锰元素体内平衡的营养状况

锰是人体必需的矿物质。实际上,锰在各种食物中的含量很低。锰元素的主要摄入途径是膳食摄入,但是在某些特定职业人群中,也可能发生吸入性暴露。人体通过对吸收和排泄的稳态控制来维持锰元素在组织中的浓度稳定。尽管如此,经口与非经口接触高浓度锰,或者暴露在高锰空气环境中会导致组织中锰浓度升高。在中枢神经系统过量的锰蓄积在临床上被称为锰中毒。锰中毒在临床症状上与原发性帕金森症很相似,会对实验动物和人体造成神经系统的损害。现就目前相对研究较少的领域,即接受肠外营养的新生儿对营养液中高浓度锰的暴露有可能增加他们患锰离子诱导健康后遗症的风险进行介评。     

广东境内地面水中锰含量调查

广东境内地面水中锰含量调查董胜璋，蔡承铿，黎大明，陈婉颜，兰兴华锰是人体必需的微量元素，饮水中锰及其化合物含量高低可直接影响人体对锰的摄入量。水中锰含量超过一定浓度时又会影响水的色、嗅、味等感官性状和水自净作用。为了解地表水中锰含量，我们对广东境内主...     

锰暴露区儿童头发微量元素调查

目的了解锰污染区儿童头发中微量元素含量的变化。方法整群抽取太原市城南40 km清徐县及城北30 km尖草坪区四、五年级学生各200名,作为暴露组和非暴露组。进行一般情况的调查,并采用火焰原子吸收法测定头发中微量元素（钙铁锌锰）,并对结果进行统计分析。结果暴露组发锰平均含量与发锌平均含量明显高于非暴露组,差异有统计学意义（P〈0.05）。暴露组儿童发锰平均含量高于北方农村儿童发锰含量,差异有统计学意义（P〈0.05）;非暴露组儿童发锰平均含量与北方农村儿童发锰含量差异无统计学意义（P〉0.05）。暴露组中,独生与非独生子女发锰平均含量差异无统计学意义（P〉0.05）;女生发锰及发钙平均含量高于男生,差异有统计学意义（P〈0.05）。结论暴露组儿童发锰含量增高,其中女生更为显著。     

火焰原子吸收光谱法测定茶叶中的锰

锰是人体必需的微量元素之一,但锰摄入人体的量蓄积到一定程度会导致慢性神经中毒.茶叶中锰含量相当高,在国家茶叶卫生标准中,没有规定锰的限量标准和测定方法,因此准确测定茶叶中锰的含量很有必要,用火焰原子吸收光谱法测定茶叶的锰,操作简便、精密度和准确度好,结果令人满意.     

石墨炉原子吸收光谱法直接测定血清中痕量锰

锰是人体必需的微量元素，虽然在体内含量很小，但对于人体的营养和功能却有很大影响。但过量的锰会造成锰中毒。锰中毒对脑组织的损坏较大，同时还影响体内胰岛素和糖代谢旧。。因此对体内锰含量的测定具有重大意义。本文在文献”。的基础上，探讨了石墨炉原子吸收光谱法直接测定血清中痕量锰，该法由于灵敏度高，取样量少，很适用于生物样品的分析。     

环境锰暴露与儿童神经行为的关系

正锰是人体的必需微量元素,不仅参与蛋白质和脂肪代谢所需酶的构建,还用于体内多种酶的激活及神经递质传递的调节,对人体的生长发育、维持正常功能活动起着非常重要的作用。如果锰摄入过量,会在脑部蓄积,产生神经毒性作用。由于职业人群空气锰接触浓度高,健康危害效应容易检出,关于锰暴露健康影响的研究绝大多数围绕职业锰接触开展。除了职业接触外,锰矿石的开采冶炼、含锰产品的使用以及锰元素富集的地     

职业锰暴露水平与指甲中锰含量关系的研究

目的研究职业锰暴露水平与指甲中锰含量的相关性,探讨指甲中锰含量作为早期生物接触标志物监测指标的可行性。方法选择工龄1a的接触职业性有害因素锰的电焊作业人员作为暴露组,选择在通州区辖区内在当地居住3a以上的在职医务人员作为对照组;用不锈钢指甲刀采集每个研究对象的指甲,每份重量在0.1g以上。用个体采样器对暴露组进行个体空气样品采集,用火焰原子吸收光谱法测定职业锰暴露水平,用电感耦合等离子体质谱法(ICP-MS)测定指甲中锰含量。结果暴露组的指甲锰含量(1.345~59.584μg/g,P50=10.532)明显高于对照组的指甲锰含量(0.325~1.970μg/g,P50=0.854),两组比较,差异有统计学意义(u=28,P0.05);职业锰暴露水平与指甲中锰含量之间有相关性(r=0.479,P0.01)。结论暴露组随着锰接触水平的增高,指甲锰含量有明显上升的趋势。职业锰暴露水平与指甲中锰含量有相关性,指甲中锰含量可作为作业环境锰暴露水平、职业健康监护、锰中毒诊断的早期生物接触标志物监测指标。     

职业性锰暴露对男性工人血浆脑源性神经营养因子含量的影响

[目的]通过测定职业性锰暴露男性工人血浆脑源性神经营养因子(BDNF)水平,探讨锰暴露对工人血浆BDNF含量的影响. [方法]选择广西某锰冶炼厂179名男性工人为暴露组,按锰累积暴露指数(CEI)分为低暴露组(CEI＜2.000,84名)和高暴露组(CEI≥2.000,95名),以同一地区某糖厂96名男性工人为对照组,对其进行一般情况调查和血浆BDNF含量的测定. [结果]控制年龄、民族等协变量后,该厂锰作业男性工人CEI与血浆BDNF含量呈负相关(r=-0.200,P＜0.05);两个暴露组人群血浆BDNF含量均低于对照组工人(均P＜0.01),高暴露组工人低于低暴露组(P＜0.05). [结论]职业性锰暴露可降低锰冶炼厂男性工人的血浆BDNF水平.     

微量元素锰的代谢

<正> 1931年,Kemmerer 和 Orent 等首先提出,饲料中含有一定的锰对动物(大鼠、小鼠)的生长、发育是必需的。后来又证实,缺锰大鼠的子代在哺乳期死亡率高。因而锰早已被列为对人体及动、植物所必需的微量元素之一。本文拟就锰在人体及动物体内有代谢作一综述。一、锰的吸收食物中锰的含量变化很大。Wenlock 等(1979)报道,锰含量较高的有坚果、谷类及     

锰健康研究的现状和未来研究

锰是人体必需的重要元素,然而暴露在高剂量的情况下,锰与某些有害健康的效应有关,尤其与中枢神经系统有关.锰暴露程度与地理位置、城市或乡村环境、生活方式、饮食、工作环境有很大的关系.此外,暴露时间可能是短暂的或是长期的,可能是不同类型的锰化合物(气溶胶或不同物理和/或化学特性的锰盐),可能发生在不同的生命期(胎儿期、新生儿期、青春期、成年期或衰老期),伴随不同的遗传因素,这些因素反应了个体对锰的暴露可能有着不同程度的敏感性.锰也是一种重要的金属,被广泛应用到工业生产中.而在锰应用的领域中,存在许多关于锰对健康潜在危害性的讨论.由此,有必要联合各方进行相关研究,以此准确判定锰对健康的影响,从而制定合理的预防措施.     

Sensitivity of water tupelo (Nyssa aquatica) and bald cypress (Taxodium distichum) seedlings to manganese enrichment under water-saturated conditions

In anaerobic soils of wetlands, Mn is highly available to plants because of the decreasing redox potential and pH of flooded soil. When growing adjacent to each another in wetland forests, water tupelo (Nyssa aquatica L.) had 10 times greater leaf manganese concentration than bald cypress (Taxodium distichum [L.] Richard). This interspecific difference was examined over a range of manganese-enriched soil conditions in a greenhouse experiment. Water tupelo and bald cypress seedlings were grown in fertilized potting soil enriched with 0, 40, 80, 160, 240, 320, and 400 mg Mn/L of soil and kept at saturated to slightly flooded conditions. Leaf Mn concentration was greater in water tupelo than bald cypress for all but the highest Mn addition treatment. Growth of water tupelo seedlings was adversely affected in treatments greater than 160 mg Mn/L. Total biomass of water tupelo in the highest Mn treatment was less than 50% of the control. At low levels of added Mn, bald cypress was able to restrict uptake of Mn at the roots with resulting low leaf Mn concentrations. Once that root restriction was exceeded, Mn concentration in bald cypress leaves increased greatly with treatment; that is, the highest treatment was 40 times greater than control (4,603 vs 100 microg/g, respectively), but biomass of bald cypress was unaffected by manganese additions. Bald cypress, a tree that does not naturally accumulate manganese, does so under manganese-enriched conditions and without biomass reduction in contrast to water tupelo, which is severely affected by higher soil Mn concentrations. Thus, bald cypress would be less affected by increased manganese availability in swamps receiving acidic inputs such as acid mine drainage, acid rain, or oxidization of pyritic soils.     

Distribution of Arsenic and Trace Metals in the Floodplain Agricultural Soil of Bangladesh

Arsenic contaminated groundwater of Bangladesh is one of the largest natural calamities of the world. Soil samples were collected from floodplain agricultural land of Faridpur and Dhamrai regions to estimate the concentration of arsenic and other trace metals (copper, nickel, zinc, chromium, cadmium, lead, selenium, cobalt, mercury, and manganese). Average arsenic in Faridpur soil was recorded more than three times higher than the world limit and nearly five times higher than that of Dhamrai. The average copper, chromium and cobalt both in Faridpur and Dhamrai agricultural soil were also higher than the Dutch and the world standards. Both Fardipur and Dhamrai soil contain low amount of selenium in comparison to world limit (0.7 mg kg⁻¹). A poor correlation between manganese and arsenic was noticed in Faridpur. This may be played a subordinate role in the fixation of arsenic in soil. This study also reveals that the area which has arsenic and trace metal contaminated groundwater may also contain high level of arsenic and trace metals in the agricultural soil due to irrigation with contaminated groundwater.     

2015—2019年内蒙古地区饮用水铁、锰水平及影响因素

目的 调查内蒙古地区饮用水中铁、锰水平,对影响饮用水中铁、锰合格情况因素进行探索,为饮用水改水工作提供依据.方法 于2015—2019年连续检验内蒙古地区城乡饮用水水质,观察铁、锰指标变化情况,对饮用水中铁、锰污染情况评价和分析.结果 内蒙古地区连续5年铁和锰的达标率差异均有统计学意义(χ2分别是60.00、66.55...     

Blood manganese concentrations among first-grade schoolchildren in two South African cities

Little information exists on the environmental exposures to low levels of organometallic manganese (a principal combustion product from manganese-containing fuel additives) and public health. This study was undertaken to establish biological and environmental levels of manganese among first-grade schoolchildren in the South African cities of Johannesburg and Cape Town. The study was undertaken subsequent to partial introduction of the manganese-containing fuel additive methylcyclopentadienyl manganese tricarbonyl (MMT) to South African petrol in the Johannesburg region only, about 24 months prior to the commencement of the study, and in anticipation of possible future increases in MMT use in the rest of the country. This study involved the measurement of manganese concentrations in the blood of the total number of 814 of grade one schoolchildren (430 and 384 in Cape Town and Johannesburg, respectively), and in water supplies, soil, and classroom dust at a total number of 21 participating schools. The results indicated higher concentrations of manganese in school soil (P=0.0007) and dust (P=0.0071) samples from Johannesburg relative to Cape Town. Similarly, the mean blood manganese concentration in Johannesburg study subjects (9.80 microg/L, SD 3.59) was significantly higher than that in Cape Town study subjects (6.74 microg/L, SD 3.47), after allowing for the clustering effect within schools and adjusting for the confounding effect of population group (P<0.0001). The blood manganese levels of 4.2% and 12.5% of children in Cape Town and Johannesburg, respectively, equaled or exceeded 14 microg/L, the upper normal reference value specified by the Agency for Toxic Substances Disease Registry (ATSDR, 2000). Importantly, levels of manganese in blood were found to be significantly associated with concentrations of manganese in classroom dust at schools.     

Manganese and copper imbalance in the food chain constituents in relation to Creutzfeldt-Jakob disease

The objective of the study was to investigate the possible role of manganese and copper (Mn/Cu) imbalance of the food chain in the focally increased occurrence of Creutzfeldt-Jakob disease (CJD). Mn and Cu concentrations in soil, drinking water and foodstuffs collected from households in the region of focal accumulation of CJD patients and the control region were measured by FAAS. Considerably higher Mn/Cu ratios in the studied region than those in the control region were found for soil (49.3 vs. 21.1), honey (8.05 vs. 4.86), and for the main local food items: potatoes (2.09 vs. 1.07) and bread (5.85 vs. 5.35), however, only soil and potatoes were of statistical significance. The results could indicate a rare coincidence of the verified endogenous CJD risk (genetic) with a very probable exogenous CJD risk factor (Mn/Cu dietary/environmental imbalance), but whether and how this coincidence may contribute to the unique, continual temporo-spatial clustering of genetic CJD should be investigated in further studies.     

临桂县农村生活饮用水卫生现状及防治对策

目的摸清临桂县农村生活饮用水卫生状况,找出问题的产生原因,指导防治对策的制订。方法采集地表水、地下水、山泉水样本33份,进行微生物学检验及铁、锰等金属元素检测。结果33份水样微生物指标均超过三级水的标准,不合格率为100％,有两份采自硫铁矿附近的水样铁、锰含量超标。结论治理水源污染,对供水进行净化消毒是保证临桂县农村饮用水卫生的当务之急和有效方法。     

Exposure to manganese: health effects on the general population, a pilot study in central Mexico

To support a risk assessment of manganese exposure in two communities living within a manganese mining district a cross-sectional study was performed on a sample of the adult population of long-term residents. One community was exposed to a point source from an ore primary refining plant. Manganese is an essential mineral for human life. It is also the fourth in importance for industrial metal making. Data were collected on socioeconomic living conditions, emission sources, environmental media concentrations (air, water, soil, dust, food), respiratory symptomatology, and a neuropsychological examination (Mini-Mental Screening test, the Hooper Visual Organization test, the Ardila-Ostroski, and others). We examined 73 subjects (52 women), most of low socioeconomic status. Environmental air concentrations were 2 to 3 times higher than those in other urban concentrations. Manganese blood concentrations ranged from 7.5 to 88 microg/L, with a median concentration of 15, the upper quartile starting at 20 microg/L; the upper 10% was above 25 microg/L. Lead and manganese were highly correlated; there was an inverse relation to hemoglobin. Reduced levels of plasma lipid peroxidation were associated with blood manganese. Using multivariate logistic regression, we identified B-Mn as increasing the risk of deficient cognitive performance 12 times (Mini-Mental score of less than 17).     

Chronic exposure of sheep to a zinc smelter in Peru

Liver levels of arsenic, cadmium, copper, lead, manganese, and zinc were assessed in adult female sheep living in the vicinity of a zinc smelter in Peru. The study was conducted on a large sheep-raising cooperative divided into seven management units, operated under a standardized husbandry system. Soil samples were analyzed for the same metals at varying distances from the smelter. A gradient of concentration of heavy metals in soil was found between 1 and 56 km from the smelter. Soil concentrations for all metals except manganese decreased significantly with increasing distance from the smelter. The strongest correlations were found for copper, lead, and zinc (P less than 0.001). Topographic features and prevailing wind direction appeared to play a role in the dispersion of pollutants. Liver samples were obtained from 153 sheep on five units of the cooperative. The centers of the units sampled were between 13 and 56 km from the smelter. Hepatic concentrations of arsenic, lead, manganese, and zinc decreased significantly with increasing distance from the smelter. Liver arsenic and liver zinc were significantly related to soil concentrations. Liver levels of arsenic, cadmium, lead, and manganese in sheep from the cooperative were significantly higher than those detected in control sheep from southern Peru. Sheep populations may serve as biological monitors for heavy metal accumulation and environmental carcinogenesis.     

Metal sources and exposures in the homes of young children living near a mining-impacted Superfund site

Children living near hazardous waste sites may be exposed to environmental contaminants, yet few studies have conducted multi-media exposure assessments, including residential environments where children spend most of their time. We sampled yard soil, house dust, and particulate matter with aerodynamic diameter <2.5 in 59 homes of young children near an abandoned mining area and analyzed samples for lead (Pb), zinc (Zn), cadmium (Cd), arsenic (As), and manganese (Mn). In over half of the homes, dust concentrations of Pb, Zn, Cd, and As were higher than those in soil. Proximity to mine waste (chat) piles and the presence of chat in the driveway significantly predicted dust metals levels. Homes with both chat sources had Pb, Zn, Cd, and As dust levels two to three times higher than homes with no known chat sources after controlling for other sources. In contrast, Mn concentrations in dust were consistently lower than in soil and were not associated with chat sources. Mn dust concentrations were predicted by soil concentrations and occupant density. These findings suggest that nearby outdoor sources of metal contaminants from mine waste may migrate indoors. Populations farther away from the mining site may also be exposed if secondary uses of chat are in close proximity to the home.     

Iron plaque formation on roots of different rice cultivars and the relation with lead uptake

The relationships between lead (Pb) uptake and iron/manganese plaque formation on rice roots were investigated with three cultivars. The results showed that the rice cultivars with indica consanguinity were more sensitive to soil Pb stress than the cultivar with japonica consanguinity. Pb concentrations and distribution ratios in root tissues were in the order: Shanyou 63>Yangdao 6>Wuyunjing 7, but Pb and Fe concentrations and distribution ratios in the plaques showed a reverse order. Mn concentrations and distribution ratios in the plaques of Wuyunjing 7 were significantly higher (P<0.01 or 0.05) than those of Shanyou 63 and Yangdao 6. The results indicate that iron/manganese plaque on rice root can provide a barrier to soil Pb stress. The plaque will increase sequestration of Pb on rice root surface and in the rhizosphere, providing a means of external exclusion of soil Pb to some extent.