电厂煤燃烧后元素硒的分布及对环境的贡献

对电厂煤、除尘器飞灰、渣及不同粒径的烟道飞灰中痕量元素硒进行研究.化学分析表明,硒在渣和除尘器飞灰中亏损而在细飞灰中富集,尤其在>19.0μm的飞灰中明显富集,富集系数达到5.15,造成这种现象的原因一是挥发性元素的挥发-凝结作用,二是燃烧产物在燃烧气流中停留的时间,三与飞灰颗粒形态有关,>19.0μm的飞灰中多孔颗粒可能是造成其富集的原因.逐级化学提取实验表明,煤中硒主要具有机相关性(69.7%),这也是硒挥发性高的一个主要原因;物质平衡计算显示煤中16.5%的硒随气流直接排放入大气,细飞灰中的硒只占1.1%,且大部分在>19.0μm的飞灰中,影响范围小,渣中硒对周围环境的影响更小,飞灰中的硒具有一定的迁移性,也许可以用来改善缺硒土壤.     

汞和两种农药复合污染对土壤转化酶活性的影响

通过模拟方法研究了豆磺隆,呋喃丹2种农药与重金属汞(Hg)单一及复合污染对草甸棕壤和黑土4个土壤转化酶活性的影响.结果显示,在试验浓度范围内,土壤添加豆磺隆和呋喃丹后,转化酶变化幅度分别为-12%～7%和-6%～7%,表明2种农药对土壤转化酶的毒性较小;Hg对转化酶最大抑制率为22%～35%,二者之间呈显著的对数负相关关系,表明Hg对转化酶的毒性较大,转化酶在一定程度上可作为Hg污染的监测指标,通过对数方程计算出4个土样的生态剂量(ED₅₀)分别为76.68,727.49,236.52,316.59mg/kg;Hg和2种农药之间普遍存在交互作用,豆磺隆与Hg复合污染引起土壤转化酶最大净变化量(△I)为对照的-12%～15%,呋喃丹和Hg为-25%～-6%,有机质对复合污染产生的毒性有明显的缓冲作用.     

Terrigenous Inputs and Accumulation of Trace Metals in the Southeastern Taiwan Strait

Abstract

Terrigenous inputs and sedimentary fluxes of trace metals were studied to understand the metal sources, transport and sinks in the southeastern Taiwan Strait. the major terrigenous metals come from seven major rivers in the southwestern Taiwan, even though significant fractions of most metals were retained in estuaries. the net fluxes of river borne metals contributed from 65% (Pb) to 92% (Fe, Zn) of total inputs. the remainder was attributed to marine sewage discharges (0.6–6.9%) and atmospheric inputs (5.3–31.5%). Sedimentary fluxes of trace metals were spatially variable as a result of derivation from site-specific sedimentation rates and metal distributions in sediments. in spite of imbalance between sources and sinks of trace metals, an accumulation of metals in the sediment of southeastern Taiwan Strait was found for sites close to Taiwan Island. Surface enrichment of metals in near-shore sediments beginning around 1976 was coincident with a time of industrial boom in Taiwan. the metal enrichment hierarchy was found as (Cd, Pb < Cu < Zn < Mn, Fe).     

Potential application of 2-(6-ethylamino-3-ethylimino-2,7-dimethyl-3H-xanthen-9-yl) benzoic acid phenyl thiourea for mercury determination

Heavy metal contamination of the environment is a public health problem and research to develop new tools for monitoring the environmental impact of these elements is necessary. This study describes the preparation of a rhodamine-based probe 1 and its potential applications for detecting mercuric ion [Hg(II)] in samples from a nutrition media containing Salvinia auriculata. It was observed that an excess of probe 1 led to quenching in the fluorescence/absorption response, which was evidenced by a decrease in the signal when the stoichiometry differed from 1:1. Consequently, this probe is not suitable for quantitative analysis of Hg(II). Also, probe 1 reacts with methylmercury (MeHg) with different stoichiometry than that observed for Hg(II). These results indicate the potential application of probe 1 for qualitative detection of Hg(II) and MeHg in environmental samples.     

Regulation of autophagy in rat hepatocytes treated in vitro with low concentration of mercury

Several proteins are implicated in the regulation of autophagy in cells under various physiological and pathological conditions. Recently it was found that in vitro initiation of autophagy in 5 μM mercuric chloride (HgCl₂) treated rat hepatocytes occurred within 30 min of incubation. The aim of this study was to monitor the autophagy–ubiquitination link to determine the regulatory mechanisms underlying autophagy at a concentration of 5 μM HgCl₂. Autophagic cell death was evidenced by the presence of LC3B positive hepatocytes throughout the incubation period of 4 hr. Autophagosome maturation occurred following 1 hr of metal treatment accompanied by an enhanced expression of several regulatory proteins such as p62, Keap1, and caspase-8, which drive the hepatocytes toward autophagy. In addition, the rate of increase in down-regulation in a p38 expression was significantly higher than that of extracellular signal-regulated kinase (ERK) at 1 hr incubation, followed by a significant decline in the p38 level at 2 and 4 hr following metal treatment. In contrast, the expression of ERK remained higher than that of p38 at 2 and 4 hr. Data indicate that intracellular activation of the major regulatory proteins such as LC3B, caspase-8, Keap1, p62, ERK, and p38 modulates autophagy through ubiquitination in rat hepatocytes exposed to low concentrations of Hg.     

青岛秋冬季PM1中金属元素污染特征及健康风险评估

于2018年11月1日至2019年1月31日（OP_2018-2019）和2019年11月1日至2020年1月20日（OP_2019-2020）在青岛对PM₁进行了连续两年秋冬季逐日采集.将观测期划分为4个空气质量等级（Ⅰ级、Ⅱ级、Ⅲ级和Ⅳ级）,分析了PM₁中金属元素浓度特征及来源,评估了不同人群的非致癌风险（Zn、Pb、Mn、Cu和V）和致癌风险（As、Cr、Ni、Cd和Co）.结果表明,与OP_2018-2019相比,OP_2019-2020期间不同空气质量等级下金属元素总浓度变化与Ca、K和Al浓度变化有关,受扬尘源和生物质燃烧源影响较大.与OP_2018-2019相比,OP_2019-2020期间不同空气质量等级下V浓度分别下降19.0%、60.5%、82.7%和77.5%.推测与船舶国内排放控制区域（DECA）政策实施有关,青岛周边海域船舶改换燃油品质,导致V浓度大幅降低.由富集因子、比值法和气流后向轨迹结果进一步表明V浓度变化主要受DECA政策影响.然而,实施DECA政策后,V/Ni值作为判断区域内受船舶源影响的限值,需进一步探究.由健康风险评估结果表明,OP_2018-2019和OP_2019-2020期间非致癌元素Mn的危险系数范围为0.07~1.22,建议加强管控含Mn污染源的排放.OP_2018-2019和OP_2019-2020期间不同空气质量下As、Cd的终生致癌风险概率（ILCR）值低于10^-4,但高于10^-6,表明存在致癌概率,但仍可接受.OP_2018-2019期间空气质量为Ⅳ级时,Cr的ILCR值高于10^-4,存在致癌风险.     

大气汞的来源、形态及环境过程研究现状

对大气中汞的主要研究内容进行概述，包括大气汞的来源与释放量、大气反应与传输及大气-水、土、植物界面的交换等过程，并指出大气环境研究中需进一步完善的领域。     

贵州省务川汞矿区土法炼汞过程中汞释放量的估算

通过对酸性水溶液、含Fe³⁺水溶液、含Fe²⁺水溶液、细菌菌液和细菌培养基水溶液脱除二氧化硫的实验,探讨了微生物液相氧化二氧化硫的途径.以液相中SO₄^2-浓度考察了Fe³⁺浓度、Fe²⁺浓度、进口SO₂浓度以及温度对脱硫成酸的影响.微生物脱硫有2种机制:一是直接氧化作用,即氧化亚铁硫杆菌(Thiobacillus ferrooxidans)将S(IV)氧化成S(VI);二是间接催化氧化,氧化亚铁硫杆菌在酸性条件下具有快速氧化Fe²⁺成Fe³⁺,增强Fe³⁺对SO₂的液相催化氧化能力,研究表明微生物脱硫以间接催化氧化为主.在浓度0～1.2g/L之间,Fe³⁺和Fe²⁺浓度越高,脱硫效果越好,氧化亚铁硫杆菌表现出对Fe³⁺/Fe²⁺体系氧化SO₂的强化效果.入口SO₂浓度越高,细菌脱硫效率越低,但液相中SO₄^2-浓度随进口SO₂浓度增加变化不大.温度对微生物脱硫影响较大,最佳脱硫温度为30～40℃.     

Reduction of availability of trace metals in urban soils using inorganic amendments

Urban soils in medium- and large-sized cities generally have shown elevated contents of environmentally important trace metals (e.g. lead, copper, zinc). Such high concentrations in soils of green areas, mainly recreational areas, can be a source of potentially toxic elements and pose a risk for human health. Thus the availability of these contaminants is an essential control parameter, as it indicates potential plant uptake and their transfer to humans via inhalation of suspended dust, or direct ingestion (i.e. hand to mouth pathway), or consumption of contaminated foodstuff. Young children are the most sensitive segment of the population. Addition of amendments to the soil is a feasible technique to reduce the availability of trace metals. Accordingly, four urban soils of green areas of Seville (Spain), with relatively high lead contents and moderate copper and zinc contents, were amended in the laboratory with four inorganic materials [acid zeolite (AZ), sodium zeolite (SZ), Slovakite (SL), apatite (AP)], at two rates (1%, 5% w/w) and incubated for 1 year. Significant decreases in EDTA-extractable metal contents were observed in some of the treatments after adding the amendments even before the incubation begun, mainly for SL treatments. The amendment that produced the longest lasting immobilisation effect, compared to control treatments, was AZ at the higher rate. The effects of SZ and SL tended to decrease with time, while the AP effect was almost negligible after 3 months of ageing. This study confirms the feasibility of using certain inexpensive soil amendments to at least temporarily immobilise metals in urban soils for the purpose of protecting human health, especially that of young children.     

Transgenic Spartina alterniflora for phytoremediation

Perennial monoculture forming grasses are very important natural remediators of pollutants. Their genetic improvement is an important task because introduction of key transgenes can dramatically improve their remediation potential. Transfer of key genes for mercury phytoremediation into the salt marsh cordgrass (Spartina alterniflora) is reported here. S. alterniflora plays an important role in the salt marsh by cycling of␣elements, both nutrients and pollutants, protects the coastline from erosion, is a keystone species in the␣salt marsh supporting a large food web, which in turn supports a significant segment of economy, including tourism, has an impact on cloud formation and consequently on global weather, and is thus an ecologically important species relevant for our life-support systems. Embryogenic callus of S. alterniflora was co-inoculated with a pair of Agrobacterium strains LBA4404 carrying the organomercurial lyase (merB) and mercuric reductase (merA) genes, respectively, in order to co-introduce both the merA and the merB genes. Seven stable geneticin resistant lines were recovered. The presence of merA and merB genes was verified by PCR and Southern blotting. All but one transgenic lines contained both the merA and the merB sequences proving that co-introduction into Spartina of two genes from separate Agrobacterium strains is feasible and frequent, although the overall frequency of transformation is low. Northern blotting showed differences in relative expression of the two transgenes among individual transformants. The steady-state RNA levels appeared to correlate with the phenotype. Line #7 showed the highest resistance to HgCl₂ (up to 500 μM), whereas line #3 was the most resistant to phenylmercuric acetate (PMA). Wild-type (WT) callus is sensitive to PMA at 50 μM and to HgCl₂ at 225 μM.