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Type II pyrethroids, chemical structures and their action, toxicity of Pyrethroids
Source publication
Pesticides are the biological toxicants which are required by man to kill insects, pests and also man's fight against the spread of diseases. Now pesticides usage became an indispensible and integral part of world agriculture. Modern agriculture practices even though contributed to enhance crop production but also widely polluted aquatic environmen...
Context in source publication
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Context: Insects are a major threat to crop production. They can infect, damage, and reduce agricultural yields. Accurate and fast detection of insects will help insect control. From a computer algorithm point of view, insect detection from imagery is a tiny object detection problem. Handling detection of tiny objects in large datasets is challengi...
Citations
... As a result, the entire fertilization process, from sperm motility to embryonic development, can be directly affected by excess contaminants, such as pesticide residues leached from the soil by rain, or even by inadequate disposal of containers and residues (Kime & Nash 1999, Ferreira 2016. These contaminants greatly influence the reproduction and renewal of fish species stocks, which can lead to an environmental imbalance and a reduction in species diversity (Mondal et al. 2015). ...
The great biodiversity of neotropical fish species that have external fertilization as a reproductive strategy, like the tambaqui, requires more careful analyzes in toxicological tests of the various pesticides implemented in Brazilian agriculture over the last few years. In this context, the objective of the present work was to evaluate possible sperm alterations in tambaqui (Colossoma macropomum) semen exposed to two different pesticide residues. Seminal samples of sexually mature tambaqui males from a local fish farm were used. Semen was collected eight hours after hormone induction into graduated glass tubes. After initial assessment of the lack of prior activation, the experiment was carried out in a factorial scheme, testing two pesticides widely used in agricultural systems (glyphosate and fenitrothion). For each pesticide, five concentrations were tested (6, 12, 24, 120 and 240 mg/L), with motility analysis at times 0, 30 and 60 seconds after activation. As a control, activation with 0.9% NaCl solution and motility analysis at the same times described for pesticides were used. Results indicate that in natura samples exhibited initial motility of 89.2 ± 4.9% and mean duration of 100 seconds (up to 10% sperm motility). The reduction in sperm motility occurred significantly (p < 0.05) after 30 seconds in all concentrations tested, except for the concentration of 240 mg/L because no activation was observed. The tests described here demonstrate that tambaqui semen was sensitive to the process of exposure to pesticide residues, and can be used in biomonitoring analyzes of the aforementioned agricultural pesticides.
... In habitats where the food web is severely impacted by contaminants or invasive species, resistant H. azteca may become the preferred food source (Feyrer et al., 2003;Whitley and Bollens, 2014), which can ultimately pose a risk for greater chronic exposure to fish that prey upon them. Chronic exposure to pyrethroids was shown to cause endocrine disruption (Brander et al., 2016) and alterations to behavior and reproduction in fish (Mondal et al., 2015). In addition, pyrethroids are biotransformed by H. azteca (Muggelberg et al., 2017) and studies suggest greater endocrine disruption capacity by pyrethroid metabolites compared to the parent compound in fish (Brander et al., 2016;Degroot and Brander, 2014). ...
Recent studies demonstrated pyrethroid resistance associated with voltage-gated sodium channel mutations in populations of the epibenthic amphipod, Hyalella azteca. Resistant populations were able to tolerate and bioconcentrate pyrethroids at concentrations significantly higher than toxic levels for non-resistant populations. In conjunction with elevated bioconcentration potential, environmental alteration particularly as a result of global climate change is anticipated to significantly alter abiotic parameters including temperature and salinity. These changes are expected to influence uptake and biotransformation of contaminants. Thus, the aims of the current study were a) to examine the bioconcentration potential of permethrin in two pyrethroid-resistant clades of H. azteca and b) assess the influence of temperature and salinity changes on toxicokinetic parameters. Two pyrethroid-resistant clades of H. azteca were exposed to ¹⁴C-permethrin at three salinities (0.2, 1.0 and 6.0 practical salinity units (PSU)) and temperatures (18, 23 and 28 °C). Tests were conducted for up to 36 h and uptake, elimination and biotransformation rates were calculated. Both populations demonstrated bioconcentration factors (BCFs) between five and seven times greater than published data for non-resistant H. azteca, with significant differences between clades. Calculated BCF values were comparable to field populations of resistant H. azteca, emphasizing the potential for elevated pyrethroid bioconcentration in the natural environment and increased exposure for predators consuming pyrethroid-resistant aquatic invertebrates. Alterations to temperature and salinity had no statistically significant effect on uptake or parent compound half-life in either population, though biotransformation was elevated at higher temperatures in both populations. Salinity had a variable effect between the two populations, with lower BCF values at 1.0 PSU in clade D H. azteca and greater BCFs at 6.0 PSU in clade C H. azteca. This is the first study to demonstrate the potential for future climate scenarios to influence toxicokinetics in pyrethroid-resistant aquatic organisms.
... Gonad lesions observed could have resulted in the degenerative ovarian changes, flabby oocytes, and vacuolation in the oocytes of C. gariepinus exposed to LCT. This agreed with the report of Kausik, Bodhisatwa, and Salma (2015). ...
Background
Extensive and indiscriminate use of pesticides gradually destroys the environment (ecosystem), poses serious threats to human health, animal life (especially aquatic), plant forms, soil, water, and also lead to emergence of resilient species of life forms that are becoming resistant to pesticides. The present study focused on evaluating lambda-cyhalothrin oxidative stress and gonad histoarchitecture toxicity potency in Clarias gariepinus .
Results
A total of 120 C. gariepinus 16 to 40 cm SL and 200 to 250 g bodyweights (assigned into treatments 0.00 (control), 2.5 × 10 ⁻⁴ μg/L, 5.0 × 10 ⁻⁴ μg/L, and 6.25×10 ⁻⁴ μg/L (A-D) lambda-cyhalothrin (LCT), each treatment consisted of 30 fishes, replicated three times, 10 fishes per replicate) were used for this study. On day 7, catalase activity (CAT) and glutathione peroxidase (GPx) significantly increased ( p < 0.05) in all treatments compared with control. Day 14, superoxide dismutase (SOD) and GPx significantly increased ( p < 0.05). All parameters significantly increased ( p < 0.05) on days 21 and 28 except SOD (day 21). All parameters increased significantly on day 28 across the row in all treatments. The significant increase ( p < 0.05) in SOD, (malondialdehyde) MDA, GPx, and glutathione reductase (GR) levels returned to normal after 7 days of depuration but CAT level did not return to normal. The testes photomicrographs showed necrotic conditions in the spermatogenic cells with nuclear pyknosis and cytoplasmic swelling while that of the ovary displayed vacuolations, flabby oocytes, and degenerated ovaries changes.
Conclusion
Lambda-cyhalothrin is toxic to C. gariepinus. The inability of significant increase in CAT to return to normal after 7 days of depuration further confirms our report.
... Several Neotropical species have external fertilization as a reproductive strategy, which exposes the gametes to the contaminated environment (Rodrigues et al., 2019). Thus, the entire process of fertilization and embryonic development can be directly affected by excess contaminants, greatly influencing the reproduction and renewal of fish stocks, causing an environmental imbalance and reduction in species diversity (Mondal et al., 2015). ...
Fish are the predominant group of vertebrates in aquatic environments, and they are directly affected by the presence of contaminants in water bodies, which undergo changes in the structure and function of communities and dynamics of the populations. The aim of the present study was to conduct a systematic review of studies that analyze the reproductive aspects of freshwater teleosts in environments contaminated by pesticides. A systematic search for scientific articles was carried out from 2000 to 2019 using the "Web of Science" database, using the descriptors "fish reproduction", "contamination", "toxicology", "ecotoxicity" and "biomonitoring", combined with the use of boolean operators "AND" and "OR". The content analysis was performed based on the titles and the summary, with a first screening. Then, 98 articles were read in full, with 40 being selected. 24 species of fish were recorded, with a predominance of Danio rerio (17.5%). Insecticides were present in 78% of the studies, mainly Endosulfan (35%) and Cypermethrin (13%). Reproductive endocrine disorders were the most reported pathways of action (57.5%). The effects of pesticides on the reproduction of freshwater teleosts are evident, requiring studies on structural changes in gonads and a decrease in the quality of gametes.
Commercially available insecticides present acute toxicity to the health of fish and other aquatic organisms, which may impair the local aquaculture. This study evaluated the gonadal morphology of freshwater fish exposed to pyriproxyfen and fenthion. Forty‐five juvenile male Nile tilapias (Oreochromis niloticus) were divided into control, pyriproxyfen‐exposed (0.01 g/L), and fenthion‐exposed (0.001 g/L) groups. They were evaluated in three moments (30, 60, and 90 days). The variables analyzed were the gonadosomatic index (GSI), weight to length ratio, seminiferous tubules morphometry (diameter and height), tissue damage, and immunohistochemical analysis for caspase‐3, tumor necrosis factor alpha (TNF‐α), and vascular endothelial growth factor (VEGF). Pyriproxyfen and fenthion injured the seminiferous tubule tissue, and the damage progressed according to the exposure time. In addition, the GSI gradually reduced over time in all groups compared with the first moment (30 days), while caspase‐3, TNF‐α, and VEGF values increased only in the fenthion‐exposed group. Therefore, pyriproxyfen and fenthion changed the gonadal morphology of male Oreochromis niloticus, which may affect their reproduction in the wild or captivity.
