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Land degradation resulting from soil erosion is a global concern, with the greatest risk in developing countries where food and land resources can be limited. The use of fallout radionuclides (FRNs) is a proven method for determining short and medium-term rates of soil erosion, to help improve our understanding of soil erosion processes. There has been limited use of these methods in tropical Africa due to the analytical challenges associated with 137Cs, where inventories are an order of magnitude lower than in the Europe. This research aimed to demonstrate the usability of 239+240Pu as a soil erosion tracer in western Kenya compared to conventional isotopes 210Pbex and 137Cs through the determination of FRN depth profiles at reference sites. Across six reference sites 239+240Pu showed the greatest potential, with the lowest coefficient of variation and the greatest peak-to-detection limit ratio of 640 compared to 5 and 1 for 210Pbex and 137Cs respectively. Additionally, 239+240Pu was the only radionuclide to meet the ‘allowable error’ threshold, demonstrating applicability to large scale studies in Western Kenya where the selection of suitable reference sites presents a significant challenge. The depth profile of 239+240Pu followed a polynomial function, with the maximum areal activities found between depths 3 and 12 cm, where thereafter areal activities decreased exponentially. As a result, 239+240Pu is presented as a robust tracer to evaluate soil erosion patterns and amounts in western Kenya, providing a powerful tool to inform and validate mitigation strategies with improved understanding of land degradation.

The analysis of plutonium (Pu) in soil samples can inform the understanding of soil erosion processes globally. However, there are specific challenges associated for analysis in tropical soils and so an optimal analytical methodology ensuring best sensitivity is critical. This method aimed to demonstrate the feasibility of sample preparation and analysis of Pu isotopes in African soils, considering the environmental and cost implications applicable to low-resource laboratories. The separation procedure builds upon previous work using TEVA columns, further demonstrating their usefulness for the reduction of uranium (U) interference in ICP-MS analysis with enhanced selectivity for Pu. Here several steps were optimised to enhance Pu recovery, reducing method blank concentration, and improving the separation efficiency through the determination of the elution profiles of U and Pu. The elimination of the complexing agent in the eluent, increased the spike recovery by improving matrix tolerance of the plasma, and simplified the separation procedure, improving throughput by 20%. The subsequent method was validated through the analysis of Certified Reference Material IAEA-384, where high accuracy and improved precision of measurement were demonstrated (measured value 114 ± 12 versus certified value 108 ± 13 Bq kg−1). Optimisation of the column separation, along with the analysis of the samples using O2 gas in ICP-MS/MS mode to mass shift Pu isotopes away from interfering molecular U ions provided a simple, robust, and cost-effective method with low achievable method detection limits of 0.18 pg kg−1 239+240Pu, applicable to the detection of ultra-trace fallout Pu in African soils.

The measurement of isotopic abundances and ratio variations of plutonium can provide important information about the sources and behaviours of radiogenic isotopes in the environment. The detection of ultra-trace isotopes of plutonium is increasing interest in the scientific literature for the determination of soil erosion rates due to their long retention times in the environment. The characteristics of plutonium within the environment make it an ideal tracer for the determination of soil redistribution rates and its robustness presents the opportunity to replace more commonly used radioisotopes such as 137Cesium and 210Lead. However, ultra-trace analysis of plutonium (fg g−1) presents analytical challenges which must be overcome in a variety of soil types. Inductively Coupled Plasma Mass Spectrometry has proven valuable for detection of plutonium in a range of environmental samples. However, severe polyatomic interferences from uranium isotopes significantly limits its application. Due to the improvements in detection sensitivity and reaction cell technology, inductively coupled plasma tandem mass spectrometry, which is also commonly referred to as triple quadrupole inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), has emerged as an exceptional tool for ultra-trace elemental analysis of plutonium isotopes in environmental samples overcoming the limitations of standard quadrupole ICP-MS such as limited sensitivity and cost of analysis. In this review, common methods reported in the literature for the separation and subsequent detection of plutonium isotopes are compared to recent advances in analysis using ICP-MS/MS technology.

Soil erosion accelerated by poor agricultural practices, land degradation, deprived infrastructure development and other anthropogenic activities has important implications for nutrient cycling, land and lake productivity, loss of livelihoods and ecosystem services, as well as socioeconomic disruption. Enhanced knowledge of dynamic factors influencing soil erosion is critical for policymakers engaged in land use decision-making. This study presents the first spatio-temporal assessment of soil erosion risk modelling in the Winam Gulf, Kenya using the Revised Universal Soil Loss Equation (RUSLE) within a geospatial framework at a monthly resolution between January 2017 and June 2020. Dynamic rainfall erosivity and land cover management factors were derived from existing datasets to determine their effect on average monthly soil loss by water erosion. By assessing soil erosion rates with enhanced temporal resolution, it is possible to provide greater knowledge regarding months that are particularly susceptible to soil erosion and can better inform future strategies for targeted mitigation measures. Whilst the pseudo monthly average soil loss was calculated (0.80 t ha−1 month−1), the application of this value would lead to misrepresentation of monthly soil loss throughout the year. Our results indicate that the highest erosion rates occur between February and April (average 0.95 t ha−1 month−1). In contrast, between May and August, there is a significantly reduced risk (average 0.72 t ha−1 month−1) due to the low rainfall erosivity and increased vegetation cover as a result of the long rainy season. The mean annual gross soil loss by water erosion in the Winam Gulf catchment amounts to 10.71 Mt year−1, with a mean soil loss rate of 9.63 t ha−1 year−1. These findings highlight the need to consider dynamic factors within the RUSLE model and can prove vital for identifying areas of high erosion risk for future targeted investigation and conservation action.

Subsistence farmers in Africa are often dependent on food grown within a limited area, and therefore, their health can often be associated with geochemical factors that influence the soil-tocrop transfer of micronutrients (MN) essential for health. Loss of essential MN because of soil erosion can affect both crop yields and the protection of crops against disease, which could dramatically increase the likelihood of food shortages worldwide. In addition to the effects on land, the associated downstream transport of sediments to water bodies associated with soil erosion can impact water security. A large proportion of the degradation caused by soil erosion processes is a direct result of poor land management practises as well as vegetation clearance, and so there is a need for reliable quantitative data detailing rates of soil erosion and sedimentation. This data can then help to reinforce sustainable soil conservation measures in areas where resources to manage soils sustainably can be limited. This research aims to investigate the potential of using plutonium as an alternative tracer of soil erosion in challenging environments such as tropical Africa. This will allow for further research into the extent of soil erosion across East Africa and inform future mitigation efforts to reduce further erosion in the future.

Soil erosion accelerated by poor agricultural practices, land degradation, deprived infrastructure development and other anthropogenic activities has important implications for nutrient cycling, land and lake productivity, loss of livelihoods and ecosystem services, as well as socioeconomic disruption. Enhanced knowledge of dynamic factors influencing soil erosion is critical for policymakers engaged in land use decision-making. This study presents the first spatio-temporal assessment of soil erosion risk modelling in the Winam Gulf, Kenya using the Revised Universal Soil Loss Equation (RUSLE) within a geospatial framework at a monthly resolution between January 2017 and June 2020. Dynamic rainfall erosivity and land cover management factors were derived from existing datasets to determine their effect on average monthly soil loss by water erosion. By assessing soil erosion rates with enhanced temporal resolution, it is possible to provide greater knowledge regarding months that are particularly susceptible to soil erosion and can better inform future strategies for targeted mitigation measures. Whilst the pseudo monthly average soil loss was calculated (0.80 t ha−1 month−1), the application of this value would lead to misrepresentation of monthly soil loss throughout the year. Our results indicate that the highest erosion rates occur between February and April (average 0.95 t ha−1 month−1). In contrast, between May and August, there is a significantly reduced risk (average 0.72 t ha−1 month−1) due to the low rainfall erosivity and increased vegetation cover as a result of the long rainy season. The mean annual gross soil loss by water erosion in the Winam Gulf catchment amounts to 10.71 Mt year−1, with a mean soil loss rate of 9.63 t ha−1 year−1. These findings highlight the need to consider dynamic factors within the RUSLE model and can prove vital for identifying areas of high erosion risk for future targeted investigation and conservation action.

The northwest region of the Iberian Peninsula is home to a unique ecosystem of bogs, which are particularly sensitive to projected climate change. In this context, the rate of carbon (C) accumulation in Chao de Veiga Mol, an intact raised bog, was analysed. Changes in the accumulation rate over the past 10 millennia were determined in a peat core of 847 cm in depth, with a high mean rate of peat growth (11 yr cm−1, 0.09 cm yr−1). An age-depth model was generated from 22 14C dates and fallout radionuclides. Chronological, stratigraphical and physico-chemical data confirmed the existence of a single cycle of peat formation throughout the Holocene and the formation of ombrotrophic peat 9500 years ago. The total mean C content was 50.2%, and over 10 millennia 583 kg C m−2 accumulated at a mean rate of 35.3 g C m−2 yr−1, with a long-term (apparent) rate of carbon accumulation in the catotelm of 59.9 g C m−2 yr−1. These values are much higher than reported for other Iberian peatlands and are amongst the highest documented for peatlands in the northern hemisphere. The dynamics of C accumulation and other measured parameters reveals important variations throughout the Holocene. They could be associated with the main climatic events described in the northern hemisphere and are highly consistent with models established for northern latitudes. The Chao de Veiga Mol raised bog is unique and of great potential value for carrying out high resolution palaeoenvironmental studies, especially in relation to regional and local modulations in southern Europe.

[EN] The northwest region of the Iberian Peninsula is home to a unique ecosystem of bogs, which are particularly sensitive to projected climate change. In this context, the rate of carbon (C) accumulation in Chao de Veiga Mol, an intact raised bog, was analysed. Changes in the accumulation rate over the past 10 millennia were determined in a peat core of 847 cm in depth, with a high mean rate of peat growth (11 yr cm1, 0.09 cm yr1). An age-depth model was generated from 22 14C dates and fallout radionuclides. Chronological, stratigraphical and physico-chemical data confirmed the existence of a single cycle of peat formation throughout the Holocene and the formation of ombrotrophic peat 9500 years ago. The total mean C content was 50.2%, and over 10 millennia 583 kg C m2 accumulated at a mean rate of 35.3 g C m2 yr1, with a long-term (apparent) rate of carbon accumulation in the catotelm of 59.9 g C m2 yr1. These values are much higher than reported for other Iberian peatlands and are amongst the highest documented for peatlands in the northern hemisphere. The dynamics of C accumulation and other measured parameters reveals important variations throughout the Holocene. They could be associated with the main climatic events described in the northern hemisphere and are highly consistent with models established for northern latitudes. The Chao de Veiga Mol raised bog is unique and of great potential value for carrying out high resolution palaeoenvironmental studies, especially in relation to regional and local modulations in southern Europe

The loss of fertile topsoil is one of the principal soil degradation problems in mountain agroecosystems worldwide. Soil erosion rates reach their maximum during exceptional storm events that remove soil particles, especially from unprotected topsoil. In Mediterranean mountainous environments, several centuries of non-irrigated agriculture and the subsequent removal of natural vegetation for developing agriculture has increased the surface area prone to erosion. In addition, the irregularity in exceptional precipitation events results in a great loss of fertile soil, the subsequent siltation of reservoirs and a decrease in water quality. To analyse the soil response to exceptional events, 161 source samples were collected in a 23 km2 catchment that was mostly cultivated at the beginning of the last century. Source samples were distributed over the five main land use/land covers such as agricultural land, pine afforestation, open forest, bare soil and channel bank areas. Furthermore, 20 channel bed sediment samples were collected along the main streams before and after the exceptional storm event to document changes in the sediments. In addition, floodplain sediments were collected to provide a close replication of sediments deposited during regular storm events. Source apportionments were calculated using the FingerPro unmixing model in the pre-event, regular events and post-event scenarios. The unmixing outputs displayed a large variation of source apportionments from the upper part to the lower part of the catchment and from pre- to post-event sediments. After the event, a decrease of >70% of the clay fraction and its associated elements such as Fe, Al, K, Ba, Sr, Rb, Pb, Zn, V, 137Cs, 40K, 232Th and SOC along with a rise in contents of elements associated with the coarse fraction (Si, Nb, Zr, Ti, P and 226Ra) was recorded in the channel bed sediments. At the catchment outlet, the pre-event sediment showed substantial contributions from bare soil (29%) and from ag

In the Mediterranean region, floods are expected to increase as a result of climate change and knowledge of soil erosion hot spots during exceptional rainfalls is required to support mitigation measures. This study quantifies the main sediment sources during an exceptional rainfall event in 2012 (235 mm) at the outlet of two catchments located in NE Spain. To this purpose, suspended sediments were collected during the flood event, complemented with entrapped sediments in mat taken one year after the event. We used fingerprinting methodology and applied the FingerPro unmixing model to estimate the contribution from main sources. The selected tracers clearly distinguished agricultural, rangeland, subsoil and channel banks as the four potential sources in both catchments. In the Vandunchil catchment, the 8 time-integrated suspended sediment samples revealed changes in source contribution during the 2-h sampling sequence. There were relatively high contributions from rangeland, agriculture and subsoil at the beginning of the sampling, representing 30, 40 and 35% of the total source contributions, respectively. Our records captured the delivery of pulses of eroded surface soil transported by runoff with direct connectivity to the stream. The sequence was followed by a sharp increase in channel bank contribution (up to 90%) in comparison to the other sources, reflecting streambank erosion and landslide occurrence, which manifested during the flood. In contrast, in the La Reina catchment, agricultural soils contributed the most (65%) and, together with subsoils (32%), were the main sources. These results reflect the effect of the higher connectivity and slope gradient of these cultivated fields of the La Reina catchment in comparison with those of the Vandunchil catchment. We discuss the possibility of using different properties, such as radionuclides, geochemistry and magnetic measurements, as tracers to distinguish between potential sources during an exceptional event in

Implementation of socially acceptable and environmentally desirable solutions to soil erosion challenges is often limited by (1)fundamental gaps between the evidence bases of different disciplines and (2) an implementation gap between science-based recommendations, policy makers and practitioners. We present an integrated, interdisciplinary approach to support co-design of land management policy tailored to the needs of specific communities and places in degraded pastoral land in the East African Rift System. In a northern Tanzanian case study site, hydrological and sedimentary evidence shows that, over the past two decades, severe drought and increased livestock have reduced grass cover, leading to surface crusting, loss of soil aggregate stability, and lower infiltration capacity. Infiltration excess overland flow has driven (a)sheet wash erosion, (b)incision along convergence pathways and livestock tracks, and (c) gully development, leading to increased hydrological connectivity. Stakeholder interviews in associated sedenterising Maasai communities identified significant barriers to adoption of soil conservation measures, despite local awareness of problems. Barriers were rooted in specific pathways of vulnerability, such as a strong cattle-based cultural identity, weak governance structures, and a lack of resources and motivation for community action to protect shared land. At the same time, opportunities for overcoming such barriers exist, through openness to change and appetite for education and participatory decision-making. Guided by specialist knowledge from natural and social sciences, we used a participatory approach that enabled practitioners to start co-designing potential solutions, increasing their sense of efficacy and willingness to change practice. This approach, tested in East Africa, provides a valuable conceptual model around which other soil erosion challenges in the Global South might be addressed.

Increasing complexity in human-environment interactions at multiple watershed scales presents major challenges to sediment source apportionment data acquisition and analysis. Herein, we present a step-change in the application of Bayesian mixing models: Deconvolutional-MixSIAR (D-MIXSIAR) to underpin sustainable management of soil and sediment. This new mixing model approach allows users to directly account for the ‘structural hierarchy’ of a river basin in terms of sub-watershed distribution. It works by deconvoluting apportionment data derived for multiple nodes along the stream-river network where sources are stratified by sub-watershed. Source and mixture samples were collected from two watersheds that represented (i) a longitudinal mixed agricultural watershed in the south west of England which had a distinct upper and lower zone related to topography and (ii) a distributed mixed agricultural and forested watershed in the mid-hills of Nepal with two distinct sub-watersheds. In the former, geochemical fingerprints were based upon weathering profiles and anthropogenic soil amendments. In the latter compound-specific stable isotope markers based on soil vegetation cover were applied. Mixing model posterior distributions of proportional sediment source contributions differed when sources were pooled across the watersheds (pooled-MixSIAR) compared to those where source terms were stratified by sub-watershed and the outputs deconvoluted (D-MixSIAR). In the first example, the stratified source data and the deconvolutional approach provided greater distinction between pasture and cultivated topsoil source signatures resulting in a different posterior distribution to non-deconvolutional model (conventional approaches over-estimated the contribution of cultivated land to downstream sediment by 2 to 5 times). In the second example, the deconvolutional model elucidated a large input of sediment delivered from a small tributary resulting in differences in the reported contr

In this contribution, key components of the model are evaluated in the context of common experimental designs for sediment fingerprinting studies namely simple, nested and distributed catchment sampling programmes.

The elevated supply and transfer of sediment in river systems can impact on water resource infrastructure, water quality and ecosystem health around the world. Moreover, the loss of reservoir capacity due to siltation is of particular concern in regions that experience water scarcity, such as the Mediterranean. Therefore, quantifying the sediment production from contributing catchments to reservoirs is of major interest to support the development of management plans for maintaining reservoir sustainability. Within this context, sediment production from a catchment in the central Spanish Pyrenees was investigated by combining the outputs of the Soil and Water Assessment Tool (SWAT) model with sediment source fingerprinting. The study examined the large alpine-prealpine catchment of the Barasona reservoir, which is an agroforest catchment supplying sediment to the reservoir at an annual rate of around 3.5 t ha− 1. For the period 2003–2005 the simulated specific sediment yields for the catchment by SWAT model are mostly below 2 t ha− 1 year− 1 with maximum values reaching 250 t ha− 1 year− 1. Simulated sediment production is dependent on (i) land use/cover, (ii) precipitation amounts and (iii) slope gradients. The highest sediment yield was simulated for the badlands, in the wettest year and for the greatest slope gradients. The predicted catchment source contributions obtained for the reservoir sediments were low (< 7%) for forest and scrubland sources, greater for agricultural sources and exceeded 50% for subsoil sources. Results from both procedures indicate that badlands are the main sediment source while agricultural land is of secondary importance. This combination of procedures allowed catchment sediment production and source contributions to be linked to reservoir infilling. It also demonstrates the benefits of combined modelling and sediment fingerprinting approaches in complex catchments where siltation threatens water and energy security.

In this contribution, key components of the model are evaluated in the context of common experimental designs for sediment fingerprinting studies namely simple, nested and distributed catchment sampling programmes. Illustrative examples using geochemical and compound specific stable isotope datasets are presented and used to discuss best practice with specific attention to (1) the tracer selection process, (2) incorporation of fixed effects relating to sample timeframe and sediment type in the modelling process, (3) deriving and using informative priors in sediment fingerprinting context and (4) transparency of the process and replication of model results by other users.

Fine-grained sediment is perhaps the most widespread and pervasive contaminant in aquatic systems reflecting its role in influencing the quality of the water (e.g., turbidity, vector of chemicals and other pollutants) and its detrimental effect on infrastructure (e.g., dams, turbines) and aquatic habitats (e.g., salmonid spawning grounds) through sedimentation. Determining the sources of fine-grained sediment thus represents an important requirement for watershed and coastal management, as well as for understanding the evolution of landscapes and ocean basins. Sediment source fingerprinting utilizes the diagnostic physical, chemical and biological properties (i.e., tracers) of source materials to enable samples of collected sediment to be apportioned to these sources. This review examines the development of the technique within the earth and ocean sciences, focusing mainly on agricultural landscapes. However, the development of new tracers, such as compound-specific stable isotopes, has allowed the technique to be applied in a growing number of environmental settings including forested (including wildfire-impacted forests), urban and estuarine/coastal settings. This review also describes other applications of the fingerprinting approach such as geoarchaeological (e.g., archaeological site formation), forensic (e.g., identifying the sources of soil/sediment particles in criminal investigations) and human health (e.g., identifying the sources of airborne particulate matter, PM2.5) applications. Identifying commonalities in methods and approaches between environments and disciplines should foster collaboration and the exchange of ideas. Furthermore, refinement of the sediment source fingerprinting technique requires that several methodological issues be addressed. These methodological issues range from the initial sampling design to the interpretation of the final apportionment results. This review also identifies and assesses these methodological concerns.

Information on sediment sources in river catchments is required for effective sediment control strategies, to understand sediment, nutrient and pollutant transport, and for developing soil erosion management plans. Sediment fingerprinting procedures are employed to quantify sediment source contributions and have become a widely used tool. As fingerprinting procedures are naturally variable and locally dependant, there are different applications of the procedure. Here, the auto-evaluation of different fingerprinting procedures using virtual sample mixtures is proposed to support the selection of the fingerprinting procedure with the best capacity for source discrimination and apportionment. Surface samples from four land uses from a Central Spanish Pyrenean catchment were used i) as sources to generate the virtual sample mixtures and ii) to characterise the sources for the fingerprinting procedures. The auto-evaluation approach involved comparing fingerprinting procedures based on four optimum composite fingerprints selected by three statistical tests, three source characterisations (mean, median and corrected mean) and two types of objective functions for the mixing model. A total of 24 fingerprinting procedures were assessed by this new approach which were solved by Monte Carlo simulations and compared using the root mean squared error (RMSE) between known and assessed source ascriptions for the virtual sample mixtures. It was found that the source ascriptions with the highest accuracy were achieved using the corrected mean source characterisations for the composite fingerprints selected by the Kruskal Wallis H-test and principal components analysis. Based on the RMSE results, high goodness of fit (GOF) values were not always indicative of accurate source apportionment results, and care should be taken when using GOF to assess mixing model performance. The proposed approach to test different fingerprinting procedures using virtual sample mixtures provides an enhanc

In the present study, the results from a fingerprinting procedure and the SWAT model were compared and combined to improve the knowledge of land use sediment source contributions to the reservoir. Samples from the study catchment were used to define soil parameters for the model and for fingerprinting the land use sources. The fingerprinting approach provided information about relative contributions from land use sources to the superficial sediment samples taken from the reservoir infill. The calibration and validation of the model provided valuable information, for example on the timescale of sediment production from the different land uses within the catchment. Linking results from both techniques enabled us to achieve a more holistic view of the erosion processes taking place in the Barasona river catchment.

This study aimed to quantify the flux of radiocesium in the Abukuma Basin (5,172 km(2)), the largest river system affected by fallout from the Fukushima Daiichi Nuclear Power Plant (FDNPP) event. In the period from 10 August 2011 to 11 May 2012 an estimated 84 to 92% of the total radiocesium transported in the basin's fluvial system was carried in particulate form. During this monitoring period Typhoon Roke (September 2011) was observed to induce a significant and temporally punctuated redistribution of radiocesium. The storm-mobilised radiocesium was an estimated 6.18 Terabecquerels corresponding to 61.4% of the total load delivered to the coastal zone during the observation period. The total flux of radiocesium into the Pacific Ocean estimated at the outlet station (basin area 5,172 km(2)) was 5.34 TBq for (137)Cs, and 4.74 TBq for (134)Cs, corresponding to 1.13% of the total estimated radiocesium fallout over the basin catchment (890 TBq). This was equivalent to the estimated amount of direct leakage from FDNPP to the ocean during June 2011 to September 2012 of 17 TBq and the Level 3 Scale Leakage on 21 August 2013 (24 TBq).

Se determinó la concentración de Hg e hidrocarburos aromáticos policíclicos (HAPs) en una turbera ombrotrófica de la Serra do Xistral (N Galcicia) y su distribución durante los últimos 300 años. Los resultados muestran que ambos pueden estar comportándose ambientalmente de forma similar, movilizándose por la atmósfera a larga distancia hacia latitudes más septentrionales. Hg y los HAPs de alto peso molecular parecen compartir las mismas fuentes de emisión incrementándose sustancialmente su acumulación en los últimos 100 años con una caída apreciable desde hace 10 años.

The sediment fingerprinting technique can provide information to help identify and quantify the source of mobilised sediments in agroforestry catchments. Discriminating the potential contribution from sediment sources is necessary for the understanding of soil redistribution processes and, to support soil and water resources conservation and catchment management strategies. Sediment fingerprinting experiments have been used to demonstrate the sensitivity of numerical mixing model outputs to different particle size distributions in source materials and experimental sediment mixtures. Relationships between tracer properties and particle size are not always consistent between fingerprint elements due to different controls (e.g. mineralogy versus adsorption). Results suggested that particle size correction procedures require careful scrutiny in the context of variable source characteristics and that fractionation of source and receptor materials to compare like-with-like across the size range might improve mixing model output. Accordingly, the influence of source material particle size distribution on mixing model output and uncertainty need to be tackled. To explore this factor in more detail, experimental sediment mixtures were prepared by combining different proportions of the <63 µm fraction of experimental source soils with significantly different geochemistry. Subsequently, both experimental sources and sediment mixtures were dry sieved at <40 µm and <20 µm. In an attempt to understand if particle-size correction factors may be appropriate under certain conditions, the specific relationships between individual major and minor element geochemical constituents and particle size fractions were explored. The results from mixing model comparisons of like-with-like (at <63, <40 and <20 µm) for both source materials and the different sediment mixtures are discussed in the context of the variable impact of fluvial sorting on end-member signatures used in mixing models.

Soil in alpine environments plays a key role in the development of ecosystem services and in order to maintain and preserve this important resource, information is required on processes that lead to soil erosion. Similar to other mountain alpine environments, the Benasque catchment is characterised by temperatures below freezing that can last from November to April, intense rainfall events, typically in spring and autumn, and rugged topography which makes assessment of erosion challenging. Indirect approaches to soil erosion assessment, such as combined model approaches, offer an opportunity to evaluate soil erosion in such areas. In this study (i) the SWAT (Soil and Water Assessment Tool) hydrological and erosion model and (ii) sediment fingerprinting procedures were used in parallel to assess the viability of a combined modelling and tracing approach to evaluate soil erosion processes in the area of the Posets-Maladeta Natural Park (central Spanish Pyrenees). Soil erosion rates and sediment contribution of potential sediment sources defined by soil type (Kastanozems/Phaeozems; Fluvisols and Cambisols) were assessed. The SWAT model suggested that, with the highest specific sediment yields, Cambisols are the main source of sediment in the Benasque catchment and Phaeozems and Fluvisols were identified as the lowest sediment contributors. Spring and winter model runs gave the highest and lowest specific sediment yield, respectively. In contrast, sediment fingerprinting analysis identified Fluvisols, which dominate the riparian zone, as the main sediment source at the time of sampling. This indicates the importance of connectivity as well as potential differences in the source dynamic of material in storage versus that transported efficiently from the system at times of high flow. The combined approach enabled us to better understand soil erosion processes in the Benasque alpine catchment, wherein SWAT identified areas of potential high sediment yield in large flood ev

The ability of geochemical fingerprint properties to discriminate between the sediment sources was investigated by conducting the nonparametric Kruskal-Wallis H-test and a stepwise discriminant function analysis (minimization of Wilk’s lambda). This standard procedure selects potential fingerprinting properties as optimum composite fingerprint to characterize and discriminate between sediment sources to the reservoir. Then the contribution of each potential sediment source was assessed by applying a Monte Carlo mixing model to obtain source proportions for the Bara- sona reservoir sediment samples

Detailed information on post-logging sediment dynamics in tropical catchments is required for modelling downstream impacts on communities and ecosystems. Sediment tracing methods, which are potentially useful in extending to the large catchment scale and longer time scales, are tested in primary and selectively logged rainforest catchments of Sabah, Borneo. Selected nutrient (P and N) and trace metal (Ni and Zn) concentrations are shown to discriminate surface, shallow subsurface and deep subsurface sediment sources. Analysis of channel-stored fine-sediment samples and use of an unmixing model allow the relative importance of these vertical sediment sources to be estimated and erosion processes to be inferred for catchments of contrasting size.

Detailed information on post-logging sediment dynamics in tropical catchments is required for modelling downstream impacts on communities and ecosystems. Sediment tracing methods, which are potentially useful in extending to the large catchment scale and longer time scales, are tested in primary and selectively logged rainforest catchments of Sabah, Borneo. Selected nutrient (P and N) and trace metal (Ni and Zn) concentrations are shown to discriminate surface, shallow subsurface and deep subsurface sediment sources. Analysis of channel-stored fine-sediment samples and use of an unmixing model allow the relative importance of these vertical sediment sources to be estimated and erosion processes to be inferred for catchments of contrasting size.

[No abstract available]

Detailed information on post-logging sediment dynamics in tropical catchments is required for modelling downstream impacts on communities and ecosystems. Sediment tracing methods, which are potentially useful in extending to the large catchment scale and longer time scales, are tested in primary and selectively logged rainforest catchments of Sabah, Borneo. Selected nutrient (P and N) and trace metal (Ni and Zn) concentrations are shown to discriminate surface, shallow subsurface and deep subsurface sediment sources. Analysis of channel-stored fine-sediment samples and use of an unmixing model allow the relative importance of these vertical sediment sources to be estimated and erosion processes to be inferred for catchments of contrasting size.

Detailed information on post-logging sediment dynamics in tropical catchments is required for modelling downstream impacts on communities and ecosystems. Sediment tracing methods, which are potentially useful in extending to the large catchment scale and longer time scales, are tested in primary and selectively logged rainforest catchments of Sabah, Borneo. Selected nutrient (P and N) and trace metal (Ni and Zn) concentrations are shown to discriminate surface, shallow subsurface and deep subsurface sediment sources. Analysis of channel-stored fine-sediment samples and use of an unmixing model allow the relative importance of these vertical sediment sources to be estimated and erosion processes to be inferred for catchments of contrasting size.

Detailed information on post-logging sediment dynamics in tropical catchments is required for modelling downstream impacts on communities and ecosystems. Sediment tracing methods, which are potentially useful in extending to the large catchment scale and longer time scales, are tested in primary and selectively logged rainforest catchments of Sabah, Borneo. Selected nutrient (P and N) and trace metal (Ni and Zn) concentrations are shown to discriminate surface, shallow subsurface and deep subsurface sediment sources. Analysis of channel-stored fine-sediment samples and use of an unmixing model allow the relative importance of these vertical sediment sources to be estimated and erosion processes to be inferred for catchments of contrasting size.

[No abstract available]

[No abstract available]

Detailed information on post-logging sediment dynamics in tropical catchments is required for modelling downstream impacts on communities and ecosystems. Sediment tracing methods, which are potentially useful in extending to the large catchment scale and longer time scales, are tested in primary and selectively logged rainforest catchments of Sabah, Borneo. Selected nutrient (P and N) and trace metal (Ni and Zn) concentrations are shown to discriminate surface, shallow subsurface and deep subsurface sediment sources. Analysis of channel-stored fine-sediment samples and use of an unmixing model allow the relative importance of these vertical sediment sources to be estimated and erosion processes to be inferred for catchments of contrasting size.

The South Coast Technology R-1 Electric is a standard VW Rabbit that has been converted to an electric Vehicle. The SCT R-1 Electric was tested by the US Army Mobility Equipment Research and Development Command as part of a Department of Energy project to characterize the state-of-the-art and to verify Manaufacturer certification of the electric vehicle. The R-1 Electric performance test results are presented in this report. The SCT R-1 Electric is powered by 18 lead-acid batteries, has a separately excited moter, transistorized field chopper controller, regenerative braking, and a 4-speed manual transmission.

The Jet Industries Electra Van 600 is a Subaru Van which has been converted to an electric vehicle. It was tested by MERADCOM as part of a Department of Energy project to verify conformity to performance standards of electric vehicles. The Electra Van 600 test results are presented in this report. The 600 Van is powered by 17 6-volt lead-acid batteries through an SCR Controller to a series-wound 20-hp d.c. motor. It has torsion bar suspension with hydraulic shocks and is equipped with drum-type hydraulic brakes front and rear. It does not have regenerative braking. (Author)

The GE-100 Centennial electric vehicle is a one-of-a-kind prototype. Results of performance tests, speed, acceleration, gradeability, range, and efficiencies are presented. The GE-100 is powered by eighteen 6-volt lead-acid batteries driving a 16.3-kW d.c. series motor through an EV-1C controller. The motor drives the wheels through a chain drive to the differential. No regenerative braking was provided. (Author)

The Electra-Van 1000P is a Chrysler Corp. pickup truck which has been converted to an electric vehicle. It was tested as part of a Department of Energy demonstration program. The Electra-Van 1000P performance test results are presented. The 1000P is powered by 24 6-volt lead acid batteries through an SCR Controller to a 37-hp electric motor. It has a manual 4-speed transmission and front disc and rear drum brakes. It does not have regenerative braking.

The Electra Van Model 1000, an electric half-ton multipurpose van, was tested at MERADCOM as part of a Department of Energy project to characterize the state-of-the-art of electric vehicles. The Electra Van is manufactured in Austin, Texas by Jet Industries, Inc. It is powered by 24, 6-volt batteries that are connected to the motor through an SCR controller actuated by a foot pedal to control motor speed. The 28-horsepower motor drives the rear wheels through a three-speed manual transmission. No regenerative braking is provided. (Author)

The Battronic Mini Van Model M065MLB, an electric two-passenger multipurpose van, was tested at MERADCOM to verify conformity to the Department of Energy Performance Standards for Demonstrations, published in the Federal Register, 30 May 1978, Part V. The Battronic Mini Van is manufactured in Boyertown, Pennsylvania, by Battronic, Inc. It is powered by two 56-volt lead-acid batteries that are connected to the motor through an SCR control actuated by a foot pedal to control motor speed. The 42-horsepower motor drives the rear wheels through a direct drive to the differential. Regenerative braking is provided. (Author)

The Change-of-Pace, and electric four-passenger station wagon, was tested at MERADCOM to verify conformity to the Department of Energy Performance Standards for Demonstrations, published in the Federal Register, 30 May 1978, Part V. The Change-of-Pace is manufactured in Cleveland, Ohio, by Electric Vehicles Associates. It is a converted AMC Pacer station wagon. It is powered by 20 6-volt batteries that are connected to the motor through an SCR controller actuated by a foot pedal to control motor speed. The 22-horsepower motor drives the rear wheels through an automatic transmission. Regenerative braking is provided. (Author)

The Citi-Van Model 611N0003, an electric two-passenger multipurpose van, was tested at the US Army Aberdeen Proving Ground test facilities in Aberdeen, Maryland, as part of a Department of Energy (DOE) project to characterize the state-of-the-art of electric vehicles. The Citi-Van is manufactured in Sebring, Florida, by Sebring Vanguard, Inc. It is powered by eight 6-volt batteries that are connected to the motor through a contactor control actuated by a foot pedal to control motor speed. The 6-horsepower motor drives the rear wheels through a direct drive to the differential. No regenerative braking was provided. (Author)

The Electra-Van, Model 500-108, an electric, quarter-ton, multipurpose van, was tested at the US Army Aberdeen Proving Ground Test Facilities in Aberdeen, Maryland, as part of a Department of Energy (DOE) project to characterize the state-of-the-art of electric vehicles. The Electra-Van is manufactured in Austin, Texas, by Jet Industries, Inc. It is a converted Subaru minivan. It is powered by eighteen, 6-volt batteries that are connected to the motor through an SCR controller actuated by a foot pedal to control motor speed. The 14.2-horsepower motor drives the rear wheels through a four-speed manual transmission. No regenerative braking is provided. (Author

The Daihatsu EH-S40 Van, an electric quarter-ton delivery truck, was tested at the U.S. Army Aberdeen Proving Ground test facilities in Aberdeen, Maryland, as part of a Department of Energy (DOE) project to characterize the state-of-the-art of electric vehicles. The EH-S40 Van performance test results are presented in this report. The EH-S40 Van is manufactured in Osaka, Japan, by Daihatsu Motor Co., Ltd. The van is powered by eight 12-volt batteries that are connected to the motor through an arrangement of contactors operated from a foot pedal. The motor is a compound type with a transistor shunt field control. The motor is connected via a clutch to a four-speed manual transmission. No regenerative braking was provided. (Author), See also AD-A056 927.

The EVA Metro is a four-passenger Renault 12 Sedan that has been converted to an electric vehicle. It was tested as part of a Department of Energy (DOE) project to characterize the state-of-the-art of electric vehicles. The EVA Metro Sedan vehicle performance test results are presented in this report. The EVA Metro is powered by sixteen, 6-volt traction batteries through a silicon-controlled rectifier (SCR) controller actuated by a foot throttle to change the voltage applied to a 10-kW motor. The braking system is a power-assist, hydraulic braking system with front-wheel disk and rear drum. Regenerative braking is not provided.

Soil erosion is a critical problem for pastoralist societies that rely on healthy grazing land for their livelihoods. Previous research suggests that unsustainable land management practice is one of the factors exacerbating soil erosion, and that willingness to adjust this practice is closely linked to community land protection norms. The present research explores approaches to building stronger community norms and intentions linked to mitigating soil erosion among Maasai pastoralists in Northern Tanzania. In particular, we compare two impact approaches based on the information deficit model (exposure to scientific information) and the social identity framework (a group-based discussion). The results demonstrate that the information deficit approach results in stronger perceived land protection norms and, indirectly, stronger intentions, as compared to the discussion-based approach. We discuss contextual features that should be taken into account when interpreting these findings and suggest these may be key for impact approach choices.