The occurrence and profiles of 14 triester organophosphate flame retardants (OPFRs) and plasticizers were investigated in surface water, tap water, rainwater, and seawater collected from New York ...State. In total, 150 samples collected from rivers (n = 35), lakes (n = 39), tap water (n = 58), precipitation/rainwater (n = 15), and seawater (n = 3) were analyzed for 14 organophosphate esters (OPEs). An additional nine Hudson River water samples were collected periodically to delineate seasonal trends in OPE levels. The total concentrations of OPEs were found at part-per-trillion ranges, with average concentrations that ranged from 0.01 ng/L for tripropyl phosphate (TPP) in river water to 689 ng/L for tris(2-butoxyethyl)phosphate (TBOEP) in lake water. Tris(1-chloro-2-propyl)phosphate (TCIPP) was the most abundant compound among the investigated OPEs in all types of water. The concentrations of OPEs in river-, lake-, and rainwater were similar but >3 times higher than those found in tap water. Chlorinated alkyl OPFRs accounted for a major proportion of total concentrations. TCIPP, TBOEP, and triethyl phosphate (TEP) were found in >90% of the samples analyzed. Wet deposition fluxes for 14 OPFRs were estimated, on the basis of the concentrations measured in rainwater in Albany, New York, and the values were between 440 and 5250 ng/m2. Among several surface water bodies analyzed, samples from the Hudson River and Onondaga Lake contained elevated concentrations of OPEs. Estimated daily intake of OPEs via the ingestion of drinking water was up to 9.65 ng/kg body weight/day.
Abstract On 3 February 2023, a Norfolk Southern train derailment occurred in East Palestine, Ohio. The accident and subsequent fire resulted in the emissions of large amounts of hazardous compounds ...to the ambient atmosphere over many days. We used precipitation chemistry measurements routinely collected by the National Atmospheric Deposition Program (NADP) to estimate the spatial extent and chemical compounds deposited as a result of the accident. Our measurements revealed a large areal impact from the Midwest through the Northeast and likely Canada, and perhaps as far south as North Carolina (portions of 16 states, 1.4 million km 2 ). Observations showed the expected high chloride concentrations, but also unexpectedly high pH (basic) and exceptionally elevated levels of base cations exceeding 99th percentiles versus the historic record. These results were consistent with the meteorological conditions and atmospheric trajectories, and were not due to highly-concentrated low volume precipitation samples or wildfires. The robust measurements of the NADP network clearly show that the impacts of the fire were larger in scale and scope than the initial predictions, and likely due to the uplift from the fire itself entraining pollutants into the atmosphere. A more detailed evaluation of the accident and resulting fire could further refine the full impact of the atmospheric concentrations, dry and wet deposition, and the more specific extent of the spatial impact.
Decabromodiphenyl ether (BDE209) has been subject to restrictions since 2018 in developed countries but is still manufacturing in China. Decabromodiphenyl ethane (DBDPE) is widely used as a ...replacement for BDE209. To better understand the behaviors and fates of these legacy and novel brominated flame retardants (BFRs), water samples were collected from the estuaries of 36 rivers that drain into the Bohai Sea (BS) and North Yellow Sea (NYS) in 2017 and 2018. The results showed that BDE209 was still the predominant compound with a median concentration of 2470 pg L−1, whereas DBDPE had a median concentration of 129 pg L−1. Spatially, relatively high concentrations were observed in the rivers near Laizhou Bay (LB), which is the manufacturing hub of BFRs. BDE209 concentrations were significantly higher in dry season than in wet season, which indicates a dominant process of dilution by precipitation during the wet season. DBDPE concentration showed no significant seasonal difference. This implies that wet deposition was the major additional source of DBDPE during the wet season, and the concentration increased further during the autumn as a result of a time-lag effect. The BFR concentrations in urban rivers were lower than those reported by a study undertaken in August 2013. An increase in the BFR concentrations in rural rivers since 2013 suggested increases in the use and non-point source emissions of BFRs in some remote aquatic environments. The estimated annual inputs of BDE209 and DBDPE into the BS were ∼95.9 kg yr−1 and ∼26.8 kg yr−1, respectively, whereas those into the NYS were ∼24.1 kg yr−1 and ∼8.38 kg yr−1. The results revealed an ecological risk of BDE209 in winter especially in the Xiaoqing River, thus suggesting the impact of BDE209 on the aquatic environment and human health.
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•BDE 209 was the predominant compounds in rivers around the Bohai Sea.•Extremely higher levels of BDE 209 were found in dry season than in wet season.•Wet deposition is an important additional source of DBDPE in rivers.•BFRs increased in rural rivers but decreased in urban rivers within recent five years.•BDE209 may has reached a quasi-steady state but DBDPE showed an unsteady discharge.
Capsule: Contrast to DBDPE, BDE209 is the predominant BFRs in rivers and shows distinct seasonal variation due to the dilution effect of rainwater in wet season.
•Quantified 10 PFAS in rainwater at 7 sites in the U.S.•HFPO-DA (GenX) was detected in rainwater at all sites•PFOA concentrations in rainwater ranged from 0.2-30 ng L-1•Correlation plots allow rapid ...visual comparison of multi-analyte, multi-site data•Statistical models show influence of local point sources on PFAS profiles in rain
Per- and polyfluoroalkyl substances (PFAS) are transported in the atmosphere, leading to both wet and dry deposition to the surface. The concentrations of 15 PFAS were measured at six locations in the Ohio-Indiana region of the U.S. during the summer of 2019 and compared to samples collected at a distant site in NW Wyoming. ΣPFAS concentrations ranged from 50-850 ng L−1, with trifluoroacetic acid (TFA) being the dominant compound (~90%). Concentrations of perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) were similar to amounts observed over the past 20 years, indicating persistence in the atmosphere despite regulatory action, and the newer species HFPO-DA (GenX) was also widely detected in rainwater. ANOVA modeling and correlation matrices were used to determine association of PFAS concentrations, location, and functional group and chain length. Statistically significant differences (p < 0.05) in PFAS profiles across sites separated by 10-100 km indicate that local point sources strongly contribute to wet deposition. This work introduces correlation plots for PFAS that allow rapid visual comparison of multi-analyte and multi-site data sets.
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The Congo River supplies vast quantities of trace metals (TMs) to the South Atlantic Ocean, but TM budgets for the Congo plume derived using radium isotopes for GEOTRACES cruise GA08 suggest ...additional input other than the river outflow. Considering the tight correlations between most dissolved TMs and salinity in the plume and the high rainfall during the wet season over the Congo shelf, we hypothesized that wet atmospheric deposition is a TM source to the Congo plume. Observed TM concentrations in rainwaters across the Congo shelf were mostly comparable to values from previous work in the North Atlantic and Mediterranean Sea. Wet deposition contributed the equivalent of 43% dCd, 21% dCu, 20% dPb and 68% dZn of the Congo River fluxes. Our findings show an important role of wet deposition in supplying TMs to the South Atlantic overlapping with the region that receives substantial TM fluxes from the Congo River.
Plain Language Summary
The Congo River has the second largest freshwater discharge volume globally and creates an extensive near‐equatorial plume into the Atlantic Ocean. The Congo plume constitutes an important source of trace metals (TMs) to the ocean, which impacts biogeochemical cycles in the tropical and subtropical ocean. However, existing work suggests a discrepancy within the TM budgets in the Congo plume and points to unknown source other than the Congo River or shelf sediments. Most TM concentrations across the Congo plume remain tightly correlated with salinity, suggesting that any additional sources are likely also freshwater‐derived or enter the ocean at the river mouth coincidently with direct riverine TM inputs. Here, TM concentrations in ocean, river and rainwater collected during the GEOTRACES GA08 cruise are combined to suggest that wet deposition augmented some Congo TM fluxes to the ocean. Fluxes of anthropogenic Cd, Cu, Pb and Zn to the Congo shelf from wet deposition are of the same order of magnitude as the Congo River. Concentrations of these elements in rainwater are similar to prior observations reported for the North Atlantic and Mediterranean Sea, suggesting that a large fraction of the global range of rainwater concentrations over the ocean has been captured in our observations.
Key Points
The Congo River is an important source of trace metals (TMs) to the South Atlantic Ocean revealed by data from GEOTRACES cruise GA08
Wet deposition (rainfall) is identified as an additional TM source to the Congo plume by concurrently considering river and rain data
Rainfall supplies anthropogenic dTMs (Cd, Cu, Pb and Zn) with fluxes equivalent to 20%–68% of those from the Congo River on the Congo shelf
A comprehensive analysis of the chemical composition of precipitation was performed on rainwater samples collected between 1978 and 2017 over the conterminous US. A total of 86470 data records ...downloaded from the National Atmospheric Deposition Program were statistically analyzed and assessed in terms of precipitation chemistry. The ion abundance followed the Cl⁻ > Na⁺ > SO₄2⁻ > Ca2⁺ > H⁺ > NH₄⁺ > NO₃⁻ > Mg2⁺ > HCO₃⁻ > K⁺ downward trend, showing that chloride and sodium were the most dominant among anions and cations. Ca2+, SO42− and NH4+ concentrations were notable in desert areas or in regions with significant anthropogenic activity. Frequency analysis of pH values showed that the 87.90% of the pH is acidic, exhibiting values under 5.6. According to the acidifying and neutralization potential, rainwater pH is mostly alkaline in the Western region, presenting acidic values in highly industrialized areas, in the Central and Eastern Regions. Fractional acidity showed that in the majority of the studied sampling sites 61% of the acidity in precipitation is neutralized, due to the presence of the main neutralizing agents (NH4+, Ca2+, Na+), fact sustained by the neutralization factor values. The relationship between acidic and alkaline components was thoroughly examined by ionic ratios and the ammonium availability index. Wet deposition rates of major ions confirmed the dominance of acidic species over neutralizing ones, as well as the significant imprint of regional climate and heavily industrialized areas on the precipitation chemistry. The complex major ion source apportionment, including marine and crustal enrichment factors, sea salt and non-sea salt fractions, Spearman's rank correlation analysis and Principal Component Analysis, showed that anthropogenic influences are the most significant, including coal-fired power plants, oil refineries, major industries and agricultural activities. Crustal and marine sources also presented a prominent imprint on the rainwater chemistry of the conterminous US.
•Spatial and long-term analysis on the rainwater chemistry during 1978–2017.•Frequency analysis showed that the 87.90% of the precipitation pH is acidic.•The effects of regional climate and heavily industrialized areas were highlighted.•The contributions of anthropogenic, crustal and marine sources were revealed.
The March 2011 Fukushima Dai-ichi Nuclear Power Plant accident in Japan released 520 PBq of radionuclides compared to a total release of 5300 PBq from the Chornobyl Nuclear Power Plant accident. Both ...nuclear accidents resulted in deposition of radiocesium throughout the northern hemisphere, and a plethora of studies have been performed regarding radiocesium (137Cs) behavior. However, few studies have assessed the impact of precipitation on 137Cs deposition in forests. Wide-scale environmental measurements from 2011 and 2016 were used to determine the differences in 137Cs deposition because of precipitation following the Fukushima accident. In areas where wet deposition processes were dominant, dense forests generally had lower ambient dose rates and levels of contamination on forest floors than other stands with fewer stems per hectare in 2011. Similar tendencies were not observed in areas that were primarily subject to dry deposition nor were any trends observed in 2016. 137Cs was retained in dense forest canopies for an extended period regardless of the deposition mode. Additionally, it was found that the initial retention of radionuclides by forest canopies is in general higher for areas with predominantly dry deposition. Incorporation of radiocesium into wood tissues was the same for both wet and dry deposition.
South Asian pollutants can be transported and deposited via wet/dry deposition to the remote areas of the Himalayas and could pose a serious threat to the mountain ecosystems. Therefore, in order to ...understand the concentrations, fluxes, seasonal variation and origin of the mercury (Hg), major ions and trace elements, precipitation samples were collected during 2012–2013 from a data gap region, Jomsom, the high elevation semi-arid mountain valley in the central Himalayas. The volume-weighted mean (VWM) concentrations of ions followed the order of Ca2+ > Mg2+ > Na+ > NH4+ > SO42− > Cl− > NO3− > K+. The concentration of Cd was lowest (0.07 μg L−1) whereas that of Fe was the highest (1073.59 μg L−1) in the precipitation samples. Wet deposition level of all the measured inorganic species was comparable to urban Lhasa but higher than those in remote alpine sites of the Tibetan Plateau (TP). This study shows that Hg and other inorganic constituents were higher in the non-monsoon season compared to monsoon due to enhanced washout of aerosols. Enrichment factor (EF), sea salt fraction, crustal and anthropogenic fractions, principal component analysis (PCA) and correlation coefficient analysis suggested that crustal dust and anthropogenic activities as the major sources of measured chemical species whereas the influence of sea-salt was minimal. In addition, local anthropogenic emissions were low suggesting that the majority of the pollutants could have been transported from the South Asian region to the high elevation mountains. Meanwhile, low precipitation and dry environment could have enhanced the concentrations of inorganic species in the arid region than other sites over the central Himalayas. This work adds new dataset of inorganic pollutants in wet precipitation and provides baseline information for an arid region environmental protection. However, there is a need for further long-term monitoring to understand the precipitation chemistry of the arid regions.
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•Over 1-year dataset of wet precipitation chemistry in semi-arid mountain site of the central Himalayas is presented•Concentrations of Hg, major ions and trace elements were higher during the non-monsoon season•Sources for chemical constituents in precipitation were dominated by crustal and anthropogenic•Long-range transport of pollutants via trans-Himalayan valley can significantly impact to the higher Himalayas
Current research suggests that, apart from photochemical reactions, toluene, ethylbenzene and xylene (TEX) removal from ambient air might be affected by atmospheric precipitation, depending on the ...concentrations and water solubility of the compounds, Henry's law, physico-chemical properties of the water, as well as the frequency and intensity of precipitation events. Nevertheless, existing knowledge of the role that wet deposition plays in biogeochemical cycles of volatile species remains insufficient, and this topic requires more scientific effort to be explored and understood. In this study, we employed the eXtreme Gradient Boosting tree ensemble for revealing TEX transfer from ambient air to rainwater, and applied a novel SHapley Additive exPlanations feature attribution framework to examine the relevance of the monitored parameters and identify key factors that govern wet deposition of TEX. According to the results, main impacts, including ambient air TEX concentrations, and rainwater and air temperatures, and occasional, but less important impacts, including wind speed, air pressure, turbidity, and total organic carbon, NO3−, Cl− and K+ rainwater concentration, shaped TEX partition between gaseous and aqueous phases during rain events.
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•XGBoost and SHAP methods were applied to investigate TEX air – rainwater partition.•XGBoost relative errors were below 20% when evaluating variable relationships.•Air TEX concentrations, rainwater and air temperature govern TEX distribution.•Ion rainwater concentrations and wind speed occasionally impact TEX transfer.
Anthropogenic activities have led to large-scale mercury (Hg) pollution in the Arctic. It has been suggested that sea-salt-induced chemical cycling of Hg (through 'atmospheric mercury depletion ...events', or AMDEs) and wet deposition via precipitation are sources of Hg to the Arctic in its oxidized form (Hg(ii)). However, there is little evidence for the occurrence of AMDEs outside of coastal regions, and their importance to net Hg deposition has been questioned. Furthermore, wet-deposition measurements in the Arctic showed some of the lowest levels of Hg deposition via precipitation worldwide, raising questions as to the sources of high Arctic Hg loading. Here we present a comprehensive Hg-deposition mass-balance study, and show that most of the Hg (about 70%) in the interior Arctic tundra is derived from gaseous elemental Hg (Hg(0)) deposition, with only minor contributions from the deposition of Hg(ii) via precipitation or AMDEs. We find that deposition of Hg(0)-the form ubiquitously present in the global atmosphere-occurs throughout the year, and that it is enhanced in summer through the uptake of Hg(0) by vegetation. Tundra uptake of gaseous Hg(0) leads to high soil Hg concentrations, with Hg masses greatly exceeding the levels found in temperate soils. Our concurrent Hg stable isotope measurements in the atmosphere, snowpack, vegetation and soils support our finding that Hg(0) dominates as a source to the tundra. Hg concentration and stable isotope data from an inland-to-coastal transect show high soil Hg concentrations consistently derived from Hg(0), suggesting that the Arctic tundra might be a globally important Hg sink. We suggest that the high tundra soil Hg concentrations might also explain why Arctic rivers annually transport large amounts of Hg to the Arctic Ocean.
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