Biokinetic modeling of heavy metals in earthworms

Studies concerning bioaccumulation kinetics and bioconcentration factor (BCF) of heavy metals like zinc (Zn), lead (Pb), chromium (Cr), cadmium (Cd), and copper (Cu) in earthworm Eudrilus eugeniae tissues including integument, gizzard, clitellum, and head region were undertaken. Calculated BCF, predicted K _ow, and predicted K _oc showed a significant correlation between heavy metals in different earthworm tissues, in substrate spiked with heavy metals. The regression coefficient (r ²) between heavy metal uptake concentration and exposure time varied between 0.73 and 0.99, indicating significant correlation. The K _oc was a maximum of 13.9016 in case of Cu and integument at an exposure time of 100 days and a minimum of 0.1114 in case of Cr with respect to head at the same exposure time. Earthworms accumulated heavy metals following chronic exposure to municipal solid waste containing heavy metals. BCF and uptake rate kinetics of heavy metals were calculated and showed increased values in head tissue followed by integument.     

异丙甲草胺及其S型对映体对蚯蚓的急性毒性差异

采用OECD标准滤纸接触法、人工土壤法及自然土壤法研究了异丙甲草胺及其S型对映体对蚯蚓的急性致死作用及手性差异.结果表明,3种方法相比较,滤纸染毒法结果置信区间最大,可靠性较差.自然土壤中Rac-异丙甲草胺及S-异丙甲草胺对蚯蚓的急性毒性大于人工土壤;根据毒性分级,Rac-异丙甲草胺及其S型对映体均属于低毒级农药;3种试验方法所得的Rac-异丙甲草胺及S-异丙甲草胺对蚯蚓的LC50差别不大,表明这2种农药对蚯蚓急性毒性的手性差异较小.     

Responses of the earthworm Eisenia andrei exposed to sublethal aluminium levels in an artificial soil substrate

Industrial discharges of Al are increasingly common. In this study, the activities of three antioxidases, malondialdehyde (MDA) content and changes in coelomocytes were investigated in earthworms (Eisenia andrei) exposed to different concentrations of aluminium chloride (range 0–200 mg Al kg^?1 dry soil) in artificial soils for 32 days. Within the first 16 days of Al exposure, catalase activity was elevated in most treatments, while the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were inhibited in all treatments. After 16 days exposure, SOD and GSH-Px activities returned to normal at lower Al concentrations, but were still inhibited at higher concentrations, hence the inhibition of SOD and GSH-Px showed some exposure-level dependence during the late exposure phase. MDA content was significantly elevated from 16 days after initial exposure. Neutral Red retention time of coelomocytes decreased at the highest exposure concentrations after 32 days, and an increased proportion of cells showing membrane damage was also observed at this time using flow cytometry. We conclude that excessive Al in soils can cause oxidative stress and cell damage in earthworms. Hence, Al accumulation in the environment may present an ecological hazard through suppression of the important functions of earthworms in soil ecosystems.     

PBS共聚物对蚯蚓的蛋白质含量和纤维素酶活性的影响

以赤子爱胜蚓Eisennia foetida为研究对象,在滤纸接触法的基础上,采用自然土壤法进行急性毒性试验,研究了不同相对分子质量的PBS-co-PCL共聚物对蚯蚓蛋白质含量和纤维素酶活性的毒性效应。研究结果表明：随着暴露时间的增长,蚯蚓蛋白质含量呈现先增加后减小的趋势;第7天时,数均相对分子质量（Mn）为8.0×103的聚合物对蛋白质的影响较明显;第14天时,相对分子质量（Mn）为1.6×104和2.8×104的聚合物对蛋白质的影响较明显。聚合物相对分子质量（Mn）为8.0×103处理组中,纤维素酶活性受到的抑制作用较明显,聚合物含量为2.5%时,抑制作用达到最大。但是随着暴露时间的增长,这种抑制作用逐渐减小,即影响是暂时性的,纤维素酶活性变化比蛋白质含量变化更敏感。以上结果表明蚯蚓在实验过程中没有出现致病或致死现象,即聚合物对蚯蚓的影响较小。     

不同生态床对剩余污泥脱水和稳定化的影响

对比分析传统干化床、芦苇生态床及芦苇-蚯蚓复合生态床3种处理方式对城镇污水处理厂剩余污泥的处理效果. 结果表明:传统干化床处理简单易行、成本低,但脱水效率低,处理15 d后污泥含水率仍在79.8%左右. 芦苇生态床较传统干化床具有明显优势,其处置后污泥含水率可降至67.8%,但其对有机质、TN、TP的去除效果不明显. 芦苇-蚯蚓复合生态床对污泥脱水效果最佳:①污泥含水率由原来的95.1%降至44.4%,体积明显减少,达到了污泥减量化的目标;②扫描电镜试验显示,处理后污泥具有孔隙及片状结构,有利于水分散失;③污泥中w(有机质)、w(TN)、w(TP)分别降低了14.5%、20.3%和13.2%左右. 热重分析发现,污泥中不稳定化合物含量有所降低. 经芦苇-蚯蚓复合生态床处理后,Cu、Ni、Zn、Cr残渣态所占比例分别由原污泥的3.2%、23.7%、15.2%、55.8%增至73.3%、43.1%、78.3%和78.6%,大幅降低了重金属的迁移风险,并且污泥红外图谱显示─COOH和酰胺明显增多,有利于重金属的稳定. 综上,复合生态床可有效实现污泥减量,并且降低了二次污染的风险.      

城市垃圾填埋场覆盖蚓粪土对作物生长的影响研究

试验研究了在城市垃圾填埋场上覆盖蚓粪土、紫色土、垃圾渣土对三种作物的主品质的影响，结果表明三种作物在三种覆盖物中均可生长，且生长状况好，而万以覆盖蚓粪 土中作物生长快、生物产量和蛋白质含量高，作物可食部分的重金属含量未超标，作物品质好，但覆盖紫色土和垃圾渣土中，作物可食部分的重金属含量部分或大部分超标，尤以覆盖垃圾渣土中超标最严重可见蚓粪土宜作垃圾埴埋复垦的覆盖材料。     

Monitoring of soil heavy metal pollution by earthworm

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城镇污水处理最佳实用技术新进展

目前我国城镇迫切需要经济、高效、节能、技术先进可靠的城市污水处理工艺和技术,即所谓的"三低一少”技术."三低一少”技术是指低建设费用,低运行费用,低操作管理需求,二次污染物排放少的城镇污水处理技术.国内新研究开发的厌氧水解-高负荷生物滤池和蚯蚓生态滤池就是其中成功的代表.通过技术经济指标等方面的比较可以看出,厌氧水解-高负荷生物滤池和蚯蚓生态滤池这两种新技术在污水处理效果、剩余污泥产率方面优于传统的活性污泥法工艺,并可节约20%～45%的工程造价,50%～65%的运行费用,操作管理简单方便,对处于目前发展阶段的我国中小城镇具有巨大的应用潜力.     

蚯蚓抗菌肽EABP-1的分离纯化及部分性质

经硫酸铵沉淀、超滤和阳离子交换分离 ,得到了一蚯蚓抗菌肽EABP 1,该肽的最大紫外吸收在 2 77.16nm ,SDS PAGE结果表明其Mr≈ 2 0× 10 3,精确的分子量没有确定 .最小抑菌浓度 (ρMIC)实验表明 ,EABP 1对鹑鸡肠球菌(Enterococcusgallinarum)、绿脓杆菌 (Pseudomonaspyocyanea)、鲍氏不动 (Acinetobacterbaumanii)、土生克雷伯 (Kleb siellaterrigena)的 ρMIC为 11.4μg/mL ,对粪肠球菌 (Enterococcusfaecalis)的 ρMIC为 2 2 .8μg/mL ,对真菌白色念株菌(Candidaalbicans)没有表现为完全的抑制作用 .图 1表 1参 10     

铜暴露下赤子爱胜蚓（Eisenia foetida）活体基因的损伤研究

通过碱性单细胞凝胶电泳法研究了Cu2+暴露剂量对赤子爱胜蚓(Eiseniafoetida)活体基因损伤的动态影响.结果显示:不添加Cu2+的对照组和添加Cu2+的处理组蚯蚓体腔细胞尾部DNA含量和尾长均呈非正态分布(p<0.05);在暴露72h时,125mg·L-1Cu2+处理组尾部DNA含量值最大,为41.44%,100mg·L-1Cu2+处理组尾长值最大,为33.79μm;随着Cu2+暴露剂量的增加,尾部DNA含量和尾长损伤频率增加;对照组和处理组的尾部DNA含量和尾长之间均存在显著性差异(p<0.05),Spearman非参数相关分析表明,尾部DNA百分含量和尾长之间呈显著相关(p<0.01,n=21),Cu2+暴露浓度与尾部DNA百分含量、尾长具有良好的剂量-构效关系(p<0.01).在125mg·L-1Cu2+浓度下暴露72h时蚯蚓的基因损伤程度达到最大,损伤程度为3级.可见,蚯蚓DNA生物标志物是重金属污染基因毒理诊断的重要指标,碱性SCGE试验是检测Cu2+暴露对赤子爱胜蚓活体基因损伤的有效手段.