Detection and Analysis of Lead,Cadmium and Arsenic Content in Common Vegetables

This study was carried out to detect content of heavy metals( Pb,Cd,and As) in vegetables,understand the current situation of heavy metal contamination in vegetables,and to provide scientific reference for further researches. It randomly selected 6 large vegetable markets and 6 supermarkets in Changsha City,selected 8 types of typical vegetables,and detected 96 samples. In accordance with maximum level of contaminants in foods in existing GB2762- 2012 standard,Nemerow composite pollution index( Pt) and grading standards,it made evaluation: uncontaminated( Pt≤ 1),mildly contaminated( 1 < Pt≤2),moderately contaminated( 2 < Pt≤3),and highly contaminated( Pt>3). Among 96 samples,range of content of Pb,Cd and As is( 0. 06- 1. 41),( 0. 06- 1. 26) and( 0. 00- 0. 91) mg / kg respectively; the over- limit rate of these metals exceeding the safety level is 78. 13%,45. 83%,and 34. 38% separately; the composite pollution index is in( 0. 90-6. 05),the eggplant is 6. 05 and hot pepper is 3. 24; the content of Pb( F =23. 908,P =0. 001) and Cd( F =64. 908,P =0. 000)are significantly different between 8 types of vegetables and there is no significant difference between the content of As( F = 4. 634,P = 0. 705> 0. 05) in 8 types of vegetables. Study shows that common vegetables in Changsha City has problem of excess Pb,Cd and As,and the Pb over- limit rate is the highest. The composite pollution index indicates that most heavy metal contamination of vegetables is mild and moderate contamination,melon,fruit and vegetable contamination is high contamination,and Cd is the major factor leading to contamination of melons,fruits and vegetables.

Phytoaccumulation of Arsenic, Cadmium and Lead by Brassica juncea Parents and Their F1 Hybrids

Although Brassica juncea (Indian mustard) is reported to be a good accumulator of metals, little is known of the selected varieties of B. juncea (cvs. Rai and BARI-11). This paper investigates the phytoaccumulation of arsenic, cadmium and lead by B. juncea (cvs. Rai and BARI-11) parents and F1 hybrids. The experiment was conducted in the hydroponic media in the greenhouse of University of Southampton under a Randomised Block Design. Sodium arsenite, cadmium sulphate and lead nitrate with 0 ppm, 0.5 ppm and 1 ppm were used. The cadmium treated plants were analysed by Varian Atomic absorption spectrophotometer-200. The samples of arsenic and lead were analysed by Inductively Coupled Plasma Atomic Emission Spectrophotometer. The results suggest that arsenic was detected only in the root systems while cadmium and lead were detected both in the root and shoot systems. Significant differences in the uptake were observed for different concentrations. Accumulation of arsenic was detected only in the root systems of B. juncea (cvs. Rai and BARI-11) at lower concentrations. Hence, this can be used as an agriculturally viable and efficient phytoaccumulator in the arsenic affected areas where contamination level is low and the contamination occurs at the rooting level.

Assessment of Bacteriological and Metallic Contamination (Pb, Cd, As) and Analysis of Toxicological Risks in Houin Logbo (Lake Toho) in the Municipality of Lokossa

Heavy metals are dangerous pollutants for ecosystems, especially aquatic ecosystems, because of their concentration in certain living organisms and their presence in the food chain. This study aims to evaluate the bacteriological, metallic (Pb, Cd, As) and toxicological risks associated with houin logbo (toho lake) in the municipality of Lokossa. The results obtained concern everyone: Toho lake is contaminated by Escherichia coli and faecal enterococci, concerning the evaluation of the metallic contamination we have: water (Pb: 0.1032, Cd: 0. 046, As: 0);sediment (Pb: 14.79, Cd: 1.27, As: 0.800);Oreochromis niloticus (Pb: 0.143, Cd: 0.087, As: 0.466);soils (Pb: 8.528, Cd: 2.755, As: 0.833);Solanum lycopersicum (Pb: 0.098, Cd: 0.066, As: 0). Consumption of lake fish (Oreochromis niloticus) and market garden produce (Solanum lycopersicum) exposes populations, especially children, to the risk of As and Cd poisoning.

Analysis of Some Elements and Speciated Compounds in Fish Found in the New Calabar River of the Niger Delta Area,Nigeria

The flesh of guinean and blackchin tilapia,and mullet found in Choba river were collected for elemental studies of mercury,cadmium,lead,arsenic,nickel and speciated forms.Analytical method of X-ray fluorescence(XRF)was used for the elemental studies while Gas chromatographymass spectrometer(GC-MS)was used for the speciated forms.4.3 mg/kg was the highest concentration of cadmium observed in blackchin tilapia.The three fish species all contained about 0.5 mg/kg of arsenic and 1 mg/kg of mercury.1.7 mg/kg of lead was detected in mullet while 7.3 mg/kg of nickel was detected in blackchin tilapia.Organometallic compounds found were nickel tetracarbonyl,borane carbonyl in guinean tilapia,nickel tetracarbonyl,borane carbonyl and germanium(iv)pthalocyanine dichloride in blackchin tilapia and[μ-(ƞ6-benzene)]bis(ƞ5-2,4-cyclopentadien-yl)di-μ-hydrodi-vanadium.Borane carbonyl was found in mullet.

南通地区部分稻谷中铅、镉、铬及无机砷的污染状况分析

目的:测定南通地区部分稻谷中铅、镉、铬及无机砷含量,为安全食用提供依据。方法:采用微波消解处理样品,使用电感耦合等离子体质谱仪(ICP-MS)、液相色谱-原子荧光谱仪进行测定,并根据GB 2762-2017国家标准,采用单因子污染指数法和重金属综合污染指数法进行评价。结论:两个地区40份稻谷普遍存在重金属污染,且铬污染较严重。

基于能量色散XRF光谱的土壤重金属As与Pb同时定量分析方法

针对能量色散XRF光谱难以实现土壤重金属Pb与As的同时准确定量检测问题,基于Pb元素Lα、Lβ及As元素Kα、Kβ的谱峰特性,提出了一种能量色散XRF光谱土壤重金属As与Pb同时定量分析方法。该方法通过构建不同浓度Pb元素Lα与Lβ特征峰强度关系,根据实测样品Pb元素Lα与As元素Kα重叠峰强度信息,准确解析Pb元素Lα及As元素Kα特征峰强度,基于已建立的定量分析曲线实现土壤样品中Pb与As的准确反演。通过对不同浓度Pb与As共存土壤样品定量检测,相比ICP-MS测量结果,本文方法对20.25~844.84mg·kg-1重金属Pb检测的相对误差在0.86%~11.09%之间,平均相对误差为6.17%;对26.99~825.93mg·kg-1重金属As检测的相对误差在0.10%~14.72%之间,平均相对误差为8.11%,实现了Pb与As共存土壤中Pb与As含量的同时准确定量分析,为发展土壤重金属现场快速XRF精准检测设备提供了方法。

光谱法测定农产品中铅镉铬汞砷的一次性消解方法

为了缩减检测用时与降低综合成本,对农产品中铅、镉、铬、汞、砷的检测方法进行改进,对检测条件进行优化和协调试验,探索一次性消解定容同时检测5种重金属元素的可行性。通过理论分析和试验研究,参考国标方法和成熟文献上的方法,消解用酸中加入盐酸和高氯酸,消解前120℃预消解30 min,消解赶酸后加入20 g/L硫脲+50 g/L抗坏血酸溶液转移定容,铅、镉检测加入磷酸二氢铵基体改进剂,砷、汞同时检测。通过条件取舍与优化,达到使用原子吸收(AAS)和原子荧光(AFS)同时检测的目的。检测标准物质和标准溶液,测定值均在其1倍不确定度范围内,准确度良好,相对标准偏差均小于20%,精密度良好。改进方法检测结果较准确,操作简便,适用于利用AAS和AFS对农产品中铅、镉、铬、汞、砷的测定。

砷、镉、铅复合污染场地修复实例研究

通过对该项目的研究,分析重金属污染场地修复工程的全流程。分析固化稳定化修复砷、镉、铅复合污染土壤的工程实例。确认固化稳定化修复重金属污染土壤的原理是通过固化稳定化药剂与重金属进行物理化学反应生产难溶物质固定在土壤中防止其浸出,降低其危害,但并没有完全消除危害,需配合阻隔填埋、长期监测和场地管控措施综合使用。同时,对不同固化稳定化药剂选择,确认一种商品化的药剂,对此项目的长期研究可以评估此药剂的长期效果,为类似其他项目的选用提供相应工程技术和药剂固化效果参考。

粗铅冶炼过程中砷镉铊的走向分布及治理措施

在粗铅冶炼工艺中,铅精矿和其他含铅物料中的砷、镉、铊分布于各工序环节,不利于有价金属资源的回收,而且加大了冶炼废弃物的处理难度,另外还对人体健康和环境造成负面影响。现有文献对于砷、镉、铊在粗铅冶炼过程中的分布及趋向还未见报道,本文根据某冶炼企业实际生产情况,统计了2021年及2022年分别为期14d的两套物料平衡数据,对砷、镉、铊在各冶炼工序的分布进行了分析,得到以下结论。砷的分布情况:在底吹炉工序中,约85%砷进入高铅渣,约9%砷进入烟灰,约6%砷进入硫酸净化污酸系统;在还原炉工序,约70%以上砷形成铅铜锍进入粗铅,约20%砷进入还原炉烟灰,10%以下的砷通过还原渣进入烟化炉。镉、铊的分布情况:高度富集于底吹炉和侧吹炉烟灰中,其中底吹炉烟灰中富集比例为85%~95%,只有5%~15%进入高铅渣转至还原炉工序,极少部分进入硫酸系统。企业采用开路底吹炉烟尘方式减少粗铅冶炼系统中砷、镉、铊的含量,开路标准是烟尘含镉超过20%时从收尘系统开路,当烟尘含镉低于15%停止开路,取出的烟尘可直接作为回收镉的原料外售。本文分析结果及解决方法可为同类企业控制冶炼系统中砷镉铊的分布提供参考。

南宁市米粉污染物监测情况分析

目的:为了了解南宁市米粉食品安全现状,分析南宁市干湿米粉镉、铅、总砷、含铝添加剂和二氧化硫超标及检出情况,为食品安全风险监测、评估、预警提供科学依据。方法:2020—2023年按照《广西食品污染物和有害因素风险监测工作手册》的要求随机抽样,采集317份样品。按照《广西食品污染物和有害因素风险监测工作手册》相应的操作程序和规定标准进行检测。结果:所采集的米粉中镉、铅、总砷的超标率分别为0.64%、0.32%、0.43%,含铝添加剂、二氧化硫的检出率分别为14.88%、7.18%。结论:南宁市米粉受镉、铅、总砷污染较轻,未受到含铝添加剂污染,可能存在二氧化硫摄入过量的风险。建议继续关注米粉中镉、铅、砷、二氧化硫的污染情况。

电感耦合等离子体发射光谱法同时测定铅冶炼工作场所空气中的铊砷镉等有害元素

针对铅冶炼工作场所空气中的铊、砷、镉等的含量的快速检测难题,利用升级改造后电感耦合等离子体发射光谱仪,通过使用微孔滤膜收集空气中烟尘,采用高氯酸、硝酸进行消解溶样,配制铊、砷、镉等标准溶液,使用ICP-AES仪器进行铊、砷、镉谱线的选择和干扰校正,能够实现一次溶样,同时完成多种重金属有害元素测定,方法准确快捷,试验研究加标回收率在98%~103%之间,铊、砷、镉的检出限分别达到0.001 5μg/mL、0.002 1μg/m、0.000 1μg/mL等,很好地满足了企业对空气中有害元素快速检测需求。

A study of differential potentiometric stripping analysis for lead and cadmium with Nafion coated carbon fibre electrode

The differential potentiometric stripping analysis (DPSA) with Nafion coated carbon fibre electrode has been studied, and a method to determine lead and cadmium in urine directly has been attempted. The effect of various experimental parameters on the DPSA response is discussed. The experimental conditions include 0.2M sodium perchlorate, deposition potential of-1.0 or -1.1 V and using 20 ppm mercuric ion as oxidizing agent. The response of the signal is in linear relation with the concentrations of lead and cadmium respectively up to 0.5 ppm. The electrode coated with Nafion film alleviates the interference from organics in urine samples.

Cumulative Risk Assessment of Exposure to Heavy Metals through Aquatic Products in China

Objective This study aimed to assess the risk of cumulative exposure to Pb,Cd,Hg,and iAs through aquatic products consumed by Chinese people.Methods Heavy metal concentration data were obtained from the national food contamination monitoring program during 2013–2017.Consumption data were derived from the China National Food Consumption Survey in 2014 and the relative potency factor(RPF)method was used to estimate cumulative exposure for neurotoxicity and nephrotoxicity.Results The results demonstrated that the cumulative exposure based on neurotoxicity was below the lower confidence limit on benchmark doses of lead(BMDL01)for nephrotoxicity and the cumulative exposures were all lower than the provisional tolerable monthly intake(PTMI)of Cd.However,the margin of exposure values(MOEs)of the cumulative exposures for neurotoxicity in the 2–6 year-old group was close to 1 and the cumulative exposure level for nephrotoxicity accounted for 90.21%of the PTMI.Conclusion The cumulative exposures of the 2–6 year-old group to the four heavy metals did not reach(but came close to)the corresponding safety threshold for both neurotoxicity and nephrotoxicity.Given that there are still other food sources of these four heavy metals,it is necessary to more closely study their cumulative health effects.

Quality of Potable Water Available to the Residents of Anambra State, Nigeria

Public pipe-borne water system had collapsed in Anambra state of Nigeria, for over fifteen years, challenging the residents of the state to resort to alternative sources of potable water, notably, boreholes. It is imperative to continuously assess the quality of the water. In this work, two boreholes each in nineteen communities, one from Aguluzigbo, in three local government areas?(Anaocha, Awka-North, Awka-South) in the state were sampled, and tested for pH, Conductivity, Hardness, Total Suspended Solids, Lead, Arsenic, Cadmium, Bacteria and Yeast loads. The water samples were all soft and mostly acidic. While there were not much threats of yeast, the aerobic bacteria counts were above the acceptable limits. The Lead, Arsenic and Cadmium concentrations were above the tolerable limits in most communities in Anaocha and Awka-South. Arsenic, Lead, Cadmium were absent in all the samples in Awka-North except in four communities where Cadmium was present. Suspended solid contents were also high in all the Local Government Areas. Overall, the quality of the water consumed by the people in the selected population calls to question?of?the water and sanitation component of the public health system.

铅、镉同位素在重金属污染源解析中的应用--基于CiteSpace计量分析

为了解铅(Pb)、镉(Cd)同位素在重金属污染源解析应用方面的研究进展及未来发展势态,以Web of Science核心数据库中2008-2021年的相关文献为研究对象,运用CiteSpace软件对文献进行可视化分析。结果表明:2008-2021年国际上本研究领域的英文发文数量呈波动增长趋势,2015年后文献量增长幅度较大。在此期间,国际上本领域的研究大致划分为2个时期:2008-2014年,研究焦点侧重于工业、采矿、冶炼等行业的重金属污染状况研究,主要涉及大气、水体和沉积物(湖泊、水库和河流)等介质的重金属污染源解析;2015-2021年,研究焦点逐渐转向重金属与人体健康领域,重点关注土壤及农作物重金属的污染源解析、食品安全和人体健康风险评价等问题。总体上,Pb、Cd同位素在重金属污染源解析应用方面的研究由单一同位素解析、单一环境介质应用向多同位素联合解析、多介质应用方向发展。

钝化材料组合对酸性土壤镉铅砷和中微量元素有效性的影响

采用土壤培养试验的方法,研究了在同等剂量下(6 g/kg土)海泡石(S)、铁锰矿粉(F)和生物炭(B)及其组合对酸性土壤镉(Cd)、铅(Pb)、砷(As)、锌(Zn)、铁(Fe)、锰(Mn)有效性的影响,以期筛选出同步钝化酸性土壤镉铅砷且对中微量元素锌铁锰有效性影响小的钝化材料组合。结果表明:海泡石、铁锰矿粉、生物炭及其组合均在一定程度上提高了土壤pH,降低了土壤中Cd、Pb和As的有效态含量,组合处理降低了土壤Cd、Pb和As有效性的效果均优于单施处理。3种钝化材料及其组合在一定程度上降低了土壤中Zn的有效态性,3种钝化材料及其大多数组合降低了土壤Fe和Mn有效性。S_(5)F_(1)B_(0)组合同步钝化土壤Cd、Pb和As效率均较高,该处理土壤有效态Cd、有效态Pb、有效态As和有效态Zn含量比CK分别降低了30.9%、84.5%、60.2%和32.5%,有效态Mn含量上升了19.9%。土壤中有效态Cd、Pb、Zn和Mn含量与pH均显著负相关。S_(5)F_(1)B_(0)组合同步钝化复合污染土壤Cd、Pb、As的效率均较高,可适当提高土壤Mn的有效性,应用时需适当补充Zn元素。

安徽省四种市售水生蔬菜中铅、镉、总铬和总砷污染状况

目的检测安徽省市售水生蔬菜中的铅、镉、总铬和总砷4种重金属/类金属元素,并评估其污染状况。方法电感耦合等离子体质谱测定四种主要水生蔬菜中铅、镉、总铬和总砷。评价依据《食品安全国家标准食品中污染物限量》(GB 2762-2022)以及单因子污染指数法和综合污染指数法。结果4种水生蔬菜主要受到铅和镉的污染,其超标率分别为22.8%(23/101)和49.5%(50/101)。鱼腥草中铅的超标率为50.0%(21/42),且鱼腥草中铅含量的最大值为其限值的6.92倍。芋头、芦蒿和鱼腥草镉的超标率分别为35.7%(10/28)、85.7%(12/14)、66.7%(28/42),芦蒿中镉含量的最大值为其限值的4.4倍,鱼腥草中镉的最大值为其限值的4.6倍。水芹的综合污染指数小于0.7,处在安全水平。芋头的综合污染指数为0.9,处在警戒限水平。芦蒿镉的污染指数为2.1,表明芦蒿受到了镉的中度污染;其综合污染指数为1.6,为轻污染状态。鱼腥草中铅和镉的污染指数为1.6和1.5,表明鱼腥草受到了铅和镉的轻度污染;其综合污染指数分为1.3,处于轻污染水平。结论安徽省市售4种水生蔬菜受到铅、镉的污染,需引起农业、市场监管等部门的重视,加强对铅、镉污染的预防及监测工作,以保障水生蔬菜的安全。

铅锌矿石稀散元素镉含量的高光谱反演研究

稀散元素矿产资源是国民经济中的关键性矿产资源,元素含量的提取是矿产资源潜力评价、靶区优选的基础。现有稀散元素含量分析面临快速检测、潜力评价的需求,基于高光谱的稀散元素含量反演是解决此问题的一种途径。因此,采集西藏斯弄多-则学矿集区的铅锌矿石,开展铅锌矿石稀散元素镉(Cd)含量的高光谱反演方法与反演模型研究。选用ASD Field Spec 3地物光谱仪及配套软件进行光谱数据采集和预处理;在光谱特征分析基础上,开展一阶微分(FD)、二阶微分(SD)、倒数的对数(AT)、倒数对数的一阶微分(AFD)、倒数对数的二阶微分(ASD)光谱数据变换处理,结合皮尔森相关性系数(r)筛选特征波段,进行随机森林(RF)、人工神经网络(ANN)、支持向量机(SVM)模型构建与反演,选用决定系数(R2)和均方根误差(RMSE)评价反演模型效果与预测精度。结果表明:样品反射率集中于40%~60%区间;1420、1920和2200 nm处形成吸收峰;特征波段覆盖可见光和近红外波段,771~2051 nm为特征波段的最优区间。SD光谱变换的降维效果最好,筛选出15个特征波段;其次为ASD和AFD光谱变换,分别筛选出8个和2个特征波段。FD与AT光谱变换未筛选出特征波段。SD筛选的特征波段用于反演,镉元素含量预测效果最好的是SD-ANN模型(R2=0.884,RMSE=2.679),其次是SD-SVM模型(R2=0.830>0.8,RMSE=1.382),SD-RF模型预测效果最差(R2=0.505<0.6)。ASD筛选的特征波段用于反演,镉元素含量预测最好的是ASD-SVM模型(R2=0.857,RMSE=2.198),其次是ASD-ANN模型(R2=0.846,RMSE=2.625)。对比分析,镉元素含量的高光谱反演模型效果为:SD-ANN>ASD-SVM>ASD-ANN>SD-SVM>ASD-RF>SD-RF。该研究总结了铅锌矿石稀散元素镉的高光谱特征,建立了镉元素含量的高光谱反演方法及模型,为镉等稀散元素含量的高光谱反演、无损检测、快速分析提供了参考,为高海拔勘探区稀散元素矿产资源的潜力评价、靶区优选提供了科学支持。

糊化制样X射线荧光光谱法快速检测鲜香菇中的铅、砷、镉

目的建立糊化制样能量色散X射线荧光(energy-dispersive X-ray fluorescence,EDXRF)光谱法快速检测鲜香菇中铅(Pb)、砷(As)和镉(Cd)的新方法。方法鲜香菇样品与稀硝酸水溶液均质糊化后,直接进行EDXRF光扫描,通过谱峰识别进行定性,以加标校正曲线进行定量。结果样品基质中待测元素谱峰无干扰,方法线性良好(r 2≥0.995);Pb、As和Cd的检出限分别为0.34、0.14和0.19 mg/kg,定量限分别为1.15、0.47和0.63 mg/kg;总体加标回收率为93.7%~105.8%,相对标准偏差为0.92%~20.60%;以食品安全限量为关注浓度,应用本方法进行合格性快速筛选,Pb、As和Cd含量在关注浓度及以上时阳性检出率为100%,在0.2 mg/kg以下时,假阳性检出率小于等于10%,符合快速检测方法的要求。结论该方法操作简单、快速和绿色无污染,可为食用菌产品的质量控制和检测提供有效的方法借鉴。