Rainwater Samples Research Articles

Influence of anthropogenic activities and loess dusts on the rainwater hydrochemistry in the Chinese Loess Plateau

Rainwater hydrochemistry is an important indicator for tracing anthropogenic input on air quality. As the fastest economically developing city in the northwestern China and the Chinese Loess Plateau, rainwater chemistry, sources of dissolved solutes, and the influence of loess dust on rainwater chemistry in Xi'an city is unclear. Inorganic ions, δD and δ18O of two years' rainwater samples were measured to decipher the above issues. Rainwater samples were weakly alkaline (pH = 7.2) with the mean total dissolved solids (TDS) values of 43 mg/L. NH4+ and Ca2+ dominated in the cations and SO42− and NO3− dominated in the anions. The wet deposition of sulfur (S) and nitrogen (N) was 70.9 ± 67 mg·(m2·month)−1 and 244.8 ± 270.9 mg·(m2·month)−1, respectively. The meteoric water line in Xi'an was δD = 7.29δ18O+3.72 (R2 = 0.99). δD, δ18O, and d-excess analysis indicated the influence of evaporation on the dissolved solutes in rainwater, especially in the dry season. Rainwater acidity in the Xi'an city was mainly neutralized by Ca2+ and NH4+, and the neutralization ability in Xi'an city is higher than the southern China cities. Correlation analysis (CA), positive matrix factorization (PMF), and the backward air masses trajectory model identified high NH4+ and Ca2+ in rainwater were mainly originated from local agricultural activities and loess dust, while NO3− and SO42− were associated with local coal combustion and vehicle exhaust sources. High inputs of dusts and coal combustion in spring and winter resulted in elevated values of pH and major ions in Xi'an. Due to the air pollution control policy, air quality in Xi'an is getting better in recent years. Our study highlights the influence of anthropogenic activities and loess dusts on the rainwater hydrochemistry in Xi'an and provides important dataset for air pollution control for other cities in semi-arid and arid regions.

Rainwater extracting characteristics and its potential impact on DBPs generation: A case study

Frequent extreme precipitation events due to global warming can lead to large amounts of pollutants entering source water bodies via surface runoff and wet deposition, thus posing a threat to water supply security. In order to better understand the source characteristics and leaching mechanisms of rainwater dissolved organic matter (DOM), as well as its disinfection by-products formation potential (DBPsFP) during disinfection processes, rainwater samples were collected and extracting experiments were conducted. Three components were identified in rainwater through Parallel factor (PARAFAC) analysis, which were microbial humic-like component C1 (63.1 %), protein (tryptophan-like) component C2 (28.9 %), marine or terrestrial humic-like component C3 (8.1 %). The average molecular weight of rainwater fractions was ordered: hydrophobic neutral (HON) < hydrophobic bases (HOB) < hydrophobic acidic (HOA) < hydrophilic (HIS). The HOA and HON fractions of rainwater were the dominant precursors of trihalomethanes (THMs), while the rainwater HON fraction and hydrophilic fraction were the main precursor of haloacetic acids (HAAs) and trihloroacetonitrile (TCAN), respectively. Subsoil extracts had a higher concentration of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) than topsoil extracts. Partial least squares path modeling (PLS-PM) demonstrated that the extraction temperature was the dominant factor affecting the abundance of DOM in the topsoil extracts (R2 = 0.28), while the extraction time accounted more for the abundance of fluorescence substance and physicochemical indices in the subsoil extracts (R2 = 0.23 and 0.32, respectively). These results provide key information for controlling the impacts of global warming, in particular the risk of water sources being heavily contaminated by request rainfalls.

Groundwater recharge estimation using chloride mass balance method on the southern slope of Merapi Volcano, Indonesia

Groundwater is a main resource for the majority of Indonesian people as a source of clean water to meet their daily needs. The increase in groundwater use is unavoidable due to increasing development in Indonesia, especially in Yogyakarta. Groundwater recharge is important in the hydrological cycle to meet groundwater needs. Therefore, this study aims to estimate groundwater recharge by the chloride mass balance (CMB) method on the southern slope of Merapi Volcano in Yogyakarta, Indonesia. This research was conducted in the rainy and dry seasons from August 2022 until January 2023. This research collects annual rainfall near the study area from the Meteorology, Climatology, and Geophysics Agency (BMKG) Yogyakarta station, monthly data collected from eighteen samples of groundwater station, and monthly data collected from fifteen samples of rainwater in the study area. The chemical content of groundwater and rainwater samples is analyzed using argentometry to obtain chloride concentration. The result of annual rainfall in the study area is 3,603.878 mm/year. The average chloride concentration in rainwater is 1.1 mg/L, while the average chloride concentration in groundwater is 8.015 mg/L. The CMB method calculation showed that the recharge in the study area ranges from 171.65 to 1,711.29 mm/year. The groundwater recharge has a positive correlation with elevation and rainfall. High groundwater recharge is also found in the northern area due to fractured lava aquifer.

Anions Cations Balance in Rainwater of Lanka, Mirzamurad and Babatpur, Varanasi

The analysis of anions cations balance in rainwater samples, were carried out in the Department of Soil Science and Agricultural Chemistry Laboratory at the Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during 2015. The rainwater samples of three different location viz. Lanka, Mirzamurad and Babatpur places of BHU, Varanasi, which are relatively free from industrial pollution were examined during south-west monsoon period (July to September) in Varanasi using standaralize selection and analytical methods for evaluation of anions cations balance of rainwater. It was revealed from the Tables 1-3 that the total mineralization varied from 53.65 to 171.38 mg L-1 in Lanka, 25.49 to 153.55 mg L-1 in Mirzamurad and 73.32 to 286 mg L-1 in Babatpur, respectively. In an average total mineralization was highest in Babatpur followed by Lanka and Mirzamurad.

Microclimatic Variation in Miri Region (NW Borneo): Inference from Rainfall and Temperature Trends, Isotopic Signature and Air Mass Movement

Trend analysis is frequently utilised to identify the changes in meteorological and hydrologic time series data, such as rainfall and temperature. The variations in the intensity, rainfall pattern and temperature have gradually changed globally. Hence, in this study, an attempt was made to analyse the decadal rainfall and surface air temperature data to understand the microclimatic variations in the Miri coastal region of NW Borneo. A data series of records for daily total rainfall amount and daily surface temperature of 11 years from 2010 to 2021 was studied and analysed. In addition, representative rainwater and groundwater samples were collected and analysed for hydrochemical parameters and oxygen and hydrogen isotopes. A detailed literature review was carried out on rainfall patterns in Malaysia, which was used for the comparative study. Interpretation of results shows that the northeast monsoon (NEM) contributed a higher total rainfall rate with lower daily mean surface air temperature over the years compared to the southwest monsoon (SWM). The recorded data for rainfall amounts in SWM for the month of May, July, August and September were higher, particularly for the years 2010 and 2020. During NEM, a higher rainfall amount was recorded in the month of January for several years. February month has always been among the driest month in NEM, and September has been the wettest month throughout the year during SWM. The isotopic values of rainwater indicate a similar moisture source to the regional precipitation trend. Groundwater isotopes reveal the low water-rock ratio of retrograde exchange between water and primary silicate minerals in the aquifer. The moisture source of the precipitation was contributed from both oceanic and continent, affecting the rainfall intensity in this region. This study is a crucial outcome to determine the potential impacts of microclimatic variations on the rainfall patterns in the Miri coastal region.

Canopy Leaching Rather than Desorption of PM2.5 From Leaves Is the Dominant Source of Throughfall Dissolved Organic Carbon in Forest

AbstractDissolved organic carbon (DOC) in throughfall plays a vital role in providing carbon and energy to organisms in forests. We utilized carbon isotope analysis to allocate the sources of throughfall DOC, including leaching from plant tissues, PM2.5 deposition on plant foliage, and precipitation. Rainwater, PM2.5, and throughfall samples were collected from pine and oak forests between March and November 2021. The mean concentration of throughfall DOC was 7.9 mg L−1, approximately six times higher than that of rainfall. The mean Δ14C of throughfall DOC was −38.2‰, ∼200‰ higher than that of rainwater or PM2.5. Mass balance estimates revealed that canopy leaching contributed to ∼83% of throughfall DOC, while desorption of PM2.5 and rainwater accounted for only ∼3% and ∼14% of throughfall DOC, respectively. These results clearly highlight canopy leaching as the primary source of carbon input to the forest floor, with a relatively minor contribution from PM2.5 desorption on leaves.

Health and exposure risk assessment of heavy metals in rainwater samples from selected locations in Rivers State, Nigeria

Abstract Rainwater has being getting popularity in use due to lack of portable water sources in Nigeria. The study seeks to evaluate the health and exposure risk assessment of heavy metals from the usage of rainwater from inhabitants of four oil producing area of Rivers State, Nigeria. A total of 32 rainwater samples were collected from different sampling surfaces (ambient, zinc, aluminium, asbestos and stone-coated) to analyse for arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), lead (Pb) and zinc (Zn) using inductively coupled plasma – optical emission spectrophotometer. Analysed concentration (mg/L) showed varying results across different sampling surfaces converted to average concentration (mg/kg) was below WHO/FAO recommended guideline with no issue associated. Health and Exposure risk assessment were performed on analysed results from rainwater samples as non-carcinogenic risk assessment showed that HI value is less than 1.0 indicating no risk to population who consumes rainwater across different roofing surfaces in Rivers state. Carcinogenic risk assessment showed that chromium-VI were found to be the highest contributor to cancer risk across all sampling surfaces. Special treatment and regulations should be taken into consideration especially on stone-coated roof before administering to children, as they are prone to health issues due to developing immunity compared to adults.

Determination of the radiation dose from radon ingestion and inhalation in different types of drinking water samples collected from Bethlehem province –Palestine

The objective of this study is to investigate the levels of radon gas and increase public awareness of its hazards to health in Bethlehem governorate- Palestine. The concentrations of radon-222 and radium- 226 in 79 different types of water samples were measured. The average values of radon and radium concentrations in tap water, rainwater, groundwater, and mineral water samples were 0.93 Bq/ℓ and 45.5 Bq/kg, 1.01 Bq/ℓ and 49.3 Bq/kg, 1.21 Bq/ℓ and 59.3 Bq/kg, and 0.60 Bq/ℓ and 29.2 Bq/kg, respectively. All the measured radon concentrations in the collected samples were within the limit of 11 Bq/ℓ established by UNSCEAR in 1982. The annual effective doses for ingestion and inhalation due to radon in water were calculated for adults, children, and infants using parameters introduced by UNSCEAR in 2000. The results show that there is no significant risk to public health from radon inhalation or ingestion through drinking water in the study region.

Characteristics of hydrochemical and stable isotopes in the Upper and Middle Reaches of the Yarlung Tsangpo River

There have been few studies on the spatiotemporal variation of the hydrochemistry and stable isotopes characteristics in the upper and middle reaches of the Yarlung Tsangpo River owing to its high elevation and alpine climate, and the primary controlling mechanisms have yet to be clarified. Statistical analysis, a Piper diagram, Gibbs diagrams, ion correlation analysis, and other methods were integrated to analyze water samples from the main stream and tributaries of the Yarlung Tsangpo River together with rainwater samples from certain areas obtained in May 2020. And both the formation mechanism of the hydrochemistry and the process of chemical weathering were explored. The results revealed that river water in the basin was of HCO3−–SO42−–Ca2+ type (i.e., weakly alkaline), evaporite weathering had little impact on chemical weathering in the upper and middle reaches of the Yarlung Tsangpo River, and chemical weathering in the basin was controlled jointly by weathering of silicate rock and carbonate rock. Overall, the mean value of deuterium excess of the samples from the upper and middle reaches of the Yarlung Tsangpo River was 7.22‰, i.e., lower than the global mean of precipitation (10‰), indicating that the sampled water was subject to evaporation enrichment to some extent. Owing to the unique climatic and geographic conditions of the Qinghai–Tibet Plateau, the upper and middle reaches of the Yarlung Tsangpo River were also affected by water–rock interaction (chemical weathering and physical erosion). In addition, the relationship of stable isotopes between rainwater and riverwater also suggested that precipitation is an important source for river water in the upper and middle reaches of the Yarlung Tsangpo River.

Evaluation of the Effects of Heavy Metals on Sediments and Rainwater Samples Due to Gas Flaring in the South Eastern Nigeria

This study evaluates the concentrations of heavy metals in sediment and rainwater samples of Ibeno, south eastern Nigeria due to gas flaring. Surface sediment samples were collected randomly in six different sites during the dry season in the intertidal zone at extremely low tide from the flare point to a distance of about 250m away from the flare site. Rainwater samples were collected with the use of pre-clean basins at an open space in three selected communities of Ibeno and were transferred into different sterilized plastic rubbers with their labels. These samples were transported to the laboratory for analysis of heavy metals concentrations using a particle induced x-ray emission (PIXE) technique. Heavy metals such as Titanium (Ti), Chromium (Cr), Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Rubidium (Rb), Strontium (Sr), Zirconium (Zr) and Lead (Pb) were analyzed in sediments while Vanadium (V), Arsenic (As), Nickel (Ni), Lead (Pb), Iron (Fe), Copper (Cu), Zinc (Zn), Chromium (Cr), Manganese (Mn) and Cadmium (Cd) were obtained in rainwater. The concentrations of Iron (Fe) in sediments are higher at the study area than every other elements but Manganese (Mn) poses more negative effects than others. The four pollution indices such as enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF) and pollution load index (PLI) were employed to assess the contamination status of heavy metals in sediment samples of the study area. The results revealed the elemental trend to be in descending order in each area of this study, which followed the sequence Mn&gt; Zn&gt; Pb&gt; Cu&gt; Fe&gt; Sr&gt; Rb&gt; Cr&gt; Ti &gt;Zr, while PLI revealed the extent of pollution in each site which ranged from 1.44 to 1.94. Most of the heavy metals concentrations in sediments such as Mn, Zn, Pb, Cu and Fe were far above the permissible limits, while in rainwater samples Pb, Cd, Ni, Fe and Mn were far above the permissible limits by WHO, 2008 and NSDWQ, 2007. This revealed that the rainwater in the study area were not free from toxicity and are unfit for drinking. Analysis of multi-variant statistics such as Pearson’s correlation coefficient and cluster analysis were also applied to ascertain the relationship and sources of investigated heavy metals. Both positive and negative correlations were observed among some heavy metals at 0.01 and 0.05 levels, while the cluster analysis revealed four main clusters. The study revealed that the ecosystems in the studied areas were vulnerable to bioaccumulation of heavy metals in that soil which could be of hazard effect to the ecosystem.

Temporal and spatial shifts in the chemical composition of urban coastal rainwaters of Kuwait: The role of air mass trajectory and meteorological variables

The rainwater chemistry encompasses the signatures of geogenic and anthropogenic processes along the regional air mass movement apart from the local sources. The predominance of dust events and anthropogenic emissions in arid regions facilitate new particle formation. Further, rain events of different seasons depict moisture sources from diverse regions reflecting variation in the regional geochemistry with respect to seasons. Hence, to characterize the geochemical composition of rainwater, the study has focused on an integrated approach by considering regional transport, meteorological components and possible local sources. A total of 74 rainwater samples were collected from 27 rain events in 2018, 2019, and 2022, representing urban coastal areas of Kuwait predominantly of Ca-SO4-HCO3 type. The average pH and electrical conductivity of the rainwater were 7.18 and 140 μS/cm, respectively. The sea salt fractions calculated relative to Kuwait seawater ranged from 25.6 to >100 %, with higher values attributed to anthropogenic sources. Sea salt fraction, ion ratios, principal component analysis and factor scores revealed the terrestrial and anthropogenic sources apart from marine contributions. In addition, new particle formation and aerosols contributed to the rainwater chemistry involving SOx, NOx, and photochemical reactions during higher relative humidity and lesser wind speed. The HYSPLIT reflected that the moisture sources were largely from western regions of the study area, and those of December and January events had long-distance travel across the Azores high originating from northeast America. The trajectories of the November events are observed to originate from the Caspian/Black Sea region in the northeastern part of Kuwait with a relatively shorter distance of travel. The rainfall samples had higher ionic concentrations, and saturated with aragonite and calcite minerals in a few locations specifically after the dust events, while the subsequent rain events were less polluted.

Assessment of Heavy Metals in Rainwater from Metropolis and Suburbs, Lagos State, Nigeria

Heavy metal pollution poses a threat to rainwater which serves as a major alternative source for water for developing cities like Lagos. In the investigated of heavy metal in rainwater, 176 rainwater samples collected directly from the sky were analyzed from 2018 to 2019 during periods of light rainfall (Oct-Nov) and heavy rainfall (April-July). The pH&gt; 5.6 indicated alkalinity. Light rainfall period average value 7.33 and heavy rainfall period 7.4.The MATLAB 7th degree polynomial regression described the relationship between dependent and independent variables for the pollutants. The correlation coefficient, R2 verified that the MATLAB models could accurately predict and forecast. Analysis of Variance (ANOVA) showed p&lt;0.05 for Cadmium (Cd), Copper (Cu), Zinc (Zn), Iron (Fe) and Nickel (Ni), indicating that the probability that rainfall affected their concentration levels was high. The GIS Inverse Distance Weighted (IDW) pollution models revealed that the pollutants were present in the atmosphere throughout the year. It portrayed industrialized areas as the more affected areas thereby identifying anthropogenic activities as the main cause of these pollutants. During heavy rainfall periods hot spots appeared for Cd, Cu, Zn and Ni. In addition, Cd, Cu, Zn, Pb, and Ni were present in high concentration in the rainwater from suburb areas during periods of heavy rainfall. The concentration of heavy metals found in the rainwater follows the order: Fe&gt;Zn&gt;Ni&gt;Cu&gt;Cd&gt;Pb. Cd and Pb exceeded WHO standards. Therefore there is need for rainwater treatment and monitoring by Government Agencies and parastatals to ensure public health and safety.

Chemical composition of monsoon bulk precipitation in the Salalah area, Oman

Precipitation chemistry data provide important information for environmental studies on large-scale element cycling and anthropogenic impacts on our atmosphere, but also for hydrochemical models and groundwater recharge estimations via the Chloride Mass Balance method. Such recharge data play a crucial role in groundwater management, particularly in (semi-)arid areas. Unfortunately, precipitation analyses are often scarce in such regions. This also applies to the Arabian Peninsula, including southern Oman. To overcome this lack of rain chemistry data, we developed a strategy for automatic weekly bulk precipitation sampling, using recently designed automatic rainwater samplers. The integral samples were gathered along an elevation gradient from the Salalah coast to the Dhofar mountains during the Indian Ocean Monsoon seasons 2017 and 2018.Our major ion analyses of the rainwater samples revealed considerable temporal and spatial heterogeneity, in terms of ion proportions and absolute concentrations. Samples from the coast were relatively salty (EC mostly >3000 μS cm−1) and rich in Na+ and Cl−, reflecting small rain amounts and a sea spray effect. Further inland, solute concentrations were lower, partly due to more precipitation, and ions such as Ca2+ and SO42− gained importance, probably due to calcite and gypsum dust. This pattern reflects the interplay between solute availability (influenced by regional geology, wind direction at different altitudes, and wind speed) and precipitation amounts. Cl−/Br− ratios were fairly uniform and scattered around the seawater value. Combining ion concentrations and rain amounts yielded bulk depositions that showed an erratic pattern along the elevation gradient, i.e., depositions did not decrease steadily in inland direction, as one may assume. This suggests that the occasionally reported approach of collecting a few opportunistic grab samples at a single site is unlikely to yield data that are representative for a larger coastal study area.

The Potential of Rainwater Harvesting as an Alternative Source of Clean Water at the Faculty of Science and Technology UIN Walisongo Semarang

Rainwater harvesting (RWH) is the process of directly preventing rainwater runoff and introducing rainwater into a reservoir for daily use. RWH can also be an alternative for providing clean water in the UIN Walisongo campus area. With the construction of new buildings and the addition of the number of students each year, the need for clean water is also increasing. This study aims to determine the quality of rainwater in the FST Building and to analyse the potential of rainwater harvesting as an alternative source of clean water in the FST Building of UIN Walisongo Semarang. This study examined rainwater quality as a clean water alternative in the Faculty of Science and Technology building. The location for taking rainwater samples was carried out at the FST Campus 3 Building. Laboratory tests for rainwater quality were carried out at the Centre for Standardisation and Industrial Pollution Prevention Services (BBSPJPPI) in Semarang. The rainwater samples analyzed met the clean water quality standards based on Ministry of Health Regulation No. 32 of 2017 concerning Environmental Health Quality Standards and Water Health Requirements for Sanitary Hygiene, Swimming Pools, Solus Per Aqua, and Public Baths, except for the organic matter parameter (KMnO4), according to laboratory tests.

Microplastics and anthropogenic debris in rainwater from Bahia Blanca, Argentina

Concern about atmospheric microplastic (MP) contamination has increased in recent years. This study assessed the abundance of airborne anthropogenic particles, including MPs, deposited in rainfall in Bahia Blanca, southwest Buenos Aires, Argentina. Rainwater samples were collected monthly from March to December 2021 using an active wet-only collector consisting of a glass funnel and a PVC pipe that is only open during rain events. Results obtained show that all rain samples contained anthropogenic debris. The term “anthropogenic debris” is used to refer to the total number of particles as not all the particles found could be determined as plastic. Among all the samples, an average deposition of 77 ± 29 items (anthropogenic debris) m−2d−1 was found. The highest deposition was observed in November (148 items m−2d−1) while the lowest was found in March (46 items m−2d−1). Anthropogenic debris ranged in size from 0.1 mm to 3.87 mm with the most abundant particles being smaller than 1 mm (77.8%). The dominant form of particles found were fibers (95%), followed by fragments (3.1%). Blue color predominated (37.2%) in the total number of samples, followed by light blue (23.3%) and black (21.7%). Further, small particles (<2 mm), apparently composed of mineral material and plastic fibers, were recognized. The chemical composition of suspected MPs was examined by Raman microscopy. The analysis of μ-Raman spectra confirmed the presence of polystyrene, polyethylene terephthalate, and polyethylene vinyl acetate fibers and provided evidence of fibers containing industrial additives such as indigo dye. This is the first assessment of MP pollution in rain in Argentina.

Water budget of tropical volcanic lakes in center‐north Cameroon: Reconciling the stable isotope and chloride mass balance

AbstractThe Cameroon volcanic line (CVL) hosts numerous volcanic lakes whose internal processes and hydrological functioning remain poorly documented. A detailed understanding of these hydro‐systems is however essential, both for the consideration of these lakes as sentinels of the regional hydro‐climatic changes and for the calibration of palaeoenvironmental proxies. Here, we present a hydrological and geochemical investigation of five of these lakes (Mbalang, Tabere, Tizon, Gegouba and Baledjam) around Ngaoundere on the Adamawa Plateau, based on repeated sampling of water profiles and monthly monitoring of rain and lake water samples over two seasonal cycles. We show that each of these throughflow lakes bears a distinct geochemical and isotopic signature, despite quite similar morphometric characteristics and a common climatic regime, due to varying contribution of the watersheds to the water‐mass balance and different partitioning between evaporation (E) and outflow (Inflow minus E). We use these differences as a benchmark for a sensitivity analysis of the classical budget equations of conservative tracers. The results demonstrate that to reconcile chloride and stable isotope data with the standard single‐box steady state model would require unusual values of the physical parameters of Craig and Gordon's equation such as the n.θ term that would have to be significantly lower than its usual value (n.θ = 0.5). We also show that the data can be simulated more easily by including the inflow from the watershed while assuming that transpiration exceeds evaporation for this compartment. Using this conceptualization of the throughflow lakes, we were able to constrain the different fluxes. Transpiration from the watershed and evaporation from the lake are on the same order of magnitude, or slightly in favour of transpiration. While providing evaporation and transpiration rates which are in general in the right order of magnitude, the system of equations remains underdetermined at this stage. Only direct measurements of the isotopic composition of the atmosphere, possible by laser mass spectrometry, would allow to reduce the range of under‐determination of this problem.

Heavy and less common metals in rainwater and the kinetics of the oxidation of hydrogen sulfide by oxygen in rainwater medium.

As a sequel to our recent study on the oxidation by O2, i. e., autoxidation of dissolved hydrogen sulfide, H2S, in aqueous medium, we present here the results of a similar study in rain water medium. The rainwater sampling was done sequentially for four years (2016-2019). In all 67 samples of rainwater were collected on event basis during monsoon period (June-October) in and around the Campus of University of Rajasthan, Jaipur (26°50̛ N-75°52̛ E), which is situated in a semi-arid region adjacent to the Thar Desert in the North-Western part of the India having an annual average rainfall of 54cm. ICP-MS technique was used in the analysis of rainwater and more than 30 metals were detected, which included transition metals, rare earths, less common metals. Beryllium, vanadium, silver, selenium, manganese, cerium, gallium, yttrium, barium, cesium, copper, rubidium, arsenic, lanthanum, cadmium, lead, uranium and bismuth were common to all rain water samples.H2S oxidation by dissolved oxygen was studied in rainwater as well as in laboratory water media for comparison. The kinetics rate law was: -d[O2]/dt = k1K1[H+][S][O2]t/( [H+]2 + K1[H+] + K1K2), where K1 is first dissociation constant of H2S and k1 is the rate constant for the dominant reaction step:HS- + O2 → products.

Microbiological Assessment of Rainwater and Air Quality of Some Areas in Port Harcourt

The microbiological quality of Rainwater and air of the market, hospital, and residential area was evaluated. Roof-harvested and direct rainwater samples were collected from the three aforementioned locations. The air quality was investigated using the plate sedimentation method. Culture-based techniques were used for the enumeration and isolation of microorganisms in water samples, while the identities were confirmed using morphological, microscopic, and biochemical tests. The range of the total heterotrophic bacterial counts (THBC) of rainwater was 1.2±7.1x106 to 6.1±1.1 x106 cfu/ml, total coliform count (TCC) ranged between 8.0±0.00 x103 to 30.5 ±2.1 x103 cfu/ml, faecal coliform counts (FCC) ranged between 1.0±0.00×103 to 6.0±0.00×103 cfu/ml, fungal counts ranged from 2.0±0.00x103 to 11.0±0.00x103 cfu/ml. The THB, TCC, and FCC of the air samples, ranged between 0.04±0.02 to 0.13±0.04 cfu/min-m2, 0.01±0.00to 0.03±0.00 cfu/min-m2, and 0.01±0.00 to 0.02±0.00 cfu/min-m2, respectively. There was a significant difference (P≤ 0.05) in the total heterotrophic bacterial load of the roof-harvested rainwater and the direct rainwater of the residential area, roof-harvested and direct rainwater of the hospital. Statistically, there was a significant difference (P≤ 0.05) in the total coliform counts of the water with the coliform counts of the roof-harvested rainwater of the market being significantly higher than the coliform counts recorded in other locations. Seven bacterial genera belonging to Micrococcus sp, Staphylococcus, Escherichia coli, Proteus sp, Pseudomonas sp, Enterobacter sp, and Bacillus sp were isolated. The fungal isolates were Candida sp, Mucor sp, Rhizopus sp, Penicillium sp, Aspergillus niger, and Aspergillus flavus. The results showed that rainwater is not fit for consumption due to its components and can cause harm to individuals if consumed without treatment. proper treatment is recommended before consumption. The results also showed that the microbiological quality of the air samples was influenced by their environment.

Assessing the impact of rainwater harvesting infrastructure and gardening trends on microbial indicator organism presence in harvested rainwater and garden soils.

To assess the microbial water quality of harvested rainwater infrastructure used to supplement household water uses for homegrown produce. Using a co-created community science methodology, between 2017 and 2020, a total of 587 harvested rainwater samples and 147 garden soil samples irrigated with harvested rainwater were collected from four Arizona communities and analyzed for coliform, Escherichia coli, and/or Salmonella. Participants also completed a home description survey regarding their home and surrounding area, water harvesting infrastructure, and gardening habits. Chi-Square tests revealed that the quality of harvested rainwater is affected by proximity to a waste disposal or incineration facility, animal presence, cistern treatment, and cistern age (P<0.05), while soil samples were associated with community (P<0.05). Coliform and E. coli concentrations in both sample types were greater in the monsoon season.

Metabolically active bacteria detected with click chemistry in low organic matter rainwater.

Rain contains encapsulated bacteria that can be transported over vast distances during relatively short periods of time. However, the ecological significance of bacteria in "precontact" rainwater-rainwater prior to contact with non-atmospheric surfaces-remains relatively undefined given the methodological challenges of studying low-abundance microbes in a natural assemblage. Here, we implement single-cell "click" chemistry in a novel application to detect the protein synthesis of bacteria in precontact rainwater samples as a measure of metabolic activity. Using epifluorescence microscopy, we find approximately 103-104 bacteria cells mL-1 with up to 7.2% of the observed cells actively synthesizing protein. Additionally, our measurement of less than 30 μM total organic carbon in the samples show that some rainwater bacteria can metabolize substrates in very low organic matter conditions, comparable to extremophiles in the deep ocean. Overall, our results raise new questions for the field of rainwater microbiology and may help inform efforts to develop quantitative microbial risk assessments for the appropriate use of harvested rainwater.