Copper complexation by tannic acid in aqueous solution

The speciation of titrated copper in a dissolved tannic acid (TA) solution with an initial concentration of 4 mmol organic carbon (OC)/l was investigated in a nine-step titration experiment (Cu/OC molar ratio = 0.0030–0.0567). We differentiated between soluble and insoluble Cu species by 0.45 μm filtration. Measurements with a copper ion selective electrode (ISE) and diffusive gradients in thin films (DGT) were conducted to quantify unbound Cu(II) cations (‘free’ Cu) and labile soluble Cu complexes. For the DGT measurements, we used an APA hydrogel and a Chelex 100 chelating resin (Na form). Insoluble organic Cu complexes (>0.45 μm) was the dominant Cu species for Cu/OC = 0.0030–0.0567 with a maximum fraction of 0.96 of total Cu. At Cu/OC > 0.0100, Cu-catalysed degradation of aggregate structures resulted in a strong increase of free Cu and (labile) soluble Cu complexes with a maximum fraction of 0.28 and 0.32 of total Cu, respectively. Labile (i.e. DGT-detectable) soluble Cu complexes had a relatively high averaged diffusion coefficient (D) in the APA hydrogel (3.50 × 10⁻⁶– 5.58 × 10⁻⁶ cm² s⁻¹).     

鱼体甲基汞的萃取富集和测定

研究了苯萃取和半胱氨酸滤纸富集再用苯洗脱的方法,使鱼肉中甲基汞得到富集和提取。建立了气相色谱测定甲基汞的方法并对所建立的方法进行评价。结果表明:加标回收率为87.10%～105.69%;变异系数为2.93%。符合要求,大量样品实验表明,该方法适用于痕量甲基汞的提取和分析。     

Mesoscale variability related to iron speciation in a coastal Ross Sea area (Antarctica) during summer 2014

Dissolved iron (Fe) distribution and speciation was determined in water samples (0–200?m) collected in a coastal area near Terra Nova Bay during the austral summer of 2014. Nutrients, dissolved oxygen, chlorophyll-a, phytoplankton composition and prokaryotic biomass distribution were investigated in combination with measurements of the physical properties of the water columns and its dynamics. The dFe value was above the limiting growth concentration, ranging from 0.52 to 4.51?nM, and it showed a spatial variability with a horizontal length scale of about 10?km, according to the variability of the water column physical properties and to iron sources. The organic ligands (L) maintained the concentrations of dFe at levels much higher than the inorganic solubility of Fe, keeping it available for phytoplankton and the log K’_FeL values found (from 22.1 to 23.6) highlighted the presence of complexes of differing stabilities.     

Effects of mercury graded doses on redox status,metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali

Mercury (Hg) is a ubiquitous and a major environmental metal pollutant in the aquatic ecosystem. The present study was performed to evaluate the effect of mercury graded doses exposure on oxidative stress, redox status, metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali. Specimens were exposed for 96?h to three concentrations of Hg (40, 80 and 160?µg/L). Exposure of H. forskali to Hg promoted oxidative stress with an increase in malondialdehyde (MDA), protein carbonyl (PCO) and advanced oxidation protein products (AOPP) levels. An increase of glutathione (GSH), vitamin C (ViteC) and non-protein thiols (NPSH) contents was also observed. Additionally, antioxidant activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) increased especially with the highest doses of Hg indicating a great defense of the antioxidant system. Our investigation revealed an increase in total Metallothionein (MT) content which was more pronounced at the sharpest concentrations of Hg. A significant decline of AChE activity was also observed. In the intestine of Hg-treated H. forskali genotoxicity was confirmed by DNA degradation.     

两种螯合剂对汞在土壤-植物系统中迁移的影响

盆栽试验表明,螯合剂种类、浓度、施用时间等对莴笋产量的影响程度分别为５７．７２%、１６、０６%、２６．２２%,对汞在莴笋中的积累影响程度分别为４９．１５%、２．４７%、４８．３８%。在莴笋移栽时,施用０．１０ ｍｏｌ/Ｌ的ＤＴＰＡ,既可削减蔬菜中汞含量,又可促进蔬菜产量的增加。模拟试验表明,不同螯合剂只是对淋洗速度产生影响,而对滤液汞、土壤残留汞的影响不明显     

Seasonal variation of total dissolved arsenic and arsenic speciation in a polluted surface waterway

Seasonal differences in the dissolved arsenic concentration and speciation in a contaminated urban waterway in northwest England have been determined using a coupled ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS) technique. Waters sampled in the vicinity of an industrial works during relatively dry conditions in April 2000 were found to contain total arsenic concentrations (As) of up to 132 g L^–1, more than an order magnitude greater than the 4 g L^–1 maximum found in December 2000. The difference in As between the April and December sampling periods is speculated to be largely due to the irregular anthropogenic supply of arsenic to the watercourse. For both sampling periods, the dissolved arsenic was exclusively inorganic in nature and had an As(V)/As ratio of between 0.6 and 0.8. Analysis of samples taken downstream of the industrial site, after the confluence with a relatively As-poor stream, revealed that As(III), As(V) and As concentrations were lower than would be expected from conservative mixing. The As(V)/As ratio was also observed to decrease markedly. The loss of arsenic from solution is thought to be due to adsorption on the iron oxyhydroxide-rich sediment observed to coat the riverbed downstream of the confluence. The reduction in the As(V)/As ratio is believed to be due to the more rapid adsorption of As(V) compared to that of As(III). Deviations from conservative behaviour were more marked during the relatively dry April 2000 sampling period and suggest the increased importance of adsorption processes controlling arsenic availability during this time.     

汞矿地区人发中甲基汞的气相色谱测定

本文采用气相色谱法测定人发中甲基汞，对人发的酸度，浸取时间，人发与酸液的比例，以及无机汞存在的影响作了测定和选择，方法的平均回收率９６．６％，精确度２．８％，方法可靠性用氢化物原子荧光法核对，结果一致，并对我国某矿区职工，儿童及产妇发样分析结果作了讨论。     

废铁屑修复汞污染土壤的实验研究

应用工厂废弃物—铁屑做原料,探讨不同铁屑投加量对修复不同土壤类型、不同程度汞污染土壤的能力,并与修复水体汞污染作了对比;另外,首次将淋滤法与国际上新兴的土壤、地下水修复技术-PRB技术结合,研究其修复土壤汞污染的效果。结果表明,废铁屑可很快去除水体中的汞,去除率可达93%;在铁屑存在下,能一定程度预防和修复土壤汞污染,在相同水体汞污染程度条件下,时间是影响土壤汞污染程度的主要因素;在CaCl2淋洗液作用下的模拟PRB实验中,土壤有效汞含量降低,同时淋洗液中汞质量浓度低于1μg·L-1。因此,用废铁屑能有效预防和修复土壤汞污染,且将淋滤法与PRB技术联用,与将铁屑直接撒入土壤中相比效果好得多,且不会引起后续的水体二次污染,是一种很有应用潜力、值得深入研究的土壤修复方法。     

An Operationally Defined Method to Determine the Speciation of Mercury

This paper presents a modified method of an operationally determined speciation of mercury in soil. The analytical work was mainly concerned to suit properly with inductively coupled plasma-atomic emission spectrometry (ICP-AES). Soil samples analysed in this study were selected from open areas around a crematorium, a waste incinerator, and two power plants. Results show that both topsoil and subsoil samples were dominated by elemental mercury Hg(0) and mercuric sulphide (HgS). The significant correlation between sulphur concentration and HgS was found in topsoil samples.     

垃圾填埋场及周边水系中汞污染调查

对上海老港垃圾填埋场渗滤液、地下水和地表径流水监测分析表明：渗滤液中的汞主要为以颗粒态汞(S-Hg)形式存在，污水处理系统可以使颗粒态汞(S-Hg)随颗粒物沉积到底泥中，但是对可溶态汞(D-Hg)去除没有明显作用；芦苇湿地可以有效地吸附和吸收渗滤液中各种形态汞，使汞浓度降到一个较低的水平；对地下水和地表水的分析结果显示，地下水基本没有受到汞污染，而地表水受到一定程度的污染。