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81.
The changing chemical composition of cloud water and precipitation in the Western Sudety Mountains are discussed against the background of air-pollution changes in the Black Triangle since the 1980s until September 2004. A marked reduction of sulphur dioxide emissions between the early 1990's and the present (from almost 2 million tons to around 0.2 million tons) has been observed, with a substantial decline of sulphate and hydrogen concentration in cloud water (SO42− from more than 200 to around 70 μmol l− 1; H+ from 150 to 50 μmol l− 1) and precipitation (SO42− from around 80 to 20–30 μmol l− 1; H+ from around 60 to 10–15 μmol l− 1) samples. At some sites, where fog/cloud becomes the major source of pollutants, deposition hot spots are still observed where, for example, nitrogen deposition can exceed 20 times the relevant critical load. The results show that monitoring of cloud water chemistry can be a sensitive indicator of pollutant emissions. 相似文献
82.
1993—2006年中国区域酸雨变化特征及成因分析 总被引:28,自引:0,他引:28
中国气象局酸雨站网始建于1989年,最初仅有22个。1993—2005年,一直维持在85至88个,经2006和2007年两次扩建达到294个站。考虑到资料的连续性,本文是以80多个酸雨观测站有系统观测以来(即近14年)的酸雨观测资料为基础,经过客观统计分析,得出中国酸雨的时空变化特征。总的来说,中国酸雨区主体位于长江以南的广大地区,北方也存在小范围的酸雨区。从全国来看,酸雨发生范围总体上呈扩大趋势,北方酸雨发生范围扩大明显,南方基本保持不变;而且,酸雨污染重灾区由西南逐步转移至华中和华南中部。就酸雨强度而言,1993—1998年是最强阶段,1999—2002年强度有所降低,2003—2006年酸雨强度重又持续加强,到2006年已达到1993—1998年的平均水平;另一个显著特点是北方酸雨强度加强非常明显。对于中国区域降水酸度变化的成因,本文利用中国SO2排放量的变化和大气成分本底站降水化学的监测资料进行了分析和阐述。 相似文献
83.
84.
Near Eagle Plains, northern Yukon, Canada, acidic Ca-Fe-Mg sulfate waters are discharging year-long from disturbed permafrosted sandstone bedrock overlying pyritiferous black shales. These acidic waters are precipitating gypsum with minor amounts of jarosite-K (Na), schwertmannite and hematite. This mineral assemblage is similar to that observed at Meridiani Planum (and other location on Mars), making this site a valuable analogue for low-temperature sulfate geochemistry and mineral formation on Mars. Stable O-S isotope analysis of the acidic waters near Eagle Plains revealed that the oxygen in the dissolved sulfate is mostly derived from water (ca. 70%), suggesting that the sulfide oxidation process could be in part biomediated (i.e., accelerated by acidophilic Fe-oxidizing bacteria). However, unlike the dissolved sulfate in the waters, the formation of the Ca-Fe-SO4 minerals appears to be purely abiotic. The stable O-S isotope composition of the sulfate minerals is well within the predicted equilibrium range at low temperature, suggesting that they formed through physico-chemical processes (i.e., evaporation or freezing). Low-temperature geochemical modeling with FREZCHEM and PHREEQC suggests that the mineral assemblage at Eagle Plains precipitated mainly through the freezing of Ca-Fe-Mg-SO4 acidic waters, rather than through evaporation during the dry summer season, although the latter is still possible. This suggests that the sulfate mineral assemblage observed on Mars could have also formed under a periglacial-type climate. Considering that the active layer in the zone affected by acid drainage does not freeze-over during winter, the residual talik offers a localized niche environment to support acidophilic microorganisms. Overall, the fact that acid drainage is presently active near Eagle Plains allows the direct observation of the low-temperature geochemical processes responsible for generating acid drainage conditions and precipitation of gypsum, schwertmannite, jarosite-K, jarosite-Na, goethite and hematite. 相似文献
85.
86.
Shuping Bi 《Environmental Geology》2001,40(3):300-304
The aim of this paper was to analyze the processing and transport of aluminum speciation through the terrestrial and aquatic
ecosystems of the Chesapeake Bay landscape. Stream waters were sampled in 14 different streams from the Susquehanna River
watershed to the upper reach of Chesapeake Bay. The basic water quality data were documented and Al speciation was evaluated
by modified MINEQL computer model. It was found that the increase in acidity in some of the stream waters near New York were
closely linked with a marked decline in basic cation concentrations. In these areas, the sum of the toxic forms of Al3+ plus AlOH2+ and Al(OH)2
+ concentrations exceeds the critical level of 5 μmol l–1. A potential threat from aluminum may occur.
Received: 3 January 2000 · Accepted: 21 March 2000 相似文献
87.
胶州湾养殖海区沉积物中酸可挥发性硫的研究 总被引:19,自引:1,他引:19
沉积物中酸可挥发性硫化物(AVS)的含量对控制重金属在沉积物/间隙水中的分配和重金属的生物可利用性方面有重要意义,也是海洋养殖业的重要指标之一,研究改正目前《海洋监测规范》中沉积物酸可挥发硫化物的测定方法基础上,建立了一套简单易行的仪器装置和分析程序,讨论了N2流量、反应时间、酸强度、硫总量4个方面对测定结果的影响,给出了胶州湾海区沉积物中AVS的定量数据,表明胶州湾养殖海区沉积物中AVS的含量显著高于非养殖海区和其它海湾沉积物中AVS的定量数据,表明胶州湾养殖海区沉积物中AVS的含量显著高于非养殖海区和其它海湾沉积物中AVS的含量,探讨了应用AVS归一化沉积物中二价有毒金属评价其化学活性和生物可用性的可能性。 相似文献
88.
介绍了晶安高科污染源的来源、采取的措施及综合治理、利用方法.使废水指标由PH11~12;SS<1000mg/l;CODcr≤200mg/l;氨氮≤200mg/l降到PH6~9;SS<70mg/l;CODcr≤100mg/l;氨氮≤15mg/l;酸雾指标由HCl500~800mg/m3达到小于25~40mg/m3;炉窑烟气由林格曼黑度5,烟尘浓度2700~5191mg/Nm3降到林格曼黑度1,烟尘浓度小于200mg/Nm3;硅渣可生产复合絮凝剂和白炭黑,不仅可改善环境影响,而且可回收盐酸和利用废资源,可给企业带来经济效益. 相似文献
89.
In order to assess the magnitude and impact at affected mine sites of acid rock drainage (ARD), fixed-frequency sampling is often employed. This often involves manual sampling, at regular time intervals, of water and solids. It is felt that such sampling does not adequately describe the system evolution. Continuous monitoring offers a viable alternative in that it can better follow the seasonal fluctuations and high-frequency variations that characterize ARD. This paper evaluates existing continuous monitoring technology. 相似文献
90.
本文对中国33个站、日本29个站及美国9个站的降水化学资料进行了分析比较.结果表明,中、日、美三国的降水化学特性有很大不同.三国都有酸雨,但以美国的pH平均值最低.雨水中离子总浓度以中国为最高,其中SO_4~=,NH_4~+和Ca~(++)的浓度特别高.日本雨水中Cl~-和Na~+的浓度很高.NO_3~-在美国雨水中最高.从雨水中离子结构组成和几种重要参量的比值分析表明,中国雨水中的离子浓度受陆地源影响很大,而影响日本雨水中离子浓度最大因素是海洋.在美国以工业交通污染的影响相对最大.文中还对中、日两国不同地区的降水化学特性进行了分析和讨论. 相似文献