温州红壤的酸沉降临界负荷研究

本文简要介绍了以碱总量守恒为基础建立的兼能描述钙质与非钙质土壤长期酸化过程的动态模型（ＬＴＳＡＭ），并利用该模型讨论了温州红壤的酸沉降临界负荷。结果表明，以硫沉降即酸沉降的硫沉降非酸沉降两观点分别来确定红壤的临界负荷，其值依次为３．９１与１．８４ｇ·ｍ＾－２·ａ＾－１，后者仅是前者的４７％，差异显著应加以区别。     

酸沉降对森林植物影响过程和机理

文章丰要包括如下几方而的内容：（1）概述了酸沉降作用下森林衰退的状况及其相关工作的开展情况；（2）总结了酸沉降对森林植物的影响过程和机理；（3）阐述了酸沉降对森林植物影响研究的模型和临界酸负荷值的确定；（4）探讨了存在的问题和未来值得研究的方向。指山未来的研究方向主要是：酸沉降对森林生态系统的影响机理和森林生态系统对酸沉降的反馈机制；酸沉降对非优势种、稀有种及低等植物的影响；酸沉降与其它环境因子对森林植物的共同影响；酸沉降的监控和预测，建立适合我斟实际情况的研究模型；将常规分析手段和分子生物学技术相结合，加强抗性植物和指示植物的筛选工作；加强受损森林植被的恢复和重建工作；开展酸沉降对森林植被的格局动态及森林演替动态变化研究。     

酸沉降下加速土壤酸化的影响因素

酸沉降对土壤和水域的酸化影响是土壤环境化学研究前沿的热点问题之一。酸沉降的化学组成对酸性土壤的进一步酸化起着催化剂的作用。在酸雨影响下,SO42-、NO-3、有机阴离子是加速土壤酸化和盐基淋溶损失的主要阴离子,外源H+的进入会加速铝离子水解。自然因素与人为因素导致土壤酸化的实际酸化速率差异表明:HCO3-、RCOO-在土壤剖面中的淋失状况可反映自然土壤的酸化速率,而SO42-和NO-3淋溶产生的质子负荷揭示土壤受人为因素影响的酸化速率。通过计算酸沉降的主要化学成分进入土壤前后的质子负荷平衡,与酸中和容量(ANC)相结合,反映酸沉降加速土壤酸化的进程。     

南宁市老虎岭水库酸化预测模型

本文介绍了用ILWAS模型模拟的三种不同酸沉降负荷下南宁老虎岭水库酸化的趋势以及应用诺漠图方法建立的适用于污染控制决策的酸沉降负荷与地表水体酸化速率关系模型。     

模拟酸雨对峨眉山冷杉林土壤特性的研究

本文采用模拟酸雨方法，考察了峨眉山不同区域冷杉生长正常区和受害区的土壤样品，在酸沉降影响下，土壤特性所发生的改变，测定了土壤酸碱度及主要元素含量。同时以未受到酸沉降侵蚀的贡嗄山土样作为对照点，探讨由酸沉降所造成的土壤酸化，进而引起土壤特性改变与冷杉生长间的关系。     

宁夏燃煤电厂周围降水降尘中硫氮沉降特征研究

燃煤电厂是SO_2和NOx的主要排放源之一。本世纪初以来,随着煤炭等行业的快速发展,中国西北地区大气酸沉降速率加快。以宁东能源化工基地3个燃煤电厂为监测点,初步探讨了2019年1—6月电厂周围降水降尘S、N组成特征。结果表明:研究区SO_4~(2-)月沉降量、NO_3~-月沉降量、NH_4~+月沉降量、无机N月沉降量、SO_4~(2-)/NO_3~-和NO_3~-/NH_4~+均存在较大变异,其平均值分别为(2.51±0.07)、(1.17±0.05)、(0.23±0.01)、(1.40±0.05) kg·hm~(-2)·month-1、(3.82±0.26)和(5.34±0.21);马莲台电厂和灵武电厂具有较高的SO_4~(2-)月平均沉降量、NH_4~+月平均沉降量和SO_4~(2-)/NO_3~-,鸳鸯湖电厂具有较高的NO_3~-月平均沉降量、无机N月平均沉降量和NO_3~-/NH_4~+;除SO_4~(2-)/NO_3~-外,5月各指标的测定值较高,2月各指标的测定值较低;除SO_4~(2-)月平均沉降量外,各指标在取样距离间差异较小。以上结果意味着,SO_4~(2-)是研究区降水降尘中主要的酸沉降形式、NO_3~-是其主要的N沉降形式,体现了以燃煤电厂为主导的工业源排放特点;研究区SO_4~(2-)沉降量与全国水平相当,但低于区域S沉降临界负荷。N沉降量高于中国西北地区平均值,且超过了区域可接受的沉降量;鉴于本研究收集的大气沉降为湿沉降加部分干沉降,故可能低估了研究区S、N总沉降量。考虑到酸沉降的时间累积性,宁夏燃煤电厂S、N限排工作依然十分必要。     

土壤污染物来源及前沿问题

人类活动对土壤系统的影响日趋严重。土壤污染物主要来自污染的大气沉降，废水和污水灌溉，工业废渣和城市垃圾，以及农药施用等。土壤污染对环境和人体健康造成极大的危害。文章通过计算得出了大气汞沉降和酸沉降在中国的累积沉降量，并通过调查分析中国各项污染物来源的最新资料，详细论述了各主要污染因素对土壤系统的影响。文章阐述了污染物在土壤系统中主要的物理化学行为，主要包括污染物在土壤生态系统中的吸附、迁移和扩散、酸沉降对土壤系统的影响等三个方面。最后回顾了该领域的研究现状和主要的前沿问题，并对进一步的深入研究提出了建议。     

中国大气酸沉降与土壤酸化问题

我国对大气酸沉降的研究起自７０年代末．以酸雨研究占主导地位。我国酸雨现象区域性、发展性强，在地理上以南方酸性土壤地区为主，在成分上以硫酸盐型酸雨为主；无论是酸度还是频率，酸雨都是极严重的生态环境问题。酸沉降已对农、林生态系统生产产生了严重的破坏效应，但其累积性的环境化学反馈却未引起人们的足够重视。我国酸雨地区以强酸性富铝土壤为主，对大气酸沉降有较大的敏感性。应用β指标还表明，酸沉降可使南方主要土壤因酸化而在３０—６０年内降低ｐＨ一个单位。近年来对酸沉降诱发的土壤酸化研究以模拟降水的土柱试验为主，从ｐＨ下降、盐基淋出、Ａｌ及重金属移动等方面来提示出酸沉降可能对土壤产生的化学影响。但作为过程化学研究，其案例监测研究的报道尚很少。对于南方严重的酸雨现象，应加强实地动态监测和过程分析，注重Ａｌ化学及其对环境的反馈，将酸沉降对生态系统的破坏提高到生态毒理机制上。     

大气颗粒物缓冲能力参数化

本文探讨了大气颗粒物对酸的缓冲能力的参数化方法,提出了具有明确参数意义的缓冲方程,并用滴定实验进行了检验.结果表明,指数加线性形式的参数化方程对于描述大气颗粒物的缓冲能力及其时变关系是可以接受的.本文还初步讨论了大气颗粒物参数化方法的应用,表明这种参数化方法在数值模拟酸沉降下洗脱过程中大气颗粒物的缓冲作用可能比较合适.     

GIS支持下密云水库石匣小流域非点源污染

利用GIS建立石匣小流域非点源污染信息的数据库,分别以SCS方程、USLE方程和污染物迁移为核心,初步建立非点源污染负荷模型。模型的界面设计体现了VB面向对象的程序设计,直接在WINDOWS环境下运行。采用实测资料对SCS法进行修正。USLE方程计算,取得较为理想的结果。     

Tolerance of calluna vulgaris and peatland plant communities to sulphuric acid deposition

Critical loads offer a unique way of evaluating impacts of acid deposition by quantifying environmental sensitivity. The critical loads of acidity for UK peat soils have been based upon an arbitrary reduction in pH of 0.2 units. This chemical shift needs to be better related to adverse effects on sensitive biological receptors. It is known that effective precipitation pH equates closely to soil solution pH, and the latter is directly linkable to biotic effects of pH change. On continuation of a long-term experiment assessing impacts of simulated acid rain on peat microcosms in a realistic outdoor environment, Calluna vulgaris continued to flourish at acid deposition loads well above the existing critical load. Calluna plants were harvested and analysed, and acid deposition treatments to the microcosms continued to allow natural vegetation to regenerate. A diverse mixture of moorland plants and bryophytes established at acidity treatments well above the existing critical load, and only a very high acid load resulted in no natural regeneration. A critical effective rain pH value of 3.6 is suggested as a basis for setting critical loads. At this pH, Calluna grows well, and a healthy diverse vegetation community re-establishes when harvested. It is suggested that the peat critical load should be set at the acid load that, at any specific site, would result in a mean effective precipitation pH of 3.6.     

Obligatory barrier crossing and adaptive fuel management in migratory birds: the case of the Atlantic crossing in Northern Wheatears (<Emphasis Type="Italic">Oenanthe oenanthe</Emphasis>)

Behaviour on migration was often suggested to be selected for time-minimising strategies. Current optimality models predict that optimal fuel loads at departure from stopover sites should increase with increasing fuel deposition rates. We modified such models for the special case of the east Atlantic crossing of the Northern Wheatear (Oenanthe oenanthe). From optimality theory, we predict that optimal time-minimising behaviour in front of such a barrier should result in a positive correlation between fuel deposition rates and departure fuel loads only above a certain threshold, which is the minimum fuel load (f _min) required for the barrier crossing. Using a robust range equation, we calculated the minimum fuel loads for different barrier crossings and predict that time-minimising wheatears should deposit a minimum of 24% fuel in relation to lean body mass (m ₀ ) for the sea crossing between Iceland and Scotland. Fuel loads of departing birds in autumn in Iceland reached this value only marginally but showed positive correlation between fuel deposition rate (FDR) and departure fuel load (DFL). Birds at Fair Isle (Scotland) in spring, which were heading towards Iceland or Greenland, were significantly heavier and even showed signs of overloading with fuel loads up to 50% of lean body mass. Departure decisions of Icelandic birds correlated significantly with favourable wind situations when assuming a migration direction towards Spain; however, the low departure fuel loads contradict a direct non-stop flight.     

A Critical Appraisal of Field Evidence From A Regional Survey for Acid Deposition Effects On Scottish Moorland Podzols

Samples have been collected from major horizons of 34 podzol profiles distributed throughout Scotland, all developed from granite or granitic tills and under Calluna moorland. the pH in water and calcium chloride pastes, exchangeable cations and cation exchange capacity, and extractable aluminium of the soils collected have been measured, and the results studied in relation to reported atmospheric deposition of H⁺, non-marine sulphur and nitrate. for all horizons, significant positive correlations were found between soil pH and rainfall mean pH, as might be expected when the critical load of H⁺ deposition is exceeded. Acidifying pollutant deposition also apparently increased soil extractable aluminium concentrations in the B and C horizons. However, exchangeable base cation concentrations tended to increase, rather than decrease, with increasing precipitation acidity. This effect was attributed to increases in biogeochemical cycling of base cations, increases in leaching inputs of base cations from overlying A/E horizon soils, and increases in the inputs of base cations leached from upslope. the results suggest that the simple steady state mass approach to the quantification of critical loads, as often applied, may be an oversimplification.     

A Critical Appraisal of Field Evidence From A Regional Survey for Acid Deposition Effects On Scottish Moorland Podzols

Samples have been collected from major horizons of 34 podzol profiles distributed throughout Scotland, all developed from granite or granitic tills and under Calluna moorland. the pH in water and calcium chloride pastes, exchangeable cations and cation exchange capacity, and extractable aluminium of the soils collected have been measured, and the results studied in relation to reported atmospheric deposition of H⁺, non-marine sulphur and nitrate. for all horizons, significant positive correlations were found between soil pH and rainfall mean pH, as might be expected when the critical load of H⁺ deposition is exceeded. Acidifying pollutant deposition also apparently increased soil extractable aluminium concentrations in the B and C horizons. However, exchangeable base cation concentrations tended to increase, rather than decrease, with increasing precipitation acidity. This effect was attributed to increases in biogeochemical cycling of base cations, increases in leaching inputs of base cations from overlying A/E horizon soils, and increases in the inputs of base cations leached from upslope. the results suggest that the simple steady state mass approach to the quantification of critical loads, as often applied, may be an oversimplification.     

Should I stay or should I go? Testing optimality models of stopover decisions in migrating birds

Time-minimizing migrants should leave a stopover site if the instantaneous speed of migration drops to the average speed of migration in the environment. This argument has been used in two different ways: either there is local variation in the fuel deposition rate and a fixed expected speed or there is global variation in the fuel deposition rate, i.e. locally experienced variation represents global variation along the route. The first case leads to a far steeper relationship between departure load and fuel deposition rate than the second case. So far, data on departure loads have mainly been analysed within the concept of local variation of the fuel deposition rate and the result that the observed slopes are much lower than predicted has been explained by changes in the expected speed along the route or by individual differences in the expected speed. We show here that the observed relationships generally fall close to the predictions for global variation. We propose that migrants use a behavioural rule which projects the current experience into the future and therefore interprets local variation as global variation. Received: 3 April 1999 / Received in revised form: 22 April 1999 / Accepted: 26 April 1999     

Chemistry of atmospheric dust and critical load assessment in Delhi region (India)

This is the first study in the Delhi region that assesses the critical load capacity of soil systems with respect to the atmospheric deposition and air quality, from July to October in 2012. Trend analysis of NO₂ and SO₂ in Delhi, using the Central Pollution Control Board (CPCB) data, showed interesting patterns matching with the trends in vehicular load in the city. This was followed by the calculation of the critical load of atmospheric acidity for sulphur and nitrogen in order to check the vulnerability of the soil systems in Delhi. Here, the steady state mass balance approach was majorly applied and the study conducted in the Agra region was taken as reference. The calculated values of critical loads of sulphur (225–275?eq/ha/yr) and nitrogen (298–303?eq/ha/yr), for the soil system in Delhi, were calculated with respect to three plant species, namely Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S)?=?26.40?eq/ha/yr) and nitrogen (PL(N)?=?36.51?eq/ha/yr) were found to be much lower than their respective critical loads. From the results, it can be concluded that the present loads of atmospheric acidic deposition in Delhi region do not pose any danger of acidification of soil system because it is countered by buffering capacity of soil generated dust. However, considering the pace at which the city is growing, it is likely that in coming decades, the present load will increase and thus the values evaluated in this study are likely to serve as an important reference for future assessment of the pollution scenario in the city.     

水体沉积物中酸挥发性硫化物垂直分布模型的参数计算及相关分析

应用试验及文献数据计算了东湖沉积物中酸挥发性硫化物（AVS）垂直分布模型的参数值，并进行了参数的相关性分析。结果表明，AVS含量是沉积物中有机质的分解、AVS的沉淀、溶解及氧化共同作用的结果，较好地解释了东湖三个污染状况不同站点ABS垂直分布的差异，从而为应用ABS判断沉积物重金属生物有效性提供了科学依据。     

Nitrogen critical loads for alpine vegetation and terrestrial ecosystem response: are we there yet?

Increases in the deposition of anthropogenic nitrogen (N) have been linked to several terrestrial ecological changes, including soil biogeochemistry, plant stress susceptibility, and community diversity. Recognizing the need to identify sensitive indicators of biotic response to N deposition, we empirically estimated the N critical load for changes in alpine plant community composition and compared this with the estimated critical load for soil indicators of ecological change. We also measured the degree to which alpine vegetation may serve as a sink for anthropogenic N and how much plant sequestration is related to changes in species composition. We addressed these research goals by adding 20, 40, or 60 kg N x ha(-1) x yr(-1), along with an ambient control (6 kg N x ha(-1) x yr(-1) total deposition), to a species-rich alpine dry meadow for an eight-year period. Change in plant species composition associated with the treatments occurred within three years of the initiation of the experiment and were significant at all levels of N addition. Using individual species abundance changes and ordination scores, we estimated the N critical loads (total deposition) for (1) change in individual species to be 4 kg N x ha(-1) yr(-1) and (2) for overall community change to be 10 kg N x ha(-1) x yr(-1). In contrast, increases in NO3- leaching, soil solution inorganic NO3-, and net N nitrification occurred at levels above 20 kg N x ha(-1) x yr(-1). Increases in total aboveground biomass were modest and transient, occurring in only one of the three years measured. Vegetative uptake of N increased significantly, primarily as a result of increasing tissue N concentrations and biomass increases in subdominant species. Aboveground vegetative uptake of N accounted for <40% of the N added. The results of this experiment indicate that changes in vegetation composition will precede detectable changes in more traditionally used soil indicators of ecosystem responses to N deposition and that changes in species composition are probably ongoing in alpine dry meadows of the Front Range of the Colorado Rocky Mountains. Feedbacks to soil N cycling associated with changes in litter quality and species composition may result in only short-term increases in vegetation N pools.     

Hindcasting nitrogen deposition to determine an ecological critical load.

Using an estimated background nitrogen (N) deposition value of 0.5 kg N x ha(-1) x yr(-1) in 1900, and a 19-year record of measured values from Loch Vale (Colorado, USA; NADP site CO98), I reconstructed an N-deposition history using exponential equations that correlated well with EPA-reported NO(x) emissions from Colorado and from the sum of emissions of 11 western states. The mean wet N-deposition values for the period 1950-1964 was approximately 1.5 kg N x ha(-1) x yr(-1), corresponding to the reported time of alteration of diatom assemblages attributed to N deposition in alpine lakes in Rocky Mountain National Park (USA). This value becomes the critical load defining the threshold for ecological change from eutrophication. Thus if an N-deposition threshold for ecological change can be identified, and the date at which that threshold was crossed is known, hindcasting can derive the amount of atmospheric deposition at the time of change, at least for alpine lakes. Independent support for the technique and the deposition amount comes from experimental studies, ecosystem modeling, and paleolimnological records from northern Wyoming (USA).     

基于清单分析的农业非点源污染控制区划方法

进行农业非点源污染控制区划,识别出污染关键源区,可以提高非点源污染控制成效。通过清单分析定量核算农业非点源污染物(COD、TN、TP)排放量及排放浓度,并以非点源污染敏感性评价和污染类型划分为研究基础,探讨了农业非点源污染控制区划方法,提出了区划原则、分区方法和命名方法。该区划结果可以实现农业非点源污染的分级管理和分类控制。最后,以江苏省的64个县(市、区)作为基本单元(市辖区除外),采用该方法进行了农业非点源污染控制区划。