Vermicomposting as an effective approach to municipal sewage sludge management through optimization of the selected process variables.

In most developing countries, municipal sewage sludge end-use practices appear unsustainable; rather, it poses environmental concerns. This study examined the potential of vermicomposting of municipal sewage sludge and its blend with other biowaste for agricultural application. Using a response surface methodology and the Box-Behnken design in Design Expert Software (Version 10.0.7), the current study optimized the moisture content (60-90%), turning frequency (1-3 turnings/week), and substrate mixing ratios (50:50 to 80:20 wt.%) to maximize the content of nitrogen, phosphorus, and potassium. As a result, an optimal moisture content (72%), substrate mixing ratio (72.34:27.6 wt.%), and turning frequency (2 per week), producing a promising-quality vermicompost with a maximum yield of nitrogen (2.76%), phosphorus (1.80%), and potassium (1.88%) is achieved. Thus, vermicomposting can effectively turn the concerning municipal sewage sludge into useful agricultural input for its sustainable management.

Effects of soybean oil exposure on the survival, reproduction, biochemical responses, and gut microbiome of the earthworm Eisenia fetida.

With increasing production of kitchen waste, cooking oil gradually enters the soil, where it can negatively affect soil fauna. In this study, we explored the effects of soybean oil on the survival, growth, reproduction, tissue structure, biochemical responses, mRNA expression, and gut microbiome of earthworms (Eisenia fetida). The median lethal concentration of soybean oil was found to be 15.59%. Earthworm growth and reproduction were significantly inhibited following exposure to a sublethal concentration of soybean oil (1/3 LC50, 5.2%). The activity of the antioxidant enzymes total superoxide dismutase (T-SOD), peroxidase (POD), and catalase (CAT) were affected under soybean oil exposure. The glutathione (GSH) content decreased significantly, whereas that of the lipid peroxide malondialdehyde (MDA) increased significantly after soybean oil exposure. mRNA expression levels of the SOD, metallothionein (MT), lysenin and lysozyme were significantly upregulated. The abundance of Bacteroides species, which are related to mineral oil repair, and Muribaculaceae species, which are related to immune regulation, increased within the earthworm intestine. These results indicate that soybean oil waste is toxic to earthworms. Thus, earthworms deployed defense mechanisms involving antioxidant system and gut microbiota for protection against soybean oil exposure-induced stress.

Ecotoxicological evaluation of oxidative stress-mediated neurotoxic effects, genetic toxicity, behavioral disorders, and the corresponding mechanisms induced by fluorene-contaminated soil targeted to earthworm (Eisenia fetida) brain.

Fluorene is a commonly identified PAH pollutant in soil and exhibits various worrisome hazardous effects to soil organisms. Currently, the toxicity profiles of fluorene on earthworm brain are rare, and the mechanisms and their corresponding pathways involved in fluorene-triggered neurotoxicity, genotoxicity, and behavior changes have not been reported hitherto. Herein, earthworm (Eisenia fetida) brain was chosen as targeted receptor to explore the neurotoxic effects, genetic toxicity, behavioral disorders, and related mechanisms caused by fluorene-induced oxidative stress pathways. The results showed excess fluorene initiated the release of excessive quantities of ROS in earthworm brain, which have caused oxidative stress and accompanied by serious oxidative effects, including LPO (lipid peroxidation) and DNA injury. To minimize the damage effects, the antioxidant defense mechanisms (antioxidant enzymes and non-enzymatic antioxidants) were activated, and entailed a decrease of the antioxidant capacity in E. fetida brain, which, in turn, causes further ROS-induced ROS release. Exposure of fluorene induced the abnormal mRNA expression of genes relevant to oxidative stress (e.g., GST, SOD, CAT, GPx, MT, and Hsp70) and neurotoxicity (e.g., H02, C04, D06, and E08) in E. fetida brain. Specifically, fluorene can bind directly to AChE, destroying the conformation of this protein, and even affecting its physiological functions. This occurrence caused the inhibition of AChE activity and excess ACh accumulation at the nicotinic post-synaptic membrane, finally triggering neurotoxicity by activation of pathways related to oxidative stress. Moreover, the avoidance responses and burrowing behavior were obviously disturbed by oxidative stress-induced neurotoxicity after exposure to fluorene. The results form IBR suggested more severe poisoning effects to E. fetida brain initiated by high-dose and long-term exposure of fluorene. Among, oxidative stress injury and genotoxic potential are more sensitive endpoint than others. Collectively, fluorene stress can provoke potential neurotoxicity, genotoxicity, and behavioral disturbances targeted to E. fetida brain through the ROS-mediated pathways involving oxidative stress. These findings are of great significance to estimate the detrimental effects of fluorene and the corresponding mechanisms on soil eco-safety.

A green approach to copper biodetoxification and sustainable agriculture application by vermicomposting in pig manure.

A green approach of copper (Cu) contaminated pig manure composting by earthworm Eisenia fetida was optimized. This work aims to assess the relationship between the bio-fertility properties and bioaccumulation of Cu during vermicomposting with five different doses of Cu. The optimal concentration of copper largely promoted the enrichment of nitrogen, phosphorus, and potassium, but the biological activities of earthworms could be inhibited once the Cu concentration exceed the threshold. When the Cu doses at 300 mg kg-1, the nutrient recovery rate (Irecovery) of available nitrogen, phosphorus and potassium reached their highest value, concomitant with largest C/N ratio reduced at 46.01 %. Moreover, nutrients recovery mechanism of total phosphorus increased up to 0.11 % h-1 and higher bioaccumulations in faces and intestine were detected by 1.79 and 0.99, respectively, during vermicomposting. The maximal enzyme activity rates (kmax) indicate that the enzyme activities, such as ROS and SOD, are sensitive bioindicators, which can be used to estimate the stress response of earthworms and Cu biotoxicity. The maximum specific growth rate (µmax) of the actinomycetes (TAct) increased gradually from 0.02 to 0.04 with the increase of Cu doses, but total fungi (TF) showed different response to µmax, which decreased firstly and then increased. It was demonstrated that Cu influenced the gut microbial community to vary the bio-fertility properties and bioaccumulation of Cu in the pig manure. All the findings refer that the vermicomposting could be the sustainable agricultural practices.

Selenium toxicity, bioaccumulation, and distribution in earthworms (Eisenia fetida) exposed to different substrates.

Selenium (Se) is an essential microelement for human or animal health. At high concentrations, it can cause Se poisoning. Human activities (such as coal burning and mining) threaten soil biota by mobilizing high levels of Se. We used the earthworm Eisenia fetida as a bio-indicator of environmental pollutants to investigate Se acute toxicity, enrichment, and distribution through exposure tests using filter paper, artificial soil and cow manure. The 24 h- and 48 h-LC50 for the filter paper contact test were 2.7 and 1.52 µg/cm2. In artificial soil test, the 14 d-LC50 and 14 d-biomass inhibition concentration (IC20) were 63.86 and 59.81 mg/kg, respectively. The cow manure resulted in a 2.2- and 2.6-fold higher LC50 and IC20 than artificial soil results, respectively. Earthworms accumulated the largest Se load (89.47 mg/kg) in artificial soil containing 80 mg Se/kg and only accumulated 90.3 mg/kg in cow manure containing 160 mg Se/kg; 46.6-60.59% of the total Se was distributed in the tail of E. fetida. The Se enrichment rate (SERSe) and bioaccumulation factor (BAFSe) scored higher in artificial soil than in cow manure with the same Se concentration exposure, and the highest SERSe was 6.21 and 6.31 mg Se/kg earthworm/d, respectively. The highest BAFSe was 1.49 in artificial soil and 0.75 in cow manure. Our results demonstrate that selenite is more toxic to earthworms living in artificial soil than in cow manure. E. fetida possesses certain Se detoxification mechanisms by distributing Se in the tail.

Transcriptomics and enzymology combined five gene expressions to reveal the responses of earthworms (Eisenia fetida) to the long-term exposure of cyantraniliprole in soil.

Cyantraniliprole is a novel diamide insecticide that acts upon the ryanodine receptor (RyR) and has broad application prospects. Accordingly, it is very important to evaluate the toxicity of cyantraniliprole to earthworms (Eisenia fetida) because of their vital role in maintaining a healthy soil ecosystem. In this study, an experiment was set up, using four concentrations (0.1, 1, 5, and 10 mg/kg) and solvent control group (0 mg/kg), to investigate the ecotoxicity of cyantraniliprole to earthworms. Our results showed that, after 28 days of exposure to cyantraniliprole, both cocoon production and the number of juvenile earthworms had decreased significantly at concentrations of either 5 or 10 mg/kg. On day 14, we measured the activities of digestive enzymes and ion pumps in the intestinal tissues of earthworms. These results revealed that cyantraniliprole exposure caused intestinal damage in earthworm, specifically changes to its intestinal enzyme activity and calcium ion content. Cyantraniliprole could lead to proteins' carbonylation under the high-dose treatments (i.e., 5 mg/kg, 10 mg/kg). At the same time, we also found that cyantraniliprole can cause the abnormal expression of key functional genes (including HSP70, CAT, RYR, ANN, and CAM genes). Moreover, the transcriptomics data showed that exposure to cyantraniliprole would affect the synthesis of carbohydrates, proteins and lipids, as well as their absorption and transformation, while cyantraniliprole would also affect signal transduction. In general, high-dose exposure to cyantraniliprole causes reproductive toxicity, genotoxicity, and intestinal damage to earthworms.

Detoxification and eco-friendly recycling of brick kiln coal ash using Eisenia fetida: A clean approach through vermitechnology.

Brick kiln coal ashes (BKCAs) are one of the major toxic byproducts of the rapidly growing construction industry in developing countries. However, eco-friendly recycling avenues for BKCAs are yet to be explored. The major objectives of the present research were to evaluate the viability of vermitechnology in transforming BKCAs into valuable products, and to examine the metal detoxification potential of Eisenia fetida BKCA-based feedstocks. BKCAs were mixed in large scale with cow dung (CD) in 1:1 and 2:1 ratios, for vermicomposting and aerobic composting; performance was assessed in comparison with CD. Vermiconverted-BKCA was then used as organic fertilizer for rice grown in poorly fertile soil. Acidic nature of BKCA feedstocks was neutralized by 30-86% in the vermireactors. Total N and available P concentrations significantly increased in the vermireactors supplemented with considerable mineralization of total organic C. Exorbitantly high K and S contents were pacified to a normal range after vermicomposting. Greater improvement in microbial biomass, respiration, fungal and bacterial growth was observed under vermicomposting against aerobic composting. Consequently, urease and phosphatase activity increased by 1-4 folds in the BKCA based vermibeds. Bioavailability of toxic metals reduced by 41-74% in the vermicomposted BKCAs. High metal accumulation by the earthworms resulted in substantial reduction of pollution load in the finished product. The field experiment demonstrated that vermiconverted-BKCA could be utilized as potential organic fertilizer for rice production, soil fertility rejuvenation, and metal detoxification. Overall, the study reveals that E. fetida could be used as an efficient contender for sanitization of toxic BKCAs.

Transcriptome analysis of genes expressed in the earthworm Eisenia fetida in response to cadmium exposure.

Eisenia fetida earthworm is an ecotoxicologically important test species to monitor various pollutants. However, there is a little knowledge about the effects of cadmium (Cd) on earthworms at the transcriptional level. Firstly, we exposed E. fetida to soils supplemented with different concentrations (10, 30, 60 mg/kg soil) of Cd. Moreover, we depicted the characterization of gene expressions with E. fetida using high-throughput profiling of gene expression. In addition, a comparison of the gene expression profiles between each Cd treatment group and the control group suggested that differential expressional genes (DEGs) mainly enriched in enzyme activity, metabolism, oxidative stress, regeneration and apoptosis pathways. 8 DEGs from these pathways had been selected randomly to confirm the data of RNA-seq. Among these DEGs, six genes (metallothionein-2, phytochelatin synthase 1a, CuZn superoxide dismutase, sex determining region Y-box 2, sex determining region Y-box 4b, TP53-regulated inhibitor of apoptosis 1-like) up-regulated and 2 genes (beta-1,4-endoglucanase, apoptosis-stimulating of p53 protein 2-like) down-regulated in response to Cd exposure. The alteration of them indicated that earthworms could reduce the toxicity and bioavailability of Cd in polluted soil ecosystems through different pathways. This work lays an important foundation for linking earthworm transcriptional level with the ecological risk of Cd in soil ecosystem.

Enhanced denitrifying phosphorus removal and mass balance in a worm reactor.

Phosphorus release is one of the disadvantages during worm predation, which has an adverse effect on wastewater treatment. In order to investigate and reveal the effects and mechanisms of worm predation on phosphorus transformation, batch experiments were conducted on a long-running worm reactor (WR). Denitrifying phosphorus removal (DPR) was observed in WR for the first time owing to the special reactor configuration and operating conditions. After DPR in WR, the concentration of supernatant phosphorus increased to 42.2 ±â€¯1.1 mg L-1 owing to bacterial phosphorus release and worm predation, which further promoted DPR in the subsequent cycle. DPR rate in the WR was 12.3 times higher than that in the blank reactor (BR). In addition, the synergistic effects of worm predation and bacterial metabolism on sludge reduction and nutrients transformation were analyzed. The sludge reduction of WR was 84.5% higher than that of BR. Bacterial metabolism played an important role in the removal of supernatant nutrients, which consumed 60.2% of total nitrogen and 55.5% of chemical oxygen demand derived from the reduced sludge. The study suggested that under certain conditions, WR could be functionalized as a bacteria selection tank to further improve the wastewater treatment efficiency. Bacterial metabolism was essential for supernatant nutrients removal during worm predation.

The role of the freshwater oligochaete Limnodrilus hoffmeisteri in the distribution of Se in a water/sediment microcosm.

Selenite(IV) and selenate(VI) are the major species of Se in the seleniferous aquatic ecosystem. The redistribution of Se in the water/sediment microcosm by bioturbation remains largely unknown. In this study, the redistribution of Se in the water/sediment microcosm by the benthic oligochaete Limnodrilus hoffmeisteri was assessed. The worms were exposed to 2-40 µg/g dry weight of Se(IV) or Se(VI) in the sediment (diet) for 2 months. The changes in the Se levels in different compartments of the microcosm (sediment, overlying water, and worms) were quantified after 2 weeks and 2 months. The subcellular distribution of Se in the worms were also evaluated. Finally, the volatilization of Se from the two Se sources was estimated. The results showed that Se concentration in the overlying water and Se bioaccumulation in the worms were increased with Se levels in the sediments. Approximately 1.6-9.8% of Se was volatilized in the absence of the worms and was intensified in the presence of the worms (2.1-25.7%). The subcellular distribution witnessed high levels of Se in the cell debris (>60%). Se(IV) and Se(VI) differ in their bioaccumulation, redistribution and the effects on the growth of the worms. Our results suggest that the bioturbation by benthos play an essential role in the redistribution of Se in the water/sediment microcosm.

[Effects of enrofloxacin and Cu combined pollution on the activities of digestive enzymes of earthworm in soil.] / æ©è¯ºæ²™æ˜Ÿå’Œé“œå¤åˆæ±¡æŸ“å¯¹èš¯èš“æ¶ˆåŒ–é ¶æ´»æ€§çš„å½±å“.

The effects of single and combined pollution of enrofloxacin and Cu on the digestive enzymes of earthworms were studied, based on the actual pollution of caused by the application of livestock feces in farmland soil. Results showed that single enrofloxacin (0.1-4 mg·kg-1, 28 d) did not affect protease, but inhibited cellulase and alkaline phosphatase, with an induced effect on acid phosphatase. Single Cu pollution (20-200 mg·kg-1, 28 d) had inhibitory effects on the four digestive enzymes in earthworms. The effects of combined exposures on the digestive enzymes were mainly negative, showing a synergistic increasing character of toxicity in cellulase and acid phosphatase activities. The response dynamics of digestive enzymes to exposure duration was regulatory response (3 d)-intense response (7 d)-reaction recovery (14 d)-chronic exposure (28 d). Chronic exposure results showed that the combined treatments containing high-dose pollutant (200 mg·kg-1 Cu or 4 mg·kg-1 ENR) had more ecological risk.

The novel phytocomponent asiaticoside-D isolated from Centella asiatica exhibits monoamine oxidase-B inhibiting potential in the rotenone degenerated cerebral ganglions of Lumbricus terrestris.

BACKGROUND: Centella asiatica (CA) is one of the most valuable herbal medicines widely being used for the treatment of various neurological ailments that are challenging for health-care providers and also is deemed to be safe and effective. PURPOSE: Monoamines (MAs) are neurotransmitters and neuromodulators that play a significant role in the neural communication, regulation of motor and cognitive functions in the brain. Neurodegeneration is associated with elevated levels of MAO-B that can lead to damaging reactive oxygen species (ROS) in the brain. The current study, evaluated the effects of asiaticoside-D (AD) from neuroprotective CA, on the levels and activities of monoamine oxidase A and B (MAO-A and B), in addition to the behavioral analysis. METHODS: Qualitative and quantitative analyses of various solvent extracts of CA were performed. The extracts were screened for antioxidant potential using 1,1-diphenyl-2-picryl hydroxyl (DPPH), 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS), hydrogen peroxide (H2O2) radical, nitric oxide (NO) radical inhibition, lipid peroxidation (LPO) and ferric reducing antioxidant power (FRAP) assays. The purification of AD was done by column, thin layer and high-performance liquid chromatographies followed by structural elucidation using IR, HR-MS, 1H and 13C NMR spectra. Docking studies were performed to assess the impact of AD on MAO-A and B.In vivo, Lumbricus terrestris were exposed to 0.4 ppm rotenone (ROT) of medium for 7 days and were subjected to co-treatment along with 15 ppm of AD from CA. At the end of experiment period, the neuronal behavior of worms was assessed. Cerebral ganglions (CGs) were removed and the m-RNA levels of MAO-A and B were analyzed by Semi Q-PCR and their activities were also analyzed. RESULTS: The ethanolic extracts exhibited higher antiradical activity against DPPH, ABTS, H2O2, LPO, FRAP, NO and vitamin C with EC50 value of 20.2, 20.9, 20.4, 22.0, 24.9, 28.1, 25.5 and 22.0 µg/ml respectively. Structural analysis by IR, HR-MS, 1H and 13C NMR spectrum have shown the structure of the isolated compound as (2α, 3ß)-2,3-dihydroxyurs-12-en-28-oicacid-O-α-L-rhamnopyranosyl-(1→4)-O-ß-d-glucopyranosyl (1→6)-ß-copyranosyl ester and was represented as AD. In silico interaction of AD with MAO-A and B residues Lys312 at distances of 1.84 Šand 2.44 Šrespectively was found to exhibit high binding energy of -9.4 and 7.4 kcal. The neuronal behavior using L. terrestris showed significant improvement against (p < 0.001) ROT impaired behavior (group II) on AD supplementation (p < 0.05). Further, the m-RNA levels and activities of MAO-A and B which were significantly altered (p < 0.001) by ROT could be effectively maintained on AD supplementation. CONCLUSION: AD was found to exert its negative impact on the levels and activities of MAO-A and B in CGs of rotenone- induced changes in L. terrestris, the property which is considered to be crucial against ROT induced neurodegenerative pathology like -Parkinsonism.

A model of the physiological and biochemical characteristics of earthworms (Eisenia fetida) in petroleum-contaminated soil.

Current researches found some terrestrial animals absorb petroleum hydrocarbons (PHCs) in oil-polluted soil. However, the absorption behaviour between various biological tissues remains unclear. The aim of our study is to determine the toxic effects and enrichment behaviours of earthworms (Eisenia fetida) in petroleum-contaminated soils and to provide a reasonable dynamics model to explain the migration of PHCs within earthworm tissues. The PHCs are divided into three fractions by equivalent carbon number. An experimental analysis of the PHC concentrations in 3 different earthworm organ systems (body-wall tissue, body fluid and gut tissue) from a contamination exposure experiment at different time intervals was implemented. A dynamics model was built to simulate the absorption mechanism. The model results perform well. The PHC concentrations in the earthworm tissues were gut > body fluid > body wall. The PHCs in the gut reached equilibrium first, and those in the body-wall tissues reached equilibrium last. In the gut tissue, the PHC concentration was different from those in the body-wall tissue and body fluid due to the influence of the feeding rule. In addition, as the length of the carbon chain increases, the molecular size increases, which makes it more difficult for petroleum hydrocarbon fractions to enter an organ system. As a result, the concentration of PHCs in each type of tissue decreases with increasing carbon chain length. This study can provide a theoretical foundation for chemical monitoring in soil.

The up-regulation of two identified wound healing specific proteins-HSP70 and lysozyme in regenerated Eisenia fetida through transcriptome analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Disposed earthworm has been used to treat various common ailments including burns, arthritis, itching, and inflammation for thousands of years in China. As their remarkable ability to fully regenerate in a scar-free manner, regenerated tissue homogenate of amputated Eisenia fetida (E. fetida) have been considered as an excellent wound repair therapy in our previous study. We have demonstrated that regenerated earthworm (G-90') can perform higher wound repair ability to non-regeneration tissue (G-90) through significant promotion of cutaneous wound repair in mice after their administration into wound beds. OBJECTIVE: In the present study, we aimed to reveal the mechanism of G-90' and to explore a potential wound healing accelerated strategy. METHODS AND RESULTS: Two functional proteins- HSP70 and lysozyme in G-90' were confirmed by cross-identification of LC-MS/MS and transcriptome analyses. Followed with semi-quantitative PCR and western blot, their expression were validated to up-regulate in 3-day regenerated tissues (G-90'). CONCLUSION: This study implies the therapeutic potency of G-90' for wound recovery and provides a new strategy to assess other natural materials targeting wound healing with the tail-amputated E .fetida as a model organism.

Effects of earthworms and effective microorganisms on the composting of sewage sludge with cassava dregs in the tropics.

The present study revealed the role of earthworm-effective microorganisms (EM) in converting sewage sludge and cassava dregs into a valuable product. Sewage sludge was toxic to earthworm, therefore it was mixed with cassava dregs in 80:20 proportions (dry weight). Treatments included mixed substrate inoculated versus not inoculated with EM and treated with or without earthworms. The pH, total organic carbon, total nitrogen, and C:N ratio decreased from the initial measurements in the range of 17.43-18.46%, 25.48-33.82%, 19.60-25.37%, and 6.68-14.05% respectively; but electrical conductivity and available phosphorus increased in the range of 113.47-158.16% and 42.42-57.58%, respectively. In addition, they interactively increased total phosphorus from 19.84-63.01% and potassium from 16.41-50.78%, and decreased the polycyclic aromatic hydrocarbons content of substrate from 21.17% to 32.14% with an increase in earthworms from 51.71 to 57.69, respectively. Earthworms and EM could be used together as an efficient method for co-composting sewage sludge plus cassava dregs in the tropics. This could be expected to result in stabilization of waste, increase in nutrients, and reduction of pollutant content. Implications: The first reports of interaction of earthworms and effective microorganisms in the treatment of sewage sludge and cassava dregs in the tropics. Co-composting was an efficient technology for treating sewage sludge and cassava dregs at the same time, in the tropics. The survival rate of the earthworms both> 95%, the highest number of cocoons (640.33) and hatchlings (4694.33) both in EW+EM (Earthworms added and EM inoculated) treatment. Earthworms and EM (Only EM inoculated) interactively increased total phosphorus and potassium content, and decreased the PAH content of substrate with increase in earthworms.

Ecotoxicological effects of fipronil, neem cake and neem extract in edaphic organisms from tropical soil.

Veterinary medicines are widely applied for the treatment and prevention of animal diseases. Consequently, animal manure contains significant amounts of environmental pollutants that are potential sources of environmental pollution when inappropriately applied in soils. This work aimed to evaluate ecotoxicological effects of doses of commercial fipronil, neem cake and neem extract in the survival and reproduction of earthworms (Eisenia andrei), enchytraeidae (Enchytraeus crypticus) and springtails (Folsomia candida) in Oxisol and tropical artificial soil (TAS). Applications of fipronil, neem cake and extract in soil were carried out according to standardized ISO methodologies by using a random experimental design with five replicates. Toxic effects of fipronil for springtails in Oxisol and TAS were observed with LC50 of 0.26 mg kg-1 (0.18-0.35 mg kg-1) and 0.29 mg kg-1 (0.22-0.37 mg kg-1), respectively. It was not observed significant toxic effects of fipronil for earthworms and enchytraeidae in both soils. However, significant amounts of juvenile earthworm and adult enchytraeidae decreased in fipronil doses higher than 10 mg kg-1. Neem cake and extract were not toxic for earthworms and enchytraeidae but, significant amounts of juvenile springtails decreased in neem cake doses from 500 to 1000 mg kg-1. It can be concluded that the use of veterinary medicines containing synthetic compounds for preventing diseases in animals needs to be controlled to avoid environmental pollution after applying manure in soil. Veterinary medicines containing natural compounds as neem cake and extract are eco-friendly and could be efficiently applied in soil in a sustainable way.

Histological anomalies and alterations in enzyme activities of the earthworm Glyphidrillus tuberosus exposed to high concentrations of phosphogypsum.

Phosphogypsum (PG) is the major solid waste generated by phosphate fertilizer plants and is used worldwide as sulfur and calcium supplement in agricultural soil. Considering the probability of elevated doses of PG during agricultural applications, this study was carried out to assess its impact on the connective tissue, tissue cholinesterase (ChE) activity, lactate dehydrogenase (LDH) activity, and lipid peroxidation (LPX) level of the tropical earthworm Glyphidrillus tuberosus (Stephenson) found in abundance in the rice fields in India. Consistent loss of connective tissue and sloughing of the intestinal epithelium were observed in worms exposed to 10%, 15%, and 20% concentrations of PG in soil over an incubation period of 30 days. ChE, LDH activities, and the level of LPX indicated highly significant variation (p < 0.01) between pre and postclitellar regions of the worm and concentrations of treatment. ChE activity was higher in postclitellar with respect to preclitellar region; however, the values for LDH activity and LPX level were higher in preclitellar region in comparison to postclitellar region in both PG treated and control worms. It was concluded that PG concentration at and beyond 10% could cause damage to muscle fibers and bring about significant alterations in these enzyme activities in G.tuberosus thus affecting the physiology and ecological functions of these worms.

Water treatment residuals as soil amendments: Examining element extractability, soil porewater concentrations and effects on earthworm behaviour and survival.

Drinking water treatment residuals (WTRs), the by-product of water clarification processes, are routinely disposed of via landfill however there is a growing body of research that demonstrates the material has great potential for beneficial use in environmental applications. Application to agricultural land is one option showing great promise (i.e. a low cost disposal route that provides organic matter input to soils and other potential benefits), however questions remain as to the impact such applications may have on earthworm survival and behaviour and also on the potential effects it may have on soil porewater chemistry. This study examined the leachability of elements within two types of WTRs (one Al- and one Fe- based) from England via 0.001 M CaCl2 solution, at varying pH, and via the Community Bureau of Reference (BCR) sequential extraction scheme. Earthworm avoidance, survival, growth, reproduction and element concentrations were examined in WTR-amended sandy soils (0%, 5%, 10%, 20% w/w), while soil porewaters were also recovered from experimental units and examined for element concentrations. The results revealed leachable element concentrations to be very low in both types of WTRs tested and so element leaching from these WTRs would be unlikely to pose any threat to ecosystems under typical agricultural soil conditions. However, when the pH was lowered to 4.4 there was a substantial release of Al from the Al-WTRs (382 mg/kg). Soil porewater element concentrations were influenced to some degree by WTR addition, warranting further examination in terms of any potential implications for nutrient supply or limitation. Earthworm avoidance of WTR-amended soil was only observed for Al-WTRs and only at the maximum applied rate (20% w/w), while survival of earthworms was not affected by either WTR type at any application rate. Earthworm growth and reproduction (cocoon production) were not affected at a statistically significant level but this needs further examination over a longer period of exposure. Increased assimilation of Al and Fe into earthworm tissues was observed at some WTR application rates (maximum fresh weight concentrations of 42 mg/kg for Al and 167 mg/kg for Fe), but these were not at levels likely to pose environmental concerns.

Screening effects of metsulfuron-methyl to collembolans and earthworms: the role of adjuvant addition on ecotoxicity.

Metsulfuron-methyl is a common active ingredient recommended for use in pre- and post-emergence control of annual grasses and broadleaf weeds in crops, usually applied with mineral oil as adjuvant to enhance its efficiency. Despite the increasing use of this herbicide, there are no information on its ecotoxicity effects to soil fauna. Avoidance and lethality tests were performed with earthworms and collembolans using tropical artificial soil contaminated with formulated products Ally® (600 g L-1 metsulfuron-methyl) and Assist® (756 g L-1 mineral oil) as adjuvant. Lethality test with earthworms showed no difference when tested with or without adjuvant. When Ally® was tested alone, it caused avoidance behavior only at high concentrations (5000 and 10,000 times field predicted dose). However, Assist® addition changed the response of soil invertebrates increasing the avoidance even at field predicted doses. The toxicity of the adjuvant was confirmed in tests exposing collembolans and earthworms to Assist® alone resulting in avoidance behavior. The results clearly show that the addition of mineral oil enhanced the ecotoxicity of metsulfuron-methyl. This study provides an important contribution to the knowledge on the toxicity of metsulfuron-methyl and indicates that adjuvants should be considered in risk assessment of pesticides, considering that under field conditions, these products are applied together.

The free energy of biomembrane and nerve excitation and the role of anesthetics.

In the electromechanical theory of nerve stimulation, the nerve impulse consists of a traveling region of solid membrane in a liquid environment. Therefore, the free energy necessary to stimulate a pulse is directly related to the free energy difference necessary to induce a phase transition in the nerve membrane. It is a function of temperature and pressure, and it is sensitively dependent on the presence of anesthetics which lower melting transitions. We investigate the free energy difference of solid and liquid membrane phases under the influence of anesthetics. We calculate stimulus-response curves of electromechanical pulses and compare them to measured stimulus-response profiles in lobster and earthworm axons. We also compare them to stimulus-response experiments on human median nerve and frog sciatic nerve published in the literature.