Composition Of Rainwater Research Articles

Carbon and oxygen isotope characteristics of the Clydach Valley Subgroup, Courceyan, South Wales‐Mendip shelf, UK

AbstractThe Clydach Valley Subgroup (Courceyan) records a dip section through an Early Carboniferous shallow marine, carbonate shelf and consists of three oolitic formations separated by paludal/peritidal units with abundant evidence of subaerial exposure in proximal areas. The lower part correlates with the Kinderhookian–Osagean Boundary Excursion, with allochem data indicating a minimum δ13C value for marine carbonate of +4.5‰, with associated δ18O of −4.6‰. Marine carbonate δ13C and δ18O values of +2‰ and −2‰, respectively, were estimated for the younger part. Allochem isotopic data yield a well‐defined mixing line consistent with stabilisation in meteoric water at varied water: rock ratios, the degree of stabilisation increasing up‐dip and up‐stratigraphy. Two distinct diagenetic styles closely correlate with evidence for the presence (Diagenetic Regime 1) or absence (Diagenetic Regime 2) of subaerial exposure, non‐ferroan and ferroan calcite cement dominating respectively. Five cement zones (Zones 2–6) defined by iron content occur in Diagenetic Regime 1, irrespective of formation, indicating a similar sequence of palaeohydrological changes affected repeated depositional cycles. Zones 3–5 are considered meteoric based on their isotopic composition (δ18O: −5.8 to −11.1‰ and δ13C: −3.7 to −6.2‰) and form distinct clusters dependent on zone, age and location. Pedogenic carbonates and meteoric cements record a long term increase in meteoric δ18O values: −7.8‰ during the Kinderhookian–Osagean Boundary Excursion, −6.9‰ during diagenesis of the upper part of the subgroup and −6.3‰ associated with initial deposition of the overlying Llanelly Formation. This is consistent with global sea water trends, but an element of climate change cannot be ruled out. Increases in cement δ18O values as meteoric systems become established (Zone 3–4) indicate repeated short term variation in rainwater composition probably driven by climate change, but also suggests a link between climate and the depositional cycle.

Возможности повторного использования дождевых сточных вод

The problems of the efficiency of the implementation of sustainable development Programs in terms of the conservation of water resources in urbanized areas are aimed at finding alternative solutions with the inclusion of innovative technologies and the search for optimal criteria for controlling water use conditions. It should be noted that there is insufficient knowledge and elaboration of technologies for the use of rain water resources. The purpose of the research is to develop and supplement the standardized requirements governing the possibility of reusing rainwater with the justification of the criteria for choosing systems for their collection and treatment. There are discrepancies and methodically insufficient elaboration of the problem of substantiating the criteria for choosing rain water collection and treatment systems, taking into account current trends in technology development, it is necessary to add standardized requirements regulating the mechanism of their reuse. To solve the problem, it is proposed to conduct studies clarifying the qualitative composition of surface wastewater, for which laboratory sampling of rainwater from various catchment surfaces was carried out. The results of chemical analyses showed a difference in the characteristics of rainwater collected from roofs, roads and courtyards. Based on the qualitative composition of rainwater, it was found that rainwater collected from roofs has the least pollution. Technological features of rainwater collection and treatme nt for their further reuse are described. It is proposed to create an accumulating reservoir, the replenishment of which will be carried out as it is used, taking into account the calculated values of the basic techniques. A technological scheme for the treatment of rainwater collected from roofs has been developed, the simplicity and cheapness of the proposed technology is noted.

Optimization of a Laboratory Rainfall Simulator to Be Representative of Natural Rainfall

The importance of understanding the effects of rainfall on different materials over time makes it essential to carry out controlled tests to reduce analysis time. Rainfall simulators have been in use for decades and have been implemented as technology and knowledge of the physical behavior of water advanced. There are two main types of rainfall simulators: gravity simulators and pressure simulators. In the former, the drop velocity is normally smaller than the terminal velocity reached by natural droplets; in the latter, the drop size is too small to be representative and has far more speed than the natural speed for those sizes. To solve this problem, a simulator has been developed where the terminal velocity of the raindrops is reached and the drop size can be varied by different nozzles of variable sizes, adapting it to the conditions of a given region. In this study, conditions similar to the rainfall conditions of the city of León have been achieved. This paper presents the design of a rainfall simulator that recreates different rainfall conditions and rainwater composition and its calibration process.

Chemometric and risk assessment of nitrogen composition of atmospheric rainwater from diverse surfaces in Rivers State, Nigeria.

Organic and inorganic nitrogen ions in the environment play important role across environmental matrices. Rainwater samples collected from ambient and different roofing surfaces (zinc, aluminium, asbestos and stone-coated roofing sheets) from selected locations at Ogale, Rumuodomaya/Rumuodome, Diobu and Chokocho within Rivers State, Niger Delta, Nigeria, from April to June, July to August and September to October depicting three regiments of early, mid and late rains. The samples were analysed for Kjeldahl nitrogen, ammonium, nitrate and nitrite using APHA methodology. Quantitative assessment showed that Kjeldahl nitrogen were in range of 0.11 to 28.05mg/L; ammonium 0.50 to 20.22mg/L, nitrate from 0.12 to 22.69mg/L and nitrite from 0.15 to 3.90mg/L. Parameters decreased from early to late rain, which can be attributed to rain dilution factor potential, wind pattern and emission from anthropogenic sources that influenced the rainwater quality across surfaces. Nitrogen results showed that dry and wet deposition has great impact; atmospheric aerosols and biogeochemical interactions can affect water quality. Monthly variation showed that Ogale had high regression compared to other locations due to close proximity to oil and gas emission and marine contribution. Neutralization factor showed that nitrate-nitrite compounds have strong correlation with ammonium ion. Non-carcinogenic risk assessment using US EPA model showed hazard index less than one (1), thus no associated health effect of nitrate and nitrite in rainwater. In conclusion, it is evident that nitrate/nitrite levels and other nitrogen derivatives in rainwater in crude oil-producing Niger Delta and its continuous consumption can cause negative health outcome.

Chemical composition and source apportionment of rainwater over Bangladesh during the monsoon

Chemical composition and source apportionment of rainwater over Bangladesh during the monsoon

Chemometric approach to evaluate the chemical behavior of rainwater at high altitude in Shaune Garang catchment, Western Himalaya

The present research has been performed to analyze the chemical behavior of rainwater of the Shaune Garang catchment (32.19° N, 78.20° E) in the Baspa basin, located at a high elevation (4221 m above mean sea level) in the Himachal Himalaya, India. During the study period, sixteen rainwater samples were collected from the Shaune Garang catchment at five different sites. The volume-weighted mean (VWM) pH value of rainwater ranged between 4.59 and 6.73, with an average value of 5.47 ± 0.69, indicating the alkaline nature of rainfall. The total ionic strength in the rainwater ranged from 113.4 to 263.3 µeq/l with an average value of 169.1 ± 40.4 µeq/l. The major dominant cations were Ca2+ (43.10%) and Na+ (31.97%) and anions were Cl− (37.68%), SO42− (28.71%) and NO3− (23.85%) in rainwater. The ionic ratios were calculated among all the ions. The fraction of (NO3− +Cl−) with SO42− was measured as 2.3, which specifies sour faces of rainwater due to HNO3, H2SO4, and HCl. A multivariate statistical assessment of rainwater chemistry through Principal Component Analysis (PCA) shows the significance of four factors controlling 78.37% of the total variance, including four-component (PC1 explained 27.89%, PC2 explained 24.98%, PC3 explained 14.64%, PC4 explained 10.85%). However, the individual contribution of Factor 1(PC1) explains 27.89% of the total variance (78.37%) and displays a strong optimistic loading for Ca2+ and Cl−. Further, high loading of Ca2+ and NO3− and moderate loading of SO42− signify the contribution of burning fossil fuel and soil dust. Anthropogenic and natural pollutants influence the composition of rainwater in the pristine Himalayas due to local and long-distance transportation. The study area receives precipitation from the West and North-West, transporting dust and fossil fuel emissions from the Thar Desert and Northwestern countries.

Depth distribution and chemistry of salts as factors controlling tafoni and honeycombs development

Salts play a pivotal role in the processes forming tafoni and honeycombs but only few studies have focused on their areal and depth distribution. An X-ray diffraction, rock leachates chemistry, and evaporation front depth were combined to get a deeper insight into factors controlling salt composition and distribution. Five sites representing various lithological and/or climate conditions were studied. The data show that salt composition is a result of the interaction between chemical compositions of rainwater and lithology. Gypsum was found to be a major salt on all sites with halite dominating in arid sites. On humid sites the high relative air humidity prevents its precipitation. Gypsum and epsomite dominate also on sites where the rock contains a considerable amount of pyrite. Alum-(K) occurs in quartz sandstones when affected by acid rain. Some ions probably occur in residual brines, rather than precipitated salts (CaCl in arid or NaCl in humid sites). On arid sites, the salt content in the tafoni backwalls is 4–20 times higher than in outer walls and rapidly decreases with depth which is consistent with shallow evaporation front in backwalls. The low salt content in the outer walls reflects the dilution effect of surface runoff after rains and the infiltration of water through the outer walls toward depth. In two humid sites, on the contrary, no differences were found between the salt content of the backwalls and the outer walls. At one site the data shows that the whole surface of tafoni serves as the salt precipitation zone and tafoni are thus recently degrading. The honeycomb site differs from all tafoni sites since the honeycombs are mostly protected from rain runoff, which prevents the washing-out of salts even from the outer walls.

Wet season chemical composition of atmospheric wet deposition at Cape Point

The measurement of precipitation chemistry enables the assessment of the temporal and spatial evolution of the chemical composition of the atmosphere associated with atmospheric physical and chemical mechanisms. The aims of this study were to report the chemical composition of rainwater collected at a marine environment, i.e. the Cape Point Global Atmosphere Watch (CPT GAW) station from 2004 to 2012. As expected, the volume weighted mean (VWM) concentrations of Na+ (298.64 μEq.L-1) and Cl- (354.18 μEq.L-1) were significantly higher compared to the VWM concentrations of other ionic species, as well as compared to the VWM concentrations thereof at the sites in the South African interior. The average pH of rainwater was slightly lower than the pH of unpolluted rainwater, mainly due to NO3- associated with the occasional influence of the Cape Town metropole. In contrast to the sites situated in the north-eastern South African interior, where anthropogenic SO42- was the major constituent in rainwater, SO42- at CPT GAW was entirely associated with marine air with no anthropogenic contribution. It was also indicated that 94% of the chemical content at CPT GAW can be attributed to the marine source.

Wet Scavenging in Removing Chemical Compositions and Aerosols: A Case Study Over the Lake Urmia

AbstractLake Urmia, NW Iran, and S Caucasus region, has lost approximately three‐fourth of its water volume resulting in increased exposure of lacustrine deposits. Therefore, the role of Lake Urmia desiccated saline lands on local aerosols and rainwater compositions is still vague. This study investigates the temporal and seasonal patterns of rainwater chemistry from January 2018 to June 2018 (six months) in 13 stations throughout the Lake Urmia basin. The samples collected were analyzed using triple quadrupole inductively coupled plasma mass spectrometry (ICP‐QQQ) and ion chromatography (IC) to measure elemental and ionic concentrations. Then, the Hybrid Single‐Particle Lagrangian Integrated Trajectory model (HYSPLIT) was applied to identify the pathway and contribution of emissions. The results depict that the concentration of elemental and ionic components over different parts of the Lake Urmia basin are significantly different. West and north directions have the highest concentrations of marine ions associated with fewer toxic elements. In contrast, the east and south directions show a high concentration of heavy metal elements and ions. The high level of heavy and toxic elements at the east and south directions indicates that local anthropogenic sources are more influential. The seasonal and monthly variabilities of chemical compositions depict that the highest concentration of Na+, Mg2+, Ca2+, K+, Cl−, Br−, NO3−, Al, Cr, Mn, Fe, and Co were in the spring season and SO42−, NH4+ and NO2− were highest in winter. Seasonal variation for MSA, organic acids (i.e., Pyruvate, Adipate, and Oxalate), Ni, Cu, Zn, V, and Ti were not apparent. Cluster‐mean HYSPLIT backward trajectories results show the most dominant air mass sectors are from W (a: Iraq, Syria, and Arabian deserts; b: Mediterranean Sea; and c: KSA) and NE (the Caspian Sea and its vicinity), contributed to almost 65% and 22%, respectively. These air masses bring a significant quantity of crustal and marine aerosols, respectively. It is inferred that the Lake Urmia dried‐up lakebeds have less impact on the contribution of emissions across the region.

Nd and Sr Isotopes and REE Investigation in Tropical Weathering Profiles of Amazon Region

The exceptional development of lateritic profiles make the Amazon one of the best places to conduct a refined study on the effects of long-term tropical climate on the Earth's surface rocks. Concentrations of Nd and Sr isotopes, as well as rare earth elements (REE), Sr, and other trace elements were determined in six profiles in order to shed new light into element behavior and into the processes controlling the geochemistry and the transfer of these elements among the different compartments of the critical zone. Our investigation indicates natural isotope regional pulse transformations in the Oxisol at the top of all profiles. The ƐNd(t=0) values of the parent rock, mottled horizon, and lateritic duricrust are radiogenic similar to the Amazon craton signature. The thick Oxisol has ƐNd(t=0) values which are much more radiogenic and less variable, whereas it has Zr, Th, Y, and REE in higher concentrations. These issues highlight a complex process for the Nd system, and the following possibilities are proposed to explain this behavior: formation of authigenic cerianite and/or kaolinite, penetration of low-temperature weathering solutions along zircon fractures, and some vegetation uptake. These possibilities allow keeping the more radiogenic Nd isotopes, whereas the less radiogenic Nd is released especially in the Oxisol after REE mineral(s) weathering. The Sr system contrary to that of Nd became less radiogenic along the profiles and relatively to the parent rocks content, because nearly all Sr was removed after K-Rb feldspar and mica weathering. However, a mixture return of less radiogenic Sr from plant, biogenic aerosol, and rainwater may have helped let the weathering profiles become less radiogenic. These characteristics let the Oxisol even less Sr radiogenic but still permitting to identify the general parent rocks signature. In contrast, Nd is highly fractionated in the Oxisol relative to the parent rock. Thus, the REE and Sr behavior, similar in the six profiles, does not necessarily reflect only the parent rock geochemistry, but it also depends on the multiple surficial processes typical of the critical zone: weathering, pedogenesis, plant root activity, and rainwater composition which change the inherited primary minerals isotope signatures.

The Absolute Age and Origin of the Giant Gypsum Geode of Pulpí (Almería, SE Spain)

Subaqueous gypsum (CaSO4·2H2O) crystals are relatively common in epithermal systems where sulfide ore deposits are present. The Giant Geode of Pulpí (Almería, SE Spain) hosts some of the largest (up to 2 m in length) subaqueous gypsum crystals discovered to date. Here, we present the first U-series ages of its crystals and reconstruct the oxygen and hydrogen isotopic composition (δ18O and δ2H) of the Pulpí paleo-aquifer from which the crystals formed by using stable isotopes of gypsum hydration water. We successfully dated the onset of gypsum precipitation in the Geode at 164 ± 15 ka. However, the extremely low U concentration (11 ppb) and relatively high detrital Th content (230Th/232Th 3.2) hinder accurate dating other gypsum samples. The δ18O and δD values of the paleo-aquifer during the growth of the crystals aligned with the local meteoric water line, suggesting that the sulfate-enriched mother solution consisted of meteoric water that recharged the aquifer during that period. The mean isotopic composition of the Pulpí paleo-aquifer (δ18O = −6.5 ± 0.1‰ and δ2H = −42.3 ± 0.5‰) during the formation of the crystals was similar to the current groundwater in this area (δ18O = −6.1 ± 0.8‰, δ2H = −42 ± 6‰). The isotopic differences observed in samples collected from distinct locations and in individual crystals were probably related to changes in the isotopic composition of the aquifer, as a consequence of varying climate that impacted on the isotopic composition of rainwater during thousands of years in this region. Our results indicated that subaqueous selenite crystals may be useful for paleo-hydrological reconstructions. However, improving the current analytical techniques for dating gypsum with low U concentrations will be essential to obtain accurate and reliable records from Quaternary gypsum cave crystals in the future.

Hydrochemistry of atmospheric precipitation over an urban station in the peninsular India: Assessment of the long-term data

Long-term data on precipitation chemistry is crucial for the formulation of climatology of major acidifying as well as neutralizing components and their trends over the years. Rain water samples were collected during the monsoon season (June to September) for three decades (1981–2016) at Pune, an urban global atmospheric watch (GAW) station in the peninsular India. The long-term volume weighted mean (VWM) pH was 5.91 ± 0.57. The pH showed a significantly decreasing trend with about 9% acidic occurrences. Temporal variation of annual mean nss SO42- and NO3-showed an increasing trend whereas, a decreasing trend of NH4+and an increasing trend of Ca 2+was observed. The lowest mean wet deposition flux during the monsoon season over the entire period was observed for NH4+and highest was for NO3-. Source apportionment for ionic components through Positive Matrix Factorization (PMF) indicated the factor comprising of crustal source contributed 35% to the total ionic concentration followed by the sea salt ions that comprised of 33%. The anthropogenic sources mainly comprising of industrial, vehicular, agricultural and residential activities also contributed significantly (25%) indicating the importance of man-made emissions in driving the rain water composition and the associated pH around the region.

Influence of Typhoons on Chemical Makeup of Rainwater in Zhanjiang, China

Typhoons are extreme weather events with substantial effects on ambient air. However, whether typhoons of different intensities have the same effects on the chemical composition of rainwater is unclear. Therefore, 4 years of rainwater sampling and an analysis of the ionic composition (Cl–, Ca2+, Na+, SO42–, Mg2+, F–, and K+) of rainwater were conducted in Zhanjiang, a city on the southern tip of mainland China. The ionic composition varied seasonally, being high in dry seasons whereas low in wet seasons; ion levels were controlled by rainfall dilution effects rather than by the monsoon transition. Source determination demonstrated that the marine influences in the dry and wet seasons were similar, further indicating the limited impact of the monsoon climate on the ionic species’ seasonal patterns. The heavy rain and strong wind (> 47.4 m s–1) brought by a super typhoon led to an increase in ionic species carried from continental sources into ambient air, and such species were then captured by precipitation. The weak winds (10.71–12.84 m s–1) brought by weak typhoons failed to blow such ions into the air, but rainfall dilution still occurred and was dependent upon rainfall amount. Our results suggest that strong typhoons can increase ion concentrations in rainwater, whereas weak typhoons reduce such concentrations. The results provide new insight into the relationship between air quality and typhoons.

Chemical Characteristics and Trends of Indian Summer Monsoon Rainfall: A Review

The Indian summer monsoon (ISM) regulates the pace of life for billions of people in the Indian subcontinent by driving the agriculture and Gross Domestic Product of the region. The chemical composition of ISM is influenced by pollutant type, meteorology, and topography. As a result, the chemical makeup of rainwater varies greatly across places. The current review article highlights the variations and trends of the principal chemical constituents of rainwater (Na+, K+, Ca2+, Mg2+, NH4+, NO3–, SO42– and Cl–) across six homogeneous Indian monsoon regions: Central Northeast, Hilly, Northwest, Northeast, Peninsular and West Central region. Average rainwater pH ranged from 5.31 to 6.70 in these six regions. The incidence of acidic rain events at three separate locations in the Peninsular region suggests a significant impact of anthropogenic emissions. The chemical composition of rainwater in all these regions varied considerably and seemed to form a regional pattern. The majority of the ions in rainwater were highest in the Northwest while lowest in the Peninsular region. Cl– had a significant correlation with Na+ and NH4+ in the Hilly region, and with Na+ and Mg2+ in the West Central region suggesting it is sourced from both marine and anthropogenic sources. The soil Enrichment Factor relative to Ca2+ demonstrated that soil has a significant effect on rainwater composition. Ca2+ was determined to be the most abundant neutralizing ion in all the regions. Furthermore, the synthesis of rainwater chemistry reveals a strong relationship with dominant interannual climate variability El Niño Southern Oscillation with significantly higher concentrations of Na+, K+, Ca2+, Cl– and SO4– in rainwater during El Niño year compared to La Niña year.

Monitoring Rainwater Properties and Outdoor Particulate Matter in a Former Steel Manufacturing City in Romania

Wet deposition is influencing air quality because air pollutants are washed away from the surrounding air. Consequently, particulate matter and associated compounds are transported in the rainwater and enter into soil, surface waters, and groundwater. Nonpoint sources of heavy metals from stormwater runoff have increased in urban areas due to industrialization and the increasing impervious surfaces. In this work, we present an assessment of the rainwater composition regarding the nutrients and other physicochemical characteristics measured in three locations selected in Targoviste city, Romania, a city that had a specialized steel factory and important metallurgical facilities. The rainwater was collected using three PALMEX rain samplers and then was transferred to high-density polyethylene bottles and analyzed using ICP-MS. PM2.5 concentrations were also monitored continuously using optical monitors calibrated using a gravimetric sampler. A detailed analysis of the heavy metals content in rainwater and PM was presented for the pollution episodes occurring in October and November 2019. Backward trajectories were computed using the HYSPLIT model for these periods. The results showed that the PM2.5 ranged from 11.1 to 24.1 μg/m3 in 2019, while the heavy metals in collected rainwater were (µg L−1): 0.25 (Cd) − CV = 26.5%, 0.10 (Co) − CV = 58.1%, 1.77 (Cr) − CV = 24.3%, 377.37 (Ni) − CV = 27.9%, 0.67 (Pb) − CV = 74.3%, and 846.5 (Zn) − CV = 20.6%. Overall, Ni, Pb, Cr, and V had significant correlations between the concentrations from rainwater and PM. Negative associations were found between precipitation events and heavy metals both from rainwater and PM, but only a few showed statistical significance. However, this could explain the “washing” effect of the rain on the heavy metals from PM2.5. The potential sources of nitrogen in the rainwater collected in Targoviste could be from burning fossil fuels and the soils, including both biological processes and fertilization resulting from the intensive agriculture in the piedmont plain in which the city is located. Based on the results, rainwater monitoring can constitute a reliable method for air quality characterization. Additional research is required to better understand seasonality and sources of heterogeneity regarding the associations between PM and rainwater composition.

Chemical composition of rainwater at an urban and two rural stations in the west of Iran, Hamedan

Chemical composition of rainwater at an urban and two rural stations in the west of Iran, Hamedan

Subpollen particle release from different species of the invasive allergenic genus Ambrosia: the effect of rainwater composition and wind speed

Allergen-containing subpollen particles (SPPs) are micrometric or sub-micrometric particles (0.12–5 µm) released from pollen. They are able to reach the lower airways, causing allergenic reactions. SPP release occurs through the pore of intact grains or by rupture of the whole grain. In this paper the results of two laboratory experiments investigating the dynamics of SPP release for three alien species of Ambrosia genus are shown. Rainwater composition and wind speed were considered, by simulating different conditions, in accordance with a fully orthogonal experimental design. The principle response variable was the total percentage of SPPs-releasing pollen grains; also the percentage of intact grains releasing SPPs through the pore and of broken SPPs-releasing grains were considered. Both osmotic and mechanical shock caused the discharge of SPPs but different results were observed. The highest number of releasing grains was recorded in case of acid solution and 20 knots wind speed. Moreover, wind and rainfalls caused SPPs release through different mechanisms. Wind mainly provoked a mechanical shock leading to grain rupture, whereas rainfall caused mainly SPPs release through the pore of intact grains. Comparing species, the effect of wind and at least in some cases also that of rainwater appeared to be less relevant for Ambrosia trifida than for Ambrosia psilostachya and Ambrosia artemisiifolia. The obtained results suggest a species-specific response of Ambrosia species to wind speed and rainwater that lead to a different release of SPPs and then to a species-specific impact on allergy according to the characteristics of their growth environment.

Multiple isotopic tracing for sulfate and base cation sources of precipitation in Hangzhou city, Southeast China: Insights for rainwater acidification mechanism

Acid deposition has been regarded as a serious factor in the deteriorative water environment and ecosystems. Despite the powerful acid emission control measures have been implemented by the Chinese government, many areas (especially Southeast China) are still suffering from acid deposition. The chemical and isotopic (δ34S and 87Sr/86Sr) compositions of rainwater in Hangzhou, a typical megacity in Southeast China with serious acid rain problem, for one year were studied with the aim to better constrain potential sources and explore the causes of rainwater acidification. Most rainwater samples were acidic, with a VWM pH value of 4.65. SO42− was the dominant anion and the main acid ion in rainwater. Sulfur isotope and the quantity equilibrium model revealed that sea salt, crustal, biogenic, and anthropogenic sulfur represented 2.3%, 0.1%, 16.7%, and 80.8% of the SO42− source in rainwater, respectively. The back trajectory and strontium isotopes indicated that the base cations (BCs) in rainwater originated mainly from anthropogenic sources. The relatively low neutralizing capacity caused by limited BCs input and emission control measures undermines some efforts to reduce rainwater acidity. This case study demonstrated that a valuable tool to probe the source of acid rain and unravel the mechanism of rainwater acidification can be provided by multiple lines of evidence, including rainwater chemical compositions, stable sulfur isotopes, and stable strontium isotopes.

Study on Acidity and Neutralizing Ability of Ions in the Chemical Composition of Rainwater

The acidity in rainwater is mainly controlled by the presence of H2SO4, HNO3 in combination with the ability to neutralize cations in rainwater. pH is an important value in the evaluation of acidity in rainwater. The research used a series of rainwater quality monitoring data from 2005 to 2018 in Vietnam. The research showed that the average pH distribution at 23 stations ranged from 5.83 ± 0.62. The rains with pH <5.6 appear in all years at the research stations. Considering the ability of acid neutralizing to various ions shows that Ca2+ is the main contributor to acid neutralization processes in rainwater, followed by Mg2 +, NH4+, and K+. While Ca2+ always play the highest acid neutralizing role at all stations; Depending on each station, Mg2+ and NH4+ ions play a role in neutralizing acidity in rainwater. The research also shows a match between the trend of H+ concentration and the tendency of cations to contribute to acid neutralization in rainwater.

Interlinkages Between Total Nitrogen and DOC Levels at an Urban Site of Saharsa District of Bihar (India)

Nitrogen is an element essential for building fundamental blocks of life. When present in excess amount in air, it causes adverse effects for the environment and human health.Different air pollutants when scavenged through rains are deposited on the surface. The chemical composition of rain water is an indicator of the levels of different air pollutants in the region. The present study reports the concentrations of Dissolved Organic Carbon (DOC) and the reactive nitrogen species (NO3- and NH4+) in rain water at an urban site located in the Saharsa district of Bihar. The sampling was carried out during July 2018 to October 2018.Total 18 samples were collected during this period. Results showed that the concentration of NO3- was considerably higher (2.91 mg/L)ranging from 0.26 to 11.84 mg/L than the NH4+(0.84 mg/L) ranging from 0.00 to 3.2 mg/L.The pH value in the samples ranged from 5.50 to 7.68 with a mean value of 6.52.The DOC in rain water has been estimated by using the Shimadzu TOC analyzer. Apart from DOC, total carbon (TC), total nitrogen (TN) & inorganic carbon (IC) have also been also analyzed by Shimadzu TOC analyzer. The results showed that both anthropogenic and natural sources contributed to the dissolved organic carbon (DOC) in rain water. The linkages between the sources and the transformations of gaseous NH3 with DOC have been established considering the fact that most of TN is represented by NH3.Airmass back trajectory analysis showed that the site has trans-boundary source influence from Bay of Bengal and Bangladesh. The study suggests that there is need of continuous monitoring of these parameters in air in order to notice any impact on human health, soil and vegetation.