Late Holocene echinoderm assemblages can serve as paleoenvironmental tracers in an Antarctic fjord.

High Latitude fjords can serve as sediment trap, bearing different type of proxies, from geochemical to micropaleontological ones, making them exceptional tools for paleoenvironmental reconstruction. However, some unconventional proxies can be present and can be used to depict a comprehensive and exhaustive interpretation of past changes. Here, studying a sediment core in Edisto Inlet (Ross Sea, Antarctica) we used irregular echinoid spines and ophiuroids (Ophionotus victoriae) ossicles to trace environmental changes throughout the last 3.6 kyrs BP. Irregular echinoids can serve as proxy for the organic matter content, while O. victoriae ossicles can be used as proxy for steady sea-ice cycle along with organic deposition events. O. victoriae release a high number of ossicles, making estimation about the population quite challenging; still, presence data, can be easily collected. By applying Generative Additive Models to the stratigraphical distribution of these data, we detected an environmental phase that was previously unnoticed by other traditional proxies: the Ophiuroid Optimum (2-1.5 kyrs BP). In conclusion, here we demonstrate how echinoderm presence can be used as a valuable source of information, while proving the potential of modelling binary data to detect long-term trend in Holocene stratigraphical records.

Sedimentary biomarkers and bone specimens reveal a history of prehistoric occupation on Somerset Island (Arctic Canada).

Archaeological studies of pre-historic Arctic cultures are often limited to artefacts and architecture; such records may be incomplete and often do not provide a continuous record of past occupation. Here, we used lake sediment archives to supplement archaeological evidence to explore the history of Thule and Dorset populations on Somerset Island, Nunavut (Canada). We examined biomarkers in dated sediment cores from two ponds adjacent to abandoned Thule settlements (PaJs-3 and PaJs-13) and compared these to sediment cores from two ponds without past human occupation. Coprostanol and epicoprostanol, δ15N measurements, sedimentary chlorophyll a and the ratio of diatom valves to chrysophyte cysts were elevated in the dated sediment profiles at both sites during Thule and Dorset occupations. Periods of pronounced human impact during the Thule occupation of the site were corroborated by 14C-dated caribou bones found at both sites that identified intense caribou hunting between ca 1185 and 1510 CE. Notably, these sediment core data show evidence of the Dorset occupation from ca 200 to 500 CE at sites where archaeological evidence was heretofore lacking. We highlight the utility of lake sediments in assisting archaeological studies to better establish the timings, peak occupations and even lifestyle practices of the Dorset and Thule Arctic peoples.

Lipid biomarker profile of the Permian organic-rich shales (Irati Formation) in the northernmost of Parana Basin, Brazil.

The Irati Formation (Paraná Basin) is a mixed carbonate and organic-rich shale sequence intruded by Jurassic-Cretaceous basic rocks, featuring Brazil's most important oil shale deposits with different maturity levels. For the first time, the distribution of oil shale biomarkers from an outcrop section (quarry) of the Irati Formation in the northernmost Paraná Basin was analyzed by GC-MS and GC-MS/MS to determine the thermal evolution, organic matter origin and the depositional paleoenvironment. The organic-rich shale at the northernmost border of the basin has high similarity with the central and southernmost areas, indicating a primary control able to induce cyclic sedimentation in a broad (106 km2) and restricted environment. PCA and HCA analysis of bulk and molecular parameters showed changes in the organic matter composition and paleoenvironmental conditions throughout the stratigraphic column. Nonetheless, there are significant differences compared to the central-eastern and southern areas of the basin. Contrasting with the southern region, the north, predominates biphytane, low and medium gammacerane index. Pr/n-C17, Ph/n-C18, HI and OI values suggest type II/III kerogen from marine organic matter with freshwater input. Among the steranes, those of stereochemistry ααα 20R predominate over ααα 20S, and the presence of ßTm indicates the shales are less thermally evolved.

Determining the abundance, composition and spatial distribution of organohalogens in marine sediments using combustion-ion chromatography.

Understanding the distribution of halogenated organic compounds (HOCs) in marine sediments is essential for understanding the marine carbon and halogen cycling, and also important for assessing the ecosystem health. In this study, a method based on combustion-ion chromatography was developed for determination of the composition and abundance of HOCs in marine sediments. The method showed high accuracy, precision and reproducibility in determining the content of adsorbable organic halogens (AOX), including fluorine, chlorine and bromine (AOF, AOCl, AOBr) and the corresponding insoluble organic halogens (IOF, IOCl, IOBr, IOX), as well as total organic halogen contents (TOX). Application of the method in coastal and deep-sea sediments revealed high ratios of organic halogens in the organic carbon pool of marine sediments, suggesting that organic halogen compounds represent an important yet previously overlooked stock of carbon and energy in marine sediments. Both the TOX and the proportion of organohalogens in organic carbon (X:C ratio) showed an increasing trend from the coast to the deep-sea sediments, indicating an increased significance of HOCs in deep-sea environments. The developed method and the findings of this study lay the foundation for further studies on biogeochemical cycling of HOCs in the ocean.

Design of a sensor to estimate suspended sediment transport in situ using the measurements of water velocity, suspended sediment concentration and depth.

- The sediment transport plays a major role in every aquatic ecosystem. However, the lack of instruments to monitor this process has been an obstacle to understanding its effects. We present the design of a single sensor built to measure water velocity, suspended sediment concentration and depth in situ, and how to associate the three variables to estimate and analyse sediment transport. During the laboratory calibrations, the developed instrument presented a resolution from 0.001 g/L to 0.1 g/L in the 0-12 g/L range for the measurement of suspended sediment concentration and 0.05 m/s resolution for 0-0.5 m/s range and 0.001 m/s resolution for 0.5-1 m/s range for the measurement of water velocity. The device was deployed for 6 days in an estuarine area with high sediment dynamics to evaluate its performance. During the field experiment, the sensor successfully measured the tidal cycles and consequent change of flow directions, and the suspended sediment concentration in the area. These measurements allowed to estimate water discharge and sediment transport rates during the different phases of tides, and the daily total volume of water and total amount of sediment passing through the estuary.

Evaluating the quality of sediments in streams draining contrasting land-use areas in Osogbo metropolis, southwestern Nigeria.

The attendant effects of urbanization on the environment and human health are evaluable by measuring the potentially harmful element (PHE) concentrations in environmental media such as stream sediments. To evaluate the effect of urbanization in Osogbo Metropolis, the quality of stream sediments from a densely-populated area with commercial/industrial activities was contrasted with sediments from a sparsely-populated area with minimal anthropogenic input.Forty samples were obtained: 29 from Okoko stream draining a Residential/Commercial Area (RCA, n = 14) and an Industrial Area (IA, n = 15), and 11 from Omu stream draining a sparsely-populated area (SPA). The samples were air-dried, sieved to < 75 micron fraction, and analysed for PHEs using inductively-coupled plasma atomic emission spectrometry (ICP-AES). Index of geoaccumulation (Igeo), pollution index (PI), ecological risk factor (Er) and index (ERI) were used for assessment. Inter-elemental relationships and source identification were done using Pearson's correlation matrix and principal component analysis (PCA).PHE concentrations in the stream sediments were RCA: Zn > Pb > Cu > Cr > Sr > Ni > Co, IA: Zn > Cr > Ni > Co > Pb > Cu > Sr and SPA: Zn > Co > Cr > Cu > Sr > Ni > Pb. Igeo calculations revealed moderate-heavy contamination of Cu, Pb and Zn in parts of RCA, moderate-heavy contamination of Zn in IA while SPA had moderate contamination of Co and Zn. PI values revealed that stream sediments of RCA are extremely polluted, while those of IA and SPA are moderately and slightly polluted, respectively.The pollution of the stream sediments in RCA and IA is adduced to anthropogenic activities like vehicular traffic, automobile repairs/painting, blacksmithing/welding and metal scraping. In SPA however, the contamination resulted from the application of herbicides/fertilizers for agricultural purposes.

Distribution, sources and ecological risks of PAHs and n-alkanes in water and sediments of typically polluted estuaries: Insights from the Xiaoqing River.

Seasonal water and sediment samples were collected from the Xiaoqing River estuary and the neighboring sea to study the spatial and temporal distributions, sources and ecological risks of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes. The results showed significant spatial and temporal differences in the concentrations of PAHs and n-alkanes under the influence of precipitation, temperature, and human activities. The concentrations of PAHs in water were lower in the wet season than in the dry season, and those in sediments were higher in the wet season than in the dry season. The concentrations of n-alkanes were higher in the rainy season than in the dry season for both water and sediments. The spatial distributions of PAHs and n-alkanes were estuarine > offshore. The concentration ranges of ∑PAHs in water and sediments were 230.66-599.86 ng/L and 84.51-5548.62 ng/g, respectively, in the wet season and 192.46-8649.55 ng/L and 23.39-1208.92 ng/g, respectively, in the dry season. The proportion of three-ring PAHs in water (57.03% and 78.27% in the wet and dry seasons, respectively) was high, followed by two-ring PAHs (27.31% and 13.59% in the wet and dry seasons, respectively). The proportion of four-ring PAHs was higher in sediments (24.79% and 32.20% in the wet and dry seasons, respectively). The ecological risk of PAHs assessed using the toxicity equivalent quotient and risk quotient was at moderate to moderately high risk levels. The high concentration of n-alkane fraction C16 (611.65-75594.58 ng/L) in the water is indicative of petroleum or other fossil fuel inputs. The main peaks of n-alkanes in river sediments were C27, C29 and C31, indicating higher inputs of plant sources. The sediments in the estuary showed dominance of both short-chain C16 and long-chain C25-C31, indicating a combined input of higher plants and petroleum. The diagnostic ratios of PAHs and n-alkanes indicated that their sources were mainly oil/coal/biomass combustion and petroleum spills attributed to frequent vehicular, vessel and mariculture activities. Given the potential ecological risks of PAHs and n-alkanes in water and sediments, future studies should focus on their bioaccumulation and biotoxicity.

Assessment of microplastics and associated ecological risk in the Hirakud Reservoir, Odisha, India.

Microplastic has emerged as a global threat owing to its chronic ubiquity and persistence. Microplastics' small size expedites their ingestion at each trophic level causing biomagnification and bioaccumulation, which has raised public concerns. The present study isolated, quantified and characterized the abundance, shape, size, color, and chemical composition of the microplastics from water and sediments of the Hirakud Reservoir through a scanning electron microscope and FTIR. The ecological risk associated with the microplastics was assessed using the species sensitivity distribution (SSD) method to derive the Predicted No-Effect Concentration (PNEC) value and risk quotient (RQ). The abundance of microplastics in the surface water and sediments of the Hirakud Reservoir was estimated at 82-89 particles/L and 159-163 particles/kg, respectively. Fiber-shaped microplastics dominated both surface water (46.21%) and sediment samples (44.86%). Small-sized microplastics (53-300 µm) prevailed in all samples. Color delineation exhibited an abundance of transparent microplastics. Chemical characterization indicated the dominance of polypropylene (38%), followed by high-density polyethylene, low-density polyethylene, and polystyrene. The calculated PNEC value was 3,954 particles/m3, and the RQ was estimated to be 0.02073-0.04122 indicating negligible ecological risk to freshwater species in all the sampling sites.

Barnacle analysis as a microplastic pollution bioindicator on the East Coast of Surabaya.

Background: Plastic pollution is a significant issue on the East Coast of Surabaya, emphasizing the need to develop microplastic monitoring programs. Barnacles became one of the potential microplastic bioindicator species on the East Coast of Surabaya. This study aimed to characterize the visual and polymers of microplastics found in barnacles and assess their potential as a bioindicator species for microplastic pollution on the East Coast of Surabaya. Methods: Microplastic polymer analysis was performed using ATR-FTIR. Results: A total of 196 microplastic particles were found in barnacles, water, and sediment. The size of microplastics in barnacles, water, and sediment varied, with the size in barnacles dominated by class 1 (1-10 µm), in water by class 2 (10-50 µm), and in sediments by class 3 (50-100 µm). Fragments dominated the shape of microplastics in barnacles, while water and sediment were dominated by fiber. The microplastic color in barnacles, water, and sediment was dominated by blue, and the microplastic polymer composition on barnacles, water, and sediments was dominated by cellophane (36%). Amphibalanus amphitrite was found to be predominant and identified as a potential microplastic bioindicator because it is a cosmopolitan species. Its population was found to correlate positively with cellophane (CP) accumulation. The Pearson's correlation test between barnacle length and microplastic length at a = 0.05 was inversely proportional to r =  - 0.411 (p < 0.05), categorized as a strong enough correlation. These findings are essential in developing monitoring programs and mitigating the impact of microplastics on the marine environment.

Characteristics of minerals and oxide compounds in sediment collected from blood cockle culture areas at Bandon Bay, Thailand.

Bandon Bay is a very fertile bay for coastal aquaculture, especially for blood cockles (Anadara granosa). Its structural pattern supports the flow of nutrients which directly sent from many rivers resulted the high production capacity of blood cockle at the top level in the country. Besides organic compounds present in sediment, inorganic substances are essential for growth, survival and shell development of blood cockles. A comparative study of minerals and oxide compounds which accumulated in the sediments at eight stations around the cockle culture area was conducted. These stations are located along the estuaries at Tha Thong, Tha Chang, Phum Riang, and Tapi. The proportion of oxide compounds were determinedusing X-Ray Fluorescence (XRF) technique and minerals were analyzed by Atomic Absorption Spectroscopy (AAS). Results showed that sediment characteristics, oxide composition and the amount of minerals among the stations are different from each other. The sediments of the eastern and the western coasts were characterized as crumble clay and muddy sand, respectively. Twelve types of oxide compounds, namely SiO2, Al2O3, Fe2O3, K2O, Cl, MgO, Na2O, SO3, CaO, TiO2, MnO, P2O5 were found in various quantities, with SiO2, Al2O3, and Fe2O3 were the fundamental minerals ranging from 85.64-90.82%. Tha Thong estuary in the east coast showed highly significant quantities (P<0.05) of potassium, calcium and manganese compared to the other estuaries.

Elevated lead mobility in sediments of a eutrophic drinking water reservoir during spring and summer seasons: Insights from isotopic signatures.

Lead (Pb) pollution in sediments remains a major concern for ecosystem quality due to the robust interaction at the sediment/water interface, particularly in shallow lakes. However, understanding the mechanism behind seasonal fluctuations in Pb mobility in these sediments is lacking. Here, the seasonal variability of Pb concentration and isotopic ratio were investigated in the uppermost sediments of a shallow eutrophic drinking lake located in southeast China. Results reveal a sharp increase in labile Pb concentration during autumn-winter period, reaching ∼ 3-fold higher levels than during the spring-summer seasons. Despite these fluctuations, there was a notable overlap in the Pb isotopic signatures within the labile fraction across four seasons, suggesting that anthropogenic sources are not responsible for the elevated labile Pb concentration in autumn-winter seasons. Instead, the abnormally elevated labile Pb concentration during autumn-winter was probably related to reduction dissolution of Fe/Mn oxides, while declined labile Pb concentration during spring-summer may be attributed to adsorption/precipitation of Fe/Mn oxides. These large seasonal changes imply the importance of considering seasonal effects when conducting sediment sampling. We further propose a solution that using Pb isotopic signatures within the labile fraction instead of the bulk sediment can better reflect the information of anthropogenic Pb sources.

Multidimensional occurrence and diet risk of emerging contaminants in freshwater with urban agglomerations.

Freshwater systems near highly urbanized areas are extremely susceptible to emerging contaminants (ECs), yet their stereoscopic persistence in aquatic ecosystems and related risks remain largely unknown. Herein, we characterized the multi-mediums distribution of 63 ECs in Baiyangdian Lake, the biggest urban lake in the North of China. We identified variations in the seasonal patterns of aquatic EC levels, which decreased in water and increased in sediment from wet to dry seasons. Surprisingly, higher concentrations and a greater variety of ECs were detected in reeds than in aquatic animals, indicating that plants may contribute to the transferring of ECs. Source analysis indicated that human activity considerably affected the distribution and risk of ECs. The dietary risk of ECs is most pronounced among children following the intake of aquatic products, especially with a relatively higher risk associated with fish consumption. Besides, a comprehensive scoring ranking method was proposed, and 9 ECs, including BPS and macrolide antibiotics, are identified as prioritized control pollutants. These findings highlight the risks associated with aquatic ECs and can facilitate the development of effective management strategies.

Persistence of dissolved organic matter in sediments influenced by environmental factors：Implication for nutrition and carbon cycle.

The persistence of dissolved organic matter (DOM) plays a crucial role in the cycling and distribution of carbon and nutrients. Nonetheless, our understanding of how environmental alterations affect the persistence of sedimentary DOM remains incomplete. Excitation Emission Fluorescence Matrix-Parallel Factor Analysis (EEM-PARAFAC) was used to examine the fluorescence and compositional characteristics of hydrophilic and hydrophobic DOM (separated using XAD-8 resin) within sediments from twelve lakes and reservoirs. Fluorescence analysis indicated that DOM persistence is dependent on the proportions of the three components derived from PARAFAC. The Mantel test showed that climatic factors had the most significant impact on DOM persistence (Mantel's r = 0.46-0.54, Mantel's p = 0.001-0.007), while anthropogenic (Mantel's r = 0.24-0.32, Mantel's p = 0.03-0.05) and hydrological factors (Mantel's r = 0.03-0.22, Mantel's p = 0.06-0.40) had a somewhat lesser influence. Environmental changes resulted in a consistent decline in DOM persistence from Northeast to Southwest China, accompanied by an increase in gross primary productivity (GPP). Reduced DOM persistence due to climate, hydrological, and anthropogenic factors may lead to elevated concentrations of total phosphorus (TP), contributing to deteriorating water quality and events such as algal blooms. The decline in water quality due to reduced DOM persistence in lakes with high GPP can exacerbate the transition from carbon sinks to carbon sources. Consequently, the persistence of sedimentary DOM significantly influences nutrient and carbon cycling in lakes. Investigating DOM persistence in lakes across diverse geographic locations offers a new perspective on lake eutrophication and carbon emissions. Furthermore, it is crucial to develop targeted recommendations for lake restoration and management.

PAHs contamination in ports: Status, sources and risks.

Polycyclic aromatic hydrocarbons (PAHs) constitute important organic contaminants that have been degrading coastal ecosystems over the years. Evaluating PAH status in port ecosystems aligns with societal goals of maintaining clean habitats and sustainability. This comprehensive review systematically analyzed 123 articles, exploring the global distribution, sources, and ecological risks linked to PAH contamination in ports, focusing on water, sediment, and biota. The mean concentrations of 16 PAHs in water, sediment, and biota across worldwide ports were 175.63 ± 178.37 ng/L, 1592.65 ± 1836.5 µg/kg, and 268.47 ± 235.84 µg/kg, respectively. In line with PAH emissions and use in Asia, Asian ports had the highest PAH concentrations for water and biota, while African ports had the highest PAH concentrations for sediment. The temporal trend in PAH accumulation in sediments globally suggests stability. However, PAH concentrations in water and biota of global ports exhibit increasing trends, signaling aggravating PAH contamination within port aquatic ecosystems. Some ports exhibited elevated PAH levels, particularly in sediments with 4.5 %, 9.5 %, and 21 % of the ports categorized as very poor, poor, and moderate quality. Some PAH isomers exceeded guidelines, including the carcinogenic Benzo(a)pyrene (BaP). Coal, biomass, and petroleum combustion were major sources for PAHs. The structure of ports significantly influences the concentrations of PAHs. PAH concentrations in sediments of semi-enclosed ports were 3.5 times higher than those in open ports, while PAH concentrations in water and biota of semi-enclosed ports were lower than those in open ports. Finally, risk analyses conducted through Monte Carlo simulation indicated moderate to high risks to aquatic species, with probabilities of 74.8 % in water and 34.4 % in sediments of ports worldwide. This review underscores the imperative to delve deeper into the accumulation of PAHs and similar pollutants in ports for effective management and environmental protection.

The time between Palaeolithic hearths.

Resolving the timescale of human activity in the Palaeolithic Age is one of the most challenging problems in prehistoric archaeology. The duration and frequency of hunter-gatherer camps reflect key aspects of social life and human-environment interactions. However, the time dimension of Palaeolithic contexts is generally inaccurately reconstructed because of the limitations of dating techniques1, the impact of disturbing agents on sedimentary deposits2 and the palimpsest effect3,4. Here we report high-resolution time differences between six Middle Palaeolithic hearths from El Salt Unit X (Spain) obtained through archaeomagnetic and archaeostratigraphic analyses. The set of hearths covers at least around 200-240 years with 99% probability, having decade- and century-long intervals between the different hearths. Our results provide a quantitative estimate of the time framework for the human occupation events included in the studied sequence. This is a step forward in Palaeolithic archaeology, a discipline in which human behaviour is usually approached from a temporal scale typical of geological processes, whereas significant change may happen at the smaller scales of human generations. Here we reach a timescale close to a human lifespan.

Risk assessment of heavy metals and total petroleum hydrocarbons (TPHs) in coastal sediments of commercial and industrial areas of Hormozgan province, Iran.

The significant increase in the pollution of heavy metals and organic pollutants, their stable nature, and their high toxicity are gradually becoming a global crisis. In a recent study, a comprehensive assessment of the spatial distribution of heavy metals and total petroleum hydrocarbons (TPHs), as well as an assessment of their ecological risks in the sediments of 32 stations located in commercial and industrial areas (Mainly focusing on petrochemical and power industries, desalination plants and transit Ports) of Hormozgan province (East and West of Jask, Bandar Abbas, Qeshm, and Bandar Lengeh) was performed during 2021-2022. The sediment samples were digested with HNO3, HCl and HF solvents. The concentration of heavy metals was determined with furnace and flame systems of atomic absorption spectrometer. The concentration of heavy metals showed significant spatial changes between stations. The ecological assessment indices between the regions indicated that the stations located in Shahid Bahonar Port, Suru Beach, and Khor gorsouzuan had a higher intensity of pollution than other places and significant risks of pollution, especially in terms of Cr and Ni. The average contamination degree (CD) (14.89), modified contamination degree (MCD) (2.48), pollution load index (PLI) (2.32), and potential ecological risk index (PERI) (100.30) showed the sediments in the area of Shahid Bahonar Port, Suru beach and Khor gorsouzuan, experience significant to high levels of pollution, especially Cr and Ni. Using contamination factor (CF) and Geoaccumulation index (Igeo), Cr was considered the most dangerous metal in the studied areas. Based on the global classification of marine sediment quality for the concentrations of TPHs, the sediments of the studied stations were classified as non-polluted to low pollution. In all regions, indices of the PELq (General toxicity) and CF (Contamination factor) were much lower than 0.1 and 1 respectively, showing the absence of adverse biological effects caused by TPHs in sediments. It is necessary to consider comprehensive and impressive strategies to control and reduce pollution of heavy metals, especially in the areas of Shahid Bahonar Port, Suru Beach, and Khor gorsouzuan, so that the sources of this pollution are required to be identified and managed.

Utilization of metal and radionuclide concentrations to assess the influence of shrimp farming on the geochemical characteristics of sediments.

This article assesses the environmental impacts of aquatic biota cultivation, focusing on shrimp farming in Brazil's Northeast, as this practice has proven to be one of the main sources of economic growth in the region. For this purpose, sediment samples were collected from areas impacted and not directly impacted by shrimp farming, and concentrations of key geochemical parameters such as salinity, various elements (K, P, Cu, Mn, Pb, Zn, Al, Ca, Fe, Mg, and Na), and natural radionuclides (K-40, Ra-226 and Ra-228) were compared using statistical tools. Element concentrations were determined using ICP-OES, and naturally occurring radionuclide concentrations were obtained through gamma spectrometry. Statistical tests, such as ANOVA and/or Mann-Whitney, cluster analysis, and principal component analysis, were applied to the results. Additionally, the ERICA Tool software was employed to estimate deleterious effects on both human and non-human biota. Descriptive statistics reveal variability in sediment parameters around shrimp farming. ANOVA and Mann-Whitney tests compare concentrations of shrimp farm sediment and not directly impacted sediment, showing non-significant differences for most elements. pH and salinity, crucial for shrimp health, exhibit higher values in shrimp farm sediment. Alkali and alkaline earth metals, including K and Na, show no significant differences. Factor and cluster analyses suggest that certain elements, mainly radionuclides, are influenced by sediment variability. Hazard indices for naturally occurring radionuclides indicate negligible risk to both human and non-human biota, reinforcing the absence of adverse effects from shrimp farming activities. This study provides a comprehensive analysis of the environmental impacts of shrimp farming, emphasizing the importance of monitoring geochemical parameters for coastal environmental management.

Environmental fate of microplastics in high-altitude basins: the insights into the Yarlung Tsangpo River Basin.

Microplastics (MPs) have been found in remote high-altitude areas, but the main source and migration process remained unclear. This work explored the characteristics and potential sources of MPs in the Yarlung Tsangpo River Basin. The average abundances of MPs in water, sediment, and soil samples were 728.26 ± 100.53 items/m3, 43.16 ± 5.82 items/kg, and 61.92 ± 4.29 items/kg, respectively, with polypropylene and polyethylene as the main polymers. The conditional fragmentation model revealed that the major source of MPs lower than 4000 m was human activities, while that of higher than 4500 m was atmospheric deposition. Community analysis was further conducted to explore the migration process and key points of MPs among different compartments in the basin. It was found that Lhasa (3600 m) and Shigatse (4100 m) were vital sources of MPs inputs in the midstream and downstream, respectively. This work would provide new insights into the fate of MPs in high-altitude areas.

Particle size distribution of total suspended sediments in urban stormwater runoff: Effect of land uses, precipitation conditions, and seasonal variations.

Understanding particle size distribution (PSD) of total suspended sediments in urban runoff is essential for pollutant fate and designing effective stormwater treatment measures. However, the PSDs from different land uses under different weather conditions have yet to be sufficiently studied. This research conducted a six-year water sampling program in 15 study sites to analyze the PSD of total suspended sediments in runoff. The results revealed that the median particle size decreased in the order: paved residential, commercial, gravel lane residential, mixed land use, industrial, and roads. Fine particles less than 125 µm are the dominant particles (over 75%) of total suspended sediments in runoff in Calgary, Alberta, Canada. Roads have the largest percentage of particles finer than 32 µm (49%). Gravel lane residential areas have finer particle sizes than paved residential areas. The results of PSD were compared with previous literature to provide more comprehensive information about PSD from different land uses. The impact of rainfall event types can vary depending on land use types. A long antecedent dry period tends to result in the accumulation of fine particles on urban surfaces. High rainfall intensity and long duration can wash off more coarse particles. The PSD in spring exhibits the finest particles, while fall has the largest percentage of coarse particles. Snowmelt particles are finer for the same land use than that during rainfall events because the rainfall-runoff flows are usually larger than the snowmelt flows.

Element composition of several marine macrophytes (Crimea, Black Sea) and correlations with the element abundances in sediments and seawater.

The study of the element accumulation in marine plants against the backdrop of permanently increasing environmental pollution is of particular importance due to the participation of these plants in biogeochemical cycles. The element abundances are highly variable and depend on both the macrophyte species and environment. The purpose of this study was to analyze the elemental composition of widespread marine plants of different taxonomic affiliations collected in the same area of the Black Sea coast. The contents of 74 elements in three species of lower (red, brown, green algae) and one species of higher plants (seagrass) were analyzed using inductively coupled plasma mass spectrometry. High contents of most elements were found in the red alga Ceramium ciliatum and in rhizomes of the seagrass Zostera noltei. In C. ciliatum, high metal bioaccumulation factors were found, which are dependent also on their concentration in the environment. Compared to the higher plant, all the macroalgae accumulated increased amounts of As and I. The seagrass proved to be a good concentrator of Mo and Sb, and relatively high contents of Mn, Co, Ni, Zn, Cd and Ir were registered in its leaves. High contents of Mg, S, Ge, Se and Ta were found in the green alga Ulva rigida, and elevated levels of Al, As, Sr, Zr, Ru, Rh, Pd, Ag, Ba and Re were noted in the brown alga Gongolaria barbata. The enrichment factors for most elements in the sediments were well above 1 with respect to both the local Late Pleistocene sediments and the upper continental crust. The strength of correlations between the element contents in the plants and sediments was found to decrease with the specific surface area growth and appeared to have a lower asymptotic limit of the sediments-seawater correlation strength.