铜陵市降水化学成份及其与大气污染关系分析

监测分析铜陵市降水的主要化学组成，结果表明ＳＯ２－４是降水中阴、阳离子量最高的离子，它是决定降水酸度的主导离子，ＮＯ－３对降水氢离子浓度也有一定影响，且铜陵市降水中ＮＯ－３的量高于一般酸雨区，阳离子中以Ｃａ２＋和ＮＨ＋４的量居高。其中ＳＯ２－４来源于大气中的ＳＯ２，Ｃａ２＋来源于大气中的ＴＳＰ，ＮＯ—３来源于大气中的ＮＯｘ。各单种离子含量高低不能决定降水氢离子浓度，氢离子浓度大小只取决于降水中阴、阳离子平衡状况。电导率是反映降水污染程度的一种指标，实际操作中行之有效，较为便捷。     

牡丹江市污染物浓度变化与气象要素关系分析

利用牡丹江市(2005—2011年)大气污染物(SO2、NO2、PM10)浓度实际监测数据及同期地面气象要素场资料、天气图资料,分析了污染物浓度变化与气象条件的关系。结果表明,夏季降水对污染物的稀释有一定影响,1.0 mm以下降水对污染物的稀释作用不明显。但降水量R≥10 mm时降水对污染物的稀释作用较大,一些污染物浓度减少概率占60%以上。当风速小于1 m/s时,污染物浓度明显偏大,冬季浓度是夏秋季节浓度的2倍多。     

Natural sources of Acid neutralizing capacity in low alkalinity lakes of the precambrian shield

A detailed alkalinity budget was constructed for Lake 239 in the Experimental Lakes Area of northwestern Ontario and for three small watersheds in its terrestrial basin. Alkalinity generation in the lake averaged 118 milliequivalents per square meter per year, 4.5 times as high as the areal rate in the terrestrial basin. Although acid deposition in the area is low, only one of the three terrestrial watersheds was a significant source of alkalinity. A second terrestrial watershed yielded very little alkalinity. The third watershed, which contains a wetland, was a sink for, rather than a source of, alkalinity. An analysis of ion budgets for the lake revealed that more than half of the in situ alkalinity production was by biological rather than geochemical processes. The major processes that generated alkalinity were: biological reduction of SO(4)(2-)(53%), exchange of H(+) for Ca(2+) in sediments (39%), and biological reduction of NO(3)(-) (26%). Comparison with experimentally acidified Lake 223 revealed that alkalinity production by sulfate reduction increased in response to increased inputs of sulfuric acid.     

Precursory chemical changes in ground water: kobe earthquake, Japan

Chloride (Cl(-)) and sulfate (SO(4)(2-)) ion concentrations of ground water issuing from two wells located near the epicenter of the Kobe earthquake in Japan fluctuated before the disastrous magnitude 7.2 event on 17 January 1995. The samples measured were pumped ground water packed in bottles and distributed in the domestic market as drinking water from 1993 to April 1995. Analytical results demonstrate that Cl(-)and SO(4)(2-) concentrations increased steadily from August 1994 to just before the earthquake. Water sampled after the earthquake showed much higher Cl(-) and SO(4)(2-) concentrations. The precursory changes in chemical composition may reflect the preparation stage of a large earthquake.     

辽宁省大气湿沉降变化趋势分析

通过分析2009—2013年辽宁省酸沉降控制指标,得出辽宁省大气湿沉降变化趋势。结果表明,辽宁省总体上酸雨污染并不严重,近5年来呈稳定态势。降水属硫酸型降水,主要离子为Ca2+和SO42-,总体来看,各种离子随时间无显著性变化;SO42-沉降量最大,远高于其他离子,其次是NO3-和Ca2+,各年度湿沉降量有不同程度波动,但总体无显著变化;酸性物质的沉降量高于碱性物质。     

2000-2016年朝鲜植被覆盖动态变化及其驱动力研究

基于MODIS NDVI探究朝鲜植被覆盖的空间分布格局,运用斜率分析法拟合2000-2016年朝鲜植被覆盖动态变化趋势,运用Pearson相关分析法分析朝鲜植被NDVI与气温、降水的相关性,在此基础上,总结了2000-2016年朝鲜植被覆盖动态变化规律及其驱动因素.结果表明:朝鲜植被覆盖空间分布不均,北部高原、山地区以及中东部山地丘陵区NDVI值最高;西、南海岸地带,平原地区以及东部沿海区NDVI值最低.朝鲜植被生长季NDVI整体上呈减少趋势,但局部有增加趋势,空间差异明显;其中减少面积为39 161 km2,占国土面积的31.9%,增加面积为28 972 km2,占国土面积的23.6%;生长季各月整体上均呈减少趋势,减少幅度5月最大,7月次之,9月最小.植被变化与气温、降水存在相关性,并存在一定程度的滞后性;年际受气温影响略大,年内9月植被与前期1月、前期与同期累积气温存在显著相关性,与当月、前期与同期累积降水存在显著相关性.     

气相转化-化学发光法测定土壤中的亚硝态氮

试验探究了将亚硝态氮(NO_2~-)还原转化为一氧化氮(NO)气体与化学发光法检测NO相结合的方法(气相转化-化学发光法,简称NC法)对土壤NO_2~-含量测定的适用性。在室温条件下,采用浓度为50%的冰醋酸提供酸性条件,以抗坏血酸为还原剂,将NO_2~-还原为NO气体,生成的NO被高纯氮气载入化学发光法氮氧化物分析仪的NO检测通道,实时记录NO信号值并积分信号峰面积,通过已知NO_2~-浓度系列的标准曲线,确定样品中的NO_2~-浓度。结果显示:NO信号值的峰面积与样品的NO_2~-浓度显著正相关(P0.01),线性检测范围为2~500μg·L~(-1)(以纯N计,下同),检出限为2μg·L~(-1),对土壤NO_2~-浓度的检出限为10μg·kg-1(以水土比为5∶1计),优于比色法的检出限15μg·kg-1;重复测定10次50μg·L~(-1)标准溶液的峰面积变异系数为1.2%,精度为1.2μg·L~(-1)(95%置信区间),对应的土壤NO_2~-浓度检测精度为6μg·kg-1,优于比色法的检测精度11μg·kg-1;检测已知浓度NO_2~-的回收率为90%~97%。与比色法相比,NC法测定酸性土壤NO_2~-浓度的准确度相当,精度更优,但该方法测定碱性土壤NO_2~-浓度的结果偏高,可能是碱性土壤中大量的Ca~(2+)、SO_4~(2-)和CO_3~(2-)对测定有干扰,而且NC法测定NO_2~-浓度的分析时间较比色法长,单个样品需8~15 min。     

Global transport of organic pollutants: ambient concentrations in the remote marine atmosphere

Concentrations of organic pollutants in the air and in precipitation have been measured at Enewetak Atoll in the North Pacific Ocean. These data from a site removed from industrial and human activity indicate the present concentrations of synthetic organic pollutants in the atmosphere and establish the long-range atmospheric transport of organic pollutants to remote marine areas. Hexachlorobenzene and hexachlorocyclohexane isomers are present in the remote marine atmosphere. Polychlorobiphenyls, total DDT, dieldrin, chlordane, and two phthalate ester plasticizers were also found in the samples. The concentrations of pollutants in the atmosphere remote from continental sources are good measures of the minimum concentrations of air pollutants on Earth.     

Acid rain: china, United States, and a remote area

The composition of precipitation in China is highly influenced by fossil fuel combustion and agricultural and cultural practices. Compared to the eastern United States, precipitation in China generally has higher concentrations of sulfate, ammonium, and calcium. Wet deposition rates of sulfur in China are 7 to 130 times higher than those in a remote area in the Southern Hemisphere. In many areas of the world, significant ecological changes have occurred in ecosystems that have acid deposition rates substantially less than those currently existing in China.     

冬季供暖对沈阳市各功能区4种大气污染物浓度的影响

[目的]研究冬季供暖对沈阳市不同功能区4种大气污染物浓度的影响。[方法]根据沈阳市2013年全年11个监测点位的PM10、PM2.5、SO2、NO2实时监测数据,分析4种污染物浓度的月变化规律,并应用主成分分析方法对供暖期和非供暖期该市6类功能区4种污染物对各功能区的影响进行分析。[结果]污染物PM10、PM2.5、SO2的浓度受供暖影响月变化明显,NO2的浓度受供暖及降水的双重影响月变化规律与其他3种污染物有较大不同;供暖期工业区各类污染物浓度最高,商业交通居民混合区供暖期和非供暖期各类污染物浓度均较高,供暖期农村和风景名胜区较其他点位污染物浓度最低;农村、商业交通居民混合区点位NO2浓度最高。[结论]该研究可为进一步调控与治理沈阳市大气污染提供理论支撑。     

落叶前根外追肥对苹果休眠期营养状况的影响

本文于落叶前向苹果树根外追施矿质肥料,落叶后采样测定了氨基酸、可溶性糖和Ｐ、Ｋ、Ｂ、Ｃａ的含量。结果表明,喷含Ｃａ２＋、Ｋ＋、ＳＯ２－４、Ｈ２ＰＯ－４、ＮＯ－３及尿素等肥料均使粗根中氨基酸含量下降,除ＳＯ２－４外其它肥料能促进氨基酸由长枝下运至根系;ＫＮＯ３、Ｂ使根枝中可溶性糖含量增加,而Ｋ２ＳＯ４、ＣａＳＯ４、Ｃａ（ＮＯ３）２、ＫＨ２ＰＯ４使其含量下降;根外追肥促进Ｐ在粗根和枝条中贮存,其效果依次是：ＫＨ２ＰＯ４＞Ｋ２ＳＯ４＞尿素＞ＫＮＯ３,ＫＨ２ＰＯ４、尿素促进Ｃａ在短枝中的贮藏;Ｂ在喷肥后略有减少;根外追肥对Ｋ＋在粗根贮藏影响不显著。     

长沙酸沉降现状研究

根据近几年降水监测数据,分析了长沙酸雨污染状况。结果表明,长沙市酸雨危害较为严重,降水酸度有明显的季节性变化;降水中主要阴离子是SO4和NO3,SO4含量较高,但是NO3含量逐年上升,致酸作用明显应该受到重视;长沙酸雨有加重的趋势。     

Disulfate ion as an intermediate to sulfuric Acid in Acid rain formation

The oxidation of the bisulfite ion by dissolved oxygen to produce sulfate ion involves the formation of a previously undetected intermediate. This intermediate has a fairly strong Raman band at 1090 wave numbers and a weak Raman band at 740 wave numbers, both of which are probably due to sulfur-oxygen stretches. The intermediate is proposed to be the disulfate ion S(2)O(7)(2-), which hydrolyzes into H(+) and either SO(4)(2-) or HSO(4)(2-) with a half-life of about 52 seconds at 25 degrees C.     

深圳市宝安区酸雨成分及相关分析

在深圳宝安区黄麻布收集了2006年5-12月的52次降雨水样,测定了水样中的F^-、Cl^-、NO3^-、 SO4^2-、H^＋、NH4^＋、Na^＋、K^＋、Mg^2＋、Ca^2＋的离子浓度,结果显示,宝安区酸雨较为严重,加权平均pH值为4.72;每月降雨量与pH值成负相关关系,一般雨季pH值低,旱季pH值高,但在异常的极端气候条件下,如台风对pH值的变化有很大的影响;宝安区的酸雨有由过去的硫酸型酸雨向硝酸型酸雨转变的趋势;宝安区靠近海洋,水样中富含Cl^-和Na^＋,海洋源对雨水中Cl^-和Mg^2＋的贡献较高,有时达到100%,对K^＋为10%左右,对Ca^2＋和SO4^2-几乎没有贡献,仅为1%-4%;在旱季时碱性离子的缓冲作用强,而雨季较弱;通过分析当地空气中的SO2和水样中的SO4^2-、NO2和NO3^-之间的关系发现NO2和NO3^-之间相关性较好,NO3^-主要来源于当地机动车辆尾气中的NO2;而SO2和SO4^2-相关性相对较差,SO4^2-除本地的污染外可能来源于龙岗区和南山区等周边地区传输的污染气体SO2。     

红寺堡开发区地下水水化学特征及水质评价

[目的]为查明宁夏红寺堡开发区地下水的水化学特征及水质现状,为地下水的合理开发利用提供依据。[方法]对研究区15个水样点的水化学指标进行统计分析,较全面地研究了地下水的水化学特征,并运用模糊数学法进行了地下水水质评价。[结果]研究区个别水样点的水化学指标满足生活饮用水卫生标准。地下水中色度、pH、H2SiO3的含量相对较稳定,而SO42-、CO32-、NH4＋-N和NO2--N的含量在空间存在较强的变异性。TDS总的变化趋势为自中部向东西两侧有增大的趋势,地下水化学类型以HCO3.Cl-Na、SO4.Cl-Na.Mg.Ca及SO4.Cl-Na.Mg型水为主。[结论]地下水水质总体不容乐观,在海子塘及甜水河脑附近,水质较好,适合当地居民饮用,其余地区水质较差,可做工业和农业用水。     

模拟酸沉降下南方两种森林土壤对SO42-及NO3-的吸附

通过 3种模拟酸沉降溶液对福建和贵阳两种森林土壤样品的连续浸泡试验 ,研究了土壤对酸沉降中 SO42 -和 NO3-的吸附 ,以及盐基离子输入对这种吸附的影响 .结果表明 ,2种土壤对 SO42 -均有一定的吸附能力 ,但福建土壤的吸附量比贵阳土壤大 .土壤对 SO42 - 的吸附与酸沉降中 SO42 - 浓度及土壤水溶性 SO42 - 含量有关 ,但高浓度的盐基离子输入会降低 SO42 -的吸附量 .土壤对 NO3-的吸附主要发生在表土中 ,且比 SO42 -的吸附量低 ,但比预料的要高     

Precipitate formation in the strontium-phosphate system

Study of the precipitation process in the aqueous Sr(OH)(2)-H(3)PO(4) system, in order to elucidate the phase transformations and the nature of the final solid phases, shows that over much of the range of compositions studied the initial precipitate is poorly crystalline; the x-ray pattern resembles that of strontium hydroxyapatite but has a strontium: phosphorus molar ratio close to 1.3. Within 1 hour the initial precipitate changes to a stable crystalline phase (or phases), with corresponding change, either up or down, in the strontium: phosphorus ratio. At high ratios of Sr(OH)(2) to H(2)PO(4) the initial precipitate is Sr(3)(PO(4))(2)-4H(2)O, which then converts to a phase having the x-ray diffraction pattern of strontium hydroxyapatite, but having a strontium: phosphorus ratio that depends somewhat on the initial ratio of Sr(OH)(2) to H(3)PO(4) used in the precipitation.     

中国七大区降水化学特性的空间差异及成因

选取中国七大区的33个省及城市20世纪90年代降水监测资料,通过对比分析,对中国七大区的降水化学特性、空间差异及成因进行了初步研究.结果表明,七大区降水中离子组成基本一致,但是主要离子含量差别较大;降水酸性也表现出明显的差异,总体表现为北方偏碱性,南方偏酸性,并且自东北向华南呈增强趋势;20世纪90年代中国大气硫污染突出,东北、西北地区SO42-及Ca2+含量是其他地区的2倍以上,并且北方降水中NH4+浓度较高,因而针对不同地区的降水化学特性,应采取不同的污染防治措施.     

Effects of Nitrogen Fertilizer with Nitrification Inhibitor DMPP (3,4-Dimethylpyrazole phosphate) on Nitrate Accumulation and Quality of Cabbage (Brassica campastris L.ssp.pekinesis)

To assess the effects of N fertilizer ammonium sulphate nitrate [(NH4)2SO4 plus NH4NO3;ASN] with the new nitrification inhibitor (NI) 3, 4-dimethylpyrazole phosphate (DMPP)(ASN+DMPP) on yield, nitrate accumulation, and quality of cabbage (Brassica campastrisL. ssp. pekinesis), two field trials were carried out under various soil-climatic conditions in Jinhua City and Xinchang County, Zhejiang Province of China in 2002.Results showed that DMPP could increase the mean yield by + 2.0 t ha-1 in Jinhua, +5.5 t ha-1 in Xinchang, decrease NO3--N content by -9.4% in Jinhua, -7.3% in Xinchang and improve nutritional quality by increasing vitamin C (VC), soluble sugar, K, Fe, Zn contents significantly.     

基于MaxEnt模型预测薄壳山核桃在中国的种植区

  目的  预测当前和未来中国适宜种植薄壳山核桃Carya illinoinensis的地区,对薄壳山核桃的引种栽培提供参考。  方法  基于北美薄壳山核桃栽培区的分布数据和世界环境气候数据,利用MaxEnt模型和ArcGIS预测薄壳山核桃当前以及未来不同气候情景下在中国的适生区范围。  结果  ①训练集和检验集的AUC值分别为0.987和0.985,表明预测结果精度高。②刀切法检验结果和贡献率结果表明:年均气温、最暖季平均气温、年降水量、最干月降水量、最干季平均气温、昼夜温差月均值和气温的季节性是薄壳山核桃生长的关键气候变量。③预测薄壳山核桃当前在中国的适生区主要集中在中东部省份,包括江西、湖南、湖北、安徽、浙江、江苏和河南;在未来碳排放增强的气候情景下,薄壳山核桃在中国中东部省份的潜在高适生区的面积大幅增加,适生范围有向北移动的趋势,少量延伸到了辽宁东部和吉林南部。  结论  利用MaxEnt模型预测的薄壳山核桃适生区主要集中在中国的中东部省份;随着未来气温的升高,薄壳山核桃的潜在高适生区在中国相应的中东部地区内扩张。图3表3参36