Rainwater Samples Research Articles

A Rapid Derivatization for Quantitation of Perfluorinated Carboxylic Acids from Aqueous Matrices by Gas Chromatography-Mass Spectrometry.

Ultrashort-chain perfluorinated carboxylic acids (PFCAs) are receiving more attention due to their ever-increasing presence in the environment. Methods have been established for the analysis of short- and long-chain PFCAs, while robust quantitation of ultrashort-chain species is scarce. Here, we develop a novel derivatization method using diphenyl diazomethane for quantitation of C2-C14 PFCAs in aqueous matrices. The method is highlighted by rapid completion of derivatization (<1 min) and retention and separation of ultrashort-chain (C2/C3) PFCA derivatives using H2 carrier gas (R > 1.5). A weak anion exchange solid-phase extraction procedure for analyte recovery from representative aqueous samples was developed and validated by spike and recovery from ultrapure water, synthetic ocean water, and simulated denuder extracts used for collecting gaseous PFCAs. Recoveries for PFCAs ranged from 83 to 130% for the majority of analytes and matrices. The instrument detection limits (IDLs) range from 8 to 220 fg per injection, and method detection limits (MDLs) range from 0.06 to 14.6 pg/mL for 500 mL aqueous samples, which are within an order of magnitude to conventional LC-MS/MS methods. The method was applied to the analysis of real samples of tap water, rainwater, ocean water, and annular denuder extracts. The overall method provides a cost-effective alternative to conventional LC-MS/MS methods, overcoming the typical GC-MS drawbacks of high detection limits and long sample preparation times while being able to simultaneously analyze the complete spectrum of environmentally relevant PFCAs.

Theoretical and experimental evidences for the formation of carbonate anion radical (CO3−•) in the atmosphere

Troposphere is the lowest layer where the oxidation reactions responsible for the atmospheric self-purification of contaminants occur, which are initiated mostly by hydroxyl radicals (HO•). In this context, the objective of the present work was to carry out theoretical and experimental studies on the formation of the carbonate anion radical (CO3−•) in the atmosphere and evaluate the spontaneity of chemical reactions that occur at molecular. Experimental tests to evaluate the formation of CO3−• in the atmosphere were conducted using rainwater samples containing 5, 10, and 15 mg L−1 of sodium carbonate, and the addition of methylene blue dye was used to indicate the formation of the CO3−• by monitoring its degradation. Exposure of the samples to solar radiation led to a greater degradation of the dye in rainwater samples with higher concentrations of bicarbonate. The determination of the alkalinity of the samples revealed that the predominant chemical species in the medium was the bicarbonate anion and that the increase in its concentration promotes the formation of CO3−•. As a result of the simulation of the reactions with the radicals •OH, •OOH, and CO3−• at the level of theory MP2/6–311++G (2df,p), it was obtained that the formation of the radical CO3−• is possible (HO• + CO32− → HO− + CO3−• and HCO3− + HO• → H2O + CO3−•). The simulations were carried out in aqueous phase with implicit solvent, in the gas and showed the same trends. Furthermore, the reactions involving CO3−• with atmospheric molecules are spontaneous (ΔrG298 < 0) for electron-rich groups as H2S compounds, indicating that the radical CO3−• can react with some atmospheric molecules, and thus contribute to the atmospheric oxidation mechanisms.

The Chemical Characteristics of Rainwater and Wet Atmospheric Deposition Fluxes at Two Urban Sites and One Rural Site in Côte d’Ivoire

Due to their close relationship with atmospheric chemical composition and global impacts on ecosystems, it is of crucial importance to determine rain chemical composition and quantify wet deposition. In this study, we characterized the chemical composition of precipitation at one rural and two urban sites in Côte d’Ivoire along a south-north transect. Annual and monthly Volume Weighted Mean (VWM) concentration of major ions, as well as wet deposition fluxes in rainwater samples from Abidjan, Korhogo (urban sites), and Lamto (rural site), have been calculated. We also simulated air mass back-trajectories and generated satellite maps of burnt fraction and nitrogen species emissions (NH3, NO2) to better analyze our results. Results show that the dominant ion at both urban sites is Ca2+, whereas NH4+ dominates the chemical content of the Lamto rural site. The analysis of atmospheric sources of influence shows that urban sites rains are characterized by a mixture of terrigenous continental and anthropogenic sources (39–33%), as well as a high marine contribution (34–24%) and a significant nitrogenous contribution (18–25%) mainly associated to fossil fuel from road traffic, domestic and biomass burning sources. At the rural Lamto site, marine, terrigenous, and nitrogenous contributions represent, respectively, 14%, 25%, and 30%. The average pH values are, respectively, 5.76, 5.31, and 5.57 for Abidjan, Lamto, and Korhogo, with a preponderance of mineral acidity contribution at the urban sites, while the organic acidity contribution dominates in Lamto. Neutralization factor (NF) of mineral and organic acids calculations revealed that Ca2+ and NH4+ are the most important neutralizing ions in the rain at all three sites, and we estimated that 79% to 87% of the rain acidity is neutralized by alkaline compounds.

WATER QUALITY ASSESSMENT OF THREE DOMESTIC WATER SOURCES OF AWKA AND NNEWI TOWNS OF ANAMBRA STATE, NIGERIA

The purpose of this study is to determine the quality of water samples from Nnewi and Awka areas and to ascertain their health risk and safety for human consumption. In this study the Canadian Council Water Quality Index [CCME WQI] methodology was used to determine borehole, well, and rainwater samples collected from Awka and Nnewi towns of Anambra. Nine parameters were used for the evaluation, namely: pH, electrical conductivity [EC], nitrates [NO3-], sulphates [SO42-], chlorides [Cl-], Copper [Cu], Iron [Fe], Lead [Pb] and Zinc [Zn] from 60 water samples. CCMEWQI values showed that the water samples were “Good”, therefore making the water samples gotten from these metropolises safe for human consumption.

Comparison of rainwater quality before and during the MCO using chemometric analyses.

This study aimed to classify the spatiotemporal analysis of rainwater quality before and during the Movement Control Order (MCO) implementation due to the COVID-19 pandemic. Chemometric analysis was carried out on rainwater samples collected from 24-gauge stations throughout Malaysia to determine the samples' chemical content, pH, and conductivity. Other than that, hierarchical agglomerative cluster analysis (HACA) and discriminant analysis (DA) were used to classify the quality of rainwater at each location into four clusters, namely good, satisfactory, moderate, and bad clusters. Note that DA was carried out on the predefined clusters. The reduction in acidity levels occurred in 11 stations (46% of overall stations) after the MCO was implemented. Chemical content and ion abundance followed a downward trend, indicating that Cl- and Na+ were the most dominant among the anions and cations. Apart from that, NH4+, Ca2+, NO3-, and SO42- concentrations were evident in areas with significant anthropogenic activity, as there was a difference in the total chemical content in rainwater when compared before and during the MCO. Based on the dataset before the MCO, 75% of gauge stations were in the good cluster, 8.3% in the satisfactory cluster, 12.5% in the moderate cluster, and 4.2% in the bad cluster. Meanwhile, the dataset during the MCO shows that 72.7% of gauge stations were in the good cluster, 9.1% in the satisfactory cluster, 9.1% in the moderate, and 4.5% in the bad cluster. From this study, the chemometric analysis of the year 2020 rainwater chemical composite dataset strongly indicates that reduction of human activities during MCO affected the quality of rainwater.

Hydrochemistry and weathering at Pardo River basin, São Paulo State, Brazil.

This work was conducted at the Pardo River hydrographic basin, which is a federal watershed belonging to the Paranapanema River hydrographic basin (PRHB) in Brazil (São Paulo State and Paraná State). The aim was to realize an integrated hydrochemical and radiometric (U-isotopes and 210Po) approach, highlighting the water/soil-rock and surface water/groundwater interactions, with implications to the weathering processes occurring there. The study area has been often considered one of the best preserved/unpolluted river in São Paulo State, contributing to the water supply of several cities distributed along its banks. However, the results reported here suggest possible lead diffuse pollution caused by the use of phosphate fertilizers in agricultural activities taking place in the basin. The analyzed groundwaters and surface waters tend to be neutral to slightly alkaline (pH of 6.8-7.7), possessing low mineral concentration (total dissolved solids up to 500mg/L). SiO2 is the major dissolved constituent in the waters, while bicarbonate is the dominant anion, and calcium is the preponderant cation. The effects of the weathering of silicates to control the dissolution of constituents in the liquid phase have been identified from some diagrams often utilized in hydrogeochemical studies. Chemical weathering rates have been estimated from hydrochemical data associated to analytical results of the natural uranium isotopes 238U and 234U concerning to samples of rainwater and Pardo River waters. The fluxes in this watershed are permitted to obtain the following rates: 11.43 t/km2 year (sodium), 2.76 t/km2 year (calcium), 3.17 t/km2 year (magnesium), 0.77 t/km2 year (iron), and 8.64 t/km2 year (uranium). This new dataset constitutes valuable information for people engaged on the management of the Pardo River watershed, as well as to researchers interested on comparative studies considering the available data from other basins worldwide.

Patterns of contamination and burden of lead and arsenic in rooftop harvested rainwater collected in Arizona environmental justice communities

As climate change exacerbates water scarcity, rainwater harvesting for household irrigation and gardening becomes an increasingly common practice. However, the use and quality of harvested rainwater are not well studied, and the potential pollutant exposures associated with its use are generally unknown. There are currently no federal standards in the United States to assess metal(loid)s in harvested rainwater. Project Harvest, a community science research project, was created to address this knowledge gap and study the quality of harvested rainwater, primarily used for irrigation, in four environmental justice communities in Arizona, USA. Community scientists collected 577 unique rooftop harvested rainwater samples from 2017 to 2020, which were analyzed for metal(loid)s, where arsenic (As) concentrations ranged from 0.108 to 120 μg L−1 and lead (Pb) concentrations ranged from 0.013 to 350 μg L−1 and compared to relevant federal/state standards/recommendations. Community As and Pb concentrations decreased as: Hayden/Winkelman > Tucson > Globe/Miami > Dewey-Humboldt. Linear mixed models were used to analyze rooftop harvested rainwater data and results indicated that concentrations of As and Pb in the summer monsoon were significantly greater than winter; and contamination was significantly greater closer to extractive industrial sites in three of the four study communities (ASARCO Hayden Plant Superfund Alternative site in Hayden/Winkelman, Davis-Monthan United States Air Force Base in Tucson - Pb only, and Freeport McMoRan Copper and Gold Mine in Globe/Miami). Based on models, infrastructure such as proximity to roadway, roof material, presence of a cistern screen, and first-flush systems were not significant with respect to As and Pb when controlling for relevant spatiotemporal variables; whereas, cistern age was associated with Pb concentrations. These results however, indicate that concentrations vary seasonally and by proximity to industrial activity, not by decisions made regarding collection system infrastructures at the individual home level. This study shows that generally, individuals are not responsible for environmental contamination of rooftop harvested rainwater, rather activities and decisions of government and corporate industries control contaminant release.

Towards a better understanding of flow-related processes in the vertically distributed compartments of karst aquifers by combining natural tracers and stable isotopes

Understanding infiltration pathways throughout the different compartments of karst systems (soil-epikarst-unsaturated zone-saturated zone) is vital to assess recharge processes, vulnerability to pollution, and the general hydrogeological functioning of these kind of aquifers. To gain deeper insight into the soil-water-rock hydrogeochemical processes occurring throughout the vertically hierarchized compartments of the aquifer and to evaluate the applicability of different soil natural parameters as groundwater flow tracers, the present work analyzes the spatial and temporal evolution of total organic carbon -TOC-, intrinsic fluorescence related to organic matter, nitrates, δ13CTDIC, and the values of stable isotopes of δ2H and δ18O from water molecules and at different sampling points in a geologically complex karst aquifer in south Spain (Jarastepar carbonate massif). Over two years, rain and soil water (30 and 60 cm deep) samples were collected simultaneously at an experimental plot along with groundwater from the top of the saturated zone and a base-level spring. Results show that the variation in the concentration of natural soil tracers and the signal of water stable isotopes (δ2H and δ18O) smooth throughout the different compartments of the aquifer, with rapid variations in the unsaturated zone after recharge events and delayed effects in the saturated zone. At the same time, δ13CTDIC and nitrate values rise along the subsurface flow. While the carbon isotope evidences a shorter transit time between recharge areas and the top of the saturated zone than the subsequent path toward the permanent base springs, nitrate evolution is affected by pollution sources near discharge areas, so its applicability is questionable. Finally, organic matter (TOC and intrinsic fluorescence) mineralizes (or degrades) up to 90% from the first centimeters of soil to the permanent basal springs. An exponential decreasing trend defines the relationship between TOC and δ13CTDIC caused by organic matter attenuation along the groundwater flow path, while δ13CTDIC increases because of a higher residence time of water in contact with the host rock. These results, together with previous research based on other natural tracers (chemical, isotopes, and dating tools) and dye tracing experiences, permit to link TOC and δ13CTDIC values with a range of transit times, from hours-days to years-decades. Meanwhile, the attenuation of natural intrinsic fluorescence and TOC signal evidence the filter function of the aquifer from the soil to the saturated zone. All these findings highlight the usefulness of natural fluorescence and, particularly, TOC and δ13CTDIC, as tracers of groundwater flow and hydrogeochemical processes within the different compartments of complex karst aquifers.

Assessing tritium contamination in Thailand's rainwater: A study of environmental monitoring and nuclear surveillance

Tritium, whether naturally occurring or caused by human nuclear activity, can result in a large amount of tritium contamination in the environment, especially in the water cycle, causing a high concentration of tritium in rainfall. The objective of this research was to measure the level of tritium in the environment from rainfall in two different areas as a basis for monitoring tritium contamination in the environment. Rainwater samples were collected in Thailand every 24 h for a period of 1 year during 2021–2022 at the Kasetsart University Station, Sriracha Campus, Chonburi province and at the Mae Hia Agricultural Meteorological Station, Chiang Mai province. The tritium levels were measured in rainwater samples using the electrolytic enrichment method combined with liquid scintillation counting. The chemical composition of the rainwater was analyzed based on ion chromatography. The results (presented with ± combined uncertainty) showed that the tritium content in the rainwater samples at Kasetsart University Station Sriracha Campus was in the range 0.9 ± 0.2–1.6 ± 0.3 TU (0.11 ± 0.02–0.19 ± 0.03 Bq.L−1). The mean concentration was 1.0 ± 0.2 TU (0.12 ± 0.03 Bq.L−1). The most common ions found in the rainwater samples were SO42−, Ca2+, and NO3−, with mean concentrations of 1.52 ± 0.82, 1.08 ± 0.51, and 1.05 ± 0.78 mg.L−1, respectively. The tritium content in rainwater collected from the Mae Hia Agricultural Meteorological Station was in the range 1.6 ± 0.2–4.9 ± 0.4 TU (0.19 ± 0.02–0.58 ± 0.05 Bq.L−1). The mean concentration was 2.4 ± 0.4 TU (0.28 ± 0.05 Bq.L−1). The most common ions found in the rainwater were NO3−, Ca2+, and SO42−, with mean concentrations of 1.21 ± 1.02, 0.67 ± 0.43, and 0.54 ± 0.41 mg.L−1, respectively. The tritium concentration in the rainwater at both stations differed but remained at a natural level (less than 10 TU). There was no correlation between the tritium concentration and the chemical composition of the rainwater. The tritium levels obtained from this study could be used as a basis for reference and monitoring of future environmental changes due to nuclear accidents or activities, both domestically and internationally.

Investigation of the chemical nature of precipitation and source apportionment of its constituents in Tehran metropolis, Iran

Precipitation is a key process for purifying the atmosphere of pollutants. However, precipitation chemistry is also a significant environmental catastrophe on a global scale. Tehran Metropolitan Area, Iran's capital, is one of the world's most polluted cities. Nonetheless, little effort has been paid to determining the chemical composition of precipitation in this polluted metropolis. The chemical components and likely sources of trace metals and water-soluble ions in precipitation samples collected from 2021 to 2022 at an urban location in Tehran, Iran, were investigated in this study. The pH of the rainwater samples varied from 6.330 to 7.940 (mean 7.313, volume weighted mean (VWM) 7.523). The following is the order of the VWM concentration of main ions: Ca2+ > HCO3- > Na+ >SO42- > NH4+ > Cl− > NO3- > Mg2+> K+> F−. Furthermore, we discovered that VWM concentrations for trace elements are modest, with the exception of Sr (39.104 eq L−1). The primary neutralizing species for precipitation acidity were Ca2+ and NH4+. Vertical feature mask (VFM) diagrams derived from cloud-aerosol lidar and infrared pathfinder satellite observation (CALIPSO) track data indicated that polluted dust was the most common pollutant in the Tehran sky that might contribute significantly to the neutralization of precipitation. A study of species concentration ratios in seawater and the earth's crust indicated that virtually all Se, Sr, Zn, Mg2+, NO3-, and SO42- were anthropogenic. While Cl− was largely obtained from sea salt, K+ was obtained from both the earth's crust and the sea, with the earth's crust playing a larger role in K+. The earth's crust, aged sea salt, industry, and combustion processes were all verified as sources of trace metals and water-soluble ions by positive matrix factorization analysis.

Rain Water Harvesting Technology: Drinking water fulfillment and water conservation nearby landfill area

The drawback of groundwater quality occurs due to minimum treatment of waste management in the landfill. The research objectives are to know the groundwater quality around the landfill study site, rainwater potential for drinking water purposes, and decreasing runoff due to rainwater harvesting technology implementation. The well water samples were collected from eight wells surrounding the landfill. Rainwater samples were collected from rainwater harvesting technology installation. Water quality parameters consist of total coliform, pH, and Total Dissolved Solids (TDS). Water conservation was observed by infiltration and precipitation. Total coliforms of well water are higher than rainwater. Furthermore, based on acidity and TDS values, well water is higher (pH 6.5-8.5 and TDS 188.8 + 128.7 ppm, respectively) than rainwater (pH 6.1 + 0.2 and TDS 8.4 + 1.4 ppm, respectively). Based on three parameters, rainwater is more proper for drinking water than well water in the study site. Rainwater harvesting technology is able to reduce runoff by 58.42% with the rainwater catchment area around 7,095 m2. Waste management in landfills should concern with groundwater pollution. Rainwater harvesting technology is a potential solution for drinking water supply in water crisis areas.

Geochemical investigation on the implications of fluid origin, subsurface processes and recharge on the Tangkuban Perahu geothermal conceptual model

Tangkuban Perahu and nearby volcano-hosted geothermal prospects are believed to be important for future power generation in West Java, Indonesia. Recharge areas of these prospects and geothermal fluid evolution are not yet fully understood. This study aims to describe the fluid origin, processes, and evolution of geothermal fluids concerning the recharge and the conceptual model of the Tangkuban Perahu Geothermal Systems (TPGS). Sampling and analyses of geothermal waters, rainwater, and gases collected in fumaroles and other manifestations were implemented in this study. Isotopic results of δ18O and δ2H collected from thermal and rainwater indicate deep-circulating meteoric origin, at an infiltration altitude range between 753 and 850 m in low terrain. Meanwhile, the high-standing terrain indicates the recharge zone to be within the wall of the Sunda Caldera and mountain slopes. Chondrite normalized patterns reveal an overall flat trendline that suggests the enrichment of Lower Rare Earth Elements (LREEs) in the central part of Tangkuban Perahu which is derived from the magmatic influx. The non-atmospheric gases origin was diagnosed by the lower N2/Ar (≤ 38) and is characterized by meteoric origin. The positive δ18O shifts from Ciater (CT), Batu Gede (BG), and Domas Crater (KwD) geothermal waters samples comparatively to the local meteoric lines are influenced by the interaction with wall rocks or magmatic influx. In these geothermal systems, the meteoric water infiltrated to the depth is heated, mixed with near-surface water, and followed by partial discharge as thermal springs along the faults. The resultant Tangkuban Perahu conceptual model has six distinct reservoirs with five geothermal systems hosted in the sedimentary (northern parts) and volcanic rock composition in the central and southern parts.

Gas Flaring, and Its Environmental Impact in Ekpan Community, Delta State, Nigeria

In the Ekpan settlement of the Uvwie local government area, Delta state, Nigeria, a study on gas flaring and its effects on the environment was carried out. It was found that hazardous gases have been released into the environment because of air pollution caused by the combustion of methane and other hazardous flue gases during the manufacturing and processing of hydrocarbons. Industrial flue gas flare-ups cause several problems and are harmful to public health and the environment. This study investigated the pH of rainwater, as well as air pollutants (NO₂, SO₂, CO₂, CO, and suspended particle matter). During the dry and wet seasons, samples of air and rainwater were collected at different distances around exposure sites, and they were then examined using established techniques for the air contaminants. Descriptive statistical tools such as mean and standard deviation were used to analyze the variance and degree of effect of pollutants. The obtained results showed that the mean CO₂ concentrations in the dry and wet seasons were, respectively, 0.036 ppm and 0.26 ppm and that the pH of rainwater in the wet season was 6.82, both of which were within the safe limits, indicating that there were little to no negative effects on the environment. However, the average concentrations of suspended particulate matter in dry and wet seasons respectively were 7.92 mg/m₃ and 5.95 mg/m3, NO₂ was 0.15ppm and 0.10ppm, SO₂ was 0.72ppm and 0.10ppm, CO was 11.20ppm and 10.24ppm, and CO₂ 0.036ppm and 0.26ppm. The pH of rainwater was 6.02 for the dry season which exceeded the acceptable ambient air limits set by the DPR (2002) and FMENV (1991), while during the wet season, the pH was 6.82. This study suggested that the activity of continuous gas flaring is one of the main causes of high concentrations of these air pollutants within the examined community. The findings further suggested that the numerous environmental, socioeconomic, and political issues within Epkan were linked to the effects of gas flaring. This study suggests that the challenges caused by gas flares for the Ekpan community are good enough grounds to stop the practice of gas flaring in the area and the government needs to enact strict legislation with penalties for defaulters. The study finally recommended that flared gas could be refined and reused.

The Stable Isotopes Approach as Tracers to Investigate the Origin of Groundwater In The Unconfined Aquifer of Denpasar, Bali

Groundwater plays an elemental role in the supply of water for numerous purposes, so the use of groundwater must also pay attention to the balance and preservation of the resource itself. Knowing the origin of the groundwater and the recharge area on an aquifer is essential to determine the conservation model. The purpose of this research is to determine the Denpasar Meteoric Water Line (DMWL), the recharge area, and the origin of groundwater in the unconfined aquifer of Denpasar. The determination of the number and location of samples, both rainwater samples, and groundwater samples, using a purposive sampling approach. A total of 5 samples of rainwater and 18 samples of groundwater were taken at several locations in the Denpasar area. The stable isotopes of δ18O and δ2H were carried out using laser spectrometry Picarro L2130-i. This research shows the Denpasar LMWL is δD = 8.5839 x δ18O + 19.876; from the distribution of oxygen-18 isotope, the low 18O value is dominated in the North and Northeast areas, so here this area can be delineated as the potential recharge area; and based on the isotope ratio, groundwater in the unconfined aquifer of Denpasar can be divided into three geneses groups: (a) Groundwater Genesis-A and B groups represent groundwater systems that come from direct rainfall as well as local recharge with low (depleted) to moderate δ18O and δ2H isotope ratios and groundwater groups Genesis-C, which has high (enriched) δ18O and δ2H isotope ratios, is located below the slope of the DMWL.

Temporal variations of precipitation driven by local meteorological parameters in southwest China: Insights from 9 years of continuous hydro-meteorological and isotope observations

Study regionNorthwest of Guangxi Province, southwest China. Study focusKnowing the role of isotopes in precipitation can improve understanding of climate change and eco-hydrological processes in complex critical-zone systems. However, knowledge of the influence of local meteorological factors on variations of precipitation isotopes remains limited as high-resolution rainwater sampling is lacking. New hydrological insights for the regionThe temporal characteristics (intra-annual, seasonal, and monthly scales) of precipitation were analyzed using daily precipitation isotopes data from 2011 to 2020 and event-resolving data from 2019 to 2020 at Huanjiang in southwest China. The boosted regression tree model was used to explore the relationship between local meteorological factors and δ18O values. On an intra-annual scale, δ18O, δD, and d-excess values exhibited significant sinusoidal fluctuation, being lower and higher during the wet and dry seasons respectively. Temperature is the most sensitive meteorological factor to monsoon climate response. On the seasonal scale, ET0 explains 37.5% of isotopic variations in the dry season, thus indicating that the influence of evaporation on the rainwater isotopes variation should be considered. The “amount effect” of rainwater isotopes was clearly shown on the monthly scale. However, precipitation isotopes did not follow the “amount effect” on an inter-event scale, which can be explained by large-scale convection activity. These findings can improve interpretations of isotopic variations in precipitation in humid subtropical climate zones.

Freshwater Uptake of Mangrove Growing in an Extremely Arid Area

This study evaluated the freshwater use of two mangrove species (R. mucronate: Rhizophora mucronata and A. marina: Avicennia marina) growing in a coastal area of Djibouti City and on Moucha Island in Djibouti. We accomplished this by comparing hydrogen and oxygen stable isotope ratios (δ2H and δ18O) in the body water with those of creek water, soil water, groundwater, and rainwater samples. Line-conditioned excess (lc-excess) was calculated for the δ2H and δ18O values of the groundwater and rainwater samples. Although two regression lines were drawn using the δ2H and δ18O values of the plant body water as well as the environmental water, no significant differences were found, suggesting that the effects of isotope fractionation due to evaporation in all the samples were almost similar. Comparison of lc-excess and δ18O suggested that the body water from the two mangrove species growing on Moucha Is. were strongly influenced by seawater, but contained some freshwater sources other than the seawater, the soil water, and the creek water. It was also found that Avicennia marina growing in the coastal area was strongly influenced by groundwater. The origin of the freshwater absorbed by the mangroves on the island was not clear, but it could be groundwater recharged in a faraway place.

Kajian Uji Kualitas Sumber Air untuk Pemenuhan Kebutuhan Air Bersih di Daerah Rawa yang Berkelanjutan

Siak Regency consists of plains and hills with an average soil composition consisting of podzolic red yellow rocks and alluvium and organosol soil and humus gley in the form of swamps or wet gley. United States Department of Agriculture (USDA) that Podsolic Red Yellow (PMK) soil is a soil formed due to too low temperature and very high rainfall and is an ancient mineral soil type with a reddish or yellowish color. This podzolic soil color indicates relatively low soil productivity due to leaching. While the red and yellow soil colors are caused by rusty iron and lumps of aluminum that decompose and undergo weathering. Clay minerals in this soil are dominated by compounds containing silicon, oxygen, and some metals, which have implications for water quality. The purpose of this research is to test water quality to support the fulfillment of sustainable clean water needs in the Swamp Area in Rempak Village, Siak District, Siak Regency, Riau Provonce. The approach method used is Permenkes No. 492/Menkes/IV/2010.The data needed for this research is to use primary data by taking samples of rainwater, well water, and raw water from the Siak river by researchers directly on March 16, 2022. The main results of the research stated that the quality of rainwater was ranked first to support the policies of the National Development Planning Agency towards a just and prosperous Indonesia in 2045 which has mandated the importance of water security to support strategic sectors, disaster prevention, and improvement of community welfare through construction of rainwater harvesting buildings.

Atmospheric wet deposition of mercury in urban Jinan, eastern China: Speciation, scavenging process and potential sources

Understanding the speciation and related influence factors of Hg in wet deposition is important to predict the fate and transport of mercury in the atmosphere. In this study, event-based samples of rainwater were collected for one year in Jinan, a northern city in eastern China. The volume-weighted mean concentration of total mercury (THg) in rainwater was 34.8 ng L−1, comparable to levels in some inland cities in China and were significantly higher than those in North America, Korea and Japan. Most of the Hg in rainwater was associated with particulates, accounted for 15.2–92.9% of THg with a mean of 66.9%, which might be attributed to the scavenging effects of high particulate-bound mercury concentrations in ambient air in urban Jinan. Dissolved mercury (DHg) accounted for 33.1% of THg, in which Hg(OH)2, HgClOH, HgCl2 and Hg(NH3)22+ are the dominant species based on the chemical equilibrium modeling simulations. THg concentrations in rainwater decreased as the rainfall amount increased owing to the dilution effect and 5 mm rainfall might be a threshold for the full wash-out capability of atmospheric Hg. For a continuous rain event, the proportion of DHg in THg could increase from 7.1% to 84.8% with the rainfall processing, especially for the species of HgClOH and HgCl2 under the influence of rainwater pH. Positive matrix factorization (PMF) analysis suggested that the major sources of Hg in rainwater were combustion emissions, marine sources, industrial emissions, as well as complexation process, which contributed to 51.4%, 24.7%, 12.2%, and 11.7% of the THg, respectively. For the specific species, the main sources varied with different Hg species, in which combustion emissions contributed one third to one half of each species sum to particulate mercury (PHg), HgClOH, HgCl2, HgBrOH and HgBrCl followed by marine sources and industrial emissions. Cluster analysis of backward trajectories revealed that polluted air masses, transported from southeast Shandong, Anhui and Jiangsu Provinces, as well as Beijing-Tianjin-Hebei region, contributed to high Hg concentration in rainwater in Jinan.

Use of rain water in floor washing and garden irrigation: a case study

The socioeconomic context brought by the COVID-19 pandemic and the war in Ukraine, caused a crisis in the world economy. Faced with this situation of inflation and the rise of the dollar, access to basic items such as water and cooking gas has become an obstacle for the needy population. There are alternatives to overcome water scarcity, and one of them is the use of water harvesting systems with low-cost technologies, which facilitate replication in environments that do not have a water distribution network, allowing the economically disadvantaged population access the water. This work analyzes the use of rainwater in garden irrigation and floor washing in a public building. The case study was carried out at the Civil Court and Consumer Relations Court in Camaragibe, PE. The rainfall index and the history of water consumption were analyzed, as well as the analysis of rainwater in the study region. Reservoir simulations and economic analysis were performed using the NETUNO software. The economic simulation resulted in the value of R$3,000.00 (three thousand reais), and a payback time of 5 years. After analyzing the simulations and the results of the rainwater samples, as well as complying with the requirements of the ABNT 15527/2019 standard, it can be inferred that the implementation of rainwater harvesting for non-potable use is feasible.Keywords: Harvesting rainwater. Sustainability. Low cost technology.

Effect of the first-flush phenomenon on the quantification of microplastics in rainwater

Precipitation of airborne microplastics (MPs) by rainfall is one of the major transport pathways of MPs from land-to-marine. While most studies examining wet precipitation of MPs collect surface runoffs, direct investigations of MPs in rainwater are hardly reported. In this study, high-frequency and direct rainwater sampling methodology considering the first-flush effect was demonstrated. The variations in MP abundance were evaluated by the inlet size of rainwater collector, time, and duration of sampling. As a result, a stable abundance of MPs was obtained when samplings were conducted at the same time and duration even with different collectors. On the other hand, the abundance increased as much as 4.5 times in samples collected at different times due to the first-flush effect of rainfall. Thus, our methodology that presents MPs concentration versus time curves based on high-frequency sampling would be helpful for easy comparison between similar rainfall studies.