Mercury, cadmium, and lead levels in human placenta: a systematic review

Background: Placental tissue may furnish information on the exposure of both mother and fetus. Mercury (Hg), cadmium (Cd), and lead (Pb) are toxicants of interest in pregnancy because they are associated with alterations in child development.Objectives: The aim of this study was to summarize the available information regarding total Hg, Cd, and Pb levels in human placenta and possible related factors.Methods: We performed a systematic search of PubMed/MEDLINE, EMBASE, Lilacs, OSH, and Web of Science for original papers on total Hg, Cd, or Pb levels in human placenta that were published in English or Spanish (1976-2011). Data on study design, population characteristics, collection and analysis of placenta specimens, and main results were extracted using a standardized form.Results: We found a total of 79 papers (73 different studies). Hg, Cd, and Pb levels were reported in 24, 46, and 46 studies, respectively. Most studies included small convenience samples of healthy pregnant women. Studies were heterogeneous regarding populations selected, processing of specimens, and presentation of results. Hg concentrations > 50 ng/g were found in China (Shanghai), Japan, and the Faroe Islands. Cd levels ranged from 1.2 ng/g to 53 ng/g and were highest in the United States, Japan, and Eastern Europe. Pb showed the greatest variability, with levels ranging from 1.18 ng/g in China (Shanghai) to 500 ng/g in a polluted area of Poland.Conclusion: The use of the placenta as a biomarker to assess heavy metals exposure is not properly developed because of heterogeneity among the studies. International standardized protocols are needed to enhance comparability and increase the usefulness of this promising tissue in biomonitoring studies.     

胎儿期汞暴露对新生儿神经行为发育影响

  目的  调查普通孕妇不同孕期外周血及新生儿脐带血红细胞中甲基汞浓度变化及相关性。  方法  于2019年1 — 4月在湖北省武汉市招募79名孕妇,采集孕妇孕早期[孕（12 ± 2）周]和孕晚期[孕（37 ± 2）周]外周血及新生儿脐带血,分离红细胞,采用高效液相色谱 – 电感耦合等离子体质谱联用方法检测红细胞内甲基汞浓度。  结果  本研究孕妇孕早、晚期及脐带血红细胞中甲基汞浓度的几何均数分别为0.322、0.238、0.515 μg/g,四分位数间距分别为0.188～0.728、0.120～0.549、0.322～1.099 μg/g,孕早期甲基汞含量显著高于孕晚期（P < 0.05）,孕晚期甲基汞含量显著低于脐带血（P < 0.05）,孕早期甲基汞含量也显著低于脐带血（P < 0.05）,孕早、晚期血及脐带血甲基汞含量之间两两呈现强正相关性（r = 0.763、0.866、0.854）。  结论  孕妇孕早期、孕晚期血和新生儿脐带血红细胞中甲基汞含量存在明显相关性;脐带血红细胞甲基汞含量显著高于孕妇外周血,提示可能存在富集现象。     

围产儿的围产因素与胎盘病理改变的关系探讨

对１９９５年７月在我院分娩２４４例产妇胎盘病理检查结果显示，胎盘病理炎症改变与新生儿肺炎、羊水混浊间有着显著性差异（Ｐ＜０．０５）；而与胎膜早破、胎盘功能低下、宫内窘迫、ＳＧＡ、新生儿窒息等的发生无显著性差异（Ｐ＞０．０５）。提示当胎盘病理检查检出炎症，或发生羊水混浊者，都应高度警惕围产儿感染的发生，及早采取预防感染的措施，以提高围产儿质量。     

The effect of a lindane and mercury polluting incident on the health of a community: The Somerton Health Survey

Objectives: This study sought to identify possible illnesses of people exposed to lindane and methyl mercury following a pollution incidence in Somerton, Somerset, UK.Methods: A self-administered questionnaire survey was posted to 1500 residents in three selected areas of Somerton to identify symptoms of possible illnesses over a 3 month period.Results: There was a 74% response rate. People living near the stream had higher levels of reported mental symptoms and itching skin than in controls. Poisoning as the cause of the mental symptoms was excluded as the individuals had normal blood levels of lindane or mercury. Other symptoms were no higher in one area than another or from one time period to another.Conclusions: The survey, using controls in time and space, was able to explore, the pollution incident's contribution to the toxicity of residents and how this related to mental symptoms experienced by the residents.     

Fish consumption patterns,knowledge and potential exposure to mercury by race

Objective: Compared fish consumption patterns, fish advisory/benefit awareness and risk factors of consuming high-mercury (Hg) fish between Chinese and non-Chinese adults. Methods: 301 Chinese and 120 non-Chinese participated in this cross-sectional study. Participants self-reported demographics, fish consumption behavior, and awareness of warnings/benefits of fish consumption. Results: non-Chinese (62.5%) ate more high-Hg fish than Chinese (35.9%) although more Chinese ate fish in the last year. Over 90% of both groups knew general benefits of consuming fish; fewer knew specific benefits. Chinese were less aware of fish warnings (49.8%) than non-Chinese (86.7%); knowledge did not appear to affect their fish consumption. Conclusions: There were significant differences in fish consumption patterns and fish benefit/warning knowledge between the two groups. A higher proportion of non-Chinese reported consumption of high-Hg fish. Fish knowledge did not affect fish consumption behavior for either group. Public education efforts regarding fish consumption should emphasize details such as species and amounts.     

环境和饲料中的镉对畜禽的毒性研究进展

大量研究表明,饲料中的镉超标会对畜禽机体的肾脏、骨骼等部位产生一系列的毒害作用。从环境、饲料和动物体中镉的来源入手,综述了镉在动物体内的代谢,镉对畜禽的毒性及机理,镉与其它元素的交互关系,畜禽镉中毒的防治对策,并对这一研究领域的发展趋势进行了讨论。     

亚硒酸钠对镉和汞肝肾氧化损伤影响的实验研究

目的:观察一次染镉和汞对大鼠肝、肾组织氧化损伤作用,探讨亚硒酸钠预处理对镉和汞氧化损伤的影响。方法:Wister大鼠48只,随机分成6组,每组8只,第1组为染镉实验对照组,第2组为单纯染镉组,第3组为亚硒酸钠预处理组,第4组为染汞实验对照组,第5组为单纯染汞组,第6组为亚硒酸钠预处理干预组。第1、4组大鼠先腹腔注射生理盐水,2 h后皮下注射生理盐水。第2组大鼠先腹腔注射生理盐水,2 h后皮下注射35μmol/kg氯化镉溶液。第3组大鼠先腹腔注射10μmol/kg亚硒酸钠溶液,2 h后皮下注射35μmol/kg氯化镉溶液。第5组大鼠先腹腔注射生理盐水,2 h后皮下注射2.5 mg/kg HgCl2溶液,第6组大鼠先腹腔注射20μmol/kg亚硒酸钠溶液,2 h后皮下注射2.5 mg/kg HgCl2溶液。染毒24 h后测定肝、肾皮质镉或汞、谷胱甘肽、丙二醛含量和谷胱甘肽过氧化物酶活性。结果:与对照组比较,单纯染镉组大鼠肝GSH、MDA含量显著升高,GSH—Px活性显著下降。Na2SeO3预处理组肝、肾皮质GSH和镉含量显著降低,肝脏GSH—Px活性及肾皮质MDA含量显著升高。单纯染汞组大鼠肝、肾皮质及尿汞含量均显著高于对照组。单纯染汞组肝MDA含量显著高于对照组,GSH含量和GSH—Px活性显著低于对照组。Na2SeO3预处理组的肝脏GSH含量和GSH—Px活性均较单纯染汞组升高,有显著性差异。单纯染汞组肾皮质MDA含量显著高于对照组,GSH含量和GSH—Px活性显著降低。Na2SeO3预处理组中肾皮质MDA含量低于单纯染汞组,GSH—Px含量高于单纯染汞组。结论:给大鼠一次染镉和汞,可以对肝和肾脏产生明显的氧化损伤作用。亚硒酸钠对急性染镉和汞所致肝肾损伤具有一定的拮抗作用,其机制可能与增加内源性GSH、使GSH—Px活性增强以及清除自由基能力提高有关。     

Biological monitoring of metals in children and pregnant women in Poland

A pilot study was carried out on the concentration of cadmium, lead, mercury and selenium in blood and urine from 15 first grade school children, 7–8 years of age, living in Katowice‐Szopienice (Silesian Region), and eight pregnant women living in Krakow. The two Polish communities have high levels of pollution from the metallurgic and coal industry. The concentrations of lead in blood for the children ranged from 77 to 255 µg Pb 1^?1 with a median (Md) of 163 µg Pb 1^?1 and for the women from 32 to 64 µg Pb 1^?1 with a Md of 38 µg Pb 1^?1 The high lead levels in blood among the children were related to the distance from their home to a smelter. The analysis of lead in urine also identified the children with the highest levels of exposure. The median levels of cadmium in blood were for children 0.5 µg Cd 1^?1 and for women 0.7 µg Cd 1^?1 and in urine 0.4 µg Cd 1^?1 for children and 0.5 µg Cd 1^?1 for women. Mercury levels in blood were below 4 µg Hg 1^?1 in both groups. The concentrations of selenium in plasma and blood were low and for children the range in blood was 57 to 79 µg Se 1^?1 with a Md of 64 µg Se 1^?1. The selenium in blood for the pregnant women ranged from 30 to 86 µg Se 1^?1 with a Md of 50 µg Se 1¹.     

前置胎盘的流行病学特征及其期待疗法

目的 了解前置胎盘的流行病学特征及期待疗法对围产儿预后的影响。方法 对1992年1月-2002年12月收治的226例前置胎盘患者的病史采集及住院观察。结果 收治住院孕产妇总数为17610例，其中前置胎盘226例，其发生比例为1．28%；胎盘异常85例，占前置胎盘分娩总数的40．86％;流、引产次数与妊娠次数越多，前置胎盘发生率越高；通过期待疗法，尽量延长孕龄，降低了低出生体重儿的发生率。结论 预防前置胎盘的发生从根本上就应减少宫腔手术史；前置胎盘在无明显大出血及并发症情况下，能尽量期待至37周以上再予以分娩为佳.     

Reference intervals of cadmium,lead, and mercury in blood,urine, hair,and nails among residents in Mansoura city,Nile delta,Egypt

A random sample of 68 males and 25 females who reside in Mansoura city, Egypt, was examined for concentrations of cadmium, lead, and mercury in blood, urine, hair, and nails. The effect of gender and smoking on such levels was studied. The influence of dental amalgam on the levels of mercury in these biological samples was also examined. The results obtained show that only blood lead, which increased among males, was affected by gender. Blood levels of cadmium and lead as well as hair lead appeared to increase with smoking habit. Mercury levels in blood and urine were related to the presence of dental amalgam fillings. International comparisons between our results and the corresponding levels in other localities in the world showed that there were environmentally related variations in terms of cadmium levels in hair, lead levels in blood, urine, hair, and nails, and mercury levels in blood, hair, and nails. In conclusion, reference intervals of cadmium, lead, and mercury in the biological samples are environmentally related parameters. Some factors, such as gender, smoking habit, and the presence of dental amalgam fillings, may affect such levels and therefore should be considered.     

Genotypic differences in arsenic,mercury, lead and cadmium in milled rice (Oryza sativa L.)

The contents of arsenic, mercury, lead and cadmium in milled rice were determined. Among 216 genotypes, the As, Hg, Pb and Cd contents were ranged from 5.06 to 296.45, 2.46 to 65.85, 4.16 to 744.95 and 5.91 to 553.40 ng/g, respectively. Six genotypes with lower contents of toxic metal elements were selected. The averages of As and Pb contents for indica rice were higher than those of japonica rice, while the averages of Hg and Cd contents were in contrast. Compared with white brown rice, the milled rice from black and red brown rice contained lower contents of four elements. Significant negative correlation was found between As content and alkaline spread value. Significant correlations were observed between As and aspartic acid (Asp) content, Hg and Asp or leucine contents, Pb and cysteine or methionine contents. Cd content was significantly negatively correlated with protein and 14 amino acid contents.     

Cadmium, lead, and mercury in relation to reproductive hormones and anovulation in premenopausal women

Background: Metals can interfere with hormonal functioning by binding at the receptor site and through indirect mechanisms; thus, they may be associated with hormonal changes in premenopausal women.Objectives: We examined the associations between cadmium, lead, and mercury, and anovulation and patterns of reproductive hormones [estradiol, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone] among 252 premenopausal women 18–44 years of age who were enrolled in the BioCycle Study in Buffalo, New York.Methods: Women were followed for up to two menstrual cycles, with serum samples collected up to eight times per cycle. Metal concentrations were determined at baseline in whole blood by inductively coupled mass spectroscopy. Marginal structural models with stabilized inverse probability weights and nonlinear mixed models with harmonic terms were used to estimate the effects of cadmium, lead, and mercury on reproductive hormone levels during the menstrual cycle and anovulation.Results: Geometric mean (interquartile range) cadmium, lead, and mercury levels were 0.29 (0.19–0.43) μg/L, 0.93 (0.68–1.20) μg/dL, and 1.03 (0.58–2.10) μg/L, respectively. We observed decreases in mean FSH with increasing cadmium [second vs. first tertile: –10.0%; 95% confidence interval (CI), –17.3% to –2.5%; third vs. first tertile: –8.3%; 95% CI, –16.0% to 0.1%] and increases in mean progesterone with increasing lead level (second vs. first tertile: 7.5%; 95% CI, 0.1–15.4%; third vs. first tertile: 6.8%; 95% CI, –0.8% to 14.9%). Metals were not significantly associated with anovulation.Conclusions: Our findings support the hypothesis that environmentally relevant levels of metals are associated with modest changes in reproductive hormone levels in healthy, premenopausal women.     

Isomer profiles of perfluorochemicals in matched maternal, cord, and house dust samples: manufacturing sources and transplacental transfer

Background: Perfluorochemicals (PFCs) are detectable in the general population and in the human environment, including house dust. Sources are not well characterized, but isomer patterns should enable differentiation of historical and contemporary manufacturing sources. Isomer-specific maternal–fetal transfer of PFCs has not been examined despite known developmental toxicity of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in rodents.Objectives: We elucidated relative contributions of electrochemical (phased out in 2001) and telomer (contemporary) PFCs in dust and measured how transplacental transfer efficiency (TTE; based on a comparison of maternal and cord sera concentrations) is affected by perfluorinated chain length and isomer branching pattern.Methods: We analyzed matching samples of house dust (n = 18), maternal sera (n = 20), and umbilical cord sera (n = 20) by isomer-specific high-performance liquid chromatography tandem mass spectrometry.Results: PFOA isomer signatures revealed that telomer sources accounted for 0–95% of total PFOA in house dust (median, 31%). This may partly explain why serum PFOA concentrations are not declining in some countries despite the phase-out of electrochemical PFOA. TTE data indicate that total branched isomers crossed the placenta more efficiently than did linear isomers for both PFOS (p < 0.01) and PFOA (p = 0.02) and that placental transfer of branched isomers of PFOS increased as the branching point moved closer to the sulfonate (SO₃^–) end of the molecule.Conclusions: Results suggest that humans are exposed to telomer PFOA, but larger studies that also account for dietary sources should be conducted. The exposure profile of PFOS and PFOA isomers can differ between the mother and fetus—an important consideration for perinatal epidemiology studies of PFCs.     

Association of environmental exposure to heavy metals and eczema in US population: Analysis of blood cadmium,lead, and mercury

ABSTRACT

Objectives: We aim to explore the association between blood heavy metal concentrations of cadmium, lead, and mercury with ever-report of eczema in the US population.

Methods: We used NHANES cross-sectional data from 2005–2006. Eczema was measured among 4509 adults and 3898 non-adults. The association between eczema and tertiles of concentrations of cadmium, lead, mercury was estimated using multivariate logistic regression models adjusted for different confounding variables. The estimation was also stratified by gender.

Results: The prevalence of ever-report of eczema was 7.63% in adults and 13.42% in non-adults. None of the heavy metals was significantly associated with increased ORs of eczema after potential confounding variables were adjusted in the models. Our results remained null after stratifying for gender.

Conclusions: Blood cadmium, lead, and mercury were not associated with reports of eczema in general US population.     

泛素-蛋白酶体途径及其对镉的应答反应

泛素-蛋白酶体途径是真核细胞内一种高效蛋白降解途径。它参与接触镉后细胞抗镉毒性的应答反应，是去除镉接触诱导产生的异常蛋白和修复镉损伤的DNA的重要途径。但接触镉也可使细胞内的泛素蛋白发生积聚，从而影响细胞的存活。这些反应的具体机制还有待进一步深入研究。     

血管内皮生长因子及其受体与可溶性血管内皮生长因子受体-1对妊娠期糖尿病与围生儿结局的预测价值

目的探讨妊娠期糖尿病(GDM)孕妇血清中血管内皮生长因子(VEGF)及其受体(VEGFR)所介导的胎盘血管病变与围生儿结局间的关系,以及血清中可溶性血管内皮生长因子受体(sVEGFR)-1水平,对VEGF-VEGFR轴发挥的生物学效应。 方法选取2011年1月至12月在本中心被诊断为GDM、孕龄为24～28孕周的孕妇100例纳入GDM组;选择同期在相同医院常规产前检查、相同孕龄的50例正常孕妇,纳入对照组。采集两组孕妇血样,测量糖化指标：空腹血糖(FPG)值,糖化血红蛋白(HbA1c)与VEGF。GDM组经常规干预治疗后,再采集血样测定FPG值,HbA1c及VEGF,并与对照组进行统计学分析。分娩后,收集胎盘,分析胎盘组织中VEGFR蛋白表达。根据GDM组孕妇分娩后的围生儿结局,将其分别纳入GDM围生儿异常组(n＝34)与GDM围生儿正常组(n＝66)(本研究遵循的程序符合本院人体试验委员会所制定的伦理学标准,得到该委员会批准,分组征得受试对象本人的知情同意,并与之签署临床研究知情同意书)。 结果①GDM组孕妇血清VEGF水平、HbA1c及FPG值均明显高于对照组,差异有统计学意义(P<0.05)。②GDM组孕妇经干预治疗后,孕晚期FPG明显降低(P<0.05),HbA1c与对照组比较,差异无统计学意义(P>0.05),血清VEGF水平仍保持较高水平。③GDM组孕妇血清VEGF与sVEGFR-1水平呈负相关(r＝－0.497,P<0.01)。④与GDM组孕妇所分娩围生儿的血清VEGF水平显著高于对照组孕妇所分娩围生儿,且差异有统计学意义(P<0.05)。⑤采用多因素非条件logistic回归法对GDM组与对照组孕妇血清VEGF表达水平的分析结果显示,VEGF是GDM围生儿结局异常的危险因子(OR＝5.196, 95% CI: 1.845～14.610,P<0.001)。⑥采用Western印迹法测定胎盘组织中VEGFR蛋白表达量显示,GDM围生儿异常组较GDM围生儿正常组显著升高,差异有统计学意义(P<0.05)。 结论①GDM孕妇血清VEGF升高是其围生儿结局的一个不利因素,血清VEGF水平高可作为GDM不良围生儿结局的预测指标。②血循环中sVEGFR-1可通过竞争结合方式中和VEGF,抑制其下游信号传递。血清低sVEGFR-1水平可作为GDM病变中VEGF-VEGFR轴过度活跃的生物标记。     

Genetic Effects on Toxic and Essential Elements in Humans: Arsenic,Cadmium, Copper,Lead, Mercury,Selenium, and Zinc in Erythrocytes

Background and objectives

An excess of toxic trace elements or a deficiency of essential ones has been implicated in many common diseases or public health problems, but little is known about causes of variation between people living within similar environments. We estimated effects of personal and socioeconomic characteristics on concentrations of arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), selenium (Se), and zinc (Zn) in erythrocytes and tested for genetic effects using data from twin pairs.

Methods

We used blood samples from 2,926 adult twins living in Australia (1,925 women and 1,001 men; 30–92 years of age) and determined element concentrations in erythrocytes by inductively coupled plasma-mass spectrometry. We assessed associations between element concentrations and personal and socioeconomic characteristics, as well as the sources of genetic and environmental variation and covariation in element concentrations. We evaluated the chromosomal locations of genes affecting these characteristics by linkage analysis in 501 dizygotic twin pairs.

Results

Concentrations of Cu, Se, and Zn, and of As and Hg showed substantial correlations, concentrations of As and Hg due mainly to common genetic effects. Genetic linkage analysis showed significant linkage for Pb [chromosome 3, near SLC4A7 (solute carrier family 4, sodium bicarbonate cotransporter, member 7)] and suggestive linkage for Cd (chromosomes 2, 18, 20, and X), Hg (chromosome 5), Se (chromosomes 4 and 8), and Zn {chromosome 2, near SLC11A1 [solute carrier family 11 (proton-coupled divalent metal ion transporters)]}.

Conclusions

Although environmental exposure is a precondition for accumulation of toxic elements, individual characteristics and genetic factors are also important. Identification of the contributory genetic polymorphisms will improve our understanding of trace and toxic element uptake and distribution mechanisms.     

亚硝胺暴露剂量、时间与肺癌效应关系和致癌多阶段模型的探讨

目的分析该橡胶工人队列中亚硝胺暴露及与其有关的时间变量的肺癌危险度。方法应用Ｐｏｉｓｏｎ相乘模型和致癌多阶段理论。结果肺癌危险度随亚硝胺暴露年数增加而稳定升高,从暴露开始后经过一个潜隐期（大约２０～３０年）,肺癌危险度达到最高峰,然后迅速下降。结论本资料中亚硝胺暴露对肺癌危险度所显示的行为符合晚期阶段致癌原的特性     

Associations of toenail arsenic, cadmium, mercury, manganese, and lead with blood pressure in the normative aging study

Background: Arsenic, cadmium, mercury, and lead are associated with cardiovascular disease in epidemiologic research. These associations may be mediated by direct effects of the metals on blood pressure (BP) elevation. Manganese is associated with cardiovascular dysfunction and hypotension in occupational cohorts.Objectives: We hypothesized that chronic arsenic, cadmium, mercury, and lead exposures elevate BP and that manganese lowers BP.Methods: We conducted a cross-sectional analysis of associations between toenail metals and BP among older men from the Normative Aging Study (n = 639), using linear regression and adjusting for potential confounders.Results: An interquartile range increase in toenail arsenic was associated with higher systolic BP [0.93 mmHg; 95% confidence interval (CI): 0.25, 1.62] and pulse pressure (0.76 mmHg; 95% CI: 0.22, 1.30). Positive associations between arsenic and BP and negative associations between manganese and BP were strengthened in models adjusted for other toenail metals.Conclusions: Our findings suggest associations between BP and arsenic and manganese. This may be of public health importance because of prevalence of both metal exposure and cardiovascular disease. Results should be interpreted cautiously given potential limitations of toenails as biomarkers of metal exposure.