Atmospheric Deposition Rates Research Articles

Has nitrogen availability decreased over much of the land surface in the past century? A model-based analysis

A recent publication (Mason et al. in Science 376:261, 2022a) suggested that nitrogen (N) availability has declined as a consequence of multiple ongoing components of anthropogenic global change. This suggestion is controversial, because human alteration of the global N cycle is substantial and has driven much-increased fixation of N globally. We used a simple model that has been validated across a climate gradient in Hawai ‘i to test the possibility of a widespread decline in N availability, the evidence supporting it, and the possible mechanisms underlying it. This analysis showed that a decrease in δ15N is not sufficient evidence for a decline in N availability, because δ15N in ecosystems reflects both the isotope ratios in inputs of N to the ecosystem AND fractionation of N isotopes as N cycles, with enrichment of the residual N in the ecosystem caused by greater losses of N by the fractionating pathways that are more important in N-rich sites. However, there is other evidence for declining N availability that is independent of 15N and that suggests a widespread decline in N availability. We evaluated whether and how components of anthropogenic global change could cause declining N availability. Earlier work had demonstrated that both increases in the variability of precipitation due to climate change and ecosystem-level disturbance could drive uncontrollable losses of N that reduce N availability and could cause persistent N limitation at equilibrium. Here we modelled climate-change-driven increases in temperature and increasing atmospheric concentrations of CO2. We show that increasing atmospheric CO2 concentrations can drive non-equilibrium decreases in N availability and cause the development of N limitation, while the effects of increased temperature appear to be relatively small and short-lived. These environmental changes may cause reductions in N availability over the vast areas of Earth that are not affected by high rates of atmospheric deposition and/or N enrichment associated with urban and agricultural land use.

Nitrogen compounds at Mexican and USA coasts on the Gulf of Mexico

In recent decades, anthropogenic emissions in the Gulf of Mexico have caused a deterioration in air quality in surrounding areas, mainly due to particulate matter, sulfur dioxide and nitrogen dioxide. Over this period, interest in reactive nitrogen compounds has increased due to their relationships to air quality and ecosystem impacts associated with atmospheric deposition. In this study we summarize air concentrations of nitrogen dioxide in ambient air and wet atmospheric deposition of nitrate and ammonium along the southern coast of the United States of America and eastern Mexico over the period 2017 to 2020. The highest concentrations of ammonium and nitrate were observed in precipitation at Texas and sites in Mexico, although the highest rates of atmospheric deposition were observed in Florida and Louisiana. The ratio between ammonium and nitrate in precipitation was higher at Mexican stations than in studied sites in the United States, influenced by meteorological factors, atmospheric emissions, and characteristic air mass transport in the region. Back trajectory modeling showed the importance of the seasonality of the wind in the transport of nitrogen compounds of local and regional origin that affect Veracruz.

A Multicompartment Assessment of Microplastic Contamination in Semi-remote Boreal Lakes.

Microplastic contamination is ubiquitous across the globe, even in remote locations. Still, the sources and pathways of microplastics to such locations are largely unknown. To investigate microplastic contamination in a semi-remote location, we measured microplastic concentrations in nine oligotrophic lakes within and around the International Institute for Sustainable Development-Experimental Lakes Area in northwestern Ontario, Canada. Our first objective was to establish ambient concentrations of microplastics in bottom sediments, surface water, and atmospheric deposition in semi-remote boreal lakes. Across all lakes, mean shallow and deep sediment microplastic concentrations, near-surface water microplastic concentrations from in situ filtering, and dry atmospheric microplastic deposition rates were 551 ± 354 particles kg-1, 177 ± 103 particles kg-1, 0.2 ± 0.3 particles L-1, and 0.4 ± 0.2 particles m-2 day-1, respectively. Our second objective was to investigate whether microplastic contamination of these lakes is driven by point sources including local runoff and direct anthropogenic inputs or nonpoint sources such as atmospheric deposition. Lakes were selected based on three levels of anthropogenic activity-low, medium, and high-though activity levels were minimal across all study lakes compared with highly populated areas. Whereas a positive correlation would indicate that point sources were a likely pathway, we observed no relationship between the level of anthropogenic activity and microplastic contamination of surface water. Moreover, the composition of microplastics in surface water and atmospheric deposition were similar, comprising mostly polyester and acrylic fibers. Together, these results suggest that atmospheric deposition may be the main pathway of microplastics to these remote boreal lakes. Environ Toxicol Chem 2024;43:999-1011. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Similarities in Storage and Transport of Sulfate in Forested and Suburban Watersheds, Despite Anthropogenically Elevated Suburban Sulfate

AbstractSulfate is a potential pollutant and important nutrient linked with the nitrogen, carbon, and phosphorus cycles. The importance of different anthropogenic sulfate sources in suburban streams (septic systems, fertilizer, road salt, and infrastructure) is uncertain, and the temporal dynamics of stream export sparsely documented. We study sources and export dynamics of sulfate in suburban and forested headwater catchments. Stream baseflow discharge and sulfate concentrations were strongly positively correlated in both watersheds with the highest values in spring. Suburban concentrations and fluxes (2.48–7.5 mg/L or 25.8–78.1 μM, 16.6 kg/ha/yr) were consistently higher than forested (0.56–2.78 mg/L or 5.8–28.9 μM, 5 kg/ha/yr). Following precipitation, sulfate concentrations in both forested and suburban streams increased to concentrations above pre‐storm values and remained high after peak discharge. These dynamics suggest that both catchments have a large pool of sulfate that can be mobilized under wet conditions. Ridge‐top forest soil samples contained 210 kg/ha stored, extractable sulfate. Current atmospheric sulfate deposition rates (5–7 kg/ha/yr) are approximately in balance with sulfate export in the forested stream. In the suburban watershed, we estimated septic fields contribute up to 11 kg/ha/yr (about half from surfactants) and lawn care up to 4.3 kg/ha/yr and are the most likely sources of elevated stream sulfate. Sulfate sulfur (4.9–5.8‰ forested; 6.1–7.0‰ suburban) and oxygen isotope values (0.7–2.0‰ forested; −0.1–4.1‰ suburban) are consistent with this interpretation, but do not provide strong corroboration due to large variation and overlap in estimated source values.

Combining multiple investigative approaches to unravel functional responses to global change in the understorey of temperate forests

AbstractPlant communities are being exposed to changing environmental conditions all around the globe, leading to alterations in plant diversity, community composition, and ecosystem functioning. For herbaceous understorey communities in temperate forests, responses to global change are postulated to be complex, due to the presence of a tree layer that modulates understorey responses to external pressures such as climate change and changes in atmospheric nitrogen deposition rates. Multiple investigative approaches have been put forward as tools to detect, quantify and predict understorey responses to these global‐change drivers, including, among others, distributed resurvey studies and manipulative experiments. These investigative approaches are generally designed and reported upon in isolation, while integration across investigative approaches is rarely considered. In this study, we integrate three investigative approaches (two complementary resurvey approaches and one experimental approach) to investigate how climate warming and changes in nitrogen deposition affect the functional composition of the understorey and how functional responses in the understorey are modulated by canopy disturbance, that is, changes in overstorey canopy openness over time. Our resurvey data reveal that most changes in understorey functional characteristics represent responses to changes in canopy openness with shifts in macroclimate temperature and aerial nitrogen deposition playing secondary roles. Contrary to expectations, we found little evidence that these drivers interact. In addition, experimental findings deviated from the observational findings, suggesting that the forces driving understorey change at the regional scale differ from those driving change at the forest floor (i.e., the experimental treatments). Our study demonstrates that different approaches need to be integrated to acquire a full picture of how understorey communities respond to global change.

Riverine nitrogen source and yield in urban systems

Although human reshaping of the nitrogen (N) cycle is well established, contributions of individual N sources to riverine and coastal eutrophication are less certain. Urban N fluxes are potentially substantial, particularly from sewer overflows. Results from four longitudinal surveys in rivers in and around the city of Pittsburgh, Pennsylvania, were used to characterize N chemistry and isotopic composition and were compared with LOADEST‐model‐derived total N (TN) flux budgets from three urban areas along the Ohio River (Pittsburgh, Pennsylvania; Cincinnati, Ohio; and Louisville, Kentucky). Triple nitrate isotopes reveal that riverine nitrate in the Pittsburgh region is dominated by wastewater inputs despite high atmospheric deposition rates. Our budget estimates demonstrate that the magnitude of urban N yields is comparable to yields reported for agricultural watersheds and that these high urban N yields cannot consist of permitted, point‐source discharges alone. Our results reveal that nonpoint sources in urban systems represent an important but overlooked source of TN to overall riverine budgets.

Influence of atmospheric dust deposition on sinking particle flux in the northwest Pacific

We examined the flux and composition of sinking particles collected at a water depth of 800 m in the northwest Pacific from November 2017 to August 2018 to assess the impact of dust deposition on organic carbon export. The fluxes of total particulate matter and particulate organic carbon averaged over the study period were 88 ± 63 mg m-2 d-1 and 9.0 ± 5.8 mg m−2 d−1, respectively. Biogenic particles accounted for 82% of the sinking particles, on average. There were two notable pulses in the particle fluxes of both biogenic and lithogenic material in February and May 2018. These flux peaks were decoupled from net primary production in the surface waters but coincided with intervals of high rates of atmospheric dust deposition. The biogenic component of the two peaks was dominated by two different phytoplankton communities, which may have influenced carbon export efficiency. Correlations between the sinking particle flux and the lithogenic flux are found at several locations in the northwest Pacific, implying that East Asian dust deposition has a prevalent influence on the biological pump. Attention should be paid to the effects of changes in the continental dust supply to the oceans on oceanic carbon export.

A nationwide monitoring of atmospheric microplastic deposition

Plastic production continues to increase every year, yet it is widely acknowledged that a significant portion of this material ends up in ecosystems as microplastics (MPs). Among all the environmental compartments affected by MPs, the atmosphere remains the least well-known. Here, we conducted a one-year simultaneous monitoring of atmospheric MPs deposition in ten urban areas, each with different population sizes, economic activities, and climates. The objective was to assess the role of the atmosphere in the fate of MPs by conducting a nationwide quantification of atmospheric MP deposition. To achieve this, we deployed collectors in ten different urban areas across continental Spain and the Canary Islands. We implemented a systematic sampling methodology with rigorous quality control/quality assurance, along with particle-oriented identification and quantification of anthropogenic particle deposition, which included MPs and industrially processed natural fibres. Among the sampled MPs, polyester fibres were the most abundant, followed by acrylic polymers, polypropylene, and alkyd resins. Their equivalent sizes ranged from 22 μm to 398 μm, with a median value of 71 μm. The particle size distribution of MPs showed fewer large particles than expected from a three-dimensional fractal fragmentation pattern, which was attributed to the higher mobility of small particles, especially fibres. The atmospheric deposition rate of MPs ranged from 5.6 to 78.6 MPs m−2 day−1, with the higher values observed in densely populated areas such as Barcelona and Madrid. Additionally, we detected natural polymers, mostly cellulosic fibres with evidence of industrial processing, with a deposition rate ranging from 6.4 to 58.6 particles m−2 day−1. There was a positive correlation was found between the population of the study area and the median of atmospheric MP deposition, supporting the hypothesis that urban areas act as sources of atmospheric MPs. Our study presents a systematic methodology for monitoring atmospheric MP deposition.

Coal-derived rates of atmospheric dust deposition during the Jurassic-Cretaceous greenhouse periods

The study of dust deposition records in geological history is of great significance to the study of paleoclimate evolution during deep periods. Because dust can directly influence the biochemical processes and climate evolution of the Earth. However, the absence of quantitative data on dust limits the systematic and comprehensive study of paleoclimate evolution during deep periods. Prior to the Quaternary period, most quantitative studies on atmospheric dust have focused on the Permian era. However, in the entire Mesozoic era, there are still no quantitative data available on atmospheric dust deposition rates. We utilized the average concentration of inorganic matter in coal from the Jurassic and Cretaceous periods to depict the dust concentration and corresponding dust deposition rate in the atmospheric system during these periods. We also conducted a correlation analysis using the distribution of arid source areas. The results show that the values of ash concentration and dust deposition rates are higher near the arid provenance and lower far away from it. Furthermore, in this study, we have compared the latitudinal variation gradient of dust deposition rates under the icehouse and greenhouse climates by using the end of the Permian and Quaternary as representatives of icehouse climate and the Jurassic and Cretaceous periods as representatives of the greenhouse climate. Our findings indicate that there is a higher ash concentration, dust deposition rate, and dust deposition rate variation gradient in the air under the icehouse climate, while there is a lower ash concentration, dust deposition rate, and dust deposition rate gradient in the air under the greenhouse climate. We have also discussed the dust sources during the Mesozoic period, as well as the differences in ash data under greenhouse and icehouse conditions. This provides a strong basis for studying the atmospheric environment after the modern climate entered the ice age.

Spatial distribution of atmospheric microplastics in bulk-deposition of urban and rural environments – A one-year follow-up study in northern Germany

Atmospheric microplastic deposition rates play a crucial role for calculating the input of microplastics in the environment and to further understand pollution patterns. In this study, the spatial and temporal distribution of atmospheric microplastic particles in urban and rural areas of Northern Germany was investigated. Therefore, eleven structurally diverse locations in Hamburg and Mecklenburg-Western Pomerania were equipped with bulk-deposition samplers in triplicates and sampled monthly between August 2019 and July 2020. The resulting 306 samples were treated with hydrogen peroxide (30 %) and sodium hypochlorite (6–14 %) to digest biological organic matter. The filters were subsequently stained with the lipophilic dye Nile Red and underwent visual microplastic identification via fluorescence microscopy. Fragments and fibers were quantified down to a cut-off size of 10 μm. The polymer composition of microplastic particles was investigated along a subset of particles via μ-Raman spectroscopy.The microplastic deposition rate for Northern Germany (89 ± 61 MP/m2/day) is in the same order of magnitude as those reported by previous studies. Significant differences in microplastic deposition rates were found between urban and rural sampling sites. Population density was identified as an important factor for greater amounts of microplastics and higher shares of fibers in urban samples. Special attention was given to the canopy cover at two forested sampling sites and an influence of the comb-out effect on atmospheric microplastic deposition was detected.

Interacting effects of urbanization and climate on atmospheric deposition of phosphorus around the globe: A meta-analysis

Over half of the world's human population currently lives in cities, and population density in urban areas is projected to increase over the coming decades. Past studies have shown cities to be hotspots for atmospheric deposition of nitrogen and researchers have found individual cities to have elevated rates of atmospheric phosphorus deposition. However, it remains unknown whether atmospheric phosphorus inputs are elevated in urban areas around the world and how temperature and precipitation affects these inputs. We conducted a meta-analysis to compare atmospheric deposition of phosphorus in urban and rural sites across the globe. We hypothesized that atmospheric phosphorus deposition behaves similarly to atmospheric nitrogen deposition, with increased concentrations and rates of atmospheric phosphorus inputs in urban compared to nearby rural areas. We also hypothesized that the urban enhancement of atmospheric phosphorus inputs is positively influenced by mean annual temperature and precipitation. Data were compiled from 38 cities across 11 countries (i.e. Brazil, China, India, Japan, Pakistan, Spain, Taiwan, Tunisia, Turkey, Ukraine, and United States) and five continents (i.e. Africa, Asia, Europe, North America, and South America). Across the 16 cities that had paired urban and rural sites, there was not a statistically significant difference in atmospheric concentrations nor fluxes of phosphorus deposition between urban and nearby rural sites. However, we found that the difference between rates of atmospheric phosphorus deposition in urban vs. rural sites is positively related to mean annual temperature, though not total annual precipitation. Together these results demonstrate that climatic factors like temperature enhance the urbanization effect, such that sites with warmer temperatures experience a greater difference in urban vs. rural phosphorus deposition rates.

Dust Deposition at Zhurong Landing Site From Multispectral Camera Observations

AbstractDust deposition is one of the most predominant processes occurring on Mars. Until now, just a few in situ observations have been conducted to investigate the Martian dust. The Multispectral Camera (MSCam) onboard the Zhurong rover with its calibration target can be used to monitor dust deposition, providing a new ground observation. In this work, we focused on the observations of the MSCam calibration target to retrieve atmospheric optical depth and dust deposition rate over the first 300 sols. The derived atmospheric optical depths are around 0.44, suggesting relatively low airborne dust. The estimated dust deposition rate reveals a distinctive deposition process compared with that of other rovers or landers. Notably, no evident dust is presented during the initial 110 sols, after which dust starts to accumulate. Combining in situ meteorological measurements and numerical modeling, wind speed could be a critical factor to control the dust deposition rate.

Modeling atmospheric microplastic cycle by GEOS-Chem: An optimized estimation by a global dataset suggests likely 50 times lower ocean emissions

Modeling atmospheric microplastic cycle by GEOS-Chem: An optimized estimation by a global dataset suggests likely 50 times lower ocean emissions

Atmospheric Deposition around the Industrial Areas of Milazzo and Priolo Gargallo (Sicily–Italy)—Part B: Trace Elements

The concentrations of trace elements in atmospheric bulk depositions (wet plus dry) were investigated from two highly industrialised areas of Sicily (southern Italy) from June 2018 to July 2019, in order to recognise the main natural and anthropogenic sources. A side objective of this study was to improve the common sampling procedures and analytical methods used for monitoring trace elements in atmospheric deposition. The trace element VWM (Volume-Weighted Mean) concentrations ranged from less than 0.01 μg L−1 for trace elements such as Cs, Tl, and U, up to 24 μg L−1 for minor elements (Al, Zn, Sr), in the filtered aliquot, while they reached concentrations up to 144 μg L−1 for the same elements, in the unfiltered aliquot. Therefore, significant differences in concentrations between these two aliquots were found, particularly for Al, Fe, Ti, Zn, Cr, Pb, Se, Cs, and U. This implies that filtering operations may produce a consistent underestimation of concentrations of certain ‘constituents’ of the atmospheric deposition. Natural (marine spray, local and regional geogenic input, volcanic emanations) and anthropogenic sources (industrial emissions, auto vehicular traffic, and diffuse background pollution) which influence rainwater chemistry were identified. Enrichment factors (EFs), with respect to the upper crust composition, provided clear evidence of the different sources above mentioned: Ti, Fe, Al, Cs, Cr, Rb, and Co have low EFs (<1), and are referable to the (local and/or regional) geogenic input, while Se, Sb, Zn, B, Cd, Cu, Mo, Sr, As, with high EFs (>10), highlight the influence of marine and/or industrial sources. The study produced a novel dataset on the atmospheric deposition rate of several trace elements, which had never been studied in the investigated areas. Finally, a comparison of trace element deposition rates in the studied areas with the atmospheric deposition reported for 53 different sites, belonging to 20 different European nations, was made. The comparison showed that some elements, such as Al, V, Zn, and Mo had higher median deposition fluxes in the Sicilian sites than in European monitoring sites.

Atmospheric deposition of microplastics in a rural region of North China Plain

Microplastics (MPs) pollution is becoming one of the most pressing environmental issues globally. MPs in the marine, freshwater and terrestrial environments have been fairly well investigated. However, knowledge of the atmospheric-mediated deposition of MPs within rural environments is limited. Here, we present the results of bulk (dry and wet) atmospheric MPs deposition in a rural region of Quzhou County in the North China Plain (NCP). Samples of MPs in the atmospheric bulk deposition were collected for individual rainfall events over a 12-month period from August 2020 to August 2021. The number and size of MPs from 35 rainfall samples were measured by fluorescence microscopy, while the chemical composition of MPs was identified using micro-Fourier transform infrared spectroscopy (μ-FTIR). The results showed that the atmospheric MPs deposition rate in summer (892–75,421 particles/m2/day) was highest compared to 735–9428, 280–4244 and 86–1347 particles/m2/day in spring, autumn, and winter, respectively. Furthermore, the MPs deposition rates in our study were 1–2 orders of magnitude higher than those in other regions, indicating a higher rate of MPs deposition in the rural region of the NCP. MPs with a diameter of 3–50 μm accounted for 75.6 %, 78.4 %, 73.4 % and 66.1 % of total MPs deposition in spring, summer, autumn, and winter, respectively, showing that the majority of MPs in the current study were small in size. Rayon fibers accounted for the largest proportion (32 %) of all MPs, followed by polyethylene terephthalate (12 %) and polyethylene (8 %). This study also found that a significant positive correlation between rainfall volume and MPs deposition rate. In addition, HYSPLIT back-trajectory modelling showed that the farthest source of deposition MPs may have come from Russia.

Polycyclic Aromatic Hydrocarbons in the Snow Cover in the City of Tyumen (Western Siberia, Russia).

Some of Russia's large industrial cities are sources of hazardous contamination in the environment. Tyumen is one of the most rapidly developing cities in Siberia due to oil and gas extraction in the northern Tyumen Region. Concentrations of 14 polycyclic aromatic hydrocarbons (PAH)s deposited with the particulate matter (PM) of snow in the city of Tyumen were determined by liquid chromatography. In the background area, the rate of atmospheric particulate deposition was shown to be low, and the mean total content of 14 PAHs had a value of 6.2 ng L-1, which is lower than many unpolluted areas on Earth. In the city of Tyumen, the mean content of PM was five times higher and the mean total content of 14 PAHs was twenty times higher as compared to the background. The contents of chrysene, benzo(k)fluoranthene, and benzo(a)pyrene were increased by multiples of 78, 77, and 32, respectively. The rates of ∑14 PAH deposition with airborne PM over the winter ranged from 1.1 to 65.5 μg m-2. Calculations of BaP toxic equivalent showed maximal toxicity within the transport zone. Both analysis of spatial distribution and diagnostic ratios showed that the PAHs were mainly from coal combustion and vehicle emissions.

Total mercury, methylmercury, and selenium concentrations in blue marlin Makaira nigricans from a long-term dataset in the western north Atlantic

Mercury in seafood is a neurotoxicant that threatens human health. Dynamic rates of mercury emission, re-emission, and atmospheric deposition warrant studies into mercury concentrations in fish because many are consumed by humans and can serve as sentinels of mercury levels in the environment. We modeled trends in total mercury content in an apex marine fish predator, Atlantic blue marlin Makaira nigricans, whose muscle tissues were opportunistically sampled from North Carolina (USA) sportfishing tournaments over a discontinuous time period: between 1975 and 77 and 1998–2021 (n = 148). The model-estimated influence of marlin weight on total mercury concentration was constant across years (shared slope) allowing for comparisons of weight-corrected mercury concentrations among years. Weight-corrected total mercury concentrations revealed an inter-decadal decline of approximately 45 % between the 1970s and late 1990s and then variable but relatively stable concentrations through 2021. The mean (SD) wet weight concentration of total mercury was 9.47 (4.11) from 1975 to 77 and 4.17 (2.61) from 2020 to 2021. Methylmercury and selenium were measured on a subset of fish to address questions related to human health and consumption. Methylmercury levels (mean = 0.72 μg/g) were much lower than total mercury (mean = 4.69 μg/g) indicating that total mercury is not a good proxy for methylmercury in Atlantic blue marlin. Selenium, examined as a Se:Hg molar ratio and as a selenium health benefit value (HBVSe), showed high protective value against mercury toxicity. Long-term trends in the concentration of mercury in blue marlin should continue to be monitored to determine whether policies to mitigate anthropogenic contributions to global mercury are achieving their intended goals and to provide information to inform safe human consumption.

PFAS concentrations and deposition in precipitation: An intensive 5-month study at National Atmospheric Deposition Program – National trends sites (NADP-NTN) across Wisconsin, USA

Atmospheric transport and processing of per- and polyfluoroalkyl substances (PFAS) leads to deposition and accumulation of these compounds in terrestrial and aquatic ecosystems, however, measurements of PFAS flux and deposition rates remain sparse and underdeveloped. In 2020, ninety-one precipitation samples, along with an array of QA/QC samples were collected from eight National Trends Network (NTN) sites across Wisconsin through the National Atmospheric Deposition Program (NADP). Weekly precipitation samples were analyzed for a suite of 34 PFAS compounds to provide measurements of speciated PFAS concentrations and deposition fluxes to in the Upper Great Lakes Region. Perfluoro carboxylates (PFCAs) were detected most frequently and constituted an average of 83% of the total mass quantified across the samples. Summed PFAS mass concentrations in the rainwater ranged from 0.7 to 6.1 ng/L with a median of 1.5 ng/L. Daily flux values ranged from 1.3 to 47.4 ng/m2/day with a median of 5.7 ng/m2/day. From an analysis of variance (ANOVA), significant differences in the average chemical profiles (PFAS fingerprints) were observed among the 8 sampling sites, indicating that nearby sources of PFAS can potentially influence wet-deposition composition of certain species on observed spatial scales. Strict quality control measures were developed and implemented for this study to confirm that the field and laboratory methods met the necessary high data quality standards. These methods and QA/QC protocols are detailed here to provide guidance for future wet deposition sampling of PFAS. This campaign confirms the efficacy of NADP-NTN samplers and protocols for the collection and study of PFAS atmospheric transport, deposition rates, and spatial trends in concentrations and flux.

Radiocesium accumulation in Lake Kasumigaura by riverine input and migration following the Fukushima Dai-ichi nuclear power plant accident

Vertical radiocesium concentration profiles and inventories in sediments were measured in Lake Kasumigaura following the 2011 Fukushima Dai-ichi Nuclear Power Plant accident. Further measurements of radiocesium concentrations in suspended solids (SS) have been conducted since September 2012 in the Koise and Sakura rivers inflowing into the lake. Cesium-137 (137Cs) accumulated intensively near the inflow outlets in the lake. At the lake center, the 137Cs inventory in sediments increased during 2011–2014; however, few changes were observed during 2014–2016. The 137Cs surface concentration and inventory decreased considerably in Tsuchiura-iri Bay until 3 years after the accident, indicating 137Cs migration. However, the rate of decrease subsequently slowed due to the 137Cs supply from the river. The 137Cs concentration in river SS declined during 2012–2015; however, it remained 1–2 orders of magnitude above its pre-accident level. The entrainment coefficient of particulate 137Cs in the inflows was initially higher in the Koise River but decreased exponentially more rapidly in the Koise River than in the Sakura River until 2015. Therefore, in the future, the difference in 137Cs concentrations will be smaller. The 137Cs concentration in the Koise River will continue to decrease; thus, the difference in the 137Cs inventory between the northern and southern parts of the lake will decrease. Total estimated amounts of 137Cs in the entire lake were 3.72 × 1012 Bq in December 2012 and 4.18 × 1012 Bq in August 2016. The accumulated amount of 137Cs in the entire lake based on sediment analysis was similar to the riverine input of particulate 137Cs based on riverine SS analysis from December 2012‒;August 2016, confirming the high trapping performance of the lake for particulate matter provided by the basin. Moreover, the amount of 137Cs accumulated in the lake in 2016 may have originated from comparable rates of atmospheric deposition and riverine input. These findings provide useful insights for future prediction and management of radiocesium contamination and the effects of riverine inputs in general shallow lakes.

Levels of nitramines and nitrosamines in lake drinking water close to a CO2 capture plant: A modelling perspective

While CO2 capture is considered a key climate change mitigation option, we must ensure that global implementation occurs without causing harm to the local environment and the human health. The most mature option for capture is using amines, which however, is associated with a risk of contaminating nearby drinking water sources with carcinogenic nitramines (NAs) and nitrosamines (NSAs). Here we present the first process-based simulation of NAs and NSAs in a catchment-lake system with the input of previously modelled atmospheric deposition rates. Considering full-scale CO2 capture at the Oslo waste incineration plant in Norway, future (∼10 y) levels in a nearby lake approach the national drinking water limit. We further quantified the effect of hydrological and biogeochemical processes and identified those with the highest sensitivity (NA biodegradation). The uncertainty of the results is presented by a probabilistic distribution (Monte Carlo analysis), incorporating variability in catchment, lake, and literature NA and NSA parameter values. This modelling tool allows for the site-specific assessment of the abovementioned risks related to amine-based CO2 capture and aspires to contribute to the sound evaluation of costly amine emission reduction measures.