Regulation of Contaminated Soils in Spain - A New Legal Instrument (4 pp)

Background, Aims and Scope   This paper presents the new Spanish regulation on contaminated soils and its scientific basis. The regulation offers a regulatory framework for establishing industrial activities which may result in soil contamination, and presents the methodology for setting the generic reference levels of organic pollutants.Legal Framework   The Spanish regulation on contaminated soils is derived from the waste legislation and covers 101 industrial activities, as well as facilities handling significant amounts of hazardous chemicals (over 10,000 kg per year) or fuel (300,000 l fuel per year or storing 50,000 l fuel at any time). The regulatory framework includes initial declarations and a tiered system for selecting those soils requiring a proper site-specific risk assessment.Scientific Basis   The regulation is risk based, and covers human and environmental risks. The human health risk assessment focuses on chemical analysis; the selection of relevant exposure routes is associated to the soil uses. The environmental risk assessment includes chemical analysis and direct toxicity testing, and covers three main ecological receptors: Soil organisms, associated aquatic systems and terrestrial vertebrates. Low-risk threshold concentrations are established as generic reference levels; if exceeded, a site-specific risk assessment is required. The detection of a very high level of acute toxicity of soil or leachates led to the declaration of the soil as contaminated due to the capacity for contaminating the adjacent areas.Conclusion   Overall, the Spanish regulation offers a balance for combining regulatory needs, proper scientific basis and practicability. The use of European risk assessment protocols and the European legal framework would facilitate the pan-European extrapolation of this approach. The inclusion of direct toxicity testing as a legal method for classifying a soil as contaminated is considered a key element.     

Selenium in agriculture: a nutrient or contaminant for crops?

Selenium (Se) is an essential nutrient for animals, humans, and microorganisms, but its role in the plants needs further exploration. It is considered beneficial at low levels, but is toxic at higher levels, and there is a fine boundary between these concentrations. Generally, Se levels less than 1 mg kg^?1 have been found to be beneficial for the plants while higher levels cause toxicity in most of the agricultural crops. At low concentrations, Se can act as a plant growth regulator, antioxidant, anti-senescent, abiotic stress modulator, and defensive molecule against pathogens in plants. At higher concentrations, plants show various toxic symptoms, which include stunting of growth, chlorosis, withering, and drying of leaves, decreased protein synthesis premature and even death of the plant. The roles of selenium as enhancer and inhibitor of plant growth in various agricultural crops are discussed here with recent updates. Biofortification of some crops with Se using agronomic and genetic approaches is being explored to cultivate them in the regions having Se-deficiency in foods. Strategies of phytoremediation of Se in hyperaccumulators and transgenic plants overexpressing enzyme/proteins to increase Se tolerance are also described.     

某有机化工污染场地土壤与地下水风险评估

以江苏某有机化工污染场地为例,采用美国RBCA(risk based corrective action)风险评估软件,并依据我国《污染场地风险评估技术导则》(征求意见稿)对模型中的参数进行了本土化设定,开展了典型有机化工类场地土壤与地下水的人体健康与水环境风险评估。结果表明：研究场地土壤污染相对较轻,局部区域存在风险或危害,最大值分别为5.44×10-5和54;地下水污染相对严重,有6个点位存在不同污染物的风险或危害商超标,其中,1,2-二氯乙烷的最大致癌风险高达0.174,氯苯的最大非致癌危害商高达20 586。与保护人体健康的修复目标值相比,保护水环境的值要更为保守。由此,仅基于健康风险的修复仍然可能存在水环境风险,应当予以重视。     

开封市某高校校园地表灰尘重金属分布特征及生态风险评估

   高校校园地表灰尘重金属污染关系到师生健康,探究其地表灰尘重金属环境风险,可为高校校园管理提供数据支持。   采集开封市某高校校园内外地表灰尘52个样品,测定样品中重金属镉（Cd）、铬（Cr）、铜（Cu）、镍（Ni）、铅（Pb）和锌（Zn）的含量,使用地积累指数法和潜在生态风险指数法分析重金属的污染程度和生态风险。    高校地表灰尘重金属Cd、Cr、Cu、Ni、Pb和Zn平均含量分别为1.05、88.36、47.04、29.76、68.72和328.87 mg kg⁻¹,其中Cd和Zn含量分别为当地灰尘背景值的3.49倍和4.26倍。地积累指数分析表明,地表灰尘重金属污染指数平均值由高到低依次为Zn > Cd > Pb > Cu > Cr > Ni,其中Zn与Cd处于偏中度污染,Pb,Cu和Cr处于轻度污染,Ni处于无污染状态。潜在生态风险评价表明,高校地表灰尘中6种重金属综合潜在生态风险指数为144.53,属于“轻微”生态风险等级,其中Cd是该高校地表灰尘中最主要的生态风险影响因子。正定矩阵因子分析法（PMF）表明,Cr和Ni主要来源于成土母质,Cd、Cu、Pb和Zn主要来源于交通、工业污染、大气沉降等复合源。   该高校道路地表灰尘重金属处于轻度到中度污染水平之间,重金属Cd是高校地表灰尘中最主要的污染因子,这些数据可为今后高校校园管理和环境规划提供一些参考。     

茶皂素对污染土壤中重金属的修复作用

采用振荡离心的方法研究了生物表面活性剂茶皂素在不同浓度、pH值和离子强度下对污染土壤中重金属去除效果的影响;并采用BCR法研究了茶皂素处理前后土样中各形态的重金属含量变化。试验结果表明:随着茶皂素浓度的增加,重金属的去除率随之增加,在茶皂素浓度为7%时,对供试土样中重金属的去除率达到最大值,去除率分别为Cd 96.36%,Zn 71.73%,Pb 43.71%,Cu 20.56%;随着土壤环境pH值的增加,重金属的去除率随之减少,适宜的pH范围在5.0左右;离子强度对Pb,Cu的去除效率影响不大,Zn,Cd的去除率随着离子强度的增加而减少。比较茶皂素处理前后土样中重金属各形态含量的变化,发现酸溶态的重金属更易被茶皂素去除,其次为可还原态、可氧化态和残渣态的重金属很难被去除。     

我国南方某典型有机化工污染场地土壤与地下水健康风险评估

以某典型有机化工污染场地为例,开展了多层次健康风险评估,推算了土壤与地下水的筛选值和修复目标值,确定了污染修复范围及修复量。结果表明:土壤与地下水均存在不同程度的有机污染,关注污染物氯仿、四氯化碳、苯、氯苯在0~1 m的土壤修复目标值分别为0.03、0.05、0.35、6.51 mg/kg;1~3 m的土壤修复目标值分别为0.07、0.30、0.90、13.49 mg/kg;3~5 m的土壤修复目标值分别0.14、0.46、1.69、20.45 mg/kg;5~9 m的土壤修复目标值分别为0.25、0.79、2.99、36.27 mg/kg,地下水修复目标值分别为0.32、0.51、3.43、21.80 mg/L。土壤中氯仿、四氯化碳、氯苯的超标点位随深度增加而增多,其风险或危害随之增大;地下水污染区域集中,GW6号点位4种污染物均超标,其中氯仿污染最严重,致癌风险高达1.11×10–3,非致癌危害商为9.8。     

Uptake,Translocation, and Transformation of Arsenic by Four Fern Species in Arsenic‐Spiked Soils

Arsenic (As) toxicity has become a global concern because of the ever‐increasing contamination of water, soil, and crops in many regions of the world. Although most plants are susceptible to As, some ferns are resistant to it and can accumulate As. In this study, four species of ferns, Asplenium nidus (AN), Pteris umbrosia (PU), Polypodium vulgare (PV), and Pteris cretica (PC), were screened for their ability to tolerate and hyperaccumulate As. Ferns were exposed to 120 mg As kg^?1 as sodium arsenate (Na₂HAsO₄) for 50 days under natural sunlight in greenhouse conditions, and the fronds and roots were analyzed for As speciation and selected macronutrients [potassium (K) and phosphorus (P)]. The species of ferns varied widely in their abilities to transport As to the fronds (ranged from 164 to 4820 mg kg^?1 DW) with the greatest frond As concentration found in PU (4820 mg kg^?1). The distribution of soil As fractions indicated that As was mostly bound carbonate (carb) (32.4%) and in the residual fractions (45.1%). Chemical fractionation of As‐spiked soil indicated that the greatest reduction in soil As after growing was in carb As form. Arsenic speciation analysis shows that >82% of the total As in the aboveground biomass is present as the reduced form of As, arsenite [As(III)], which is considered to be the more toxic form. However, in roots, only 60% of the As is present as As(III). Furthermore, among the four species of ferns, PU is the most promising to be used in the remediation of the affected area. Therefore, it is possible to use PU to remediate As‐contaminated soils by repeatedly harvesting its fronds.     

不同富集植物与小麦间作对镉吸收转运的影响

为探究不同富集植物与小麦间作对镉（Cd）吸收转运的影响,分析单间作种植模式下植物的Cd吸收转运差异,设置了小麦分别与龙葵、苋菜、黑麦草的单间作盆栽试验。结果表明,相对于单作小麦,与龙葵、苋菜间作的小麦地上部Cd含量分别显著增加1.35、1.34倍,根部分别显著增加46.3%、25.9%,与黑麦草间作的小麦地上部Cd含量显著增加1.30倍;另外,与龙葵间作的小麦地上部Cd累积量增加1.13倍,与苋菜和黑麦草间作的小麦各部分Cd累积量显著降低。     

植物对~(137)Cs污染土壤的修复

选用了南瓜、油菜、虎尾草、红梗叶甜菜、东升叶甜菜和红甜菜等几种植物,通过盆栽模拟,研究不同活度137Cs污染的广东大亚湾水稻土、浙江秦山水稻土和北京褐土的生物修复作用。结果表明,供试植物在3种土壤上均对137Cs有较强的吸收能力,并随137Cs施入量的增加而增加,两者呈显著正相关r2=0.9989。在污染水平相同的情况下,试验发现,虎尾草、油菜和南瓜所吸收137Cs的比活度随土壤的pH值降低而增加。6种植物的生物修复能力差异较大,综合评价结果为,对137Cs污染土壤修复能力的顺序是:虎尾草>油菜>红梗叶甜菜>南瓜>红甜菜>东升叶甜菜。     

有机氯农药污染场地地下水抽水试验

伴随城市化进程和产业结构调整,我国出现许多污染场地亟待修复。通过某典型有机氯农药污染场地抽水试验论证抽出-处理修复方案应用于该污染场地地下水修复的可行性及获取抽出-处理工程设计所需要的参数,同时监测了特征污染物的浓度变化特征。该污染场地的地下水渗透系数为8.03 m·d-1,抽水井影响半径为117.1 m,长期抽水试验获得的单口井抽水量不低于170 m3·d-1,回灌速度达到7 m3·h-1。结果表明：该污染场地实施抽水是可行的,地下水量满足后续抽出-处理修复工程,可通过自来水回灌减缓修复过程抽水量下降趋势,但此过程也影响地下水的流动方向。同时,抽水过程可抽出大量的污染物,越靠近污染区域,抽提污染物的效果越明显;随着抽水的进行,污染物的浓度总体显现降低的趋势。此外,自来水回灌可稀释地下水中的污染物。     

印度热带森林干旱扰动土壤的微生物碳, 氮, 磷的研究

Variations in microbial biomass C (MB-C),N (MB-N) and P (MB-P) along a gradient of different dominant vegeta- tion covers (natural forest,mixed deciduous forest,disturbed savanna and grassland ecosystems) in dry tropical soils of Vindhyan Plateau,India were studied from January 2005 to December 2005.The water holding capacity,organic C,total N,total P and soil moisture content were comparatively higher in forest soils than in the savanna and grassland sites.Across different study sites the mean annual MB-C,MB-N and MB-P at 0-15 cm soil depth varied from 312.05 ± 4.22 to 653.40 ± 3.17,32.16 ± 6.25 to 75.66 ± 7.21 and 18.94 ± 2.94 to 30.83 ± 23.08 μg g ?1 dry soil,respectively.At all the investigated sites,the maximum MB-C,MB-N and MB-P occurred during the dry period (summer season) and the minimum in wet period (rainy season).In the present study,soil MB-C,MB-N and MB-P were higher at the forest sites compared to savanna and grassland sites.The differences in MB-C,MB-N and MB-P were significant (P 0.001) among sites and seasons.The MB-C (P 0.0001),MB-N (P 0.001) and MB-P (P 0.0001) were positively correlated with organic C,while the relationship between soil moisture and MB-C,MB-N and MB-P (P 0.001,P 0.01 and P 0.0001,respectively) was negative.The decreasing order of MB-C,MB-N and MB-P along study ecosystems was natural forest mixed deciduous forest savanna grassland.The results suggested that deforestation and land use practices (conversion of forest into savanna and grassland) caused the alterations in soil properties,which as a consequence,led to reduction in soil nutrients and MB-C,MB-N and MB-P in the soil of disturbed sites (grassland and savanna) compared to undisturbed forest ecosystems.     

河套灌区根系层-深层土壤盐分动态及适宜控盐埋深

浅地下水埋深诱发的土壤次生盐碱化是干旱灌区面临的重要生态环境问题。为探讨河套灌区根系层-深层土壤盐分动态及适宜控盐埋深,该研究基于内蒙古河套灌区隆胜研究区68块灌溉农田连续2 a生育期初和生育期末0～1.80 m的土壤盐分、地下水埋深、地下水盐分的监测和作物种植类型的调查,分析了根系层-深层土壤盐分时空动态、季节性平衡机制、多个因素（如气象条件、地下水埋深、地下水矿化度、作物类型和生育期初土壤盐分等）间相互作用对生育期土壤盐分变化的影响,探明了土壤盐分对地下水年际和季节性埋深的响应。结果表明,根系层土壤盐分均在生育期积盐,休耕期脱盐;深层土壤盐分均在生育期脱盐,休耕期积盐。作物类型、生育期初地下水埋深、生育期地下水埋深、地下水盐分及生育期初根系层土壤盐分均对生育期根系层土壤盐分变化有显著影响（P<0.05）。地下水状况与其他各因素的相互作用对生育期根系层土壤盐分变化的影响与水文年型有密切的关系。生育期初根系层土壤盐分随着地下水埋深的增大而指数减小,土壤盐分小于均值的取样点地下水埋深不小于1.60 m。当年均地下水埋深小于2.50 m,不同土层的盐分值和盐分的降低速率随地下水埋深的增加而降低。在地下水埋深小于2.50 m的条件下,以概率分布法得出根系层土壤盐分中位数对应的年均适宜临界控盐地下水埋深为1.77 m,土壤盐分远大于中位数或均值的取样点地下水埋深均小于该埋深。因此,从控盐角度考虑,建议该研究区地下水埋深生育期初应不小于1.60 m,年均地下水埋深应不小于1.77 m。研究结果可为河套灌区通过灌溉制度的设计和排水措施的合理布局控制地下水埋深提供理论依据。     

三种观赏植物对Cd污染土壤酶活性的影响

通过盆栽实验,系统研究了含羞草、白雪姬和树马齿苋对Cd污染土壤中土壤酶的修复作用。结果表明,脲酶、过氧化氢酶和磷酸酶的活性随着Cd浓度的上升不断下降,且均与Cd浓度呈显著负相关关系。3种观赏植物生长均能提高Cd污染土壤中脲酶、磷酸酶和过氧化氢酶的活性。白雪姬还能显著提高土壤蔗糖酶的活性。含羞草、白雪姬和树马齿苋对土壤酶的修复效果均表现为:脲酶>磷酸酶>过氧化氢酶>蔗糖酶,且白雪姬对土壤酶的修复效果显著高于其它两种观赏植物,说明白雪姬作为一种常见的观赏植物,在修复重金属Cd污染土壤方面具有很高的应用前景。     

污染土壤修复技术研究进展

土壤是人类生产活动的重要物质基础,随着社会经济的高速发展和高强度的人类活动,土壤受污染面积不断扩大,土壤质量持续恶化,影响到实现可持续发展的战略目标。由土壤污染导致的农产品的生态安全问题已不容忽视。因此,开展污染土壤修复活动,完善土壤修复技术体系,对阻断污染物进入食物链,防止对人体健康造成危害,实现社会经济可持续发展是非常重要的。该文系统介绍了目前国内外污染场地修复中广泛使用的物理修复技术、化学修复技术、生物修复技术(包括植物修复、微生物修复和动物修复技术)以及相关技术结合使用的联合修复技术,并对各种方法的研究进展进行了较全面的综述,最后也对未来土壤污染修复技术的发展方向进行了展望。     

伊朗中部伊斯法罕地区土地利用对石灰性土壤磁性质和重金属的空间分布的影响

Anthropogenic activities have caused the accumulation of heavy metals in the soil environment. Pollution of the soils significantly reduces environmental quality and affects human health. In many recent studies, magnetic susceptibility measurements have been used for pollution monitoring. The objective of this research was to determine the spatial variability of magnetic properties and selected heavy metals and the effects of land use on their variability in the surface soils of the Isfahan region, Central Iran. A total of 158 composite surface (0-5 cm) samples of calcareous soils were collected from an area of about 700 km2, located along a cross-border transect from Isfahan City to a steel plant, covering urban, industrial, agricultural and uncultivated land uses. Concentrations of copper (Cu), zinc (Zn), lead (Pb), manganese (Mn), iron (Fe), nickel (Ni), chromium (Cr), and cobalt (Co) and magnetic parameters, magnetic susceptibility at low frequency (χlf), natural remanent magnetization (NRM), saturation isothermal remanent magnetization (SIRM), and isothermal remanent magnetization at the field of 100 mT (IRM100mT) and the backfield of 100 mT (IRM-100mT), were measured in all the soil samples. Results showed that magnetic susceptibility in the urban and industrial land topsoils (0--5 cm) samples was significantly higher than that in the agricultural and uncultivated land soils in the study area. Concentrations of Cu, Zn, Pb, Mn, and Fe were positively correlated with magnetic properties (χlf, IRM100mT, SIRM, IRM-100mT, and NRM), which could be attributed to their inputs from traffic emissions and industrial activities at the study sites. Ni and Cr concentrations showed significant negative correlations with magnetic properties. No significant correlation was found between Co concentration and magnetic parameters. The Tomlinson pollution load index (PLI) showed significant correlation with the magnetic properties (χlf, IRM100mT, SIRM, IRM-100mT, and NRM). The spatial distribution of the selected heavy metals and χlf in the study area suggested that activities at the urban and industrial land sites caused greater pollution as compared to that at the study sites of other land uses. The concentrations of Cu and Zn seemed to have been affected by anthropogenic sources, whereas Ni, Cr, and Co were mainly controlled by natural sources in the study area. Moreover, the concentrations of soil Pb and Fe in the study area could be affected by both lithologic and anthropogenic sources. The magnetic parameters appeared to be a proxy measure for the degree of heavy metal contamination and could be a potential method for the detection and mapping of contaminated soils.     

评估土壤微量元素生物有效性测定方法

Trace element-contaminated soils (TECSs) are one of the consequences of the past industrial development worldwide.Excessive exposure to trace elements (TEs) represents a permanent threat to ecosystems and humans worldwide owing to the capacity of metal(loid)s to cross the cell membranes of living organisms and of human epithelia,and their interference with cell metabolism.Quantification of TE bioavailability in soils is complicated due to the polyphasic and reactive nature of soil constituents.To unravel critical factors controlling soil TE bioavailability and to quantify the ecological toxicity of TECSs,TEs are pivotal for evaluating excessive exposure or deficiencies and controlling the ecological risks.While current knowledge on TE bioavailability and related cumulative consequences is growing,the lack of an integrated use of this concept still hinders its utilization for a more holistic view of ecosystem vulnerability and risks for human health.Bioavailability is not generally included in models for decision making in the appraisal of TECS remediation options.In this review we describe the methods for determining the TE bioavailability and technological developments,gaps in current knowledge,and research needed to better understand how TE bioavailability can be controlled by sustainable TECS management altering key chemical properties,which would allow policy decisions for environmental protection and risk management.