Suspended Particulate Matter Samples Research Articles

Variations in provenance and transport of terrestrial organic matter in the Changjiang River during the flood season

River is a crucial channel for the transport of terrestrial organic carbon (OCterr) into the sea, and has significant implications for the global carbon cycle. However, with the intensification of human activities within the watershed (such as dams and changes in land use), the sediment and OCterr output from rivers have significantly decreased. To study the influence of human activities on the provenance and transport of particulate organic carbon (POC) exported from the Changjiang River Basin (CRB), we collected suspended particulate matter samples during the rainy season of 2021. The POC content exhibited an increasing trend from the headwater zone to the estuary. Results of three-end-member mixing model indicated that both soil-derived and autochthonous OC (OCauto) contributed approximately more than 40.0 %. Notably, OCauto experienced a significant increase from the Three Gorges Dam (TGD) to estuary in the mainstem, attributed to the sediment interception effect of the TGD. The POC contents in the headwater zone and Jinshajiang River in 2021 were lower compared to those in 2007, which can be attributed to a decrease in cultivated land area and increase sediment trapping by cascade dams. Affected by TGD, the POC content in the middle and lower reaches as well as the delta zone first decreased in 2003 and then increased from 2007 to 2021. Additionally, the degradation of lignin phenols and n-alkanes was influenced by the TGD, which prolonged the retention time of terrestrial plants. Compared to previous studies, the decrease in soil-derived OC and increase in OCauto in CRB, influenced by dams and land use, could have long-lasting effect on carbon burial in the ECS.

Analysis of Suspended Particulate Matter in a Conventional Seed Spices Cleaning and Grading Industry: A Case Study of Unjha Vicinity in Gujarat, India

A large number of seed spices (Cumin, Fennel, Coriander, Fenugreek etc.) cleaning-grading units are situated in Gujarat and Rajasthan. In-plant study was performed in such a cleaning-grading industry located at Unjha (Gujarat) in collaboration with Centre for Research on Seed Spice (SDAU), Jagudan, Mehsana. Apprehension for wellbeing of workers of such dust/ suspended particulate matter (SPM) generating industries are growing with time. SPM samples were collected using standard High Volume Sampler and these samples were analyzed for their respirable suspended particulate matter (RSPM) and total SPM concentration (µg/m3). The highest concentration of RSPM (< 10 micron) inside the plant was found to be 20 x103 µg/m3, while the highest SPM concentration level was 168x103 µg/m3. The average particle size of SPM was 1.96 µ to 9.43 µ while that of RSPM was 1.7 µ. The Ambient air quality norms prescribed by Central Pollution Control Board (CPCB) for industrial areas limit these values to 100 µg/m3 (SPM) and 60 µg/m3 (RSPM). Such highly polluted in-plant atmosphere of seed spices cleaning-grading industry may cause severe health problems, leading to respiratory diseases among the workers. In order to protect the health of workers engaged in these industries, it is suggested to install the electrostatic precipitator (ESP) device and retrofitting of existing equipment (such that dust levels are within permissible limits) may be considered.

Source analysis and health risk assessment of polycyclic aromatic hydrocarbon (PAHs) in total suspended particulate matter (TSP) from Bengbu, China

The polycyclic aromatic hydrocarbon (PAH) concentrations in total suspended particulate matter (TSP) samples collected from October, 2021 to September, 2022 were analyzed to clarify the pollution characteristics and sources of 16 PAHs in the atmospheric TSP in Bengbu City. The ρ(PAHs) concentrations ranged from 1.71 to 43.85 ng/m3 and higher concentrations were detected in winter, followed by spring, autumn, and summer. The positive matrix factorization analysis revealed that, in spring and summer, PAH pollution was caused mainly by industrial emissions, gasoline and diesel fuel combustion, whereas in autumn and winter, it was coal, biomass and natural gas combustion. The cluster and potential source factor analyses showed that long-range transport was a significant factor. During spring, autumn, and winter, the northern and northwestern regions had a significant impact, whereas the coastal area south of Bengbu had the greatest influence in summer. The health risk assessment revealed that the annual total carcinogenic equivalent concentration values for PAHs varied from 0.0159 to 7.437 ng/m3, which was classified as moderate. Furthermore, the annual incremental lifetime cancer risk values ranged from 1.431 × 10−4 to 3.671 × 10−3 for adults and from 6.823 × 10−5 to 1.749 × 10−3 for children, which were higher than the standard.

Residual levels, phase distributions, and human health risks of OCPs in the middle reach of the Huai River, China.

Are the residues of organochlorine pesticides (OCPs) in freshwater in China still of concern after prohibition and restriction for decades? The scarcity of monitoring data on OCPs in freshwater in China over the past few years has hampered understanding of this issue. In this study, water and suspended particulate matter (SPM) samples were collected from the middle reach of the Huai River for OCP analyses. Residues of ∑OCPs in water and SPM ranged from ND to 8.6ng L-1 and 0.50 to 179ng L-1, with mean concentrations of 1.7 ± 1.3ng L-1 and 6.1 ± 31ng L-1, respectively. ∑HCHs (α-, β-, γ-, and δ-HCH) and ∑HEPTs (heptachlor and heptachlor epoxide) were the most predominant pesticides in the dissolved phase and SPM, respectively, accounting for 43 ± 35% and 27 ± 29% of ∑OCPs. HCHs and heptachlor epoxide mainly existed in the dissolved phase, while heptachlor mainly existed in SPM. The isomeric composition pattern of HCHs in water differed from that in SPM. Briefly, β-HCH dominated in water, while δ-HCH dominated in SPM. However, the composition pattern of DDT and its metabolites in water was similar to that in SPM. o,p'-DDD and p,p'-DDE dominated in both water and SPM. The ratios of α-/γ-HCH and (DDD + DDE)/DDTs indicated that HCHs and DDTs were mainly derived from historical residues. Risk assessments indicated that OCPs may not pose carcinogenic and non-carcinogenic risks to residents.

Channel cross-section heterogeneity of particulate organic carbon transport in the Huanghe

Abstract. The Huanghe (Yellow River), one of the largest turbid river systems in the world, has long been recognized as a major contributor of suspended particulate matter (SPM) to the ocean. However, over the last few decades, the SPM export flux of the Huanghe has decreased over 90 % due to the high management, impacting the global export of particulate organic carbon (POC). To better constrain sources and modes of transport of POC beyond the previously investigated transportation of POC near the channel surface, SPM samples were for the first time collected over a whole channel cross-section in the lower Huanghe. Riverine SPM samples were analyzed for particle size and major element contents, as well as for POC content and dual carbon isotopes (13C and 14C). Clear vertical and lateral heterogeneities of the physical and chemical properties of SPM are observed within the river cross-section. For instance, finer SPM carry more POC in general with higher 14C activity near the surface of the right bank. Notably, we discuss how bank erosion in the alluvial plain is likely to generate lateral heterogeneity in POC composition. The Huanghe POC is millennial-aged (4020 ± 500 radiocarbon years) and dominated by organic carbon (OC) from the biosphere, while the lithospheric fraction is ca. 12 %. The mobilization of aged and refractory OC, including radiocarbon-dead biospheric OC, from deeper soil horizons of the loess–paleosol sequence through erosion in the Chinese Loess Plateau is an important mechanism contributing to fluvial POC in the Huanghe drainage basin. Altogether, anthropogenic activities can drastically change the compositions and transport dynamics of fluvial POC, consequentially altering the feedback of the source-to-sink trajectory of a river system to regional and global carbon cycles.

Exploration of natural processes and anthropogenic inputs by Zn isotopes in suspended particulate matter: A case study from the Lancang River in Southwest China

River is an important pathway for the biogeochemical cycle of Zn. This study reports Zn concentration and δ66Zn composition for suspended particulate matter (SPM) from Lancang River basin in Southwest China, and explore the impact of natural processes and human activities on Zn cycle. The SPM samples have a much higher average Zn content (162 mg kg−1) than that of the upper crust (67.0 mg kg−1), but it is close to the value of the Pearl River (187 mg kg−1). The enrichment factor (EF) values of Zn in SPM range from 1.08 to 6.88, with an average of 2.15, which does not show significant pollution characteristics. The δ66Zn values in SPM range from −0.67‰ to +0.63‰, with an average of +0.13‰. The δ66Zn values showed positive correlation with Ca/Mg ratios while showed little correlation with Zn contents in SPM. It indicated that anthropogenic sources have limited influence on SPM, and the Zn isotope composition in SPM is more likely to be inherited from the weathered rocks materials and influenced by natural fractionation processes in river water. This result contributes to understanding of the geochemical cycling process of Zn and its environmental effects in water.

Manganese cycling and transport in boreal estuaries impacted by acidic Mn-rich drainage

As critical transition zones between the land and the sea, estuaries are not only hotspots of hydrogeochemical and microbial processes/reactions, but also play a vital role in processing and transferring terrestrial fluxes of metals and nutrients to the sea. This study focused on three estuaries in the Gulf of Bothnia. All of them experience frequent inputs of acidic and Mn/metal-rich creek waters due to flushing of acid sulfate soils that are widespread in the creekś catchments. Analyzing existing long-termwaterchemistrydata revealed a strong seasonal variation of Mn loads, with the highest values in spring (after snow melt) and autumn (after heavy rains). We sampled surface waters, suspended particulate matter (SPM), and sediments from the estuarine mixing zones and determined the loads and solid-phase speciation of Mn as well as the composition and metabolic potentials of microbial communities. The results showed that the removal, cycling, and lateral transport of Mn were governed by similar phases and processes in the three estuaries. Manganese X-ray absorption spectroscopy data of the SPM suggested that the removal of Mn was regulated by silicates (e.g., biotite), organically complexed Mn(II), and MnOx (dominated by groutite and phyllomanganates). While the fractional amounts of silicate-bound Mn(II) were overall low and constant throughout the estuaries, MnOx was strongly correlated with the Mn loadings of the SPM and thus the main vector for the removal of Mn in the central and outer parts of the estuaries, along with organically complexed Mn(II). Down estuary, both the fractional amounts and average Mn oxidation state of the MnOx phases increased with (i) the total Mn loads on the SPM samples and (ii) the relative abundances of several potential Mn-oxidizing bacteria (Flavobacterium, Caulobacter, Mycobacterium, and Pedobacter) in the surface waters. These features collectively suggested that the oxidation of Mn, probably mediated by the potential Mn-oxidizing microorganisms, became more extensive and complete towards the central and outer parts of the estuaries. At two sites in the central parts of one estuary, abundant phyllomanganates occurred in the surface sediments, but were converted to surface-sorbed Mn(II) phases at deeper layers (>3–4 cm). The occurrence of phyllomanganates may have suppressed the reduction of sulfate in the surface sediments, pushing down the methane sulfate transition zone that is typically shallow in estuarine sediments. At the outermost site in the estuary, deposited MnOx were reduced immediately at the water–sediment interface and converted most likely to Mn carbonate. The mobile Mn species produced by the Mn reduction processes (e.g., aqueous Mn(II) and ligand complexed Mn(III)) could partly diffuse into the overlying waters and, together with the estuarine Mn loads carried by the surface waters, transfer large amounts of reactive Mn into open coastal areas and subsequently contribute to Mn shuttling and inter-linked biogeochemical processes over the seafloor. Given the widespread occurrence of acid sulfate soils and other sulfidic geological materials on many coastal plains worldwide, the identified Mn attenuation and transport mechanisms are relevant for many estuaries globally.

A Comparative Study of Heavy Metal Pollution in Ambient Air and the Health Risks Assessment in Industrial, Urban and Semi-Urban Areas of West Bengal, India: An Evaluation of Carcinogenic, Non-Carcinogenic, and Additional Lifetime Cancer Cases

Air pollution is an immense problem due to its detrimental health effects on human populations. This study investigates the distribution of particle-bound heavy metals and associated health risks in three diverse areas (Durgapur as an industrial complex, Kolkata as an urban area, and Bolpur as a semi-urban region) in West Bengal, India. Twenty-one (84 samples) sampling sites were chosen, covering industrial, traffic, residential, and sensitive zones. The respirable suspended particulate matter (RSPM) samples were collected using a portable Mini-Vol Tactical Air Sampler, and heavy metal concentrations (Cd, Cr, Mn, Ni, Pb, and As) were analyzed using ICP-OES. The non-carcinogenic and carcinogenic health risks were assessed using exposure concentration (EC), hazard quotient (HQ), hazard index (HI), and additional lifetime cancer cases. The results highlight variations in heavy metal concentrations across the regions, with industrial areas exhibiting higher levels. Principal component analysis (PCA) unveiled distinct metal co-variation patterns, reflecting sources such as industrial emissions, traffic, and natural contributors. The sum of non-carcinogenic risks (HI) of all heavy metals exceeded the US EPA’s risk limit (HI<1) in both Kolkata and Durgapur, except for Bolpur. Similarly, the sum of cancer risk in three distinct areas exceeded the USEPA limits (1.00E-06). The Monte Carlo simulation revealed the 5th and 95th percentile range of cancer risk was 9.12E-06 to 1.12E-05 in Bolpur, 3.72E-05 to 4.49E-05 in Durgapur and 2.13E-05 to 2.57E-05 in Kolkata. Kolkata had the highest additional lifetime cancer cases compared to Bolpur and Durgapur. This study provides information on the complex connections between heavy metal pollution and possible health risks in industrial, urban, and semi-urban regions.

Occurrence, distribution, and environmental risk of 61 glucocorticoids in surface water of the Yellow River Delta, China

Glucocorticoids (GCs), as important endocrine disrupting compounds and emerging contaminants, could have irreversible adverse effects on aquatic organisms even at ng/L levels. However, previous studies have only focused on the dissolved concentrations of GCs in the water, and limited data are available for their occurrences in the solid phase. In this study, the occurrence, distribution, and environmental risks of 61 natural and synthetic GCs in surface water of the Yellow River Delta (YRD) were simultaneously analyzed by investigating water, suspended particulate matter (SPM) and sediment samples at 64 sites in six major rivers in the wet season. Overall, 51 GCs were detected in all samples from different matrices, and their concentrations were in the range of not detected (ND)−274 ng/L in water, ND−42 ng/g dry weight (dw) in SPM and ND−9.98 ng/g dw in sediment. Natural GCs were the dominant compounds in all samples, followed by synthetic halogenated esters. High concentrations of GCs were observed in discharge outlet samples from livestock farming, aquaculture and industrial production, and the composition differences of GCs between human/animal sources and industrial sources could be used as indicators to identify pollution sources. Most GCs were distributed in the water phase, while compounds with higher log octanol/water partition coefficients (log Kow) tended to be adsorbed to SPM and sediment. The spatial distribution of GCs was primarily affected by anthropogenic activities and hydrodynamic conditions. Four synthetic compounds (budesonide [BD], fluocinolone acetonide [FOA], fluticasone propionate [FP], and clobetasol propionate [CBSP]) were identified as the main contributors to GC activity with a combined contribution of 57 %–95 %. Risk assessment using the risk quotient revealed that low to moderate risks are posed to aquatic organisms in surface water.

Atmospheric Transport of Adulticides Used to Control Mosquito Populations across an Urban Metropolitan Area

Pesticides registered with the U.S. EPA for mosquito control are called adulticides and are released directly into the atmosphere as aerosols to target flying mosquitos. This adulticide application approach is different from traditional (agricultural) pesticide applications, yet the fate and transport of adulticides in large metropolitan areas is largely unknown. The Houston Metropolitan Area encompasses eight counties, many of which require county-level mosquito control programs that utilize adulticides. Malathion and permethrin are the primary adulticides used by Harris County (HC) in Houston, TX, USA. Houston, like many other metropolitan areas, has an urban atmosphere supporting the oxidation of both gas and particle phase pollutants. During the summer mosquito season of 2016, we collected atmospheric total suspended particulate matter (PM) samples at Jones Forest (JF), located in Montgomery County (directly north of HC) to investigate the atmospheric transport and oxidation of adulticides in an urban atmosphere. Despite HC alternating the adulticide treatment schedule, we measured permethrin, malathion, and malaoxon (oxidation product of malathion), throughout the sampling campaign. These consistent measurements, in conjunction with 12 h backward trajectories, support the conclusion that JF is influenced by other county-level mosquito-control programs and agricultural pesticide use. This cross-county transport may impact adulticide effectiveness by supporting pesticide resistance in mosquito populations due to repeated exposures to pesticides. This study highlights the need for mosquito control collaborations between counties, especially in areas of urban expansion overlapping with agricultural activities.

Bee Pollinator Mortality Due to Pesticide-Laden Particulate Matter from Beef Cattle Feedyards.

Wild and managed bees are critical for the stability of trophic webs, angiosperm reproduction, and agricultural productivity. Unfortunately, as many as 40% of crop pollinators are in a steep decline due to habitat loss and exposure to agrochemicals. Pyrethroids, neonicotinoids, and macrocyclic lactones are among the many agrochemicals toxic to pollinating insects that are used extensively in industrial beef cattle feeding operations throughout the world. Fugitive feedyard particulate matter (PM) transports agrochemicals into the surrounding environs. To determine the impact of agrochemical-laden feedyard particulate matter on bee pollinators, we conducted in situ experiments wherein honeybees and mason bees were placed downwind and upwind of feedyards (N = 40). Concurrent, colocated total suspended particulate matter samples contained multiple insecticides and parasiticides including pyrethroids, neonicotinoids, and macrocyclic lactones, in significantly higher concentrations downwind of feedyards (bifenthrin, 8.45 ± 4.92; permethrin, 1032.34 ± 740.76; clothianidin, 3.61 ± 1.48; imidacloprid, 73.32 ± 47.52; thiamethoxam, 5.81 ± 3.16; abamectin, 0.45 ± 0.29; ivermectin, 8.88 ± 5.06 ng/g). Honeybees and mason bees sited downwind of feedyards always experienced higher mortality than those correspondingly sited upwind, and male mason bees experienced significantly higher mortality compared to females when both were sited downwind. Bees occurring downwind of beef cattle feedyards for 1 h are 232-260% more likely to die than those occurring upwind. Thus, agrochemicals used on and emitted from beef cattle feedyards are significant threats to bee pollinators.

Composition and sources of suspended particles in the Pacific Arctic region

During the 6th (2014) and 7th (2016) Chinese Arctic Expedition (CHINARE), samples of suspended particulate matter (SPM) were collected from both surface (depth: <1.0 m) and subsurface (depth: approximately between 10 and 150 m) waters over the northern shelf of the Bering Sea and in the western Arctic Ocean. To investigate the distribution and sources of organic matter in both the surface water and the vertical profile, the concentration and stable carbon isotopic composition of SPM, particulate organic carbon (POC), and particulate nitrogen (only in surface water samples) were determined, and some particle samples were selected for examination using scanning electron microscopy. Results showed apparent geographical partitioning and temporal variation in both the concentration and the composition of SPM. Higher SPM concentrations were observed in nearshore, shelf break, and sea ice edge areas; the distribution of POC concentration displayed a similar pattern, with higher values found from the northern part of the Bering Shelf to southern parts of the Chukchi Shelf. In surface water, SPM mainly comprised clay and detrital minerals with higher POC contents, lighter δ13C values, and higher POC/PN ratios, indicating organic matter predominantly derived from terrestrial sources in areas south of St. Lawrence Island and north of 73°N. The downward trend of heavier δ13C values, together with reduction in clay and detrital minerals, suggests that vertical transport of SPM is hindered by stratification, resulting in transport of terrestrial materials toward northern basin areas. In the Chukchi Slope and Canada Basin areas, extremely light δ13C values (as low as −33.41‰ PDB) were mainly observed at depths of 20–60 m, where the Polar Mixed Layer (PML) intersects with the Upper Halocline Layer (UHL). Under the condition of low sea ice extent in 2016, the POC-δ13C values were heavier in the PML than in the UHL in the Chukchi Slope and Canada Basin areas. These findings provide insights into the sources, transport, and fate of organic matter in the Pacific Arctic region, which have important implications for understanding the biogeochemical cycles and ecosystem dynamics in this remote and rapidly changing environment.

Investigation of organochlorine pesticides in the Wang Lake Wetland, China: Implications for environmental processes and risks

Wang Lake Wetland is an important habitat for many fish and migratory birds. To explore the effect of periodic hydrological changes on the transfer and ecological risk of OCPs in the multimedia system of the wetland, eight sampling sites were selected for collecting soil (SS), sediment (SD) and water, to acquire dissolved phase (DP) and suspended particulate matter (SPM) samples during low- and high-flow periods. The results indicated that OCPs are pervasive in the various media of Wang Lake Wetland, and there was a significant temporal variability in concentration of ∑23OCPs in the SPM samples. Several OCPs exist certain ecological risks to aquatic organisms, but higher level of OCPs do not always equal to higher ecological risk. The residues of OCPs are largely attributed to their historical use, but recent inputs of some of them are still non-ignorable. The relatively higher values of organic carbon normalized partition coefficient (KOC) for SPM-W (KOC(SPM-W)) were obtained, which reflected the more frequent exchange of OCPs in the SPM samples. The sediment of the Wang Lake Wetland is likely to be a sink for several OCPs with high n-octanol/water partition coefficient (KOW) (e.g., DDTs and its metabolites), and high-temperature and rainfall-driven changes may promote the migration of OCPs with low KOW to the DP.

Efficiency of five samplers to trap suspended particulate matter and microplastic particles of different sizes

Suspended particulate matter (SPM) plays a major role in nutrient cycles and for the transport of pollutants within local and transboundary water catchments. Obtaining representative SPM samples from rivers, lakes, inland and coastal waters is crucial for quantitative and qualitative chemical analyses to correctly describe the chemical status of a water body. However, a representative sampling of SPM over time is challenging due to the heterogeneity of SPM particles sizes, their non-uniform distribution in rivers, and a variety of sampling devices being in use. Therefore, we investigated the efficiencies of five different sampling devices commonly used in national and international monitoring programs to collect representative SPM samples. We tested three passive sedimentation-based samplers (SBSs: sedimentation box, SB; sedimentation tank, ST; Raetz Sampler, RS), and two active separation techniques (continuous flow centrifuge, CFC; vacuum filtration, VF) in an experimental laboratory setup using in-house SPM standard suspensions (mineral, organic, and microplastic particles) with defined particle sizes. The mass-based efficiencies of the three examined SBSs were 0–66% for the mineral and organic particles <75 μm, where the mean particle sizes of collected samples were always shifted to bigger sizes compared to the initial suspensions. The efficiencies of the three SBSs to collect microplastic particles <80 μm were <20% due to the lower densities of microplastic compared to organic and mineral particles. In contrast to the SBSs, VF and CFC units showed excellent efficiencies >86% for all tested materials, with similar particle size distributions of the sampled material compared to those of the inlet suspensions. In conclusion, SPM sampling efficiencies of sampling units have to be carefully considered and compared to the respective aims of the monitoring approaches, especially when statements are derived from quantitative results on SPM.

Tracking down unknown PFAS pollution – The direct TOP assay in spatial monitoring of surface waters in Germany

PFAS contamination of surface waters in central Europe was investigated in a spatial monitoring using suspended particulate matter and sediment samples. The samples were collected in 2021 at 171 sampling sites in Germany and at five sites in Dutch waters. All samples were analyzed for 41 different PFAS by target analysis to establish a baseline for these compounds. In addition, a sum parameter approach (direct Total Oxidizable Precursor (dTOP) assay) was used to investigate the PFAS load in the samples more comprehensively.PFAS pollution varied widely between water bodies. Target analysis detected ∑PFAS concentrations between <0.5 and 53.1 μg kg−1 dry weight (dw), while levels of <1.0–337 μg kg−1 dw were determined by dTOP assay. Associations were observed for ∑PFSAdTOP and the percentage of urban area in the vicinity of the sampling sites and, less strongly, for distances to industrial sites (i.e. galvanic/paper) and airports. PFAS hotspots were identified by setting the 90th percentile of the data sets for ∑PFAStarget or ∑PFASdTOP as a threshold. Of the 17 hotspots identified by target analysis or dTOP assay, respectively, there were only six overlaps. Thus, 11 highly contaminated sites could not be identified by classical target analysis.The results demonstrate that target analysis captures only a fraction of the actual PFAS load, while unknown precursors remain undetected. Consequently, if only the results of target analysis are considered in assessments, there is a risk that sites heavily polluted with precursors will not be identified delaying mitigation actions and risking prolonged negative impacts on human health and ecosystems. Moreover, effective PFAS management requires establishing a baseline for PFAS using target and sum parameters such as the dTOP assay, and then monitoring this baseline on a regular basis to support emission control and to inform risk management of its effectiveness.

Impacts of shipyard oil leakage on the PAHs and PCBs occurrence in Xiangshan Bay, China

Here, we studied the shipyard impacts on the distribution of PAHs and PCBs in the semi-enclosed Xiangshan Bay, an important mariculture zone in China. The results showed that the shipyard caused a pollution plume for PAHs but not for PCBs. As characteristic pollutants of oil leakage, the PAHs had concentrations of up to 55.82 ng L−1 in the water, 2235.04 ng g−1 in suspended particulate matter (SPM), and 1489.60 ng g−1 in sediment. The PAHs in water and SPM were dominated by phenanthrene and pyrene that were mostly derived from lubricant and diesel, while those in sediments were dominated by the high-molecular-weight PAHs, such as indeno[1,2,3-c,d]pyrene. In contrast, the PCBs concentrations reached up to 10.17 ng L−1, 79.72 ng g−1, and 124.33 ng g−1 in the seawater, SPM, and sediment samples, respectively, and they did not show spatial patterns affected by the shipyard. Moreover, the health risk assessment indicated that the shipyard discharge caused a substantial PAHs ecological risk to the adjacent and downstream water environment. Therefore, point source discharge in semi-enclosed bays should be paid close attention to due to the strong pollutant transport effect.

Comparison of sedimentary iron speciation obtained by sequential extraction and X-ray absorption spectroscopy

Iron (Fe) speciation in marine sediments and suspended particulate matter (SPM) are widely used to investigate the role of Fe minerals in marine biogeochemical cycling and to reconstruct paleo-redox conditions. A traditional method for the determination of Fe speciation are sequential extractions, in which operationally defined Fe pools are dissolved by specific extraction solutions. More recently, many studies make use of synchrotron radiation-based X-ray absorption near edge spectroscopy (XANES), especially if little sample material is available or a high spatial resolution is required. However, few studies have systematically compared Fe speciation obtained by the two methods. Here, we report Fe speciation for marine sediments (both wet and freeze-dried) and SPM from contrasting marine environments (western Baltic Sea and Amazon shelf) obtained by sequential extraction and XANES. The two methods yield comparable results regarding the approximate proportion of reactive Fe ((oxyhydr)oxide, carbonate and sulfide minerals) in the total Fe pool and the extent to which reactive Fe minerals have been converted to pyrite. However, methodological issues associated with both approaches complicate a direct comparison of specific mineral groups. Pyrite concentrations obtained by XANES are lower than those obtained by extraction, which is attributed to an underestimation by XANES due to self-absorption effects and an overestimation by the chromium reduction method due to dissolution of reduced sulfur phases that are not associated with Fe. As substantial amounts of pyrite are oxidized during freeze-drying and sample storage, we recommend to analyze wet sediments in modern marine environments. The XANES spectra of Fe (oxyhydr)oxide and Fe(III)-containing (ferric) clay minerals are similar, which is why these components cannot be differentiated by XANES. Similarly, sequential extraction schemes are known to dissolve a variable proportion of ferric clay minerals along with Fe carbonates and Fe (oxyhydr)oxides. Further investigating the role of ferric clay minerals in the low-temperature marine Fe cycle may therefore require the use of additional methods. Our findings may help to assess the transferability of XANES-based Fe speciation for small sediment and SPM samples to those reported in more traditional studies on Fe biogeochemical cycling and paleo-redox conditions.

Quantification and characterization of PFASs in suspended particulate matter (SPM) of German rivers using EOF, dTOPA, (non-)target HRMS

In this study, we compare analytical methods for PFAS determination–target analysis, non-target screening (NTS), direct total oxidizable precursor assay (dTOPA) and extractable organically bound fluorine (EOF). Therefore, suspended particulate matter (SPM) samples from German rivers at different locations in time series from 2005 to 2020 were analyzed to investigate temporal and spatially resolved trends. In this study 3 PFAS mass balances approaches were utilized: (i) PFAA target vs. PFAS dTOPA, (ii) PFAS target vs. EOF and (iii) PFAS target vs. PFAS dTOPA vs. organofluorines NTS vs. EOF. Mass balance approach (i) revealed high proportions of precursor substances in SPM samples. For the time resolved analysis an increase from 94% (2005) to 97% in 2019 was observable. Also for the spatial resolved analysis precursor proportions were high with >84% at all sampling sites. Mass balance approach (ii) showed that the unidentified EOF (uEOF) fraction increased over time from 82% (2005) to 99% (2019). Furthermore, along the river courses the uEOF increased. In the combined mass balance approach (iii) using 4 different analytical approaches EOF fractions were further unraveled. The EOF pattern was fully explainable at the sampling sites at Saar and Elbe rivers. For the time resolved analysis, an increased proportion of the EOF was now explainable. However, still 27% of the EOF for the time resolved analysis and 25% of the EOF for the spatial resolved analysis remained unknown. Therefore, in a complementary approach, both the EOF and dTOPA reveal unknown gaps in the PFAS mass balance and are valuable contributions to PFAS risk assessment. Further research is needed to identify organofluorines summarized in the EOF parameter.

Polybrominated diphenyl ethers in water, suspended particulate matter, and sediment of reservoirs and their tributaries in Shenzhen, a mega city in South China.

Urban reservoirs serve many purposes including recreation and drinking water, and larger bodies of water can alter the surrounding air temperatures, making urban areas cooler in summer and warmer in winter. However, reservoirs may also be sinks for contaminants. One such group of contaminants, the polybrominated diphenyl ethers (PBDEs), are persistent organic pollutants known to accumulate in sediments and suspended particulate matter (SPM). Few studies have been conducted on PBDEs in water, SPM, and sediment from reservoirs of Shenzhen which is a mega city in South China. To this end, 12 PBDEs were measured in water, SPM, and sediment samples during the dry season (DS) and wet season (WS), to explain the spatiotemporal distribution, congener profiles, sources, and risks of pollutants in four reservoirs (A-D) and their tributaries in the study region. The concentration of ∑12PBDEs during the DS was found to be significantly higher than that during the WS. Source apportionment suggested that commercial penta-, octa-, and deca-BDEs are the major components of PBDEs, resulting mainly from atmospheric deposition, wastewater discharge, and external water-diversion projects. Further, attention should be paid to electronic equipment manufacturing factories in the study area. Risk assessment indicated risk of PBDEs (especially BDE-209) in sediment and SPM to be of concern. This study provides important data support for the control of PBDEs in natural drinking water sources.

Broadening the lens on bisphenols in coastal waters: Occurrence, partitioning, and input fluxes of multiple novel bisphenol S derivatives along with BPA and BPA analogues in the Pearl River Delta, China

Bisphenol S derivatives (BDs) are being widely used as novel substitutes for BPA and BPA analogues (BPAs), causing pollution in various environmental compartments. However, the occurrence and fate of BDs in coastal waters are currently unknown. To broaden the lens on bisphenols in coastal waters, this study measured a broad suite of 23 bisphenols, including 12 BDs along with BPA and 10 BPAs, in water, suspended particulate matter (SPM), and sediment from eight major outlets of the Pearl River Delta, China (PRD). In addition to BPA and BPAs, all the 12 BDs were detected in the collected samples. The total concentration of 12 BDs ranged from 1.2 to 25 ng/L (median of 4.3 ng/L) in water samples, 0.80–13 ng/g dw (median of 3.0 ng/g dw) in SPM samples and 0.48–3.7 ng/g dw (median of 0.64 ng/g dw) in sediment samples. For most individual BDs, they had comparable concentrations to individual BPAs. In addition, logKd values of the frequently detected bisphenols, including BPA, BPS, BPF, 4-((4-Isopropoxyphenyl)sulfonyl)phenol (BPSIP), 2,4-bis(phenylsulfonyl)phenol (DBSP), and other 9 bisphenols, were significantly correlated with their logKow values (R2 = 0.38, p < 0.05), indicating that the partitioning of bisphenols between the aqueous and SPM phases were strongly influenced by hydrophobic interaction. Based on bisphenols’ concentrations in water from the eight outlets of PRD, the estimated input fluxes of novel BDs (1900 kg/y) were found to be even higher than that of BPAs (550 kg/y). This indicates that the riverine input of BDs into the coastal environment is gradually increasing, which should be taken seriously in the future.