Toxicity of abamectin to the terrestrial isopod Porcellio scaber (Isopoda, Crustacea)

Abamectin-induced behavioral alterations link to energy metabolism disorder and ferroptosis via oxidative stress in Chinese mitten crab, Eriocheir sinensis

The increasing application of abamectin (ABM) in agriculture has raised concerns regarding its environmental safety and potential adverse effects on aquatic environment safety. In the present study, the toxic effects of ABM exposure on the adult Chinese mitten crab, Eriocheir sinensis were investigated, with a focus on locomotion impairment, behavioral changes, oxidative stress, energy metabolism disruption, and ferroptosis. Crabs were exposed to sublethal concentrations of ABM at 2, 20 and 200 μg/L. After 21 d chronic exposure to 200 μg/L, residual ABM in hepatopancreas and muscles were detected as 12.24 ± 6.67 and 8.75 ± 5.42 μg/Kg, respectively. By using acute exposure experiments (96 h), we observed significant locomotion and behavioral alterations, alongside biochemical evidences of oxidative stress and energy metabolism impairment. The presence of ferroptosis, a form of cell death driven by iron-dependent lipid peroxidation, was notably identified in the hepatopancreas. Functional tests with N-acetylcysteine (NAC) supplementation showed restored behavioral responses and decrease of ferroptosis levels. It suggests that mitigating oxidative stress could counteract ABM-induced toxicity. Our findings highlight the critical roles of oxidative stress and ferroptosis in mediating the toxic effects of ABM on E. sinensis, underscoring the need for strategies to mitigate environmental exposure to pesticides.

Terrestrial Biota as Bioindicators for Microplastics and Potentially Toxic Elements

Plastic products used in our daily life remain in the environment for a long time. Plastics decompose gradually into smaller fragments (<5 mm) known as microplastics. There are different sources of microplastics contamination, including plastic bags, masks, synthetic textiles, and various coatings. Microplastics’ smaller size enhances toxic pollutants’ adsorption, through which they are easily digested by small biota and finally accumulated along the food chain. Many studies are found concerning marine microplastic distribution and pollution; however, rarely do they address terrestrial contamination. The terrestrial species Eobania vermiculata, Rumina decollata, Porcellio, Armadillo, Lumbricus terrestris, and Scolopendra were evaluated as bioindicators for soil pollution by microplastics and some potentially toxic metallic elements. Microplastics were isolated with the help of caustic potash. The particles were characterized by infrared spectroscopy (FTIR); some associated potentially toxic metals were assessed in the filtrate by inductively coupled plasma spectrometry (ICP). The following polymers were present in all studied samples: copolyamide, nylon, high- and low-density polyethylene, polyamide, and polyester. In addition, the metallic elements antimony, iron, aluminum, selenium, and zinc were determined with different concentrations. Thus, terrestrial biota can serve as bioindicators for microplastic pollution of soil, which could act as a vector for potentially toxic elements.

Physiological traits of land snails Theba pisana as simple endpoints to assess the exposure to some pollutants

In the current study, the toxicity bioassay of three pollutants abamectin (ABM), thiamethoxam (TMX), and acrylamide (ACR) against land snails Theba pisana was measured. Also, the ecotoxicological effects of dietary exposure to sublethal concentration (1/20 LC₅₀) of these pollutants for 2-week exposure and 1-week recovery on some physiological endpoints evaluated as feeding activity, growth response, and carbonic anhydrase activity as a marker in charge of shell formation and seromucoid level as a marker in charge of mucus synthesis of the snails were studied. The results exhibited that the 48-h LC₅₀ values were 0.91, 313.8, and 45.7 μg/g dry food for ABM, TMX, and ACR, respectively. The sublethal concentrations of these pollutants in the diet after 2-week exposure were found to reduce the food consumption and inhibit growth rate of the snails. Also, the data illustrated that carbonic anhydrase activity was significantly decreased. On the other hand, there was a significant increase in the seromucoid level as a marker responsible for mucus synthesis in ABM- and TMX-exposed snails, while ACR showed significantly decreased level when compared to control. After 1-week recovery, the tested endpoints of treated snails were slightly repaired but still less than that of the untreated animals. The overall outcome of this investigation suggests the utility of this animal as a good bioindicator organism for ABM, TMX, and ACR exposure in pollution monitoring studies.

Use of multiple endpoints to investigate the ecotoxicological effects of abamectin and thiamethoxam on Theba pisana snails

The ecotoxicological effects of dietary exposure to sublethal concentration (1/20 LC₅₀) of abamectin (ABM) and thiamethoxam (TMX) for two weeks exposure and one week recovery on oxidative stress parameters; lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT) and glutathione S-transferase (GST), Deoxyribonucleic acid (DNA) damage as well as immunological parameters; cell death, phagocytosis, lysosomal membrane stability (LMS), lectins, superoxide anion (O₂^-) generation, phenoloxidase (PO), peroxidase (POD) and hemocyanin (Hc) of the land snail, Theba pisana were examined. The results showed that both tested compounds significantly increased DNA damage, LPO content, the activity of CAT and GST, cell death, POD activity, Hc level, whereas, significantly declined in phagocytic activity, LMS, lectins level, O2^- generation, PO activity, and GSH content compared to the controls after two week exposure. After one week of recovery, the measured biochemical parameters of treated snails were slightly repaired but their levels were still less than that of the level of untreated animals. Overall, based on acute toxicity endpoints, ABM appeared to be more harmful than TMX against this animal. Indeed, the different patterns of endpoint responses could represent a useful picture to characterise exposure to these pesticides in the land snail, T. pisana. This battery of snail endpoints might be a promising option to biomonitor the health of the terrestrial ecosystem and to offer valuable insights to the pesticides toxicity mechanisms.

Terrestrial isopods as model organisms in soil ecotoxicology: a review

Isopods play an important role in the decomposition of leaf litter and therefore are making a significant contribution to nutrient cycling and soil ecosystem services. As a consequence, isopods are relevant models in soil ecotoxicology, both in laboratory toxicity tests and in field monitoring and bioindication studies. This paper aims at reviewing the use of isopods as test organisms in soil ecotoxicology. It provides an overview of the use of isopods in laboratory toxicity tests, with special focus on comparing different exposure methods, test durations, and ecotoxicological endpoints. A brief overview of toxicity data suggests that chemicals are more toxic to isopods when exposed through soil compared to food. The potential of isopods to be used in bioindication and biomonitoring is discussed. Based on the overview of toxicity data and test methods, recommendations are given for the use of isopods in standardized laboratory toxicity tests as well as in situ monitoring studies.

Bioaccumulation of hexachlorobenzene in the terrestrial isopod Porcellio scaber

A test system to investigate the biomagnification of organic chemicals in the terrestrial isopod Porcellio scaber was developed and validated. Adult isopods were fed on alder leaf powder (Alnus glutinosa) spiked with [¹⁴ C]hexachlorobenzene (HCB). Test animals, sampled regularly during the uptake (16 d) and depuration phases (16 d), were analyzed, and the kinetics of tissue concentrations were determined. Uptake (k₁ ) and depuration rates (k₂ ) were calculated to estimate kinetic biomagnification factors (BMFs). In addition, the effect of coprophagy on the uptake and accumulation of HCB as well as the tissue distribution of HCB in P. scaber was investigated. The test system was shown to be suitable for investigations into the terrestrial bioaccumulation of chemicals. Coprophagy had no effect on the bioaccumulation of HCB in P. scaber. The hepatopancreas was identified as the main target tissue for HCB accumulation. The low BMF of 0.057 resulted from an assimilation efficiency (α) of 31.42%, a low uptake rate k₁ (0.009 d^-1 ), and a high depuration rate k₂ (0.164 d^-1 ). The results indicate that the terrestrial bioaccumulation of organic chemicals in P. scaber might not represent a worst-case scenario for biomagnification, limiting the value of the test system for the regulatory assessment of organic chemicals. Environ Toxicol Chem 2016;35:2867-2873. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

Avermectin induced inflammation damage in king pigeon brain

To determine the effect of Avermectin (AVM) on inflammation damage in king pigeon brain, eighty two-month-old American king pigeons were randomly divided into four groups, and were fed with either commercial diet or AVM-supplemented diet containing 20 mg kg(-1)diet, 40 mg kg(-1)diet, and 60 mg kg(-1)diet AVM for 30, 60 and 90 d, respectively. Then, the expression level of inflammatory factors (iNOS, PTGEs, NF-κB), histological damage, and ultra-structural damage were examined. It showed that AVM caused higher expressions (P<0.05) of iNOS, PTGEs, NF-κB with disorganized histological and ultra-structural structures in cerebrum, cerebellum, and optic lobe. Meanwhile, inflammatory and histopathological damage were induced by AVM in king pigeon brains. In addition, the main targeted organelle in nervous system was mitochondria, which indicated that mitochondria may be relevant to the process of inflammation induced by AVM. To our best knowledge, this is the first report to study the toxic effect of AVM on inflammatory damage in king pigeon. Thus, the information presented in this study is believed to be helpful in supplementing data for further AVM toxicity study.

Use of scanning electron microscopy to monitor nanofibre/cell interaction in digestive epithelial cells

We provide data obtained by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) on the interaction of ingested tungsten nanofibers with epithelial cells of the digestive tubes of a test organism Porcellio scaber. Conventional toxicity endpoints including feeding behaviour, weight loss and mortality were also measured in each investigated animal. No toxicity was detected in any of exposed animals after 14 days of feeding on tungsten nanofiber dosed food, but when nanofibers enter the digestive system they can react with epithelial cells of the digestive tubes, becoming physically inserted into the cells. In this way, nanofibers can injure the epithelial cells of digestive gland tubes when they are ingested with food. Our SEM data suggest that peristaltic forces may have an important role, not predicted by in vitro experiments, in the interactions of nanomaterials with digestive intestinal cells.

Time-related survival effects of two gluconasturtiin hydrolysis products on the terrestrial isopod Porcellio scaber

Glucosinolates are compounds produced by commercial crops which can hydrolyse in a range of natural toxins that may exert detrimental effects on beneficial soil organisms. This study examined the effects of 2-phenylethyl isothiocyanate and 3-phenylpropionitrile on the survival and growth of the woodlouse Porcellio scaber exposed for 28 d. 2-Phenylethyl isothiocyanate dissipated from the soil with half-lives ranging from 19 to 96 h. Exposure through soil showed toxic effects only on survival. The LC50s after 28 d were significantly different at 65.3 mg kg(-1) for 2-phenylethyl isothiocyanate and 155 mg kg(-1) for 3-phenylpropionitrile. A toxicokinetic-toxicodynamic (TKTD) approach, however, revealed that both compounds in fact have very similar effect patterns. The TKTD model was better suited to interpret the survival data than descriptive dose-response analysis (LC(x)), accounting for the fast dissipation of the compounds in the soil. Found effects were within environmentally relevant concentrations. Care should therefore be taken before allowing these natural toxins to enter soil ecosystems in large quantities.

Soil ecotoxicology: state of the art and future directions

Developments in soil ecotoxicology started with observations on pesticide effects on soil invertebrates in the 1960s. To support the risk assessment of chemicals, in the 1980s and 1990s development of toxicity tests was the main issue, including single species tests and also more realistic test systems like model ecosystems and field tests focusing on structural and functional endpoints. In the mean time, awareness grew about issues like bioavailability and routes of exposure, while biochemical endpoints (biomarkers) were proposed as sensitive and potential early-warning tools. In recent years, interactions between different chemicals (mixture toxicity) and between chemical and other stressors attracted scientific interest. With the development of molecular biology, omics tools are gaining increasing interest, while the ecological relevance of exposure and effects is translating into concepts like (chemical) stress ecology, ecological vulnerability and trait-based approaches. This contribution addresses historical developments and focuses on current issues in soil ecotoxicology. It is concluded that soil ecotoxicological risk assessment would benefit from extending the available battery of toxicity tests by including e.g. isopods, by paying more attention to exposure, bioavailability and toxicokinetics, and by developing more insight into the ecology of soil organisms to support better understanding of exposure and long-term consequences of chemical exposure at the individual, population and community level. Ecotoxicogenomics tools may also be helpful in this, but will require considerable further research before they can be applied in the practice of soil ecotoxicological risk assessment.

Prolonged feeding of terrestrial isopod (Porcellio scaber, Isopoda, Crustacea) on TiO (2) nanoparicles. Absence of toxic effect

Nanoparticles of titanium dioxide are one of most widely used nanomaterials in different products in everyday use and in industry, but very little is known about their effects on non- target cells and tissues. Terrestrial isopods were exposed to food dosed with nano-TiO₂ to give final nominal concentration 1000 and 2000 µg TiO₂/g dry weight of food. The effects of ingested nano-TiO₂ on the model invertebrate Porcellio scaber (Isopoda, Crustacea) after short-term (3 and 7 days) and prolonged (14 and 28 days) dietary exposure was assessed by conventional toxicity measures such as feeding rate, weight change and mortality. Cell membrane destabilization was also investigated. No severe toxicity effects were observed after 3, 7, 14 or 28 days of dietary exposure to nano-TiO₂, but some animals, particularly those exposed to lower concentrations of nanoparticles, had severely destabilized digestive cell membranes. It was concluded that strong destabilization of the cell membrane was sporadic, and neither concentration- nor time-related. Further research is needed to confirm this sporadic toxic effect of nanoparticles.