Theeffect Of Rotation On Accumulation Of Heavy Metai And Health Risk Assessment Of Heavy Metai Pollution In Astragalus Membranaceus (Fisch.) Bge.Var.Mongholicus (Bge) Hsia

The environmental pollution has become more serious,leading to the accumulation of toxic substances such as heavy metals in the soil,water and air.Plants can accumulate heavy metals in their bodies through exposure to pollutants in the environment and soil,which poses a potential health threat to animals and humans.Astragalus membranaceus(Fisch.)Bge.var.mongholicus(Bge)Hsiao(A.mongholicus)is one of the commonly used Chinese medicinal materials in clinical practice and is in great demand.At present,most of the A.mongholicus on the market are artificially cultivated A.mongholicus,and it is difficult to guarantee its quality and safety.Heavy metal pollution is an important factor affecting the medicinal safety of A.mongholicus.In this experiment,A.mongholicus was the research object,the physical and chemical properties of soil,the accumulation of heavy metals in soil and A.mongholicus samples,and the content of medicinal components of A.mongholicus were compared after rotation of A.mongholicus and Solanum tuberosum L.and A.mongholicus continuous cropping.Analyzed the correlation between heavy metals and the difference of the enrichment of heavy metals on the spatial longitudinal scale.Four representative heavy metal pollution assessment methods were selected: single factor pollution index method,Nemeiro comprehensive pollution index method,non-carcinogenic risk assessment value and carcinogenic risk assessment value,to conduct a health risk assessment of heavy metal pollution of A.mongholicus from different origins.The content of flavonoids,astragaloside IV,polysaccharides and protein were used as indicators to evaluate the medicinal quality of A.mongholicus from 17 different producing areas.The result is as follows:1.The content of organic matter,total nitrogen,alkali-hydrolyzable nitrogen and quick-acting potassium in soil after rotation of A.mongholicus and Solanum tuberosum L was higher than that of continuous cropping soil;As and Cd content were lower than continuous cropping soil.The accumulation of Cu,Hg,As and Cd in the rotation is lower than that of the continuous crop.Rotation is beneficial to improve the physical and chemical properties of the soil and reduce the accumulation level of heavy metals in the soil and A.mongholicus.At the same time,rotation can promote the accumulation of flavonoids and astragaloside IV in the roots of A.mongholicus,and improve the quality of A.mongholicus.2.There are different chemical forms of heavy metals in the soil.The total ratio of the exchangeable and carbonate-bound state of the five heavy metals in the rotation soil is lower than that in the continuous cropping soil,and the biological activity is relatively low.The distribution of Cu,Hg,Cd,and Pb in different soil layers all show a vertical change law that gradually decreases with the increase of soil depth.3.The single factor pollution index and Nemeiro comprehensive pollution index showed that A.mongholicus from different producing areas was at the uncontaminated level.A.mongholicus from different origins has no risk of cancer.4.There are significant differences in the content of flavonoids and Astragaloside IV of A.mongholicus from different producing areas.A.mongholicus ingredients of Helinger County,Hohhot City,Damao County,Baotou City,Inner Mongolia Autonomous Region,Minle County,Zhangye City,Gansu Province,Wuzhai County,Yizhou City,and Hunyuan County,Datong City,Shanxi Province are high in content and good in quality.