Effect of soil properties on arsenic fractionation and bioaccessibility in cattle and sheep dipping vat sites

Historical use of high arsenic (As) concentrations in cattle/sheep dipping vat sites to treat ticks has resulted in severe contamination of soil and groundwater with this Group-A human carcinogen. In the absence of a universally applicable soil As bioaccessibility model, baseline risk assessment studies have traditionally used the extremely conservative estimate of 100% soil As bioaccessibility. Several in-vitro, as well as, in-vivo animal studies suggest that As bioaccessibility in soil can be lower than that in water. Arsenic in soils exists in several geochemical forms with varying degree of dissolution in the human digestive system, and thus, with highly varying As bioaccessibility. Earlier batch incubation studies with As-spiked soils have shown that As bioaccessibility is a function of soil physicochemical properties. We selected 12 dipping vat soils collected from USA and Australia to test the hypothesis that soil properties exert a significant effect on As bioaccessibility in As-contaminated sites. The 12 soils varied widely in terms of soil physico-chemical properties. They were subject to an As sequential fractionation scheme and two in-vitro tests (IVGS and IVGIA) to simulate soil As bioavailability in the human gastrointestinal system. Sequential As fractionation results showed that the majority of the As measured in the dipping vat soils resided either in the Fe/Al hydroxide fraction, or the Ca/Mg fractions, or in the residual fraction. Water-extractable As fraction of the 12 soils was typically <10% of the total, reaching values up to 23%, indicating minimal leaching potential, and hence, lower risk of As-contamination from exposure to groundwater, typically used as drinking water in many parts of the world. Partial individual correlations and subsequent multiple regression analyses suggested that the most significant soil factors influencing As bioaccessibility were total Ca+Mg, total P, clay content and EC. Collectively, these soil properties were able to explain 85 and 86% of the variability associated with the prediction of bioaccessible As, using IVGS and IVGIA in-vitro tests, respectively. This study showed that specific soil properties influenced the magnitude of soil As bioaccessibility, which was typically much lower than total soil-As concentrations, challenging the traditional risk assessment guideline, which assumes that soil As is 100% bioaccessible. Our study showed that total soil As concentration is unlikely to provide an accurate estimate of human health risk from exposure to dipping vat site soils.     

Land use influence on 137Cs levels in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.)

The environmental influence on Chernobyl-derived 137Cs levels in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) was revealed using partial least-squares regression (PLS). The 53 environmental predictors used describe land use in catchment areas, various catchment area and lake characteristics, lake water chemistry, and fish stock composition. The study showed a profound effect of land use on the 137Cs levels in fish. Radiocaesium deposited on arable land was retained in the soil to a greater extent than was 137Cs deposited on wetlands, which more easily leached out to the lake ecosystems. The 137Cs deposition close to the lakes had a more pronounced effect on 137Cs levels in the fish than did more distant deposition. The radiocaesium bioavailability is mainly governed by lake water cation content, as hardwater lakes had significantly lower 137Cs content in fish. Resuspension of 137Cs contaminated sediments only had a limited influence on the observed levels in fish.     

A review of regulatory decisions for environmental protection: part I - challenges in the implementation of national soil policies

Since many soil studies have already revealed the possible risks to human health and the environment arising from contaminated soils it is therefore crucial to preserve soil quality under current and future conditions. In the last three decades a number of countries already introduced national policies and practices for the management of contaminated sites, and in 2002, an EU Thematic Strategy for Soil Protection was proposed by the European Commission. In this paper we review and analyse several national contaminated land policy regimes already in place in order to assess common elements and to identify specific needs in the development of national soil policies. We propose a framework that combines the D-P-S-I-R structure of policy evaluation with the Source-Pathway-Receptor approach to health risk assessment to support the development of effective country specific regulatory decisions for managing contaminated land in countries where these are yet to be implemented. The framework proposed allows decision makers to effectively use available information and to identify existing data gaps. As a result it is apparent that while there are technical aspects of site characterisation, risk assessment and remediation processes that could be commonly implemented at an EU level there are certain trans-scientific aspects that require political choices and need to be customized by EU Member States.     

Assessment of cadmium bioaccessibility to predict its bioavailability in contaminated soils

In vitro assays have been developed to determine metal bioaccessibility in contaminated soils; however, their application to Cd is limited. To assess their suitability to determine Cd relative bioavailability (RBA), Cd-RBA in 12 contaminated soils containing 3.00–296 mg kg^− 1 Cd were determined using a mouse model and compared with Cd bioaccessibility data based on four assays including the UBM, SBRC, IVG, and PBET. After being administered feed amended with soil or CdCl₂ for 10-day, the Cd concentrations in the mouse liver and/or kidneys were used as biomarkers to estimate Cd-RBA. Cd-RBA was comparable at 34–90% and 40–78% based on mouse liver and kidneys with RSD of 7.10–8.99%, and 37–84% based on mouse liver plus kidneys with lower RSD of 5.8%. Cadmium bioaccessibility in soils varied with assays, with 61–99, 59–103, 54–107, and 35–97% in the gastric phase and 20–56, 38–77, 42–88, and 19–64% in the intestinal phase of the UBM, SBRC, IVG and PBET assays. Based on the combined biomarker of liver plus kidneys, better correlation was observed for PBET (r² = 0.61–0.70) than those for IVG, UBM and SBRC assays (0.12–0.52). The monthly Cd intake in children was 0.24–23.9 μg kg^− 1 using total Cd concentration in soils, which was reduced by 43% to 0.18–12.3 μg kg^− 1 using bioavailable Cd. Our data suggest it is important to consider Cd-RBA to assess risk associated with contaminated soils and the PBET may have potential to predict Cd-RBA in contaminated soils.     

A review of regulatory decisions for environmental protection: part II - the case-study of contaminated land management in Portugal

This paper provides a case-study analysis of the challenges in the implementation of national soil policies, which was developed by the authors in Part I of the review of regulatory decisions for environmental protection [Rodrigues SM, Pereira ME, Ferreira da Silva E, Hursthouse A, Duarte AC. A review of regulatory decisions for environmental management: Part I-challenges in the implementation of national soil policies. Environ Int 2009. doi:10.1016/j.envint.2008.08.007]. The Portuguese case was selected as a case-study since specific regulatory decisions for contaminated land management are still in the early stages of development. Given the gap between the situation at the EU level and the state of Portuguese soil policy development, it is of merit to consider national contaminated land policy regimes already in place within the EU and to see if these provide a suitable basis to define the main challenges and research needs for the implementation of a Portuguese contaminated land management strategy. A framework combining the D-P-S-I-R (drivers-pressures-sources-impacts-responses) structure of policy evaluation with the Source-Pathway-Receptor approach to health risk assessment is proposed to derive an effective regulatory framework for managing contaminated land in Portugal, using available information and only to develop new data and research where knowledge gaps exist. Funding site clean-up and assigning liability were identified as relevant factors currently hampering site remediation. Most relevant research needs for the development of contaminated land management practices in Portugal are those associated to the definition of a risk assessment framework and setting guidelines for the evaluation of risks posed to both humans and ecosystems. Other relevant and innovative features are the integration of soil function analysis into site investigations and the definition of a framework that combines risk assessment with soil function analysis. The analysis of the Portuguese case also provides insight into the discussions needed for the effective development of regulatory decisions for contaminated land management in countries with no history of implementing specific soil policies.     

The effect of ageing on the bioaccessibility and fractionation of cadmium in some typical soils of China

Ingestion of contaminated soil has been recognized as an important exposure pathway of cadmium (Cd) for humans, especially for children through outdoor hand-to-mouth activities. The effect of ageing process following the input of Cd into soil on the bioaccessibility of Cd in five typical soils of China was investigated using physiologically based in vitro test in this study. A sequential extraction procedure was employed with attempt to identify the bioaccessible fraction(s) of Cd in soils. The bioaccessibility of Cd in strongly acidic (approximately pH 4.5) soils reached nearly steady levels (76.5-76.9% and 52.0-52.6% in the gastric and small intestinal phases, respectively) after a sharp decline in the first week of ageing. In contrast, the bioaccessibility of Cd in higher pH (>6.0) soils was found to be much lower (53.3-72.7% and 29.9-43.4% in gastric and small intestinal phases, respectively) and took 2 weeks of ageing to reach steady levels. The freshly spiked Cd was more labile than native Cd. The main proportion of spiked Cd was found in exchangeable Cd which was higher in strongly acidic soils (68.6-71.8%) than in higher pH soils (53.4-61.4%) at day 120 after a sharp decline to the nearly steady state in the first 1 and 2 weeks, respectively. Significant correlations between Cd bioaccessibility and either water soluble and exchangeable Cd individually, or the sum of water soluble and exchangeable Cd throughout the incubation period for all soils, indicate that these forms of Cd are likely to constitute the main proportion of bioaccessible Cd in soils.     

基于知识与规则的土地利用信息分层提取研究——以南京市都市区为例

为了克服利用统一分类模型难以有效提高土地利用分类精度的问题,为土地利用/覆被定性、定量信息的提取提供一种高精度、高效率的提取方法,将分层信息提取法和基于知识规则的信息提取方法相结合,基于对南京市都市区的土地利用时空特点和研究区TM影像数据中各地类波谱信息的分析,结合了地类提取指数模型、DEM数据、城市建成区边界等,充分利用地学先验知识,设计了一套土地信息分层提取的流程,对土地利用信息进行了提取。利用该方法对2012年南京市都市区的土地利用/土地覆被信息提取的总体精度达到了88.67%,Kappa系数达到了0.85。实践证明,基于知识与规则的土地利用信息分层提取方法提取精度较高,适用性强,对其他地区的土地利用/覆被信息分类提取也有一定的借鉴意义。     

鄱阳湖流域城市洪涝灾害风险及土地类型调整策略研究 ——以景德镇市为例

在全球气候变化和人类活动影响下，流域内城市洪涝灾害发生的频率、强度及其造成的损失日益加剧，更好的揭示洪涝灾害风险的时空演变规律对不同流域下城市防灾减灾具有重要意义。基于流域城市洪涝灾害风险的形成过程，从致灾因子、孕灾环境、承灾体、防灾减灾能力4个方面选取指标，构建了基于格网的流域城市小尺度洪涝灾害风险评价模型，并以景德镇市城区为例，将空间风险定量计算，分析了城市洪涝风险的时空分异特征，最后提出土地利用类型的调整策略。结果表明:从空间上，城区洪涝灾害风险极大值与极小值差值存在较大的差异，呈现由昌江、南河、西河等河流为中心向四周逐渐减小的方向性变化，不同区域的风险波动性幅度不同，社会经济发展水平较高的珠山区昌江沿岸区域为景德镇城区的洪涝灾害高风险区，西部、西南部山区以及东部乡镇由于地势较高，风险水平较低。从时间上，景德镇市城区的洪涝灾害风险最大值呈下降趋势，南部洪涝灾害风险整体变小，但风险集中程度不断加剧，城区西部风险值有小幅度的上升；针对不同的区域特征，通过两种方案对城区内洪涝灾害易涝典型地区进行土地利用类型调整，两个区域风险分别从0.606与0.610降低到0.561与0.571。     

Regional risk assessment for contaminated sites Part 3: Spatial decision support system

Large scale (e.g. regional or national) assessments of contaminated sites may be very costly in terms of investigation and methodological (i.e. risk assessment procedures) requirements and may produce a quantity of information that usually discourages examination by decision-makers. Moreover, most of the existing tools effectively support local environmental risk assessment and management, but lack the capabilities of larger scale analysis, not mentioning the absence of the relevant component of socio-economic prioritization. To respond to the concerns and the management needs of experts and decision makers, the Spatial decision support sYstem for Regional rIsk Assessment of Degraded land (SYRIADE DSS) was developed and is presented according to its three modules: Regional Risk Assessment, Socio-economic Assessment and Integrated Assessment, respectively. The system allows to rank potentially contaminated sites for priority of investigation, when no information on characterization and risk by site specific methodologies is available. This GIS-based system embeds an innovative spatial and relative risk assessment procedure, and proposes the integrated analysis of different data (environmental and socio-economic) for the concerned sites, eliciting when necessary experts' knowledge and stakeholders' values (through Multi Criteria Decision Analysis, MCDA, methodologies). The application to a Polish case-study shows the performance and the flexibility of the system in investigating and mapping (potentially) contaminated sites at the regional scale.     

Assessment of groundwater potential in Tirukalukundram block of southern Chennai Metropolitan Area

Groundwater is an important resource in all major urban centres. Continuous extraction leads to degradation and depletion in the water quality which can be protected by selecting proper groundwater recharging techniques. The present study aims to determine the groundwater potential by integrating the remote sensing and geographic information system which helps to identify the locations which are in critical stage and immediate steps can be taken to recharge the groundwater. Thirukalukundram block of Kanchipuram district in Tami Nadu, India, has been chosen as study area. To demarcate the groundwater potential zone, surface attributes such as geomorphology, land use/land cover, contour map, drainage density and sub-surface attributes such as lineaments and soil maps are created using satellite imageries, toposheet, soil and geomorphology data of the study area. The thematic maps prepared using geographic information system and weights have been assigned to the attributes by considering the influence on the storage capacity of groundwater. Four categories of groundwater potential zones such as below low, low, moderate and high have been classified. From the analysis, 5% along the coastal plain area covers high groundwater potential zone, 20% of the area towards north-west and south-west hold moderate groundwater potential. 60% of the total area hold low groundwater potential zone which are located towards south-west direction. 15% of the study area contains below low groundwater potential zone in parts of south-west direction. This study helps to identify the suitable locations for extraction and recharge of groundwater.     

Treatment of uncertainty and developing conceptual models for environmental risk assessments and radioactive waste disposal safety cases

The common approach to performing quantitative risk assessments in the contaminated land industry in the UK lacks a formal methodology for the treatment of the full range of uncertainties and for documenting decisions regarding the development of conceptual models and the selection of computer codes. The approach presented here represents an alternative, more detailed, and systematic approach for developing conceptual models and addressing uncertainties when undertaking contaminated land risk assessments. It is intended that the advantages of this approach are recognised by practitioners in the contaminated land industry and adopted, where appropriate, to help improve the quality of contaminated land risk assessments. The identification of features, events, and processes (FEPs) has been applied to safety assessments of deep geological and near-surface disposal of radioactive wastes. One of the primary benefits of using this approach is in the development of conceptual models. The approach identifies the FEPs that need to be addressed during the development of conceptual models and in the selection of suitable computer codes that can be used to represent the conceptual models. This approach has been applied by BNFL at the low-level radioactive waste disposal site at Drigg in Cumbria and is currently being adopted for a contaminated land study at the Sellafield site, also in Cumbria. This paper presents the advantages of using FEPs in the development of conceptual models and the treatment of uncertainties. The paper also discusses the application of this approach to contaminated land studies and provides an example to demonstrate the application of the approach. BNFL's approach at the Drigg site involves the identification of components (features) and phenomena (events and processes) that govern interactions and dependencies between the components by arranging them in a matrix format.     

平原地区复合土地利用系统中氮磷流失敏感区界定——以浙江大学华家池校区为例

为正确识别平原地区复合土地利用系统中氮磷流失敏感区,利用美国农业部水土保持局设计的水文模型中的CN值描述地表状况,反映不同土地利用条件下下垫面对土壤氮、磷流失的影响;运用等标污染负荷计算方法评估不同类型污染源强度;建立了复合土地利用系统中土壤氮、磷流失敏感区的综合指数评价体系.构建的氮、磷流失评价方法在浙江大学华家池校区的应用评价结果表明,氮磷流失敏感性高的区块主要为研究区内的居民区、畜牧场和一些施肥量大的种植区,而敏感性最低的区块集中在具有良好植被覆盖的绿化区.高的污染源和高的迁移因子叠加区构成了高的流失敏感区.     

The influence of clay mineralogy on the mobility of radiocaesium in upland soils of NW Italy

137Cs extraction experiments were performed on 14 contaminated soils from NW Italy with different characteristics and mineralogical composition. Solutions of HCl (pH = 0.5) and buffered EDTA/ammonium acetate (Lakanen solution) were used to assess bioavailability. The results show that less than 2% of 137Cs is available for leaching and/or root uptake. Even within a complex natural system it was possible to identify the amount of swelling clays (vermiculite + smectite) as the main control on Cs mobility under acidic conditions. The ammonium ion appears to be effective in desorbing Cs and its role is briefly discussed in terms of crystal chemistry. The relevance of mineralogy in assessing soil vulnerability is underlined.     

基于PCA方法的长江口滩涂围垦区土地利用动态综合评价及驱动力

基于1987、1995、2000和2006年长江口TM、ETM遥感影像,采用“空间代时间”和主成分分析（PCA）综合评价模型的方法,对长江口奉贤不同围垦年限土地利用动态特征进行了综合评价分析。利用南汇围垦区土地利用动态变化对综合评价的结果进行验证。表明：（1）围垦区土地利用程度指数随着围垦年限增加而呈线性升高趋势（〖WTBX〗R2〖WTBZ〗=0457 7）,GM（土地利用多样性指数）呈现指数上升趋势并在围垦后35~40 a达到稳定态;（2）PCA土地利用综合评价指数（〖WTBX〗F〖WTBZ〗）与农耕用地正相关（水田>大棚用地>旱地>林地>园地）,与反映滨海特征类型（养殖塘>草地>开放水域>光滩）呈负相关;（3）土地利用PCA综合评价指数（〖WTBX〗F〖WTBZ〗）随围垦年限增加呈现对数增长（〖WTBX〗R2=0511 9）〖WTBZ〗并在围垦后40 a左右达到稳定态,回归分析表明〖WTBX〗F〖WTBZ〗值能很好反映土地利用程度指数（〖WTBX〗L〖WTBZ〗）和多样性指数（〖WTBX〗GM〖WTBZ〗）的变化趋势;(4)不同围垦年限土地利用动态变异驱动力：人为因素>自然因素。     

Assessment of the effectiveness of different phosphorus fertilizers to remediate Pb-contaminated soil using in vitro test

The addition of P-containing amendments was found to effectively reduce the bioaccessibility of Pb in soils to the human, using an in vitro test. For all treatments with P additions, the removal of soluble Pb in the small intestinal phase was observed. The effectiveness of various P treatments in the small intestinal phase generally followed this order at the equivalent P addition level: hydroxyapatite (HA)>phosphate rock (PR)>HA+single super-phosphate (SSP)>SSP. The relatively low effectiveness of P amendments at the gastric phase may be explained by the high solubility of pyromorphite at relatively low pH of 1.7, compared with that at the neutral small intestinal pH. Single super-phosphate showed the best performance in minimizing the bioaccessibility of Pb in the gastric phase, possibly due to its highest solubility at pH 1.7. Single super-phosphate showed the best performance in minimizing the bioaccessibility of Pb in gastric phase, possibly due its highest solubility at pH 1.7. However, in the small intestinal phase, SSP appears to be the least effective amendment, possibly due to its lowest Ca supply level to replace Pb form exchangeable sites, as reflected by its lowest molar Ca/P ratio of 1:2. The disagreement of the sequential extraction results with that of the in vitro test results indicated that the sequential extraction was not suitable for the assessment of the effect of P addition on minimizing the bioaccessibility of Pb to human due to the formation of pyromorphite during the extraction procedure. Results from this study also suggested that the time required for the in vitro test might be shortened for fast screening.     

The use of molecular techniques to characterize the microbial communities in contaminated soil and water

Traditionally, the identification and characterization of microbial communities in contaminated soil and water has previously been limited to those microorganisms that are culturable. The application of molecular techniques to study microbial populations at contaminated sites without the need for culturing has led to the discovery of unique and previously unrecognized microorganisms as well as complex microbial diversity in contaminated soil and water which shows an exciting opportunity for bioremediation strategies. Nucleic acid extraction from contaminated sites and their subsequent amplification by polymerase chain reaction (PCR) has proved extremely useful in assessing the changes in microbial community structure by several microbial community profiling techniques. This review examines the current application of molecular techniques for the characterization of microbial communities in contaminated soil and water. Techniques that identify and quantify microbial population and catabolic genes involved in biodegradation are examined. In addition, methods that directly link microbial phylogeny to its ecological function at contaminated sites as well as high throughput methods for complex microbial community studies are discussed.     

Sketching sustainable land use in Europe by 2040: a multi-stakeholder participatory approach to elicit cross-sectoral visions

The continuously growing global demands on a finite land resource will require better strategic policies and management of trade-offs to avoid conflicts between different land-use sectors. Visions of the future can support strategic planning by stimulating dialogue, building a consensus on shared priorities and providing long-term targets. We present a novel approach to elicit stakeholder visions of future desired land use, which was applied with a broad range of experts to develop cross-sectoral visions in Europe. The approach is based on (i) combination of software tools and facilitation techniques to stimulate engagement and creativity; (ii) methodical selection of stakeholders; (iii) use of land attributes to deconstruct the multifaceted sectoral visions into land-use changes that can be clustered into few cross-sectoral visions, and (iv) a rigorous iterative process. Three cross-sectoral visions of sustainable land use in Europe in 2040 emerged from applying the approach in participatory workshops involving experts in nature conservation, recreation, agriculture, forestry, settlements, energy, and water. The three visions—Best Land in Europe, Regional Connected and Local Multifunctional—shared a wish to achieve a land use that is sustainable through multifunctionality, resource use efficiency, controlled urban growth, rural renewal and widespread nature. However, they differ on the scale at which land services are provided—EU-wide, regional or local—reflecting the land-sparing versus land-sharing debate. We discuss the usefulness of the approach, as well as the challenges posed and solutions offered by the visions to support strategic land-use planning.

     

Regional risk assessment for contaminated sites Part 2: Ranking of potentially contaminated sites

Environmental risks are traditionally assessed and presented in non spatial ways although the heterogeneity of the contaminants spatial distributions, the spatial positions and relations between receptors and stressors, as well as the spatial distribution of the variables involved in the risk assessment, strongly influence exposure estimations and hence risks. Taking into account spatial variability is increasingly being recognized as a further and essential step in sound exposure and risk assessment. To address this issue an innovative methodology which integrates spatial analysis and a relative risk approach was developed. The purpose of this methodology is to prioritize sites at regional scale where a preliminary site investigation may be required. The methodology aimed at supporting the inventory of contaminated sites was implemented within the spatial decision support sYstem for Regional rIsk Assessment of DEgraded land, SYRIADE, and was applied to the case-study of the Upper Silesia region (Poland).The developed methodology and tool are both flexible and easy to adapt to different regional contexts, allowing the user to introduce the regional relevant parameters identified on the basis of user expertise and regional data availability. Moreover, the used GIS functionalities, integrated with mathematical approaches, allow to take into consideration, all at once, the multiplicity of sources and impacted receptors within the region of concern, to assess the risks posed by all contaminated sites in the region and, finally, to provide a risk-based ranking of the potentially contaminated sites.     

Regional risk assessment for contaminated sites part 2: ranking of potentially contaminated sites

Environmental risks are traditionally assessed and presented in non spatial ways although the heterogeneity of the contaminants spatial distributions, the spatial positions and relations between receptors and stressors, as well as the spatial distribution of the variables involved in the risk assessment, strongly influence exposure estimations and hence risks. Taking into account spatial variability is increasingly being recognized as a further and essential step in sound exposure and risk assessment. To address this issue an innovative methodology which integrates spatial analysis and a relative risk approach was developed. The purpose of this methodology is to prioritize sites at regional scale where a preliminary site investigation may be required. The methodology aimed at supporting the inventory of contaminated sites was implemented within the spatial decision support sYstem for Regional rIsk Assessment of DEgraded land, SYRIADE, and was applied to the case-study of the Upper Silesia region (Poland). The developed methodology and tool are both flexible and easy to adapt to different regional contexts, allowing the user to introduce the regional relevant parameters identified on the basis of user expertise and regional data availability. Moreover, the used GIS functionalities, integrated with mathematical approaches, allow to take into consideration, all at once, the multiplicity of sources and impacted receptors within the region of concern, to assess the risks posed by all contaminated sites in the region and, finally, to provide a risk-based ranking of the potentially contaminated sites.