Changes in soil organic carbon storage under grassland as evidenced by changes in sulphur input-output budgets

Information about temporal changes in soil organic carbon (C) pools may be obtained indirectly from changes in input-output budgets of organically combined nutrients such as sulphur (S). Sulphur budgets were therefore evaluated for Northern Ireland (NI) for the period 1940-1990, inclusive. These budgets indicated that the land or soil had acted first as a sink but then as a source for S, and that reserves of soil S built up between 1940 and 1965 were totally depleted by the mid-1980s. Pooled data from six long-term soil-monitoring sites on undisturbed grassland suggested that negative S budgets from the late-1970s onwards had been due to the net mineralization of soil organic matter and thus were indicative of net losses of organic C from surface soil horizons. There was some evidence that the decline in rainfall and fertiliser S inputs from the mid-1960s may have precipitated the breakdown of soil organic matter.     

Accumulation of lead, zinc, copper and cadmium by 12 wetland plant species thriving in metal-contaminated sites in China

The concentrations of lead, zinc, copper and cadmium accumulated by 12 emergent-rooted wetland plant species including different populations of Leersia hexandra, Juncus effusus and Equisetum ramosisti were investigated in field conditions of China. The results showed that metal accumulation by wetland plants differed among species, populations and tissues. Populations grown in substrata with elevated metals contained significantly higher metals in plants. Metals accumulated by wetland plants were mostly distributed in root tissues, suggesting that an exclusion strategy for metal tolerance widely exists in them. That some species/populations could accumulate relatively high metal concentrations (far above the toxic concentration to plants) in their shoots indicates that internal detoxification metal tolerance mechanism(s) are also included. The factors affecting metal accumulation by wetland plants include metal concentrations, pH, and nutrient status in substrata. Mostly concentrations of Pb and Cu in both aboveground and underground tissues of the plants were significantly positively related to their total and/or DTPA-extractable fractions in substrata while negatively to soil N and P, respectively. The potential use of these wetland plants in phytoremediation is also discussed.     

苯胺废水处理技术研究进展

综述了有毒、难生物降解废水———苯胺废水的各种处理技术及基本原理 ,这些处理技术主要包括物理、化学、生物等方法     

USSB反应器预处理聚酯生产废水

采用上流式分段污泥床（upflow staged sludge bed）反应器对聚酯废水进行了预处理试验研究.反应器内厌氧污泥经过近70 d的培养驯化后,用于处理聚酯废水.当进水COD值为800～2000 mg/L,HRT约为16～20 h时,其COD去除率基本能稳定在50%～55%之间;聚酯废水经预处理后,其BOD5/COD值由原来的0.3左右提高到约为0.6,取得了较好的预处理效果.但系统的总产气量由培养期的约13 L/d降至0.8 L/d左右,其中甲烷气体的含量也由50%下降至约6%.     

Concurrent catalytic removal of typical volatile organic compound mixtures over Au-Pd/α-MnO2 nanotubes

α-MnO_2 nanotubes and their supported Au-Pd alloy nanocatalysts were prepared using hydrothermal and polyvinyl alcohol-protected reduction methods, respectively. Their catalytic activity for the oxidation of toluene/m-xylene, acetone/ethyl acetate, acetone/m-xylene and ethyl acetate/m-xylene mixtures was evaluated. It was found that the interaction between Au-Pd alloy nanoparticles and α-MnO_2 nanotubes significantly improved the reactivity of lattice oxygen, and the 0.91 wt.% Au0.48 Pd/α-MnO_2 nanotube catalyst outperformed the α-MnO_2 nanotube catalyst in the oxidation of toluene, m-xylene, ethyl acetate and acetone. Over the0.91 wt.% Au0.48 Pd/α-MnO_2 nanotube catalyst,(i) toluene oxidation was greatly inhibited in the toluene/m-xylene mixture, while m-xylene oxidation was not influenced;(ii) acetone and ethyl acetate oxidation suffered a minor impact in the acetone/ethyl acetate mixture; and(iii) m-xylene oxidation was enhanced whereas the oxidation of the oxygenated VOCs(volatile organic compounds) was suppressed in the acetone/m-xylene or ethyl acetate/m-xylene mixtures. The competitive adsorption of these typical VOCs on the catalyst surface induced an inhibitive effect on their oxidation, and increasing the temperature favored the oxidation of the VOCs. The mixed VOCs could be completely oxidized into CO_2 and H_2 O below 320°C at a space velocity of 40,000 m L/(g·hr). The 0.91 wt.% Au0.48 Pd/α-MnO_2 nanotube catalyst exhibited high catalytic stability as well as good tolerance to water vapor and CO_2 in the oxidation of the VOC mixtures. Thus, the α-MnO_2 nanotube-supported noble metal alloy catalysts hold promise for the efficient elimination of VOC mixtures.     

北京市加油站职业病危害现状调查

目的:了解北京地区加油站职业病危害现状。方法:按照国家相关标准规范对北京市137家加油站的工作场所进行了汽油、苯、甲苯、二甲苯和噪声的检测。结果:加油站职业病危害因素浓/强度均符合国家职业接触限值要求,确定汽油为主要职业病危害因素。结论:北京市加油站职业危害较小,但长期接触低浓度的汽油,加之劳动强度大、作业时间长等特点会损害人体的免疫功能。     

Selective sorption of perfluorooctane sulfonate on molecularly imprinted polymer adsorbents

Perfluorooctane sulfonate (PFOS), as a potential persistent organic pollutant, has been widely detected in water environments, and has become a great concern in recent years. PFOS is very stable and difficult to decompose using conventional techniques. Sorption may be an attractive method to remove it from water. In this study, the molecularly imprinted polymer (MIP) adsorbents were prepared through the polymerization of 4-vinylpyridine under different preparation conditions in order to remove perfluorooctane sulfonate (PFOS) from water. The MIP adsorbents using perfluorooctanoic acid (PFOA) as the template had good imprinting effects and could selectively remove PFOS from aqueous solution. The sorption behaviors including sorption kinetics, isotherms, and effect of pH, salt, and competitive anions were investigated. Experimental results showed that the sorption of PFOS on the MIP adsorbents was very fast, pH-dependent, and highly selective. The achieved fast sorption equilibrium within 1 h was attributed to the surface sorption on the fine adsorbents. The sorption isotherms showed that the sorption selectivity of PFOS on the MIP adsorbents decreased at high PFOS concentrations, which may be due to the double-layer sorption and the formation of PFOS micelles on the sorbent surface. The sorption of PFOS on the MIP adsorbents was mainly dominated by the electrostatic interaction between the protonated vinylpyridine on the adsorbent surface and the anionic PFOS. The prepared MIP adsorbents can potentially be applied in water and wastewater treatment for selective removal of PFOS.     

高铁酸钾处理废水中硝基苯的研究

本实验以高铁酸钾为水处理剂,对其在废水中的硝基苯的去除进行了研究,考察了高铁酸钾的用量、pH值、反应时间及硝基苯的初始浓度四个影响因素对硝基苯去除率的影响,最终确定了高铁酸钾去除硝基苯的最佳反应条件为：初始pH值为9,高铁酸钾与硝基苯的摩尔比为10：1,反应时间30min,初始浓度小于254．5mg/L时,硝基苯的去除率最佳,达到到6．2％。     

污染源在线监控设施市场化运营之思考

社会化运营是污染源在线监控系统发挥应用价值的基础,国内在线监控设施社会化运营以市场化运营、统一运营和特许经营三种模式为主流,比较三种模式的优势和劣势,形成的结论是大部分城市因缺少相对宽松的政策环境,只能选择市场化运营模式。结合南京市管理实践,着重分析污染源在线监控设施市场化运营所面临的问题,提出了解决设想。     

徒骇河沉积物和沿岸土壤对磷酸盐的吸附动力研究

通过实验模拟的方法,研究了徒骇河沉积物和沿岸土壤对磷酸盐的吸附作用,发现二者均具有较强的对磷酸盐的吸附作用,沉积物的吸附作用强于土壤,沉积物在2h内即可达到吸附平衡,土壤在12h内达到平衡;在中等扰动条件下,随着磷酸盐浓度的上升,沉积物和土壤的磷酸盐吸附容量均明显增加,沉积物的吸附容量大于土壤,这种吸附能力对徒骇河水体的磷酸盐缓冲作用起着积极的作用;徒骇河沉积物和沿岸土壤对磷酸盐的吸附等温曲线符合Langmuir等温吸附方程。