The risk of cross-border pollution and the influence of regional climate on the rainwater chemistry in the Southern Carpathians, Romania

Characteristics and sources of chemical composition in precipitation on the Loess Plateau of China

Knowing the sources of precipitation chemical composition is essential to understand the biogeochemical cycle and control air pollution. Despite this issue has been directly investigated with precipitation ion contents, the effects of water vapor transport have not been fully considered. Taking the Loess Plateau of China (LPC) as an example study area, this study established nine precipitation monitoring sites considering the variability in topography and rainfall amounts, and collected 435 precipitation samples during 2020-2022 to measure the chemical composition. The correlation analysis, positive matrix factorization model and backward trajectory model were combined to analyze the characteristics, sources and vapor transport effects of precipitation chemical composition. Seasonally, except for NH4+, the concentration of other ions in the dry season was significantly higher than that in the rainy season. Spatially, the concentrations of Ca2+, Na+, K+, SO42- and NO3- peaked in the Mu Us Sandy Land and industrial areas, while the high level of NH4+ was concentrated in the agricultural areas. The source apportionment found that the primary source of precipitation ions was crust (33 %), followed by coal combustion/vehicle (30 %), aged sea salt (21 %) and agriculture (16 %). The trajectory analysis showed that water vapor paths significantly varied with the seasons, but were primarily dominated by the northwestern air mass with proportions of >40 %. The dust aerosols transported by the northwestern air mass were the main contributor to crust-source precipitation ions. The eastern and southeastern air masses transported anthropogenic pollutants to the LPC, and the southeastern air mass also carried sea-salt precipitation ions. This study provides a framework to incorporate hydrochemical method with vapor source identification method for precipitation chemical source identification, and the results can be a theoretical basis for the treatment of atmospheric environmental problems.

Assessment of heavy metals in rainfall as an indicator of air pollution from Erbil Steel Factory in Iraq

The goal of the current study is to evaluate the heavy metal rainfall contamination in the vicinity brought on by the Erbil Steel Factory in Iraq during the study period. The study's findings revealed the concentration of all studied heavy metals in the precipitation near and around the factory is significantly higher than that of the rural area of Barzan village which is used as a control site. The average concentration of the metals is in descending order manganese (Mn) > lead (Pb) > iron (Fe) > arsenic (As) > cobalt (Co) > selenium (Se) > mercury (Hg) > and cadmium (Cd) for the polluted site. The geo-accumulation index (I-geo) of the heavy metal Mn in the rainfall around the steel factory site is 6.28 > 5 which indicates extreme contamination. While the Igeo values of Cd, As, and Fe are 4.87, 4.54, and 4.04 > 4 that indicate heavy to extreme contamination, for Pb, 3.80 > 3 indicates moderate to heavy contamination, Cd 1.68 > 1 indicates moderate contamination, Hg 0.46 > 0 indicates uncontaminated to moderate contamination, and Se - 0.36 < 0 indicates uncontaminated. The pollution load index (PLI) of the rainwater around the steel factory site is 13.46 > 1, demonstrating that the area is highly metal-contaminated.

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.

Water-soluble inorganic ions (WSIs) in the aerosols from Central Asia via transboundary transport measured in Jimunai in 2020

Air pollution is a global issue that often transcends national borders, leading to disputes over environmental concerns and climate-mitigation responsibilities. Between March and July 2020, we collected aerosol samples in Jimunai, a town in western China neighboring Kazakhstan, to assess transboundary air pollution in the region. Our analysis focused on major water-soluble inorganic ions (WSIs), with Ca2+ and SO42- accounting for almost 60% of the total ion loading. The ratio of cations to anions was greater than one (1.33 ± 0.27), indicating alkaline aerosols during the sampling period. Our results suggest that the pollutants measured were primarily sourced from Kazakhstan, as demonstrated by local meteorological data, air-mass trajectory analysis, and pollutant emission inventories in Kazakhstan. Correlation and primary component analysis indicated that NH4+ played an important role in neutralizing NO3- and SO42-, while Cl- was significantly depleted by the probable reaction HNO3↑ + NaCl = HCl↑ + NaNO3. These findings highlight the need for continued monitoring and regulation of air pollution sources in the region to address transboundary air pollution.

Seven-year study of monsoonal rainwater chemistry over the mid-Brahmaputra plain, India: assessment of trends and source regions of soluble ions

This work is a 7-year study of monsoonal rainwater chemistry (n = 302), over mid-Brahmaputra plain during 2012 to 2018. The samples were analyzed for major chemical parameters viz. pH, electrical conductivity (EC), and ions (SO₄^2-, NO₃^-, Br^-, Cl^-, F^-, Mg²⁺, Ca²⁺, K⁺, NH₄⁺, Na⁺, and Li⁺) to assess the chemistry. The mean pH of rainwater varied among the years, which was maximum in 2018 (6.18 ± 0.72) and minimum in the year 2014 (5.39 ± 0.54), and the variations were significant at p < 0.0001. Ridgeline plots were drawn to visualize interannual variations, which revealed that Ca²⁺ was the dominant cation in the early years, whereas NH₄⁺ prevailed in the latter years. Mann-Kendall analysis and Sen's slope statistical tests were employed, and it was found that all the ions showed positive S values indicating increasing trends. Enrichment factors (EF) of K⁺, SO₄^2-, and NO₃^- were found to be high with respect to both soil and seawater suggesting the influence of emissions from fossil fuel and biomass burning in the chemistry of rainwater. Principal component analysis (PCA) was applied to identify the sources of rain constituents, and five factors were obtained explaining crustal dust, biomass burning, fossil fuel combustion, agricultural emissions, and coal burning as possible sources. Airmass back trajectory clusters and Potential Source Contribution Function (PSCF) were computed by application of HYbrid Single-Particle Lagrangian Integrated Trajectory model to appreciate the terrestrial influence on the chemistry. The results indicated inputs from both local and regional dust and anthropogenic constituents that influenced the monsoonal rainwater chemistry over Brahmaputra Valley.

The human health risk assessment of particulate air pollution (PM2.5 and PM10) in Romania

Air pollution, especially the concentration of particulate matter (PM_2.5, PM₁₀) is a major issue and is the biggest environmental risk for early death. In the present study, we aimed to estimate the human health risk and to describe the spatial and temporal variation of particulate matter in Romania between 2009 and 2018. The average concentration of PM_2.5 and PM₁₀ particulate matter in the eight studied regions varied between 17.01 and 22.91 µg m⁻³ and 23.02–33.29 µg m⁻³, while the PM_2.5/PM₁₀ ratio varied between 0.52 and 0.76, respectively. The relative risk generated by PM₁₀ in all-cause mortality had a significant variation between the regions, a relative risk of 1.017 in case of Bucharest and1.025 for western regions, with an average of 1.020 ( ± 0.002). According to our observations, a positive relative risk was identified in the case of cardiopulmonary and lung cancer morbidity mainly attributed to PM_2.5 exposure, hence the resulted risk for the country average values was 1.26 ( ± 0.023) and 1.42 ( ± 0.037), respectively. The results revealed that the excess risk and attributable fraction for cardiopulmonary mortality can be reduced by 26.7% and 21.0%. Analyzing the evolution of particulate matters and the possible health impacts of PM_2.5 and PM₁₀ in all region of Romania a strong positive correlation was observed. Since the distributions of PM in different region had significant variation, more investigation is required to understand and decipher the most important regional emission sources for each region. In order to address this issue an in-depth investigation should separately analyze the regional characteristics of air pollution.

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PM_2.5 and PM₁₀ level were 1.82 and 1.35 times higher than annually acceptable limit.

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PMs shows a higher concentration in winter and lower concentration in summer.

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The ratio between the fine and coarse particular matter in Romania was 0.66.

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The relative risk caused by PM_2.5 was higher with one magnitude than the PM_10.

Hurricane/tropical storm rainwater chemistry in the US (from 2008 to 2019)

Rainwater chemistry of extreme rain events is not well characterized. This is despite an increasing trend in intensity and frequency of extreme events and the potential excess loading of elements to ecosystems that can rival annual loading. Thus, an assessment of the loading imposed by hurricane/tropical storm (H/TS) can be valuable for future resiliency strategies. Here the chemical characteristics of H/TS and normal rain (NR) in the US from 2008 to 2019 were determined from available National Atmospheric Deposition Program (NADP) data by correlating NOAA storm tracks with NADP rain collection locations. It found the average pH of H/TS (5.37) was slightly higher (p < 0.05) than that of NR (5.12). On average, H/TS events deposited 14% of rain volume during hurricane season (May to October) at affected collection sites with a maximum contribution reaching 47%. H/TS events contributed a mean of 12% of Ca²⁺, 22% of Mg²⁺, 18% of K⁺, 25% of Na⁺, 7% of NH₄⁺, 6% of NO₃^-, 25% of Cl^- and 11% of SO₄^2- during hurricane season with max loading of 77%, 62%, 94%, 65%, 39%, 34%, 64% and 60%, respectively, which can lead to ecosystems exceeding ion-specific critical loads. Four potential sources (i.e., marine, soil dust, agriculture and industry/fossil fuel) were indicated by PCA. The positive matrix factorization (PMF) suggested Mg²⁺, Na⁺ and Cl^- were primarily marine-originated in both event types, while 36% more sea-salt Ca²⁺ and 33% more sea-salt SO₄^2- were deposited during H/TS. Agriculture and industry/fossil fuel were the main sources of NH₄⁺ and NO₃^-, respectively, in both rain event types. However the NH₄⁺ contribution from industry/fossil fuel increased by 13% during H/TS indicating a potential vehicle source associated with emergency evacuations. This work provides a comprehensive assessment of the rainwater chemistry of H/TS and insight to expected ecosystem loading for future extreme events.

Accumulation of selected metals and concentration of macroelements in liver and kidney tissues of sympatric golden jackal (Canis aureus) and red fox (Vulpes vulpes) in Somogy County, Hungary

This study examined the concentrations of Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn in the liver and kidney samples of golden jackals (n = 163) and red foxes (n = 64). Additionally, we studied how sex affected element concentration in both species, and in the case of golden jackals, how concentration levels were affected by age.Liver was the most important storage organ for Cu, Fe, Mn, and Zn, while kidney for Cd and Na in jackals and foxes.We found no sex-related differences in concentration of any of the selected elements in fox samples. In jackals, the mean concentrations of Al, Mn, and Zn were significantly higher in kidneys of males, while Zn and Cu had higher concentrations in female livers. Our results suggest bioaccumulation processes do not occur in mesocarnivores.Lead and Cd concentrations fell within ranges accepted as normal for canine species and were below toxic levels in the organs of the examined species. Concentrations of Cr, Cu, Fe, Mn, and Zn were far below the toxic levels in both organs of both species, with a slight sign of deficiency of Fe, Mn, and Zn in jackal and fox kidneys. In comparison with toxicity levels and results from other European study sites, the current study demonstrated that species living in the examined area of Somogy County, Hungary, are generally exposed to low levels of environmental contamination.

Lead-adsorbing ionogel-based encapsulation for impact-resistant, stable, and lead-safe perovskite modules

Despite the high-efficiency and low-cost prospect for perovskite solar cells, great concerns of lead toxicity and instability remain for this technology. Here, we report an encapsulation strategy for perovskite modules based on lead-adsorbing ionogel, which prevents lead leakage and withstand long-term stability tests. The ionogel layers integrated on both sides of modules enhance impact resistance. The self-healable ionogel can prevent water permeation into the perovskite layer and adsorb lead that might leak. The encapsulated devices pass the damp heat and thermal cycling accelerated stability tests according to International Electrotechnical Commission 61215 standard. The ionogel encapsulation reduces lead leakage to undetectable level after the hail-damaged module is soaked in water for 24 hours. Even being rolled over by a car followed by water soaking for 45 days, the ionogel encapsulation reduces lead leakage by three orders of magnitude. This work provides a strategy to simultaneously address lead leakage and stability for perovskite modules.

Human health impact assessment and temporal distribution of trace elements in Copșa Mică- Romania

The present study aims to analyze the temporal variations of PM₁₀ and to assess the health risk indexes caused by trace elements from particulate matter (PM₁₀) via inhalation, ingestion, and dermal absorption by adults and children in Copșa Mică (Romania) during 2009–2019. The results revealed a high multi-annual mean concentration of PM₁₀ and trace elements. The analyzed air pollutants showed a decreasing trend during the studied years, therefore 44.11%, 43.48%, 36.07%, 16.02%, and 15.80% lower values were observed for As, Cd, Ni, PM₁₀, and Pb, respectively, due to environmental regulations. The daily exceedance percentage of Pb and Cd was very high, representing 21.74% and 11.26%, followed by PM₁₀ and As concentrations with 4.72% and 3.92%. The ratio between the trace element concentration measured in Copșa Mică and the country average was 2.46, 4.01, 2.44 and 10.52 times higher for As, Cd, Ni and Pb. The calculated Hazard Quotient values via inhalation were higher than the safe limit (1), which accounted 1.81, 3.89 and 4.52, for As, Cd and Ni, respectively, indicating that the trace elements might present a non-carcinogenic risk to both adults and children. Furthermore, the concentration of all studied trace elements in Copșa Mică showed cancer risk for adults via inhalation and dermal absorption as well.

Spatial distribution of trace elements (As, Cd, Ni, Pb) from PM10 aerosols and human health impact assessment in an Eastern European country, Romania

In the present study, the concentrations of trace elements in PM₁₀ were determined and analyzed at 115 monitoring stations in Romania throughout the period 2009-2018. The spatiotemporal distribution of trace element concentrations of PM₁₀, the source apportionment and health impact assessment, was carried out. The results showed a very high multi-annual mean concentration for PM₁₀ and trace elements as well. The multiannual average concentration of PM₁₀ was higher by 29.75% than the World Health Organization recommendation. All studied air pollutants showed a decreasing trend during the studied years, showing with 17.84%, 50.21%, 43.36%, 11.27%, and 72.09% lower values for PM₁₀, As-, Cd-, Ni-, and Pb-, respectively, due to environmental regulations. To assess the human health impact, the hazard quotient (HQ) and cancer risk (CR) were calculated using the health risk model developed by the US Environmental Protection Agency (EPA). The Cd and Ni might present a non-carcinogenic risk to both adults and children; however, the hazard quotient values are higher than the safe limit, with 9.53 and 1.93, respectively. In addition, our study results revealed that the inhalation of As, Cd and the dermal absorption of all studied trace elements were considered as the most important risk factors for developing cancer, especially in case of adults.

Rainwater Chemistry Reveals Air Pollution in a Karst Forest: Temporal Variations, Source Apportionment, and Implications for the Forest

Temporal rainwater chemistry was used to reveal air pollution in the Maolan National Karst Forest Park (MNKFP), which is representative of the typical karst forest region of southwest China (SW China). The rainwater ions’ sources, variations, trends, and potential environmental effects were investigated from 2007 to 2010 and from 2013 to 2014. Based on the analysis of the temporal ionic concentrations of rainwater in the MNKFP, significant variations of ions were observed, including in NH4+ (9.7~266.6 μeq L−1) and SO42− (14.5~1396.4 μeq L−1), which were mainly controlled by variations in the source and rainfall amount; a decreased trend of rainwater pH was also observed. Accordingly, NH4+, Ca2+, SO42−, and Cl− were regarded as the most dominant ions. Typical ionic ratios and positive matrix factorization (PMF) model-based source apportionment suggested that anthropogenic inputs (coal combustion, industrial, traffic, and agricultural emissions) contributed 51% of F−, 93% of NO3−, 62% of SO42−, and 87% of NH4+, while the natural sources (crustal dust and sea salt) were the main sources of Cl− (74%), Na+ (82%), K+ (79%), Mg2+ (94%), and Ca2+ (93%). In combination with the reducing neutralization trend of temporal rainwater observed in the MNKFP and the potential effect of rainwater ion deposition on karst forests, more detailed monitoring of the rainfall-related deposition process is required for a better understanding of its potential environmental effects on the Earth’s surface.

Chemistry and Microbiology of Urban Roof Runoff in Kraków, Poland with Ecological and Health Risk Implications

Urban rainwater samples, collected in various districts of Kraków during the period from the spring of 2019 to the winter of 2020, were investigated, and relevant risk implications were assessed. The contents of 31 components were determined, including: bacteria, fungi, pH, EC, Cl-, N-NO3, P-PO4, SO42-, SiO2, K, Mg, Ag, Al, Ba, Ca, Cu, K, Mg, Mo, Na, Pb, Sb, and Zn. The highest contents of the investigated elements were determined in the industrial (eastern) part of Kraków. The values of toxicity potential were <1, indicating a lack of ecological risk. The value of contamination degree indicated moderate rainwater contamination in all analyzed elements (Cdeg = 9.44). The total non-carcinogenic risk values, in both adults (hazard quotient (HQ) = 1.38) and children (HQ = 2.54), exceeded the acceptable level of one. Regarding individual elements in dermal contact, the acceptable level of 1 × 10−6 was exceeded in Pb (adults carcinogenic risk (CR) = 4.87 × 10−5, children CR = 2.23 × 10−5). The contents of the analyzed chemical compounds did not exceed the permissible levels adopted for drinking water; however, rainwater was significantly contaminated with respect to its microbiological parameters. Rainwater was suitable for non-potable use.

Determining rainwater chemistry to reveal alkaline rain trend in Southwest China: Evidence from a frequent-rainy karst area with extensive agricultural production

Rainwater chemistry plays an important role in the earth-surficial ecosystem, but studies on rainwater chemical composition of karst agro-ecosystem are rare. To explore the rainwater alkalization and the provenance of components responsible for neutralization, two-years chemical monitoring of rainwater was carried out in a karst agricultural catchment in Southwest China. The main findings suggest that SO₄^2-, NO₃^-, Ca²⁺, and NH₄⁺ are the principal ions. All the ionic contents show distinctly seasonal variation (highest in winter) in response to variations in seasonal precipitation because the rain-scour process can efficiently remove atmospheric materials. Source identification indicates that Cl^- and Na⁺ are mainly derived from marine input whereas SO₄^2- and NO₃^- are controlled by anthropogenic emission, in particular, fixed emission sources. The source of NH₄⁺ is attributed to intense agricultural production, while Ca²⁺ and Mg²⁺ are mainly derived from calcite dissolution. The rainwater alkalization caused by the seasonal acid neutralization (via basic components, Ca²⁺ and NH₄⁺) is beneficial to crop growth but also reflect agricultural overfertilization. Sulfur controlled the total wet acid deposition (68%-94%) and could be a potential agent of weathering.

Major air pollutants seasonal variation analysis and long-range transport of PM10 in an urban environment with specific climate condition in Transylvania (Romania)

The air quality decrease, especially in urban areas, is related to local-scale conditions and to dispersion of air pollutants (regional and long-range) as well. The main objective of this study was to decipher the seasonal variation of PM10, NO, NO2, NOx, SO2, O3, and CO over a 1-year period (2017) and the possible relationships between air pollution and meteorological variables. Furthermore, trajectory cluster analysis and concentration-weighted trajectory (CWT) methods were used to assess the trajectories and the source-receptor relationship of PM10 in the Ciuc basin Transylvania, known as the "Cold Pole" of Romania. The pollutants show lower concentrations during warmer periods, especially during summer, and significantly higher concentrations were observed on heating season in winter due to seasonal variations in energy use (biomass burning) and atmospheric stability. Subsequently, in February, the highest concentration of PM10 was 132 μg/m3, which is 4 times higher than the highest recorded monthly mean. Our results indicate a negative correlation between CO/temperature (- 0.89), NOx/temperature (- 0.84) and positive between NOx/PM10 (0.95), CO/PM10 (0.9), and NOx/CO (0.98), respectively. Dominant transport pathways were identified and the results revealed that slow-moving southerly (~ 45%) and northwesterly (~ 32%) air masses represent almost 80% and mainly regional flows were discerned. During 2017, increased PM10 levels were measured at the study site when air masses arrived mostly from northwest and southeast. The CWT and polarplot models show a strong seasonal variation and significant differences were observed between weekdays and weekends, namely highest PM10 concentrations during weekends at low wind speed (2-4 m/s).