Effect on enzymes and histopathology in earthworm (Eisenia foetida) induced by triazole fungicides

Morphophysiological and Histopathological Effects of Ammonium Sulfate Fertilizer on Aporrectodea trapezoides (Dugès, 1828) Earthworm

The present study used the adult earthworm Aporrectodea trapezoides as a bioindicator species to look into the possible dangers of ammonium sulfate (AS) fertilizer. Two complementary toxicity tests were conducted to determine the LC50values, growth rate inhibition, morphological alterations, and histopathological texture of worms. The lethality test included four increasing concentrations of AS fertilizer (ranging from 2500 to 7500 mg/kg of dry soil weight (d.w.)), while sub-lethal concentrations were based on 10%, 30%, 40%, and 50% of the 14-day median lethal concentration (LC50), with a control group included for both tests. The LC(50) values for AS fertilizer were significantly higher at 7 days (4831.13 mg/kg d.w.) than at 14 days (2698.67 mg/kg d.w.) of exposure. Notably, earthworms exhibited significant growth rate inhibition under exposure to various concentrations and time durations (14/28 exposure days). Morphological alterations such as clitellar swelling, bloody lesions, whole body coiling and constriction, body strangulation, and fragmentation were accentuated steadily, with higher concentrations. Histopathological manifestations included severe injuries to the circular and longitudinal muscular layers, vacuolation, muscle layer atrophy, degradation of the chloragogenous tissue in the intestine, collapsed digestive epithelium of the pharynx with weak reserve inclusion, and fibrosis of blood vessels. These effects were primarily influenced by increasing concentrations of fertilizer and time exposure. The study highlights the strong relationship between concentration and exposure time responses and underscores the potential of A. trapezoides earthworms as valuable biological control agents against acidic ammonium sulfate fertilizer. Importantly, this research contributes to the use of such biomarkers in evaluating soil toxicity and the biological control of environmental risk assessment associated with chemical fertilizers.

Toxicological analysis of Eisenia fetida in soil under the coexistence of rockwool substrate andtricyclazole

This study investigated the combined effects of rockwool, a novel seedling substrate, and tricyclazole (TCA) on the bioavailability of TCA to Eisenia fetida. The single addition of rockwool and TCA alone to the soil inhibited the growth of E. fetida. A high concentration (300 mg·L-1) of TCA significantly decreased the biomass of E. fetida. The addition of 20-mesh rockwool reduced this effect on earthworm biomass by decreasing the soil TCA through adsorption, effectively mitigating TCA bioaccumulation in earthworms. A mechanistic analysis showed that the Mg-O functional group on the rockwool surface combined with the CC functional group in TCA to generate Mg-O-C, and the adsorption process was dominated by chemisorption. Toxicology experiments demonstrated that malondialdehyde and cellulase could be used as biomarkers of inhibitory effects of combined rockwool and TCA in soil on E. fetida. Macrogenomic analyses revealed that small particle sizes and high concentrations of rockwool caused co-stress effects on earthworms when TCA was present. When the particle size of rockwool increased, the toxic effect of TCA on earthworms instead decreased at higher rockwool concentrations. Therefore, in practical agricultural production, the particle size of rockwool can be controlled to realize the adsorption of TCA and reduce the toxic effects of TCA and rockwool on earthworms.

Development and application of an advanced algorithm for environmental risk assessment and safety management of pesticide residues in agricultural soils: Monitoring of currently used pesticide in upland soils

This study conducted the development of an advanced risk assessment algorithm system and safety management strategies using pesticide residue monitoring data from soils. To understand the status of pesticide residues in agricultural soils, monitoring was performed on 116 types of pesticides currently in use across 300 soil sites. The analysis of the monitoring results, alongside the physicochemical properties of the pesticides, led to the selection of soil half-life as a critical component in residue analysis. The use of Toxicity Exposure Ratio (TER) and Risk Quotient (RQ) for environmental risk assessment, based on monitoring data, presents limitations due to its single-component, conservative approach, which does not align with actual field conditions. Therefore, there is a necessity for a risk assessment process applicable in real-world scenarios. In this research, an efficient and accurate risk assessment algorithm system, along with a safety management model, was developed. Using the physicochemical properties of pesticides (such as soil half-life), monitoring results, and toxicity data, cluster analysis and Principal Component Analysis (PCA) validation identified four pesticides: boscalid, difenoconazole, fluquinconazole, and tebuconazole. The k-mean cluster analysis selected three priority management sites where the contribution of these four pesticides to the RQ was between 94-99 %, showing similar results to the RQ calculated for all pesticides. Predictions made with the developed model for the time required for soil half-life based RQ to drop below 1 at these priority sites showed only a 1-9 day difference between the four pesticides of concern and all pesticides, indicating comparable outcomes. The scenario of replacing high-risk pesticides with those of lower risk demonstrated that the RQ could be consistently maintained at about 50 % level. The results of this study suggest that through monitoring, evaluation, and management, effective and accurate environmental safety management of pesticides in soil can be achieved.

Differential eco-toxicological responses toward Eisenia fetida exposed to soil contaminated with naphthalene and typical metabolites

Naphthalene (NAP) was frequently detected in polycyclic aromatic hydrocarbons (PAHs)-contaminated soil, and its residues may pose an eco-toxicological threat to soil organisms. The toxic effects of NAP were closely tied to phenolic and quinone metabolites in biological metabolism. However, the present knowledge concerning the eco-toxicological impacts of NAP metabolites at the animal level is scanty. Here, we assessed the differences in the eco-toxicological responses of Eisenia fetida (E. fetida) in NAP, 1-naphthol (1-NAO) or 1,4-naphthoquinone (1,4-NQ) contaminated soils. NAP, 1-NAO, and 1,4-NQ exposure triggered the onset of oxidative stress as evidenced by the destruction of the antioxidant enzyme system. The lipid peroxidation and DNA oxidative damage levels induced by 1-NAO and 1,4-NQ were higher than those of NAP. The elevation of DNA damage varied considerably depending on differences in oxidative stress and the direct mode of action of NAP or its metabolites with DNA. All three toxicants induced different degrees of physiological damage to the body wall, but only 1, 4-NQ caused the shedding of intestinal epithelial cells. The integrated biomarker response for different exposure times illustrated that the comprehensive toxicity at the animal level was 1,4-NQ > 1-NAO > NAP, and the time-dependent trends of oxidative stress responses induced by the three toxicants were similar. At the initial stage, the antioxidant system of E. fetida responded positively to the provocation, but the ability of E. fetida to resist stimulation decreased with the prolongation of time resulting in provocation oxidative damage. This study would provide new insights into the toxicological effects and biohazard of PAHs on soil animals.

A Bibliometric Analysis on Research Progress of Earthworms in Soil Ecosystems

The earthworm, as a soil engineer, plays highly important roles in the soil ecosystem for shaping soil structure, promoting soil fertility, regulating microbial community composition and activities and decomposing soil pollutants. However, the research progresses on this important soil fauna have rarely been reviewed so far. Therefore, we conducted a bibliometric analysis of the literature published during 1900-2022, which was collected from the Web of Science Core Collection (WoS). The results showed that three periods (1900-1990, 1991-2005 and 2006-2022) could be identified in terms of the intensity of publications on the topic, and the number of publications kept increasing since 2006. The United States produced the highest publication record at the country scale, whereas Chinese Academy of Sciences was the most productive institution. Chinese institutions and authors played an active and prominent role during 2018-2022. Soil Biology & Biochemistry was the most popular journal for the topic-related research. In these publications, Professor Lavelle P was the most influential author. Based on a citation network of the top 50 cited papers, four hotspots were identified, i.e., the ecological effects of earthworms, the impact of agricultural activities on earthworms, earthworm ecotoxicology and earthworm invasion. Moreover, "impact", "biodiversity", "oxidative stress", "diversity", "response", "Eisenia fetida" and "exposure" were the emerging and active topics in recent years. This study can help us to better understand the relevant subject categories, journals, countries, institutions, authors and articles and identify the research hotspots and emerging trends in the field of soil earthworm research.

Stereoselective bioaccumulation and dissipation of four stereoisomers of cyproconazole in earthworm-soil microcosm

Cyproconazole is a representative and widely used triazole fungicide with four stereoisomers, which will bring some risks to non-target organisms. A fast analytical method on supercritical fluid chromatography-tandem mass spectrometry was established in 4 min, and the environmental hazards of chiral cyproconazole were studied in earthworm-soil microcosm, including stereoselective bioaccumulation and dissipation. In the process of bioaccumulation, the concentrations of cyproconazole stereoisomers in earthworms showed a trend of increasing first and then reaching a stable state at 6 mg/kg treatment, which was different from those at 0.6 mg/kg treatment (decease-increase-equilibrium). The concentration order was (2S,3R)- > (2S,3S)- > (2R,3R)- > (2R,3S)-cyproconazole and (2S,3S)- ≈ (2S,3R)- > (2R,3R)- > (2R,3S)-cyproconazole at 6 and 0.6 mg/kg treatments, respectively. The bioaccumulation factor (BAF) values were in the range of 0.018-0.55, showing weakly relative accumulation capacity. The dissipation of cyproconazole stereoisomers in artificial soil accorded with the first-order kinetics equation, and the half-lives were 20.1-23.6 and 7.66-8.28 days at 6 and 0.6 mg/kg treatments, respectively, without stereoselectivity and diastereoselectivity. In earthworms, the dissipation half-lives were 5.81-6.01 days with the preferential dissipation of (2R,3R)-cyproconazole. The study would help with the rational uses and risk assessments of cyproconazole.

A new paradigm in the bioremoval of lead, nickel, and cadmium using a cocktail of biosystems: a metagenomic approach

Lead (Pb), nickel (Ni), and cadmium (Cd) are known for its harmful effects on the environment. Microbial community related to soil plays a pivotal role in configuring several properties of the ecosystem. Thus, remediation of such heavy metals using multiple biosystems had shown excellent bioremoval potential. The current study demonstrates the integrated approach of Chrysopogon zizanioides in combination with earthworm Eisenia fetida augmented with VITMSJ3 potent strain for the uptake of metals like Pb, Ni, and Cd from the contaminated soil. For the uptake of heavy metals, Pb, Ni, and Cd with the concentrations of 50, 100, and 150 mg kg^-1 were supplemented in pots with plants and earthworms. C. zizanioides was used for bioremoval due to their massive fibrous root system which can absorb heavy metals. A substantial increase of 70-80% Pb, Ni, and Cd was found for VITMSJ3 augmented setup. A total of 12 earthworms were introduced in each setup and were tested for the toxicity and damages in the various internal structures. Reduction in malondialdehyde (MDA) content was observed in the earthworms with VITMSJ3 strain proving less toxicity and damages. Metagenomic analysis of the soil associated bacterial diversity was assessed by amplifying the V3V4 region of the 16S rRNA gene and the annotations were studied. Firmicutes were found to be the predominant genus with 56.65% abundance in the bioaugmented soil R (60) proving the detoxification of metals in the bioaugmented soil. Our study proved that a synergistic effect of plant and earthworm in association with potent bacterial strain had higher uptake of Pb, Ni, and Cd. Metagenomic analysis revealed the changes in microbial abundance in the soil before and after treatment.

Stereoselective accumulation and biotransformation of chiral fungicide epoxiconazole and oxidative stress, detoxification, and endogenous metabolic disturbance in earthworm (Eisenia foetida)

>80 % of applied pesticides in agriculture will enter the soil and be exposed to soil animals. Little is known about the stereoselective metabolic effects of epoxiconazole (EPO) on soil animals. In this study, EPO-mediated stereoselective enrichment, biotransformation, oxidative stress, detoxification, and global metabolic profiles in earthworms were investigated by exposure to EPO and its enantiomers at 1 mg/kg and 10 mg/kg doses. Preferential enrichment of (-)-EPO was observed, and the five transformation products (TPs) exhibited the chemically specific stereoselective accumulation with inconsistent configurations. Biochemical markers related to reactive oxygen species (ROS) and detoxification (·OH^- content, SOD, CAT, GST, and CYP450 enzymes) showed a significant stereoselective activation overall at the low-level exposure (p-value <0.05). Based on untargeted metabolomic analysis, the steroid biosynthesis and ROS-related biotransformation, glutathione metabolism, TCA cycle, amino acid metabolism, purine and pyrimidine metabolism of earthworms were significantly interfered with by EPO and its enantiomer exposure. More pronounced stereoselectivity was observed at the level of the global metabolic profile, while comparable levels of metabolic perturbations were identified at the individual metabolite level. This study provides novel insights into the stereoselective effects of the chiral fungicide EPO, and valuable evidence for soil environmental risk assessments.

Changes in antibiotic residues and the gut microbiota during ciprofloxacin administration throughout Silkie chicken development

The use of antibiotics leads to antibiotic residues in livestock and poultry products, adversely affecting human health. Ciprofloxacin (CFX) is a broad-spectrum antibiotic shared between animals and humans that is useful in treatments besides infections. However, changes in the gut microbiota caused by CFX and the possible link with the elimination of CFX residues have not been investigated. Herein, we used the Silkie chicken model to study the changes in the gut microbiota during the entire CFX-metabolic repertoire. We detected CFX residues in different tissues and showed that the elimination time of CFX from different tissues was dissimilar (liver > kidney > chest muscle > skin). Analysis of liver and kidney injury biomarkers and plasma antioxidant indices indicated slight hepatotoxicity and nephrotoxicity in the Silkie chickens. Importantly, the changes in the gut microbial community predominantly occurred early in the metabolic process. Correlation analysis revealed that the particular bacterial microbiota were associated with the pharmacokinetics of CFX in different Silkie chicken tissues (e.g., aerobic bacteria, including Escherichia and Coprococcus, and anaerobic bacteria, including Fusobacterium, Ruminococcus, Bifidobacterium, and Eubacterium). Collectively, certain microbiota may boost antibiotic metabolism and participate in restoring the microbial consortia after CFX is metabolized. Therefore, regulating the core intestinal microbiota may reduce foodborne antibiotics and accelerate the development of drug resistance.

Biochemical, transcriptomic, gut microbiome responses and defense mechanisms of the earthworm Eisenia fetida to salt stress

The accumulation of sodium chloride (NaCl) in soil is a worldwide problem with detrimental effects on the survival of soil animals. The effects of NaCl on earthworms remain unclear. Here, we show that the growth rate, cocoon production rate, annetocin precursor (ANN) mRNA level, and superoxide dismutase and catalase activities in earthworms were reduced under NaCl stress, whereas the mortality rate, reactive oxygen species (ROS) and malondialdehyde activity level increased. Histological damage to the earthworm body wall and intestine were observed under NaCl stress. NaCl stress increased DNA damage in the seminal vesicle and coelomocytes. The mRNA level of lumbrokinase, 1,3-beta-glucanse, coelomic cytolytic factor (CCF1), and alpha-amylase was significantly down-regulated, whereas that of earthworm excitatory peptides2 (EEP2) was up-regulated. From 16 S rRNA sequencing, the earthworm gut microbiota diversity decreased under NaCl stress. However, Verminephrobacter, Kluyvera, Lactobacillus, and Ochrobactrum increased under NaCl stress. These findings contribute to the risk assessment of the salt stress on soil organisms.

Enantioselective residues and toxicity effects of the chiral triazole fungicide hexaconazole in earthworms (Eisenia fetida)

The enantioselective toxic effect and environmental behavior of chiral pesticides have attracted increasing research attention. In this study, the enantioselective toxicity and residues of hexaconazole (HEX) in earthworms (Eisenia fetida) were investigated. In the present study, significant enantioselective degradation characteristics were observed in artificial soil with the R-enantiomer preferentially degrading (p < 0.05); however, no significant enantioselective bioaccumulation was observed in the earthworms (p > 0.05). The acute toxicity of S-(+)-HEX was higher than that of R-(-)-HEX in earthworms, with 48-h LC₅₀ values of 8.62 and 22.35 μg/cm², respectively. At 25 mg/kg, enantiospecific induction of oxidative stress was observed in earthworms; moreover, S-(+)-HEX had a greater influence on the contents of malonaldehyde, cytochrome P450, and 8-hydroxy-2-deoxyguanosine than R-(-)-HEX. These results were consistent with those of the enrichment analysis of differentially expressed genes. The transcriptome sequencing results showed that S-(+)-HEX had a more significant influence on steroid biosynthesis, arachidonic acid metabolism, and cell cycle processes than R-(-)-HEX, leading to abnormal biological function activities. These results indicate that S-(+)-HEX may pose a higher risk to soil organisms than R-(-)-HEX. This study suggests that the environmental risk of chiral pesticides to nontarget organisms should be assessed at the enantiomeric level.

Ecotoxicological effects of the pyrethroid insecticide tefluthrin to the earthworm Eisenia fetida: A chiral view

Tefluthrin was the first pyrethroid developed for soil treatment. There was no report about the toxicity to terrestrial invertebrates at the enantiomer level. The main objective of the present study was to investigate the enantiomer-specific acute toxicity to the earthworm Eisenia fetida and potential mechanism via multilevel response. The filter paper contact and the artificial soil method were used to detect the acute toxicity of tefluthrin enantiomers to earthworms. Histopathological examination (H&E), biochemical criterion, and comet assay were used to identify the effects and potential mechanism of toxicity. The order of acute toxicity was Z-cis-(1S,3S)-(-)-tefluthrin < Rac-tefluthrin < Z-cis-(1R,3R)-(+)-tefluthrin. H&E stained images showed that intestinal cells were suffered seriously damaged after exposed to Rac-tefluthrin, and the Z-cis-(1R,3R)-(+)-isomer. Tefluthrin and enantiomers also enantioselectively disturbed reactive oxygen species (ROS) level and enzymatic activity. Additionally, Z-cis-(1R,3R)-(+)-tefluthrin significantly increased the olive tail moment (OTM) and Trail DNA% compared with the control and other treatment groups at the concentration of 0.1 mg/kg was observed. It can be concluded that intestinal damage, body weight changes, DNA damage caused by oxidative stress that might be the primary mechanisms of tefluthrin toxicity to earthworms. The results indicated the rational use of chiral compounds in agriculture to avoid damage to the soil ecosystem.

Response of soil microorganisms and enzymes to the foliar application of Helicur 250 EW fungicide on Horderum vulgare L

The use of fungicides bears the risk of many undesirable outcomes that are manifested in, among other things, changes in the structure and activity of microorganisms. This study aimed at determining the effect of a Helicur 250 EW preparation, used to protect crops against fungal diseases, on the microbiological and biochemical activity of soil and on the development of Horderum vulgare L. The fungicide was sprayed on leaves of spring barley in the following doses (per active substance, i.e. tebuconazole, TEB): 0.046, 0.093, 0.139, 1.395, and 2.790 mg TEB plant^-1. The following indices were analyzed in the study: index of microorganisms resistance (RS) to the effects of fungicide, microorganisms colony development index (CD), microorganisms ecophysiological diversity index (EP), genetic diversity of bacteria, enzymatic activity, and effect of the fungicide on spring barley development (IF_H). The most susceptible to the effects of the fungicide turned out to be fungi. The metagenomic analysis demonstrated that the bacterial community differed in terms of structure and percentage contribution in the soil exposed to the fungicide from the control soil even at the Phylum level. However, Proteobacteria appeared to be the prevailing taxon in both soils. Bacillus arabhattai, B. soli, and B. simplex occurred exclusively in the control soil, whereas Ramlibacter tataounensis, Azospirillum palatum, and Kaistobacter terrae - exclusively in the soil contaminated with the fungicide. Helicur 250 EW suppressed activities of all soil enzymes except for arylsulfatase. In addition, it proved to be a strong inhibitor of spring barley growth and development.

Individual and cellular responses of earthworms (Eisenia fetida) to endosulfan at environmentally related concentrations

The presence of endosulfan at high levels in soils poses a potential risk for terrestrial ecosystems and human health via the food chain. Therefore, the effects of endosulfan at environmentally related doses on the terrestrial biota are of great concern. The present study measured the mortality, growth inhibition and ultrastructure of the stomach and skin of earthworms exposed to endosulfan at environmentally related concentrations to identify the individual and cellular effects of endosulfan on terrestrial biota. The results demonstrated that the growth inhibition of earthworms was significantly and positively correlated with the endosulfan dose and little mortality was found. The nuclei, microvilli and cuticles in the stomachs and skin cells of earthworms exhibited marked abnormalities. Endosulfan injured the ultrastructure of the nucleus even at low doses (0.5 mg·kg^-1). Endosulfan seriously affected stomach microvilli and the cuticle structure of the skin, and this damage increased with increased exposure time and dose. Notably, cuticle damage was worse than the microvilli damage. These experiments demonstrated that the morphological changes in the tissue ultrastructure of the earthworm were more sensitive than growth inhibition, and these changes may be used as an early warning indicator of endosulfan pollution. The degree of damage to microvilli and cuticle is a promising bio-indicator to evaluate pesticide risk. The results of this study provide evidence of endosulfan toxicity and the importance of risk assessment on the terrestrial ecosystem.

Life cycle exposure to propiconazole reduces fecundity by disrupting the steroidogenic pathway and altering DNA methylation in zebrafish (Danio rerio)

Propiconazole is fungicide widely used in agriculture, which may enter aquatic ecosystems and affect organisms. In this study, zebrafish (Danio rerio) were exposed to environmentally relevant levels of propiconazole throughout the life cycle, from embryo to sexually mature adults, and the effects on growth, reproduction, and offspring viability were investigated. To investigate the mechanisms of propiconazole action, the sex steroid hormones and the expression of genes related to the hypothalamus-pituitary-gonad-liver (HPGL) axis and DNA methylation were examined. Growth decreased in the parental zebrafish (F0) after exposure to propiconazole for 120 days. In males, increases in the levels of 17β-estradiol and vitellogenin were observed. The alterations in sex steroid hormones were regulated by the expression of genes involved with the HPGL axis. The decreases in fecundity and fertilization of the F0 was induced by the global DNA methylation, and then may result in the abnormal development of the F1. Therefore, propiconazole disrupted the steroidogenic pathway and caused changes in global DNA methylation that induced reproductive toxicity.

Acute toxicities and effects on multixenobiotic resistance activity of eight pesticides to the earthworm Eisenia andrei

Investigations of deleterious effects on non-target species, including earthworms, have been conducted for a number of pesticides, but there is a need for additional assessments of potential adverse effects. In the present study, the acute toxicity of eight pesticides to the earthworm Eisenia andrei was assessed and compared. The exposures were conducted using the filter paper contact toxicity method. Based on the 48-h LC₅₀ values, one pesticide was classified as supertoxic (combined fungicide containing difenoconazole and fludioxonil), four as extremely toxic (combined herbicide containing pethoxamide and terbuthylazine, combined fungicide containing fluopyram and tebuconazole, fungicide containing pyrimethanil, and combined fungicide containing thiram and carboxin), two as very toxic (combined fungicide containing flutriafol and thiabendazole, and herbicide containing fluroxypyr-meptyl), and one as moderately toxic (insecticide containing thiamethoxam). Additionally, effects of pesticides on the multixenobiotic resistance (MXR) activity were measured. Results showed that four pesticides caused significant effects with a recorded inhibition of the activity, which can consequently lead to a higher toxicity due to longer retention of the pesticides in the cells. Finally, for three chosen pesticides, gene expression of cat, sod, and gst was measured, and significant changes were observed. The obtained results show that earthworms could be significantly affected by pesticides commonly used in agriculture.

Hazard assessment of the pesticides KRAFT 36 EC and SCORE in a tropical natural soil using an ecotoxicological test battery

Pesticides are widely used in agricultural fields to control plant diseases, weeds, and pests; however, the unforeseeable consequences of releasing these compounds into the soil and their effects on terrestrial invertebrates are matters of grave concern. The aim of the present study was to determine the direct impact of 2 pesticides, KRAFT® 36 EC (an insecticide; a.i. abamectin) and SCORE® (a fungicide; a.i. difenoconazole), on nontarget terrestrial invertebrates. Ecotoxicological tests were performed to evaluate the chronic and acute toxicity of these compounds to a potworm (Enchytraeus crypticus), a collembolan (Folsomia candida), and a mite (Hypoaspis aculeifer). The results showed that, for both pesticides, the collembolan F. candida was the most sensitive species, followed by the enchytraeid E. crypticus and the mite H. aculeifer. Effect concentrations at 50% of organisms' reproduction calculated for F. candida, E. crypticus, and H. aculeifer were 0.06, 2.8, and >32 mg of abamectin/kg dry weight soil and 28.9, 125, and 145.5 mg of difenoconazole/kg dry weight soil, respectively. Environmentally relevant concentrations of both pesticides significantly affected the collembolan species. The existence of a potential risk from abamectin and difenoconazole for soil invertebrates even at recommended doses could be identified. Environ Toxicol Chem 2018;37:2919-2924. © 2017 SETAC.

Toxic effect of [Omim]BF4 and [Omim]Br on antioxidant stress and oxidative damage in earthworms (Eisenia fetida)

In this paper, model soil organism, earthworms (Eisenia fetida), were selected to examine the chronic toxic effect of two different ionic liquids (ILs) [Omim]BF₄ and [Omim]Br. Earthworms were put into different ILs concentrations (0, 5, 10, 20, 40 mg/kg) in artificial soil and random selected on days 7, 14, 21 and 28. Reactive oxygen species (ROS), antioxidant enzymes and detoxifying enzyme glutathione-S-transferase (GST) were researched for determination of antioxidant stress. Malondialdehyde (MDA) and olive tail moment (OTM) were researched to determine the oxidative damage. Both the pollutants had the same effect on earthworms: ILs led to accumulation of ROS, and then antioxidant enzymes and detoxification enzyme all changed to eliminate the effects of ROS, and the above process led to lipid peroxidation and DNA damage in earthworms. This paper shows that [Omim]BF₄ and [Omim]Br both caused toxicity to earthworms and had the similar toxicity levels.

Influence of soil temperature and moisture on biochemical biomarkers in earthworm and microbial activity after exposure to propiconazole and chlorantraniliprole

Predicted climate change could impact the effects that various chemicals have on organisms. Increased temperature or change in precipitation regime could either enhance or lower toxicity of pesticides. The aim of this study is to assess how change in temperature and soil moisture affect biochemical biomarkers in Eisenia fetida earthworm and microbial activity in their excrements after exposure to a fungicide - propiconazole (PCZ) and an insecticide - chlorantraniliprole (CAP). For seven days, earthworms were exposed to the pesticides under four environmental conditions comprising combinations of two different temperatures (20°C and 25°C) and two different soil water holding capacities (30% and 50%). After exposure, in the collected earthworm casts the microbial activity was measured through dehydrogenase activity (DHA) and biofilm forming ability (BFA), and in the postmitochondrial fraction of earthworms the activities of acetylcholinesterase (AChE), catalase (CAT) and glutathione-S-transferase (GST) respectively. The temperature and the soil moisture affected enzyme activities and organism's response to pesticides. It was determined that a three-way interaction (pesticide concentration, temperature and moisture) is statistically significant for the CAT and GST after the CAP exposure, and for the AChE and CAT after the PCZ exposure. Interestingly, the AChE activity was induced by both pesticides at a higher temperature tested. The most important two-way interaction that was determined occurred between the concentration and temperature applied. DHA and BFA, as markers of microbial activity, were unevenly affected by PCZ, CAP and environmental conditions. The results of this experiment demonstrate that experiments with at least two different environmental conditions can give a very good insight into some possible effects that the climate change could have on the toxicity of pesticides. The interaction of environmental factors should play a more important role in the risk assessments for pesticides.

Single and Combined Effects of Pesticide Seed Dressings and Herbicides on Earthworms, Soil Microorganisms, and Litter Decomposition

Seed dressing, i.e., the treatment of crop seeds with insecticides and/or fungicides, aiming to protect seeds from pests and diseases, is widely used in conventional agriculture. During the growing season, those crop fields often receive additional broadband herbicide applications. However, despite this broad utilization, very little is known on potential side effects or interactions between these different pesticide classes on soil organisms. In a greenhouse pot experiment, we studied single and interactive effects of seed dressing of winter wheat (Triticum aestivum L. var. Capo) with neonicotinoid insecticides and/or strobilurin and triazolinthione fungicides and an additional one-time application of a glyphosate-based herbicide on the activity of earthworms, soil microorganisms, litter decomposition, and crop growth. To further address food-web interactions, earthworms were introduced to half of the experimental units as an additional experimental factor. Seed dressings significantly reduced the surface activity of earthworms with no difference whether insecticides or fungicides were used. Moreover, seed dressing effects on earthworm activity were intensified by herbicides (significant herbicide × seed dressing interaction). Neither seed dressings nor herbicide application affected litter decomposition, soil basal respiration, microbial biomass, or specific respiration. Seed dressing did also not affect wheat growth. We conclude that interactive effects on soil biota and processes of different pesticide classes should receive more attention in ecotoxicological research.

Molecular and cellular response of earthworm Eisenia andrei (Oligochaeta, Lumbricidae) to PCDD/Fs exposure

The acute toxicity of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) was investigated in the earthworm Eisenia andrei using filter paper toxicity test. Protein content, catalase (CAT) activity, and histology of intestinal wall (chloragogen cells and intestinal epithelium) were investigated in earthworms exposed for 48 h to 0 (control), 0.5, 1.0, and 1.5 ng/cm² PCDD/Fs. The results showed an increase in the total protein content 1.56- (p = 0.104), 1.66- (p = 0.042), and 2.26-fold (p < 0.001), respectively, compared to control. The average ± standard deviation of tissular CAT activity showed no significant differences; it was 36.01 ± 7.65, 36.17 ± 9.45, 36.08 ± 9.80, and 40.01 ± 6.98 U/g tissue, respectively. However, the average specific activity of CAT ± standard deviation was significantly decreased (p < 0.001) at all doses compared to control; it was 2.93 ± 0.42, 1.93 ± 0.53, 1.80 ± 0.38, and 1.53 ± 0.44 U/mg protein, respectively. There was a progressive damage in both of the intestinal villi and the chloragogenous tissue associated with the incrementing doses. Since the toxic mixture altered the investigated biomarkers of E. andrei within 48 h, the cellular and molecular alterations resulted from the filter paper contact test could be utilized as a rapid toxicity assessment tool of environmental contamination with dioxins/furans and to assess consequent potential adverse effects on soil biota and other organisms in the ecosystem.

Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida

The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure period of 2 days; and mortality, weight loss, enzymatic activities (cholinesterase, lactate dehydrogenase and alkaline phosphatase) and histopathological effects after an exposure period of 14 days. Carbendazim was found to be highly toxic to E. fetida (LC50=2mg/kg d.w.), significantly reducing earthworm weight and showing an avoidance response at soil concentrations that are close to those predicted in rice-fields and in surrounding ecosystems. The insecticide dimethoate showed a moderate acute toxicity (LC50=28mg/kg d.w.), whereas the rest of tested pesticides showed low toxicity potential (LC50 values above 100mg/kg d.w.). For these pesticides, however, weight loss was identified as a sensitive endpoint, with NOEC values approximately 2 times or lower than the calculated LC10 values. The investigated effects on the enzymatic activities of E. fetida and the observed histopathological alterations (longitudinal and circular muscle lesions, edematous tissues, endothelial degeneration and necrosis) proved to be sensitive biomarkers to monitor pesticide contamination and are proposed as alternative measures to evaluate pesticide risks on agro-ecosystems.

Changes in exposure temperature lead to changes in pesticide toxicity to earthworms: A preliminary study

The occurring climate changes will have direct consequences to all ecosystems, including the soil ecosystems. The effects of climate change include, among other, the changes in temperature and greater frequency and intensity of extreme weather conditions. Temperature is an important factor in ecotoxicological investigations since it can act as a stressor and influence the physiological status of organisms, as well as affect the fate and transport of pollutants present in the environment. However, most of so far conducted (eco)toxicological investigations neglected the possible effects of temperature and focused solely on the effects of toxicants on organisms. Considering that temperature can contribute to the toxicity of pollutants, it is of immense importance to investigate whether the change in the exposure temperature will impact the strength of the toxic effects of pollutants present in soil ecosystems. Therefore, in the present study the toxicity of several commonly used pesticides to earthworms was assessed under different exposure temperatures (15, 20 and 25°C). The results showed that changes in exposure temperature lead to changes in susceptibility of earthworms to particular pesticides. Namely, exposures to the same pesticide concentration at different temperatures lead to different toxicity responses. Increase in exposure temperature in most cases caused increase in toxicity, whereas decrease in temperature mostly caused decrease in toxicity. This preliminary study points to need for an in-depth investigation of mechanisms by which temperature affects the toxicity of pesticides and also provides important data for future research on the effects of temperature change on the soil ecosystems.

Multilevel assessment of Cry1Ab Bt-maize straw return affecting the earthworm Eisenia fetida

Non-target effects of two varieties of Bacillus thuringiensis (Bt)-maize straw (5422Bt1 [event Bt11] and 5422CBCL [MON810]) return on the Eisenia fetida were investigated by using multilevel assessments, compared to near-isogenic non-Bt-maize (5422). 5422Bt1 straw return had no deleterious effects on adult earthworms and had significantly positive effects on juveniles over three generations. Negative, no, and positive effects on adults treated with 5422CBCL straw were observed in the 1st, 2nd and 3rd generation, respectively. Negative and positive effects were observed on juveniles produced from the 1st- and 2nd-generation adults treated with 5422CBCL straw, respectively. Glutathione peroxidase activity of earthworms from Bt-maize treatments was significantly higher than that of control on the 90th d. Translationally controlled tumour protein (TCTP) and superoxide dismutase (SOD) genes were down-regulated, while annetocin (ANN) expression was up-regulated in 5422Bt1 treatments. TCTP and SOD genes were up-regulated, while ANN and heat shock protein 70 were down-regulated in E. fetida from 5422CBCL treatments. Enzyme-linked immunosorbent assay revealed that Cry1Ab released from 5422Bt1 and 5422CBCL straw degraded rapidly on the 15th and 30th d and had a slow decline in the rest testing time. Cry1Ab concentrations in the soil, casts and guts of earthworm significantly decreased over the course of the experiment. This study was the first to evaluate generational effects of Bt-maize straw return on earthworms under laboratory conditions. The responses of enzymes activity and genes expression may contribute to better understand above different effects of Bt-maize straw return on earthworms from the 1st generation.