| PurposeMinerals are one of the basic substances of human’s life and they are of great use to the health of human beings. Affected by food、geology and environment, the concentration of minerals varies in different areas. Moreover, trace elements play an important role in maintaining body’s physiological function balance and many of them are closely related to health, growth, reproduction and human life, sometimes even endanger human life. People’s requirement for mineral elements, especially essential trace elements, is not dispensable but depends on how much we need. That trace elements supply more than or less than physiological requirements would cause hyper-function or recession of physiological function. However, diseases caused by trace elements do not catch enough attention, but even be ignored or misunderstood. As a result, many tragedies take place without being realized. In fact, each trace element in body has a limit for ideal physiological effects, whether lower or higher than the certain level, it would cause an abnormal physiological function and even lead to serious diseases. In this study, we detect8kinds of mineral elements from children’s hair as follows:calcium, iron, zinc, copper, magnesium, lead, manganese and cadmium, among which calcium and magnesium, the constant elements necessary for human body, since they are closely related to children’s health, this paper will add them to four essential trace elements namely iron, zinc, copper, manganese and two another harmful trace elements which are lead and cadmium for research. The purpose of this research lies in:through the detection of8mineral elements’ concentration, such as calcium, iron, zinc, copper, magnesium, lead, manganese, cadmium by outpatient health check-up for1～6years old children in town of Tanzhou Town, Zhongshan, to study the situation of8mineral elements in children in this region as well as to provide fundamental basis for evaluating the trace elements there, to assess their health level so as to better guide the parents to nurture children scientifically and instruct clinical work on adding nutrients rationally; furthermore, to effectively prevent mineral elements from deficiency or over-standard and to safeguard children’s physical and mental health.MethodTake hair samples from352children who are1～6years old, live scatteredly and receive the outpatient health checks for child health protection from January2011to July2011in town of Tanzhou Town, Zhongshan. With a pair of stainless steel scissors, we cut down hair at0.5-2.0cm from scalp after the occipital as samples that weigh about0.7g, and put them into clear pre-prepared bags for detection. After being soaked in suitable concentration detergent, we wash the hair samples with deionized water and ultrapure water separately and dry them up in a drying oven; Then weigh accurately0.5g hair sample (exactly to0.001g), add4mL HNO3,1mL H2O2to it and dissolve them in microwave digestion; After cooling down, put them into the acid-driven processor and remain for8hours, then cool down again, and bring to volume in a50ml volumetric flask by ultrapure water; with an inductively coupled plasma source mass spectrometer, we determine the contents of these8kinds of mineral elements in the samples (the elements are calcium, iron, zinc, copper, magnesium, lead, manganese and cadmium). Process the data with statistical software such as SPSS13.0and excel2003, analyzing by F test of variance analysis, differences among groups are compared pairwisely with LSD-t test, P<0.05is selected as a significant standard.Before detecting samples in an inductively coupled plasma source mass spectrometer, a standard curve should be configured while testing the precision and accuracy of the experiment. The preparations of standard solution are as follows:Preparation of Mg-Zn mixed stock solution:take500uL1000ug/ml Mg and Zn standard stock solution respectively and bring to volume in a50mL volumetric flask by2%(v/v) HNO3, the concentration is10ug/mL;Preparation of Mn-Cu mixed stock solution:take50uL1000ug/ml Mn and Cu standard stock solution respectively and bring to volume in a50mL volumetric flask by2%(v/v) HNO3, the concentration is1ug/mL;Preparation of Fe stock solution:take50uL1000ug/ml Fe standard stock solution and bring to volume in a50mL volumetric flask by2%(v/v) HNO3, the concentration is1ug/mL;Preparation of Cd stock solution:take5uL1000ug/ml Cd standard stock solution and bring to volume in a50mL volumetric flask by2%(v/v) HNO3, the concentration is0.1ug/mL;Preparation of Pb stock solution:take50uL1000ug/ml Pb standard stock solution and bring to volume in a50mL volumetric flask by2%(v/v) HNO3, the concentration is1ug/mL.Mixed standard solution No.1:in which only purely50mL2%(v/v) HNO3, without Zn, Fe, Cu, Ca, Mn, Pb, Mg and Cd.Mixed standard solution No.2:respectively take Mg-Zn mixed stock solution, Mn-Cu mixed stock solution, Ca standard stock solution, Fe stock solution, Cd stock solution, Pb stock solution each of50uL、0.5ml,50uL,1mL,0.5mL,0.5mL, bring to volume in a50mL volumetric flask by2%(v/v) HNO3.Mixed standard solution No.3:respectively take Mg-Zn mixed stock solution, Mn-Cu mixed stock solution, Ca standard stock solution, Fe stock solution, Cd stock solution, Pb stock solution each of1mL,1mL,100uL,2mL,1mL,1mL, bring to volume in a50mL volumetric flask by2%(v/v) HN03.Mixed standard solution No.4: respectively take Mg-Zn mixed stock solution, Mn-Cu mixed stock solution, Ca standard stock solution, Fe stock solution, Cd stock solution, Pb stock solution each of2.5mL,2.5mL,250uL,5mL,2.5mL,2.5mL, bring to volume in a50mL volumetric flask by2%(v/v) HN03.Mixed standard solution No.5:respectively take Mg-Zn mixed stock solution, Mn-Cu mixed stock solution, Ca standard stock solution, Fe standard stock solution, Cd stock solution, Pb stock solution each of15mL,25mL,1mL,50uL,5mL, lOmL, bring to volume in a50mL volumetric flask by2%(v/v) HNO3.Results1Methodology research for8kinds of mineral elements namely calcium, iron, zinc, copper, magnesium, lead, manganese and cadmium determined in hair with an inductively coupled plasma source mass spectrometer.1.1Methodology research for determination of zinc:the linearity of Zn is favorable, with a standard curve for y=45.716x+156.668, correlation coefficient of r=0.99995, the detection limit at0.18ug/g, quantitative logoff at0.55ug/g, precision RSD at0.36%and standard recovery rate at100.3%.1.2Methodology research for determination of iron:the linearity of Fe is good, with a standard curve for y=67.024x+2150.254, correlation coefficient of r=0.99997, the detection limit at0.14ug/g, quantitative logoff at0.42ug/g, precision RSD at0.81%and standard recovery rate at99.6%.1.3Methodology research for determination of copper:the linearity of Cu is good, with a standard curve for y=64.655x+25.556, correlation coefficient of r=0.99992, the detection limit at0.04ug/g, quantitative logoff at0.13ug/g, precision RSD at4.2%and standard recovery rate at101%.1.4Methodology research for determination of calcium:the linearity of Ca is good, with a standard curve for y=8.366x+691.693, correlation coefficient of r=0.99986, the detection limit at2.0ug/g, quantitative logoff at6.1ug/g, precision RSD at0.66%and standard recovery rate at97.0%.1.5Methodology research for determination of manganese:the linearity of Mn is good, with a standard curve for y=514.330x+40.000, correlation coefficient of r=0.99987, the detection limit at0.14ug/g, quantitative logoff at0.41ug/g, precision RSD at2.16%and standard recovery rate at100.3%.1.6Methodology research for determination of lead:the linearity of Pb is good, with a standard curve for y=488.148x+108.890, correlation coefficient of r=0.99993, the detection limit at0.027ug/g, quantitative logoff at0.08ug/g, precision RSD at0.77%and standard recovery rate at96.6%.1.7Methodology research for determination of magnesium:the linearity of Mg is good, with a standard curve for y=93.698x+103.334, correlation coefficient of r=0.99995, the detection limit at0.075ug/g, quantitative logoff at0.226ug/g, precision RSD at0.21%and standard recovery rate at100.3%.1.8Methodology research for determination of cadmium:the linearity of Cd is good, with a standard curve for y=103.940x, correlation coefficient of r=0.99970, the detection limit at0.0008ug/g, quantitative logoff at0.0023ug/g, precision RSD at5.26%and standard recovery rate at95%.2The results of sample measurements are as follows:2.1Zinc, iron, copper and calcium contents are out of balance in different degrees. 2.2All of the mineral elements have deficiency or excess in different degrees. Among the four elements as zinc, iron, copper and calcium, the detection rate of calcium deficiency is the highest, which is up to45.17%, followed by copper17.09%, zinc16.48%, iron16.19%. On the whole, the detection rate of deficiency reduces as the growth of ages, while the detection rate of zinc excess is the highest, which is up to53.13%, followed by iron38.64%, copper20.74%, the detection rate of excess generally rises with the ages increasing.2.3According to the F test, the detection results of8mineral elements, which come from352children aging from1to6years old, show that there is a statistical significance in the difference of ages when testing zinc, magnesium and cadmium (P=0.00, P=0.015, P=0.022) while there is not in testing iron, copper, calcium, manganese and lead(P>0.05). The LSD pair-wise comparison results:Except for group1and group2, group3and group4, group5and group6, other pairs of zinc have a statistical significance; besides, statistical significance exists between group2and group5of magnesium and cadmium.Conclusion1Calcium deficiency is ordinary:in addition to building bone in the body, calcium still plays a role as activator of many metabolic enzymes. It plays an important role in maintaining muscle, nerve excitement and enzyme activation. As we can see from the result, generally there is calcium deficiency in all ages, especially in a lower age, but there is also a little bit high rate of calcium deficiency in a high age. In this region, the level of calcium nutrition is low, which indicates that the intake of calcium nutrient in all ages is poor and needs to strengthen the guidance, to increase children’s outdoor activities and exposure to the sun, to add vitamin D and calcium supplement timely and reasonably, etc. 2Zinc imbalance is in a heavier level:Zinc is an important element for people. It can not only take part in the synthesis of nucleic acid and protein, but also act as prosthetic group of enzyme and in this way it can promote the smooth metabolism of all kinds of nutrients and stimulate the growth and development of skin, bone and sexual organs. In this research, zinc deficiency in children, especially obvious in low ages, relatively improving in high ages. On the contrary, with the ages growing, the excess rate of zinc becomes higher and higher, totally it can be up to53.13%.3There is comparatively heavy imbalance in iron:Iron can compose hemoglobin, involve in the combination of hormone synthesis or enhance the effect of hormone and maintain the body’s normali mmune function,compose myohemoglobin, etc. Showed by the test results, iron deficiency rate likewise concentrates in the low age group and turns up the same as zinc; excessive rate is comparatively high, which is up to38.64%and higher than the deficiency rate.4The result of Copper does not allow optimism:Copper and ceruloplasmin have both enzyme activity and the oxidative activity. They can strengthen body’s defense. This result shows that the deficiency rate and excess rate of copper are inhomogeneous. There are both excess and deficiency while the excess rate still remains high. Among low age children, the deficiency rates of mineral elements such as zinc, iron and copper are outstanding. Yet the deficiencies of zinc, iron, copper in high age children also do not allow ignorance, which reminds that we should focus on strengthening health care management in all ages especially among1～4years old preschool period children. There is a more special case emerging in this region, the excess rate of zinc, iron, copper is comparatively higher than that of others’, especially zinc and iron, whose excess rates are much higher than deficiency rates, which gives a hint that parents in this region may be misled by advertising and consequently add mineral elements to children’s diet blindly. In order to ensure a balanced nutrition supply to children, we advise that parents add all kinds of mineral elements rationally and reasonably.5The results of manganese should be viewed with caution:Manganese is a component of enzymes, playing a role in maintaining the normal development of bones, promoting the metabolism of sugar and fat as well as antioxidation. Indicated in this study, manganese deficiency is in a heavier level, the rate is up to64.20%, as body’s requirement of manganese can be satisfied through the normal diet, generally the deficiency will not happen, so this kind of contradiction’s appearance may be related to the set of reference, different instruments and equipments used in this research. At present, there is no reliable biological indicators1for nutrition assessment of manganese, which may also explain why the test result is subnormal. Consequently, we should hold a cautious attitude towards the manganese deficiency.6Lead and cadmium’s testing results are acceptable:Lead is a systematically toxic element and is extremely harmful to human body. It can affect multiple systems, thus its bad influence can be found in the nerve system, motor system, digestive system,reproductive system,immune system,cardiovascular system, hematopoietic system, urinary system and the endocrine system. Up to now, cases of lead poisoning have occurred in many developing countries. Children are highly sensitive to lead exposure, lead concentrations of children below6years old in this region are all within the normal range. No case of excess had been found, the content is obviously lower than the national level of51.6%. Cadmium is not one of the essential elements in oneself body but is accumulated from the external environment. Cadmium contents detected from children’s hair in the region are all below reference values, which indicate the living environment there is good. Although the inspection result is satisfactory, with the solid industrial foundation, the region is regarded as one of the first towns with prosperous industry and strong economy in the city. So we cannot take this result slightly. Moreover, parents and government should take this problem seriously. All walks of life should join together and take their participations, ensuring that citizens have a good environment free from pollution. The last but not the least, for children’s medical and health institutions, lead detection in children’s hair or blood should be widely carried out and actively advocated. In order to detect early, to intervene early and to prevent lead poisoning, children and parents should receive targeted health education. |
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