Toxicity potential of Grassate® a non-selective herbicide on snails (Achachatina marginata) and earthworms (Aporrectodea longa)

The application of herbicides in agricultural practices may pose certain toxic effects on non-target species including molluscs (snails), earthworms and other soil-dwelling organisms, which would in turn put the lives of humans at great risk. This study considered the lethal and sublethal effects of Grassate®, a non-selective glyphosate-based herbicide on snails (Archachatina marginata) and earthworms (Aporrectodea longa) with regards to ecotoxicological risk assessment. The lethal concentration LC₅₀ for the test chemical averaged at 1.731?±?0.05 and 3.045?±?0.08?mg?kg^?1 for snails and earthworms, respectively. There was decrease in growth and biomass with increased concentration for the species. Growth inhibition of 11–38% in size and 7–43% in length was obtained for earthworms while 26–65% reduction in weight was reported for snails. Using the ecotoxicological risk assessment matrix, the herbicide was classified as D 4 (A; P; E) or 16 (A; P; E), which could be considered as high risk to animals, plant and the environment. Thus, if these herbicides are used uncontrollably and unregulated, further consequence could lead to harmful effects on humans who feed on snails, a rich source of protein and depend on earthworms for nutrient.     

Assessing cypermethrin-contaminated soil with three di erent earthworm test methods

A series of tests (lethal, sublethal, and behavioral) on earthworms were conducted as an eco-assessment of pesticides. In this study, the toxicity of cypermethrin-contaminating soil on adult and juvenile earthworms was assessed. Beside the acute and chronic tests, an avoidance response test was carried out. It was shown that the all-round toxicity from cypermethrin was weak on adult earthworms. Compared with adult earthworms, the toxicity of juvenile earthworms from cypermethrin especially chronic toxicity increased significantly. Growth and reproduction of earthworms appeared to be more severely a ected by cypermethrin at juvenile stage than at adult stage. Applied at 10 mg/kg, cypermethrin had obvious adverse impact on the growth of juvenile earthworms, while 20 mg/kg, cypermethrin caused significant toxic e ects in reproduction. The results also indicated that ecotoxicological risk assessment using only adult specimens may underestimate the e ects of cypermethrin on soil invertebrate populations.     

Assessing cypermethrin-contaminated soil with three different earthworm test methods

A series of tests (lethal,sublethal,and behavioral) on earthworms were conducted as an eco-assessment of pesticides.In this study,the toxicity of cypermethrin-contaminating soil on adult and juvenile earthworms was assessed.Beside the acute and chronic tests,an avoidance response test was carried out.It was shown that the all-round toxicity from cypermethrin was weak on adult earthworms.Compared with adult earthworms,the toxicity of juvenile earthworms from cypermethrin especially chronic toxicity increased...     

Reduced Density and Nest Survival of Ground‐Nesting Songbirds Relative to Earthworm Invasions in Northern Hardwood Forests

Abstract: European earthworms (Lumbricus spp.) are spreading into previously earthworm‐free forests in the United States and Canada and causing substantial changes, including homogenization of soil structure, removal of the litter layer, and reduction in arthropod abundance and species richness of understory plants. Whether these changes affect songbirds that nest and forage on the forest floor is unknown. In stands with and without earthworms in the Chequamegon‐Nicolet National Forest, Wisconsin (U.S.A.), we surveyed for, monitored nests of, and measured attributes of habitat of Ovenbirds (Seiurus aurocapillus) and Hermit Thrushes (Catharus guttatus), both ground‐dwelling songbirds, and we sampled earthworms at survey points and nests. Bird surveys indicated significantly lower densities of Ovenbirds and Hermit Thrushes in relation to Lumbricus invasions at survey point and stand extents (3.1 and 15–20 ha, respectively). Modeling of Ovenbird nest survival (i.e., the probability that nestlings successfully fledge) indicated that lower survival probabilities were associated with increased sedge cover and decreased litter depth, factors that are related to Lumbricus invasions, possibly due to reduced nest concealment or arthropod abundance. Our findings provide compelling evidence that earthworm invasions may be associated with local declines of forest songbird populations.     

蚯蚓细胞色素P450生物标记物方法研究

以蚯蚓(Eisenia fetida)为试验动物,通过强化预处理(盐水洗脱)、改变离心力和溶解微粒体膜等实验,建立了蚯蚓细胞色素P450含量的定性、定量测定方法.在此基础上,以多环芳烃(菲)为供试外源污染物,分别以滤纸接触法和土壤投加法,进行了蚯蚓细胞色素P450含量与菲污染诱导的量-效关系试验.结果表明,增加和调整离心力,加入增溶剂等方法,可有效去除干扰,使蚯蚓微粒体样品的450峰值由完全被干扰掩盖(在455～457nm处滞后出现),转变为在450nm±1nm达到最大值.滤纸接触试验(10^-6,10^-5,10^-4,10^-3和10^-2mg·mL^-1)和土壤染毒试验(1,2,4,8 mg·kg^-1)均表明,蚯蚓体内P450含量与菲浓度存在量-效关系.对土壤染毒不同诱导时间(1,3,7,14,28d)的测定结果表明,不同浓度的菲对蚯蚓毒性为诱导刺激(7d)效应和诱导抑制(14d和28d)效应,导致蚯蚓体内P450总量分别为对照组的0.99～1.41倍及0.77～0.88倍(p<0.05).蚯蚓细胞色素P450含量测定方法具有简单、快速、低耗、敏感的优点,是适合于土壤低剂量污染暴露毒性诊断的生物标记物指标.     

珍珠岩对蚯蚓同步处理污泥-狐尾藻的研究

本研究利用太平二号蚯蚓构建生物反应器,以污水处理厂脱水污泥和粉绿狐尾藻作为研究对象,探究添加不同比例的珍珠岩对蚯蚓动物反应器处理混合物的减量化、无害化和资源化效果.结果表明,添加珍珠岩能够显著提高蚯蚓动物反应器同步处理污泥-狐尾藻的效率,经反应器处理后,混合物减量化效果明显,处理后产物的pH、有机质、碱解氮和重金属含量(Cu、Pb、Cr)均表现为明显下降,电导率(EC)和速效磷显著上升.经反应器处理后,产物品质符合在pH6.5的中性和碱性土壤上的施用标准.结果显示,当珍珠岩添加比例为4%时,对动物反应器的实用性和经济性效果最佳.     

华北代表性农田的蚯蚓群落与重金属污染指示研究

对鲁中地区农田环境有害化学物质对蚯蚓群体构成的影响进行了调查,并做了重金属毒理试验。普通农田的调查显示,棕壤农田有蚯蚓3科,6属,8种;褐土农田3科,5属,6种;潮土农田3科,6属,6种。调查、分析及毒理试验显示,潮土农田中暗灰异唇蚓、湖北远盲蚓、日本杜拉蚓3个种是适用于反应指示的重金属污染敏感种,赤子爱胜蚓、微小双胸蚓、威廉腔蚓3个种是适用于积累指示的重金属污染耐受性种。      

Biochemical responses,growth and reproduction of earthworm in low density polyethylene (LDPE)

There is an unprecedented production of plastic that is accelerating its disposal while affecting the fitness of the terrestrial as well as the aquatic environment. The term microplastics refers to plastic fragments that are less than 5 mm in size and are widely distributed in the environment. Therefore, the present study intends to explore the biological response of earthworms (Eisenia fetida) toward different concentrations of low-density polyethylene. E. fetida treated with low-density polyethylene concentration (Control), 250 mg kg⁻¹, 1000 mg kg⁻¹, 6000 mg kg⁻¹, 12,000 mg kg^−1, and 25,000 mg kg⁻¹. The above ratios were thoroughly mixed with 1kg of artificial soil and tested for growth, reproduction (cocoons and hatchling count), and enzymatic activities namely superoxide dismutase, guaiacol peroxidase, glutathione-S-transferase, and glutathione reductase and molecular docking studies. No mortality was observed during the exposure period at any concentrations. On the 28th day, when compared to the control the highest decrease in body weight of earthworms was observed in 25,000 mg (28.4%) followed by 12,000 mg (12.2%) and 6000 mg (3.4%). The cocoon and hatchlings significantly declined as the dose of microplastics increases. Enzymatic activity such as SOD and POD showed declined trend as the dose increased, while GST and GR increased with an increase in microplastic concentrations on 28th day. Furthermore, molecular docking showed that LDPE can modulate the activity of all four enzymes significantly.     

Eiseniella tetraedra (Savigny, 1826) (Oligochaeta: Lumbricidae) as a bioindicator of heavy metals

The objective of this study was to assess the potential of the earthworm Eiseniella tetraedra (Savigny, 1826) as a bioindicator for cadmium (Cd) and lead (Pb) exposure. The importance of earthworms in metal pollution monitoring is widely recognized in terrestrial ecosystems. In this study, the levels of Cd and Pb in soils and earthworm tissues were studied at two locations, Polur Falls and a riverside area located in Abali, in the Elburz Mountains in Iran. At both locations the concentration of Cd and Pb in earthworms was higher than in the surrounding soils and a significant difference was found between the two stations, the latter probably attributable to the (1) amount of pesticides that are used for crop treatment in Abali and (2) presence there of clay, which is known to be rich in Cd. Data indicate that E. tetraedra is an efficient bioaccumulator of Cd and Pb and might act thus serve as a bioindicator of exposure.