Dissipation of polycyclic aromatic hydrocarbons and microbial activity in a field soil planted with perennial ryegrass

Dissipation and plant uptake of polycyclic aromatic hydrocarbons (PAHs) in contaminated agricultural soil planted with perennial ryegrass were investigated in a field experiment. After two seasons of grass cultivation the mean concentration of 12 PAHs in soil decreased by 23.4% compared with the initial soil. The 3-, 4-, 5-, and 6-ring PAHs were dissipated by 30.9%, 25.5%, 21.2%, and 16.3% from the soil, respectively. Ryegrass shoots accumulated about 280 μg·kg^-1, shoot dry matter biomass reached 2.48 × 10⁴ kg·ha^-1, and plant uptake accounted for about 0.99% of the decrease in PAHs in the soil. Significantly higher soil enzyme activities and microbial community functional diversity were observed in planted soil than that in the unplanted control. The results suggest that planting ryegrass may promote the dissipation of PAHs in long-term contaminated agricultural soil, and plant-promoted microbial degradation may be a main mechanism of phytoremediation.     

日本民间强震观测的利与弊

近几年,日本许多机关都在公开地震观测数据,尤其是强震数据。除通过K—NET公开数据的防灾科学技术研究所和日本气象协会外,震灾预防悱会、建筑学会、关西地震观测研究协会以及10个电力共同研究等民间机构电都致力于此项研究。强震观测数据内容以自由地丛表面的为多。从抗震上程学和地震防灾角度来看,所哺的垂直台阵地震观测数据在增加,反映出人们对地基上地震波增幅的重要性队激的提高.但有荧建筑物的观测数据．除日本建筑学会根据兵库县南部地震进行收集、     

Size fractionation and characterization of nanocolloidal particles in soils

A protocol was developed to fractionate soil particles down to the nanocolloid scale by combining sieving, sedimentation, centrifugation, and cross-flow filtration (CFF). The validity of the method and the performance of the CFF system were tested by characterizing fractions using laser granulometry, electron microscopy, and chemical analysis. The 0.1-μm-pore-size membrane CFF system effectively retained nanocolloids (<0.1 μm) as shown by laser granulometry and observed directly by transmission electron microscopy. However, environmental scanning electron microscopy images of freeze-dried colloids were very different from their TEM counterparts, suggesting that sample preparation influenced microscopy imaging. Chemical analysis of Cu, Cd, and organic carbon in each fraction showed that the concentrations of these components increased as particle size decreased, indicating colloids and nanocolloids play an important role in retaining trace metals. Particle-size fractionation combined with chemical analysis and electron microscopy can provide insight into the nature and properties of nanocolloids in soil.     

城市生活垃圾有机组分厌氧发酵产氢和甲烷

为了提高能源回收效率,采用大米、土豆、生菜、瘦肉、花生油和榕树叶作为实验原料,模拟有机垃圾中普遍存在的淀粉、膳食纤维、蛋白质、脂肪和木质纤维类成分,进行厌氧发酵产氢以及对其剩余物厌氧发酵产甲烷.结果表明.在厌氧发酵产氢阶段,整个过程没有甲烷生成,大米、土豆、生菜、瘦肉、花生油和榕树叶的氢气产率分别为125、103、35、0、5和0 mL g-1(VS),能源回收效率分别为7.9%、6.8%、1.9%、0、0.1%和0.大米、土豆和生菜的氢气浓度分别为34%～59%、41%～56%和37%～70%,整个产氢阶段没有甲烷生成.在厌氧发酵产甲烷阶段,上述原料的甲烷产率分别为232、237、148、278、866和50 mL g-1(VS),生物气中甲烷含量分别为42%～70%、57%～71%、73%～77%、59%～73%、68%～80%和54%～74%.厌氧发酵联产氢气和甲烷整个过程上述原料的能源回收效率分别为56.3%、58.4%、28.8%、39.2%、81.2%和8.8%,总COD去除率分别为72.30%、81.70%、32.63%、47.59%、97.46%和11.29%.图4表5参35     

酸雨对长江三角洲地区四种典型土壤中锌解吸的影响

近年来酸雨危害频繁发生,特别是长江三角洲地区,酸雨致使土壤中重金属锌的吸附和解吸发生了一定的变化。选取具有代表性的长江三角洲地区4种典型土壤,通过加入外源重金属锌培育污染土样,在不同pH的酸雨下对已污染土样进行解吸。通过实验探究土壤母质对于重金属锌的吸附及解吸的特点,为国家制定土壤标准提供可靠的数据支持。结果表明：土壤中锌的解吸量随着pH的降低而增加;比较不同母质发育而成的土壤,在pH=4.0、5.6模拟已污染土壤中锌的解吸量顺序为：沟沟堆积母质〉湖相沉积物母质〉河相沉积物母质〉海相沉积物母质。在pH=2.0、3.0时,河相沉积物母质、湖相沉积物母质解吸量迅速增加,超过海相沉积物母质锌的解吸量。     

铜、镉及其交互作用对泡泡草细胞超微结构的影响

为了解铜、镉对泡泡草根、茎、叶细胞亚显微结构的毒害及作用位点 ,以期为进一步研究鸭跖草属植物的耐重金属机理提供理论基础 ,本文通过透射电子显微技术研究了 75 μmol·L-1铜和 5 0 μmol·L-1镉及其交互污染对泡泡草根、茎、叶细胞超微结构的影响和铜、镉在细胞中的分布 .结果表明 :75 μmol·L-1铜和 5 0 μmol·L-1镉均对泡泡草根细胞造成明显损伤 .铜使根细胞产生质壁分离、细胞质浓缩、部分细胞空泡化 ,使线粒体脊突消失、结构模糊、外膜破坏 ;镉使根细胞空泡化 ,并在部分空泡化的细胞里产生大小不等的颗粒状物 ;铜、镉交互污染使根细胞受害程度加深 ,并兼有两者的受害症状特征 :线粒体结构彻底破坏、空泡化细胞里的颗粒物更大电子密度更高、质壁分离现象更普遍、质膜上的颗粒物沉淀更大 .铜、镉及其交互污染使泡泡草茎细胞产生质壁分离 ,对叶细胞无明显伤害 .所以铜、镉及其交互作用在试验浓度下 ,对泡泡草各器官的损伤程度为根 >茎 >叶 .     

武夷山自然保护区常绿阔叶林优势种对土壤呼吸的影响

为揭示森林土壤呼吸异质性的影响因素,以武夷山自然保护区常绿阔叶林优势种甜槠(Castanopsis eyrei)、细叶青冈(Cyclobalanopsis tenuifolia)、米槠(Castanopsis carlesii)为研究对象,采用LI-8100碳通量系统测定土壤呼吸速率及其影响因子土壤温度、土壤含水量值,...     

Diphenylarsinic acid sorption mechanisms in soils using batch experiments and EXAFS spectroscopy

• DPAA sorption data was found to fit the Freundlich equation. • K_f was significantly positive correlated with oxalate-extractable Fe₂O₃. • Ligand exchange was the main mechanism for DPAA sorption on soils. • Bidentate binuclear and monodentate mononuclear DPAA bonds were identified. Diphenylarsinic acid (DPAA) is a phenyl arsenic compound derived from chemical warfare weapons. Macroscopic and microscopic work on DPAA sorption will provide useful information in predicting the partitioning and mobility of DPAA in the soil-water environment. Here, batch experiments and extended X-ray absorption fine structure (EXAFS) spectroscopy were used to investigate the sorption mechanisms of DPAA. The DPAA sorption data from 11 soil types was found to fit the Freundlich equation, and the sorption capacity, K_f, was significantly and positively correlated with oxalate-extractable Fe₂O₃. The K_f values of eight of the 11 untreated soils (1.51–113.04) significantly decreased upon removal of amorphous metal (hydr)oxides (0.51–13.37). When both amorphous and crystalline metal (hydr)oxides were removed from the untreated soils, the K_f values either decreased or slightly increased (0.65–3.09). Subsequent removal of soil organic matter from these amorphous and crystalline metal (hydr)oxide-depleted samples led to further decreases in K_f to 0.02–1.38, with only one exception (Sulfic Aquic-Orthic Halosols). These findings strongly suggest that ligand exchange reactions with amorphous metal (hydr)oxides contribute most to DPAA sorption on soils. EXAFS data provide further evidence that DPAA primarily formed bidentate binuclear (²C) and monodentate mononuclear (¹V) coring-sharing complexes with As-Fe distances of 3.34 and 3.66 Å, respectively, on Fe (hydr)oxides. Comparison of these results with earlier studies suggests that ²C and ¹V complexes of DPAA may be favored under low and high surface coverages, respectively, with the formation of ¹V bonds possibly conserving the sorption sites or decreasing the steric hindrance derived from phenyl substituents.     

微污染水源水生物处理工艺中IAL-CHS与三相流化床的初步比较

初步比较气升式内循环蜂窝陶瓷反应器(IAL-CHS)和内循环三相流化床反应器(ITFB)对微污染水源水进行生物预处理的效果。IAL-CHS反应器比ITFB反应器挂膜启动速度快,但是在挂膜期承受冲击负荷能力较ITFB反应器差。在进水相同条件下,两者所能达到的最小水力停留时间、最大体积负荷和容积负荷相差不大,但是ITFB反应器的曝气强度却为IAL-CHS反应器的3.33倍,并且比IAL-CHS反应器出水SS高,浊度去除率低,单位载体的生物量及活性生物量小。     

Accumulation levels and characteristics of some pesticides in human adipose tissue samples from Southeast China

This paper presents a comprehensive study of pesticide levels and bio-accumulation characteristics in human adipose tissues among residents of Southeast China. A large number of adipose samples (n = 633) were selected for 58 pesticides and were analyzed by high sensitive Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS). The results showed that POPs pesticides were frequently detected, including 2,4′-DDD, 2,4′-DDE, 2,4′-DDT, 4,4′-DDD, 4,4′-DDE, 4,4′-DDT, α-HCH, β-HCH, γ-HCH, δ-HCH, hexachlorobenzene (HCB), and mirex. Other detected pesticide species were dicofol, methamidophos and chlordimeform, which have rarely been reported. Comparing to different countries, the concentrations of total DDT and HCH in these three Chinese southeastern sites were in the middle range, whereas the HCB and mirex were in the lower end. A significant correlation was observed between region as well as age and POPs pesticide levels. Some pesticide residue levels were also found significantly correlated to occupation. However, there was no significant correlation between gender and pesticides. Meanwhile, it is interesting to find that mortality of malignant tumors tends to associate with the pesticides levels in human adipose tissue. More importantly, the measured data presented in this study provide realistic information which is useful for assessing human exposure to pesticides in the general population of Southeast China.