The present study tests the effect of antiparasitic compound ivermectin in a constructed food-web system, a soil multi-species (SMS) higher tier test system. Mutualism, competition and predation within the SMS system were introduced by the addition of five collembolan species, one enchytraeid and a predatory mite species. Bait lamina sticks were incorporated as a measure of functional toxicity, attempting to the integrated feeding activity of the invertebrates. The study showed that on the community level all treatments were significantly affecting the community abundance and composition and that the decrease in abundance corresponded well with increasing exposure concentration for all species. Since all concentrations had significant adverse effect on the community structure, the community-based no-effect-concentration is below the lowest test concentration of 0.25 mg kg⁻¹, whereas the EC10 for the individual species were as low as 0.05 mg kg⁻¹. The bait lamina respond was only affected at the highest exposure concentration.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous analysis of 6 ectoparasiticides – 2 synthetic pyrethroids (deltamethrin, cypermethrin) and 4 macrocyclic lactones (abamectin, doramectin, ivermectin and eprinomectin) in biosolids. The method was used to investigate the occurrence of these ectoparasiticides in beef cattle feedlot wastes in Australia from 5 commercial feedlot operations which employ varying waste management practices. Deltamethrin and cypermethrin were not detected in any of the samples while abamectin, ivermectin, doramectin and eprinomectin were detected in some of the samples with concentrations ranging from 1 to 36 μg/kg dry weight (d.w.) freeze dried feedlot waste. Levels of macrocyclic lactones detected in the feedlot wastes varied and were dependent on sample type. The effect of seasonal variations and waste management practices were also investigated in this study.

At the end of March 2020, ivermectin was confirmed as a drug for COVID-19 treatment. A significant amount of ivermectin could deposit into sediments of the semi-closed Mediterranean Sea, where three European COVID-19 epicenters are located: Italy, Spain, and France. Meiobenthic nematodes were exposed to three ivermectin doses (1.8 ng.g⁻¹, 9 ng.g⁻¹, and 18 ng.g⁻¹) for 10 days. Ivermectin caused a great reduction in abundance. However, the diversity indices decreased only at high doses. Ivermectin disadvantaged the 1B-Cr-Id functional type (non-selective deposit feeders and nematodes with circular or indistinct amphids) and benefited the 2A-REL-Sp type (epistrate feeders and nematodes with rounded or elongated loop amphids). Thus, Trophic Diversity and Amphideal Diversity index values increased with sedimentary ivermectin enrichment. Large amphideal foveas were more efficient for 2A-REL-Sp nematodes to avoid ivermectin. The responses of the functional type 2A-REL-Sp and corresponding taxa predict post-COVID-19 environmental concerns and the bioaccumulation of ivermectin in seafoods.

Anthelmintics (AHs) control animal infections with gastrointestinal nematodes. They reach soil through animal faeces deposited on soils or through manuring. Although soil constitutes a major AH sink, we know little about the mechanisms controlling their soil dissipation. We employed studies with fumigated and non-fumigated soils collected from 12 sheep farms with a variable record of albendazole (ABZ), ivermectin (IVM) and eprinomectin (EPM) use. From each farm, we collected soils from inside small ruminant barn facilities (series A, high exposure) and the associated grazing pastures (series B, low exposure). We asked the following questions: (a) What is the role of soil microorganisms in AH dissipation? (b) Does repeated exposure of soils to AHs lead to their accelerated biodegradation? (c) Which soil physicochemical properties control AH dissipation? Soil fumigation significantly retarded ABZ (DT₅₀ 1.9 and 4.33 days), IVM (34.5 and 108.7 days) and EPM dissipation (30 and 121 days) suggesting a key role of soil microorganisms in AH dissipation. No significant acceleration in AH dissipation was evident in soils from units with a record of the administration of AHs or in soil series A vs series B, suggesting that the level of prior exposure was not adequate to induce their enhanced biodegradation. Significant positive and negative correlations of soil total organic carbon (TOC) and ABZ and IVM dissipation, respectively, were observed. Soil adsorption of AHs increased in the order IVM > ABZ > EPM. TOC controlled soil adsorption of IVM and EPM, but not of ABZ, in support of the contrasting effect of TOC on IVM and ABZ dissipation.

Ivermectin (IVM) is a broad-spectrum antiparasitic drug that is regularly employed in veterinary medicine. In this work, the sorption and desorption of IVM in two Brazilian soils (N1-sand and S2-clay) as well as its leaching capacity, dissipation under aerobic conditions, and degradation in aqueous solution by photocatalysis with TiO₂ in suspension were evaluated. The kinetic sorption curves of IVM were adjusted to a pseudo-second-order model. The sorption and desorption data were well fitted with the Freundlich isotherms in the log form (r > 0.96). The Freundlich sorption coefficient (K F ᵃᵈˢ) and the Freundlich desorption coefficient (K F ᵈᵉˢ) were 77.7 and 120 μg¹⁻¹/ⁿ (cm³)¹/ⁿ g⁻¹ and 74.5 and 138 μg¹⁻¹/ⁿ (cm³)¹/ⁿ g⁻¹, for soils N1 and S2, respectively. A greater leaching capacity of IVM was observed for the sandy soil N1 than for the clay soil S2. Under aerobic conditions, the dissipation (DT₅₀) at 19.3 °C was 15.5 days (soil N1) and 11.5 days (soil S2). Photocatalysis with UVC and TiO₂ in suspension resulted in the degradation of 98 % of IVM (500 μg L⁻¹) in water in 600 s. The toxicity (Daphnia similis) of the solutions submitted to the photocatalytic process was completely eliminated after 10 min.

The surviving insects submitted to chemical control have morphological alterations that impact on their mechanisms of resistance and their final development. Those changes are detected and measured using physical features related to symmetry, specifically named fluctuating asymmetry. This is detected when deviations from the perfect bilateral symmetry for specific morphological characteristic is influenced by genetics or environmental stress. Thus, in this paper we analyze the wing in adult of Culex quinquefasciatus (Diptera - Culicidae) after larvae exposure to ivermectin LC₅₀. Three hundred larvae of C. quinquefasciatus were exposed to ivermectin in 1.5 μg/L (LC₅₀) concentration during 30 min, and three hundred larvae were exposed to distilled pure water as control group. For fluctuating asymmetry, adult males and adult females were selected from each group (n = 83) from the untreated group and (n = 79) from treated group. Wings from adults of each group were mounted in glass microscope slides and coverslip in Canada’s balsam and analyzed with a stereomicroscope with a video camera attached. The treatment effect on M₃ ₊ ₄ was marginally significant with higher asymmetry values in the control group. The data obtained here suggest the importance of future experiments to elucidate the mechanisms associated with FA. Moreover, according to the results obtained, it may be suggested that FA is present in females in ornaments, or secondary sexual characters, as an indicator of phenotypic quality of the partners.

The short-term effects of ivermectin (IVMT) on the oxidative stress and biochemical parameters of Clarias gariepinus juvenile was assessed under semi-static conditions at concentrations of 9 to 25 μg L⁻¹ for up to 4 days. Juveniles were highly sensitive to ivermectin, with an LC₅₀ of 15 μg L⁻¹.The antioxidant enzyme profile assessed included glutathione reductase (GR), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). General stress biomarkers such as serum glucose, protein, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were also determined at 24-h, 48-h, 72-h, and 96-h exposure durations. Lipid peroxidation showed significant (p < 0.05) decreases in higher concentrations (21 μg L⁻¹and 25 μg L⁻¹) and durations of exposure (72 h and 96 h). Significant concentration-dependent increases (p < 0.05) were recorded in the liver function enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) when compared to the control. GPx decreased significantly (p < 0.05) in higher concentrations (21 μg L⁻¹and 25 μg L⁻¹) and durations of exposure (48–96 h). Protein showed significant concentration-dependent decreases, while glucose recorded a mixed trend. The changes in the hepatic antioxidant enzyme activities and serum metabolites were indicative of oxidative stress induced by IVMT. This showed that IVMT is toxic to fish and should be used with utmost caution.