Rainwater Chemistry Research Articles

The Recent State of Ambient Air Quality in Jakarta

Air pollution has become a growing concern, especially in urban cities with rapidly developing economies, increasing infrastructure and vehicular population, and reduced green spaces. Fossil fuel and transportation are the main source of pollutive particles (e.g., sulfur oxide and nitrous) released into the atmosphere. Once they have entered the atmosphere, these particles create health problems, degrade air quality, and cause acid rain. Seasonal investigations on rainwater chemistry and particulate matter pollution (SPM, PM10, and PM2.5) were conducted to understand the recent state of the ambient air quality in Jakarta, Indonesia. The characteristics of PM2.5 were also analyzed during Ied Al Fitr in 2016 and 2017. Based on the observational data, the ambient air quality in Jakarta improved during the period of our study (2000–2016). The chemical constituents, i.e., the anion and cation concentrations, in precipitation show decreasing trends starting from 2006. Moreover, the PM10 and SPM concentrations also decreased slightly. The causes of these favorable trends are climatic conditions—namely, an increasing trend of rainfall—and policy intervention. Additionally, an assessment during the feast of Ied Al Fitr in 2016 and 2017 indicated a further decrease in PM2.5 due to highly reduced inner-city traffic. These events exhibited an extreme reduction of the PM2.5 concentration in Jakarta.

Physicochemical factors and their potential sources inferred from long-term rainfall measurements at an urban and a remote rural site in tropical areas

Air pollution can be detected through rainwater composition. In this study, long-term measurements (2000–2014) of wet deposition were made to evaluate the physicochemical interaction and the potential sources of pollution due to changes of land use. The rainwater samples were obtained from an urban site in Kuala Lumpur and a highland-rural site in the middle of Peninsular Malaysia. The compositions of rainwater were obtained from the Malaysian Meteorological Department. The results showed that the urban site experienced more acidity in rainwater (avg=277mm, range of 13.8 to 841mm; pH=4.37) than the rural background site (avg=245mm, range of 2.90 to 598mm; pH=4.97) due to higher anthropogenic input of acid precursors. The enrichment factor (EF) analysis showed that at both sites, SO42−, Ca2+ and K+ were less sensitive to seawater but were greatly influenced by soil dust. NH4+ and Ca2+ can neutralise a larger fraction of the available acid ions in the rainwater at the urban and rural background sites. However, acidifying potential was dominant at urban site compared to rural site. Source-receptor relationship via positive matrix factorisation (PMF 5.0) revealed four similar major sources at both sites with a large variation of the contribution proportions. For urban, the major sources influence on the rainwater chemistry were in the order of secondary nitrates and sulfates>ammonium-rich/agricultural farming>soil components>marine sea salt and biomass burning, while at the background site the order was secondary nitrates and sulfates>marine sea salt and biomass burning=soil components>ammonia-rich/agricultural farming. The long-term trend showed that anthropogenic activities and land use changes have greatly altered the rainwater compositions in the urban environment while the seasonality strongly affected the contribution of sources in the background environment.

Chemical characteristics and source analysis on ionic composition of rainwater collected in the Carpathians "Cold Pole," Ciuc basin, Eastern Carpathians, Romania.

A study of precipitation chemistry was conducted for 11years (01 January 2006-31 December 2016) in the Ciuc basin, Eastern Carpathians, Romania. The studied area is an enclosed basin, also called "the Carpathians cold pole." All collected samples were analyzed for major cations and anions. HCO3- concentrations were calculated based on the empirical relationship between pH and HCO3-. The multiannual arithmetic mean of pH values was found to be 6.57. The lowest and highest pH values were measured in 2009 and 2013, being 6.57% lower, respectively, 7.57% higher than the multiannual mean. Only 3.31% of the studied rainwater samples indicate acidic character. In descending order, the majority of the samples are as follows: NH4+ >Ca2+ >SO42- >Cl- >HCO3- >NO3- >Na+ >K+ >Mg2+ >NO2- >H+. Principal component analysis (PCA) showed the NH4+, Ca2+, and Mg2+ contribution to the neutralization process and their sources. The anthropogenic origin of SO42- was supported by the high non-sea-salt fraction (NSSF) (~91%). The results of this study suggest that rainwater chemistry is strongly influenced by local natural and anthropogenic sources (agricultural activities) rather than marine sources. The pollutants in rainwater samples were mainly derived from calcareous and dolomitic soil dust and specific local climatic conditions, long-range transport, local industry, and traffic sources.

The effect of sources and air mass transport on the variability of trace element deposition in central Poland: a cluster-based approach

Measurements of trace element (As, Cu, Cd, Cr, Ni, Pb, Zn) deposition fluxes were conducted simultaneously in two contrasted environments, i.e., urban and forest, between April 2013 and October 2014. This was the first such project in central Poland, aimed at long-term observations of trace elements in the atmosphere and their distribution, transport, and deposition pattern. The receptor sites were different in terms of local meteorological conditions, emission potential, and distance to major anthropogenic sources. The deposition fluxes of all trace elements showed clear seasonal variations, with relatively higher values in winter than in summer. The main factors affecting interannual differences in concentrations and deposition of trace elements in central Poland were local emission from industrial and commercial sources, and changes in atmospheric conditions (wind speed and direction, boundary layer, precipitation amount, air mass origin). In this study, the impact of regional and long-range transport on trace element deposition was determined using the air back-trajectory cluster analysis. During the summertime of 2013 and 2014, the predominant SW and E advections from regional and remote anthropogenic sources in Europe were responsible for high deposition of Cd, Cr, Pb, Cu, and Zn, whereas during the wintertime of 2013/2014, we observed a significant influence of polluted air masses from southeastern regions. Based on the Pb/Zn ratio, it was found that regional sources significantly influenced the aerosol composition and rainwater chemistry within the study domain. However, the role of a long-range transport of anthropogenic pollutants was also important. In addition, a relatively small difference in the Pb/Zn ratio between both sites (urban 0.26 ± 0.18, forest 0.23 ± 0.17) may suggest (1) very similar contribution of anthropogenic sources and (2) minor importance of atmospheric transformation processes of these metals in the aqueous phase.

Impacts of peat bulk density, ash deposition and rainwater chemistry on establishment of peatland mosses

Background and aimsPeatland moss communities play an important role in ecosystem function. Drivers such as fire and atmospheric pollution have the capacity to influence mosses via multiple pathways. Here, we investigate physical and chemical processes which may influence establishment and growth of three key moss species in peatlands.MethodsA controlled factorial experiment investigated the effects of different peat bulk density, ash deposition and rainwater chemistry treatments on the growth of Sphagnum capillifolium, S. fallax and Campylopus introflexus.ResultsHigher peat bulk density limited growth of both Sphagnum species. S. capillifolium and C. introflexus responded positively to ash deposition. Less polluted rain limited growth of C. introflexus. Biomass was well correlated with percentage cover in all three species.ConclusionsPeat bulk density increases caused by fire or drainage can limit Sphagnum establishment and growth, potentially threatening peatland function. Ash inputs may have direct benefits for some Sphagnum species, but are also likely to increase competition from other bryophytes and vascular plants which may offset positive effects. Rainwater pollution may similarly increase competition to Sphagnum, and could enhance positive effects of ash addition on C. introflexus growth. Finally, cover can provide a useful approximation of biomass where destructive sampling is undesirable.

Monthly Characteristics of Rainwater Chemistry at a Coastal Site in Southwestern Japan

Monthly Characteristics of Rainwater Chemistry at a Coastal Site in Southwestern Japan

The impact of air pollutants on rainwater chemistry during “urban‐induced heavy rainfall” in downtown Tokyo, Japan

AbstractIn order to clarify the impact of air pollution on the formation of sudden and locally distributed heavy rain in urban areas (hereafter UHR = urban‐induced heavy rain), we analyzed inorganic ions in rainwater samples collected on an event basis over 5 years from October 2012 to December 2016 in Shinjuku, Tokyo. Hourly rainfall amounts and wet deposition fluxes of acidic components (the sum of H+, NH4+, NO3−, and nonsea‐salt SO42−) in UHR were 13.1 and 17.8 times larger than those in normal rainfall, respectively, indicating that large amount of air pollutants were scavenged and deposited by UHR with large amounts of rainfall. The level of air pollutants, such as NO2, SO2, and potential ozone, in the ambient air increased just before the formation of UHR and decreased sharply at the end of the UHR event. These results indicate that NO2, which was formed secondarily by oxidants, was further oxidized by HO radicals and formed HNO3 just before the formation of UHR, which was subsequently scavenged by UHR.

Characterization of rainwater chemical composition after a Southeast Asia haze event: insight of transboundary pollutant transport during the northeast monsoon.

Open biomass burning in Peninsula Malaysia, Sumatra, and parts of the Indochinese region is a major source of transboundary haze pollution in the Southeast Asia. To study the influence of haze on rainwater chemistry, a short-term investigation was carried out during the occurrence of a severe haze episode from March to April 2014. Rainwater samples were collected after a prolonged drought and analyzed for heavy metals and major ion concentrations using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. The chemical composition and morphology of the solid particulates suspended in rainwater were examined using a scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The dataset was further interpreted using enrichment factors (EF), statistical analysis, and a back trajectory (BT) model to find the possible sources of the particulates and pollutants. The results show a drop in rainwater pH from near neutral (pH 6.54) to acidic (<pH 4.00) during the haze to non-haze transitional period, suggesting that the deposition rate of sulfate and nitrate in the atmosphere via the precipitation process was relatively lower compared to the mineral components. Zinc, nitrate, and calcium, which were the predominant elements in the first rainwater samples. Besides, the results of the SEM-EDS indicated that the zinc was possibly originated from anthropogenic activities which are consistent with the results obtained from EF. The BT model showed that pollutants transported from the mainland of Indo-China and the marine region in the South China Sea were responsible for the high pollution event in the study area. These findings can be useful in identifying contributions of pollutants from single or multiple sources in rainwater samples during haze episodes.

Chemical and Sr isotopic characteristics of rainwater on the Alxa Desert Plateau, North China: Implication for air quality and ion sources

The major ions and Sr isotopes in rainwater have been studied during 2013–2015 on the Alxa Desert Plateau in order to identify the source of rainwater chemistry and to assess air quality in the desert area of northern China. The pH and EC values of rainwater vary from 6.7 to 8.1 and from 35 to 1237μScm−1, respectively, at the two meteorological stations (AYQ and YBL) in the Alxa Desert Plateau. Ca2+, SO42−, Na+ and Cl− are the dominant ions in rainwater, possessing >85% of total ions. The mean daily wet deposition fluxes of soluble ions are 8709μeq/m2/d at YBL and 5459μeq/m2/d at AYQ, approaching the values at Xi'an, Beijing, Guangzhou, and Chengdu. Statistical analysis shows that SO42− and NO3− in rainwater were mainly from anthropogenic sources while Ca2+ and K+ originated from terrestrial sources. Cl− was mainly from seawater sources, and Na+ was partly from mineral weathering. Major ions are well correlated with each other in rainwater, revealing that substances of various origins were synchronously carried into the atmosphere by wind. By using Sr isotope techniques, three main end-members controlling base cations of rainwater are identified: silicates, carbonates and seawater. Based on the analyses of acid-soluble fractions of desert soils, local soil dust could be the most important source of base cations in rainwater whereas the effect of the anthropogenic sources could be neglected.

Spatial and Temporal Variation of Rainwater Chemistry in Ile-Ife and Its Environ, Osun State, Nigeria

The study of the chemical composition of rain water was conducted in Ile – Ife and environs, an agrarian, commercial, residential and semi-industrialised center of Osun state Nigeria. This was with a view to assessing the impact of land use activities on rain water composition and the temporal variation of rainwater chemistry. Physico-chemical parameters such as Turbidity, pH, TDS, Conductivity, Oxygen parameters, Alkalinity, Acidity, Hardness and Major ions (Ca2+, Mg2+, K+, Na+, NO3-, SO4-, HCO3-) were determined, predominant ions were identified. Turbidity, pH, Conductivity, TDS, D.O B.O.D, Alkalinity, Acidity Hardness ranged between 2.90 - 42.84 NTU, 5.65 - 7.40, 6.71 – 122.33 µScm-1, 4.10 –73.27 mg/L, 3.60 – 10.60 mg/L, 0.13 – 7.20 mg/L, 0.33 – 22.0 mg/L, 2.00 – 15.00 mg/L, 0.04 – 1.23 CaCO3mg/l respectively. The dominant ions detected in the study were HCO3-, Mg2+, Na+ and Ca2+. Generally, the mean concentration of ions as expressed in milli-equivalent per Litre showed order of dominance as HCO3- &gt; NO3- &gt; SO42- for the anions and Mg2+ &gt; Na+ &gt; Ca2+ &gt; K+ for cations. The study concluded that land use activities had influence on all the chemical composition of rain water in the study area but more on pH, alkalinity, acidity, bicarbonate. Except sulphate and Nitrate, all other parameters recorded high values in dry season.

ASSESSMENT OF MAJOR IONIC COMPOSITIONS AND ANTHROPOGENIC INFLUENCES IN THE RAINWATER OVER A COAL MINING ENVIRONMENT OF DAMODAR RIVER BASIN, INDIA

In the present study, 45 rainwater samples were collected from February to December 2012 on event basis in East Bokaro coal mining environment. Physico-chemical and major ionic compositions of rainwater samples as well as water soluble major ion composition were analyzed to employ principle component analysis for source identification. The average pH value was recorded 6.1 and varied from 5.1 to 6.9 in the collected rainwater samples, indicating slightly acidic to alkaline in nature. The rainwater chemistry of the region showed high contribution of HCO3- (32%) followed by SO42- (30%), Cl- (20%), NO3- (15%) and F- (3%) in anionic abundance. In case of major cations, Ca2+ (29%) was dominant followed by Mg2+ (27%), NH4+ (22%), Na+ (18%) and K+ (4%). The ratio of Cl-/Na+ in the rainwater samples was found to be almost equal to sea water. Higher enrichment of Na+ and Cl- concentration may be due to marine contribution. The EFs were found to be high for HCO3-, Ca2+, SO42- and K+ indicating sources other than sea; i.e., coal mining and other anthropogenic activities. The principle component analysis for ionic source identification was synthesized into four factors with eigen values cut off at greater than unity and explained about 71.8 % of the total variance. The rainwater quality area is mainly influenced due to mining activities, vehicular pollution and industrialization in the East Bokaro coalfield area.

Stable chlorine isotopes in arid non-marine basins: Instances and possible fractionation mechanisms

Stable chlorine isotopes are useful geochemical tracers in processes involving the formation and evolution of evaporitic halite. Halite and dissolved chloride in groundwater that has interacted with halite in arid non-marine basins has a δ37Cl range of 0 ± 3‰, far greater than the range for marine evaporites. Basins characterized by high positive (+1 to +3‰), near-0‰, and negative (−0.3 to −2.6‰) are documented. Halite in weathered crusts of sedimentary rocks has δ37Cl values as high as +5.6‰. Salt-excluding halophyte plants excrete salt with a δ37Cl range of −2.1 to −0.8‰. Differentiated rock chloride sources exist, e.g. in granitoid micas, but cannot provide sufficient chloride to account for the observed data. Single-pass application of known fractionating mechanisms, equilibrium salt-crystal interaction and disequilibrium diffusive transport, cannot account for the large ranges of δ37Cl. Cumulative fractionation as a result of multiple wetting-drying cycles in vadose playas that produce halite crusts can produce observed positive δ37Cl values in hundreds to thousands of cycles. Diffusive isotope fractionation as a result of multiple wetting-drying cycles operating at a spatial scale of 1–10 cm can produce high δ37Cl values in residual halite. Chloride in rainwater is subject to complex fractionation, but develops negative δ37Cl values in certain situations; such may explain halite deposits with bulk negative δ37Cl values. Future field studies will benefit from a better understanding of hydrology and rainwater chemistry, and systematic collection of data for both Cl and Br.

Rainwater chemistry and bulk atmospheric deposition in a tropical semiarid ecosystem: the Brazilian Caatinga

We assessed the rainwater chemistry, the potential sources of its main inorganic components and bulk atmospheric deposition in a rural tropical semiarid region in the Brazilian Caatinga. Rainfall samples were collected during two wet seasons, one during an extremely dry year (2012) and one during a year with normal rainfall (2013). According to measurements of the main inorganic ions in the rainwater (H+, Na+, NH4 +, K+, Ca2+, Mg2+, Cl−, NO3 −, and SO4 2−), no differences were observed in the total ionic charge between the two investigated wet seasons. However, Ca2+, K+, NH4 + and NO3 − were significant higher in the wetter year (p < 0.05) which was attributed to anthropogenic activities, such as organic fertilizer applications. The total ionic contents of the rainwater suggested a dominant marine contribution, accounting for 76 % and 58 % of the rainwater in 2012 and 2013, respectively. The sum of the non-sea-salt fractions of Cl−, SO4 2−, Mg2+, Ca2+ and K+ were 19 % and 33 % in 2012 and 2013, and the nitrogenous compounds accounted for 2.8 % and 6.0 % of the total ionic contents in 2012 and 2013, respectively. The ionic ratios suggested that Mg2+ was probably the main neutralizing constituent of rainwater acidity, followed by Ca2+. We observed a low bulk atmospheric deposition of all major rainwater ions during both wet seasons. Regarding nitrogen deposition, we estimated slightly lower annual inputs than previous global estimates. Our findings contribute to the understanding of rainfall chemistry in northeastern Brazil by providing baseline information for a previously unstudied tropical semiarid ecosystem.

Chemical characteristics of rainwater in Sichuan basin, a case study of Ya'an.

Rainwater chemistry was investigated at a semi-rural site in Ya'an, Sichuan basin with rain samples collected from May 2013 to July 2014. The rainwater pH values ranged from 3.25 to 6.86, with an annual volume-weighted mean (VWM) of 4.38, and the acid rain frequency was 74%. Such severe acidification, 15% of the total events showed a pH below 4.0, attributed to the deficiency of Ca(2+), significant anthropogenic pollution contribution, and rainy pattern to this area. The annual VWM of total ions concentration was 477.19μeq/L. NH4 (+) was the most abundant ionic species, followed by SO4 (2-), NO3 (-), Ca(2+), Cl(-), Na(+), K(+), Mg(2+), and F(-) in a descending order. The total ionic concentrations presented a seasonal trend of lower values in autumn and summer but higher ones in winter and spring. Based on enrichment factor, correlation analysis and principle component analysis, three factors were identified: factor 1 (NH4 (+), SO4 (2-), NO3 (-), K(+), and Cl(-), 47.45% of the total variance) related to anthropogenic sources (coal/fuel combustion, biomass burning and agriculture), factor 2 (Ca(2+), Mg(2+), Na(+), and Cl(-), 34.01% of the total variance) associated with natural sources, and factor 3 (H(+), 11.78% of the total variance) related to free acidity. Back trajectory analysis indicates that the rainwater chemistry in Ya'an was mainly affected by regional air masses from Sichuan basin. Long-range transported air masses from southwest with heavy anthropogenic pollution increased the total ion concentration and acidity of rainwater. Considering its special topography, anthropogenic emissions from regional and long-range transport (especially from southwest) must be controlled effectively to improve the acid rain condition of non-urban areas in Sichuan basin.

Chemical composition and source identification of rainwater constituents at an urban site in Xi’an

Major ions, pH and electric conductivity (EC) in rainwater samples collected from June 2011 to July 2012 were analyzed to evaluate chemical characteristics and source apportionment of rainwater in Xi’an, a city located on the loess deposits. The rainwater was slightly alkaline with a daily volume-weighted mean (VWM) pH of 7.7, which ranged from 7.4 to 8.4. The VWM concentrations of major ions followed the order of Ca2+ > SO42− > NH4+ > NO3− > Cl− > Na+ > K+ > Mg2+ > F−. Ca2+ and SO42− dominated in cations and anions, respectively. Investigations of neutralization factors indicated that the acidity of rainwater in Xi’an was neutralized by NH4+ and Ca2+, which presented relatively higher neutralization capability than cities in southern China. The back trajectory analysis showed that the chemistry of rainwater in Xi’an is influenced by local pollutions sources and soil dust in local and remote area. Large inputs of soil dust and coal combustion during the winter and spring led to higher values of major ions and pH values during dry seasons than wet seasons. The principal factor analysis, correlation analysis, and source apportionment indicated that SO42− and NO3− were from anthropogenic sources, while Ca2+, K+, and Mg2+ were from crust fractions. The estimated annual wet depositions for sulfur, nitrogen, and calcium were 3.9, 1.5, and 4.2 t/km2, respectively. Although rainwater acidity in Xi’an was mainly caused by H2SO4, the contribution of HNO3 will be enhanced due to increasing NOx and relatively stable SO2 emissions in the future. The high concentrations of EC, SO42−, and NO3− in rainwater indicated Xi’an is severely polluted. To improve air quality in Xi’an, simultaneous reduction of particle emissions and fossil fuel and vehicles emissions are worthy of advocating. The results have implications for identification of potential sources in rainwater and for evaluation of air quality improvement in Xi’an and other similar cities in China.

Surface Water Acidification due to Vehicular Industrial and Anthropogenic Activity: Bhubaneswar City—A Case Study

This paper presents the seasonal analysis reports of the chemistry of rainwater, surface water and fog of Bhubaneswar city for three years, i.e., July 2008 to June 2011. In this study 838 rain water samples, 342 fog samples and 658 surface water samples have been collected from twelve different are as such as, Acharya Vihar, Saheed Nagar, Bapuji Nagar, Forest Park, Nalco Chhak, Sailashree Vihar, Patia, Chandaka Forest range, Baramunda, Khandagiri, Palaspalli and Kausalyaganga. The present study reports about the occurrence of acid rain, formation of fog and smog and their rate of contamination to the surface water changing its pH and nutrient content. The water sample collected from Acharya Vihar, Bapuji Nagar and Kausalyaganga area were found to be highly acidic in nature (pH < 5.2). It has been observed that pH of the rain water varies within the range of 4.3 to 5.0 and fog water sample in the range of 4.2 to 4.8 respectively. It has been found that the water sample obtained from other areas are slightly acidic in nature where the pH of the surface water remains in the range of 5.5 to 5.8. It has been observed that the water sample in high acidic area is found to be more loaded with heavy metal in comparison to the water obtained from low acidic area. A correlation has been established by the critical analysis of both the water samples (atmospheric and surface).

Nature and Sources of Ionic Species in Precipitation across the Indo-Gangetic Plains, India

ABSTRACTThe spatial distribution of rainwater chemistry over the densely-populated and highly polluted Indo-Gangetic Plains (IGP) was investigated using samples (total = 687) collected during three consecutive summer monsoon seasons from 2009 to 2011. The concentrations of secondary ionic species (SO42– and NO3–) were measured along with the other major ions (F–, Cl–, Na+, K+, Ca2+, Mg2+ and NH4+) and pH and specific conductivity. The weighted mean pH (± std) and conductivity of rainwater were 5.73 (± 0.17) and 31.6 (± 31.0) µS cm–1, respectively. Approximately 16% of rainwater samples were acidic (pH 5.61) (mean pH = 6.34 for the more basic samples). Specific conductivity was ~39% lower (20.6 µS cm–1) for the acidic rain compared to the more basic (33.6 µS cm–1) samples. The mean sum of all of the measured ions is 351.6 ± 130.1 µeq L–1 with the highest contributions being Ca2+ (30%) and SO42– (15%). Mean [SO42–] (52 µeq L–1) and [NO3–] (29 µeq L–1) were approximately five and ten times higher, respectively, compared to background hemispheric values. Secondary ions had the highest deposition fluxes (SO42–, 25.2 kg ha–1 y–1 and NO3–: 18.3 kg ha–1 y–1). The mean ratio of H+/(NO3– + SO42–) was 0.02 indicating ~98% of the acidity was neutralized. Ca2+, (57%), Mg2 (25%), NH4+ (15%) and K+ (4%) were important neutralizing species. Positive Matrix Factorization (PMF) was applied to the deposition fluxes. Five factors were identified and identified as ammonia neutralized, sea salt, soil, biomass burning, and calcium neutralized.

Study of Trace Ions in Wet Deposition of an Industrial Site in Monterrey’s Metropolitan Area, Mexico

The chemistry of rainwater has been subject to numerous investigations during the last two decades due to the increase of environmental problems caused by the acid deposition. The present study focuses on one aspect of air pollution, the chemical composition of wet deposition of an industrial zone. The sampling period was from March to December 2009. The station was located on the roof of the Chemistry School at the University of Nuevo Leon, an area in the north of Monterrey where the majority of pollution is generated. Twenty-five wet precipitation samples were collected with an automatic sampler and analyzed for pH, ions (, , Cl&#45, Ca2+, Mg2+, Na+, K+) and conductivity. The results show that the average pH is higher than 5.6; the characteristics of the rainwater studied are of alkaline nature due to the values of pH found; there is an evident anthropogenic source contributing to the alkaline of rain water. In order to find possible association between ions and consequently the possible sources of pollutants correlation study was applied using the program SPSS v.12. Good correlations were found between ions and along with Ca2+ and Mg2+. The local extraction industry and surrounding aerosols might be causing of alkaline rain which may be due to the neutralization effect of particulate matter. This study represents a continuation of the studies of rainwater chemistry in the Northeast of Mexico.

A study on the precipitation in Izmir, Turkey: chemical composition and source apportionment by receptor models

The chemistry of rainwater was studied in three sites of a metropolitan city of Turkey to determine the spatial variation, sources affecting composition and the extent of their influence. The acidity of rainwater, Ca, Co, Cr, Zn, Ba, V and Ni showed significant spatial variations. The most of measured species were moderately to extremely enriched compared to the local soil, which is likely arisen from the anthropogenic activities. SO42−, K and Ca were found to be predominantly non-sea origin. Two receptor models, Positive Matrix Factorization (PMF) and Chemical Mass Balance (CMB), agreed well on the source contribution estimations of Al, K, Zn, V, Pb and Cr. The PMF and CMB resolved very similar source contribution profiles to the elemental concentrations of Ca, Zn, V, Pb, K and Na, which the majority of those resulted from mineral industries, bell casting+steel industries, fossil fuel burning, biomass burning+sea salt and sea salt, respectively. The PMF resolved the source contributions of long-transported emissions, particularly for Ba, Sr and Mn, which could not be estimated by the CMB.

Contributing factors in foliar uptake of dissolved inorganic nitrogen at leaf level

We investigated the influence of leaf traits, rainwater chemistry, and pedospheric nitrogen (N) fertilisation on the aqueous uptake of inorganic N by physiologically active tree leaves. Leaves of juvenile silver birch and European beech trees, supplied with NH4NO3 to the soil at rates from 0 to 200kgNha−1y−1, were individually exposed to 100μl of artificial rainwater containing 15NH4+ or 15NO3− at two concentration levels for one hour. In the next vegetative period, the experiment was repeated with NH4+ at the highest concentration only. The N form and the N concentration in the applied rainwater and, to a lesser extent, the pedospheric N treatment and the leaf traits affected the aqueous foliar N uptake. The foliar uptake of NH4+ by birch increased when leaves were more wettable. High leaf N concentration and leaf mass per area enhanced the foliar N uptake, and NO3− uptake in particular, by birch. Variation in the foliar N uptake by the beech trees could not be explained by the leaf traits considered. In the first experiment, N fertilisation stimulated the foliar N uptake in both species, which was on average 1.42–1.78 times higher at the highest soil N dose than at the zero dose. However, data variability was high and the effect was not appreciable in the second experiment. Our data suggest that next to rainwater chemistry (N form and concentration) also forest N status could play a role in the partitioning of N entering the ecosystem through the soil and the canopy. Models of canopy uptake of aqueous N at the leaf level should take account of leaf traits such as wettability and N concentration.