showed that,under the ISO international standard of Chinese medicine-Chinese herbal medicine heavy metals,the unqualified rate was 8. 89% for A. membranaceus,which including 4 batches of A. membranaceus exceeded the MRL of As. Here,the standard THQ value of A. membranaceus was firstly proposed as 0. 02 and 0. 011 25 for adults and children,respectively,which were calculated with the recommended consumption quantity of 30 g and 9 g for adults and children. Furthermore,the values of THQ for As and total THQs in adults and children were exceeded the standard THQ in A. membranaceus,and the recommended MRLs of Pb,Cd,Hg and Cu in above medicinal materials that calculated based on health risk assessment model were higher than the regulated MRLs that set by ISO and Chinese Pharmacopeia. The research showed that the contents of heavy metals in A. membranaceus were not in the safe range and the certain non-carcinogenic risks to human body cannot be neglected. Based on above investigation result,it is easily known that the common evaluation method for raw herbs based on the comparison of MRL of heavy metals was not precise enough,and the international model of health risk assessment should be built for each medicinal herb. Above all,this study provided a more realistic research approach for safety evaluation of any other kinds of heavy metals contaminated medicinal herbs,including the establishment of heavy metals standard limit in a specified medicinal herb under recommended consumption quantity,and it is expected to create awareness among the public on the safety of consuming any other medicinal herbs.