Landfill is an important atmospheric mercury emission source

Due to the special physical and chemical properties,mercury is a global pollutant which could be aeriallytransported cross the borders[1,2]. Both natural processesand human activities emit mercury to the air. The majoranthropogenic mercury emission source categories arecoal combustion, waste incineration, chlorine-alkali plant,metal smelting and refining and so on[1—3] . Human activi-ties emit not only elemental mercury (Hg0), which has along lifetime in the air, but also reactive gaseous mer…     

Spatial concentration, congener profiles and inhalation risk assessment of PCDD/Fs and PCBs in the atmosphere of Tianjin, China

Polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were monitored in a seasonal passive sampling scheme during June 2008 and January 2009 to investigate the spatial concentration, congener profiles and evaluate the potential inhalation risk in different functional areas in Tianjin, China. The spatial air concentrations and I-TEQs ranged 1.08×10²–8.19×10³ fg m^?3 (average 2.63×10³ fg m^?3) and 4.08–325 fg I-TEQ m^?3 (average 91.4 fg I-TEQ m^?3) respectively for PCDD/Fs. The concentration and I-TEQs of PCBs were 3.08×10⁴–3.01×10⁵ fg m^?3 (average 1.39×10⁵ fg m^?3) and 1.72–49.6 fg I-TEQ m^?3 (average 18.5 fg I-TEQ m^?3). It is obvious that PCB concentrations were several hundred times higher than the PCDD/Fs. However, the ambient air PCDD/Fs contributed a major part to the total toxicity equivalents, varying from 72.7% to 89.0% (average 81.8%). The atmospheric PCDD/F levels were observed to be higher in winter for most of sampling sites in the downtown. Besides, inhalation risk assessment showed that local residents might suffer more risk near the point sources than those in living area, industrial zones and background area in Tianjin City. However, the total daily dioxin intake was approximately several to hundreds of times lower than the WHO criteria, showing relatively low exposure risks from the impact of industry point sources in Tianjin City.     

The contribution of root respiration to soil CO2 efflux in Puccinellia tenuiflora dominated community in a semi-arid meadow steppe

Rising atmospheric CO2 and temperature are altering ecosystem carbon cycling. Grasslands play an important role in regional climate change and global carbon cycle. Below-ground processes play a key role in the grassland carbon cycle because they regulate …     

Size distribution and element composition of dust aerosol in Chinese Otindag Sandland

Dust aerosol is one important component of atmos-pheric aerosols, and plays important roles in the Earth’s climate system and the biogeochemical cycle. Large amounts of dust aerosols produced from windblown soils and deserts are emitted annually into the atmosphere and transported over long distance to downwind land and ocean areas[1]. The deserts and desertification soils in northern China are important sources of East Asia dust aerosols. It is estimated that 800 Mt of dust aerosols emit-t…     

Crystallization kinetics of sea-salt aerosols studied by high-speed photography

Morphological changes with decreasing relative humidity(RH) of supersaturated sea-salt aerosol droplets on a quartz substrate were observed using a high-speed video-camera.Stable gypsum(CaSO4·2H2O) or the metastable hemihydrate(CaSO4·0.5H2O) were precipitated as the RH decreased.The dynamic process of crystal growth under steady-state humidity was studied by controlling the RH;the metastable hemihydrate was precipitated at 70.5%-77.1% RH,and the apparent crystal growth rate was between 1.42 and 2.33 μm3/s.Stable gypsum was formed at 80.7%-82.2% RH,and the apparent crystal growth rate was between 0.70 and 0.81 μm3/s.     

Changes of photosynthetic capacity of some plant species under very high CO2 concentrations in Biosphere 2

Conclusions The initial slope of A/ light curve became steep under high CO₂ (700 μmol · mol^-1) compared with that under low CO₂ (350 μmol · mol^-1) for the C₃ species growing in very high CO₂(>2 200 μmol · mol^-1) for a long period. The light compensation points remained unchanged, but the light saturation points were found increased. The ϕ_m,_app and A_max of the C₃ species increased respectively by 79 % and 80 %, while those of C₄ species decreased by 10% and 14%, respectively. The shape of A/light curve of C₄ species did not change. Such results indicated that C₃ species increased the capacity of photosynthesis, while C₄ did not change, otherwise it decreased a little. This work only compared the changes of capacity in photosynthesis of some species under different CO₂ levels in Biosphere 2. We need further investigation on the effects of high CO₂ on the same species outside Biosphere 2, in order to fully undertand the effects and mechanism of response of plants to the elevated CO₂.     

Hydroperoxides in plants exposed to ozone mediate air pollution damage to alkene emitters

OZONE is phytotoxic: it is damaging to cell integrity and photosynthesis(1,2), causing leaf necrosis(3) and reducing crop yield(4). It has been implicated in forest decline(5), perhaps through interactions with stress ethene(6). Here we show that organic hydroperoxides (ROOH), which are products of ozone-alkene reactions(7-9), are present in the leaves of isoprene-emitting plants after exposure to ozone, but are not found in control plants grown in clean air. On the basis of earlier studies(6,7,10), we suggest that this reaction of ozone with biogenic alkenes to produce toxic ROOH could be one of the mechanisms by which damage to plants occurs. This could be particularly important in areas experiencing acidic deposition, where the stability of ROOH will be enhanced. This model may explain in part the die-back of tree species producing reactive alkenes, such as the red spruce, which emits isoprene(11-15) and monoterpenes(16), and the Norway spruce and silver fir, which are both prolific monoterpene emitters(17).     

Responses of woody plant root and xylem sap ATP to soil drying

The ATP in roots and xylem sap of two woody plant species, Platycladus orientalis and Acacia auriculiformis, subjected to rapid and slow soil drying has been determined employing firefly luciferase ATP assay method (sensitivity is at 10-12 mol ATP L-1). The ATP levels in the two species were 1.6 nmol·gDW-1 and 0.6 nmol·gDW-1 in roots, and 5.6 μmol·m-3 and 8 μmol ·m-3 in xylem sap, respectively. When plants of P. orientalis and A. auriculiformis were subjected to rapid soil drying, respectively, as soil water content (SWC) decreased from the normal level ( 0. 25 g ·gDW-1) to 0. 02 and 0. 06 g ·gDW-1, separately, plant water potential ( ) dropped to -4 and -3.2 MPa, differently, the ATP in roots decreased 99.7% and 42%, respectively . When the rapidly dried soil was watered for up to 6 d, SWC and were found to recover to their normal levels, but ATP content in roots of P. orientalis and A. auriculiformis recovered by 10% and 23%, respectively. When plants of P. orientalis and A. auriculiformis were subjected to slow soil drying, respectively, as SWC was found to decrease from the normal level to 0.1 and 0.13 g·gDW-1, separately, dropped to - 2.5 and - 2 MPa, differently, the ATP content in roots decreased 98% and 38%, respectively. When the slowly dried soil was watered for up to 8 d, ATP levels in roots of P. orientalis and A, auriculiformis recovered by 30% and 24%, respectively. However, ATP concentrations in xylem sap were not directly influenced by either SWC or . The plot dots of xylem sap ATP concentration versus root ATP content were found to be distributed diagonally. It is concluded that ATP in roots is more sensitive in response to SWC changes than that to and root-sourced ATP is a source of that in xylem sap. When plants are subjected to slow soil drying, the ATP levels in both root and xylem sap are higher than that to rapid soil drying.     

1-甲基海因的合成及其晶体结构分析

以甲胺、 氯乙酸钠、 氰酸钠等为原料, 用“一锅法”合成1-甲基海因, 合成总收率为62.9%.单晶经X射线衍射方法解析, 其晶体属于单斜 晶系, P2₁空间群, 其中a=0.558 9(3) nm, b=1.217 6(6) nm, c=0.809 0(4) nm;β=105.330(7)°;V=0.531 0(5) nm³;Z=4, D_c=1.427 mg/m³, μ=0.116 mm^-1, F(000)=240.     

Comparative study of the net exchange of CO<Subscript>2</Subscript> in 3 types of vegetation ecosystems on the Qinghai-Tibetan Plateau

Using the eddy covariance method, from 1 July 2003 to 30 June 2004, we conducted the observation and analysis of ecosystem CO2 flux in 3 types of alpine meadow vegetation （Kobresia humilis, Potentilla fruticosa shrub and Kobresia tibetica swamp meadows） on the Qinghai-Tibetan Plateau. The results show that the Kobresia humilis meadow, the shrub meadow and the swamp meadow＇s highest CO2 uptake rates are 16.78, 10.42 and 16.57 μmol·m^-2·-s^-1 respectively, while their highest CO2 release rates are 8.22, 7.73 and 18.67μmol·m^-2·-s^-1 respectively. The Kobresia humilis meadow and shrub meadow＇s annual atmospheric uptakes are 282 g CO2/m^2 and 53 g CO2/m^2, respectively, while swamp meadow＇s annual atmospheric release is 478 g CO2/m^2. This proves that the Kobresia humilis meadow and the shrub meadow on the Qinghai-Tibetan Plateau have relatively low potential for CO2 uptake and release compared to C4 grasslands, a number of lowland grasslands, and forests. Moreover, swamp meadow has relatively high release potential. This, in turn, reveals clear differences in carbon source/sink between different types of vegetation in the Qinghai-Tibetan Plateau alpine meadow ecosystem. These differences are mainly brought by differences in the vegetations＇ photosynthetic capacity and soil respiration.     

Rice protoplasts isolated directly from mature-embryo-derived calli

Mature-embryo-derived calli of japonica rice (Oryza sativa L) Taipei 309 were used for replicated protoplast isolation experiments. Six out of nine callus lines produced protoplasts with satisfactory yield of 5.20×10⁶–8.96×10⁶ protoplasts/g FW (fresh weight). The remaining three callus lines initiated from seeds of cryopreserved-callus-derived plants had rooty calli, resulting in low yield of protoplasts and a large number of isolated banana-shape intact cells. Viability of protoplasts ranged 87.46%–94.15%. The average size of protoplasts was 207.49–379.04 μm² in different callus lines. Comparitive experiments were also carried out using both calli and suspension culture cells for protoplast isolation. The results demonstrated that protoplast isolation of calli was a substantially simplified and reliable method for preparing rice protoplasts. Jin Deming: born in Jan. 1959, Associated Professor     

Structural diversity and reactivity of d^10 metal- （4-pyridylthio）acetate system

The hydrothermal synthesis and crystal structures of four coordination polymers, namely, 2D [Zn（μ3-ta）（pytaH）]n （1）, 2D [Zn（μ3-pyta）Cl]n （2）, 1D [Cd（μ-pyta）2（H2O）]n （3）, and 3D [Cd（μ3-pyta）（μ-Cl）]n （4） （pyta = （4-pyridylthio）acetate, ta = thioglycolate）, are reported. They are based on （4-pyridylthio）acetate and its derived ligand. The ta^2- ligand present in 1 was generated from an in situ C（sp^2）-S bond cleavage of the pyta ligand. In these compounds, versatile intermolecular interactions, such as close S…S interactions and strong （O-H…O/N/S） or weak （C-H…O/S, C-H…Cl） hydrogen bonding interactions, play an important role in the formation of three-dimensional supramolecular networks in the solid state.     

The first determination of atmospheric phosphine in Antarctica

It is generally thought that phosphine (PH3) concentrations exist at the low ng/m3 level during the night and at the pg/m3 level during daylight in the remote atmosphere of the lower troposphere. The first de- termination of gaseous PH3 on the Antarctic Millor Peninsula is reported in this paper. No PH3 was de- tected in the air samples around 10:00 when it was sunny. However, PH3 was found in all the 10:00 air samples when it was cloudy or light snow with the average of 75.3±28.8 ng/m3 (n=5). It was also found in nearly all the samples around 22:00 with the average of 87.2±70.9 ng/m3 (n=11). Atmospheric PH3 concentrations around 22:00 were generally higher than those around 10:00 in January and they were almost the same in February. In addition, PH3 concentrations around 22:00 showed a downtrend with the decreasing air temperature, suggesting that light intensity and air temperature had an important effect on atmospheric PH3 concentration. It is very surprising to have found that high concentrations of PH3 exist in the Antarctic atmosphere under the influence of strong UV-radiation and light intensity. The tentative analyses show that dry, cold and very clean atmosphere may be very suitable for the PH3 sur- vival and cause the concentration to increase and accumulate in the local atmosphere. New ap- proaches for the PH3 formation and the process of atmospheric chemistry may exist under such an extreme environment. Atmospheric PH3 may also be from the emissions of local sources.     

Concentrations, profiles and gas-particle partitioning of PCDD/Fs, PCBs and PBDEs in the ambient air of an E-waste dismantling area, southeast China

Polychlorinated diebenzo-p-dioxins （PCDDs）, polychlorinated diebenzofurans （PCDFs）, polychlorinated biphenyls （PCBs） and polybrominated diphenyl ethers （PBDEs） were monitored in the ambient air of Taizhou, an E-waste dismantling area of southeast China to evaluate their concentrations, profiles and gas-particle partitioning. The ∑PCDD/Fs concentrations ranged from 2.91 to 50.6 pg/ma, with an average of 14.3 pg/ma. The I-TEQs for PCDD/Fs were in the range of 0.20-3.45 pg/ma, with an average of 1.10 pg/ma, The ∑PCBs concentrations and TEQs ranged from 4.23 to 11.35 ng/ma, 0.050 to 0.859 pg（TEQ）/ma, respectively. The concentrations of ∑PBDEs ranged from 92 to 3086 pg/ma, with an average of 894 pg/ma, The pollution levels of PCDD/Fs, PCBs and PBDEs were higher than other urban sites, which may be associated with the E-waste dismantling activities. The PCDD/Fs were found exclusively in the particle phase whereas PCBs distributed dominantly in the gas phase. The gas-partilce partitioning was also assessed by correlating the gas-particle partition coefficient （Kp） with the subcooled liquid vapor pressure （pL^0）. The measured particulate sorptions of PCDD/Fs, PCBs and PBDEs were compared with the predictions from Junge-Pankow model and Koa absorption model. The Junge-Pankow model well estimated the particulate fractions of PCBs. However, it underestimated the sorptions of PCDD/Fs and overestimated the fractions of PBDEs. The predicted particulate fractions of PCDD/Fs and PCBs from Koa model fitted well with the measured data.     

The compositions, sources, and size distribution of the dust storm from China in spring of 2000 and its impact on the global environment

The average mass concentration of the aerosols in Beijing during the dust storm in the spring of 2000 was ~6000 mg·m^-3, ~30 times as high as that in the non-dust storm days. The enrichment factors of the pollution elements As, Sb and Se were higher than those in the non-dust storm days. This indicated that As, Sb and Se resulted from the pollution sources of those areas, through which the dust storm passed during their long-range transport, in addition to the local pollution sources in Beijing. The enrichment factors of the Pb, Zn, Cd and Cu were much less than those in the non-dust storm days, suggesting that the local pollution sources in Beijing area contributed to them mostly. The enrichment factors of elements Al, Fe, Sc, Mn, Na, Ni, Cr, V and Co were close to 1, showing that these elements originated from crust. The concentration of S in the dust storm was ~10 mg·m^-3, 4 times as high as that in non-dust storm. S in the aerosols resulted from the adsorption of gaseous SO₂ and the consequent transformation on it. The aerosols of the dust storm contained 16.1% and 76.9% of fine particles with the sizes less than 2.1 and 9.0 mm, respectively, while it had a large number of coarse particles. It was noted that a considerable portion of Fe(Ⅱ) was detected from the dust storm. Fe(Ⅱ) could easily dissolve in seawater to be nutrient for phytoplankton and would lead to the increase of the emission of dimethylsulfide (DMS) from the ocean. The feedbacks of Fe coupled with S in atmosphere might be the important mechanism that would affect the primary productivity in Pacific and/or the global climate change.     

Export and remineralization of POM in the Southern Ocean and the South China Sea estimated from 210Po/210Pb disequilibria

Disequilibria between ^210Po and ^210Pb in the upper water and their potential applications as a proxy of particle export and remineralization were examined in the Southern Ocean （station IV3） and the South China Sea （NS44）. ^210po was deficit in surface waters but excessive relative to ^210Pb in subsurface waters. Good positive correlation between ^210Po and particulate organic carbon （POC） indicated deficits and excess of ^210Po resulted from particulate organic matter （POM） export and remJneralization respectively, which was also supported by the decreased δ^13C and increased δ^15N downwards as a result of particle remineralization. On the basis of ^210Po/^210Pb box-model, POC export flux out of the surface waters were 1.2 mmol C. m^-2. d^-1 and 2.3 mmol C. m^-2. d^-1 for station NS44 and IV3, respectively. In the subsurface waters, remineralization fluxes of ^210Po were 0.062 Bq. m^-2.d^-1 and 0.566 Bq.m^-2.d^-1 for station NS44 and IV3 along with the recycle efficiency of 52±26% and 119±52%, respectively. Remineralized fluxes of POM derived from ^210Po and exported POC were 0.6 mmol C.m^-2.d^-1 and 2.7 mmol C. m^-2. d^-1 for NS44 and IV3. This study suggested that ^210Po was a powerful tracer of particle export and remineralization.     

Construction and genetic analysis of mutator insertion mutant population in maize

A total of 26718 M1 plants were ob- tained by crossing the active mutator transposon donor parents (Q105, WW51, 115F, V26-2 and 919J) with the recipient parents (Hz85,W328 with Bz gene and S-Mo17Rf3Rf3). The phenotypes of M1 plants were observed in the field. M1 plants were self-pollinated to develop the mutator insertion-mutagenized M2 seeds. The transposition frequency of the mutator in the genome was calculated based on the spotted aleurone phenotype of the M2 seeds. The results showed that: (1) the mutation frequency of M1 phe- notypes in the field was 0.07 in the population of W328×Mu; (2) the mutation frequency of spotted aleurone seeds on the M2 ears was 0.122 in the population of W328×Mu; (3) five S-cytoplasm male-sterile plants were found among 22500 M1 plants of S-Mo17Rf3Rf3×Mu, with the transposition frequency about 2.2×10?4 per locus. 99 flanking se- quences of mutator transposition were amplified by the modified MuTAIL-PCR, and 59 non-redundant sequences with length around 400 bp were obtained. After bioinformatic analysis, 27 sequences of them could be annotated, using non-redundant nucleotide database of maize, rice, and Arabidopsis. 36 se- quences of them were located on the genetic map of maize by comparative genomics, and several flank- ing sequences of mutator insertion were mapped on the single marker locus. Hotspot sequences of mu- tator transposition were revealed by comparing the homologies between the 9-bp target site duplication of the mutator insertion. The putative functions of 8 flanking sequences of mutator transposition had identity with the functions of their correspondingmarker. The constructed mutator insertion mutant population in maize will facilitate the new gene discovery and functional genomics study in maize.     

Detection of 2,4-dinitrotoluene using hydrogen-bond acidic polymer coated SAW sensor

A strong hydrogen-bond acidic （HBA） polymer linear fluoroalcoholic polysiloxane （PLF）, synthesized by one-step hydrosilylation, was introduced for 2,4-dinitrotoluene （2,4-DNT） detection using surface acoustic wave （SAW） devices. FT-IR spectra and 1H NMR spectra char- acterizations confirmed its molecular structure. Then, PLF was dissolved in chloroform, and spray coated onto a 434 MHz SAW device. And subsequently, the sensitivity and selectivity of the fabricated sensor were studied based on a SAW test platform. To 2,4-DNT of 1 ppm and 100 ppb （for DNT, 1 ppm = 8.1 mg/m3; 1 ppb = 8.1 ;tg/m3）, the responses of the sensor rose 7.7 and 1.5 kHz, respectively. Furthermore, compared with some common interference vapors at 10 mg/m3, the response of the sensor to 2,4-DNT at 1 ppm was 5 times stronger. The sensitive property was attributed to the hydrogen bond interaction between the hexafluoroisopropanol （HFIP） group in PLF and the basic lone electron pairs of nitro-groups in 2,4-DNT. Comparison between the PLF sensor and hydroxyl group functionalized polymer （carbowax and MOBCD）-coated sensors was investigated, and the results showed that the PLF sensor exhibited better sensitivity. In a word, the PLF sensor exhibited fast response, negligible baseline drifts and excellent reversibility, indicating good candidates of HFIP group functionalized HBA polymers for practical nitroaromatic explosives detection.     

Methane emissions from wetlands on the Qinghai-Tibet Plateau

The areal extent of cold freshwater wetlands on the Qinghai-Tibet Plateau (QTP) is estimated at 0.133 × 10⁶ km², suggesting a significant methane potential. Methane fluxes from wet alpine meadows, peatlands,Hippuris vulgaris mires and secondary marshes were 43.18, 12.96, −0.28 and 45.90 mg · m⁻² · d⁻¹, respectively based on the transect flux studies at the Huashixia Permafrost Station (HPS) from July to August 1996. Average CH₄ fluxes in the thaw season were extrapolated at 5.68 g · m⁻² according to the areal percentage of wetland areas in the Huashixia region. The CH₄ fluxes at four fixed sites, representative of similar ecosystems, ranged from −19.384–347.15 mg · m⁻² · d⁻¹, and the average CH₄ fluxes varied from 6.54 to 71.97 mg · m⁻² · d⁻¹ at each site during the observation period from April to September 1997. The CH₄ emissions at each site during the entire thaw season was estimated from 1.21 to 10.65 g · m⁻², displaying strong spatial variations. Seasonal variations of CH₄ fluxes also were observed at four sites: CH₄ outbursts occurred upon the spring thaw in May and June, CH₄ fluxes increased afterwards with rising soil temperatures. Episodic fluxes were observed in summer, which influenced the average CH₄ fluxes considerably. Annual CH₄ emissions from cold wetlands on the QTP were estimated at about 0.7–0.9 Tg based on the distribution of wetlands, representative CH₄ fluxes, and number of thaw days. The centers of CH₄ releasing were located in the sources of the Yangtze and Yellow rivers, and Zoigê Peatlands.     

瓷砖地板接缝与非接缝处氡析出差异的实验研究

为了探究缝隙的存在对建筑结构表面氡析出的影响,采用局部静态法,以机房、客厅、实验室贴瓷砖的地面为对象,测量了瓷砖与瓷砖接缝处的一字缝和十字缝以及非接缝处即瓷砖表面的氡析出率。结果表明:1)接缝处的集氡罩内平衡氡浓度远高于瓷砖表面;2)不同瓷砖表面的氡析出率不同,客厅、机房、实验室分别是0.327 mBq/(m²·s)、0.413 mBq/(m²·s)、0.072 mBq/(m²·s);3)一字缝、十字缝及瓷砖表面的氡析出率相差很大,在机房、客厅、实验室三处地面,一字缝表面氡析出率分别是瓷砖表面的3.19倍,2.43倍,2.25倍,十字缝表面的氡析出率分别是瓷砖表面的7.95倍、11.36倍、6.25倍。