Nickel oxide nanoparticles decrease the accumulation of atrazine in earthworms.

Nickel oxide nanoparticles (NiO-NPs) are common nanomaterials that may be released into the environment, affecting the toxicity of other contaminants. Atrazine (ATZ) is a commonly used herbicide that can harm organisms due to its persistence and bioaccumulation in the environment. Although the toxicity of ATZ to earthworms is well-documented, the risk of co-exposure with NiO-NPs increases as more nanoparticles accumulate in the soil. In this study, we investigated the effects and mechanisms of NiO-NPs on the accumulation of ATZ in earthworms. The results showed that after day 21, the antioxidant system of the cells under ATZ treatment alone was adversely affected, with ROS content 36.05 % higher than that of the control (CK) group. However, the addition of NiO-NPs reduced the ROS contents in the earthworms by 0.6 %- 32.3 %. Moreover, analysis of earthworm intestinal sections indicates that NiO-NPs mitigated cellular and tissue damage caused by ATZ. High-throughput sequencing revealed that NiO-NPs in earthworm intestines increased the abundance of Pseudomonas aeruginosa and Aeromonas aeruginosa. Additionally, the enhanced function of the ABC transport system in the gut resulted in lower accumulation of ATZ in earthworms. In summary, NiO-NPs can reduce the accumulation and thus the toxicity of ATZ in earthworms. Our study contributes to a deeper understanding of the effects of NiO-NPs on co-existing pollutants.

Impact of pesticides on non-target invertebrates in agricultural ecosystems.

In fact, less than 1% of applied pesticides reach their target pests, while the remainder pollute the neighboring environment and adversely impact human health as well as non-target organisms in agricultural ecosystem. Pesticides can contribute to the loss of agrobiodiversity, which are essential to maintaining the agro-ecosystem's structure and functioning in order to produce and secure enough food. This review article examines the negative effects of pesticides on non-target invertebrates including earthworms, honeybees, predators, and parasitoids. It also highlights areas where further research is needed to address unresolved issues related to pesticide exposure, aiming to improve conservation efforts for these crucial species. These organisms play crucial roles in ecosystem functioning, such as soil health, pollination, and pest control. Both lethal and sub-lethal effects of pesticides on the selected non-target invertebrates were discussed. Pesticides affect DNA integrity, enzyme activity, growth, behavior, and reproduction of earthworms even at low concentrations. Pesticides could also induce a reduction in individual survival, disruption in learning performance and memory, as well as a change in the foraging behavior of honeybees. Additionally, pesticides adversely affect population growth indices, reproduction, development, longevity, and consumption of predators and parasitoids. As a result, pesticides must pass adequate ecotoxicological risk assessment to be enlisted by regulatory authorities. Therefore, it is important to adopt integrated pest management (IPM) strategies that minimize pesticide use and promote the conservation of beneficial organisms in order to maintain agrobiodiversity and sustainable agricultural systems. Furthermore, adopting precision agriculture and organic farming lessen these negative effects as well.less than.

Co-exposure of decabromodiphenyl ethane and cadmium increases toxicity to earthworms: Enrichment, oxidative stress, damage and molecular binding mechanisms.

The increase of electronic waste worldwide has resulted in the exacerbation of combined decabromodiphenyl ethane (DBDPE) and cadmium (Cd) pollution in soil, posing a serious threat to the safety of soil organisms. However, whether combined exposure increases toxicity remains unclear. Therefore, this study primarily investigated the toxic effects of DBDPE and Cd on earthworms at the individual, tissue, and cellular levels under single and combined exposure. The results showed that the combined exposure significantly increased the enrichment of Cd in earthworms by 50.32-90.42 %. The toxicity to earthworms increased with co-exposure, primarily resulting in enhanced oxidative stress, inhibition of growth and reproduction, intensified intestinal and epidermal damage, and amplified coelomocyte apoptosis. PLS-PM analysis revealed a significant and direct relationship between the accumulation of target pollutants in earthworms and oxidative stress, damage, as well as growth and reproduction of earthworms. Furthermore, IBR analysis indicated that SOD and POD were sensitive biomarkers in earthworms. Molecular docking elucidated that DBDPE and Cd induced oxidative stress responses in earthworms through the alteration of the conformation of the two enzymes. This study enhances understanding of the mechanisms behind the toxicity of combined pollution and provides important insights for assessing e-waste contaminated soils.

Combined effects of cadmium and sulfamethoxazole on Eisenia fetida: Insights into accumulation, subcellular partitioning, biomarkers and toxicological responses.

Cadmium (Cd) and sulfamethoxazole (SMX) frequently coexist in farmlands, yet their synergistic toxicological impacts on terrestrial invertebrates remain unexplored. In this study, earthworms were exposed to artificial soils percolated with Cd (5 mg/kg), SMX (5 mg/kg) or combination of them for 7 days, followed by a 12-day elimination phase in uncontaminated soil. The uptake of Cd and SMX by the earthworms, along with their subcellular distribution, was meticulously analyzed. Additionally, a suite of biomarkers-including superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and weight loss-were evaluated to assess the health status of the earthworms and the toxicological effects of the Cd and SMX mixture. Notably, the cotreatment with Cd and SMX resulted in a significantly higher weight loss in Eisenia fetida (41.25 %) compared to exposure to Cd alone (26.84 %). Moreover, the cotreatment group exhibited substantially higher concentrations of Cd in the total internal body, fraction C (cytosol), and fraction E (tissue fragments and cell membranes) in Eisenia fetida compared to Cd alone counterparts. The combined exposure also significantly elevated the SMX levels in the total body and fraction C compared with the SMX-only treated earthworms. Additionally, Eisenia fetida subjected to the combined treatment showed markedly increased activities of SOD, CAT, and MDA compared to those treated with Cd alone. The effect addition indices (EAIs), ranging from 1.00 to 2.23, unequivocally demonstrated a synergistic effect of the combined treatments. Interestingly, relocating the earthworms to clean soil did not mitigate the observed adverse effects. These findings underscore the increased risk posed by the Cd-SMX complex to terrestrial invertebrates in agricultural areas.

Combined toxicity of polyethylene microplastics and nickel oxide nanoparticle on earthworm (Eisenia andrei): oxidative stress responses, bioavailability and joint effect.

The co-occurrence of heavy metals and microplastics (MPs) is an emerging issue that has attracted considerable attention. However, the interaction of nickel oxide nanoparticle (nano-NiO) combined with MPs in soil was poorly researched. Here, experiments were conducted to study the influence of nano-NiO (200 mg/kg) and polyethylene (PE) MPs with different concentrations (0.1, 1, and 10%) and sizes (13, 50, and 500 µm) on earthworms for 28 days. Compared to control, the damage was induced by PE and nano-NiO, which was evaluated by biomarker Integrated Biomarker Response index: version 2 (IBRv2) based on six biomarkers including SOD, POD, CAT, MDA, AChE, Na+/K+-ATPase and cellulase. The majority of the chosen biomarkers showed significant but complicated responses with increasing contaminant concentrations after 28 days of exposure. Moreover, the joint effect was assessed as antagonism by the effect addition index (EAI). Overall, this work expands our understanding of the combined toxicity of PE and nano-NiO in soil ecosystems.

Oxidative stress and DNA alteration on the earthworm Eisenia fetida exposed to four commercial pesticides.

Modern agriculture is mainly based on the use of pesticides to protect crops but their efficiency is very low, in fact, most of them reach water or soil ecosystems causing pollution and health hazards to non-target organisms. Fungicide triazoles and strobilurins based are the most widely used and require a specific effort to investigate toxicological effects on non-target species. This study evaluates the toxic effects of four commercial fungicides Prosaro® (tebuconazole and prothioconazole), Amistar®Xtra (azoxystrobin and cyproconazole), Mirador® (azoxystrobin) and Icarus® (Tebuconazole) on Eisenia fetida using several biomarkers: lipid peroxidation (LPO), catalase activity (CAT), glutathione S-transferase (GST), total glutathione (GSHt), DNA fragmentation (comet assay) and lysozyme activity tested for the first time in E. fetida. The exposure to Mirador® and AmistarXtra® caused an imbalance of ROS species, leading to the inhibition of the immune system. AmistarXtra® and Prosaro®, composed of two active ingredients, induced significant DNA alteration, indicating genotoxic effects. This study broadened our knowledge of the effects of pesticide product formulations on earthworms and showed the need for improvement in the evaluation of toxicological risk deriving from the changing of physicochemical and toxicological properties that occur when a commercial formulation contains more than one active ingredient and several unknown co-formulants.

Phytometabolites from coral jasmine flower extracts: Toxic effects on Spodoptera litura and enzyme inhibition in nontarget earthworm Eisenia fetida as an alternative approach.

Green pesticides, derived from natural sources, have gained wider attention as an alternative to synthetic pesticides for managing polyphagous pests, such as Spodoptera litura. In this study, the methanolic flower extract of Nyctanthes arbor-tristis (Mx-Na-t) was subjected to chemical screening, and 3-hydroxy-1,2-dimethyl-4(1H)-pyridone (3H-dp) and tyrosol (Ty-ol) were identified as the major derivatives. The toxic effects of Mx-Na-t (500 ppm) were highest in third-instar S. litura larvae (96.4%), while those of 3H-dp and Ty-ol (5 ppm) were highest in second-instar larvae (76.5% and 81.4%, respectively). The growth and development of S. litura larvae and pupae were significantly reduced by all three treatments. Fecundity rates were also reduced by all treatments [from 1020 eggs (control) to 540 eggs by Mx-Na-t treatment, 741 eggs by 3H-dp treatment, and 721 eggs by Ty-ol treatment]. The extract and its active constituents decreased adult emergence and slowed total larval development in a dose-dependent manner. A decrease was noted in the major gut enzymes of young S. litura larvae exposed to Mx-Na-t, 3H-dp, and Ty-ol. Moreover, midgut tissues of fourth-instar larvae were severely damaged by Mx-Na-t (250 ppm), 3H-dp (2.5 ppm), and Ty-ol (2.5 ppm); the treatments induced structural damage to the epithelial cells and gut lumen. The earthworm Eisenia fetida was used to assess nontarget toxicity. Compared with cypermethrin, the phytochemicals exhibited minimal effects on the earthworm's detoxifying enzymes superoxide dismutase and catalase after 14 days of treatment. Moreover, in silico predictions using BeeTox and ProTox-II indicated little or no toxicity of 3H-dp and Ty-ol toward honey bees and other nontarget species.

Co-exposure to deltamethrin and cyazofamid: variations in enzyme activity and gene transcription in the earthworm (Eisenia fetida).

Pesticide formulations are typically applied as mixtures, and their synergistic effects can increase toxicity to the organisms in the environment. Despite pesticide mixtures being the leading cause of pesticide exposure incidents, little attention has been given to assessing their combined toxicity and interactions. This survey purposed to reveal the cumulative toxic effects of deltamethrin (DEL) and cyazofamid (CYA) on earthworms (Eisenia fetida) by examining multiple endpoints. Our findings revealed that the LC50 values of DEL for E. fetida, following 7- and 14-day exposures, ranged from 887.7 (728-1095) to 1552 (1226-2298) mg kg-1, while those of CYA ranged from 316.8 (246.2-489.4) to 483.2 (326.1-1202) mg kg-1. The combinations of DEL and CYA induced synergistic influences on the organisms. The contents of Cu/Zn-SOD and CarE showed significant variations when exposed to DEL, CYA, and their combinations compared to the untreated group. Furthermore, the mixture administration resulted in more pronounced alterations in the expression of five genes (hsp70, tctp, gst, mt, and crt) associated with cellular stress, carcinogenesis, detoxification, and endoplasmic reticulum compared to single exposures. In conclusion, our comprehensive findings provided detailed insights into the cumulative toxic effects of chemical mixtures across miscellaneous endpoints and concentration ranges. These results underscored the importance of considering mixture administration during ecological risk evaluations of chemicals.

Evaluation of the combined toxicity of multi-walled carbon nanotubes and cadmium on earthworms in soil using multi-level biomarkers.

The coexistence of multi-walled carbon nanotubes (MWCNTs) with cadmium (Cd) in soil may cause the combined biological effects, but few study reported about their joint toxic effects on earthworms. Therefore, this study investigated the effects of sub-lethal levels of MWCNTs (10, 50, 100 mg/kg) and Cd (2.0, 10 mg/kg) on earthworms Eisenia fetida for 14 days. The changes in multi-level biomarkers of growth inhibition rate, cytochrome P450 isoenzymes (CYP1A2, 2C9 and 3A4), and small molecular metabolites (metabolomics) were determined. The toxic interaction between MWCNTs and Cd was characterized by the combination of the biomarker integration index (BRI), joint effect index concentration addition index (CAI), and the effect concentration addition index (EAI). The results showed that the single MWCNTs exposure caused insignificant change in most biomarkers, while the combined exposure of MWCNTs (50-100 mg/kg) and 10 mg/kg Cd led to significant changes in ten most important metabolites identified by metabolomics and activities of CYP1A2, 2C9, and 3A4. Compared with the toxicity of Cd alone, the combined toxicity of the mixture was significantly reduced. According to the integration of BRI and CAI/EAI, a clearly antagonistic interaction at relatively low effects was observed between MWCNTs and Cd. The responses of multiple biomarkers suggest the toxic action mode of the mixture on earthworms was related to the oxidative injury, and the disruption of amino acid, purine, and pyrimidine metabolism, and the urea cycle.

Bisphenol A affects the pulse rate of Lumbriculus variegatus via an estrogenic mechanism.

Invertebrates are recognized as important species in endocrine disrupting chemical (EDC) testing. However, it is poorly understood whether the effects of EDCs in invertebrates are mediated by hormonal mechanisms. Previously, we showed that bisphenol A (BPA) affected the physiology of the freshwater oligochaete Lumbriculus variegatus. In the present study, we examined the mechanism of the impact of BPA on L. variegatus, using pulse rate of the dorsal blood vessel (DBV) as an endpoint. Both long term and acute exposures to BPA increased the pulsing rate of DBV. The former had a distinct inverted-U dose response relationship with a most efficacious dose of 10-9 M, which increased the pulse rate from 8.97 to 10.9 beats/min. The effects of BPA were mimicked by the synthetic estrogen ethinylestradiol with a most efficacious dose of 10-12 M. Interestingly E2 had no effect on pulsing rate, either acute or long term. The sensitivity of L. variegatus to estrogens were exquisite, with detectable effects at 10-14 to 10-10 M range. Both the long term and acute effects of BPA were partially or fully blocked by various vertebrate estrogen receptor (ER) antagonists, including ICI 182,780, MPP and G15. Our results suggest that the impact of BPA on pulsing rate of L. variegatus is likely mediated by an estrogenic mechanism instead of general toxicity. The exceptionally high sensitivity of L. variegatus to some estrogens makes it a possible tool for estrogenic EDC screening.

Assessing potential indicator of endocrine-disrupting property of chemicals using soil invertebrates.

Vitellogenin has been regarded as an acceptable indicator for evaluating the endocrine-disrupting property of chemicals using fish. However, the endocrine-disrupting property of chemicals has been rarely evaluated using soil species. This study aimed to find evidence that endocrine-disrupting chemicals (including the natural hormones estradiol and dihydrotestosterone) can affect the reproductive organs of earthworms. Earthworms were exposed to 17ß-estradiol, dihydrotestosterone, bisphenol A, and methylparaben for seven days. The four EDCs inhibited normal oogenesis and maturation of oocytes in earthworm ovary, and dihydrotestosterone and bisphenol A were observed to damage earthworm seminal vesicle tissues and inhibit normal spermatogenesis. The evidence showed that the tested EDCs have an adverse effect on female and male reproductive systems of soil invertebrates. The results suggest that the evaluations of oogenesis and spermatogenesis in the ovary and seminal vesicles of earthworms are useful indicators for investigating the endocrine-disrupting property of chemicals. Additionally, our results encourage further studies on developing novel indicators using soil invertebrates to evaluate the effects of the toxicity of endocrine-disrupting chemicals on the soil ecosystem.

Assessing single effects of sugarcane pesticides fipronil and 2,4-D on plants and soil organisms.

The continuous growth in global population since the beginning of the 20th century result in the necessity of food and energy provision favoring the intensive use of agricultural products such as pesticides. Although pesticides are important to prevent losses in the conventional chemically based agriculture, they frequently present side effects, which goes against agricultural production. The use of pesticides cause direct and indirect effects to soil organisms unbalancing essential soil processes (e.g. primary production, organic matter decomposition, nutrient cycling). Under tropical conditions, very little is known regarding the effects of pesticides to terrestrial organisms. Hence, the aim of the present study was to assess the ecotoxicological effects of the herbicide DMA® 806 BR (active ingredient: 2,4-D) and the insecticide Regent® 800 WG (active ingredient: fipronil), on terrestrial plant species (the dicot Raphanus sativus var. acanthioformis and the monocot Allium cepa), and soil invertebrates (the collembolan Folsomia candida and the enchytraeid Enchytraeus crypticus), using natural (NS) and artificial soils (TAS). For both pesticides, negative effects on non-target species were observed at concentrations lower than the doses recommended to prevent pests in sugarcane fields. For both soils, the dicot species was the most affected by the herbicide (R. sativus > A. cepa > F. candida > E. crypticus) and the collembolan species was the most affected by the insecticide (F. candida > E. crypticus = R. sativus = A. cepa). Although the order of the organisms' sensitivity for both pesticides was the same in both soils, results showed that the extent of the effects was soil dependent. Considering the ecologically relevant concentrations tested, and their severe effects to non-target organisms, it may be concluded that the use of fipronil and 2,4-D under recommended conditions may pose a risk to the terrestrial environment.

Oxidative stress in benthic oligochaete worm, Tubifex tubifex induced by sublethal exposure to a cationic surfactant cetylpyridinium chloride and an anionic surfactant sodium dodecyl sulfate.

The present study was assessed to determine the in vivo toxic effects of a cationic surfactant, cetylpyridinium chloride (CPC), and an anionic surfactant, sodium dodecyl sulfate (SDS) in terms of oxidative stress biomarkers in benthic oligochaete worm Tubifex tubifex for 14 days. The investigation demonstrated that sublethal concentrations of CPC (0.0213, and 0.0639 mg L-1) and SDS (1.094 and 3.092 mg L-1)induced paramount alterations in the oxidative stress enzymes in Tubifex tubifex. Superoxide dismutase (SOD), glutathione S-transferase (GST), reduced glutathione (GSH), and glutathione peroxidase (GPx) exhibited an initial notable increase in their activities in the surfactants exposed worms at 1d and 7d of exposure period followed by consequential reduction at 14d exposure period with respect to control, while catalase (CAT) and malondialdehyde (MDA) activities markedly incremented gradually throughout the exposure periods. Through the construction of the correlation matrix and integrated biomarker response (IBR), the effects of CPC and SDS on Tubifex tubifex were distinguished. These results indicate that exposure to these cationic and anionic surfactants modulates the levels of oxidative stress enzymes in Tubifex tubifex.

The migration of cadmium and lead in soil columns and their bioaccumulation in a multi-species soil system.

A soil microcosm experiment was carried out to quantify the transfer of cadmium (Cd) and lead (Pb) in a multi-species soil system (MS·3). Red earth from Jiangxi (S1), fluvo-aquic soil from Henan (S2), fluvo-aquic soil from Beijing (S3), and black soil from Heilongjiang (S4) were used for soil column packing with S1, S3, or S4 as the 20-50 cm layer and S2, which was Cd- and Pb-contaminated, as the top 0-20 cm layer. For each soil combination, four treatments were set up: CK (no wheat and no earthworm), W (only wheat), E (only earthworm), and E + W (earthworm and wheat). The results showed that the coexistence of earthworm with wheat reduced Cd and Pb contents in wheat plants and earthworms, and increased plant biomass, but had no significant effect on the survival rate and mean weight change rate of earthworms. Total Cd and Pb decreased remarkably in the 0-20 cm layer while increased in the 20-50 cm layer, and approximately 32.8%-51.1% of Cd and 0.35%-7.0% of Pb migrated down into the 20-50 cm soil layers from the 0-20 cm soil layers. The migration varied between the treatments from S2 to S1, S2, and S3. In S2-S1 and S2-S4 columns, the amount of Cd migration decreased when the earthworms coexisted with wheat, while in S2-S3 column, there was no significant difference on such amount regardless of the coexistence of earthworms with wheat. Taken together, the results indicated that the migration of Cd and Pb was not only associated with wheat and earthworm, but also depended on soil types.

Study on the regulation of earthworm physiological function under cadmium stress based on a compound mathematical model.

A cadmium (Cd) stress test was carried out on Eisenia fetida in artificial soil. Six Cd concentration gradient solutions (0, 50, 100, 125, 250 and 500 mg/kg) were prepared. Two treatment groups, short-term stress and long-term stress, were established. The former lasted for 10 days, and the latter lasted for 30 days. The Biolog ECO-microplate culture method was used to determine the utilization of the 31 carbon sources by the microbes in earthworm homogenate. The total protein content (TP), peroxidase activity (POD), catalase activity (CAT), superoxide dismutase activity (SOD), glutathione peroxidase activity (GPX), glutathione-S-transferase activity (GST), malondialdehyde content (MDA) and acetylcholinesterase activity (AChE) in earthworm were determined in order to investigate the regulation of oxidative stress and the functional diversity of microbial communities in earthworms under Cd stress. By combining the entropy weight method (EW) and the technique for order preference by similarity to an ideal solution model (TOPSIS), the physiological functional indices of earthworms were assessed objectively and scientifically, and the physiological changes under the different stress periods were evaluated. The results showed that a Cd-tolerant dominant population appeared in the microbial community under Cd stress. In the short-term test, oxidative stress were more effective in coping with Cd stress than the microbial community, and oxidative stress regulated the microbial community functional diversity. Under long-term Cd stress, the regulatory effect was weak or non-existent. In this study, a new evaluation model was established to explore the regulation process of earthworm on its oxidation stress and the functional diversity of microbial communities under Cd stress, and provide a theoretical basis for revealing the detoxification mechanism of earthworms.

Consequences of surface coatings and soil ageing on the toxicity of cadmium telluride quantum dots to the earthworm Eisenia fetida.

The bioaccumulation potential and toxic effects of engineered nanomaterials (ENMs) to earthworms are poorly understood. Two studies were conducted following OECD TG 222 on Eisenia fetida to assess the effects of CdTe QDs with different coatings and soil ageing respectively. Earthworms were exposed to carboxylate (COOH), ammonium (NH4+), or polyethylene glycol (PEG) coated CdTe QDs, or a micron scale (bulk) CdTe material, at nominal concentrations of 50, 500 and 2000 mg CdTe QD kg-1 dry weight (dw) for 28 days in Lufa 2.2 soil. In the fresh soil study, earthworms accumulated similar amounts of Cd and Te in the CdTe-bulk exposures, while the accumulation of Cd was higher than Te during the exposures to CdTe QDs. However, neither the total Cd, nor Te concentrations in the earthworms, were easily explained by the extractable metal fractions in the soil or particle dissolution. There were no effects on survival, but some retardation of growth was observed at the higher doses. Inhibition of Na+/K+-ATPase activity with disturbances to tissue electrolytes, as well as tissue Cu and Mn were observed, but without depletion of total glutathione in the fresh soil experiment. Additionally, juvenile production was the most sensitive endpoint, with estimated nominal EC50 of values >2000, 108, 65, 96 mg CdTe kg-1 for bulk, PEG-, COOH- and NH4+-coated CdTe QDs, respectively. In the aged soil study, the accumulation of Cd and Te was higher than in the fresh soil study in all CdTe QD exposures. Survival of the adult worms was reduced in the top CdTe-COOH and -NH4+ QD exposures by 55 ±â€¯5 and 60 ±â€¯25%, respectively; and with decreases in growth. The nominal EC50 values for juvenile production in the aged soil were 165, 88, 78 and 63 mg CdTe kg-1 for bulk, PEG-, COOH- and NH4+-coated CdTe QDs, respectively. In conclusion, exposure to nanoscale CdTe QDs, regardless of coating, caused more severe toxic effects that the CdTe bulk material and the toxicity increased after soil ageing. There were some coating-mediated effects, likely due to differences in the metal content and behaviour of the materials.

Combined toxicity of imidacloprid and cadmium on histopathology and acetylcholinesterase activity in aquatic oligochaetes (Tubifex tubifex Müller, 1774).

Imidacloprid is one of the neonicotinoid insecticides that has been applied in many farmlands and was detected in many water resources worldwide. However, not only this insecticide but also cadmium was found in the agricultural wastewater in close proximity to industrial areas. This research aims to investigate the acute toxicity of imidacloprid and cadmium on the biochemical changes, pathological changes and accumulation of cadmium in Tubifex tubifex after 24- and 48-h exposure. The results show that combined toxicity of two chemicals was synergistic. In combined toxicity test, cadmium accumulation and acetylcholinesterase activity in worm tissue were significantly increased when compared with the single test. The severity of histopathology shows a dose-dependent relationship. Epidermal and gut cell degeneration, hyperplasia of epidermal and gut cells, irregular surface of the epidermis, overexpression of chloragosome and nerve degeneration were observed. Overall, this research provides useful bio-markers to assess the toxicity of imidacloprid and cadmium on the aquatic environment.

Benzotriazole alleviates copper mediated lysosomal membrane damage and antioxidant defense system responses in earthworms (Eisenia fetida).

Benzotriazole (BTR) is a common corrosion inhibitor used to protect copper (Cu) and Cu alloys. To reveal the combined subacute toxicity of BTR and Cu at environmental levels on terrestrial animals, the activity of antioxidative enzymes and the glutathione levels in earthworms (Eisenia fetida) of the single or co-exposure treatments were determined. The activity of both antioxidant enzymes and non-enzymatic antioxidants was affected by BTR in earthworms. Moreover, the analyses of lysosomal neutral red retention time and total antioxidant capacity indicated a detoxification effect of BTR on Cu-induced impairments of the antioxidant defense capacity in earthworms. The apoptotic rate of coelomocytes in earthworms of the co-exposure treatment was lower than that in earthworms treated with Cu only, indicating that BTR alleviates Cu mediated lysosomal membrane damage and antioxidant defense system responses in earthworms.

Ecotoxicological effects of petroleum-contaminated soil on the earthworm Eisenia fetida.

Petroleum is an important industrial raw material that enters the soil during production and use and is harmful to soil organisms. To evaluate the toxicity of petroleum-contaminated soil, earthworms (Eisenia fetida) were used as model organisms for soil ecotoxicity studies. We found that earthworm weight and cocoon production decreased significantly after exposure to petroleum-contaminated soil. In addition, soil contaminated with high concentrations of petroleum can cause damage to the DNA within earthworm seminal vesicles. Superoxide dismutase (SOD), catalase, and peroxidase activities were significantly inhibited when earthworms were exposed to petroleum-contaminated soil, indicating that oxidative stress was induced by petroleum pollutants. The mRNA levels of annetocin precursor, a reproduction-related gene, was significantly inhibited after petroleum exposure. The mRNA levels of translationally controlled tumour protein (TCTP) and SOD exhibited a concentration-dependent relationship, and their relative expression increased with petroleum concentration.

Ecotoxicological effects of microplastics and cadmium on the earthworm Eisenia foetida.

As microplastics (MPs) have become ubiquitous in both aquatic and terrestrial environments, there has been a growing concern about these new anthropogenic stressors. However, comparatively little is known about the negative effects of MPs, co-contamination of MPs and heavy metals on terrestrial organisms. The objective of this study was performed to understand the adverse effects of exposure to MPs and co-exposure to MPs and cadmium (Cd) on the earthworm Eisenia foetida (E. foetida). Results showed that exposure to MPs only or to a combination of MPs + Cd decreased growth rate and increased the mortality (>300 mg kg-1) after exposure for 42 d, with MPs + Cd (>3000 mg kg-1) posing higher negative influence on the growth of E. foetida. Exposure to MPs might induce oxidative damage in E. foetida, and the presence of Cd accelerates the adverse effects of MPs. Furthermore, the MPs particles can be retained within E. foetida, with values of 4.3-67.2 particles·g-1 earthworm, and can increase the accumulation of Cd in earthworm from 9.7%-161.3%. Collectively, the results of this study demonstrate that combined exposure to MPs and Cd poses higher negative effects on E. foetida, and that MPs have the potential to increase the bioaccessibility of heavy metal ions in the soil environment.