铅锌矿区居民头发中Pb，As，Cd等有害元素含量、微区分布及元素形态特征研究

头发是人体元素的排泄器官之一，头发中元素含量能反映出一段时间内矿区毒性元素在人体内的吸收和代谢情况。采用电感耦合等离子体质谱(ICP-MS)和电感耦合等离子体原子发射光谱(ICP-OES)对某铅锌矿区居民头发中Pb，As，Cd，Ca，Mg，Fe，Zn，Cu，Mn和Sr进行了定量分析，应用微区X射线荧光(Micro-XRF)和X射线吸收近边结构谱(XANES)测定了头发中的Pb和As等元素微区分布和Pb形态。研究发现(1)当地部分居民已经受到矿区中Pb，Cd，Cu和Mn等重金属污染的危害。(2)不同性别群体的生理特征和生活习惯是决定其分布特征的主要因素，其中女性头发中Pb，Cd，Ca，Mg，Zn，Cu和Sr的平均含量都显著高于男性，男性头发中的Fe显著高于女性；(3)由于各元素性质、来源和吸收机制等原因，矿区居民头发中Ca-Mg-Sr-Zn，Pb-Cd-Cu-Mn，Fe-Mn具有相关性；(4)矿区典型头发样本中Pb和As主要沿头发中轴分布，从发根至发梢含量有逐渐增多的趋势；(5)头发样品中Pb由4.7%Pb₃(PO₄)₂，36.8%Pb-GSH和8.4%PbS组成；(6)头发中不溶性磷酸铅、铅-半胱氨酸巯基结合态是发铅的主要存在形态，揭示了其为人体铅代谢的主要途径之一。

Quantitative Analysis,Distribution and Speciation of Elements as Pb,As, Cd in Human Hair from Inhabitants in a Lead-Zinc Mining Area

Hair is one of the excretion organs in human body, so the element content in hair can reflect human body exposure to the toxic elements in the vicinity of the mining area in a period. Pb, As, Cd, Ca, Mg, Fe, Zn, Cu, Mn and Sr in hair sampels collected from a lead-zinc mine were analyzed quantitatively with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES). Micro X-ray fluorescence(Micro-XRF) and X-ray absorption near edge structure(XANES) were used to determine element distribution of Pb, As and speciation of Pb, respectively. The study revealed that (1) The average contents Pb, Zn, Fe, Ca(female) and Mn(male) in the hair sampels were 1.2 times, 1.3 times, 3.9 times, 1.6 times and 1.2 times higher than the normal values, respectively. (2) It was confirmed that The toxic elements in the mining area can be transferred to human beings through the food chain and may causeeventually serious health problems. In addition, different physiological features and living habits were main factors that determined the metal distribution in the different gender groups. Those restuls in that Pb, Cd, Ca, Mg, Zn, Cu and Sr in female were significantly higher than those in male while Fe was in male higher than that in femail. (3) As a result of elements properties, sources and absorption mechanismthere was a positive correlation between Ca-Mg-Sr-Zn, Pb-Cd-Cu-Mn and Fe-Mn respectively. (3) Micro-XRF mapping showed that Pb and As were mainly distributed along the hair axis. Horizontally, the concentration gradient of Pb and As plunge from inside to outside. Because daily cleaning and wearing will lead to peeling of Pb and As which were not closely tied. Longitudinally, there was an increasing trend of Pb and As from hair root to hair tip. We speculated that Pb and As unite with cysteine of keratin in cortex. The vertical distribution characteristics of Pb and As reflected the change of external environment which residents exposed to. (4) On the basis fo XANES analysis, lead in the collected hair sample was composed of 54.7% lead phosphate, 36.8% Pb-glutathione and 8.4% lead sulfide. (5) The main lead speciation in hair were insolubility lead phosphate and sulfur-bounding speciation like Pb-cysteine, suggesting that hair is one of the main way to metabolise lead. To our knowledge, this is the first report on the speciation of Pb in the human hair from lead-zinc mining area.