Exploring the Relationship Among Lipid Profile Changes, Growth, and Reproduction in Folsomia candida Exposed to Teflubenzuron Over Time.

The integration of untargeted lipidomics approaches in ecotoxicology has emerged as a strategy to enhance the comprehensiveness of environmental risk assessment. Although current toxicity tests with soil microarthropods focus on species performance, that is, growth, reproduction, and survival, understanding the mechanisms of toxicity across all levels of biological organization, from molecule to community is essential for informed decision-making. Our study focused on the impacts of sublethal concentrations of the insecticide teflubenzuron on the springtail Folsomia candida. Untargeted lipidomics was applied to link changes in growth, reproduction, and the overall stress response with lipid profile changes over various exposure durations. The accumulation of teflubenzuron in organisms exposed to the highest test concentration (0.035 mg a.s. kg-1 soil dry wt) significantly impacted reproductive output without compromising growth. The results suggested a resource allocation shift from reproduction to size maintenance. This hypothesis was supported by lipid shifts on day 7, at which point reductions in triacylglycerol and diacylglycerol content corresponded with decreased offspring production on day 21. The hypermetabolism of fatty acids and N-acylethanolamines on days 2 and 7 of exposure indicated oxidative stress and inflammation in the animals in response to teflubenzuron bioaccumulation, as measured using high-performance liquid chromatography-tandem mass spectrometry. Overall, the changes in lipid profiles in comparison with phenotypic adverse outcomes highlight the potential of lipid analysis as an early-warning tool for reproductive disturbances caused by pesticides in F. candida. Environ Toxicol Chem 2024;43:1149-1160. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Effects of Life Stage on the Sensitivity of Folsomia candida to Four Pesticides.

The registration of pesticides in the European Union requires the assessment of the toxicity of active substances to soil invertebrates. The most commonly tested soil microarthropod species is Folsomia candida (Collembola), for which toxicity tests usually start with juveniles and determine survival and reproduction after 28 days of exposure, following Organisation for Economic Co-Operation and Development test guideline 232. Test duration may be shortened to 21 days by starting exposures with adult animals. The toxicity of chemicals can, however, vary significantly between different life stages (e.g., juveniles or adults) of the same species. In the present study, we assessed the toxicity of four active substances (cyproconazole, teflubenzuron, imidacloprid, and thiacloprid) to F. candida aged approximately 10 days (juveniles) and 20 days (adults) at the beginning of the tests. Tests were performed in LUFA 2.2 standard soil at 20 ±  2 °C, and effect concentration (ECx) values compared using likelihood ratio tests. The tests lasted 21 days for older springtails and 28 days for the younger ones. Life stage did affect the sensitivity of the springtails, with the survival and reproduction of younger animals being a factor of 2-6.5 more sensitive to the insecticides but not to the fungicide. For teflubenzuron and imidacloprid, the EC50 for younger springtails were 0.025 and 0.111 mg a.s. kg-1 soildw , respectively, and for adults 0.048 and 0.264 mg a.s. kg-1 soildw , respectively. For the younger animals the median lethal concentration values for teflubenzuron, imidacloprid, and thiacloprid were 0.353, 0.224, and 1.02 mg a.s. kg-1 soildw , respectively, and 0.571, 0.446, and 6.91 mg a.s. kg-1 soildw , respectively, for older animals. We discuss the implication of these differences for the risk assessment of pesticides to soil arthropods. Environ Toxicol Chem 2023;42:1782-1790. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Ecotoxicity to Freshwater Organisms and Cytotoxicity of Nanomaterials: Are We Generating Sufficient Data for Their Risk Assessment?

The aim of the present study was to investigate the eco-cytotoxicity of several forms of nanomaterials (NM), such as nano-CuO, nano-TiO2, nano-SiO2 and nano-ZnO, on different aquatic species (Raphidocelis subcapitata, Daphnia magna and Lemna minor) following standard protocols and on human cell lines (Caco-2, SV-80, HepG2 and HaCaT). Predicted no-effect concentrations (PNEC) or hazard concentrations for 5% of the species (HC5) were also estimated based on the compilation of data available in the literature. Most of the NM agglomerated strongly in the selected culture media. For the ecotoxicity assays, nano-CuO and nano-ZnO even in particle agglomeration state were the most toxic NM to the freshwater organisms compared to nano-TiO2 and nano-SiO2. Nano-ZnO was the most toxic NM to R. subcapitata and D. magna, while nano-CuO was found to be very toxic to L. minor. Nano-CuO was very toxic to Caco-2 and HepG2 cells, particularly at the highest tested concentrations, while the other NM showed no toxicity to the different cell lines. The HC5 and PNEC values are still highly protective, due to data limitations. However, the present study provides consistent evidence of the potential risks of both nano-CuO and nano-ZnO against aquatic organisms and also their effects on public health.