BP神经网络对蚯蚓滤池处理COD的模拟预测

基于蚯蚓滤池处理去除污染物的非线性特点,利用BP神经网络建立了蚯蚓滤池处理COD的基本模型结构。同时对实验数据进行了验证和预测,通过权值贡献率分析确定了各种输入因素对COD出水浓度的影响。结果表明:COD的出水模型预测值与实际值平均误差较小,模型稳定,预测效果好。输入神经元为4,隐含神经元为8,输出神经元为1,学习速率为0.1,动量为0.1,训练次数为10 000的BP神经网络模型,预测的COD出水值最接近真实值。COD进水浓度对COD出水影响最大,符合理论研究结果。BP神经网络模型建立的成功为后续生活污水智能化控制的研究提供了相应的理论基础。     

蚯蚓对毛细管渗滤沟生活污水处理效果的影响

采用添加蚯蚓的毛细管渗滤沟A和没有蚯蚓的毛细管渗滤沟B对生活污水处理进行对比实验研究,同时考察毛细管渗滤沟中蚯蚓的数量变化和添加蚯蚓对土壤结构的影响。实验结果表明：蚯蚓对毛细管渗滤沟处理有机物有促进作用,蚯蚓的加入可以改变土壤结构,提高土壤孔隙率,增加出水溶解氧。反过来,毛细管渗滤沟为蚯蚓生存、繁殖提供了适宜条件,在土...     

异丙甲草胺对蚯蚓体重及酶活性的影响

采用自然土壤法,研究了异丙甲草胺对蚯蚓体重及体内纤维素酶、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性的影响.结果表明,蚯蚓体重及纤维素酶活性在异丙甲草胺作用下均受到抑制;蚯蚓体内SOD、CAT、POD活性对异丙甲草胺响应不同,CAT活性受影响最大,POD次之,SOD最小.异丙甲草胺浓度对蚯蚓体重及体内纤维素酶和CAT活性影响显著,对SOD和POD则无显著性影响;处理时间对蚯蚓体重及体内纤维素酶、SOD、CAT和POD活性均有极显著影响;而异丙甲草胺浓度和处理时间二者交互作用对蚯蚓体内CAT和POD活性有极显著影响,对蚯蚓体重及体内纤维素酶和SOD活性则影响不大.     

外加芘在2种水稻土及其团聚体培养中的老化及其可浸提性和生物有效性的变化

老化是指有机污染物进入土壤后,随着时间的增加,其生物有效性、毒性和可浸提性会逐渐下降的现象.采用室内培养法研究了外加多环芳烃芘在2种水稻土乌栅土(潜育型水稻土)和黄泥土(潴育型水稻土)及其不同粒组团聚体中的老化现象,并采用二氯甲烷提取和蚯蚓吸收试验比较了培养老化后外加多环芳烃芘的可浸提性和生物有效性的变化.结果表明,培养90d后芘的浸提率下降了15%~23%,蚯蚓的摄食量也下降了37%~67%,说明外加有机污染物进入水稻土后发生了显著的老化现象,从而降低了其环境移动性和生物有效性.但不同粒径团聚体中老化程度没有差异,不过对蚯蚓的生物有效性存在差异.因此,并不能根据土壤中有机污染物的含量来预测其环境风险和生物有效性.     

Influence of inoculating earthworms on removal of pyrene in soils growing Festuca arundinacea

ABSTRACT

The aim of this study was to examine the potential of inoculating earthworms (Pheretima sp.) in order to enhance phytoremediation of polycyclic aromatic hydrocarbons (PAH) present in soils with the use of tall fescue (Festuca arundinacea). In particular, experiments with or without inoculating earthworms for removal of pyrene was investigated. Results showed that planting of F. arundinacea enhanced the removal of pyrene at initial content over 70 days approximately 54%–80% but only 12%–24% occurred in non-planted soils. After inoculating earthworms, the dissipation rates of pyrene in planted soils were increased up to 61%–86%, which was 6%–12% higher than those in corresponding soils without inoculating earthworms. Among all possible pathways, the contribution of plant--microbial interactions on removal of pyrene was predominant, either with (46%) or without inoculating earthworms (52%), is the primary mechanism of contaminant removal. Data suggest inoculating earthworms may be a feasible way for reinforcing removal of PAH in contaminated sites.     

Evaluation of genotoxicity of combined soil pollution by cadmium and phenanthrene on earthworm

The DNA-damaging effects of the combined pollution of heavy metal and organic contamination on earthworms were evaluated by single cell gel electrophoresis （SCGE） assay. Earthworms Eisenia andrei were exposed to single or combined test compounds in different doses of cadmium （Cd） 5, 10, 50 mg/kg and phenanthrene （Phe） 0.5, 2.5, 12.5 mg/kg with a treatment of 14 d. In SCGE assay, isolated coelomcytes and electrophoresis were employed to determine DNA damage degree after a 14-d treatment by test compounds. The results showed that there was a significant statistical difference between earthworms treated with Cd combined Phe with them treated alone with Cd or Phe. The Olive tail moment （OTM） of SCGE assay using earthworm coelomcytes appears to be a sensitive biomarker for evaluating exposure to genotoxic compounds. These tests also revealed that the interaction between Cd and Phe to DNA damaging effects was negative, and was strongly dependent on the concentration of pollution. This study corresponds to exploratory phase in order to reveal interaction effects of heavy metal and organic contamination on earthworms and then to set up more in-depth analysis to increase progressively the understanding of the genotoxicity mechanisms involved.     

Enantioseletive bioaccumulation of tebuconazole in earthworm Eisenia fetida

Methods of extraction and determination of tebuconazole enantiomers in earthworm (Eisenia fetida) were developed by capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). Both CE and HPLC have excellent resolution and recovery. The linearity ranges were 2.9-102.4 mg/kg and 3.0-99.6 mg/kg for (+)-R-tebuconazole and (-)-S-tebuconazole respectively in CE, and from 0.56 to 1000 mg/kg for both enantiomers in HPLC. Enantioselective bioaccumulation in earthworms from soil was investigated under laboratory condition at concentrations of 10 and 50 mg/kg dw in soil. The uptake kinetics of (+)-R-tebuconazole fitted the first-order kinetics well with r² 0.97 and 0.94 under 10 and 50 mg/kg dw exposure condition, respectively, while (-)-S-tebuconazole with r² 0.75 and 0.22 did not show the same. Bioaccumulation of tebuconazole in earthworm tissues was enantioselective with a preferential accumulation of (+)-R-tebuconazole. The (+)-R-tebuconazole might also have biomagnifying effect potential in earthworm food chain with biota-sediment accumulation factor (BSAF) of 1.64 kg OC/kg lip in 10 mg/kg dw exposure group and 2.61 kg OC/kg lip in 50 mg/kg dw exposure group from soil to earthworm after 36 days. Although (-)-S-tebuconazole shares the same physicochemical properties with (+)-R-tebuconazole, it did not biomagnify. BSAFs of (-)-S-tebuconazole were 0.50 kg OC/kg lip (10 mg/kg dw tebuconazole exposure) and 0.28 kg OC/kg lip (50 mg/kg dw tebuconazole exposure) after 36 days, which was possibly owing to biotransformation or metabolism in earthworm tissues.     

一种新型环境友好污水处理工艺——蚯蚓生态滤池

蚯蚓生态滤池将蚯蚓创造性地引入到污水处理系统中,延长和扩展了微生物代谢链,强化了生态系统富集与扩散、合成与分解、拮抗与协同等多种自然调控作用,实现了污水污泥的同步高效处理。滤池出水可用作绿化争农田灌溉,蚓粪污泥含水率低,减量化稳定化效果显著,较好地解决了剩余污泥的处置问题。蚯蚓生态滤池工艺高效节能,具有鲜明的“生态平衡”和“环境友好”技术特色,符合可持续发展的理念,具有技术经济竞争优势,环境效益比较显著,具有良好的实际应用前景。     

甲胺磷、乙草胺和铜单一与复合污染对黑土环境安全的胁迫研究

以黑土为环境介质,通过急性毒性试验法研究了东北黑土区普遍存在的2种农用化学品甲胺磷和乙草胺与重金属Cu对赤子爱胜蚓(Eiseniafoetida)的单一与复合毒性效应.单一毒性试验结果表明,3者对蚯蚓均有毒性,顺序为甲胺磷>乙草胺>Cu.复合毒性实验结果表明,2种有机农药与重金属Cu复合毒性效应十分复杂,与不同的浓度组合及染毒历时有关,一般随时间的延长,毒性加剧.2种有机农药通过不同途径毒害蚯蚓,复合毒性效应表现为协同作用.可见,3者对土壤生态系统环境安全性和土壤健康质量存在潜在危害,同时这几种污染物的共存进一步加大了潜在危害性,且复合毒性效应与各组浓度组合及污染暴露时间密切相关.     

蚯蚓体内过氧化物还原蛋白PRDX基因对土壤PAHs污染胁迫的转录响应

在前期建立的苯并[a]芘(benzo[a]pyrene,BaP)诱导上调表达的蚯蚓cDNA文库中,发现一种过氧化物还原蛋白peroxiredoxin6(PRDX6)基因片段,并提交到GenBank.Blastx比对与基因进化分析结果表明,该序列与已知PRDX6的最高相似率为86%,期望值为4E-30.序列分析表明,该序列具有PRDX6基因含Cys编码的一个特征motif,表明该序列属于PRDX6基因.为进一步验证蚯蚓PRDX6基因对多环芳烃污染的响应情况,使用OECD推荐方法,进行了土壤菲、芘、荧蒽和苯并芘污染对蚯蚓的毒性响应的试验(周期28 d),并采用定量PCR方法,检测了各实验组蚯蚓PRDX6基因的表达差异.结果发现,1.0 mg·kg-1的芘和苯并[a]芘均可显著上调蚯蚓PRDX6基因的表达,表明PRDX6基因可作为土壤污染引起蚯蚓抗氧化应激检测的分子标记.