CHemical and Biological Assessment of an Urban, Estuarine marsh in Northeastern New Jersey USA

Oritani Marsh in the Hackensack Meadowlands of urbanized northeastern New Jersey USA was assessed in 2000 for vegetation, soil/sediment chemistry, abundance/diversity of benthic invertebrates, and bird and mammal usage. Vegetatively, both marsh and uplands are dominated by tall, dense Phragmites australis. Small patches (less than 2 hectares total) dominated by Spartina spp. were found at the lowest elevations. Soil/sediment cores were sliced into 5 intervals and analyzed for metals, pesticides and volatile/semivolatile organic compounds. Thirteen locations had at least one chemical above Long et al.’s [Environmental Management, 19, 1995, 81--97] “Effects Range-Median” (ERM). Seven metals and nine organics exceeded ERM in at least one sample, with mercury showing the most exceedances. The surface 15 cm interval was generally more contaminated with metals than the 15 to 30 cm interval; the reverse was true for semivolatile organic compounds. Twenty taxa of benthic macroinvertebrates were collected, with each location producing from 1 to 9 taxa. Abundance ranged from 11 to 3,889 individuals/m². Number of taxa was moderately (r ² between 0.40 and 0.70) negatively correlated with zinc, beryllium, nickel and arsenic concentrations; no other chemical’s r ² was above 0.25. Diversity was moderately negatively correlated with arsenic and beryllium. These correlations were unexpected: zinc, beryllium, nickel and arsenic were not the chemicals found at the highest concentrations relative to benchmarks. Number of taxa, abundance and diversity were moderately (negatively) correlated with elevation; organic carbon was moderately (positively) correlated with abundance. All other correlations were weak (r ² < 0.35). Live traps captured only one mammal species, the meadow jumping mouse. Bird observations revealed 39 species, dominated by a few common species.     

Environmental assessment of mercury dispersion, transformation and bioavailability in the Lake Victoria Goldfields, Tanzania

Environmental dispersion and transformation of mercury discharged from gold mining operations has been investigated in field and laboratory studies in order to provide better understanding of the degree of mercury (Hg) pollution and bioavailability in the Lake Victoria goldfields (LVGF) ecosystems. This paper reviews results already published elsewhere and presents additional data on Hg dynamics in the LVGF. Studies conducted at the Mugusu and Rwamagaza artisanal mines indicated different degrees of Hg contamination and dispersion in environmental matrices. Mercury concentration in contaminated river sediments near the Mugusu mine varied from 6.0 to 0.5 mg/kg on a dry weight basis. The highest Hg contamination levels (165-232 mg/kg) were associated with mine tailings at the Rwamagaza mine. Mercury concentrations in fish representing different dietary habits on the southwestern shore of Lake Victoria at the Nungwe Bay were very low (2-35 microg/kg) and thought to represent background levels. These and other results suggested that the use of Hg in gold extraction in the LVGF has not caused high Hg levels in lake fish. The study of Hg in lichens showed Parmelia lichen to be an effective bioindicator for atmospheric Hg contamination due to Hg emissions from gold-amalgam firing and purification operations. The Hg levels in the lichens around the Mugusu mine ranged from 3.1 to 0.1 microg/g; the highest levels were recorded in the lichens sampled close to gold-amalgam processing sites. The regional background level in the Parmelia lichen was 0.05-0.10 microg/g, with a mean level of 0.07 microg/g. Studies of Hg transformation in the mine tailings revealed unexpectedly high methylmercury (MeHg) levels in the tailings (629-710 ng/g), which indicated that oxidation and methylation of metallic Hg in the tailings occurred at significant levels under tropical conditions. Re-equilibration of the tailings with freshwater (FW) indicated the MeHg was firmly bound in the tailings and therefore very little MeHg was released to the water column (0.2-1.5 ng/L). The methylation of Hg in tropical loamy clay soil contaminated with HgCl(2) (5 mg Hg/kg) yielded MeHg concentrations of 11 and 14 ng/g when inundated with seawater and FW, respectively, for 4 weeks. Little MeHg was transferred from the soil to the equilibrated water (< or = 0.4 ng/L). Atmospheric exposure of the soil pre-inundated with FW resulted in net degradation of MeHg during the 1st week of exposure, followed by net production and accumulation of MeHg in the soil (up to 15.5 ng/g) during atmospheric desiccation. Mercury uptake by fish from the Hg(0)-contaminated aquatic sediment-tailings system in the aquarium experiment was found to be low, suggesting the low availability of MeHg for bioaccumulation in the system. These and other results provide useful insights into Hg transformation, mobility and bioavailability in tropical aquatic systems affected by Hg pollution from gold mining operations.     

Health and environmental assessment of mercury exposure in a gold mining community in Western Mindanao, Philippines

The small-scale gold mining activities using mercury began in the late 1980s in Sibutad, Western Mindanao. It is located very near the Murcielagos Bay with tailing ponds directly discharging into bodies of water. This cross-sectional study aimed to determine the health and environmental effects of gold mining activities on the community. Residents were randomly selected and classified into two groups, namely, the directly exposed and indirectly exposed populations using a set inclusion criteria. Complete medical and laboratory examinations were performed. Environmental and biologic samples were collected for total mercury and methylmercury determinations. The results showed that the directly exposed group had significantly higher mean blood total mercury and methylmercury levels in comparison with the indirectly exposed population. Although there were no significant differences between hair total mercury and methylmercury levels, there was a trend for higher levels of these biomarkers among the directly exposed residents as compared with the unexposed group. The absence of statistically significant differences may be attributable to the small sample size. Ambient air quality monitoring for mercury exceeded the allowable levels. However, levels of mercury in drinking water and sediments were within allowable limits. Frequency of gastrointestinal complaints was significantly associated with elevated hair methylmercury levels (p=0.02). Also, there appears to be a trend towards higher blood total mercury levels and frequency of gastrointestinal complaints (p=0.09). An interesting finding in this study was the increasing incidence of elevated diastolic blood pressure with elevated hair total mercury levels (p=0.07). Mercury storage at home is a risk factor.     

新疆石化工业区颗粒物含水量和酸度对二次无机组分形成的影响

大气二次污染物是新疆独山子区大气污染物的重要组成部分,研究大气中二次组分的转化过程对区域大气污染治理有着重要意义.对新疆独山子区2015年9月至2016年7月采集到的样品进行水溶性组分分析.结果表明,水溶性无机离子(TWSIs)表现出与PM_(2.5)一致的季节变化,为冬季(67.86μg·m~(-3))秋季(13.77μg·m~(-3))春季(10.09μg·m~(-3))夏季(4.85μg·m~(-3));冬季二次无机离子(NH~+_4、SO~(2-)_4和NO~-_3)占TWSIs的98%;结合气溶胶热力学模型(E-AIM)探讨独山子区大气颗粒污染物中颗粒相含水量以及颗粒酸碱性;表明独山子区颗粒物呈酸性,年均原位pH为0.81,其中冬季样品的pH(2.93)值最高;颗粒含水季节变化为冬季(331.32μg·m~(-3))秋季(5.91μg·m~(-3))春季(5.46μg·m~(-3))夏季(1.62μg·m~(-3));年均氮氧化率(NOR)和硫氧化率(SOR)分别为0.13和0.47,表明区域污染物存在二次转化;进一步分析表明颗粒相中的硫酸盐质量浓度受到颗粒含水量和颗粒酸碱度的影响较为明显;高的颗粒相含水条件下区域硝酸盐的形成主要以非均相反应为主.     

邢台市秋季PM2.5及水溶性离子污染特征

为研究邢台市秋季PM_2.5污染特征,于2017年10月15日~11月14日在邢台市区对PM_2.5样品进行了采集,并对其中水溶性离子（包括Cl^-、NO₃^-、SO₄^2-、NH₄⁺、Ca²⁺、Na⁺、Mg²⁺、K⁺）进行了分析.结果显示,观测期间邢台市ρ（PM_2.5）平均值为（130.0±74.9）μg/m³,其中水溶性离子质量浓度为（69.8±11.4）μg/m³,占ρ（PM_2.5）的53.3%,NO₃^-、SO₄^2-和NH₄⁺为主要离子,占水溶性离子比例达到了89.7%. 当污染加重,水溶性离子质量浓度随ρ（PM_2.5）增大而升高,且NO₃^-、NH₄⁺及SO₄^2-占比亦逐渐升高,但其他离子占比随之下降,Ca²⁺尤为明显,表明ρ（PM_2.5）升高时主要受二次无机转化影响;观测期间SOR（硫转化率）与NOR（氮转化率）的平均值分别为0.36和0.25,表明秋季SO₂与NO₂转化速率较强,二次无机污染严重,另外SOR及NOR与温度及相对湿度呈正相关,且SOR对二者更为敏感;邢台市秋季PM_2.5呈弱碱性,NH₄⁺主要以（NH₄）₂SO₄和NH₄NO₃的形式存在;ρ（NO₃^-）/ρ（SO₄^2-）平均值为2.13,表明移动源对秋季大气颗粒物的来源贡献较大;PMF分析结果表明,二次转化源、燃烧源及扬尘源为邢台市秋季PM_2.5中水溶性离子的主要来源.     

Effects of SO2 and H2O on low-temperature NO conversion over F-V2O5-WO3/TiO2 catalysts

F-V_2 O_5-WO3/Ti02 catalysts were prepared by the impregnation method.As the content of F ions increased from 0.00 to 0.35 wt.%,the NO conversion of F-V_2 O_5-WO_3/TiO_2 catalysts initially increased and then decreased.The 0.2 F-V_2 O_5-WO_3/TiO_2 catalyst(0.2 wt.% F ion)exhibited the best denitration(De-NOx) performance,with more than 95% NO conversion in the temperature range 160-360℃,and 99.0% N2 selectivity between 110 and 280℃.The addition of an appropriate amount of F ions eroded the surface morphology of the catalyst and reduced its grain size,thus enhancing the NO conversion at low temperature as well as the sulfur and water resistance of the V_2 O_5-WO3/Ti02 catalyst.After selective catalytic reduction(SCR) reaction in a gas flow containing SO_2 and H_2 O,the number of NH3 adsorption sites,active component content,specific surface area and pore volume decreased to different degrees.Ammonium sulfate species deposited on the catalyst surface,which blocked part of the active sites and reduced the NO conversion performance of the catalyst.On-line thermal regeneration could not completely recover the catalyst activity,although it prolonged the cumulative life of the catalyst.In addition,a mechanism for the effects of S02 and H_2 O on catalyst NO conversion was proposed.     

烟花爆竹燃放对大气污染物及PM2.5组分影响

为了解烟花爆竹燃放对保定市大气污染物和PM_2.5中水溶性离子及有机碳（OC）、元素碳（EC）浓度的影响,对保定市春节期间大气污染物和颗粒物组分的浓度特征进行了分析,并评估了烟花爆竹的贡献.结果表明： 2019年春节期间烟花爆竹集中燃放期PM_2.5、PM₁₀、SO₂、NO₂、CO平均浓度比非集中燃放期分别增加了1.3、1.0、1.1、0.4、0.02倍;保定市春节期间禁燃措施施行后,除夕、初一2d污染物平均浓度、最高浓度和高浓度持续时间均明显下降,集中燃放期烟花爆竹燃放对PM_2.5、PM₁₀和SO₂浓度贡献量从50%左右（2018年、2017年）下降至30%左右（2019年）,其中SO₂贡献量下降幅度超过PM_2.5和PM₁₀;组分分析表明,接待中心站点（主城区）、涿州站点（区县建成区）烟花爆竹燃放期K⁺、Mg²⁺、Cl^-浓度在水溶性离子中的总占比分别为39.3%、51.1%,比非燃放期的占比显著上升;烟花爆竹燃放对PM_2.5中K⁺、Mg²⁺、Cl^-浓度贡献率在50%以上,其中对K⁺贡献占比高达89.0%,涿州站点SO₄^2-、K⁺、Mg²⁺、Cl^-的贡献量分别是接待中心站点的2.2、2.1、1.9、1.8倍,燃放期硫氧化率（SOR）、氮氧化率（NOR）相比于非燃放期均有一定程度的升高;集中燃放期OC、EC浓度较非集中燃放期分别升高了2.5、2.1倍,烟花爆竹燃放对OC影响大于EC.     

砷、汞对植物毒性影响及其迁移富集效应探讨

介绍了自然环境中砷、汞的污染来源与污染现状,探讨了砷、汞对植物生长发育、光合作用和抗氧化能力的影响;为了缓解砷、汞对植物的毒害作用,可以添加新一代植物激素、营养元素和改良剂。分析发现,植物对不同浓度砷和汞的敏感程度并不相同,可利用特定植物的富集作用进行环境修复。当前研究主要集中于植物对砷、汞的吸收和转运生理机制,今后还需要加强对超积累植物分子基础的探索。     

Mercury levels in human population from a mining district in Western Colombia

A biomonitoring study was carried out to examine the adverse impacts of total mercury in the blood(HgB), urine(Hg U) and human scalp hair(HgH) on the residents of a mining district in Colombia. Representative biological samples(scalp hair, urine and blood) were collected from volunteered participants(n = 63) to estimate the exposure levels of THg using a Direct mercury analyzer. The geometric mean of THg concentrations in the hair,urine and blood of males were 15.98 μg/g, 23.89 μg/L and 11.29 μg/L respectively, whereas the females presented values of 8.55 μg/g, 5.37 μg/L and 8.80 μg/L. Chronic urinary Hg(HgU)levels observed in male workers(32.53 μg/L) are attributed to their long termed exposures to inorganic and metallic mercury from gold panning activities. On an average, the levels of THg are increasing from blood(10.05 μg/L) to hair(12.27 μg/g) to urine(14.63 μg/L).Significant positive correlation was found between hair and blood urinary levels in both male and female individuals. Thus the present biomonitoring investigation to evaluate the Hg levels and associated health issues would positively form a framework for further developmental plans and policies in building an ecofriendly ecosystem.     

Mercury flows in large-scale gold production and implications for Hg pollution control

Large-scale gold production(LSGP) is one of the five convention-related atmospheric mercury(Hg) emission sources in the Minamata Convention on Mercury. However, field experiments on Hg flows of the whole process of LSGP are limited. To identify the atmospheric Hg emission points and understand Hg emission characteristics of LSGP, Hg flows in two gold smelters were studied. Overall atmospheric Hg emissions accounted for 10%–17% of total Hg outputs and the Hg emission factors for all processes were 7.6–9.6 kg/ton. There were three dominant atmospheric Hg emission points in the studied gold smelters, including the exhaust gas of the roasting process, exhaust gas from the environmental fog collection stack and exhaust gas from the converter of the refining process. Atmospheric Hg emissions from the roasting process only accounted for 16%–29% of total emissions and the rest were emitted from the refining process. The overall Hg speciation profile(gaseous elemental Hg/gaseous oxidized Hg/particulate-bound Hg) for LSGP was 34.1/57.1/8.8. The dominant Hg output byproducts included waste acid, sulfuric acid and cyanide leaching residue. Total Hg outputs from these three byproducts were 80% in smelter A and 84% in smelter B. Our study indicated that previous atmospheric Hg emissions from large-scale gold production might have been overestimated.Hg emission control in LSGP is not especially urgent in China compared to other significant emission sources(e.g., cement plants). Instead, LSGP is a potential Hg release source due to the high Hg output proportions to acid and sludge.