Composition Of Rainwater Research Articles

Rainwater chemistry at a regional representative urban site: influence of terrestrial sources on ionic composition

Abstract In the present investigation, the rainwater chemistry is studied over a one year period at a regional representative urban site, Tirupati. A continuous record of 67 events were included that ranged from 0.5 to 74.6 mm (annual total 850.2 mm), from which 35 events (52%) were chemically analyzed during the period for major inorganic ion composition viz. F, Cl, NO3, SO4, Na, K, Ca, and Mg as well as NH4. The volume-weighted mean (VWM) of the measured ionic sum is 501.28 μeq l−1 and the crustal ion contribution dominating over the acidic ions with a ratio of total cation to that of anions (Σcations/Σanions) is 1.4. Only the Ca and SO4 together made up more than 55% of the total ion, whereas Ca alone contributed about 51% of the total cation. All the rain samples analyzed showed alkaline pH always, to that of reference level 5.6, with VWM of 6.78. On the basis of good correlation between the crustal ions (Ca, Mg, K and NH4) and SO4 ( r = 0.95 ) and NO3 ( r = 0.91 ) as well as order of neutralization factors Ca (0.88)>Mg (0.33)>NH4 (0.11), it has been determined that the acid neutralization is brought about by crustal ions, particularly calcium, in the region. The data were subjected for correlation analysis. A good correlation observed between Ca and SO4 and NO3 ( r = 0.92 and 0.90) and Mg and SO4 and NO3 ( r = 9.83 and 0.77), respectively, reveals that the ionic composition of rainwater in the region is strongly influenced by terrestrial sources rather than anthropogenic and marine sources.

The chemical composition of rainwater over Büyükçekmece Lake, Istanbul

In the present study, the precipitation near Büyükçekmece Lake, which is one of the important drinking water sources of Istanbul city, was studied during October 2001–July 2002. Seventy-nine bulk precipitation samples were collected at two sampling stations near the Lake (41°2′35″N, 28°35′25″E and 41°5′30″N, 28°37′7″E). The study comprised the determination of H +, Cl −, NO 3 −, SO 4 2−, NH 4 +, Na, K, Mg, Ca, Al, Ba, Fe, Cu and Mn concentrations in bulk deposition rain event samples. The average volume-weighted pH value was found to be 4.81, which points out that the rain is slightly acidic. High sulfate concentrations were observed together with high H + ion values. Sulfur emissions were the major cause for the observed high hydrogen ion levels. On the basis of factor analysis and correlation matrix analysis, it has been found that in this region, acid neutralization is brought about by calcium rather than the ammonium ion. The varimax rotated factor analysis grouped the variables into four factors, which are crustal, marine and two anthropogenic sources.

Precipitation Chemistry in Semi-Arid Areas of Southern Africa: A Case Study of a Rural and an Industrial Site

Experimental data on the precipitation chemistry in the semi-arid savanna of South Africa is presented in this paper. A total of 901 rainwater samples were collected with automatic wet-only samplers at a rural site, Louis Trichardt, and at an industrial site, Amersfoort, from July 1986 to June 1999. The chemical composition of precipitation was analysed for seven inorganic and two organic ions, using ion chromatography. The most abundant ion was SO4 2 − and a large proportion of theprecipitation is acidic, with 98% of samples at Amersfoort and 94% at LouisTrichardt having a pH below 5.6 (average pH of 4.4 and 4.9, respectively). This acidity results from a mixture of mineral and organic acids, with mineral acids being the primary contributors to the precipitation acidity in Amersfoort, while at Louis Trichardt, organic and mineral acids contribute equal amounts of acidity. It was found that the composition of rainwater is controlled by five sources: marine, terrigenous, nitrogenous, biomass burning and anthropogenic sources. The relative contributions of these sources at the two sites were calculated. Anthropogenic sources dominate at Amersfoort and biomass burning at Louis Trichardt. Most ions exhibit a seasonal pattern at Louis Trichardt, with the highest concentrations occurring during the austral spring as a result of agricultural activities and biomass combustion, while at Amersfoort it is less pronounced due to the dominance of relatively constant industrial emissions. The results are compared to observations from other African regions.

Chemical characterization of rainwater at a developing urban habitat of Northern India

A comprehensive study of the chemical composition of rainwater was carried out from June 1999 to September 2001 at Lucknow, India. The rainwater was found to be alkaline with a mean pH of 6.7 in winter season and 6.5 in monsoons. It was observed during the study that Ca was the most abundant ion and along with Mg and NH 4 it forms equilibrium reactions with acids. Analysis of Variation (ANOVA) indicates that concentration of major ions was higher during cold climatic conditions probably due to dry season in winter leading to low dilution phenomena. The data was subjected to factor analysis based on Principal Component Analysis using the SPSS software (Version 7.5). The rotated factor matrix was employed to group variables into four factors. The first factor included Ca, Mg, SO 4, NO 3 and NH 4 attributed to soil derivatives and biogenic activities. Factor 2 loaded with Na, K, and Cl, may be linked to emissions from traditional combustion activities. Factor 3 and 4 include Cu, Zn, Fe and Ni, which may be attributed to industrial activities and scavenging process cycles.

Influence of rainfall quantity on the isotopic composition ( 18O and 2H) of water in mountainous areas. Application for groundwater research in the Yunquera-Nieves karst aquifers (S Spain)

The isotopic composition ( 18O and 2H) of rainwater and groundwater was determined in the Yunquera-Nieves hydrogeological unit, a karstic massif in S Spain with complex orography and hydrogeology. The aims were to identify: (1) the source of the water, (2) the main factors determining the isotopic content, (3) the catchment area of the springs and (4) the aquifer behaviour. The isotopic content of the sampled waters is of mixed Atlantic–Mediterranean origin and is opposite to the quantity of rainwater distribution, both in space and time. Spatially, water is isotopically less depleted toward the eastern sector, where rainwater quantity is lower (which is locally affected by the orography): thus, it is possible to differentiate the catchment areas of the main springs. Aquifer recharge is produced by winter precipitation, when rainfall water is isotopically more negative and evaporation is lower. The decrease in rainfall quantity during the study period provoked an increase in δ 18O and δ 2H values, both in rainwater and in groundwater. The recorded variations of the isotopic content of the rainfall are rapidly evident in the spring waters, which demonstrates a well developed karst network inside the carbonate aquifers, and thus the existence of conduit flow systems.

Hillslope‐swamp interactions and flow pathways in a hypermaritime rainforest, British Columbia

AbstractThe process of water delivery to a headwater stream in a hypermaritime rainforest was examined using a variety of physical techniques and tracing with dissolved organic carbon (DOC) and the stable isotopes of water. Headwater swamps, often the major discharge zones for water draining off steep forest slopes, strongly affect the physical and chemical character of streamflow in the region. The headwater swamp selected for detailed investigation was sustained by relatively constant groundwater input from the steep colluvial slopes that maintained the water table above the ground surface. During significant storm events the water table rose quickly and the swamp expanded to engulf marginal pools that developed rapidly on the adjacent ground surfaces. The corresponding release of surface water directly to the stream typically comprised up to 95% of total stream discharge. The proportion of groundwater seepage to the stream by matrix flow (<1%) and via macropore‐fed springs (up to 73%) increased during the recession period, but could not be sustained over the longer term. In more protracted drying periods, deep groundwater contributions to the stream were routed first to the headwater swamp.Dissolved organic carbon (DOC) in the stream, measured daily or more frequently during storm events, was found to be directly proportional to discharge, owing to the domination of DOC‐rich headwater‐swamp water sources. Although δ18O and δ2H composition of rainwater, groundwater and stream flow were found to be similar, deuterium excess (d  δ2H − 8δ18O) of water components was often found to be distinct, and suggested short water residence times of roughly 12 days for one event. Overall, observations of a typical headwater swamp reveal that the groundwater regime is dominated by rapid infiltration and short, emergent flow paths. With a relatively short turnover time, potential disturbances to the system by harvesting of upslope areas can be expected to occur rapidly. Forest managers can mitigate some of the harmful effects of logging operations by respecting the integrity of headwater wetland systems. The nature and magnitude of such perturbations will require further study. Copyright © 2003 John Wiley & Sons, Ltd.

A universal bias in inorganic rainwater chemical composition data

In the late 1970s, it was recognised that organic acids contributed to the acidity and ionic content of rainwater, but that these acids had not been detected because they were consumed biologically in the period between rainwater collection and subsequent laboratory analysis. Discussion of consequences for measured rainwater composition has been limited to assessment of pH gain that attends organic acid loss. We show that biological effects on rainwater ionic composition are not restricted to pH alone. Ammonium, potassium, nitrate, sulfate, methanesulfonate, and phosphate ions are also removed biologically, but remain in the rainwater in biomass, implying that most previous rainwater composition studies based on ionic analyses will have systematically underestimated nutrient deposition.

Chemical composition of rainwater around an industrial region in Mumbai : Naik, M. et al. Current Science, 2002, 82, (9), 1131–1137

Chemical analysis of rainwater samples collected at Kalyan, a downwind location of a large industrial belt, and at Alibag and Colaba, the upwind locations, during the southwest monsoon seasons of 1994 and 1995 and comparison with similar data of 1973-74 reveal that pH of rainwater at Kalyan which was alkaline 20 years ago became acidic due to long-term effect of pollutants. A decreasing trend in excess SO4 was observed at Colaba and Kalyan, which is attributed to the pollution control measures adopted by industries and switching over from coal to natural gas which contains low sulphur. Whereas the increasing trend in NOx observed at Kalyan and Colaba, is attributable to increased automobile emission.

Rainwater composition in northeast Uruguay

The chemical composition of rainfall in northeast Uruguay in 1999 and 2000 and the sources that contribute to the rainwater chemistry are assessed in this study, contributing to a limited knowledge base of rainwater quality in South America. Principal factor analysis and cluster analysis indicate that four main source groups influence the rainfall chemistry over a range of spatial scales. Terrigenous sources (e.g. rock, soil and dust) and agricultural sources (e.g. livestock and crop fertilization) contribute to rainwater chemistry on a local and sub-regional scale. Influx of marine air from the Atlantic Ocean has a regional-scale influence while biomass burning contributes at both a local and sub-regional scale (e.g. fuel wood, and agroindustries) and through long-range transport (forest fires and land clearing). As may be expected in this area dominated by agriculture, the concentrations of ions that are indicative of industrial emissions, NO 3 − and SO 4 2−, are typical of background measurements. The current data are limited, but provide an indication of rain quality and the sources that influence its chemistry in Uruguay. It may be inferred that large-scale biomass burning in the central parts of the continent influence rainwater chemistry on a scale far larger than indicated by the Uruguayan network. Similarly, but to lesser extent, the influx of marine air off the Atlantic Ocean has a greater regional-scale influence than suggested by these data.

Chemical characterization of rainwater at Singapore

A short term study of the chemical composition of rainwater was carried out from November 1999 to October 2000 in Singapore. The rainwater was typically acidic with a mean pH of 4.2. Sulfate was the most abundant ion and comparable to the results reported for other industrialized regions. The concentrations of major ions (NH 4 +, Ca 2+, K +, Na +, Mg 2+, SO 4 2+, NO 3 2−, Cl −, HCOO −, CH 3COO −) varied monthly. Results show that local meteorological conditions influence the chemical compositions to a significant extent. The pollutants in rainwater were derived from long range and local (industry and traffic) sources.

A rainwater quality monitoring network: a preliminary study of the composition of rainwater in Galicia (NW Spain)

A network consisting of 17 sampling stations strategically distributed in the geographical area of Galicia (NW Spain) was set up in January 1999 in order to monitorice the ionic rainwater quality in this Spanish region which has an area≈29.575 km 2 and a population of 2.8 million. This paper presents the preliminary results of the exploratory study on the ionic rainfall composition in this area during the first year. In each rainwater sample collected chloride, sulphate, nitrite, nitrate, phosphate, sodium, potassium, magnesium, calcium and ammonium were measured, as were pH, conductivity and precipitation-volume. An univariate study according to the location of each sampling site was performed. Multivariate chemometric techniques, such as principal component analysis and cluster analysis, were applied to the complete data set (consisting of 630 observations) in order to elucidate the factors affecting the ionic composition of rainwater.

Evaluation of Air Quality over the Black Sea: Major Ionic Composition of Rainwater

This article attempts to put the light on the air quality of the Black Sea region of Turkey. In addition to that, it endeavors to locate the possible sources of the different pollutants at local, regional and long range transported scales. About 196 rainwater samples were collected over the Black Sea region of Amasra between 1995 and 1999, and analyzed for major ions and trace elements using spectrophotometric techniques. Andersen wet only rain samples were used to collect rain events, where the rain sample was filtered inline using 0.45 μm cellulose acetate filters. Major anions (SO4 2-, NO3 - and Cl-) were determined using ion chromatography, whereas metals (Ca, Mg, Al, Fe, Na, K), werequantified using ICP-AES. This study shows that, the Black Sea region receives different amounts and types of anthropogenic pollutants via long-range transport according to trajectory models. Although the pH of rain water is not considered acidic (pH = 5.21) yet the neutralizing species are lower than other sites around Europe.

Chemical composition of aerosol, sea fog, and rainwater in the marine boundary layer of the northwestern North Pacific and its marginal seas

Samples of aerosol, sea fog, and rainwater were collected during a research cruise in the northwestern North Pacific, the Sea of Okhotsk, and the Sea of Japan in the summer of 1998. High concentrations of NO3−, nss‐SO42− and NH4+ in aerosol over the Sea of Japan suggest that anthropogenic substances were transported to this region. Although the Sea of Okhotsk was covered with a clean marine air mass, the concentration of nss‐SO42− was comparatively high in the aerosol samples. This nss‐SO42− is probably of marine biogenic origin. The pH values of fogwater samples were measured to be <3.0 over the Sea of Okhotsk and the Sea of Japan. The concentrations of NO3− and NH4+ in the fogwater collected over the Sea of Japan were higher than those in the other regions, suggesting that the sea fog scavenged anthropogenic substances. The concentration of nss‐SO42− in fogwater over the Sea of Okhotsk was equivalent to that over the Sea of Japan, probably because nss‐SO42− and SO2 of marine biogenic origin were scavenged by the sea fog over the Sea of Okhotsk. The pH values of rainwater samples ranged from 6.1 to 7.2 during the cruise, and acidification of the rain was not significant. The concentrations of nss‐Ca2+ in the rainwater were higher than those of the fogwater. This suggests that the rain‐scavenged continental CaCO3 may have existed above the lower marine boundary layer, where sea fog appeared. Comparisons of the composition of aerosol and fogwater indicated that coarse particles, such as sea salts predominantly act as condensation nuclei of sea fog droplets rather than fine particles such as (NH4)2SO4.

Wet deposition and related atmospheric chemistry in the São Paulo metropolis, Brazil: Part 1. Major inorganic ions in rainwater as evaluated by capillary electrophoresis with contactless conductivity detection

The metropolitan region of São Paulo (17.8 million inhabitants) presents serious air quality problems. An official network monitors key air pollutants, however, there is no regular program of evaluation of the wet deposition and data about rainwater composition is scarce. Opening a series of articles on this subject, capillary zone electrophoresis with contactless conductivity detection (CZE-CCD) is proposed and applied as a quick and inexpensive alternative to ion chromatography for the determination of the ionic composition of rainwater. Excellent resolution of the peaks and sufficient sensitivity were obtained for major ions. Switching from anion to cation determination is fast (30 min) and as simple as inverting the polarity of the voltage supply and changing the modifier added to the buffer solution. CZE-CCD was applied to the study of wet-only deposition collected in São Paulo during the period from May l997 to March 1998. The volume weighted means of the anions, sulfate, nitrate and chloride, were, respectively, 17, 22 and 29 μmol l −1. Among the cations, ammonium was the dominating one, with 28 μmol l −1, followed by calcium, 23 μmol l −1, sodium, 12 μmol l −1, and potassium, 5.8 μmol l −1. The wet flux of these anions and cations were, respectively, 2.5, 2.2, 1.6, 0.78, 1.4, 0.43 and 0.35 g m −2 yr −1. By attributing all sodium to marine origin, half of the chloride and more than 90% of all other ions are ascribable to continental/anthropogenic sources. Literature data for rainwater from inland regions (∼200 km apart from São Paulo) reveals lower deposition of all ions but H +. Absorption of NH 3 and incorporation of calcium carbonate, mainly in the metropolitan region itself, accounts for decreased acidity. The enrichment in all other ions during the studied period indicates the prevalence of the anthropogenic emissions from the metropolis over continental sources and explains the high correlation between the ions NO 3 −, SO 4 2−, and NH 4 +; the same ions responsible for a factor that, alone, explains 42% of the variability in the PCA.

Organic acids and aldehydes in rainwater in a northwest region of Spain

During a 1 year period, measurements of carboxylic acids and aldehydes were carried out in rainwater samples collected at nine different sites in NW Spain surrounding a thermal power plant in order to determine concentration levels and sources. In addition, certain major ions (Cl −, NO 3 −, SO 4 2−, Na +, NH 4 +, K +, Mg 2+, Ca 2+) were also determined. Aldehyde and carboxylic acid concentration patterns and their effects on rainwater composition concerning temporal, seasonal and spatial variations were evaluated. Among carboxylic acids, formic and acetic were predominant (VWA 7.0 and 8.3 μM), while formaldehyde and acroleine were the dominant aldehydes (VWA 0.42 and 1.25 μM). Carboxylic acids were estimated to account for 27.5% of the total free acidity (TFA), whereas sulphuric and nitric acid accounted for 46.2% and 26.2%, respectively. Oxalic acid was demonstrated to be an important contributing compound to the acidification in rainwater representing 7.1% of the TFA. The concentration of aldehydes and carboxylic acids, which originated mainly from biogenic emissions in the area studied, was strongly dependent on the season of the year (growing and non-growing). The ratios of formic to acetic acids are considerably different in the two seasons suggesting that there exist distinct sources in both growing and non-growing seasons. Principal component analysis was applied in order to elucidate the sources of aldehydes and organic acids in rainwater. The prevalence of natural vegetative origins for both of these compounds versus anthropogenic emissions was demonstrated and the importance of the oxidation of aldehydes as a relevant source of organic acids was also established.

Chemical composition of rainwater at EMEP station in Ankara, Turkey

The chemical characteristics of rainfall and its seasonal variation at the EMEP (The Cooperative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe) station located in Cubuk, Ankara were studied for the period between September 1994 and December 1996. The station is located in a rural area about 50 km north of Ankara and is considered as a background station for air pollution. The rainwater samples collected were analyzed for pH, major ions concentrations and conductivity. Seasonal variations for some major ions are pronounced. Generally, maximum concentrations appeared in winter or autumn, and minimum concentrations in spring or summer seasons. The average pH of rainwater samples is around 6.3 due to neutralization. Only about 4% of the rain samples had a pH below 5.0 and about 15% of the total rainwater samples had a pH below 5.6. This reflects strong inputs of alkaline species to rainwater samples in this location. The average pH of the samples higher than 5.6 observed in rural area of Ankara is due to a high loading of calcium ions in the form of CaCO 3 because of the alkaline nature of the soil. There is a strong relationship between pHs and other ions in summer. However, in winter, a weak relationship is found between SO 4 2−, NO 3 −, Na + and Mg 2+. On the other hand, relationships between the conductivity and SO 4 2− concentration are stronger in summer than in winter. The low concentrations of H + found in rainwater samples from Cubuk suggests that an important portion of H 2SO 4 and HNO 3 have been neutralized by alkaline particles in the atmosphere. Weak correlations are found between the hydrogen ions and SO 4 2− or NO 3 − ions for all seasons because of neutralization of these ions with alkaline particles. The dust-rich local and surrounding limestone environment might have caused the high concentration of Ca 2+ in Cubuk area. The relatively high concentration of NH 4 + observed at Cubuk is suspected to be due to surrounding agricultural activity. This agricultural activity has been found to be effective not only in spring, but also in autumn and winter to cause neutralization of the rainwater.

Studies on Intercorrelation between Ions Co-Occurring in Precipitation in the Gdańsk-Sopot-Gdynia Tricity (Poland)

The paper presents monitoring results and environmental pollution assessment for the Gdansk-Sopot-Gdynia Tricity (Poland), based onanalysis of precipitation. Precipitation samples were collected over a period of 12 months (January–December 1998) at ten locations in the Tricity. The following selected ions were determined in the samples:SO42−, F−, Cl−, NO3−,PO43−, NH4+, Na+,Mg2+, Ca2+, K+. The results were subjected to full statistical evaluation. Values of the parameters determined were correlated with each other. An attempt was made to explain co-occurrences of certain ions and the significance of their mutual effects. Pollutant concentrations and loads in precipitation were also correlated with data on wind direction and temperature in the region.Deposition of pollutants was very high in spring due to the prevailing air circulation patterns and low temperatures. Analysis of the correlations between co-occurring ions confirmed the significant impact of the location (sea coast) on the composition of rain water. Ionic ratios in rainwater were similar to those observed for sea salt samples. In addition, heavy traffic was most probably responsible for high concentrations of various forms of nitrogen and sulphates in the vicinity of major highways.

Rainwater Composition and Acidity at Five Sites in Malaysia, in 1996

Rainwater chemical composition and acidity were determinedfrom weekly-averaged wet-only rainwater samples collected atfive sites in Malaysia throughout 1996. The major aim of thiswork was to assess the extent to which acid deposition, foundpreviously at one site in the Klang Valley, was a general,rather than local, phenomenon. To this end, three measurementsites were located spanning the length of the Klang Valley (anurban-industrial region of approximately 3000 km2containing the Malaysian capital, Kuala Lumpur). A fourth sitewas located outside, but adjacent to the Klang Valley, and thefinal site was located 300 km to the southeast, in anurban/industrial region adjacent to Singapore. Annual pHvalues in the range 4.16–4.40 and estimated total depositionfluxes of acidic sulfur and nitrogen species in the range 120–350 meq m-2 yr-1 show all sites to be impactedsignificantly by acidic deposition. Average contributionswere 60% as sulfur species, 40% as nitrogen species. Theresults confirm that potentially significant levels of aciddeposition occur in Malaysia as a regional phenomenonassociated with urban/industrial activities.

Temporal variability of the precipitation chemistry in the forest area of Istanbul, Turkey

The chemical compositions of precipitation show temporal and spatial variability. It is important to determine the temporal variation of the chemical composition of rainwater for estimating the impacts of pollutants on the forest. In this study, the 34 rainwater samples are collected using, for the first time, the specially designed collectors between November 1997 and March 1998 in Istanbul University, Faculty of Forestry at Bahcekoy, Istanbul in Belgrad Forest. The sequentially collected samples are analysed for major ions concentrations and pH estimations. The pH values for all samples vary from 5.1-7.6. In general, the concentration of all rainwater samples decrease with time. Furthermore, it is estimated that the average Ca2+) (1943.0 µeql-1) and SO42- (887.3 µeql-1) concentrations are extremely high during the first ten minutes of the precipitation event.

Chemical composition of rainwater and anthropogenic influences in the Piracicaba River Basin, Southeast Brazil

The influences of different kinds of anthropogenic activities on rainwater chemistry in a tropical area were studied during one uninterrupted year at Piracicaba River Basin (Southeast Brazil). A total of 272 rainwater samples collected continuously from August 1997 to July 1998 at four different sites were analyzed for F −, CH 3COO −, HCOO −, MSA, Cl −, NO 2 −, Br −, NO 3 −, SO 4 2−, C 2O 4 2−, PO 4 3−, Na +, NH 4 +, K +, Mg 2+, Ca 2+, DOC (dissolved organic carbon), DIC (dissolved inorganic carbon), pH and conductivity. The most abundant ion was H + and rain acidity was significant at all sampling sites (average pH of 4.4–4.5). The sources of this free acidity differ among sites and appear to be correlated to the different land-uses. The composition of rainwater appeared to be controlled mostly by three sources: soil dust, sugar cane burning and industrial emissions.