三种兽药在不同暴露系统对蚯蚓的急性毒性

采用人工土壤法和滤纸法对不同浓度的阿维菌素、安普霉素、磺胺二甲基嘧啶3种常用兽药对蚯蚓的急性毒性进行了研究。结果表明,用土壤法和滤纸法测定的阿维菌素对蚯蚓的半数致死浓度(LC50)分别为17.06mg·kg-1和4.63×10-3mg·cm-2,阿维菌素对蚯蚓具有一定的毒性作用,其皮肤接触毒性比土壤食入毒性更大。用滤纸法测定的安普霉素、磺胺二甲基嘧啶对蚯蚓的半数致死浓度(LC50)分别大于10mg·cm-2和15mg·cm-2;用土壤法测定安普霉素、磺胺二甲基嘧啶对蚯蚓的半数致死浓度(LC50)均大于5000mg·kg-1,表明安普霉素、磺胺二甲基嘧啶对蚯蚓的毒性较低。     

Pb对赤子爱胜蚓的影响

通过急性毒性试验测定了不同培养条件下Pb对蚯蚓的毒害作用,并通过牛粪、砖红壤培养试验,测定了蚯蚓对Pb的忍耐性,及不同形态Pb对蚯蚓体重的影响。研究结果如下:蚯蚓在在液、沙、泥土和干牛粪中的急性半致死剂量(LD50)分别为354.41mg/kg、360.95mg/kg、1228.02mg/kg和3894.62mg/kg。蚯蚓在腐熟牛粪中对Pb有很好的忍耐性,当牛粪中Pb含量达到15000mg/kg时蚯蚓依然能够生存。蚯蚓在Pb污染砖红壤生活60d后回收率和体重均有下降,在土壤Pb含量分别为400mg/kg和444mg/kg时蚯蚓的回收率和增长率下降最快,分别为0.6403和-0.4358。限制蚯蚓增长的程度大小Pb形态依次为:碳酸盐结合态>交换态>有机态>无定形氧化锰结合态>晶形氧化铁结合态>无定形氧化铁结合态>残渣态。     

Growth and survival of Eisenia fetida (Sav.) (Oligochaeta: Lumbricidae) in relation to temperature,moisture and presence of Enchytraeus albidus (Henle) (Enchytraeidae)

Summary The aim of this study was to investigate the environmental requirements of Eisenia fetida (Lumbricidae) and its relation to Enchytraeus albidus (Enchytraeidae). Specimens of Eisenia fetida were cultured at two different temperatures (15°C and 25°C) and moisture conditions (50% and 80%) in presence or absence of Enchytraeus albidus. Eisenia fetida grew best at the higher temperature and amount of moisture. Enchytraeus albidus impaired the growth of Eisenia fetida at the higher temperature. When Enchytraeus albidus was present, the mortality of Eisenia fetida increased.Interaction between Eisenia fetida and Enchytraeus albidus was shown, although the mechanisms remain unclear. These species, coexisting in the same habitat (compost), appear to have slightly different niches: Eisenia fetida favours warmer, moister conditions than Enchytraeus albidus.Dedicated to the late Prof.Dr. M.S. Ghilarov     

Terbuthylazine and carbofuran effects on growth and reproduction within three generations of Eisenia andrei (Oligochaeta)

Sublethal effects of terbuthylazine and carbofuran on the growth and reproduction of Eisenia andrei were investigated over a period of three generations. Reproduction was assessed by measuring the coccon production of worms treated chronically with pesticides. Inhibition of cocoon production was found in the parental generation. Hatchlings were raised from cocoons to provide the F₁ generation. During raising a more rapid growth of juveniles treated with terbuthylazine was observed, compared with the growth of untreated worms. The increase in vitality was also found in cocoon production. Groups treated with terbuthylazine produced more cocoons than controls. The F₂ generation was raised from hatchlings of the F₁ generation, and here, also the terbuthylazine treatments increased earthworm growth, but not cocoon production. Exposure to carbofuran decreased cocoon production in all generations. Growth of the F₁ generation was not influenced by low concentrations of carbofuran.     

Influence of dieldrin on the reproduction of the earthwormEisenia fetida (Oligochaeta)

Summary The environmental hazard of the agricultural pesticide dieldrin for the earthwormEisenia fetida was experimentally determined in order to assess and quantify sublethal effects. We determined that the non-toxic dieldrin had a negative effect on cocoon production. An inverse relationship was found between the concentration of dieldrin in the environment and the number of hatchlings per cocoon. The hatchlings were also smaller than those from the controls.Hatching success of cocoons was also adversely affected and the incubation period was longer. Knowledge of sublethal effects has predictive value in ecotoxicological work and could serve as a timely warning device of an overburdened soil ecosystem.     

Influence of earthworms and leaf litter on edaphic variables in sewage-sludge-treated soil microcosms

Summary A series of 48 greenhouse soil microcosms were established and treated with combinations of sewage sludge, Acer saccharum leaves, and the earthworms Eisenia fetida and Lumbricus terrestris. The microcosms were incubated at constant moisture for 110 days. Samples were then taken and analysed for sludge depth, organic-matter content, and waterstable soil aggregates. Weights of surface leaves and weights and numbers of surviving earthworms were determined for each microcosm. L. terrestris significantly reduced sludge depth and the surface organic-matter content of microcosm soil and significantly increased percentages of 4-mm diameter water-stable aggregates. Leaf litter also significantly reduced sludge depth and increased 4-mm water-stable aggregates. E. fetida inhibited surface feeding by L. terrestris, reduced its 110-day survival rate, and inhibited the production of 4-mm water-stable aggregates in L. terrestris treatments. Numbers of E. fetida increased in L. terrestris treatments. Sludge depth, organic-matter content and water-stable aggregates were not significantly different from controls in E. fetida treatments.     

Experiences with Novel Approaches in Earthworm Testing Alternatives (7 pp)

Goal, Scope and Background   The earthworm avoidance test is a sensitive screening test. Currently, two test designs, a two-chamber system and a six-chamber system, are under standardization. In the scope of the present study, the two test systems are compared. To assess the results, two procedures are applied, which are based on a threshold value and a statistical method. Moreover, the sensitivity of the avoidance test is compared with the sensitivity of the reproduction test. Methods   The avoidance behaviour of E. fetida towards five chemicals (Cd, Cu, PCP, TBT, TNT) was tested in a sandy and a loamy soil. The ecotoxicological test was performed according to the draft guideline ISO/DIS 17512-1. The results were compared with the number of offspring determined in the reproduction test carried out according to ISO 11268-2. Results and Discussion   The results demonstrate that the avoidance behaviour towards organic chemicals and heavy metals is a suitable screening method showing first tendencies of a chemical's effects on the habitat function of soils. Effects caused by chemical substances become visible at low concentrations and within short test periods. The sensitivity of the reproduction test and the avoidance test is principally comparable; in some cases, the avoidance test showed more sensitive reactions. The dose-response-relationships were more pronounced in the two-chamber test than in the six-chamber-system. Recommendation and Outlook   The two-chamber-system proved to be more feasible than the six-chamber-system. As the sensitivity of the avoidance test and the reproduction test is comparable, the avoidance test can be considered as a suitable screening test as well. A possible field of application may be the selection of soil samples for which the reproduction assay seems necessary. To assess contaminated or remediated soils, the earthworm reproduction test is recommended as an indicator for the habitat function of the soils. To reduce costs, the labour intensive reproduction test could be largely replaced by the avoidance test in performing the earth-worm reproduction test only for relevant samples. Before the Draft International Standard of the guideline will be adopted as an ISO Guideline, there will be sufficient time left to gain further international experience required to finalize the method.     

A comparison of the biology of Eisenia fetida and Eisenia andrei (Oligochaeta)

Summary Specimens of locally occurring Eisenia fetida were compared with specimens of E. fetida and E. andrei obtained from France. All specimens were cultured in the laboratory under controlled conditions and growth, maturation, cocoon production, hatching success, and the number of hatchlings were compared. The results showed some differences between the two forms. The eventual worm biomass was the same for both, although the growth reats and the rate at which maturity was attained differed. E. andrei had a higher cumulative cocoon production. Although the local worms resembled E. andrei in appearance their cocoon production rate resembled that of E. fetida from France. E. andrei produced higher numbers of hatchlings per cocoon. The results show that the biology of the two species/forms is similar. The study did not provide convincing proof to substantiate a taxonomic distinction between the two forms of Eisenia.