硝酸钙添加和锆改性膨润土覆盖联用控制底泥中磷释放的效果及机制

通过底泥培养实验,研究了硝酸钙添加和锆改性膨润土覆盖联用控制底泥中磷释放的效果及机制.结果发现,在缺氧条件下,底泥中磷会先释放出来进入间隙水中,而后穿越底泥-水界面扩散进入上覆水中,导致上覆水中溶解态活性磷(SRP)和薄膜扩散梯度(DGT)有效态磷浓度较高.但是,联合使用硝酸钙添加和锆改性膨润土覆盖可有效控制底泥中磷释...     

Individual and combined toxic effects of cypermethrin and chlorpyrifos on earthworm

Toxicities were assessed for a pyrethroid (cypermethrin) and an organophosphate insecticide (chlorpyrifos) individually and in combination. A series of tests were conducted on di erent responses (acute, chronic, behavioral) of earthworms of species Eisenia fetida andrei in the ecological risk assessment of these pesticides. The results showed that the toxicity of the mixture of cypermethrin and chlorpyrifos was significantly higher than either of these pesticides individually, especially on the earthworm’s chronic responses. At a concentration of 5 mg/kg, the mixture caused significant reductions on the growth and reproduction rates of earthworms, but did not cause any significant e ect when the individual was tested. The increase in toxicity of the pesticide mixture means that the use of toxicity data obtained exclusively from single-pesticide experiments may underestimate the ecological risk of pesticides that actually present in the field.     

苯酚、菲在BS-12/DTAB复配修饰膨润土上吸附的差异

为了探究复配修饰膨润土吸附疏水性不同的污染物的差异,采用阳离子型表面修饰剂十二烷基三甲基溴化铵(DTAB)对两性表面修饰剂十二烷基二甲基甜菜碱(BS-12)修饰膨润土进行复配修饰,采用批处理法研究复配修饰膨润土总修饰比例对苯酚和菲的等温吸附影响,并对比不同温度、pH值和离子强度条件下供试土样对苯酚和菲吸附量、热力学参数的差异.结果表明:随着总修饰比例的增大,复配修饰膨润土对苯酚及菲的吸附能力逐渐增强,0~50%CEC修饰比例下,菲的吸附率大于苯酚的吸附率,当修饰比例超出50%CEC后,苯酚的吸附率大于菲的吸附率,总修饰比例超出150%CEC后,膨润土对苯酚的吸附率变化趋于平缓,而对菲的吸附率开始呈下降趋势;随着土样总修饰比例的增大,温度对苯酚及菲吸附量的抑制效果降低;在KNO_3浓度为0.001~0.1 mol·L~(-1)时,苯酚及菲的吸附量均随着KNO_3浓度的增大而增大;随着pH值的升高,苯酚的吸附量逐渐增大,在pH=7处达到最大,而菲的吸附量则始终呈降低趋势.热力学参数显示,随着总修饰比例的增大,复配修饰土样对苯酚和菲的吸附自发性增强,混乱度增大,当总修饰比例超出150%CEC后,自发性减弱,混乱度下降.     

Phytotoxicity assessment of phenanthrene, pyrene and their mixtures by a soil-based seedling emergence test

Seedling emergence tests were conducted in a meadow brown soil using five plant species ( i. e., Chinese cabbage, green onion, tomato, turnip and wheat) to determine the phytotoxicity of phenanthrene, pyrene and their mixtures. The soil was amended with up to 1000mg/kg soil of phenanthrene or 600 mg/kg soil of pyrene. Seedling emergence and root growth were measured. The results indicated that root elongation was more sensitive than seedling emergence. Root length decreased with increasing phenanthrene or pyrene concentrations(p≤0.05). Phenanthrene was more phytotoxic than pyrene. The lowest observable adverse effect concentration(LOAEC) was 10mg/kg for phenanthrene when tested with green onion, and 50mg/kg for pyrene when tested with wheat. Among the five species, wheat was found to be the most sensitive. When amended jointly at or below their respective LOAEC, phenanthrene and pyrene produced a synergistic toxic effect.     

Distribution characteristics of ammonia-oxidizing bacteria in the Typha latifolia constructed wetlands using fluorescent in situ hybridization(FISH)

A molecular biology method, fluorescent in situ hybridization（FISH）, in which the pre-treatment was improved in allusion to the media of the constructed wetlands（CW）, e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria（AOB） quantity and the relation with oxidation-reduction potential（ORP） in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.     

城市高污染水体生物生态处理技术研究

针对城市高污染水体的特点,建成了粉煤灰基质滤料生物过滤与复合水生植物滤床组合处理系统。生物过滤在有机物和氨氮的去除方面起主要作用,磷则主要是通过人工湿地去除。运行结果表明,组合工艺出水COD、TP、NH3-N、TN平均浓度分别为16.35 mg/L、0.08 mg/L、2.68 mg/L、15.63 mg/L,均满足《城市污水再生利用——城市杂用水水质》(GB/T18920-2002)标准要求。     

几种农药在烟草上的消解动态与复合效应

采用室外盆栽试验方法,研究了吡虫啉、高效氯氰菊酯在烟草上的消解动态,同时研究了多菌灵、高效氯氰菊酯对吡虫啉及吡虫啉对高效氯氰菊酯降解速度的影响.结果表明,吡虫啉在烟叶中的消解半衰期为3.98d,喷药后15d,降解了94.60%;高效氯氰菊酯对吡虫啉降解表现出延缓作用,而多菌灵对吡虫啉降解表现出加速作用.高效氯氰菊酯在烟草中消解半衰期为4.82d,喷药后15d,消解了88.32%;吡虫啉对高效氯氰菊酯的消解表现出延缓作用.     

硫脲改性猪粪生物质炭对模拟农田径流中镉和草甘膦吸附特征

为同时去除农田地表径流中的重金属和农药,利用猪粪制备未改性猪粪生物质炭（简称"未改性生物质炭"）和硫脲改性猪粪生物质炭（简称"改性生物质炭"）,分析比较硫脲改性对生物质炭的pH、元素组成、表面含氧官能团和巯基含量等理化性质的影响,并系统地研究了单一和复合污染体系中初始浓度对两种生物质炭吸附水溶液中镉（Cd）和草甘膦效率的影响.结果表明:①与未改性生物质炭相比,改性生物质炭的pH、O/C（原子比）和H/C（原子比）降低,比表面积增大,含氧官能团和巯基含量增加.②与未改性生物质炭相比,改性生物质炭对Cd和草甘膦的吸附能力增强,最大表观吸附量（Q_max）增加了近3倍;随着Cd和草甘膦初始浓度的增加,未改性和改性生物质炭对Cd和草甘膦的吸附量逐渐增加,增加量最高分别达18.52%和7.60%.③单一污染体系中两种生物质炭对Cd或草甘膦的吸附更符合Langmuir等温吸附模型,说明其对Cd或草甘膦的吸附机理是单分子层的吸附起主导作用.④复合污染体系中,未改性和改性生物质炭对Cd的吸附能力分别增加了25.28%和21.26%,未改性生物质炭对Cd的最大表观吸附量增加了29.34%,但改性生物质炭对Cd的最大表观吸附量降低了47.28%;未改性和改性生物质炭对草甘膦的吸附能力减弱,但最大表观吸附量分别增加了2.63和3.45倍.研究显示,硫脲改性猪粪生物质炭作为一项有前景的新技术,为解决实际环境中的复合污染问题提供了经济环保的技术手段.      

紫外线与消毒剂联合作用于黄浦江源水的研究

针对黄浦江源水砂滤出水,进行了紫外线单独作用的研究,同时对于紫外线与消毒剂联合消毒时消毒剂的投加方式对灭菌作用和消毒副产物的影响进行了研究。实验结果表明:当紫外线剂量达到42 mJ/cm2时出水水质已达到了生活饮用水卫生标准中对细菌总数和大肠杆菌数的要求,且在相同紫外剂量下,高强度时对细菌的灭活效果要好于低强度时的效果;先紫外消毒后消毒剂消毒对于微生物具有很好的杀灭作用,但是不能减少消毒副产物的产生;紫外线和消毒剂同时作用对于微生物的杀灭作用不佳,但是出水的消毒剂余量高,消毒副产物量少,这样有利于出水的安全稳定性;先消毒剂消毒再紫外消毒,发现对于消毒副产物没有多大的降解作用,更浪费了高的紫外剂量。     

土壤铜、 铬(Ⅵ)复合污染重金属形态转化及其对生物有效性的影响

通过盆栽试验和室内化学分析相结合的方法,研究了外源铜、铬（Ⅵ）单一和复合污染中土壤金属形态转化及其对生物有效性的影响.结果表明,外源铜、铬（Ⅵ）单一污染土壤中,铬主要以残渣态和有机结合态形式存在,而铜则主要以铁锰氧化物结合态和残渣态形式存在.铜、铬（Ⅵ）复合污染时,低浓度铜（≤400 mg.kg-1）促进铬向交换态转化...