城市化进程中长江经济带长江干流水化学演变特征及影响因素

快速的城市化过程对城市周边水体水化学组成特征产生了诸多影响.为揭示长江经济带城市群发展对长江水化学特征的影响,于2020年10—11月沿长江干流,采集了四川宜宾至上海145个河流水样,并对比了历史水化学数据.同时,运用数理统计、离子比值法等方法探究了长江经济带平水期水化学特征.结果表明：长江河水的主要水化学类型为HCO₃·SO₄-Ca型,主要受流域内分布的碳酸盐岩等岩石风化作用控制;河水中阳离子以Ca²⁺为主,阴离子以HCO₃^-为主,Cl^-浓度沿径流方向升高,Ca²⁺和Mg²⁺浓度沿径流方向先升高后降低,SO₄^2-浓度沿径流方向逐渐上升,HCO₃^-浓度沿径流方向降低;城市化进程中,由于人类活动和工业活动加剧,除HCO₃^-外,Ca²⁺、Mg²⁺     

Long term changes in atmospheric N and S throughfall deposition and effects on soil solution chemistry in a Scots pine forest in the Netherlands

In a Scots pine forest the throughfall deposition and the chemical composition of the soil solution was monitored since 1984. (Inter)national legislation measures led to a reduction of the deposition of nitrogen and sulphur. The deposition of sulphur has decreased by approximately 65%. The total mineral-nitrogen deposition has decreased by ca. 25%, which is mainly due to a reduction in ammonium-N deposition (−40%), since nitrate-N deposition has increased (+50%). The nitrogen concentration in the upper mineral soil solution at 10 cm depth has decreased, leading to an improved nutritional balance, which may result in improved tree vitality. In the drainage water at 90 cm depth the fluxes of NO₃⁻ and SO₄²⁻ have decreased, resulting in a reduced leeching of accompanying base cations, thus preserving nutrients in the ecosystem. It may take still several years, however, before this will meet the prerequisite of a sustainable ecosystem.     

Using Lichen Chemistry to Assess Airborne Tungsten and Cobalt in Fallon, Nevada

This paper describes the use of lichen chemistry to assess airborne tungsten and cobalt in Fallon, Nevada, where a cluster of childhood leukemia has been on going since 1997. Lichens and their rock substrates were collected from Rattlesnake Hill within Fallon as well as from four different rock outcrops located north, east, south, and west of Fallon and at least 20 km away from the town center. In the lichens themselves, W and Co are significantly higher within Fallon than in the combined control site outside of Fallon. In the rock substrates of the lichens, no differences exist in W and Co. The W and Co differences in lichens cannot be attributed to substrate geochemistry. Fallon is distinctive in west central Nevada for high airborne W and Co, and given its cluster of childhood leukemia, it stands to reason that additional biomedical research is in order to test directly the leukogenicity of combined airborne W and Co.     

深圳市龙华区PM2.5污染与减排过程模拟分析

通过分析深圳市龙华区2018年大气环境承载力发现,NO2和PM10的实际大气环境承载量已经降到了理想大气环境容量范围内,而PM2.5的实际大气环境承载量则已超过理想大气环境容量近1 000 t,说明PM2.5仍是龙华区大气污染防治的重点工作,利用科学手段精准、有效地指导PM2.5减排工作十分重要.基于相关监测数据,结合...     

合流制排水系统溢流污染就地调蓄处理控制技术研究

在对高效混合絮凝斜板沉淀工艺进行现场中试的基础上,将化学强化处理工艺与调蓄池相结合,针对上海市某合流制排水系统,进行调蓄/沉淀池的概念设计,提出主要设计参数,利用计算流体力学(CFD)模型对调蓄/沉淀池进行优化设计.试验和模拟结果表明,调蓄/沉淀池与单纯的调蓄池相比具有更好的溢流污染控制效果和效益/造价比.     

成都市2002年1月2日至4日浓雾天气雾的化学组成

为了查明雾天雾的化学学组成，2002年1月2日至1月4日，利用人为结露的方法采集了雾天的雾，并洲定了阴离子组成。与室内采集的凝结露水的研究进行比较，大雾天的雾中含有极高的硝酸粮，这是因为雾的形成过程中亚硝酸根进一步氧化为硝酸根的原因。     

略论我国的环境化学研究进展

本文概略论述了２０多年来我国环境化学的研究状况，就环境污染分析化学、环境污染化学、环境污染控制化学今后的研究趋势和重点研究方向提出了自己的看法。     

IMPACT OF SURFACE COAL MINING ON THREE OHIO WATERSHEDS –PHYSICAL CONDITIONS AND GROUND-WATER HYDROLOGY1

ABSTRACT: A study was conducted over a six-year period in East-Central Ohio to determine the effects of surface mining and reclamation on physical watershed conditions and on ground-water hydrology in three ground-water zones in three small experimental watersheds. Mining disturbances in watersheds adjacent to the experimental sites affected ground-water levels in the undisturbed experimental watersheds prior to actual mining in the experimental sites. New subsurface flow paths, with different characteristics, formed during mining and reclamation. At all three sites mining dewatered the saturated zone above the underclay of the mined coal seam. Mining and reclamation affected ground-water levels below the mined coal seam in the middle and lower zones within at least two sites. Ground-water level recovery in the mined upper saturated zone was slow and irregular both temporally and spatially after reclamation. Hydraulic conductivities of postmining (Phase 3) spoil were generally greater than those of Phase 1 bedrock, but wide spatial variability was observed. Modelers need to be aware of the complexities of new flow paths and physical characteristics of subsurface flow media that are introduced by mining and reclamation, including destruction of the upper-zone clay.     

Regional characteristics of land use in Northeast and Southern Blue Ridge Province: Associations with acid rain effects on surface-water chemistry

The Direct/Delayed Response Project (DDRP) is one of several studies being conducted by the United States Environmental Protection Agency to assess risk to surface waters from acidic deposition in the eastern United States. In one phase of DDRP, land use, wetland, and forest cover data were collected for statistical samples of 145 Northeast lake and 35 Southern Blue Ridge Province stream watersheds in the United States. Land-use and other data then were extrapolated from individual to target watershed populations. Project statistical design allows summarization of results for various subsets of the target population. This article discusses results and implications of the land-use and land-cover characterization for both regions. Forest cover was the primary land use in both regions. In the Northeast, developed (agriculture and urban) land was positively associated with surface-water chemistry values for acid neutralizing capacity, Ca plus Mg, pH, and sulfate in the Pocono/Catskill subregion. Extensive wetlands and beaver activity occur in parts of the Northeast region, whereas topography limits wetland and riparian development in the Southern Blue Ridge Province. Northeast soils have low sulfate adsorption capacity, most watersheds are near sulfur steady state, and lake sulfate concentrations are controlled principally by levels of sulfur deposition. Net annual sulfur retention in Northeast watersheds is positively correlated with occurrence of wetlands and beaver impoundments. In contrast, most Southern Blue Ridge Province soils have high sulfate adsorption capacities, resulting in high net watershed sulfur retention. At the present time, stream sulfate concentrations and percent sulfur retention are controlled principally by soil chemical properties related to adsorption rather than atmospheric deposition and land use. The information in this document has been funded wholly by the United States Environmental Protection Agency. It has been subjected to the agency's peer and administrative review, and it has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.