Deposition and Atmospheric Nitrogen Concentrations Trends in Cuba

The NO₂, nitrate and ammonia sampling in aerosols and rainfall was carried out at five stations located along the Cuban Island from 1986 to 1991. The sampling and chemical analysis were made mainly on the basis of methodologies recommended by WMO for above mentioned compounds at regional level. The total deposition of these compounds varies from 0.706 to 3.317 g m^-2 yr^-1. The wet deposition is about of 60%, so that the dry one is 40%. The amount of both depositions depends on our tropical rainy climate features. For some of these compounds the trend is increasing.     

Heterogeneous Atmospheric Nitrogen Deposition Effects Upon the Nitrate Concentration of Stream Waters in a Forested Mountain Area

Nitrogen compounds generated by anthropogenic combustion deposits in forest watersheds and induce nitrogen saturation of the area. Because excess nitrogen is derived from atmospheric deposition, this action is expected to uniformly affect a wide area of forest soils. Geographically, heterogeneous nitrate concentration of stream water within a small area has been attributed to the tree type, geological setting and tree cut. In this article, we hypothesized that the effect of the atmospheric nitrogen deposition in the forest watershed may vary within a small area, and that such variation is induced by the degree of air mass containing a high concentration of nitrogen deposition of combustion origin. We measured major ion concentrations, including nitrate, nitrite oxygen and nitrogen stable isotope of nitrate sampled at 24 water streams in the Chichibu region, which is 50?C100 km from the Tokyo metropolitan area. The nitrate concentration showed a wide range (25.6?C237 ??mol L^?1) within 300 km², which was explained sufficiently by the air mass advection path and its contact with the mountain??s surface. The nitrate concentration showed a significant positive correlation with chloride (r?=?0.73; p?<?0.001). As chloride originates outside of the Chichibu region, the positive correlation between two ions showed that the nitrate concentration of the stream water was affected by the nitrogen compound from the Tokyo Metropolitan area as a form of atmospheric deposition. Between the nitrate concentration and the stable isotope ratio of oxygen of nitrate, there was a positive correlation until nitrate concentration of 100 ??mol L^?1. When the nitrate is over 100 ??mol L^?1, ??¹⁸O shows a stable value of ca. 5.7??. This indicates that the nitrification proceeds when the nitrate concentration was low to middle, but the reaction slowed when the nitrate concentration became high. Oxygen stable isotope of nitrate along with a set of nitrate concentrations can be used as a good indicator of nitrogen saturation.     

Atmospheric Deposition of Acidifying Components to a Japanese Cedar Forest

One-year field measurements were conducted in a Japanese cedar (Cryptomeria japonica) forest, located in Gunma Prefecture, Japan. On the basis of the meteorological and atmospheric concentration data, the dry deposition of SO₂, HNO₃, NO₂ and HCl was estimated using the inferential method. The annual dry deposition of H⁺ was estimated at 721 eq ha^?1yr^?1, which was 40% larger than the measured annual wet deposition of H⁺ (514 eq ha^?1yr^?1). Therefore, dry deposition is an important pathway for the atmospheric input of H⁺ to the forest in the study site. The contribution of each gas to the dry deposition of H⁺ was as follows: SO₂, 25%; HNO₃, 32%; NO₂, 10%; and HCl, 33%. The extremely high contribution of HCl appeared to be caused by the high emission intensity of HCl due to waste incineration in the site region. The differences between estimated deposition and throughfall and stemflow measurements indicated that about 80% of the total deposition of H⁺ was taken up by the canopy.     

Atmospheric SO2 Pollution and Acidity of Rain in Changchun China

It is mainly SO₂ that bring about acid rain in China. Changchun City, which is located in Northeast China, is a typical city that is polluted by SO₂ from coal combustion in winter. In winter, the daily mean concentration of atmospheric SO₂ is about 0.10mg/m³ and about 5 times as high as in summer, and the daily highest concentration usually appears in daybreak and nightfall. The monitored lowest pH value of rainwater was 4.8 in spring and the range of pH value of rain/snow was 5.2–6.0 in winter, 4.8–5.8 in spring, 5.4–6.4 in summer, 5.6–6.4 in autumn, and the annual mean pH value of rainfalls was 5.8 (1999–2000). Because the alkaline aerosol from soil, meteorological conditions etc., is unfavorable to acid rain formation, even though high SO₂ emission intensity existed in winter, the acid rain did not appear obviously. The aerosol character, climate conditions in Northeast China are important factors for the acid rain formation, although SO₂ emission is the original cause.     

Rainfall Concentrations and Wet Atmospheric Deposition of Phosphorus and Other Constituents in Florida,U.S.A.

Concentrations of phosphorus (P) and other constituents inweekly composited rain samples and concurrently acquired rainfallvolumes, collected from September 1992 through October 1993, wereused to estimate volume-weighted concentrations and wetatmospheric deposition rates, and compared to estimates fromprevious studies. Since this study’s purpose was to estimateregionally representative concentrations and rates of wetatmospheric deposition, sampling locations were chosen to avoidsites characterized by substantial local resuspension orrecycling phenomena. Significant differences were found in the wet deposition rates of calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), hydrogen (H), and chloride (Cl) ions between sampling stationsin Florida. Consequently, statewide deposition rates and volume-weighted concentrations were estimated only for P, and fororthophosphate (PO₄), ammonium (NH₄), nitrate (NO₃) and sulfate (SO₄) ions that were not found to be spatially variable. Over the period of record, the mean rate of wet atmospheric P deposition across the state, and the mean rainfall P concentration, were found to be 25±>5 μg P M^-2 wk^-1 and 1.3±0.1 μg P L ^-1, respectively.     

Fog- and Rainwater Chemistry in the Tropical Seasonal Rain Forest of Xishuangbanna, Southwest China

Fogwater, fog drip and rainwater chemistry were examined at a tropical seasonal rain forest in Xishuangbanna, southwest China between November 2001 and October 2002. During the period of observation, 204 days with the occurrence of radiation fog were observed and the total duration of fog was 1949 h, of which 1618 h occurred in the dry season (November to April), accounting for 37.0% of the time during the season. The mean pH of fogwater, fog drip and rainwater were 6.78, 7.30, and 6.13, respectively. The ion with the highest concentration for fog- and rainwater was HCO₃ ^?, which amounted to 85.2 and 37.3 μeq l^?1, followed by Ca²⁺, Mg²⁺ and NH₄ ⁺. Concentrations of NO₃ ^?, HCO₃ ^?, NH₄ ⁺, Ca²⁺, and K⁺ in fogwater samples collected in the dry season were significantly greater when compared to those collected in the rainy season. It was found that the ionic concentrations in fog drip were higher than those in fogwater, except for NH₄ ⁺ and H⁺, which was attributed to the washout of the soil- and ash-oriented ions deposited on the leaves and the alkaline ionic emissions by the leaves, since biomass burns are very common in the region and nearby road was widening.     

Cd,Cu, Pb and Zn Concentrations in Atmospheric Wet Deposition at a Coastal Station in Western Europe

Water, Air, &; Soil Pollution - Bulk rainfalls were sampled during ten months in the Eastern Channel (Northern France). Chloride and sodium are the heavily loaded major ions in wet deposition,...     

Heavy Metal Concentrations,Partitioning, and Storage in Slovak Forest and Arable Soils Along a Deposition Gradient

Along a heavy metal deposition gradient, caused by a Cu smelter, heavy metal concentrations, partitioning, and storage in forest and arable soils were examined. We sampled organic and mineral soil horizons (0—50 cm) at ten pairs of forest and arable sites derived from the same parent material. A-horizons were extracted with a seven-step sequence; O- and subsoil horizons were digested with strong acids (HNO₃/HClO₄). We found high concentrations of Cd (up to 17.38 mg kg^—1 in the O horizons/up to 2.44 mg kg^—1 in the A horizons), Cu (8437/415), Pb (3343/126), and Zn (1482/637) which decreased exponentially with distance from the smelter and with soil depth. The metal concentrations in the organic layers indicate that the average transport distance decreases in the order Cd > Zn > Pb > Cu. With regard to metal partitioning, NH₄NO₃- + NH₄OAc-extractable forms in the A horizons were most affected by the deposition being more pronounced under forest. In the uppermost 50 cm of the four soils nearest to the smelter two to four times higher Cd, Cu, Pb, and Zn storages were found in forest than in arable soils. At greater distance, the higher deposition onto forest soils due to the scavenging effect of the canopy obviously was compensated by stronger leaching.     

Long-Range Atmospheric Transport and Local Pollution Sources on PAH Concentrations in a South European Urban Area. Fulfilling of the European Directive

A 12 months study on urban atmospheric concentrations of polycyclic aromatic hydrocarbons (PAH) contained in the particulate matter with an aerodynamic diameter less than or equal to 10 microns (PM10) was carried out in Zaragoza (Spain) from July 12th, 2001 to July 26th, 2002 by using a high-volume air sampler able to collect the PAH supported on a Teflon-coated fibre glass filter. Samples were analysed by using Gas Chromatography Mass Spectrometry (GC-MS/MS). PAH of high molecular weight, indeno[1,2,3-cd]pyrene (IcdP), benzo[g,h,i]perylene (BghiP) and coronene (Co) were the most abundant compounds. The concentrations of benz[a]pyrene equivalent carcinogenic power (BaP-eq) showed a mean value of 0.7 ng/m³ with 22.5% of the samples exceeding the 1.0 ng/m³ guide value established by the European Directive. These episodes were mainly produced during cold season. Regarding meteorological variables, a positive effect of the prevalent wind “cierzo” (NW direction) over the Zaragoza city was confirmed from the environmental point of view. The NE, E and S directions, corresponding to highway and industrial areas were the directions showing the high PAH atmospheric concentrations. Despite the proximity of a high-level traffic highway, stationary sources related to industry were the dominant source of PAH in the sampled area. Vehicular emissions and natural gas home heating also contributed to PAH concentrations. The predominance of local pollution sources versus long-range transport on PAH concentrations was shown. However, the contribution of long-range transport of anthropogenic origin from other European areas was reflected for specific dates on PAH concentrations and PM10 levels.     

Phenological Disorder Induced by Atmospheric Nitrogen Deposition: Original Causes of Pine Forest Decline over Japan. Part I. Phenological Disorder,Cold Death of Apical Shoots of Red Pine Subjected to Combined Exposures of Simulated Acid Rain and Soil Acidification,and Implications for Forest Decline

Seeds of red pine (Pinus densiflora Sieb. and Zucc.) were sown in red-yellow soil artificially adjusted to pH (H₂O) 4.10, 4.60 or 5.90 by adding H₂SO₄ solution to the soil (pH 5.90), and the three-month seedlings were exposed to simulated acid rain at pH 2.0, 3.0 or 5.6 for 10 minutes once, 3 times a week, for 12 months from 4 August 1994 to 3 August 1995 alone or in combination. Significant interactive effects between acid rain and soil acidification on growth and whole-plant net photosynthetic rate, and cold death ratio of new apical shoots following a cold snap were observed in a quadratic response pattern. The simulated acid rain increased budburst, new needle spread and elongation, and new apical shoot death percentage following a cold snap, but did not induce visible injury. In the highest soil acidity treatment at a soil pH 4.1, whole-plant net photosynthetic rate and seedling height exhibited a quadratic responses with increasing rain acidities. On the other hand, soil acidification caused leaf yellowing. The death percentage of new apical shoot of seedlings exposed to rain pH 2.0 following a cold snap was linearly enlarged with increasing soil acidities. With increasing soil acidity, height and whole-plant net photosynthesis of the seedlings exposed to rain pH 3.0 exhibited a linear increase response, while height of seedlings exposed to control rain exhibited a quadratic response. It is suggested that the results provide experimental evidency for phenological disturbances and an enhancement of frost risk by direct acid rain and indirect longterm soil acidification which may be significant in forest decline.     

Long-Term Changes in Forest Growth: Potential Effects of Nitrogen Deposition and Acidification

In spite of numerous experimental studies, it has, sofar, not been possible to link historic changes inforest growth to acid deposition at regional scales,partly due to difficulties in modeling the ecologicalcomplexity of forests. We analyzed radial incrementdata from increment cores from >31 000 spruce forestplots in southern Norway from 1954–1996. Using acombination of a bio-stratification model to controlconfounding factors, and a catchment model foracidification, we demonstrate for the first time aspatial and temporal co-variation between forestgrowth and both nitrogen deposition and acidification,as indicated by acidity critical loads exceedances.Increases in growth during the 1960–1970s, followed bya subsequent decline in the 1980–1990s, were bestexplained by combined actions of acidification,nitrogen deposition and climatic stress on forestgrowth. While forest conditions varyprimarily with natural growing conditions, the resultssuggest that boreal forests are sensitive to moderatelevels of nitrogen and sulphur deposition whereacidity critical loads are low, and that effects maybe observed over relatively short time scales.     

Effects of Atmospheric Sea-Salt Deposition on Soils and Freshwaters in Northeast Scotland

The majority of Scottish upland soils are particularly sensitive to acid deposition because of their low weathering rates. The compositions of the exchangeable base cations of such soils in the United Kingdom are dominated by sea salt inputs rather than by mineral weathering inputs of base cations. Catchments with low mineral weathering rates are also those particularly susceptible to freshwater acidification. Therefore, catchments exhibiting a high sea salt effect should also exhibit the most acid waters under base flow and storm flow conditions. A field evaluation study based on 61 catchments in NE Scotland has shown that this is indeed the case. River water pH under both base flow and high flow conditions is correlated stronhly with the relative contribution of Na+ to the sum of Ca2+, Mg2+ and Na+. From these results, an attempt is being made to produce a quantitative signature of weathering for the soils within the catchment upstream of the sampling point. Representative soil samples from the LFH, AE, B and C horizons and on 4 different parent materials have been obtained from the surrounding catchments to validate the above results for associated soil solutions. Sampling took place on upland moorland podzols under Calluna vulgaris. Tension lysimeters were used to sample the soil solutions so that their chemistry could be compared with that of the relevant river water.     

Studies on Atmospheric Pollution,Acid Rain and Emission Control for their Precursors in Chongqing,China

Chongqing City in China has suffered from serious air pollution and acid rain caused by low graded raw coal (sulfur=ca. 3≈5%, ash=ca. 30%) combustion. In this paper, the situation of atmospheric pollution and acid rain in Chongqing are discussed, the reduction efficiency for sulfur dioxide (SO₂) with the bio-briquetting of the raw coal that is one of countermeasures for emission control of air pollutants due to domestic consumes was determined. The research indicated that the frequency of acid rain was high, more than 50% at urban area, and its pH was low, about 4.5. Under our experimental conditions, the reducing efficiency of sulfur SO₂ emission from high sulfur coal-biomass briquette amounted to 87%. The field investigation indicated that SO₂ indoor concentrations in case of using bio-briquette dropped to 1/2≈1/3 of the raw coal.     

Long-Term Monitoring of Atmospheric Deposition and the Implications of Ionic Inputs for the Sustainability of a Coniferous Forest Ecosystem

Ionic fluxes in a semi-mature stand of Sitka spruce (Picea sitchensis (Bong.) Carr.), on a spodosol in eastern Ireland, were monitored over an eight-year period, 1991–1998. The paper focuses on the long-term viability of forests in this region. Input-output balances, proton budgets and critical loads suggest that the long-term sustainability of forests in the region is threatened unless atmospheric emissions of anthropogenic substances can be controlled.     

概述酸沉降对加拿大鱼类和渔业资源的影响及评价方法

本文概述了淡水资源及其产业在加拿大经济中的重要性、酸沉降对加拿大渔业资源造成的损失。通过现场调查、生物测定和试验研究探索了酸沉降对湖泊等水域酸化的影响。〔H~+〕是危害鱼类的主要毒物。提出利用模型评价酸沉降对生物损害是今后的发展趋势。     

海南岛热带雨林区芽孢杆菌收集及Bt菌鉴定

本研究系统地对海南岛热带雨林自然保护区进行了土壤样品的采集、芽孢杆菌的分离收集和Bt菌株的鉴定。从尖峰岭热带雨林区、五指山热带雨林区、吊罗山热带雨林区、霸王岭热带雨林区总共采集了土壤样品1882份,采用醋酸钠培养基结合高温方法分离出芽孢杆菌3924份,鉴定出Bt分离株158份,Bt菌株的分离率和出菌率分别为4.03％和8.40％。结果分析表明,海南岛热带雨林区芽孢杆菌及Bt菌株分布对环境和生态表现出一定的规律性,一般海拔900m至1400m的反菌株含量高、植被覆盖率高,土壤腐殖质含量高的热带沟谷雨林带眈菌株含量最高。显微观察发现,获得的Bt菌株其伴胞晶体有菱形、球形、方形、椭球形、不定性等多种形状。利用SDS-PAGE方法对获得的Bt分离株进行了伴胞晶体进行分析,发现伴胞晶体的分子量有20kD到150kD不等。进一步利用PCR-RFLP技术对Bt分离株进行了cry基因型的分析,初步发现这些Bt菌株含有cry1、cry3、cry4、cry6、cry30、cry40等基因型。我们还利用鳞翅目昆虫小菜蛾和鞘翅目昆虫椰心叶甲进行部分Bt分离株的生物测定,初步结果显示本研究鉴定出的Bt分离株具有不同的抗虫靶标,对同一靶标昆虫也表现出不同的杀虫活性。整体而言,本研究结果显示出海南岛热带热带雨林自然保护区因其独特的热带地理生境、自然的生物演化系统,使得热带雨林区蕴藏了Bt菌株资源多样化,值得期待挖掘出一些新的菌株和新的基因资源。     

Predicting Heavy Metal Concentrations in the Surface Sediments of Norwegian Headwater Lakes from Atmospheric Deposition: An Application of a Simple Sediment-Water Partitioning Model

Data from 96 headwater lakes from Norway are used to model heavy metal concentrations in surficial lake sediments in relation to atmospheric deposition. The study evaluates the application of sediment-water partitioning models at the field scale and finds optimum values for the partition coefficients. The impact of environment (sediment type, lake water pH, etc.) on K_Dvalues is explored directly by comparing K_Destimates with environmental variables. K_Dvalues for each metal are found by optimising the fit between predicted and observed surface-sediment concentrations. The sensitivity of the K_Destimates to data structure is examined by bootstrapping. K_Dvalues of 10^5.8and 10^6.2were calculated for cadmium (Cd) and lead (Pb), respectively, comparable to recent direct observations. Biogenic silica influenced K_Dvalues for Cd, Pb and Zn, whereas lake depth influenced Pb. pH did not have any detectable effect. K_Dfor zinc (Zn) was less well defined, but higher than indicated by published experimental measurements. The results suggest that sediment-water partitioning models have an important contribution to make to field-scale lake studies of sediment heavy metals, and have important implications for palaeolimnological evaluations of heavy metal deposition.