Organic and Inorganic Mercury in Biological Samples of Flouresecent Lamp Industries Workers and Health Risks

Objective The present study aims to investigate the concentrations of Hg and its aspects methyl mercury(Me-Hg) and inorganic mercury(I-Hg) in the biological samples(BSs) of fluorescent lamp industries workers(FLIWs).Methodology Different BSs including red blood cells(RBCs),plasma,urine,hair and nails were collected from the workers exposed to Hg and unexposed persons were selected as control group to measure both the T-Hg concentration as well as its species in different biological samples through quantitative analysis.Health data was collected through questionnaire survey.Results The mean concentrations of T-Hg(31.9 μg/L),Me-Hg(27.7 μg/L),and I-Hg(5.36 μg/L) in RBCs were found significantly(P 0.001) higher among the workers(n = 40) as compared to the control group(n = 40).Similarly the mean Hg concentrations in plasma,urine,hair and nails were also significantly higher among the workers than the control group.The statistical relation between Hg concentration and demographic characteristics observed that workers experience and fish consumption has increased the Hg concentration while age,weight and smoking found no significant effect on Hg concentration in the BSs.Conclusion The study observed that the workers were highly exposed to high concentration of Hg and they are at a high health risk.     

松花江汞污染治理后沿江渔民发汞调查

调查结果表明，沿江渔民发汞均值为２．２５μｇ／ｇ，与对照点相比差异显著（Ｐ＜０．０１），其中扶余一松江段渔民发汞均值２．５４μｇ／ｇ，高于其他各江段；３０～４０岁年龄组渔民发汞值超过正常值者占４５％，比其他各年龄组多；在调查的１１９５人中有２５名发汞值超过１０μｇ／ｇ，其中１８人发甲基汞含量超过５μｇ／ｇ。     

无机汞对男工内分泌和大鼠睾丸微量元素的影响

应用放射免疫分析法（ＲＩＡ）和流行病学调查，对４０名接触汞和４０名非接触汞男工进行了血清甲状腺激素、性激素水平和生殖功能的测定。结果表明，接触组男工的阳萎、早泄、性欲减退发生率和男工妻子的早产、自然流产发生率以及血清甲状腺激素（ＦＴ３和ＦＴ４）含量明显增多，每周性交次数和血清睾酮含量显著减少。上述各项与对照组比较差异非常显著。应用火焰光度法，对氯化汞染毒后大鼠睾丸组织的微量元素进行测定，实验组的锌值明显降低。结果提示氯化汞能够影响甲状腺激素、睾酮和锌元素水平。     

实验性汞中毒时肾组织和尿中碱性磷酸酶活性的变化

本研究采用亚急性汞中毒肾损害的大鼠模型,探讨了汞中毒时血、肾和尿中碱性磷酸酶(ALP)活性的变化关系。结果表明,大鼠肾匀浆中 ALP活性明显低于对照组,尿 ALP活性则显著增加。ALP 活性降低的部位在肾近曲小管。体外实验未发现氯化汞对肾、尿ALP 具有直接抑制作用或激活作用。尿中ALP 活性的增高是汞引起的肾小管上皮细胞损伤所致。它可作为汞中毒肾损害的一个观察指标。     

Dietary selenium's protective effects against methylmercury toxicity

Dietary selenium (Se) status is inversely related to vulnerability to methylmercury (MeHg) toxicity. Mercury exposures that are uniformly neurotoxic and lethal among animals fed low dietary Se are far less serious among those with normal Se intakes and are without observable consequences in those fed Se-enriched diets. Although these effects have been known since 1967, they have only lately become well understood. Recent studies have shown that Se-enriched diets not only prevent MeHg toxicity, but can also rapidly reverse some of its most severe symptoms. It is now understood that MeHg is a highly specific, irreversible inhibitor of Se-dependent enzymes (selenoenzymes). Selenoenzymes are required to prevent and reverse oxidative damage throughout the body, particularly in the brain and neuroendocrine tissues. Inhibition of selenoenzyme activities in these vulnerable tissues appears to be the proximal cause of the pathological effects known to accompany MeHg toxicity. Because Hg's binding affinities for Se are up to a million times higher than for sulfur, its second-best binding partner, MeHg inexorably sequesters Se, directly impairing selenoenzyme activities and their synthesis. This may explain why studies of maternal populations exposed to foods that contain Hg in molar excess of Se, such as shark or pilot whale meats, have found adverse child outcomes, but studies of populations exposed to MeHg by eating Se-rich ocean fish observe improved child IQs instead of harm. However, since the Se contents of freshwater fish are dependent on local soil Se status, fish with high MeHg from regions with poor Se availability may be cause for concern. Further studies of these relationships are needed to assist regulatory agencies in protecting and improving child health.     

低剂量甲基汞在小鼠体内分布及其对细胞周期进程的影响

连续９０天饮用含甲基汞浓度为１／１０００ＬＤ５０、１／１００ＬＤ５０、１／５０ＬＤ５０和１／１０ＬＤ５０的自来水的雄性昆明小鼠，各脏器中总汞含量均高于对照组（Ｐ＜０．０５～０．００５），并且随着染毒剂量增加，脏器中总汞含量也随之增高。同时采用ＦＡＣＳｃａｎ流式细胞仪和“ＣｅｌｌＦＩＴ”软件分析脾细胞周期进程，发现除１／１０００ＬＤ５０剂量组外，其余各剂量组从Ｇｏ／Ｇ１时相进入Ｓ时相的脾细胞百分数均明显高于对照组（Ｐ＜０．０５），与染毒剂量呈明显正相关。表明连续经口摄入低剂量甲基汞小鼠脾细胞周期进程加快，细胞ＤＮＡ复制增强。     

Mercury from gold minings in the Pantanal of Pocone (Mato Grosso,Brazil)

The Pocone gold minings are situated in the Bento Gomes River Basin, at the border of the Pantanal of Mato Grosso. Gold-bearing quartz veins are removed from the subsoils, milled with water, centrifuged and the heavier fraction is subsequently mixed with mercury for gold separation. The gold mining activities caused a very intensive landscape change, threatening many environmental processes like sediment control and storage and recycling capacity of mercury. Cold Vapor Atomic Fluorescence System (CVAFS) was used to determinate total mercury in water, suspended material and sediments from Bento Gomes River, sampled monthly for 1 year. Apart from the fact that mercury concentrations are low in water and bottom sediments, they are slightly higher in relation to background levels measured in the area. The concentration in suspended material is also lower than other rivers with gold mining activities, but the floodplains of the Bento Gomes River act as mercury sinks. Therefore, the discharge of mercury into the Pantanal floodplain should be avoided, in spite of actual contamination of the system being very low.     

Placental transfer and fetal distribution of cadmium and mercury after treatment with dithiocarbamates

The distribution in pregnant C57BL mice (day 18 of gestation) of intravenously administered cadmium (Cd) chloride and mercury (Hg) chloride (0.75 mol/kg b.w.) was studied, with or without previous dithiocarbamate pretreatment. Diethyldithiocarbamate (DEDTC), disulfiram, or thiram (2×1 mmol/kg b.w.) or vehicle (gelatine) alone, were given by gavage 2 h before and immediately after injection of the metals. The mice were sacrificed 4 and 24 h later and subjected to autoradiography or impulse counting of excised organs.All the dithiocarbamates increased the concentration of both Cd and Hg in brain and most other maternal organs. While DEDTC and thiram, in that order, strongly increased Cd concentrations in whole fetuses (around 17-fold at 4 h) and all fetal organs measured, disulfiram caused a decrease in fetal Cd concentrations. For Hg, all the dithiocarbamates substantially decreased fetal levels. Disulfiram, for example, decreased Hg levels by a factor of 5. The 24 h values confirmed those at 4 h both elements, although the differences between control and treatment groups were less pronounced.Although the results suggest the formation of lipid-soluble metal-dithiocarbamate complexes in vivo (e.g., increased concentration in brain), this does not necessarily lead to increased fetal levels of the metals. The increased levels of Cd after thiram and DEDTC pretreatment, however, indicate a risk for higher Cd fetotoxicity. It is likely that Cd is released in fetal cells following metabolism of the dithiocarbamate moiety of the complex.     

刺梨利康饮对慢性汞中毒脂质过氧化损害的拮抗作用

用８３７－４９μｍｏｌ／Ｌ 含汞水饲养大鼠８ 周,复制出慢性汞中毒模型,然后分别自由饮用含维生素Ｃ６８１２－７６μｍｏｌ／Ｌ 的利康饮和ｉｐ １２５ｍｇ／ｋｇ 二巯基丙磺酸钠（ＤＭＰＳ）３ 周,探讨利康饮和ＤＭＰＳ 对慢性汞中毒大鼠尿汞排泄和脂质过氧化损害的影响。结果发现,慢性汞中毒引起血清、肝、脑和肾还原型谷胱甘肽（ＧＳＨ） 含量显著降低,血清、肝、脑和肾丙二醛（ ＭＤＡ） 含量、尿蛋白含量及尿碱性磷酸酶（ＡＫＰ） 活性显著升高;利康饮可显著增加尿汞排泄和血清维生素Ｃ 含量,并使慢性汞中毒引起的血清、肝、脑和肾ＧＳＨ 含量显著回升,血清、脑和肾ＭＤＡ 含量、尿蛋白含量及尿ＡＫＰ 活性显著回降;ＤＭＰＳ 虽有明显促进尿汞排泄效果和使血清ＭＤＡ 含量显著回降的作用,但对慢性汞中毒引起的其它脂质过氧化损害指标影响不明显。结果表明,刺梨利康饮具有一定排汞效果,并对慢性汞中毒引起的机体抗氧化功能降低和脂质过氧化损害具有明显拮抗作用。     

Interleukin-1 receptor antagonist in newborn babies and pregnant women

We have used patch-clamp techniques to study the effect of the sulfhydryl group oxidizing agents mercury and thimerosal on calcium-activated nonselective cation channels from brown adipose tissue. 100 nmol/l mercury and 50 mol/l thimerosal induced a complete block. Blockade could be reversed by reduction of the mercaptide by dithiotreitol (DTT). Mercury was found to be the most potent blocker (IC₅₀-value 21×10^–9 mol/l), whereas thimerosal (IC₅₀-value 1.5×10^–6 mol/l) was as effective as 3,5-dichlorodiphenylamine-2-carboxylic acid (DCDPC). The DCDPC effect, however, could not be reversed by DTT, indicating different blocking mechanisms. It is concluded that SH-groups are involved in gating of the calcium-activated nonselective channel.