Metal concentrations and mobility in marine sediment and groundwater in coastal reclamation areas: a case study in Shenzhen, China

The concentrations of metals in the buried marine sediment and groundwater were differently affected by land reclamation. Nine metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in sediment and coastal groundwater from reclamation areas in Shenzhen were examined. The gradually decreased concentrations (V, Cr, Mn, Ni, Cu, Zn) in sediment and relatively higher concentrations (V, Cr, Mn, Co, Ni, Cu and Cd) in groundwater within reclamation areas were observed. The increase of V, Cr, Mn, Ni, Cu and Cd concentrations in groundwater within reclamation areas subsequently after land reclamation should be resulted from the mobilization of these metals accumulated in the sediment. These metals appear to be easily mobilized from solid phase to solution phase after reclamation. The physico-chemical changes such as reduction in pH and salinity in water environment induced by land reclamation appear to be responsible for metal mobility in the sediment-groundwater system.     

Alterations to proteome and tissue recovery responses in fish liver caused by a short-term combination treatment with cadmium and benzo[a]pyrene

The livers of soles (Solea senegalensis) injected with subacute doses of cadmium (Cd), benzo[a]pyrene (B[a]P), or their combination, were screened for alterations to cytosolic protein expression patterns, complemented by cytological and histological analyses. Cadmium and B[a]P, but not combined, induced hepatocyte apoptosis and Kupfer cell hyperplasia. Proteomics, however, suggested that apoptosis was triggered through distinct pathways. Cadmium and B[a]P caused upregulation of different anti-oxidative enzymes (peroxiredoxin and glutathione peroxidase, respectively) although co-exposure impaired induction. Similarly, apoptosis was inhibited by co-exposure, to which may have contributed a synergistic upregulation of tissue metalloproteinase inhibitor, β-actin and a lipid transport protein. The regulation factors of nine out of eleven identified proteins of different types revealed antagonistic or synergistic effects between Cd and B[a]P at the prospected doses after 24 h of exposure. The results indicate that co-exposure to Cd and B[a]P may enhance toxicity by impairing specific responses and not through cumulative damage.     

Multivariate statistics to investigate metal contamination in surface soil

The modification of soil composition in the urbanized area of Ankara due to wet-dry deposition and pollution-derived particles from the atmosphere is investigated by analyzing 120 surface soil samples, collected from the urbanized area and its un-urbanized surrounding, for major, minor and trace elements. Concentrations of elements from human activity (e.g. Cd, Pb, Cr, Zn, Cu and Ca) in the urbanized area were higher than their corresponding concentrations in global average soil and soil in un-urbanized areas outside the urbanized area. Metal contents in soil were very high in densely populated districts and around some industrial facilities. The only exception was Pb distribution, which was more dispersed, due to the nature of motor vehicle emissions. Alteration of the Cd, Zn, Cu and Cr content of soil was confined to the inhabited and industrial areas, whereas enrichment factors of these elements were close to unity in the remaining study area. Factor analysis identified two polluted soil factor associations. One factor includes elements, such as Zn and Cd, which had high factor scores in inhabited areas and the other factor (high loading of Pb) represents soil polluted by motor vehicle emissions.     

Environmental regulatory failure and metal contamination at the Giap Lai pyrite mine, Northern Vietnam

The causes for the failure in enforcement of environmental regulations at the Giap Lai pyrite mine in northern Vietnam are considered and the environmental impacts that are associated with this mine are evaluated. It is shown that sulphide-rich tailings and waste rock in the mining area represent significant sources of acid rock drainage (ARD). The ARD is causing elevated metal levels in downstream water bodies, which in turn, represent a threat to both human health and to aquatic ecosystems. Metal concentrations in impacted surface waters have increased after mine closure, suggesting that impacts are becoming progressively more serious. No post-closure, remediation measures have been applied at the mine, in spite of the existence of environmental legislation and both central and regional institutions charged with environmental supervision and control. The research presented here provides further emphasis for the recommendation that, while government institutions may need to be strengthened, and environmental regulations need to be in place, true on the ground improvement in environmental quality in Vietnam and in many other developing countries require an increased focus on promoting public awareness of industrial environmental issues.     

Effects of organic ligands on fractionation of rare earth elements (REEs) in hydroponic plants: an application to the determination of binding capacities by humic acid for modeling

Previous studies have revealed the fractionation processes of rare earth elements (REEs) in hydroponic plants, with a heavy REE (HREE, the elements from Gd to Lu) enrichment in leaves. In this study, effects on the HREE enrichment in soybean leaves with additions of carboxylic acids (acetate, malate, citrate, NTA, EDTA and DTPA) and two soil humic acids (HAs) were investigated. REE speciation in carboxylic acid and HA solutions was simulated using Visual MINTEQ and Model V, respectively. The results showed that the effects caused by carboxylic acids were strongly dependent on the differences between their binding strengths for light REEs (LREEs, the elements from La to Eu) and those for HREEs. A good correlation existed between these effects and the changes of free REE ions in solutions. This relationship was also observed for the HA treatments, provided that the intrinsic equilibrium constants of REEs for cation–proton exchange with HA (i.e., pK_MHA) in Model V were estimated using a free-energy relationship with the stability constants for REE complexation with lactic acid. It is suggested that this set of pK_MHA values is more suitable for use in Model V for the simulation of REE complexation with HA.     

Ni adsorption and Ni-Al LDH precipitation in a sandy aquifer: an experimental and mechanistic modeling study

Mining activities and industries have created nickel (Ni) contaminations in many parts of the world. The objective of this study is to increase our understanding of Ni adsorption and Nickel-Aluminium Layered Double Hydroxide (Ni-Al LDH) precipitation to reduce Ni mobility in a sandy soil aquifer. At pH ≥7.2 both adsorption and Ni-Al LDH precipitation occurred. In batch experiments with the sandy soil up to 70% of oxalate-extractable Al was taken up in LDH formation during 56 days. In a long term column experiment 99% of influent Ni was retained at pH 7.5 due to Ni adsorption (≈34%) and Ni-Al LDH precipitation (≈66%) based on mechanistic reactive transport modeling. The subsequent leaching at pH 6.5 could be largely attributed to desorption. Our results show that even in sandy aquifers with relatively low Al content, Ni-Al LDH precipitation is a promising mechanism to immobilize Ni.     

金属矿山废弃地生态修复技术研究

总结了金属矿山废弃地的类型、特征,简述了其对环境的影响和后果。对金属矿山废弃地的生态修复技术进行了归纳和分类,在此基础上分析了基质改良技术、植物修复技术、微生物修复技术、各类技术在矿山废弃地生态修复实践中的适用性和优缺点,并指出植物修复技术是应用前景最好的技术。最后,对金属矿山废弃地生态修复技术的发展方向进行了讨论。     

无机盐对城市污泥堆肥处理中重金属Pb和Zn的形态影响研究

以沈北新区虎台镇污水处理厂剩余活性污泥作为研究对象,采用Tessier顺序浸提法浸提污泥中的重金属Pb和Zn,对其在堆肥过程中不同形态的变化规律以及无机盐对重金属稳定态的影响进行研究。结果表明:污泥中重金属Pb和Zn的含量均符合国家相关控制标准(GB 18918-2002和CJ248-2007);堆肥处理明显改变了污泥中重金属的形态分布,Pb与Zn的可交换态分别降低了31.15%和14.14%,残渣态分别增加12.79%和16.35%,显著地降低了重金属的生物有效性;分别向污泥中加入不同无机盐后堆肥,其重金属含量均有向稳定态转变的趋势。其中,加入碳酸铵的样品转变率最高,Pb与Zn的稳定态含量最高可达83.95%与81.13%。     

Runoff effect on eutrophic lake water quality and heavy metal distribution in recent littoral sediment

Multivariate statistical methods (hierarchical clustering analysis: HCA, and principal component analysis: PCA) were used to study the influence of runoff and other diffuse pollution sources on lake water chemistry of Hough Park lake in Central Missouri. In addition, heavy metal concentrations in lake littoral sediment were evaluated for enrichment and probable ecological risk. The abundance of macronutrients in the lake water column followed the order: Ca > Mg > TIC > K > Na > S > NO₃ - N > Fe > NH₃ - N > TP. Heavy metal concentrations in the lake water column were below acute and chronic level ecological guidelines. TN:TP ratios (range: 4.1-6.8) revealed nitrogen limitation of algal and other photosynthetic plant growth. The HCA showed two major clusters of similarity between the sampling points suggesting different pollution levels for the clusters. PCA 1, 2 and 3 reflected the influence of natural biochemical processes, atmospheric deposition and runoff respectively on lake water chemistry. The abundance of heavy metals and the normalizing element (Li) in littoral sediment (<63 μm fraction) samples analyzed in decreasing order were: Mn > Zn > Cr > Ni > Li > Cu > Pb > Cd > Hg. The average concentration of Cr, Mn and Ni in littoral sediment fraction exceeded the respective lowest effects level (LEL) threshold limit. Metal bioavailability in sediment fraction was low since the most labile metal species contained between 0% and 11% of the total metal content. Using the risk assessment code (RAC) criteria, only Mn posed a medium risk to the lake system.     

Reduction of mercury emissions from anthropogenic sources including coal combustion

Mercury(Hg)ranks number three,after arsenic(As)and lead(Pb),on the Substance Priority List of the Agency for Toxic Substances and Disease Registry(ATSDR,2019).M...