Contribution for the derivation of a soil screening value (SSV) for uranium, using a natural reference soil

In order to regulate the management of contaminated land, many countries have been deriving soil screening values (SSV). However, the ecotoxicological data available for uranium is still insufficient and incapable to generate SSVs for European soils. In this sense, and so as to make up for this shortcoming, a battery of ecotoxicological assays focusing on soil functions and organisms, and a wide range of endpoints was carried out, using a natural soil artificially spiked with uranium. In terrestrial ecotoxicology, it is widely recognized that soils have different properties that can influence the bioavailability and the toxicity of chemicals. In this context, SSVs derived for artificial soils or for other types of natural soils, may lead to unfeasible environmental risk assessment. Hence, the use of natural regional representative soils is of great importance in the derivation of SSVs. A Portuguese natural reference soil PTRS1, from a granitic region, was thereby applied as test substrate. This study allowed the determination of NOEC, LOEC, EC20 and EC50 values for uranium. Dehydrogenase and urease enzymes displayed the lowest values (34.9 and ,134.5 mg U Kg, respectively). Eisenia andrei and Enchytraeus crypticus revealed to be more sensitive to uranium than Folsomia candida. EC50 values of 631.00, 518.65 and 851.64 mg U Kg were recorded for the three species, respectively. Concerning plants, only Lactuca sativa was affected by U at concentrations up to 1000 mg U kg1. The outcomes of the study may in part be constrained by physical and chemical characteristics of soils, hence contributing to the discrepancy between the toxicity data generated in this study and that available in the literature. Following the assessment factor method, a predicted no effect concentration (PNEC) value of 15.5 mg kg21dw was obtained for U. This PNEC value is proposed as a SSV for soils similar to the PTRS1

Natural capital, ecosystem services, and soil change: why soil science must embrace an ecosystems approach

Soil is part of the Earth's life support system, but how should we convey the value of this and of soil as a resource? Consideration of the ecosystem services and natural capital of soils offers a framework going beyond performance indicators of soil health and quality, and recognizes the broad value that soil contributes to human wellbeing. This approach provides links and synergies between soil science and other disciplines such as ecology, hydrology, and economics, recognizing the importance of soils alongside other natural resources in sustaining the functioning of the Earth system. We articulate why an ecosystems approach is important for soil science in the context of natural capital, ecosystem services, and soil change. Soil change is defined as change on anthropogenic time scales and is an important way of conveying dynamic changes occurring in soils that are relevant to current political decision-making time scales. We identify four important areas of research: (i) framework development; (ii) quantifying the soil resource, stocks, fluxes, transformations, and identifying indicators; (iii) valuing the soil resource for its ecosystem services; and (iv) developing decision-support tools. Furthermore, we propose contributions that soil science can make to address these research challenges

Ecosystem services: A useful concept for soil policy making!

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Nitrogen cycling from increased soil organic carbon contributes both positively and negatively to ecosystem services in wheat agro-ecosystems

Soil organic carbon (SOC) is an important and manageable property of soils that impacts on multiple ecosystem services through its effect on soil processes such as nitrogen (N) cycling and soil physical properties. There is considerable interest in increasing SOCconcentration in agro-ecosystems worldwide. In some agro-ecosystems, increased SOC has been found to enhance the provision of ecosystem services such as the provision of food. However, increased SOC may increase the environmental footprint of some agro-ecosystems, for example by increasing nitrous oxide emissions. Given this uncertainty, progress is needed in quantifying the impact of increased SOCconcentration on agro-ecosystems. Increased SOC concentration affects both N cycling and soil physical properties (i.e., water holding capacity). Thus, the aim of this study was to quantify the contribution, both positive and negative, of increased SOC concentration on ecosystem services provided by wheat agro-ecosystems. We used the Agricultural Production Systems sIMulator (APSIM) to represent the effect of increased SOC concentration on N cycling and soil physical properties, and used model outputs as proxies for multiple ecosystem services from wheat production agro-ecosystems at seven locations around the world. Under increased SOC, we found that N cycling had a larger effect on a range of ecosystem services (food provision, filtering of N, and nitrous oxide regulation) than soil physical properties. We predicted that food provision in thse agro-ecosystems could be significantly increased by increased SOCconcentration when N supply is limiting. Conversely, we predicted no significant benefit to food production from increasing SOC when soil N supply (from fertiliser and soil N stocks) is not limiting. The effect of increasing SOC on N cycling also led to significantly higher nitrous oxide emissions, although the relative increase was small. We also found that N losses via deepdrainage were minimally affectedby increasedSOCin the drylandagro-ecosystems studied, but increased in the irrigated agro-ecosystem. Therefore, we show that under increased SOC concentration, N cycling contributes both positively and negatively to ecosystem services depending on supply, while the effects on soil physical properties are negligible

A review of methods, data, and models to assess changes in the value of ecosystem services from land degradation and restoration

This review assesses existing data, models, and other knowledge-based methods for valuing the effects of sustainable land management including the cost of land degradation on a global scale. The overall development goal of sustainable human well-being should be to obtain social, ecologic, and economic viability, not merely growth of the market economy. Therefore new and more integrated methods to value sustainable development are needed. There is a huge amount of data and methods currently available to model and analyze land management practices. However, it is scattered and requires consolidation and reformatting to be useful. In this review we collected and evaluated databases and computer models that could be useful for analyzing and valuing land management options for sustaining natural capital and maximizing ecosystem services. The current methods and models are not well equipped to handle large scale transdisciplinary analyses and a major conclusion of this synthesis paper is that there is a need for further development of the integrated approaches, which considers all four types of capital (human, built, natural, and social), and their interaction at spatially explicit, multiple scales. This should be facilitated by adapting existing models and make them and their outcomes more accessible to stakeholders. Other shortcomings and caveats of models should be addressed by adding the ‘human factor’, for instance, in participatory decision-making and scenario testing. For integration of the models themselves, a more participatory approach to model development is also recommended, along with the possibility of adding advanced gaming interfaces to the models to allow them to be “played” by a large number of interested parties and their trade-off decisions to be accumulated and compared.© 2015 Publishe

Soil Functions—An Introduction

It is now widely recognised that soils not only provide food but in addition, they deliver a wide range of ecosystem services to society. The EU Thematic Strategy on Soils (2006) identified seven ‘environmental, economic, social and cultural functions’. In research studies from Ireland, these ecosystem services have been rearranged into the following five main soil functions for agricultural land (1) primary production, (2) water purification and regulation, (3) carbon storage and sequestration, (4) habitat for intrinsic and functional biodiversity and (5) the cycling and provision of nutrients. In addition, soils also provide two ancillary functions, namely: (6) a platform for infrastructure (e.g. roads, buildings) and (7) an outdoor archive of archaeological heritage. In principle, all soils perform each of these functions simultaneously. However, the extent to which each function is delivered depends in the first instance, on land use. For example, the functionality of arable soils is characterised by primary production and nutrient cycling. Second, the functionality of soils depends on soil properties. The dominant soil properties in Atlantic climates relate to soil moisture dynamics, specifically the occurrence of excess soil water. Quantifying soil functions is difficult as each soil function encompasses a set of processes which may be altered through management which could alter the delivery of another function, resulting in potentially a synergy or a trade-off between functions. Therefore, proxy-indicators are used to estimate the extent to which a soil provides the five functions. The functionality of soils worldwide is threatened by unsustainable management practices and in Europe, there are eight main threats to soil functionality