Journal of Soils and Sediments最新文献

Purpose: Riverbed sediment geochemistry provides useful information regarding metal contamination. To integrate sediment quality in river monitoring, within the WFD, the report of sediment quality to water quality managers must be expeditious. This study revisits the metal enrichment concept, applied to sediments from two mountain catchments, as a useful technique in river monitoring.

Methods: Riverbed sediment samples, collected at the end of the Dry and Wet Periods (DP, WP) were analysed for Cd, Cu, Pb, Zn, and Fe in fractions < 2 mm and < 63 µm. The metal enrichment factors (EFs) were referenced to distinct background values: average shale (AS), world rivers suspended sediments (WRSS) and Geochemical Atlas of Portugal (GAP).

Results: Cd, Cu, Pb and Zn contents are higher in the fraction < 63 µm, and at DP. The ranges of variation in fraction < 63 µm are (mg kg^-1): a) River Vilariça, Cd (5-18 DP; 0.3 WP); Cu (103-341 DP; 22-218 WP); Pb -(24-55 DP; 11-42 WP); Zn (107-241 DP; 54-103 WP); b) River Vizela, -Cd (13-44 DP; 8-41 WP); Cu (267-444 DP; 18-168 WP); Pb -(44-132 DP; 20-42 WP); Zn (141-801 DP; 36-181 WP). Variations in metal contents are influenced by lithological, geomorphological, and microclimatic features, and anthropogenic pressures. EFs are higher when referenced to AS. In the River Vizela, the EFs reveal an enrichment of Cu, Pb and Zn relative to WRSS; Cd registers an enrichment relative to GAP.

Conclusion: Local/regional background, and EFs, are relevant when assessing environmental risks in freshwater systems: low EFs, when associated to natural enrichments, originate values of concern in terms of quality guidelines; high EFs may not imply risk to the fluvial environment. Using the fraction < 63 µm in river monitoring is considered adequate. In dynamic mountain streams, recent sediments and associated contaminants are retained, providing information on possible pollution sources. Identifying metals contamination (or natural enrichment) can help decision-makers to provide solutions for pollution sources.

Supplementary information: The online version contains supplementary material available at 10.1007/s11368-025-03963-6.

Purpose: Insight into the distribution and sedimentation patterns of organic and inorganic carbon (OC and IC) in urban lake sediments is essential for understanding their role in the carbon (C) cycling of inland waters and supporting effective ecosystem management.

Methods: This study investigated the spatial variability of sediment OC and IC accumulation in a mesotrophic human-made urban lake (Lake Berendonck; 45 ha) by combining high-resolution hydroacoustic sub-bottom profiling surveys and sediment coring.

Results: The results revealed strong spatial variations in sediment C accumulation rates. Deep central and southeastern areas of the lake exhibited relatively high C deposition, even though deep areas with low C content were also found. Lake Berendonck had a mean ± standard deviation sediment accumulation rate of 0.7 ± 0.5 cm year^- 1, with areal OC and IC accumulation rates ranging between 24 and 557 and 3-37 g m^- 2 year^- 1, respectively. Lake Berendonck's mean sediment OC accumulation rate (155 g m^- 2 year^- 1) was approximately four times higher than the mean OC accumulation rate of global lakes (37 g m^- 2 year^- 1), while Lake Berendonck's mean IC accumulation rate (12 g m^- 2 year^- 1) falls in the mid-range for global lakes and seas.

Conclusions: Our findings indicate that C accumulation is highly variable in space and that spatially integrated data are needed to estimate C stocks and unravel within-lake C processes reliably. Furthermore, this study highlights that the OC accumulation in Lake Berendonck ranks among the highest rates observed in global lakes with similar surface areas (0.4-0.5 km²). This underscores the global importance of small urban water bodies in C cycling, particularly as key C storage systems.

Supplementary information: The online version contains supplementary material available at 10.1007/s11368-025-04029-3.

Purpose: Large soil organic carbon (SOC) reserves and a high soil capacity for SOC storage within an ecosystem contribute to mitigating the release of carbon into the atmosphere. Developing new spatially-explicit SOC estimation methods at local and micro-watershed scales is essential for gaining landscape understanding of SOC variability.

Methods: This study provides new insights into the spatial variability of SOC in the Andean páramo soils. A range of variables from different sources (i.e., geophysical, meteorological, topographic, and spectral) were analyzed to identify driving variables to explain the SOC dynamic in the Andean páramo highlands of the Real range in the central region of Ecuador. This information was used to calibrate a SOC prediction model using Classification and Regression Trees (CART) and soil data samples from the 0-30 cm soil horizon.

Results: Eight key variables linking with the SOC storage were used to calibrate the model for SOC estimation with an accuracy of 67% with an RMSE value of 2.17%. Results reveal that sand content emerged as the most significant variable, while taxonomic suborder and protected area variables provided crucial supplementary information. This study improves the ability to detect changes in SOC, particularly in smaller areas where traditional predictors, often more suitable for regional or national assessments, may exhibit insufficient explanatory power.

Conclusion: The Andean páramo highlands of the Real range show high capacity for storing SOC, with values ranging from 3.5% to 19%. This variability highlights the ecosystem's importance as a globally relevant carbon reservoir.

Purpose

This study aims to evaluate the impact of peanut straw mulching on the N change and the functional genes in Camellia oleifera intercropping systems.

Methods

A field experiment with different types of straw mulch treatments (conventional tillage, whole, and crushed) and timing was (50 d and 150 d) established between 2018–2022; the soil N fractions, N transformation rates, the abundance and dominant species compositions of ammonia-oxidizing archaea (AOA), nirK, and nirS-harboring genes were investigated.

Results

The whole peanut straw mulching of 150 d significantly improved (P < 0.05) the content of soil microbial biomass N (MBN), ammonia N (NH₄⁺), and nitrate N (NO₃^-). The soil nitrification and ammonification rates increased by 96.8% and 132% in the 150 d of peanut crushed and whole straw mulching, respectively. Notably, the peanut straw mulching of 50 d mainly affects the diversity and relative abundance of AOA while the soil nirK and nirS-harboring genes were affected by 150 d crushed and whole peanut straw mulching, respectively. Redundancy analysis showed that crushed and whole peanut straw mulching affects nitrate reductase as the primary factor in regulating the soil N cycle via functional genes and soil variables.

Conclusions

Long-term whole peanut straw or whole and crushed mixed straw mulching could hence be recommended to dryland farming communities to increase the soil N cycle and crop productivity in the C.oleifera-peanut intercropping system.

Purpose

Chemical immobilization using hydroxyapatite (HAP) is a cost effective and environmentally sound strategy for remediating lead-contaminated soils, such as shooting range soils. Understanding the combined impact of soil chemical and physical properties on enhancing the formation of pyromorphite, a lead-insoluble phase, is crucial for mitigating environmental risks associate with contaminated soil. This study aimed to elucidate the relationship between percolation velocity and lead leaching as well as pyromorphite transformation to optimize pyromorphite formation in water-unsaturated soils.

Methods

Two up-flow suction percolation tests were performed: one varying percolation velocity with soil porosity achieved by incorporating clay minerals, and the other varying percolation velocity while keeping soil porosity constant.

Results

Application of HAP substantially suppressed lead leaching in both percolation tests. Enhanced pyromorphite formation was observed with higher percolation velocities relative to soil porosity. Pyromorphite formation was more pronounced at lower percolation velocities compared to higher velocities at equivalent soil porosity level. The percentages of lead formed as pyromorphite in HAP-treated soil were higher than those of lead leached in non-HAP-treated soil among the lower percolation velocities.

Conclusions

This study provides experimental evidence indicating pyromorphite formation is favored in soils with lower percolation velocities and higher soil porosities. Therefore, considering both soil chemical and physical properties is essential for understanding immobilization mechanisms in contaminated soils.

Purpose

Sediments from marine areas contain salt, limiting beneficial use possibilities. This study investigates the impact of rinsing with fresh water on ion concentration and organic matter (OM) content in marine sediments, and how salinity hinders water release under induction.

Methods

In a lab simulation, marine sediment was mixed with fresh water (1:6 volume ratio) for 5 min at 285 rpm using a HOBART planet N-50 Mixer. An adapted Thermogravimetric Analysis (TGA) procedure determined the OM content and the temperature at which all water was released.

Results

Mixing sediment with fresh water reduced ion concentrations. Monovalent ions like sodium and chloride were released immediately, while higher valence ions like sulfate and phosphate were released gradually. Rinsing with fresh water also reduced OM content. A second mix with the salty supernatant water did not further reduce salinity or OM.

Conclusion

Determining OM content in salty sediments requires continuous mass loss monitoring to identify the temperature at which all water is removed. For agricultural reuse, maintaining nutrient levels and OM while reducing salt content to prevent groundwater salinization is crucial. Supernatant water should be removed promptly after rinsing to halt nutrient removal. The results of this study contribute to beneficial reuse of dredged sediment.

Purpose

Learning science in early years can cultivate children’s curiosity and enjoyment in exploring the world around them, laying the foundation for the progression of science learning and ultimately increasing science literacy. Here, we present an example of a tailored preschool scientific activity designed to enhance literacy about sediments and illustrate their importance to both humans and nature.

Methods

The activity centres around a captivating story detailing the journey of a sand grain from the mountains to the sea. This storytelling experience is enriched with hands-on observation of various sand grains, informative cards on key topics, and culminates in a creative colouring activity.

Results

To date, the activity has been repeated five times, engaging 110 children (from 2 to 10 years). It has yielded positive outcomes with both preschool and primary school students, as they were actively engaged in the story and delighted in handling and observing the magnified sand grains.

Conclusions

The activity was successfully implemented for preschool and primary school students, fostering engagement with the story and the sand samples. However, while the immediate engagement was evident, the impact on sediment literacy remains to be measured. Future structured evaluations are needed to assess the long-term effectiveness of such initiatives in enhancing sediment literacy among young learners.

Purpose

Incorporating rice straw into upland has been adopted as a strategy to increase crop productivity and decrease poisoning to rice from reducing substances accumulation as well as mitigate methane emission from paddy fields in South China. However, the mechanism underlying long-term ex situ incorporation of rice straw in upland on soil organic carbon (SOC) and crop yields through microbial metabolism remains unclear.

Materials and methods

Hence, a field experiment was established to investigate the response mechanism of SOC and crop yields underlying microbe-mediated carbon dynamics with nutrient stoichiometry by ex situ incorporation of rice straw in upland.

Results and discussion

The results showed that the treatment of cropping with chemical fertilizers plus rice straw (SCF) had the highest SOC accumulation rate (0.14 ± 0.03 g C kg⁻¹ yr⁻¹) during the 22-year experimental period. The mean yields of rapeseed and sweet potato were increased by 5.0% and 4.7% in the SCF treatment, correspondingly, compared with the treatment of cropping with chemical fertilizers (CF). Additionally, based on ecoenzymatic stoichiometry, soil microorganisms were found to be co-limited by carbon and phosphorus, which was aggravated by the decrease of soil available nutrients. The SCF treatment exhibited a higher soil microbiomass, resulting in an increased secretion of ecoenzymatic activities to mediate stoichiometric imbalance and mitigate nutrient competition between plant and microbial nutrient limitations. The findings revealed a significant association between stoichiometric imbalance and both SOC and crop yields, respectively.

Conclusions

Therefore, our study indicated that long-term ex situ incorporation of rice straw in upland could be adopted as an effective agricultural management strategy to improve SOC and crop yields.

Purpose

Phosphorus (P) sorption processes in soils can influence P plant-availability and influence ‘build-up’ and ‘draw-down’ P cycles. Current fertiliser recommendations do not take these processes into account. This study aimed to integrate soil P sorption behaviour and P agronomic-indices to strengthen P management recommendations.

Methods

Mineral soil covering 35,716-km² of Ireland was characterised by P status (Morgan’s P and Mehlich-3 P), and Langmuir sorption parameters of P sorption maximum capacity (Smax, mg·kg⁻¹) and binding energy (k, L·mg⁻¹).

Results

Segmented regression between Smax and M3-Al (R² = 0.49) identified a significant change-point at Smax = 450.03 mg·kg⁻¹, at which soils can be placed into ‘low’ (SL_M3-Al) and ‘high’ (SH_M3-Al) P sorbing classes. Sorption parameters in SL_M3-Al did not change with soil P status; however, in high P sorbing soils, sorption parameters significantly correlated with P status. High sorbing soils that are P-deficient (Index 1 and 2) will ‘fix’ P and take longer to build-up plant available P to a value for agronomic production (Index 3). Low P sorbing soils at high P status (Index 4) will decline to Index 3 at faster rates than high P sorbing soils. These soils (SL_M3-Al) are at higher risk of soluble P losses to water because of lower binding energies.

Conclusions

Efficient P fertiliser use can be more effective if soils are delineated into ‘low’ and ‘high’ sorbing soils coupled with soil P status. By integrating P sorption capacities with agronomic soil P indices, fertiliser advice and water quality measures can be targeted and more effective.

Purpose

The study aims to assess the ecological risks posed by metal contamination in Montenegrin marine sediments, focusing on both Boka Kotorska Bay and the coastal part of the open sea. By analyzing metal concentrations and identifying potential pollution hotspots and sources, the research seeks to contribute to a better understanding of the escalating threats to coastal regions and their ecological implications due to anthropogenic activities.

Methods

Total concentrations of Fe, Mn, Cr, Ni, Zn, Cu, Pb, As, Hg, and Cd were determined in surface sediment samples collected from 10 sites along the Montenegrin coast, targeting areas influenced with different sources and levels of anthropogenic pollution. Statistical analysis was performed, and various pollution indices (contamination factor (C_f), geo-accumulation index (Igeo), potential ecological risk factor (({E}_{r}^{i})), pollution load index (PLI), risk index (RI), mean ERM quotient (MERMQ), and toxic risk index (TRI)) were calculated to assess contamination status, severity of pollution, and potential ecological risks.

Results

The results showed varying levels of metals, with elevated concentrations of Fe, Mn, Ni, and Cr at location S10 (Ada Bojana), and higher Cu, Pb, Hg, and Zn levels at S5 (Bijela). C_f and Igeo values indicated mainly moderate to considerable pollution, with Pb concentrations of particular concern. Ecological risks were posed by Hg and, in some cases, Cd, while Ni concentrations presented the highest toxic risk to marine organisms according to TRI_i values. Overall, pollution was present in the entire area, with mainly moderate ecological risk according to RI values, but considerable to very high toxic risks highlighted by MERMQ and TRI values at various locations.

Conclusion

This study revealed overall pollution presence in surface sediments along the Montenegrin coast, predominantly associated with anthropogenic sources, thereby posing potential ecological risks, particularly in Boka Kotorska Bay and at S10 (Ada Bojana). The obtained results highlighted the need for continued monitoring and management strategies to mitigate environmental impacts.