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Divalent Mercury in Dissolved Organic Matter Is Bioavailable to Fish and Accumulates as Dithiolate and Tetrathiolate Complexes
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2019-02-05 , DOI: 10.1021/acs.est.8b06579 Jean-Paul Bourdineaud 1 , Maria Gonzalez-Rey 2 , Mauro Rovezzi 3 , Pieter Glatzel 3 , Kathryn L. Nagy 4 , Alain Manceau 5
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2019-02-05 , DOI: 10.1021/acs.est.8b06579 Jean-Paul Bourdineaud 1 , Maria Gonzalez-Rey 2 , Mauro Rovezzi 3 , Pieter Glatzel 3 , Kathryn L. Nagy 4 , Alain Manceau 5
Affiliation
The freshwater cyprinid Tanichthys albonubes was used to assess the bioavailability of divalent mercury (Hg(II)) complexed in dissolved organic matter (DOM) to fish. The fish acquired 0.3 to 2.2 μg Hg/g dry weight after 8 weeks in aquaria containing DOM from a Carex peat with complexed mercury at initial concentrations of 14 nM to 724 nM. Changes in the relative proportions of dithiolate Hg(SR)2 and nanoparticulate β-HgS in the DOM, as quantified by high energy-resolution XANES (HR-XANES) spectroscopy, indicate that Hg(SR)2 complexes either produced by microbially induced dissolution of nanoparticulate β-HgS in the DOM or present in the original DOM were the forms of mercury that entered the fish. In the fish with 2.2 μg Hg/g, 84 ± 8% of Hg(II) was bonded to two axial thiolate ligands and one or two equatorial N/O electron donors (Hg[(SR)2+(N/O)1–2] coordination), and 16% had a Hg(SR)4 coordination, as determined by HR-XANES. For comparison, fish exposed to Hg2+ from 40 nM HgCl2 contained 10.4 μg Hg/g in the forms of dithiolate (20 ± 10%) and tetrathiolate (23 ± 10%) complexes, and also HgxSy clusters (57 ± 15%) having a β-HgS-type local structure and a dimension that exceeded the size of metallothionein clusters. There was no evidence of methylmercury in the fish or DOM within the 10% uncertainty of the HR-XANES. Together, the results indicate that inorganic Hg(II) bound to DOM is a source of mercury to biota with dithiolate Hg(SR)2 complexes as the immediate species bioavailable to fish, and that these complexes transform in response to cellular processes.
中文翻译:
溶解的有机物中的二价汞可被鱼类生物利用,并以二硫醇盐和四硫醇盐复合物形式积累
淡水鲤类鱼类Tanichthys albonubes用于评估溶解于有机物(DOM)中的二价汞(Hg(II))对鱼类的生物利用度。该鱼在含有DOM的Carex泥炭中含DOM的水族箱中培养8周后,其干重为0.3至2.2μgHg / g ,初始浓度为14 nM至724 nM。通过高能分辨XANES(HR-XANES)光谱法定量,二硫代Hg(SR)2和纳米颗粒β-HgS在DOM中的相对比例变化表明Hg(SR)2微生物诱导的纳米颗粒β-HgS在DOM中的溶解产生的复合物,或存在于原始DOM中的复合物,都是进入鱼类的汞形式。在具有2.2μgHg / g的鱼中,84±8%的Hg(II)与两个轴向硫醇盐配体和一个或两个赤道N / O电子供体(Hg [(SR)2 +(N / O)1 –2 ]协调),根据HR-XANES确定,有16%的Hg(SR)4协调。为了进行比较,从40 nM HgCl 2中暴露于Hg 2+的鱼以二硫醇盐(20±10%)和四硫醇盐(23±10%)络合物的形式含有10.4μgHg / g,还含有Hg x S yβ-HgS型局部结构的簇(57±15%),其尺寸超过了金属硫蛋白簇的大小。在HR-XANES的10%不确定性范围内,没有鱼类或DOM中甲基汞的证据。总之,结果表明,与DOM结合的无机Hg(II)是具有二硫代Hg(SR)2复合物作为生物可直接用于鱼类的生物群中汞的来源,并且这些复合物响应细胞过程而发生转化。
更新日期:2019-02-06
中文翻译:
溶解的有机物中的二价汞可被鱼类生物利用,并以二硫醇盐和四硫醇盐复合物形式积累
淡水鲤类鱼类Tanichthys albonubes用于评估溶解于有机物(DOM)中的二价汞(Hg(II))对鱼类的生物利用度。该鱼在含有DOM的Carex泥炭中含DOM的水族箱中培养8周后,其干重为0.3至2.2μgHg / g ,初始浓度为14 nM至724 nM。通过高能分辨XANES(HR-XANES)光谱法定量,二硫代Hg(SR)2和纳米颗粒β-HgS在DOM中的相对比例变化表明Hg(SR)2微生物诱导的纳米颗粒β-HgS在DOM中的溶解产生的复合物,或存在于原始DOM中的复合物,都是进入鱼类的汞形式。在具有2.2μgHg / g的鱼中,84±8%的Hg(II)与两个轴向硫醇盐配体和一个或两个赤道N / O电子供体(Hg [(SR)2 +(N / O)1 –2 ]协调),根据HR-XANES确定,有16%的Hg(SR)4协调。为了进行比较,从40 nM HgCl 2中暴露于Hg 2+的鱼以二硫醇盐(20±10%)和四硫醇盐(23±10%)络合物的形式含有10.4μgHg / g,还含有Hg x S yβ-HgS型局部结构的簇(57±15%),其尺寸超过了金属硫蛋白簇的大小。在HR-XANES的10%不确定性范围内,没有鱼类或DOM中甲基汞的证据。总之,结果表明,与DOM结合的无机Hg(II)是具有二硫代Hg(SR)2复合物作为生物可直接用于鱼类的生物群中汞的来源,并且这些复合物响应细胞过程而发生转化。