The concentrations of total mercury and methylmercury in sediments were determined at the dam of the Wujiangdu Reservoir in different seasons. Total mercury (HgT) levels in the whole sediment profile were 254.2±4...The concentrations of total mercury and methylmercury in sediments were determined at the dam of the Wujiangdu Reservoir in different seasons. Total mercury (HgT) levels in the whole sediment profile were 254.2±47.0 ng/g in winter, 254.2±31.6 ng/g in spring, and 256.7±60.8 ng/g in summer, without significant variations in different seasons or at different depths. In contrast, the methylmercury (MeHg) compounds were most abundant at the sediment-water interface and decreased progressively with depth. MeHg contents of the sediments during different seasons are highly dependent on microbial activity, and seem to be higher when Hg (II)-methylating microorganisms are active. Thus, MeHg levels tend to rise in the loci where nutrient supplies and biological productivity are favorable. The percentage of HgT that is present as MeHg in the sediments increased gradually from December 2003 to April 2004 and to July 2004.展开更多
Twice a year continuous samples of Rana Chensinensis and sediments have been collected near gold mine in the upstream region of Songhua River from 2000 to 2002, for analyzing the total mercury (THg), methylmercury (Me...Twice a year continuous samples of Rana Chensinensis and sediments have been collected near gold mine in the upstream region of Songhua River from 2000 to 2002, for analyzing the total mercury (THg), methylmercury (MeHg) concentration and correlation in sediments, muscles, livers of the frog. The study indicates that THg and MeHgconcentrations in polluted samples near the gold mine are higher than those in unpolluted ones. THg and MeHg con-centrations are higher in autumn, in female, and in livers than those in spring, in male, in muscles respectively. The order of concentration degree in the frog organizations is as follows: liver>muscle>ovum>Fallopian tube. MeHg is themain form of mercury (Hg) existing in autumn, while inor-ganic Hg is in spring. There is no distinct difference ofCMeHg/CTHg between male and female, livers and muscles. The correlation between MeHg concentrations in the river sedi-ments and in the frog’s livers and muscles are significant, which is related to disorderly discharge of Hg.展开更多
Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion(Hg^(2+)) and organic methylmercu...Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion(Hg^(2+)) and organic methylmercury(CH_3Hg^+). Detection of the two mercury ions is a particularly active topic in the molecular sensing field during the past decade. However, efficient sensors that can sensitively detect and discriminate the two species are rare. In this work, we adopt the concept of restriction of intramolecular rotations which is the basis of aggregation induced emission, and design a molecular probe with pyridyl group as the chelating unit and 1,8-naphthalimide as the fluorescent unit for the detection of both Hg^(2+) and CH_3Hg^+. When the probe is free in solution, it exhibits weak fluorescence because free intramolecular rotations of the 1,8-naphthalimide moieties non-radiatively annihilate its excited state. However, upon coordination with Hg^(2+) or CH_3Hg^+, the rotation of 1,8-naphthalimide moieties would be restricted due to the chelation between 1,8-naphthalimide and Hg^(2+) or CH_3Hg^+, leading to significantly enhanced fluorescent emission. The response induced by Hg^(2+) is much stronger than CH_3Hg^+; but for specific detection of CH_3Hg^+, we introduced a T-rich DNA fragment which could completely mask Hg^(2+) in solution. Furthermore, we have employed the sensor for confocal imaging of Hg^(2+)and CH_3Hg^+in immobilized cells. We expect the probe design tactics can be generally useful for sensing many other analytes.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.40532014).
文摘The concentrations of total mercury and methylmercury in sediments were determined at the dam of the Wujiangdu Reservoir in different seasons. Total mercury (HgT) levels in the whole sediment profile were 254.2±47.0 ng/g in winter, 254.2±31.6 ng/g in spring, and 256.7±60.8 ng/g in summer, without significant variations in different seasons or at different depths. In contrast, the methylmercury (MeHg) compounds were most abundant at the sediment-water interface and decreased progressively with depth. MeHg contents of the sediments during different seasons are highly dependent on microbial activity, and seem to be higher when Hg (II)-methylating microorganisms are active. Thus, MeHg levels tend to rise in the loci where nutrient supplies and biological productivity are favorable. The percentage of HgT that is present as MeHg in the sediments increased gradually from December 2003 to April 2004 and to July 2004.
基金This work was supported in part by the Key Project of the Ninth Five—year Resource and Ecological Environ—ment，CAS(Grant No．KZ952一S1-201) the National Natural Science Foundation of China(Grant No．30370262)．
文摘Twice a year continuous samples of Rana Chensinensis and sediments have been collected near gold mine in the upstream region of Songhua River from 2000 to 2002, for analyzing the total mercury (THg), methylmercury (MeHg) concentration and correlation in sediments, muscles, livers of the frog. The study indicates that THg and MeHgconcentrations in polluted samples near the gold mine are higher than those in unpolluted ones. THg and MeHg con-centrations are higher in autumn, in female, and in livers than those in spring, in male, in muscles respectively. The order of concentration degree in the frog organizations is as follows: liver>muscle>ovum>Fallopian tube. MeHg is themain form of mercury (Hg) existing in autumn, while inor-ganic Hg is in spring. There is no distinct difference ofCMeHg/CTHg between male and female, livers and muscles. The correlation between MeHg concentrations in the river sedi-ments and in the frog’s livers and muscles are significant, which is related to disorderly discharge of Hg.
基金funded by the National Basic Research Program of China(2013CB932800)the National Natural Science Foundation of China(21375130,31571010,21204089 and 21475132)
文摘Mercury is one of the major toxic pollutants and has many adverse effects on human health. The main mercury species in the environment or in living organisms are inorganic mercuric ion(Hg^(2+)) and organic methylmercury(CH_3Hg^+). Detection of the two mercury ions is a particularly active topic in the molecular sensing field during the past decade. However, efficient sensors that can sensitively detect and discriminate the two species are rare. In this work, we adopt the concept of restriction of intramolecular rotations which is the basis of aggregation induced emission, and design a molecular probe with pyridyl group as the chelating unit and 1,8-naphthalimide as the fluorescent unit for the detection of both Hg^(2+) and CH_3Hg^+. When the probe is free in solution, it exhibits weak fluorescence because free intramolecular rotations of the 1,8-naphthalimide moieties non-radiatively annihilate its excited state. However, upon coordination with Hg^(2+) or CH_3Hg^+, the rotation of 1,8-naphthalimide moieties would be restricted due to the chelation between 1,8-naphthalimide and Hg^(2+) or CH_3Hg^+, leading to significantly enhanced fluorescent emission. The response induced by Hg^(2+) is much stronger than CH_3Hg^+; but for specific detection of CH_3Hg^+, we introduced a T-rich DNA fragment which could completely mask Hg^(2+) in solution. Furthermore, we have employed the sensor for confocal imaging of Hg^(2+)and CH_3Hg^+in immobilized cells. We expect the probe design tactics can be generally useful for sensing many other analytes.
