Large-scale Detection And Comprehensive Risk Assessments Of Multi-pesticide Residues And Heavy Metals In Medicinal Plants

ObjectiveThe extrinsic contamination of medicinal plants is severe,which seriously affect the safety and effectiveness of medicinal materials.In order to explore the extrinsic contamination of medicinal plants with large-scale cultivation,this study collected a large number of samples on a spatial and temporal scale,aiming to establish the multi residue detection targets of medicinal plants and determine the contents of extrinsic contaminants of medicinal plants;establish the detection method system and a comprehensive risk assessment system for extrinsic contamination in medicinal plants;and construct universal standards and quality control system for extrinsic contamination in medicinal plants,so as to ensure the quality,safety and effectiveness of medicinal materials.Methods1.Detection of multi-residue pesticides in medicinal plantsA total of 1771 samples representing 182 different kinds of large-scale cultivated medicinal plants were analyzed by liquid chromatography tandem mass spectrometry(LC/MS-MS)and gas chromatography tandem mass spectrometry(GC/MS-MS).A total of 136 either frequently-detected,banned or highly toxic pesticides were determined through literature.A multi-residue detection system was constructed by LC/MS-MS and GC/MS-MS.Based on the formula of European Pharmacopoeia,the maximum residue limits(MRL)of pesticides were calculated.The detection rates and over-limit rates of pesticide residues in medicinal plants were calculated respectively2.Detection of heavy metals in medicinal plantsA total of 1773 samples representing 86 different kinds of large-scale cultivated medicinal plants were collected.Five kinds of heavy metals(Cd,Pb,As,Hg and Cu)were detected by inductively coupled plasma mass spectrometry(ICP-MS).Meanwhile,the existing standards of five heavy metals issued by 20 countries or regions and 7 international organizations were collected.The detection rates and over-limit rates of and heavy metals in medicinal plants were calculated respectively.3.Comprehensive risk assessments of multi-residue pesticides in medicinal plantsFor health risks induced by pesticide residues,dietary exposure assessment was employed to analyze the degree of risk pesticides in HM could pose to health and risk-ranking score to categorize and prioritize pesticides and HM by ranking.Additionally,for the first time,patient health impact was characterized to compare the risks of different pesticides and HM.Hazard Quotient(HQ)and Hazard Index(HI)were applied to quantify acute,chronic,and cumulative risks posed by pesticide residues in HM for dietary exposure assessment.The risk-ranking score(S)for pesticides and Risk Index(RI)for HM were obtained by multiplying three groups of individual scores which represent the toxicity of pesticide,the intake of pesticides,and the level of detectable residues.In addition,we quantified potential patient intake caused by pesticide residues in HMs and related cancer and non-cancer aggregated effect estimates based on methods developed for comparative impact assessment,and combined both into a set of comparative patient health impact scores(IS),expressed as disability-adjusted life years(DALYs).4.Comprehensive risk assessments of heavy metals in medicinal plantsFor heath risks induced by heavy metals,exposure assessment,non-carcinogenic risk assessment and carcinogenic risk assessment were used to explore the potential impacts.When calculating each risk indicator,the minimum,mean and maximum concentrations of each metal in each medicinal plant were involved in the calculation.For exposure assessment,the EDI(Estimated daily intake)of each metal in each kind of medicinal plant was calculated then compared to its corresponding PTDI(Provisional Tolerable Daily Intake);For non-carcinogenic risk assessment,the non-carcinogenic Hazard Quotient(HQ)of each metal in each medicinal plant,as well as the total non-carcinogenic Hazard Index(HI)of each medicinal plant was calculated;For carcinogenic risk assessment,the Carcinogenic Risk(CR)of three metals in each medicinal plant was calculated then compared to its corresponding CSF(Cancer severity factor),the total CR of three metals in each medicinal plant was also calculated.Results1.Detection and over-limit rates of multi-residue pesticides in medicinal plantsAt least 88.03%(1559)samples were present with pesticide residues and 59.01%(1045)samples with over-limit pesticides levels.Thirty-five of the total(136)pesticides were considered banned based on collective regulations of the European Union(EU),United States(US),and China.The 35 banned pesticides were detected in at least 42.97%samples(761),of which mevinphos and total dichlorobiphenyl trichloroethane(DDT)accounted for 24.20%(242 of 1000 samples by LC/MS-MS)and 13.10%(101 of 771 samples by GC/MS-MS),respectively.Furthermore,eight banned pesticides appeared at concentration levels over 500 times higher than the EP limit.Chrysanthemi flos were detected with 37 pesticides(eight over-limit and seven banned),followed by Crataegi fructus(29 pesticides)and Alpiniae oxyphyllae fructus(27 pesticides).HM were divided into five categories,according to the part of the plant used for medicinal properties:fructus&semen,radix&rhizoma,flos,folium&cortex,and herba&others.Our findings indicated pesticides were most widely detected in radix&rhizoma(48.62%,n=1559)and the least in flos(5.77%,n=1559).Pesticides presenting the highest risk belonged to the organophosphorus insecticide group.Insecticides and fungicides were those most frequently detected(45.42%and 33.69%,respectively,n=6387).2.Comprehensive risk assessments of multi-residue pesticides in medicinal plantsAs per risk assessments of pesticide residues,in total ten medicinal plants presented with unacceptable acute dietary exposure risk(HIa>1),including Crataegi Fructus(HIa=12.09),Zanthoxyli Pericarpium(HIa=11.54),Lycii Fructus(HIa=1.86),and Corydalis Bungeanae Herba(HIa=1.48).A total of 23 different kinds of herbal medicines presented with unacceptable chronic dietary exposure risk(HIc>1),including Crataegi Fructus(HIc=6.62),Myristicae Semen(HIc=3.51),and Zanthoxyli Pericarpium(HIc=3.38).Crataegi Fructus and Zanthoxyli Pericarpium presented with the highest acute and chronic exposure risk(HQa and HQc),as well as acute and chronic cumulative exposure risk(HIa and HIc).While banned pesticides carbofuran and mevinphos presented with the highest HQ in dietary exposure assessment.Additionally,medicinal plants with fructus&semen utilized are found to present the highest risk in dietary exposure assessment.For risk-ranking score,Carbofuran-3-hydroxy and leptophos appeared with the highest risk-ranking score(S=140)in Crataegi Fructus,Lycii Fructus,Lonicerae Japonicae Flos,and Taraxaci Herba.While Crataegi fructus occupied the top in Risk Index(RI=1925),followed by Dendrobii Caulis(RI=1315)and Saposhnikoviae Radix(RI=1144).According to Spearman coefficient,the level of detection(p=0.783)contributed the most to the risk-ranking,followed by the toxicity of pesticide(p=0.691),and the least relevant was the consumption of herbal medicines(p=0.370).Herbal medicine Coicis semen(min ISh=3945.40 ?DALY·person-1,mean ISh=3972.07 ?DALY·person-1)and Radix chuanmingshinis violacei(ISh=4287.78 ?DALY·person-1)posed the most severe risk according to patient health impact approach.Pesticide in o,p'-DDT in Coicis semen(min ISi,h=2729.58 ?DALY·person-1)and Radix chuanmingshinis violacei(mean ISi,h=2837.91 ?DALY·person-1,max ISi,h=3682.78 ?DALY·person-1)also posed the most severe risk.Total DDTs,carbofuran,mevinphos,leptophos,and methomyl are all banned pesticides and highly toxic.Besides being nephrotoxic and hepatotoxic,they are also carcinogenic,genotoxic,and affect reproductive and developmental system.Crataegi fructus ranked high in three assessments and it belongs to the fructus&semen category,thus considered the most risk-inducing HM in need of special surveillance and monitoring.3.Detection and over-limit rates of heavy metals in medicinal plantsThe heavy metals were detected in all medicinal plant samples.A total of 30.51%(541)samples were detected with at least one heavy metal exceeding the standard of Chinese Pharmacopoeia(2020 Edition).Among which,433 samples were detected with one over-limit metal,75 with two over-limit metals,24 with three over-limit metals,and 9 with four over-limit metals.The over-limit rates of the five heavy metals were Pb(102,5.75%)>Cd(88,4.96%)>As(74,4.17%)>Hg(67,3.78%)>Cu(31,1.75%).The highest concentration of Hg was detected in Chrysanthemi Flos,which was 66.17 times higher than the standard.The highest concentration of Pb was in Platycodonis Radix,9.02 times higher than the standard.The over-limit rate of folium&cortex medicinal plants was 9.68%,and that of fructus&semen was 16.13%,41.94%for herba&others,and 19.35%for radix&rhizoma.The detection rate of heavy metals in fructus&semen was the highest,while the over-limit rate of heavy metals in herba&others was the highest.The over-limit rate of Pb is the highest,followed by Cd and As.4.Comprehensive risk assessments of heavy metals in medicinal plantsFor exposure assessment of heavy metals,Pb,Cd,As,and Hg have higher than acceptable risks in 25 kinds of herbs.The maximal Estimated Daily Intake(EDI)of Pb in seven herbs,of Cd in five,of Hg in four,and As in three exceeded their corresponding Provisional Tolerable Daily Intakes(PTDI).In total 25 kinds of herbs present an unacceptable risk assessed with the HQ(Hazard Quotient)or HI(Hazard Index).Plantaginis Herba(HI=11.47)posed the highest non-carcinogenic risk while Andrographis Herba with the highest carcinogenic risk(CR=5.27E-09).As posed the highest non-carcinogenic risk(HQ=9.95)and highest carcinogenic risk(CR=4.48E-09).ConclusionPesticides were most frequently detected in plants with radix and rhizoma for medicinal use,while least detected in flos medicinal plants.Medicinal plants used with fructus and semen presented with the highest risk representative by Crataegi Fructus.Heavy metals were most frequently detected in plants with fructus and semen for medicinal use,while the over-limit ratio was the highest in medicinal plants of herba category.The pesticides with the highest risks were organophosphorus insecticides.Total DDTs,carbofuran,and mevinphos have been identified as the most risk-inducing pesticides.Heavy metal As presented with the highest carcinogenic and non-carcinogenic risks in medicinal plants.This study is a large-scaled detection and risk assessments of extrinsic contaminants in medicinal plants,it can therefore provide data support for standard formulation,production monitoring system of standardized cultivation and quality supervision of medicinal materials.