Lethal and sublethal effects of acetamiprid on Eisenia andrei: Behavior, reproduction, cytotoxicity and oxidative stress

Effects of neonicotinoid residues on non-target soil animals: A case study of meta-analysis

Neonicotinoids (NEOs) are currently the fastest-growing and most widely used insecticide class worldwide. Increasing evidence suggests that long-term NEO residues in the environment have toxic effects on non-target soil animals. However, few studies have conducted surveys on the effects of NEOs on soil animals, and only few have focused on global systematic reviews or meta-analysis to quantify the effects of NEOs on soil animals. Here, we present a meta-analysis of 2940 observations from 113 field and laboratory studies that investigated the effects of NEOs (at concentrations of 0.001-78,600.000 mg/kg) on different soil animals across five indicators (i.e., survival, growth, behavior, reproduction, and biochemical biomarkers). Furthermore, we quantify the effects of NEOs on different species of soil animals. Results show that NEOs inhibit the survival, growth rate, behavior, and reproduction of soil animals, and alter biochemical biomarkers. Both the survival rate and longevity of individuals decreased by 100 % with NEO residues. The mean values of juvenile survival, cocoon number, and egg hatchability were reduced by 97 %, 100 %, and 84 %, respectively. Both individual and cocoon weights were reduced by 82 %, while the growth rate decreased by 88 % with NEO residues. Our meta-analysis confirms that NEOs pose significant negative impacts on soil animals.

Toxicity evaluation of neonicotinoids to earthworm (Eisenia fetida) behaviors by a novel locomotion tracking assay

Pesticides are substances used for controlling, preventing, and repelling pests in agriculture. Among them, neonicotinoids have become the fastest-growing class of insecticides because of their efficiency in targeting pests. They work by strongly binding to nicotinic acetylcholine receptors (nAChRs) in the central nervous system of insects, leading to receptor blockage, paralysis, and death. Despite their selectivity for insects, these substances may be hazardous to non-target creatures, including earthworms. Although earthworms may be invasive in some regions like north America, they contribute to the development of soil structure, water management, nutrient cycling, pollution remediation, and cultural services, positively impacting the environment, particularly in the soil ecosystem. Thus, this study aimed to develop a novel earthworm behavior assay since behavior is a sensitive marker for toxicity assay, and demonstrated its application in evaluating the toxicity of various neonicotinoids. Here, we exposed Eisenia fetida to 1 and 10 ppb of eight neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram pestanal, thiacloprid, thiametoxam, and sulfoxaflor) for 3 days to observe their behavior toxicities. Overall, all of the neonicotinoids decreased their locomotion, showed by a reduction of average speed by 24.94-68.63% and increment in freezing time movement ratio by 1.51-4.25 times, and altered their movement orientation and complexity, indicated by the decrement in the fractal dimension value by 24-70%. Moreover, some of the neonicotinoids, which were acetamiprid, dinotefuran, imidacloprid, nitenpyram, and sulfoxaflor, could even alter their exploratory behaviors, which was shown by the increment in the time spent in the center area value by 6.94-12.99 times. Furthermore, based on the PCA and heatmap clustering results, thiametoxam was found as the neonicotinoid that possessed the least pronounced behavior toxicity effects among the tested pesticides since these neonicotinoid-treated groups in both concentrations were grouped in the same major cluster with the control group. Finally, molecular docking was also conducted to examine neonicotinoids' possible binding mechanism to Acetylcholine Binding Protein (AChBP), which is responsible for neurotransmission. The molecular docking result confirmed that each of the neonicotinoids has a relatively high binding energy with AChBP, with the lowest binding energy was possessed by thiametoxam, which consistent with its relatively low behavior toxicities. Thus, these molecular docking results might hint at the possible mechanism behind the observed behavior alterations. To sum up, the present study demonstrated that all of the neonicotinoids altered the earthworm behaviors which might be due to their ability to bind with some specific neurotransmitters and the current findings give insights into the toxicities of neonicotinoids to the environment, especially animals in a soil ecosystem.

A multi-biomarker approach to verify chronic effects on Eisenia andrei earthworms exposed to tailings from one of the world's largest mining disasters

Mining is of great relevance to the global economy, but its activities are challenging due to socio-environmental impacts. In January 2019, an iron ore tailings dam collapsed in Brumadinho (Minas Gerais, Brazil) releasing 12 × 106 m3 of tailings, causing human losses and devastation around 3.13 × 106 m2 of a watershed. In this context, the present study aimed to investigate the potential toxic effects of tailings from the collapsed dam using earthworms Eisenia andrei as a model organism for terrestrial environments. An extensive set of tests was performed, including behavioral (avoidance), acute (mortality and biomass) and chronic tests, such as biomass, reproduction and cytotoxicity (viability and cell density and change in coelomocyte pattern). The physical-chemical characterization revealed a higher density of the tailings in relation to the control soil, which can result in physical changes, such as soil compaction and surface sealing. Aluminum, Ca, Fe, Hg, Mg, Mn, K, Na and P registered higher concentrations in the tailings compared to the control soil, while Total Nitrogen, Total Organic Carbon and Organic Matter were higher in the natural soil. Based on the avoidance test, an EC50 of 27.18 ± 2.83% was estimated. No lethality was observed in the acute exposure, nor variations in biomass in the acute and chronic assays. However, there was a tendency to reduce the number of juveniles in relation to cocoons in the proportions of 3125; 12.5 and 25%. Significant changes in viability, cell density and pattern of amebocytes and eleocytes were observed up to the 35th day of exposure. A multi-biomarker approach (Integrated Biological Response version 2) indicated concentration-dependent effects and attenuation of cellular changes over time. These are the first results of chronic effects on earthworms exposed to tailings from the B1 dam. Despite being conclusive, we highlight the possible heterogeneity of the tailings and the necessary care in extrapolating the results.

Biomarker response index in earthworms following chronic exposure to leachate from a closed dumpsite: Behavioral, cytotoxicity and antioxidant system alterations

Leachate, an effluent produced during solid waste decomposition, interacts directly with soil, mainly in dumpsite areas. Studies on terrestrial animal exposure to leachate are, however, lacking. Plants are the most frequently studied organisms, while animal studies, especially earthworms, are limited. Nevertheless, ecotoxicological assessments involving earthworms are crucial due to their role in soil health and ecosystem maintenance, which are paramount in understanding potential terrestrial ecosystem leachate effects. In this context, this study aimed to evaluate behavioral effects, sublethal cytotoxicity and antioxidant system alterations in Eisenia andrei earthworms chronically exposed to leachate from a closed dumpsite. Cytotoxicity was determined by coelomocyte density, viability and cell typing, while antioxidant system alterations were assessed through superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), reduced glutathione (GSH) and metallothionein (MT) determinations. Malondialdehyde (MDA) and protein carbonylation (PTC) levels were also determined as oxidative effect markers. Finally, the Biomarker Response Index (BRI) was assessed, aiming to quantitatively integrate the results of the investigated endpoints and establish a biological health state (BHS) for each leachate concentration. Leachate exposure led to leak responses at concentrations of up to 50%, but attraction at higher concentrations. Decreased cell density (28%) was observed after 48 days and reduced viability (50%), after 14 days of leachate exposure. The observed cell typing changes indicate anti-inflammatory immune system effects. Leachate exposure led to several antioxidant system alterations, increasing SOD (2-6 %), CAT (5-35 %) and GST (5-70 %) activities and GSH (7-37%) and MT (3-67%) levels. Earthworm antioxidant defenses were, however, able to prevent lipid peroxidation, which decreased (11-37%) following leachate exposure to concentrations above 12.5%, and PTC, which increased at 42 days (26%) and reduced at 56 days (12 %). This is the first PTC assessment in leachate-exposed earthworms. The increased carbonylation levels observed after 42 days alongside MDA decreases highlight the need for further research employing oxidative effect biomarkers other than MDA. Finally, an integrated approach employing the BRI was carried out, revealing mild initial changes evolving to moderate to major effects at the highest leachate exposure concentration, with an effect attenuation detected at the end of the experiment. In this sense, this study brings forth a significant novelty, employing a biomarker previously not assessed in earthworms, demonstrating an oxidative effect, alongside the use of the BRI as an integrative tool for the endpoints applied in this assessment.

Toxicological approaches as tool to assess the effects of a mixture of photocatalytic degradation products originated from the unregulated neonicotinoid acetamiprid employing a terrestrial organism (Eisenia andrei)

Acetamiprid (ACT) has been detected in several water sources in Latin America. The presence of its degradation products in the environment is not negligible and transformation products (TPs) significantly contribute to environmental health risks. Although advanced oxidative processes are promising for the treatment of this neocotinoid, effects of these are still unknown. In this context, the effects of a mixture of photocatalytic degradation products resulting from an ACT treatment for 90 min employing TiO2/UV on cytotoxicity and oxidative stress parameters in Eisenia andrei earthworms in acute and chronic experiments using typical Latin American soil were assessed. Acute contact tests were performed (72 h) using a filter paper moistened with an ACT solution and a chronic test was performed using Oxisoil (200 g) moistened with an ACT solution for 45 days. Catalase (CAT) and glutathione-S-transferase (GST) activities, reduced glutathione (GSH) levels and cytotoxicity (cellular eleocyte and amoebocyte assessments) were investigated. Over 75 % of ACT was degraded within the first 15 min of treatment, with levels below the limit of detection after 60 min. The acute test revealed greater cytotoxic effects associated with the effluents treated for T0 and T15 min, with decreased cell density noted after 48 h of exposure, in addition to CAT induction (in all treatments) and GST induction following T0, T15 and T90 min exposures. Concerning the chronic assay, decreases in cell density (T0, T15, T60 and T90 min) and viability (T0, T60 and T90 min) were observed after 45 days, in addition to induced CAT activity following T0, T15 and T60 exposures and GST induction following the T60 min exposure. Reduced glutathione levels were unaltered, comprising the least sensitive biomarker among the investigated parameters to the treated effluent exposures. The mixture of ACT degradation products can cause toxic effects to non-target organisms, despite parent compound degradation, alerting for the need for ecotoxicological tests to prove decreased effluent toxicity, in addition to the improvement of degradation techniques.

The benefit of using in vitro bioassays to screen agricultural samples for oxidative stress: South Africa's case

Applied pesticides end up in non-target environments as complex mixtures. When bioavailable, these chemicals pose a threat to living organisms and can induce oxidative stress (OS). In this article, attention is paid to OS and the physiological role of the antioxidant defense system. South African and international literature was reviewed to provide extensive evidence of pesticide-induced OS in non-target organisms, in vivo and in vitro. Although in vitro approaches are used internationally, South African studies have only used in vivo methods. Considering ethical implications, the authors support the use of in vitro bioassays to screen environmental matrices for their OS potential. Since OS responses are initiated and measurable at lower cellular concentrations compared to other toxicity endpoints, in vitro OS bioassays could be used as an early warning sign for the presence of chemical mixtures in non-target environments. Areas of concern in the country could be identified and prioritized without using animal models. The authors conclude that it will be worthwhile for South Africa to include in vitro OS bioassays as part of a battery of tests to screen environmental matrices for biological effects. This will facilitate the development and implementation of biomonitoring programs to safeguard the South African environment.

Physiological and behavioral assessment of Metaphire posthuma in response to clothianidin insecticide: Insights from molecular and biochemical analysis

In the present study, Clothianidin [(E) - 1-(2 - chloro-1,3 - thiazol - 5-ylmethyl) - 3-methyl - 2- nitroguanidine] (CLO) was selected as a soil pollutant and earthworm was employed as a test organism. The various responses like biochemical and detoxification process of earthworm Metaphire posthuma towards Clothianidin at lethal and sublethal doses were studied using OECD-standardized toxicological guidelines. The present study examined the toxicity of CLO to earthworms after 28 days of exposure at conc. 0, 1.5, 3, 6, 12 and 24 mg kg-1 in a soil mixture. Biochemical markers including Guaiacol peroxidase (POD), Superoxide dismutase (SOD), Catalase (CAT), Glutathione S-transferase (GST) and content of Malondialdehyde (MDA) in earthworms were measured. Acute toxicity tests revealed that CLO caused a concentration-dependent increase in mortality with LC50 (Lethal concentration) values of 10.960 and 8.201 mg kg-1 for 7th and 14th day respectively. The earthworms were exposed to CLO contaminated soil for 56 days and reflecting the significant decrease in earthworm growth, cocoon and hatchling production. Moreover, enzyme activities such as CAT, SOD, POD and MDA content were significantly enhanced with the increased concentration and exposure period of CLO. Molecular docking studies indicated that CLO primarily interacts to the junction site of SOD and in active centres of CAT, POD and GST. As a result, the current findings imply that the sub chronic CLO exposure can induce variations in physiology and avoidance behaviour of earthworms, oxidative stress as well as alterations in enzyme activities.

An integrated approach to evaluate acetamiprid-induced oxidative damage to tRNA in human cells based on oxidized nucleotide and tRNA profiling

Acetamiprid is poisonous to mammals due to severe acetamiprid-induced oxidative stress that could cause mitochondrial dysfunctions, lipid and protein oxidation, inflammation, apoptosis, and DNA damage. Evidence has accumulated for the role of oxidative stress in changing structures and functions of transfer RNAs (tRNAs) by inducing tRNA cleavage, reprogramming tRNA modifications and impairing aminoacyl-tRNA synthetase editing sites. However, the impact of acetamiprid-induced oxidative stress on tRNA is still unknown. Here, we investigated the effects of acetamiprid on cell viability, reactive oxygen species (ROS) levels, DNA damage, cellular oxidized nucleotide concentrations, and oxidative damage to tRNA in HepG2 cells and LO2 cells. Acetamiprid can cause the significant increment of ROS and DNA oxidative damage. In this study, an integrated approach was established to simultaneously study the network of oxidized nucleotides and explore the tRNA oxidative damage after acetamiprid exposure. A simple and high-throughput liquid chromatography with tandem mass spectrometry (LC-MS/MS) method coupled with (trimethylsilyl)diazomethane (TMSD) derivatization was successfully developed to quantify 12 cellular oxidized nucleotides that cannot be detected using traditional detection methods because of the huge interferences from naturally abundant nucleotides. Meanwhile, the accumulation rate and the locating sites of 8-oxo-2, 7-dihydro-guanine (8-oxo-G) in tRNA were inspected using the established N-(tert-Butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) labeling-based tRNA profiling method. After acetamiprid treatment, the increment of oxidized nucleoside triphosphates is smaller than that of their corresponding mono- and diphosphates, as well as the dephosphorylated nucleosides, on account of the existence of sanitization enzymes. Several tRNA fragments, CUC[m1A]Gp, CACGp, [Cm]C[m2G]p, and DDGp, are significantly downregulated in acetamiprid-treated HepG2 cells, while only [Cm]C[m2G]p in acetamiprid-treated LO2 cells. According to the profiling results, the significantly changed fragment CUC[m1A]Gp might be caused by the oxidation of guanine (G) to form 8-oxo-G at position 15 in human tRNAphe([Gm]AA), providing more information about the effect of oxidized nucleobases on tRNA's functions.

Chlorine substitution-dependent toxicities of polychlorinated biphenyls to the earthworm Eisenia fetida in soil

Polychlorinated biphenyls (PCBs) with different chlorine substitution patterns often coexist in e-waste-processing sites. However, the single and combined toxicity of PCBs to soil organisms and the influence of chlorine substitution patterns remain largely unknown. Herein, we evaluated the distinct in vivo toxicity of PCB28 (a trichlorinated PCB), PCB52 (a tetrachlorinated PCB), PCB101 (a pentachlorinated PCB), and their mixture to earthworm Eisenia fetida in soil, and looked into the underlining mechanisms in an in vitro test using coelomocytes. After a 28-days exposure, all PCBs (up to 10 mg/kg) were not fatal to earthworms, but could induce intestinal histopathological changes and microbial community alterations in the drilosphere system, along with a significant weight loss. Notably, pentachlorinated PCBs with a low bioaccumulation ability showed greater inhibitory effects on the growth of earthworm than lowly chlorinated PCBs, suggesting that bioaccumulation was not the main determinant of chlorine substitution-dependent toxicity. Furthermore, in vitro assays showed that the highly chlorinated PCBs induced a high-percentage apoptosis of eleocytes in the coelomocytes and significantly activated antioxidant enzymes, indicating that the distinct cellular vulnerability to lowly/highly chlorinated PCBs was the main contributor to the PCBs toxicity. These findings emphasize the specific advantage of using earthworms in the control of lowly chlorinated PCBs in soil due to their high tolerance and accumulation ability.

Effects of a Neonicotinoid on Indigenous Earthworm Perionyx excavatus Biochemical and Histopathological Alterations

Acetamiprid is a broad-spectrum insecticide, belonging to the neonicotinoid compounds group, which has been extensively applied throughout the globe. Recently, indiscriminate use of these compounds was reported to cause fatal impacts on non-targeted soil organisms. Hence, the present study aimed to examine the impact of acetamiprid on Indian indigenous earthworm, Perionyx excavatus. Acute toxicity revealed an LC₅₀ concentration of 0.25 µg/cm² for filter paper test/72 h and 400 µg/kg for artificial soil test/14 days. Oxidative stress (ROS) and various biomarkers including superoxide dismutase, catalase, glutathione S-transferase, malondialdehyde content and DNA damage were measured. The results of the biomarker responses confirmed the acetamiprid exposure can cause toxicity to P. excavatus. In addition, cell density (20 × 10² cell mL/mg) and cell viability (40%) were significantly (p < 0.05) reduced. Further, the ecotoxicological assessment made through this study can be utilized as good evidence to toxicity of neonicotinoids to non-targeted indigenous organisms.

Biodegradation of neonicotinoid insecticide acetamiprid by earthworm gut bacteria Brucella intermedium PDB13 and its ecotoxicity

Extensive use of neonicotinoid insecticides in recent decade had contaminated water and soil systems and poses serious environmental and health risk. Microbial degradation of toxic contaminants in the environment has been established as a sustainable tool towards its remediation. Under this context, the present study focused on the biodegradation of neonicotinoid insecticide acetamiprid, by bacterial strain Brucella intermedia PDB13 isolated from the gut of the acetamiprid exposed earthworms. To enhance acetamiprid biodegradation, suitable parameters such as pH, temperature, inoculum size and acetamiprid concentration range were optimised using Response Surface Methodology (RSM). The experimental results showed that the Brucella intermedium PDB13 can tolerate and degrade relatively high concentrations of acetamiprid (50 - 350 mg L^-1). The results confirmed that maximum degradation of about 89.72% was achieved under optimized conditions. Further, confirmation of acetamiprid biodegradation was assessed through the occurrence of its degraded metabolites through HPLC, FTIR, and LCMS analysis. Based on this analysis, possible acetamiprid biodegradation pathway by Brucella intermedia PDB13 was proposed. Additionally, cytotoxicity, earthworm acute toxicity, and zebrafish embryo toxicity studies were also performed to assess the toxicity variations between the parent compound and its metabolites. The acetamiprid treated group resulted in cytotoxic effects apparently, with the increase in aberrant cells frequency (22.5 ± 3.3), when compared with its metabolites (2.3 ± 4.3) and control (1.9 ± 5.6) respectively. All these results evidently reported the degradation potential of Brucella intermedia PDB13, thereby establishing the scope for further advanced biodegradation studies towards mitigating the pesticide pollution.

The sulfoximine insecticide sulfoxaflor exposure reduces the survival status and disrupts the intestinal metabolism of the honeybee Apis mellifera

Honeybees (Apis mellifera) are indispensable pollinators in agricultural production, biodiversity conservation, and nutrients provision. The abundance and diversity of honeybees have been rapidly diminishing, possibly related to the extensive use of insecticides in ecosystems. Sulfoxaflor is a novel sulfoximine insecticide that, like neonicotinoids, acts as a competitive modulator of nicotinic acetylcholine receptors (nAChR) in insects. However, few studies have addressed the negative effects of sulfoxaflor on honeybees at environmentally relevant concentrations. In the present study, adult workers were fed a 50% (w/v) of sugar solution containing different concentrations (0, 0.05, 0.5 and 2.0 mg/L) of sulfoxaflor for two weeks consecutively. The survival rates, food intake, and body weight of the honeybees significantly decreased after continuous exposure at higher doses (0.5 and 2.0 mg/L) of sulfoxaflor when compared with the control. The change in the metabolites in the honeybee gut was determined using high-throughput non-targeted metabolomics on day 14 after sulfoxaflor treatment. The results revealed that 24 and 105 metabolites changed after exposure to 0.5 and 2.0 mg/L sulfoxaflor, respectively, compared with that of the control groups. A total of 12 changed compounds including pregenolone and glutathione were detected as potential biomarkers, which were eventually found to be enriched in pathways of the steroid hormone biosynthesis (p = 0.0001) and glutathione metabolism (p = 0.021). These findings provide a new perspective on the physiological influence of sulfoxaflor stress in honeybees.

Metsulfuron-methyl induced physiological, behavioural and biochemical changes in exotic (Eisenia fetida) and indigenous (Metaphire posthuma) earthworm species: Toxicity and molecular docking studies

In modern agricultural practices, Metsulfuron-methyl (sulfonylurea herbicide) is widely employed to inhibit the weeds and grasses. The current study revealed that Metaphire posthuma was more sensitive than Eisenia fetida against Metsulfuron-methyl (MSM). The LC₅₀ values for Eisenia fetida were 2884.08 mgkg^-1 and 1871.18 mgkg^-1after 7 and 14 days, respectively. Similarly, the LC₅₀ values for Metaphire posthuma were 2449.34 mgkg^-1 and 1673.10 mgkg^-1for 7 and 14 days, respectively. Reproduction parameters were significantly decreased at 400 (T3), 800 (T4) and 1600 (T5) mgkg^-1 MSM in E. fetida whereas at 200 (T2), 400 (T3), 800 (T4), 1600 (T5) mgkg^-1 MSM in M. posthuma. EC₅₀ of avoidance response for 20% MSM by E. fetida and M. posthuma was recorded 901.76 mgkg^-1and 544.21 mgkg^-1 respectively. Malondialdehyde (MDA) content along with guaiacol peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD) activities were initially increased up to 21st day by MSM, inducing a slight oxidative stress in earthworms and recovered to control level on 28th day. The GST activities were continuously stimulated throughout the exposure period and enhance the detoxification effect thereby preventing the earthworms from toxins. Molecular docking studies indicated that hydrogen bonding and hydrophobic interactions are key forces in binding between MSM and SOD/CAT/POD/GST. As a result, this is the first study to be reported on physiological, behavioural and biochemical changes in two different earthworm species under the exposure of sulfonyl urea herbicide.

Enantiomer-Specific Study of Fenpropathrin in Soil-Earthworm Microcosms: Enantioselective Bioactivity, Bioaccumulation, and Toxicity

In this study, the enantiomer-specific bioactivity, bioaccumulation, and toxicity of fenpropathrin (FEN) enantiomers were investigated in soil-earthworm microcosms. The bioactivity order was S-FEN > rac-FEN > R-FEN for Spodoptera litura and Conogethes punctiferalis. Moreover, S-FEN was 12.0 and 32.2 times more toxic than rac-FEN and R-FEN to earthworms, respectively. S-FEN degraded faster than R-FEN with the enrichment of R-FEN in the soil environment. Furthermore, the peak-shaped accumulation curves for FEN enantiomers were observed, and R-FEN was preferentially bioaccumulated by earthworms. As compared to R-FEN, S-FEN induced greater changes in the activities of detoxification enzymes, antioxidant enzymes, and malondialdehyde content, which suggested that earthworms exhibited enantioselective defense responses to S-FEN and R-FEN. Integrated biomarker response results indicated that S-FEN exhibited higher toxic effects on earthworms than R-FEN. Finally, molecular simulation revealed that the greater interaction forces between S-FEN and sodium channel protein could be the primary reason for the enantioselective bioactivity and toxicity of FEN enantiomers. This study comprehensively highlights the enantiomer-specific bioactivity, bioaccumulation, toxicity, and mechanism of FEN in soil-earthworm microcosms at the enantiomer level. Our findings will contribute to a better risk assessment of FEN in the soil ecosystem.

Ecotoxicological responses of Daphnia magna and Eisenia andrei in landfill leachate

Leachate toxicity using bioindicators such as microcrustaceans and earthworms has not been fully elucidated. These bioindicators are traditionally determined through physicochemical and microbiological analyses. The ecotoxicological assessment of leachate using indicator organisms from different environments is a technique to ensure the treatment and safe disposal of this effluent with minimum impact on human health and the environment. The current study aimed to evaluate the ecotoxicological responses of Daphnia magna and Eisenia andrei in landfill leachate, identifying which organism was more sensitive to this effluent. The leachate used in ecotoxicological tests was collected at the Campina Grande Sanitary Landfill (ASCG), Paraíba, Brazil. The leachate sample contained a high content of organic matter in the form of chemical oxygen demand (19496.86 mg.L^-1) and ammoniacal nitrogen (2198.00 mg.NL^-1), in addition to metals with carcinogenic potential, such as Cr (0.64 mg.L^-1) and Fe (1.16 mg.L^-1). The exposure of Daphnia magna to the leachate showed that the effluent is harmful to aquatic organisms, obtaining an EC 50, 48 h = 1.22%, FT of 128 and a TU of 81.96%. Among the contaminant concentrations tested in Eisenia andrei, 57% (59.28 mL.kg^-1) caused the highest lethality, causing the death of 21 earthworms within 72 hours of exposure. The avoidance test showed that exposure to leachate concentrations between 10.38 and 39.86 mL.kg^-1 led to the leakage of earthworms, and habitat loss was observed at a concentration of 55.80 mL.kg^-1, in which leak response (LR) ≥80% was obtained. This study demonstrates that the mentioned organisms are suitable for ecotoxicological tests in landfill leachate. Moreover, the microcrustacean Daphnia magna showed the most significant sensitivity, presenting a rapid ecotoxicological response to the leachate.

Long-Term Exposure to Neonicotinoid Insecticide Acetamiprid at Environmentally Relevant Concentrations Impairs Endocrine Functions in Zebrafish: Bioaccumulation, Feminization, and Transgenerational Effects

Neonicotinoid insecticides have attracted worldwide attention due to their ubiquitous occurrence and detrimental effects on aquatic organisms, yet their impacts on fish reproduction during long-term exposure remain unknown. Here, zebrafish (F0) were exposed to a neonicotinoid, acetamiprid, at 0.19-1637 μg/L for 154 d. Accumulation and biotransformation of acetamiprid were observed in adult fish, and the parent compound and its metabolite (acetamiprid-N-desmethyl) were transferred to their offspring. Acetamiprid caused slight survival reduction and significant feminization in F0 fish even at the lowest concentration. Hormone levels in F0 fish were remarkedly altered, that is, gonad 17β-estradiol (E2) significantly increased, while androstenedione decreased. The corresponding transcription of steroidogenic genes (ar, cyp19b, fshβ, gnrh2, gnrh3, and lhβ) were significantly upregulated in the brain and gonad of the females but downregulated in the males. The vtg1 gene expression in the liver of male fish was also upregulated. In addition to F0 fish, parental exposure to acetamiprid decreased hatchability and enhanced malformation of F1 embryos. Chronic exposure to acetamiprid at environmentally relevant concentrations altered hormone production and the related gene expression of the hypothalamic-pituitary-gonad (HPG) axis in a sex-dependent way, caused feminization and reproductive dysfunction in zebrafish, and impaired production and development of their offspring.

Determination of Acetamiprid Residues in Vegetables by Indirect Competitive Chemiluminescence Enzyme Immunoassay

Acetamiprid (ACE) is widely used in various vegetables to control pests, resulting in residues and posing a threat to human health. For the rapid detection of ACE residues in vegetables, an indirect competitive chemiluminescence enzyme immunoassay (ic-CLEIA) was established. The optimized experimental parameters were as follows: the concentrations of coating antigen (ACE-BSA) and anti-ACE monoclonal antibody were 0.4 and 0.6 µg/mL, respectively; the pre-incubation time of anti-ACE monoclonal antibody and ACE (sample) solution was 30 min; the dilution ratio of goat anti-mouse-HRP antibody was 1:2500; and the reaction time of chemiluminescence was 20 min. The half-maximum inhibition concentration (IC₅₀), the detection range (IC₁₀–IC₉₀), and the detection limit (LOD, IC₁₀) of the ic-CLEIA were 10.24, 0.70–96.31, and 0.70 ng/mL, respectively. The cross-reactivity rates of four neonicotinoid structural analogues (nitenpyram, thiacloprid, thiamethoxam, and clothianidin) were all less than 10%, showing good specificity. The average recovery rates in Chinese cabbage and cucumber were 82.7–112.2%, with the coefficient of variation (CV) lower than 9.19%, which was highly correlated with the results of high-performance liquid chromatography (HPLC). The established ic-CLEIA has the advantages of simple pretreatment and detection process, good sensitivity and accuracy, and can meet the needs of rapid screening of ACE residues in vegetables.

Effects of polyethylene, polyvinyl chloride, and polystyrene microplastics on the vermitoxicity of fluoranthene in soil

Polycyclic aromatic hydrocarbons (PAHs) and microplastics (MPs) may coexist in soil. Consequently, the toxicity of PAHs to "soil engineers" earthworms (vermitoxicity), may be influenced by various MPs. However, studies on this issue are scarce. In particular, the differential effect of MPs of different polymers on the vermitoxicity of PAHs remains unclear. Therefore, a series of microcosm experiments were conducted to evaluate the potential vermitoxicity of fluoranthene (Fla) in the presence of polyethylene (PE), polyvinyl chloride (PVC), and polystyrene (PS) MPs at an environmentally relevant concentration (125 mg kg^-1). The results indicated that Fla exerted vermitoxicity and MPs enhanced the adverse effects. Specifically, after the introduction of MPs, the 14-d LC₅₀s of Fla on earthworms decreased from 130.9 to 98.0-123.6 mg kg^-1; in addition, the growth inhibition rates improved from 5.37%-15.34% to 15.63%-33.38%, and the avoidance rate increased by 10%-100% at the same exposure doses in most cases. In most cases, the neutral red retention time was shortened by 14.3%-47.9%, indicating that the integrity of the coelomocytes' lysosomal membrane had worsened. The affected antioxidant enzyme activity and improved malondialdehyde content indicated enhanced oxidative damage in the treatments containing MPs. However, the aggravation of the vermitoxicity varied by MPs type and toxicological endpoints. Overall, Fla + PS MPs exerted the greatest effect on the mortality of earthworms. On the contrary, PVC and PE MPs exhibited higher subacute effects on the vermitoxicity of Fla. Our study also demonstrated that MPs at environmentally relevant doses may directly induce vermitoxicity. In particular, damaged coelomocytes' lysosomal membrane stability by MPs was second reported to the best of our knowledge. Our results revealed the differences in the effects of various MPs on the vermitoxicity of PAHs, which provides new data in assessing the ecological effects of PAHs and MPs in soils.

Different cellular mechanism of imidacloprid and acetamiprid by a combined targeted lipidomics and metabolomics approach in Neuro-2a cells

As commonly used neonicotinoid insecticides for pest control, imidacloprid (IMI) and acetamiprid (ACE) posed neurotoxicity effects on living organisms. However, researches of the differences in toxicity mechanism between these two neonicotinoid insecticides are still limited. In this study, different cellular metabolism perturbations and redox homeostasis damages induced by IMI and ACE exposure in Neuro-2a cells were investigated. Distinct elevation of lactate dehydrogenase (LDH) activity and caspase 7 level demonstrated the influences on necrosis and apoptosis. There were 21 and 12 metabolites screened out as potential biomarkers after IMI and ACE exposure, including lipids and amino acids. Remarkable decrease of lipid hydroperoxides (LOOH) and increase of reactive oxygen species (ROS) generation were found only in the ACE20 group. Interference with glutathione metabolism pathway was further validated by detecting GPx (glutathion peroxidase), GSH (reduced glutathione) and GSSG (oxidized glutathione) levels. Taken together, the metabolic interferences and oxidative damages in ACE20 group were significantly different from the other three exposure groups. These results help to explore the toxicity mechanism of neonicotinoid insecticides from multiple perspectives. This study provides scientific basis for evaluating toxicity of different neonicotinoid insecticides.

Behavioral, histopathological, genetic, and organism-wide responses to phenanthrene-induced oxidative stress in Eisenia fetida earthworms in natural soil microcosms

Phenanthrene (PHE) contamination not only changes the quality of soil environment but also threatens to the soil organisms. There is lack of focus on the eco-toxicity potential of this contaminant in real soil in the current investigation. Here, we assessed the toxic effects of PHE on earthworms (Eisenia fetida) in natural soil matrix. PHE exhibited a relatively high toxicity to E. fetida in natural soil, with the LC₅₀ determined to be 56.68 mg kg^-1 after a 14-day exposure. Excessive ROS induced by PHE, leading to oxidative damage to biomacromolecules in E. fetida, including lipid peroxidation, protein carbonylation, and DNA damage. The antioxidant defense system (total antioxidant capacity, glutathione S-transferase, peroxidase, catalase, carboxylesterase, and superoxide dismutase) in E. fetida responded quickly to scavenge excess ROS and free radicals. Exposure to PHE resulted in earthworm avoidance responses (2.5 mg kg^-1) and habitat function loss (10 mg kg^-1). Histological observations indicated that the intestine, body wall, and seminal vesicle in E. fetida were severely damaged after exposure to high-dose PHE. Moreover, earthworm growth (weight change) and reproduction (cocoon production and the number of juvenile) were also inhibited after exposure to this pollutant. Furthermore, the integrated toxicity of PHE toward E. fetida at different doses and exposure times was assessed by the integrated biomarker response (IBR), which confirmed that PHE is more toxic to earthworms in the high-dose and long-term exposure groups. Our results showed that PHE exposure induced oxidative stress, disturbed antioxidant defense system, and caused oxidative damage in E. fetida. These effects can trigger behavior changes and damage histological structure, finally cause growth inhibition, genotoxicity, and reproductive toxicity in earthworms. The strength of this study is the comprehensive toxicity evaluation of PHE to earthworms and highlights the need to investigate the eco-toxicity potential of exogenous environmental pollutants in a real soil environment.

Antioxidant system alterations and biological health status of earthworms following long-term exposure to antibiotic-contaminated poultry litter

Poultry litter is widely applied as a fertilizer even though it is one of the main antibiotic sources to agricultural soils. Long-term sublethal effects (56 days) on the antioxidant system of Eisenia andrei earthworms following exposure to fluoroquinolone-contaminated poultry litter (enrofloxacin + ciprofloxacin) at 5.0, 10, and 20 g kg^-1 were evaluated. The following biomarkers were assessed: superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), reduced glutathione (GSH), and a lipid peroxidation (LPO) proxy. Significant CAT and SOD increases, and a moderate positive correlation (ρ = 0.67, p < 0.05) between these enzymes was observed. Glutathione-S-transferase levels increased significantly at 10 g kg^-1, while GSH exhibited a dose-dependent response at 5.0 mg kg^-1 (4-106%), 10 mg kg^-1 (28-330 %), and 20 mg kg^-1 (45-472%). LPO levels exhibited a decreasing trend with increasing poultry litter concentrations of 8-170% (5.0 g kg^-1), 7-104% (10 mg kg^-1), and 3-6% (20 mg kg^-1). A principal component analysis (PCA) highlighted increased SOD and CAT activities, possibly due to increased reactive oxygen species (ROS) concentrations. Biological health status assessments based on the biomarker response index indicate major alterations in the first month of exposure and becoming moderate in the second month. These findings indicate an antioxidant system attenuation trend. It is possible, however, that successive poultry litter applications may reduce the long-term recovery capacity of the evaluated biomarkers.

Statement on the active substance acetamiprid

Acetamiprid is a pesticide active substance with insecticidal action currently under the third renewal (AIR3) of the Commission implementing regulation (EU) No 844/2012. Following concerns that this substance may pose high risks to humans and the environment, the French authorities asked the Commission to restrict its uses under Article 69 of Regulation (EC) No 1107/2009. To support this request, competent Authorities from France cited a series of literature papers investigating its hazards and/or exposure to humans and the environment. Consequently, the EFSA PPR Panel was mandated to advise on the likelihood that body of evidence would constitute proof of serious risks to humans or the environment. Therefore, the EFSA PPR Panel evaluated the likelihood of these studies indicating new or higher hazards and exposure to humans and the environment compared to previous EU assessments.A stepwise methodology was designed, including: (i) the initial screening; (ii) the data extraction and critical appraisal based on the principles of OHAT/NTP; (iii) the weight of evidence, including consideration of the previous EU assessments; (iv) the uncertainty analysis, followed, whenever relevant, by an expert knowledge elicitation process. For human health, no conclusive evidence of higher hazards compared to previous assessment was found for genotoxicity, developmental toxicity, neurotoxicity including developmental neurotoxicity and immunotoxicity. However, due to the lack of adequate assessment of the current data set, the PPR Panel recommends conducting an assessment of endocrine disrupting properties for acetamiprid in line with EFSA/ECHA guidance document for the identification of endocrine disruptors. For environment, no conclusive, robust evidence of higher hazards compared to the previous assessment was found for birds, aquatic organisms, bees and soil organisms. However, the potential of high inter-species sensitivity of birds and bees towards acetamiprid requires further consideration.

Long-term landfill leachate exposure modulates antioxidant responses and causes cyto-genotoxic effects in Eisenia andrei earthworms

It is estimated that approximately 0.4% of the total leachate produced in a landfill is destined for treatment plants, while the rest can reach the soil and groundwater. In this context, this study aimed to perform leachate toxicity evaluations through immune system cytotoxic assessments, genotoxic (comet assay) appraisals and antioxidant system (superoxide dismutase - SOD; catalase - CAT, glutathione-S-transferase - GST; reduced glutathione - GSH and metallothionein - MT) evaluations in Eisenia andrei earthworms exposed to a Brazilian leachate for 77 days. The leachate sample contained high organic matter (COD - 10,630 mg L^-1) and ammoniacal nitrogen (2398 mg L^-1), as well as several metals, including Ca, Cr, Fe, Mg, Ni and Zn. Leachate exposure resulted in SOD activity alterations and increased CAT activity and MT levels. Decreased GST activity and GSH levels were also observed. Antioxidant system alterations due to leachate exposure led to increased malondialdehyde levels as a result of lipid peroxidation after the 77 day-exposure. An inflammatory process was also observed in exposed earthworms, evidenced by increased amoebocyte density, and DNA damage was also noted. This study demonstrates for the first time that sublethal effect assessments in leachate-exposed earthworms comprise an important tool for solid waste management.

Integrated non-targeted lipidomics and metabolomics analyses for fluctuations of neonicotinoids imidacloprid and acetamiprid on Neuro-2a cells

Neonicotinoid insecticides are widely used for pest control. However, they are highly water-soluble and easily ingested by organisms, posing potential health risks. In this study, cytotoxicity evaluations of imidacloprid and acetamiprid were conducted in Neuro-2a cells by obtaining their half maximal inhibitory concentration (IC₅₀ values) (1152.1 and 936.5 μM, respectively). The toxic effects at the IC₁₀ and IC₂₀ on cell metabolism were determined by integrated non-targeted lipidomics and metabolomics analyses. Changes in the concentration of acetamiprid caused the most drastic perturbations of metabolism in Neuro-2a cells. Altogether, the detected lipids were mainly attributed to triglyceride, phosphatidylcholine (PC), and diglyceride. These three categories of lipids accounted for more than 67% of the sum in Neuro-2a cells. A total of 14 lipids and other 40 metabolites were screened as differential metabolites based on multivariate data analysis, and PCs were most frequently observed with a proportion of 25.9%. The results demonstrated that lipid metabolism should be paid considerable attention after imidacloprid and acetamiprid exposure. Pathway analysis showed that the metabolisms of glycerophospholipid, sphingolipid, and glutathione were the dominant pathways that were interfered. The present study is the first to investigate the cellular toxic mechanisms after separate imidacloprid and acetamiprid exposure by using lipidomics and metabolomics simultaneously. This research also provides novel insights into the evaluation of the ecological risk of imidacloprid and acetamiprid and contribute to the study of toxicity mechanism of these neonicotinoid insecticides to animals and humans in the future.

Low concentration acetamiprid-induced oxidative stress hinders the growth and development of silkworm posterior silk glands

Acetamiprid is a new type of nicotinic insecticide that is widely used in pest control. Its environmental residues may cause silkworm cocooning disorder. In this study, silkworms that received continuous feeding of low concentration acetamiprid (0.15 mg/L) showed significantly decreased silk gland index and cocooning rate. Gene expression profiling of posterior silk glands (PSGs) revealed that the differentially expressed genes were significantly enriched in oxidative stress-related signal pathways with significant up-regulation. The contents of both H₂O₂ and MDA were increased, along with significantly elevated SOD and CAT activities, all of which reached maximal values at 48 h when H₂O₂ and MDA's contents were 10.46 and 7.98 nmol/mgprot, respectively, and SOD and CAT activities were 5.51 U/mgprot and 33.48 U/gprot, respectively. The transcription levels of antioxidant enzyme-related genes SOD, Mn-SOD, CuZn-SOD, CAT, TPX and GPX were all up-regulated, indicating that exposure to low concentration acetamiprid led to antioxidant response in silkworm PSG. The key genes in the FoxO/CncC/Keap1 signaling pathway that regulates antioxidant enzyme activity, FoxO, CncC, Keap1, NQO1, HO-1 and sMaf were all up-regulated during the whole process of treatment, with maximal values being reached at 72 h with 2.91, 1.46, 1.82, 2.52, 2.32 and 4.01 times of increases, respectively. These results demonstrate that exposure to low concentration acetamiprid causes oxidative stress in silkworm PSG, which may be the cause of cocooning disorder in silkworm. Our study provides a reference for the safety evaluation of environmental residues of acetamiprid on non-target insects.

Sublethal and lethal effects of the imidacloprid on the metabolic characteristics based on high-throughput non-targeted metabolomics in Aphis gossypii Glover

Sublethal effect considered as an emerging factor to assess the environmental risk of insecticides, which can impact the insects on both physiology and behavior. Lethal exposure can be causing near immediate mortality. Pests are inevitably exposed to sublethal and lethal dose in the agroecosystem following application of pesticides. Insecticides, widely used for the control of insect pests, are irreplaceable in insect pest management. The effects of imidacloprid by the method of high-throughput non-targeted metabolomics was investigated in Aphis gossypii Glover exposed to LC₁₀ and LC₉₀ doses of the imidacloprid, and the control group was treated with the same condition without imidacloprid. Pairwise comparisons showed that 111 metabolites changed significantly, 60 in the LC₁₀ group, and 66 in the LC₉₀ group compared to the control group, while only 16 changes in the LC₁₀ were same with that in LC₉₀ group. Among the changed metabolites, a total of 16 metabolites were identified as potential biomarkers, which represented the most influential pathways including glycolysis and gluconeogenesis, alanine, aspartate, and glutamate metabolism, ascorbate and aldarate metabolism, glutathione metabolism, phenylalanine metabolism, tyrosine metabolism, caffeine metabolism and parkinson's disease (PD), which could account for the sublethal and lethal effects on A. gossypii. These modified metabolic pathways demonstrated that high energy consumption, excitotoxicity and oxidative stress (OS) were appeared in both LC₁₀ and LC₉₀ groups, while PD was detected only in the LC₉₀ group. The results of non-targeted metabolomics revealed the effects of neonicotinoid pesticide exposure on A. gossypii successfully, and provided a deep insight into the influenced physiology by the stress of neonicotinoid pesticide in the insect.

Ecotoxicological evaluation of imazalil transformation products on Eisenia Andrei

Data concerning the toxicity of the transformation products of some pesticides considered emerging contaminants are still incipient. This study aimed to evaluate acute (filter paper contact and avoidance test) and chronic (assays carried out in Red yellow Ultisoil) effects of the transformation products of the fungicide imazalil (IMZ) by heterogeneous photocatalysis (TiO₂/UV) in Eisenia andrei. Some endpoints, i.e. biomass variation, disorder in reproduction and avoidance behavior, cytotoxicity (cell density and feasibility), and coelomic fluid (eleocytes and amoebocytes, immune cell) and antioxidant system (catalase (CAT) and glutathione S-transferase (GST)) changes were assessed. The studied degradation times (6, 18, 35 and 90 min) represented 70; 35; 10 and 0% of the initial IMZ concentration (5 mg L^-1). No lethality and no significant difference in biomass variations were noted in the acute contact test. Decreased GST and increased CAT activities, as well as cell typing alterations and decreased cell viability and density detected at the 90-min degradation timepoint (PDT-90) indicate direct cytotoxic IMZ transformation product effects. In the avoidance test, no significant earthworm repulsion or attraction was observed. PDT-90 transformation products were responsible for losses in biomass and a reduction in the number of earthworm cocoons and juveniles present in soil. No cytotoxic effects were observed in the long term, although increased CAT and decreased GST activities were observed. Investigations on the relative toxicity of IMZ transformation products are relevant for future discussions regarding the environmental treatment, control and destination of this compound and its derivatives.

Fluoroquinolone-contaminated poultry litter strongly affects earthworms as verified through lethal and sub-lethal evaluations

Poultry litter is one of the main sources of fluoroquinolones (FQs) in agricultural soils. In this study, our main goal was to investigate FQ-contaminated poultry litter effects on Eisenia andrei earthworms. To achieve this, acute and chronic tests covered several endpoints, such as avoidance, biomass, lethality, reproduction and changes to immune cells. FQs (enrofloxacin and ciprofloxacin) were determined in a poultry litter sample through high performance liquid chromatography with a fluorescence detector. The avoidance test indicates that poultry litter strongly repels earthworms, even at the lowest concentration (50 g kg^-1). In the acute test, the lethal concentration of poultry litter to 50% of the earthworms (LC₅₀), was estimated at 28.5 g kg^-1 and a significant biomass loss (p < 0.05) occurred at 40 g kg^-1. In the chronic test, a significant reproduction effect was observed at 20 g kg^-1. Cell typing, density and feasibility indicated significant effects ranging from 5 to 20 g kg^-1. A high risk quotient was estimated based on recommended poultry litter applications in field studies. Although FQ contamination in poultry litter and soils has been widely reported in previous studies, this is, to the best of our knowledge, the first toxicological assessment concerning earthworms exposed to FQ-contaminated poultry litter.

Triclocarban affects earthworms during long-term exposure: Behavior, cytotoxicity, oxidative stress and genotoxicity assessments

Triclocarban (TCC) is a contaminant of emerging concern widely applied as an antimicrobial in personal care products and introduced into the terrestrial environment through the application of biosolids (i.e., treated sewage sludge) in agriculture. Displaying the potential to bioaccumulate in the food chain and a high half-life in the soil, the presence of this compound in the environment may lead to potential ecological risks. In this context, TCC toxicity assessments in Eisenia andrei earthworms were carried out through acute, avoidance and chronic tests following cytotoxicity, antioxidant system, i.e. acatalase (CAT), glutathione-S-transferase (GST), glutathione (GSH), lipid peroxidation (LPO), and DNA damage (comet assay) evaluations. An LC₅₀ of 3.3 ± 1.6 mg cm^-2 in the acute contact test and an EC₅₀ of 1.92 ± 0.31 mg kg^-1 in the avoidance test during 72 h and 48 h, respectively, were obtained. The behavioral test indicates earthworm avoidance from 15.0 mg kg^-1 of TCC. During chronic soil exposure, a 44% reduction in earthworm cell viability was observed after 14 days of exposure to 10 mg kg^-1 TCC, while an increase in the percentage of amoebocyte cells also ocurred. Chronic exposure to TCC led to reduced CAT and GST activities, decreased GSH levels and increased LPO in exposed organisms. DNA damage was observed after 45 days from a 1 mg kg^-1 dose of TCC. Therefore, TCC exhibits toxicological potential to Eisenia andrei earthworms, mainly during long-term exposures. This study provides mechanistic earthworm information towards understanding the environmental and human health implications of TCC exposure and draws attention to correct biosolid management.

The mechanism of damage to the posterior silk gland by trace amounts of acetamiprid in the silkworm, Bombyx mori

Acetamiprid is a new neonicotinoid insecticide widely used in the prevention and control of pests in agriculture. However, its residues in the environment affect the cocooning of the silkworm, Bombyx mori (B. mori), a non-target insect. To investigate the mechanism of damage, B. mori larvae were fed with trace amounts of acetamiprid (0.15 mg/L). At 96 h after exposure, the larvae showed signs of poisoning and decreased body weight, resulting in reduced survival and ratio of cocoon shell. At 48 h and 96 h after exposure, the residues in the posterior silk gland (PSG), which is responsible for synthesizing silk fibroin, were 0.72 μg/mg and 1.21 μg/mg, respectively, as measured by high performance liquid chromatography, indicating that acetamiprid can accumulate in the PSG. Moreover, pathological sections and transmission electron microscopy also demonstrate the damage of the PSG by acetamiprid. Digital gene expression (DGE) and KEGG pathway enrichment analysis revealed that genes related to metabolism, stress responses and inflammation were significantly up-regulated after exposure. Quantitative RT-PCR analysis showed that the transcript levels of FMBP-1 and FTZ-F1 (transcription factors for synthesizing silk protein) were up-regulated by 2.55-and 1.56-fold, respectively, and the transcript levels of fibroin heavy chain (Fib-H), fibroin light chain (Fib-L), P25, Bmsage and Bmdimm were down-regulated by 0.75-, 0.76-, 0.65-, 0.44- and 0.40-fold, respectively. The results indicate that accumulated acetamiprid causes damage to the PSG and leads to reduced expression of genes responsible for synthesizing silk fibroin. Our data provide reference for evaluating the safety of acetamiprid residues in the environment for non-target insects.

Occurrence, source and ecotoxicological risk assessment of pesticides in surface water of Wujin District (northwest of Taihu Lake), China

This study investigated the occurrence and distribution of pesticides in surface water (lakes, major rivers and tributaries) and potential discharge sources (fish ponds, livestock and poultry farms, and sewage treatment plants) in Wujin District (northwest of Taihu Lake), Jiangsu province, China. An analytical liquid chromatography-tandem mass spectrometry method was developed for 38 pesticides, which was applied in the monitoring of 240 surface water samples and 76 potential discharge source samples. Eleven insecticides and five fungicides with temporal and spatial variation were detected in surface water. The total pesticide concentrations in surface water in different seasons were as follows: March > August > June > November. The two most polluting and widespread pesticides were carbendazim (maximum concentration 508 ng L^-1, detection rate 100%) and imidacloprid (maximum concentration 438 ng L^-1, detection rate 88%). Gehu Lake (S46) and Sanshangang River (S12) were seriously polluted water bodies. Seven insecticides and four fungicides were detected in the potential discharge sources; and their composition changed significantly with the seasons. The concentrations of detected organophosphorus pesticides and neonicotinoids (e.g. acetamiprid in March and dichlorvos in November) in a few non-agricultural planting sources were far greater than those detected in surface water, and hence a few fish ponds, livestock and poultry farms, and sewage treatment plants might be the potential discharge sources of pesticides in the surrounding surface water. The estimated input flux of the studied pesticides from upstream rivers to Taihu Lake was 141.95 kg a^-1. Furthermore, more attention should be paid to the medium or high aquatic ecotoxicological risk presented by the levels of organophosphorus pesticides, carbamates, and benzimidazoles.

Evaluating Earthworms’ Potential for Remediating Soils Contaminated with Olive Mill Waste Sediments

The olive-oil industry generates large amounts of residues that, in the past, were accumulated in evaporating ponds in many Mediterranean countries. Currently, these open-air ponds pose a serious environmental hazard because of toxic chemicals that concentrate in their sediments. Bioremediation of olive mill waste (OMW) sediments has emerged as a viable option for managing this environmentally problematic residue. Here, we postulate that inoculation of an OMW-soil mixture with earthworms may be a complementary bioremediation strategy to that using native microorganisms only. A laboratory study assessed the ecotoxicity of OMW-amended soils (10%, 20%, 40% and 80% w/w) combining earthworm biomarker responses and soil enzyme activities. The doses of 40% and 80% were toxic to earthworms, as evidenced by the high mortality rate, loss of body weight and signs of oxidative stress after 30 d of soil incubation. Conversely, doses ≤ 20% w/w were compatible with earthworm activity, as indicated by the significant increase of soil enzyme activities. Total concentrations of phenolic compounds decreased by more than 70% respect to initial concentrations in 10% and 20% OMW treatments. These results suggest that OMW sediments intentionally mixed with soils in an up to 20% proportion is a workable bioremediation strategy, where earthworms can be inoculated to facilitate the OMW degradation.

Neonicotinoids: Spreading, Translocation and Aquatic Toxicity

Various environmental and ecotoxicological aspects related to applications of neonicotinoid insecticides are assessed. Dosages of neonicotinoids applied in seed coating materials were determined and are compared to other applications (spray and granule). Environmental levels in soils and affecting factors in translocation are discussed. Excretion of neonicotinoids via guttation from coated maize seeds up to two months upon emergence, as well as cross-contamination of plants emerged from non-coated seeds or weeds nearby have been demonstrated. Contamination of surface waters is discussed in scope of a worldwide review and the environmental fate of the neonicotinoid active ingredients and the formulating surfactant appeared to be mutually affected by each other. Toxicity of neonicotinoid active ingredients and formulations on Daphnia magna completed with some investigations of activity of the detoxifying glutathione S-transferase enzyme demonstrated the modified toxicity due to the formulating agents. Electrophysiological results on identified central neurons of the terrestrial snail Helixpomatia showed acetylcholine antagonist (inhibitory) effects of neonicotinoid insecticide products, but no agonist (ACh-like) effects were recorded. These data also suggested different molecular targets (nicotinergic acetylcholine receptors and acetylcholine esterase enzyme) of neonicotinoids in the snail central nervous system.

Novel electrochemical aptasensor with dual signal amplification strategy for detection of acetamiprid

In this work, a novel dual signal amplification strategy for aptasensor employing reduced graphene with silver nanoparticles and prussian blue-gold nanocomposites was developed for detection of acetamiprid. To improve the sensitivity of aptasensors, reduced graphene oxide-silver nanoparticles (rGo-AgNPs) were modified on a bare glassy carbon electrode surface, which provided a large specific surface area for subsequent material immobilization and amplified current signal. The electrical signal output and sensitivity of the aptasensor was significantly improved after the immobilization of prussian blue-gold nanoparticles (PB-AuNPs) as a catalyst for the redox reaction. The analysis experiment exhibited that it had super-high sensitivity with a detection limit of 0.30 pM (S/N = 3), which met the requirements of the vast majority of daily leaf vegetable testing. Under optimized conditions, the proposed aptasensor showed a wide linear detection range from 1 pM to 1 μM. This aptasensor also had good stability and high selectivity for acetamiprid detection without an interfering effect of some other pesticides. The proposed aptasensor displayed good recovery rates in real samples, which proposed a new method for constructing electrochemical sensors and provided a novel tool for rapid, sensitive analysis of pesticides with low cost.