Anthropogenic Mercury Release Flow in China

China is the largest emitter of anthropogenic mercury worldwide. Implementation of the Minamata Convention on Mercury will significantly impact the development, use, and management of mercury resources. Chinese mercury management policies require significant adjustment. There is an urgent need to develop a current national mercury inventory to estimate mercury inputs and outputs by source category, and to clarify the distributions to various environmental scenarios. Here, the mercury releases are quantitatively analysed to facilitate the implementation of strategic mercury management policies in China. First, the mercury inputs and outputs by source categories in 2016 are quantified and then the mercury distributions to various environmental and intermediate sinks are estimated. The total mercury input was 5,116 t in 2016, of which 77% was attributable to mineral production. In total, 3,083 t were released into various environmental and intermediate reservoirs. Of this total, 53.8 % was intentional uses, followed by extraction and combustion (26.5%), and mineral production (19.6 %); 1,501 t were released into air, water, and land, of which extraction and combustion accounted for 48.6 % followed by mineral production (25.7 %) and intentional uses (25.6 %)

Developing a dataset for the expected anthropogenic mercury release in China in response to the Minamata convention on mercury

This paper contains supplementary data in support of a research paper published [1] regarding the expected anthropogenic mercury release in China in response to the Minamata Convention on Mercury (MCM). The dataset provided within this article contains a set of excel spreadsheets. Each spreadsheet contains filtered (collected) and analysed data, i.e., parameters, collected data, calculated and summarized results for mercury distribution by the category of mineral production, intentional uses, secondary metal production, extraction and combustion, and waste treatment in a specific year. The collected (filtered) data in this article consist of the input factor (IF), activity rate data (ARD), output scenario (OS), initial distribution factor (iDF), and redistribution factor (rDF). IF was from the default IF in the United Nations Environment Programme (UNEP) Toolkit Level 2 and published scientific papers. ARD was obtained from the U.S. Geological Survey database, China Statistical Yearbooks, and published scientific papers. The OS content was from the default OS in the UNEP Toolkit Level 2 and published scientific papers. iDF was from the default distribution factor (DF) in the UNEP Toolkit Level 2 and published scientific papers. rDF was from published scientific paper. The mercury input was calculated using IF and ARD. The mercury release to different media in the initial distribution step was calculated using the mercury input and iDF. The release of mercury to the final sinks in the redistribution step was calculated using the amount of sector-specific treatment/disposal, product or by-product, and rDF. The dataset with combination of the collected (filtered) and analyzed data can contribute to an understanding of differences in anthropogenic mercury release before and after implementation of the MCM, especially considering technology transformation in China. Government policymakers involved in hazardous waste management, especially those working on MCM, and engineers and scientists interested in hazardous waste management may benefit from these data. The data can be used for identifying the environmental impact of anthropogenic mercury release before and after the MCM in China. The data can facilitate the creation of strategic management policies for mercury as the MCM is implemented in China

Effective lipid extraction from undewatered microalgae liquid using subcritical dimethyl ether

[Background] Recent studies of lipid extraction from microalgae have focused primarily on dewatered or dried samples, and the processes are simple with high lipid yield. Yet, the dewatering with drying step is energy intensive, which makes the energy input during the lipid production more than energy output from obtained lipid. Thus, exploring an extraction technique for just a thickened sample without the dewatering, drying and auxiliary operation (such as cell disruption) is very significant. Whereas lipid extraction from the thickened microalgae is complicated by the high water content involved, and traditional solvent, hence, cannot work well. Dimethyl ether (DME), a green solvent, featuring a high affinity for both water and organic compounds with an ability to penetrate the cell walls has the potential to achieve this goal. [Results] This study investigated an energy-saving method for lipid extraction using DME as the solvent with an entrainer solution (ethanol and acetone) for flocculation-thickened microalgae. Extraction efficiency was evaluated in terms of extraction time, DME dosage, entrainer dosage, and ethanol:acetone ratio. Optimal extraction occurred after 30 min using 4.2 mL DME per 1 mL microalgae, with an entrainer dosage of 8% at 1:2 ethanol:acetone. Raw lipid yields and its lipid component (represented by fatty acid methyl ester) contents were compared against those of common extraction methods (Bligh and Dryer, and Soxhlet). Thermal gravimetry/differential thermal analysis, Fourier-transform infrared spectroscopy, and C/H/N elemental analyses were used to examine differences in lipids extracted using each of the evaluated methods. Considering influence of trace metals on biodiesel utilization, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy analyses were used to quantify trace metals in the extracted raw lipids, which revealed relatively high concentrations of Mg, Na, K, and Fe. [Conclusions] Our DME-based method recovered 26.4% of total raw lipids and 54.4% of total fatty acid methyl esters at first extraction with remnants being recovered by a 2nd extraction. In additional, the DME-based approach was more economical than other methods, because it enabled simultaneous dewatering with lipid extraction and no cell disruption was required. The trace metals of raw lipids indicated a purification demand in subsequent refining process

Effective Separation and Recovery of Manganese and Potassium from Biomass Ash by Solvent Extraction

Manganese (Mn) is considered an important, energy-critical metal due to its leading role in the production of electrochemical energy storage devices. One valuable source of Mn is hyperaccumulator plants used for the phytoremediation of contaminated soil. In this study, stems and leaves of ginger (Zingiber officinale), which accumulate Mn at moderate levels (∼0.2 wt %) and potassium (K) at high levels (>5 wt %), were analyzed to assess the potential of recovering metals from this plant. The extraction behaviors of Mn and K were studied using raw and ash samples (100−600 °C). It was crucial to set an appropriate incineration temperature (300 °C) to selectively extract K (∼96%) and Mn (∼90%) using water and nitric acid over two consecutive steps. Additionally, citric acid, a cost-effective and environmentally friendly solvent, was just as effective (∼85%) as nitric acid in extracting Mn. X-ray absorbance nearedge spectroscopy and X-ray diffraction analysis of the ash before and after extractions were applied to elucidate the extraction mechanism. The results revealed that selective extraction of both compounds was possible due to the change in the oxidative state of Mn(II) (soluble in water) into Mn(III) and Mn(IV) (insoluble in water) during sample incineration. Simultaneously, there were complex reactions associated with the changes within potassium carbonate compounds; however, these did not affect the K extraction efficiency

Microalgae preparation and lipid extraction by subcritical dimethyl ether

Biodiesel produced from microalgae is a potential alternative due to the high growth rate of microalgae, the possibility of using nonarable land, and high lipid accumulation rate. Microalgae cultivation, cell harvesting and disruption are the important steps before lipid extraction for the biodiesel. In the co-submission article, the details of the whole process cannot be clearly explained. In this regard, we present the details of methods on parameter of photo-bioreactor for cultivating microalgae, flocculation tests to determine optimal flocculant dosage in harvesting, parameter of Dimethyl ether (DME) subcritical extraction device and full-factorial design for investigating the influence of extraction time, initial water content and DME dosage on the extraction performance. It will allow researchers to reproduce these experiments. • The method shows a cell disruption assisted lipid extraction by subcritical dimethyl ether. • Model is built from full-factorial design to investigate multi-factor influence. • Differential scanning calorimetry can be applicable to measure free water content

Future trends of excess mercury in Asia in response to Minamata Convention on Mercury

Owing to rapid industrialization, Asia has become the main source of mercury emissions and a significant net importer of mercury. Therefore, the situation regarding excess mercury in Asia needs to be better understood. In this study, mercury flows and excess mercury in 2010–2050 in Asian regions, with a particular focus on China, are assessed under updated assumptions. The excess mercury in China in 2030 and 2050 is estimated to be 125 and 284 tons, respectively. The cumulative excess mercury in China will reach around 10,000 tons in 2050 under the assumption of no export of it in the years 2010–2050. In addition, the year in which mercury reaches a surplus in Asia (excl. China) is estimated to be 2039. The mercury supply in Asia strongly depends on the usage of excess mercury in China. It is estimated that mercury supplies will be insufficient in Asia until at least 2017. These predictions should support decision-making and planning for long-term storage capacity, discussions of regional coordination, securing of technical support, and development of the basic design of related facilities

Role of Intrapancreatic SPINK1/Spink3 Expression in the Development of Pancreatitis

Studies on hereditary pancreatitis have provided evidence in favor of central role for trypsin activity in the disease. Identification of genetic variants of trypsinogen linked the protease to the onset of pancreatitis, and biochemical characterization proposed an enzymatic gain of function as the initiating mechanism. Mutations of serine protease inhibitor Kazal type 1 gene (SPINK1) are shown to be associated with hereditary pancreatitis. We previously reported that Spink3 (a mouse homolog gene of human SPINK1) deficient mice showed excessive autophagy, followed by inappropriate trypsinogen activation in the exocrine pancreas. These data indicate that the role of SPINK1/Spink3 is not only trypsin inhibitor, but also negative regulator of autophagy. On the other hand, recent studies showed that high levels of SPINK1 protein detected in a serum or urine were associated with adverse outcome in various cancer types. It has been suggested that expression of SPINK1 and trypsin is balanced in normal tissue, but this balance could be disrupted during tumor progression. Based on the structural similarity between SPINK1 and epidermal growth factor (EGF), we showed that SPINK1 protein binds and activates EGF receptor, thus acting as a growth factor on tumor cell lines. In this review, we summarize the old and new roles of SPINK1/Spink3 in trypsin inhibition, autophagy, and cancer cell growth. These new functions of SPINK1/Spink3 may be related to the development of chronic pancreatitis

Microscopic synchrotron X-ray analysis of mercury waste in simulated landfill experiments

Mercury enters into the environment or waste streams because it is present as an impurity in natural minerals. Mercury must be appropriately managed as an hazardous waste. In this study, a waste layer of artificial mercury sulfide mixed with incinerator ash and sewage sludge compost in a simulated landfill experiment for 5 years was analyzed using microscopic synchrotron X-ray to obtain basic knowledge of mercury behavior in a landfill. Mapping by synchrotron X-ray revealed the distribution of mercury-containing particles in the waste layer. In most cases, the movement of mercury sulfide was not considered significant even within a microscopic range; however, water flows could enhance the movement of mercury sulfide particles. When disposing of mercury sulfide, “concentrated placement” or solidification, rather than mixing with other wastes, was more effective at preventing mercury leaching in lysimeters. The chemical form of mercury sulfide in each lysimeter was confirmed by X-ray absorption fine structure (XAFS) analysis, which showed that most of the mercury was present as metacinnabar and had not undergone any changes, indicating that it was extremely stable. The microscopic synchrotron X-ray analysis proved very useful for studying the behavior of mercury waste in a simulated landfill experiment

Mercury emission profile for the torrefaction of sewage sludge at a full-scale plant and application of polymer sorbent

We evaluated mercury (Hg) behavior in a full-scale sewage sludge torrefaction plant with a capacity of 150 wet tons/day, which operates under a nitrogen atmosphere at a temperature range of 250–350 °C. Thermodynamic calculations and monitoring results show that elemental Hg (Hg⁰) was the dominant species in both the pyrolysis gas during the torrefaction stage and in the flue gas from downstream air pollution control devices. A wet scrubber (WS) effectively removed oxidized Hg from the flue gas and moved Hg to wastewater, and an electrostatic precipitator (ESP) removed significant particulate-bound Hg but showed a limited capacity for overall Hg removal. Hg bound to total suspended solids had a much higher concentration than that of dissolved Hg in wastewater. Total suspended solid removal from wastewater is therefore recommended to reduce Hg discharge. Existing air pollution control devices, which consist of a cyclone, WS, and ESP, are not sufficient for Hg removal due to the poor Hg⁰ removal performance of the WS and ESP; a further Hg0 removal unit is necessary. A commercial packed tower with sorbent polymer catalyst composite material was effective in removing Hg (83.3%) during sludge torrefaction

Effect of pH on the performance of an acidic biotrickling filter for simultaneous removal of H₂S and siloxane from biogas

Acidic biotrickling filters (BTF) can be used for simultaneous removal of hydrogen sulfide (H₂S) and siloxane from biogas. In this study, the performance of a BTF under different acidic pH conditions was investigated. The removal profile of H₂S showed that 90% of H₂S removal was achieved during the first 0.4 m of BTF height with down-flow biogas. Decamethylcyclopentasiloxane (D5) removal decreased from 34.5% to 15.6% when the pH increased from 0.88 to 3.98. Furthermore, the high partition coefficient of D5 obtained in under higher pH condition was attributed to the higher total ionic strength resulting from the addition of sodium hydroxide solution and mineral medium. The linear increase in D5 removal with the mass transfer coefficient (kL) indicated that the acidic recycling liquid accelerated the mass transfer of D5 in the BTF. Therefore, the lower partition coefficient and higher kL under acidic pH conditions lead to the efficient removal of D5. However, the highly acidic pH 0.9 blocked mass transfer of H₂S and O2 gases to the recycling liquid. Low sulfur oxidation activity and low Acidithiobacillus sp. content also deteriorated the biodegradation of H₂S. Operating the BTF at pH 1.2 was optimal for simultaneously removing H₂S and siloxane