Effects of single and combined exposures to copper and benzotriazole on Eisenia fetida

Occurrence of traffic related trace elements and organic micropollutants in tunnel wash water

Substantially polluted tunnel wash water (TWW) is produced during road tunnel maintenance. Previous literature has reported the presence of trace elements and polycyclic aromatic hydrocarbons (PAHs). However, it was hypothesized that other organic pollutants are present, and more knowledge is needed to prevent environmental harm. This study reveals for the first time the presence of four short- and 17 long-chained per- and polyfluoroalkyl substances (PFASs), three benzothiazoles (BTHs), six benzotriazoles (BTRs), four bisphenols, and four benzophenones in TWW from a Norwegian road tunnel over a period of three years. Concentrations of PAHs, PFASs, BTHs, and BTRs were higher than previously reported in e.g., road runoff and municipal wastewater. Trace elements and PAHs were largely particulate matter associated, while PFASs, BTHs, BTRs, bisphenols, and benzophenones were predominantly dissolved. 26 of the determined contaminants were classified as persistent, mobile, and toxic (PMT) and are of special concern. It was recommended that regulations for TWW quality should be expanded to include PMT contaminants (such as PFPeA, PFBS, BTR, and 4-OH-BzP) and markers of pollution (like 2-M-BTH, 2-OH-BTH, and 2-S-BTH from tire wear particles). These findings highlight the need to treat TWW before discharge into the environment, addressing both, particulate matter associated and dissolved contaminants.

Copper toxicity on Eisenia fetida in a vineyard soil: a combined study with standard tests, genotoxicity assessment and gut metagenomic analysis

Copper (Cu) toxicity is a pressing concern for several soils, especially in organic viticulture. The objective of this work was to assess Cu toxicity on the non-target organism Eisenia fetida, employing both traditional and novel tools for early identification of Cu-induced damages. In addition to traditional tests like avoidance and reproductive toxicity experiments, other tests such as the single cell gel electrophoresis (SCGE) and gut microbiome analysis were evaluated to identify early and more sensitive pollution biomarkers. Four sub-lethal Cu concentrations were studied, and the results showed strong dose-dependent responses by the earthworm avoidance test and the exceeding of habitat threshold limit at the higher Cu doses. An inverse proportionality was observed between reproductive output and soil Cu concentration. Bioaccumulation was not detected in earthworms; soil concentrations of potentially bioavailable Cu were not affected by E. fetida presence or by time. On the contrary, the SCGE test revealed dose-dependent genotoxicity for the 'tail length' parameter already at the second day of Cu exposition. Gut microbiome analysis a modulation of microbial composition, with the most aboundant families being Pectobateriaceae, Comamonadaceae and Microscillaceae. Bacillaceae increased over time and showed adaptability to copper up to 165 mg/kg, while at the highest dose even the sensitive Acetobacteriaceae family was affected. The research provided new insights into the ecotoxicity of Cu sub-lethal doses highlighting both alterations at earthworms' cellular level and changes in their gut microbiota.

Combined pollution effects of Cu and benzotriazole in rice (Oryza sativa L.) verified by split-root experiment

Although the combined effect of organic ligands and heavy metals in the environment on plants have been frequently reported, their complexed interaction in plants and the physiological effects remain to be revealed. Metal complexing agent benzotriazole (BTR) has extensive environmental pollution. In this study, root-splitting experiments were designed to identify the in vivo and in vitro effects of BTR on the accumulation and translocation of Cu in rice (Oryza sativa L.), and the concentrations and translocation factor (TF) of Cu and BTR in different parts of rice were measured. In the in vitro interaction treatments, low BTR concentrations enhanced Cu uptake and lateral transport in rice, while higher levels of BTR's exposure (i.e., ≥ 100 μM) resulted in opposite effects. Differently, significant increase in the lateral transport of Cu and vertical translocation of BTR in rice presented in the in vivo interaction treatments. TF of Cu from root A to root B (TFRA-RB) increased from 0.05 to 0.272 with the BTR concentration increasing from 0 to 100 μM, and higher TF of BTR from root to shoot (TFR-S), ranging from 1.00 to 1.75, compared with single BTR exposure treatments was observed. The phytotoxicity of BTR expressed by the catalase activity was significantly alleviated by the in vivo accumulated Cu in rice.

Multi-omics analysis reveals copper-induced growth inhibition mechanisms of earthworm (Eisenia fetida)

Exposure to high concentrations of copper can cause toxic effects on the growth and development of organisms, but the relevant toxic mechanisms are far from fully understood. This study investigated the changes of metabolites, genes, and gut microorganisms in earthworms (Eisenia fetida) exposed to 0 (control), 67.58 (low), 168.96 (medium), and 337.92 (high) mg/kg of Cu in soil for 60 days. Differentially expressed genes (DEGs) and differential metabolites (DMs) at the low-, medium-, and high-level Cu exposure groups were identified and introduced into Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Integrated metabolomic and transcriptomic analysis revealed that amino acid metabolism, lipid metabolism, and carbohydrate metabolism are the major metabolic pathways disturbed by Cu exposure. Furthermore, Cu exposure significantly decreased the diversity of the intestinal bacterial community and affected the relative abundance (increased or decreased) of intestinal colonizing bacteria. This resulted in high energy expenditure, inhibited nutrient absorption and fatty acid synthesis, and weakened antioxidant and detoxification abilities, ultimately inhibiting the growth of E. fetida. These findings offer important clues and evidence for understanding the mechanism of Cu-induced growth and development toxicity in E. fetida and provide further data for risk assessment in terrestrial ecosystems.

Mechanisms, toxicity and optimal conditions - research on the removal of benzotriazoles from water using Wolffia arrhiza

In the presented work, phytoremediation with the use of floating plant Wolffia arrhiza (L.) Horkel ex Wimm. was proposed as a method of removing the selected benzotriazoles (BTRs): 1H-benzotriazole (1H-BTR), 4-methyl-1H-benzotriazole (4M-BTR), 5-methyl-1H-benzotriazole (5M-BTR) and 5-chlorobenzotriazole (5Cl-BTR) from water. The efficiency of phytoremediation depends on three factors: daily time of exposure to light, pH of the model solution, and the amount of plans. Using a design of experiment (DoE) methods the following optimal values were selected: plant amount 1.8 g, light exposure 13 h and pH 7 per 100 mL of the model solution. It was found that the loss of BTRs in optimal conditions ranged from 92 to 100 % except for 4M-BTR, for which only 23 % of removal was achieved after 14 days of cultivation of W. arrhiza. The half-life values for studied compounds ranged from 0.98 days for 5Cl-BTR to 36.19 for 4M-BTR. The observed rapid vanishing of 5M-BTR is supposed by the simultaneous transformation of 5M-BTR into 4M-BTR. The detailed study of BTRs degradation pointed that the plant uptake is mainly responsible for the benzotriazoles concentration decrease. Toxicity tests showed that the tested organic compounds induce oxidative stress in W. arrhiza, which manifested among others, in reduced levels of chlorophyll in cultures with benzotriazoles compared to control.

Integration of transcriptomic and metabolomic reveals metabolic pathway alteration in earthworms (Eisenia fetida) under copper exposure

Copper is a trace element that necessary for plant growth in the soil. However, in recent years, due to human activities, the content of copper in soil exceeds the standard seriously, which is threatening the safety of soil animals, plants and even human beings. In this study, we investigated the effects and molecular mechanisms of 60 days long-term copper exposure on earthworms (Eisenia fetida) at 67.58 mg/kg, 168.96 mg/kg and 337.92 mg/kg concentration by using transcriptome and metabolomics. Transcriptome analysis showed that the expression of energy metabolism related genes (LDH, GYS, ATP6N, GAPDH, COX17), immune system related genes (E3.2.1.14) and detoxification related genes (UGT, CYP2U1, CYP1A1) were down-regulated, the expression of antioxidant system related genes (GCLC, HPGDS) were up-regulated in copper exposure experiment of earthworms. Similarly, metabolomics analysis revealed that the expression of energy metabolism related metabolites (Glucose-1-phosphate, Glucose-6-phosphate), TCA cycle related metabolites (fumaric acid, allantoic acid, malate, malic acid) were down-regulated, digestion and immune system related metabolites (Trehalose-6-phosphate) were up-regulated. Integrating transcriptome and metabolomics data, it was found that higher antioxidant capacity and accelerated TCA cycle metabolism may be an adaptive strategy for earthworms to adapt to long-term copper stress. Collectively, the results of this study will greatly contribute to incrementally understand the stress responses on copper exposure to earthworms and supply molecular level support for evaluating the environmental effects of copper on soil organisms.

Effect of copper on bioconcentration of benzotriazole ultraviolet stabilizers (BUVSs) in common carp (Cyprinus carpio)

Benzotriazole ultraviolet stabilizers (BUVSs) have received increasing attention as emerging contaminants. However, most of the existing relevant studies focused on the adverse ecological effect of BUVSs under their single exposure, information about the bioconcentration potential of BUVSs and their joint exposure with heavy metals remains scarce. In this study, we investigated the bioconcentration kinetics of 6 frequently reported BUVSs in four main tissues of common carp under different Cu concentration. The bioconcentration factors (BCFs) and half-lives (t_1/2) in the fish tissues ranged from 5.73 (UV-PS in kidney) to 1076 (UV-327 in liver), and 2.19 (UV-PS in kidney) to 31.5 (UV-320 in liver) days, respectively. Under the effect of Cu, an increase in BCF values was observed, which is mainly due to the decreased depuration rate (k₂). These results indicated that BUVSs accumulated in fish and that Cu can affect the bioconcentration of BUVSs. This study provides important insight into the co-exposure of heavy metal and BUVSs, contributing to the perfection of BUVSs risk assessment.

The Recolonization Concentration Concept: Using Avoidance Assays with Soil Organisms to Predict the Recolonization Potential of Contaminated Sites

In this study the recolonization concentration concept for soil organisms is presented and validated. This concept is based on the empirically deduced avoidance–recolonization hypothesis, which shows a negative correlation between avoidance (AC_x) and recolonization (RC_x) (AC_x = RC_100−x) responses. The concept was validated in a two-step approach composed by (i) individual placement tests, to demonstrate the non-influence of individual placement in a dual chamber avoidance test and (ii) small scale gradient tests to demonstrate that the number of colonizers reaching a soil patch with a certain concentration is independent on their previous exposure to lower concentrations. Overall, data show that avoidance data can be used, when framed under the recolonization concentration concept, to evaluate the recolonization potential of contaminated sites. The recolonization concept is an important theoretical concept that when coupled with spatial modelling tools could be used to tackle the spatial and temporal recovery dynamics of contaminated soil.

Sub-lethal effects of soil multiple contamination on the avoidance behaviour of Eisenia fetida

Natural ecosystems are frequently exposed to complex mixtures of different chemicals. However, the environmental risk assessment is mainly based on data from individual substances. In this study, the individual and combined effects on the terrestrial earthworm E. fetida exposed to the anionic surfactant sodium lauryl ether sulphate (SLES) and the pesticides chlorpyrifos (CPF) and imidacloprid (IMI) were investigated, by using the avoidance behaviour as endpoint. Earthworms were exposed to a soil artificially contaminated with five sub-lethal concentrations of each contaminant, both as single substances and in combination of binary and ternary mixtures. Overall results showed that IMI provoked the highest avoidance effect on earthworms, with a concentration value that induced an avoidance rate of 50% of treated organisms (AC50) of 1.30 mg/kg, followed by CPF (AC50 75.26 mg/kg) and SLES (AC50 139.67 mg/kg). The application of the Combination Index (CI) method, indicated that a deviation from the additive response occurred for most of the tested chemical mixtures, leading to synergistic or antagonistic avoidance responses. Synergistic effects were produced by the exposure to the two lowest concentrations of the CPF+IMI mixture, and by the highest concentrations of SLES+CPF and SLES+CPF+IMI mixtures. On the contrary, antagonistic effects were observed at the lowest concentrations of the binary mixtures containing the SLES and at almost all the tested concentrations of the SLES+CPF+IMI mixture (with the exception of the highest tested concentration). These results show that the avoidance test is suitable to assess the detrimental effects exerted on earthworms by chemical mixtures in soil ecosystems and the use of behavioural endpoints can increase the ecological significance of environmental risk assessment procedures.

Insights into the mechanisms underlying the remediation potential of earthworms in contaminated soil: A critical review of research progress and prospects

In recent years, soil pollution is a major global concern drawing worldwide attention. Earthworms can resist high concentrations of soil pollutants and play a vital role in removing them effectively. Vermiremediation, using earthworms to remove contaminants from soil or help to degrade non-recyclable chemicals, is proved to be an alternative, low-cost technology for treating contaminated soil. However, knowledge about the mechanisms and framework of the vermiremediation various organic and inorganic contaminants is still limited. Therefore, we reviewed the research progress of effects of soil contaminants on earthworms and potential of earthworm used for remediation soil contaminated with heavy metals, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), pesticides, as well as crude oil. Especially, the possible processes, mechanisms, advantages and limitations, and how to boost the efficiency of vermiremediation are well addressed in this review. Finally, future prospects of vermiremediation soil contamination are listed to promote further studies and application of vermiremediation in contaminated soils.

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.

Toxic effects of new ethyl-carbamates on the morphology, mortality and acetylcholinesterase activity of Eisenia foetida

The toxicity of the ixodicidal carbamates ethyl-4-bromophenyl carbamate (LQM 919), ethyl-4-chlorophenyl carbamate (LQM 996) and propoxur on Eisenia foetida adults was evaluated to estimate their ecotoxic potential. The earthworm mortality and weight loss produced by the three evaluated carbamates showed a concentration-dependent effect (p < 0.0001) in the contact filter paper test (CFPT). In the artificial soil test (AST), mortality increased in relation to the exposure time (p < 0.0001) and the concentration (p < 0.01) of the carbamates. Only the earthworms exposed in the CFPT showed morphological alterations. According to the LC₅₀ obtained in the CFPT, the three carbamates were classified as very toxic and, according to the LC₅₀ obtained in the AST, the three carbamates were classified as highly toxic for E. foetida. The values of k_i and k_d indicated that LQM 919 and LQM 996 are weak inhibitors with lower affinity for the acetylcholinesterase of E. foetida than that of propoxur. The concentrations in the CFPT and AST at which 100% mortality was observed in E. foetida were 64- and 4-fold higher, respectively, than the egg hatching inhibitory concentration 99% reported for ticks.

Growth inhibition and fate of benzotriazoles in Chlorella sorokiniana cultures

Benzotriazoles are among the most commonly found organic micropollutants in the aquatic environment. In this study, toxicity experiments were conducted in order to investigate the effects of different benzotriazoles on Chlorella sorokiniana growth. Four compounds were tested; 1H-benzotriazole (BTR), xylytriazole (XTR), 5-methyl-1H-benzotriazole (5TTR) and 5-chlorobenzotriazole (CBTR). The fate of these micropollutants was also studied under batch conditions and the effect of different mechanisms on their elimination was investigated. According to the results, the EC₅₀ values in single-substance toxicity experiments were calculated to 8.3 mg L^-1 for BTR, 22 mg L^-1 for 5TTR and 38.7 mg L^-1 for CBTR. A slight inhibition on microalgae growth was noted at the maximum tested concentration of XTR (77 mg L^-1), while no inhibition was observed when a mixture of target BTRs was tested at 200 μg L^-1. Calculation of the Risk Quotient (RQ) showed no possible ecological threat in the presence of 5TTR, XTR and CBTR, while RQ values close or higher than 1 were estimated for BTR. All target contaminants were significantly eliminated in microalgae experiments that lasted 16 days. Their removal efficiency ranged between 42.2 ± 3.1% (XTR) to 97.2 ± 0.9% (XTR), while their half-life values were estimated to 2.4 ± 0.5 days for 5TTR, 6.5 ± 0.6 days for BTR, 15.2 ± 1.4 days for CBTR and 20.7 ± 2.0 days for XTR. Photodegradation was the main mechanism affecting BTR, XTR and CBTR removal, while bioremoval processes enhanced 5TTR elimination. The addition of sodium acetate decreased the removal efficiency of BTRs possibly due to catabolite repression. This is the first study investigating the toxicity and fate of BTRs in microalgae cultures.

Occurrence, toxicity and transformation of six typical benzotriazoles in the environment: A review

Benzotriazoles (BTs) are a group of heterocyclic compounds which have been widely applied in industrial activities and domestic life mainly as corrosive inhibitors. BTs have been ubiquitously detected in receiving environments and cause potential toxicity to non-target organisms. This paper reviews the occurrence and fate of six selected benzotriazole compounds in different environmental and biological matrices, as well as the transformation and toxicity. Due to their high hydrophilicity and insufficient removal in wastewater treatment plants (WWTPs), these compounds were widely detected in aquatic environments with concentrations mainly from tens ng/L to tens μg/L. Considerable residual levels of BTs in plant, fish, air, tap water and human urine have implied the potential risks to various organsims. The reported acute toxicity of BTs are generally low (EC₅₀ in mg/L level). Some observed sublethal effects including endocrine disrupting effects, hepatotoxicity and neurotoxicity, as well as the ability to promote the development of endometrial carcinoma still raise a concern. BTs are found often more recalcitrant to biodegradation compared to photolysis and ozonation. Environmental factors including pH, temperature, irradiation wavelength, redox condition as well as components of matrix are proved crucial to the removal of BTs. Further studies are needed to explore the precise environment fate and toxicity mechanism of BTs, and develop advanced treatment technologies to reduce the potential ecological risks of BTs.

Effects of benzotriazole on copper accumulation and toxicity in earthworm (Eisenia fetida)

Triazole contaminants in water and soil environments can form complexes with metal ions, and therefore affect the bioavailability and toxicity of some heavy metals. In present study, significant increase of copper (Cu) uptake by earthworm (Eisenia fetida) was observed when combined pollution of benzotriazole (BTR) presented in soil. For instance, Cu accumulation in earthworms increased 55% approximately when BTR presented at the BTR/Cu molar ratio of 1:2.5. While the single Cu exposure (at 32 mg kg^-1 in soil) resulted in increased malondialdehyde (MDA) content in earthworms from 0.319 to 0.668 nmol mg protein^-1, joint exposure to BTR at BTR/Cu molar ratio of 1:10 significantly decreased the MDA content to 0.405 nmol mg protein^-1. This indicates a potential detoxification effect of BTR to Cu induced oxidative damage in earthworms. Varied Cu subcellular distribution can be observed in earthworms of the single and combined exposure treatments. With the combined exposure of BTR, the proportion of Cu associated with granular fraction, the toxically inert fraction in earthworms, increased from 25% to 39%. This phenomenon can be used to explain the protective effects of BTR against oxidative damage.