Fuel particles in the Chernobyl cooling pond: current state and prediction for remediation options

During the coming years, a management and remediation strategy for the Chernobyl cooling pond (CP) will be implemented. Remediation options include a controlled reduction in surface water level of the cooling pond and stabilisation of exposed sediments. In terrestrial soils, fuel particles deposited during the Chernobyl accident have now almost completely disintegrated. However, in the CP sediments the majority of ⁹⁰Sr activity is still in the form of fuel particles. Due to the low dissolved oxygen concentration and high pH, dissolution of fuel particles in the CP sediments is significantly slower than in soils. After the planned cessation of water pumping from the Pripyat River to the Pond, significant areas of sediments will be drained and exposed to the air. This will significantly enhance the dissolution rate and, correspondingly, the mobility and bioavailability of radionuclides will increase with time. The rate of acidification of exposed bottom sediments was predicted on the basis of acidification of similar soils after liming. Using empirical equations relating the fuel particle dissolution rate to soil and sediment pH allowed prediction of fuel particle dissolution and ⁹⁰Sr mobilisation for different remediation scenarios. It is shown that in exposed sediments, fuel particles will be almost completely dissolved in 15–25 years, while in parts of the cooling pond which remain flooded, fuel particle dissolution will take about a century.     

Influence of papermill sludge on growth of Medicago sativa, Festuca rubra and Agropyron trachycaulum in gold mine tailings: a greenhouse study

A greenhouse study was undertaken to determine the suitability of adding papermill sludge to neutral/alkaline gold mine tailings to improve the establishment of Festuca rubra, Agropyron trachycaulum and Medicago sativa. Festuca rubra root and shoot biomass and A. Trachycaulum shoot biomass were increased with papermill sludge amendment. The addition of papermill sludge and fertilizer drastically increased the shoot and root biomass of M. sativa (20-30 times) while A. trachycaulum and F. rubra showed a more moderate increase in growth. Photosynthetic pigment content of the leaves was higher in papermill sludge treatments than in the treatments without papermill sludge. The organic carbon content, macro-aggregate content and field capacity of the gold mine tailings were increased while the bulk density was decreased by the addition of papermill sludge. This study suggests that addition of papermill sludge and adequate fertilization can alleviate some of the adverse conditions of neutral/alkaline gold mine tailings.     

Heavy metal distribution and chemical speciation in tailings and soils around a Pb-Zn mine in Spain

Soil pollution by lead, zinc, cadmium and copper was characterized in the mine tailings and surrounding soils (arable and pasture lands) of an old Spanish Pb-Zn mine. Sixty soil samples were analyzed, determining the total metal concentration by acid digestion and the chemical fractionation of Pb and Zn by the modified BCR sequential extraction method. Samples belonging to mine waste areas showed the highest values, with mean concentrations of 28,453.50 mg kg(-1) for Pb, 7000.44 mg kg(-1) for Zn, 20.57 mg kg(-1) for Cd and 308.48 mg kg(-1) for Cu. High concentrations of Pb, Zn and Cd were found in many of the samples taken from surrounding arable and pasture lands, indicating a certain extent of spreading of heavy metal pollution. Acidic drainage and wind transport of dust were proposed as the main effects causing the dispersion of pollution. Sequential extraction showed that most of the Pb was associated with non-residual fractions, mainly in reducible form, in all the collected samples. Zn appeared mainly associated with the acid-extractable form in mine tailing samples, while the residual form was the predominant one in samples belonging to surrounding areas. Comparison of our results with several criteria reported in the literature for risk assessment in soils polluted by heavy metals showed the need to treat the mine tailings dumped in the mine area.     

某电厂灰渣库整体稳定性探讨

从物理力学参数的选取方面对某电厂灰渣库一期工程1号副坝的整体稳定性进行探讨,从中发现原有研究结果的偏差,并对坝体的整体稳定性作出了比较客观的结论,同时也通过对比总应力强度与有效应力强度指标的不同适用范围,提出了在灰渣坝（尾矿坝）的稳定性分析中应对其区别对待,以免出现不必要的错误,从而有效地指导灰渣库（尾矿库）的安全管理工作。     

铜陵铜矿尾矿理化性质的变化对植被重建的影响

通过野外调查和室内分析,对铜陵不同弃置堆放时间的铜矿尾矿的理化性质及植被定居状况进行了研究。结果表明,随着堆放时间的推移,表层尾矿的稳定性增加,基质结构改善,持水肥能力提高,有机质,全氮、有效磷、速效钾、有效铜及水溶性盐类含量上升,ｐＨ值降低,有的甚至出现酸化现象。铜矿尾矿的植被定居状况与其堆放时间及理化性质的变化有着密切关系。     

铀尾矿库中238U运移数值模拟

铀尾矿库退役后要进行环境治理和长期监测,对库中放射性核素进行模拟可以为放射性废物安全管理提供科学依据.笔者采用有限元法对尾矿中238U在地下水中的迁移情况进行了模拟,结果表明,尾矿库治理后1 000 a,238U迁移到距尾矿库边缘183 m的地方,未到达附近河流.     

氧化塘技术处理采油废水运转效果监测及分析

氧化塘技术是处理工业废水常用的方法之一。对桩西采油厂的氧化塘设置了5个监测点位,每月监测4～8次。由监测数据可知,氧化塘温度决定藻类、细菌和其他水生物优势种属的演替;COD的去除效果受季节影响较小;塘内水流受风向影响较大;对石油类物质的去除效果比较稳定;挥发酚的去除与季节有较大关联;硫化物的去除率很高。分析结果表明,该氧化塘运转状况良好,但应注意来水状况。     

云南省优势矿产尾矿砂捕集及矿化封存CO2潜力分析

为了解云南省尾矿库“两个清单”中保留库的碳减排潜力,使用改进的Steinour方程计算了云南省各州市不同类型尾矿砂的CO₂固定量,根据《IPCC国家温室气体列表指南》中提供的方法计算了云南省2011~2020年碳排放量.结果表明,红河州、玉溪市、昆明市尾矿砂的捕集及矿化封存CO₂的潜力较大,占云南省保留库尾矿砂CO₂矿化封存量的65.79%;铅锌矿、赤泥、锡矿的理论固碳量较高,分别为0.201, 0.173, 0.158t/t,以上3种尾矿砂的固碳量占云南省尾矿砂固碳量的79.45%;若将云南省保留库堆存的尾矿砂全部用于CO₂的矿化封存,可减少2011~2020年间云南省累积碳排放量的2.81%,工业碳累积排放量的3.16%,采矿业碳排放量的12.36%,具有较好的工业应用前景.