赤霉酸暴露对SD大鼠青春期发育的影响

赤霉酸是目前国内外使用极其广泛的一种植物生长调节剂,但是针对其发育毒性的数据依然较少。本文探讨了赤霉酸暴露对SD大鼠青春期发育的影响。参考国内外环境内分泌干扰物危害的评价方法,将144只初断乳SD大鼠按体重随机分为4组,分别为对照组和1、10、100 mg·kg-1bw剂量组,采用经口灌胃方式对雄鼠连续染毒28 d,雌鼠连续染毒21 d。暴露结束后检测大鼠的体重、食物利用率、雄鼠包皮分离时间/雌鼠阴道开口时间、血清生化指标、脏器系数及组织病理学的变化。研究结果表明,与对照组相比,仅10和100 mg·kg-1bw剂量组雄鼠的肌酐水平显著升高(P<0.01),100 mg·kg-1bw剂量组雌鼠谷丙转氨酶水平有显著升高(P<0.01)。而与对照组相比,所有剂量组均未观察到大鼠的体重、食物利用率、雄鼠包皮分离时间/雌鼠阴道开口时间、脏器系数等指标有显著性差异的改变(P>0.05),组织病理学结果亦显示大鼠重要器官无损害性改变。因此,在本试验给予的剂量范围内赤霉酸染毒不会对SD大鼠青春期发育产生显著影响。     

Comparative experiment on treating digested piggery wastewater with a biofilm MBR and conventional MBR: simultaneous removal of nitrogen and antibiotics

A biofilm membrane bioreactor (BF-MBR) and a conventional membrane bioreactor (MBR) were parallelly operated for treating digested piggery wastewater. The removal performance of COD, TN, NH₄ ⁺-N, TP as well as antibiotics were simultaneously studied when the hydraulic retention time (HRT) was gradually shortened from 9 d to 1 d and when the ratio of influent COD to TN was changed. The results showed that the effluent quality in both reactors was poor and unstable at an influent COD/TN ratio of 1.0±0.2. The effluent quality was significantly improved as the influent COD/TN ratio was increased to 2.3±0.5. The averaged removal rates of COD, NH₄ ⁺-N, TN and TP were 92.1%, 97.1%, 35.6% and 54.2%, respectively, in the BF-MBR, significantly higher than the corresponding values of 91.7%, 90.9%, 17.4% and 31.9% in the MBR. Analysis of 11 typical veterinary antibiotics (from the tetracycline, sulfonamide, quinolone, and macrolide families) revealed that the BF-MBR removed more antibiotics than the MBR. Although the antibiotics removal decreased with a shortened HRT, high antibiotics removals of 86.8%, 80.2% and 45.3% were observed in the BF-MBR at HRTof 5–4 d, 3–2 d and 1 d, respectively, while the corresponding values were only 83.8%, 57.0% and 25.5% in the MBR. Moreover, the BF-MBR showed a 15% higher retention rate of antibiotics and consumed 40% less alkalinity than the MBR. Results above suggest that the BF-MBR was more suitable for digested piggery wastewater treatment.

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Effect of tea saponin on phytoremediation of Cd and pyrene in contaminated soils by <Emphasis Type="Italic">Lolium multiflorum</Emphasis>

Tea saponin (TS), a kind of green biosurfactant produced by plants, was added into the Cd–pyrene co-contaminated soils to evaluate its influence on phytoremediation of Cd and pyrene by Lolium multiflorum. The results showed that the accumulation of pyrene in L. multiflorum was significantly promoted by the TS. Compared with no TS treatments (PL and ML), the aboveground concentrations of pyrene in TS treatments (PLT and MLT) increased by 135 and 30%, respectively, and the underground concentrations of pyrene in TS treatments (PLT and MLT) increased by 40 and 25%. The concentrations of Cd in the aboveground and underground parts in single contaminated treatments were all significantly more than those in co-contaminated treatments, while the situation of pyrene was quite the reverse. Besides, the addition of TS enhanced activities of dehydrogenase and polyphenol oxidase in soils and increased the biomass of L. multiflorum. The micromorphology of L. multiflorum was not affected by TS. The study suggests that the use of L. multiflorum with TS is an alternative technology for remediation of Cd–pyrene co-contaminated soils.     

Heavy metal pollution in vegetables grown in the vicinity of a multi-metal mining area in Gejiu,China: total concentrations,speciation analysis,and health risk

A field survey was conducted to investigate the present situation and health risk of arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in soils and vegetables in a multi-metal mining area, Gejiu, China. Furthermore, three vegetables (water spinach, potato, and summer squash) containing high metal concentrations were selected to further analyze metal speciation. The results showed that the average concentrations of five metals in soil exceeded the limiting values, and their bioavailable concentrations were significantly positively correlated to the total ones. Heavy metals in the edible parts of vegetables also exceeded the corresponding standards. The leaves of pakchoi, peppermint, and coriander had a strong metal-accumulative ability and they were not suitable for planting. Except the residue forms, the main forms of metals in the edible parts of three selected vegetables were ethanol-, NaCl-, and HAc-extractable fractions for As, Pb, and Cd, respectively; however, Cu was mainly presented as NaCl-extractable and Zn as HAc-extractable fractions. A high proportion of ethanol-extractable As showed that As bioactivity and toxic effects were the highest. Although the total and bioavailable Cd were high in soil, its speciation in vegetables was mainly presented as HAc-extractable fraction, which has a relatively low bioactivity. Lead and arsenic were imposing a serious threat on the local residents via vegetable consumption.     

阳宗海沉积物中磷的稳定性

絮凝剂(Fe Cl3)治理阳宗海砷污染的过程中,水体中的磷被大量沉积进入底泥,弄清其是否会在环境条件变化后发生反溶形成二次污染对湖泊富营养化防治具有重要意义。通过模拟实验模拟泥-水界面p H变化、物理扰动和微生物活动的变化,旨在分析这些环境因子变化对沉积物中磷溶出的影响。结果表明,阳宗海水体在目前这种磷浓度下,底泥的磷会随时间的增加而溶出再次造成水体磷污染,当暴露在清洁水条件下时磷的释放率会增加;这种由于絮凝剂吸附沉淀到湖底的磷,在上覆水p H增加0.5时底泥磷解吸附释放速率增加;每年秋季湖泊上下层水的交换活动会造成水体磷浓度的季节性升高,形成不可忽视的磷内源。而夏季水温分层导致湖泊底部厌氧,使厌氧微生物活性增强,这将进一步促进底泥中磷的释放。     

Biodegradation of methyl red by Bacillus sp. strain UN2: decolorization capacity,metabolites characterization,and enzyme analysis

Azo dyes are recalcitrant and refractory pollutants that constitute a significant menace to the environment. The present study is focused on exploring the capability of Bacillus sp. strain UN2 for application in methyl red (MR) degradation. Effects of physicochemical parameters (pH of medium, temperature, initial concentration of dye, and composition of the medium) were studied in detail. The suitable pH and temperature range for MR degradation by strain UN2 were respectively 7.0–9.0 and 30–40 °C, and the optimal pH value and temperature were respectively 8.0 and 35 °C. Mg²⁺ and Mn²⁺ (1 mM) were found to significantly accelerate the MR removal rate, while the enhancement by either Fe³⁺ or Fe²⁺ was slight. Under the optimal degradation conditions, strain UN2 exhibited greater than 98 % degradation of the toxic azo dye MR (100 ppm) within 30 min. Analysis of samples from decolorized culture flasks confirmed biodegradation of MR into two prime metabolites: N,N′dimethyl-p-phenyle-nediamine and 2-aminobenzoic acid. A study of the enzymes responsible for the biodegradation of MR, in the control and cells obtained during (10 min) and after (30 min) degradation, showed a significant increase in the activities of azoreductase, laccase, and NADH-DCIP reductase. Furthermore, a phytotoxicity analysis demonstrated that the germination inhibition was almost eliminated for both the plants Triticum aestivum and Sorghum bicolor by MR metabolites at 100 mg/L concentration, yet the germination inhibition of parent dye was significant. Consequently, the high efficiency of MR degradation enables this strain to be a potential candidate for bioremediation of wastewater containing MR.     

Distribution and ecological risk assessment of organochlorine pesticides in surface sediments from the East Lake,China

Organochlorine pesticides (OCPs) are ubiquitous pollutants, and their presence in urban lakes is a concern for human and ecological health. Surface sediments in the East Lake, China, were collected in winter 2012 and summer 2013 to investigate concentrations, distribution patterns, possible sources, and potential ecological risks of OCPs in this area. The total concentrations of 14 OCPs ranged from 6.3 to 400 ng g^?1 dry weight (dw) with an average concentration of 79 ng g^?1 dw. The mean values of hexachlorocyclohexanes (HCHs) (α-, β-, γ-, and δ-HCH) and dichlorodiphenyltrichloroethanes (DDTs) (p,p’-DDE, p,p’-DDD, and p,p’-DDT) were 36 and 7.6 ng g^?1 dw, accounting for 45 and 10 % of the total OCPs, respectively. The concentrations of OCPs in sediment samples collected in winter were significantly higher than those in summer, especially the HCHs, of which in winter were two times greater than summer. Composition analyses indicated that DDTs and endosulfan were mainly from historical contribution. Historical use of technical HCH and new input of lindane were probably the source of HCHs in the East Lake. Most sampling sites of HCHs and DDTs were found to have the potential ecological risk based on levels specified in the sediment quality standards.     

镍基催化剂对污泥微波热解制生物气效能的影响

为实现污水污泥减量化、无害化及资源化的目标,在微波热解污水污泥基础上,进行了镍基催化剂对制取生物气效能影响的研究。采用元素分析对污泥元素进行检测,气/质联用分析(GC-MS)和气相色谱(GC)对热解生物气的组成和含量进行测定。实验结果表明,镍基催化剂的添加对微波热解污水污泥制取生物气有较大促进作用。5%添加量与800℃热解终温条件下具有最佳催化效果:生物气中H2、CO产量最大,H2产量由29 g/kg增加到35.8 g/kg,提升23.4%,CO产量由302.7 g/kg增加到383.3 g/kg,提升26.6%;同时催化剂还能提高热能利用效率,降低热解终温,即5%添加量在700℃热解终温时可达到空白800℃时的产气效果;镍基催化剂主要在500~600℃时发挥催化作用,加快了H2和CO的释放。微波热解污泥制取的生物气具有产量大、富含H2与CO等优点,可推动污水污泥的资源化进程。     

Fenton氧化与铁炭微电解组合预处理DMF废水

对COD表征模拟废水中DMF去除率的可行性进行了探讨。在此基础上,分别对铁炭微电解、Fenton氧化-铁炭微电解和铁炭微电解-Fenton氧化组合工艺对DMF废水的处理效果进行分析,结果表明,Fenton氧化-铁炭微电解工艺的处理效果较好。在pH=5,反应时间为1 h,FeSO4·7H2O投加量为1 000 mg/L、H2O2投加量为2.67 mL/L和不曝气的最佳反应条件下,Fenton氧化-铁炭微电解工艺对实际废水和废液中COD的去除率分别达到66.67%和72.22%,从而验证了该工艺处理DMF废水的可行性。此外,Fenton氧化处理DMF废水过程实际上是将酰胺基团和羰基的不饱和双键氧化分解的过程。     

油田压裂返排液处理技术实验研究

油气井压裂作业过程中产生的压裂返排液已成为当前油田水体的主要污染源之一。文章对吉林油田公司压裂返排液处理工艺进行了实验研究。结果表明:在采用絮凝、微波强氧化、活性炭毡处理、纳滤/反渗透集成处理工艺后,压裂返排液CODCr可以达到GB 8978-1996《污水综合排放标准》一级标准要求。该研究为压裂返排液处理装置的设计和现场实施提供了实验基础。