How does sublethal permethrin effect non-target aquatic organisms?

Sub-lethal effects of deltamethrin and permethrin resulted in ultrastructural alterations in scales and oxygen uptake changes of Anabas testudineus (Bloch, 1792)

The present study used scanning electron microscopy (SEM) to assess the toxicity of sub-lethal concentrations of deltamethrin (0.035, 0.007 and 0.0007 mg L-1) and permethrin (0.93, 0.093 and 0.0093 mg L-1) on the ultrastructure of the scales of Anabas testudineus (Bloch, 1792) during a 21 day exposure. The oxygen uptake of the fish during deltamethrin (0.007 and 0.0007 mg L-1) and permethrin (0.093 and 0.0093 mg L-1) exposure was also investigated. The SEM studies revealed abnormal morphological alterations and modifications of fish scales, which were concentration-dependent. Deltamethrin-exposed fish showed severe deformation and fusion of two circuli in different rows, thereby disrupting the normal radii pattern. This fusion was probably caused by the cyanide moiety of the pesticide. On the other hand, permethrin characteristically produced a thick mucus layer over the scale surface. The different concentrations of both the pesticides affected circuli pattern with severe breakage of circuli and loss of lepidonts present over their ridges. Erythrocyte extrusions were also seen at several places over the scale surface. There was significant reduction of oxygen uptake in fish exposed to permethrin at both the concentrations, but in deltamethrin treatments significant reduction occurred only at the higher concentration of 0.007 mg L-1, though this was less than the lower permethrin concentration of 0.0093 mg L-1, and moreover effects of both the pyrethroids on oxygen consumption increased at higher concentrations.

Synergistic impact of nanoplastics and nanopesticides on Artemia salina and toxicity analysis

Polystyrene nanoplastics (PSNPs) when exposed to nanopermethrin (NPER) exacerbate toxicity on Artemia salina. In the environment, NPs act as a vector for other pollutants mainly heavy metals and pesticides. Nanopesticides are efficient compared to their bulk form. The adsorption of NPER on PSNPs was studied systematically and it was found that the binding of NPER is inversely proportional to its concentration. NPER adsorption on PSNPs followed pseudo-first-order kinetics with an adsorption percentage of 1.7%, 3.7%, 7.7%, 15.4%, and 30.8% when PSNPs were incubated with 2 mg L-1,4 mg L-1, 8 mg L-1, 16 mg L-1, and 32 mg L-1 of NPER. The adsorption followed the Langmuir isotherm. The increased hydrodynamic size of the NPER/PSNP complex was observed. Different characterization studies were performed for NPER, PSNPs, and their complex using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, and gas chromatography-mass spectrometry. The LC50 value for the NPER/PSNP complex treated with Artemia salina was 3.127 mg L-1, compared to LC50 NPER which was found to be 4.536 mg L-1. PSNPs had a lower mortality rate in Artemia salina, where 50% mortality (LC50) was not observed at their working concentration. Both the nanoforms led to morphological changes in Artemia salina. Reactive oxygen species increased to 87.94% for the NPER/PSNP complex, 78.93% for NPER, and 23.65% for PSNPs. Greater amounts of ROS in the cells may have led to SOD degradation. Superoxide dismutase activity for the NPER/PSNP complex was 1.2 U mg-1, NPER was 1.3 U mg-1, and PSNPs was 2.1 U mg-1. A lipid peroxidation study reveals that the melondialdehyde synthesis by NPER/PSNPs complex, NPER and PSNPs were found to be 2.21 nM mg-1, 1.59 nM mg-1, and 0.91 nM mg-1 respectively. Catalase activity in a complex of NPER/PSNPs, NPER, and PSNPs was found to be 1.25 U mg-1, 0.94 U mg-1, and 0.49 U mg-1. This study envisages the individual and combined toxicity of nanopesticides and PSNPs on aquatic organisms. Increased plastic usage and new-age chemicals for agriculture could result in the formation of a PSNPs-NPER complex potentially causing highly toxic effects on aquatic animals, compared to their pristine forms. Therefore, we should also consider the other side of nanotechnology in agriculture.

Evaluation of Possible Toxic Effects of Boric Acid in Palourde Clam (Ruditapes decussatus) Through Histological Changes and Oxidative Responses

The extensive utilization of boric acid, particularly in industrial and agricultural sectors, also engenders concerns regarding the toxicity of boron and its derivatives. Particularly, the behavior of boric acid at increasing concentrations in aquatic ecosystems remains poorly understood. In light of these concerns, this study aimed to investigate the toxicity of boric acid in bivalves, which occupy a critical position in the food chain. Specimens of Ruditapes decussatus, which had not been previously exposed to any pollutants and were cultivated under controlled conditions, were subjected to three different concentrations of boric acid (0.05 mg/L, 0.5 mg/L, and 5 mg/L) in vitro for 96 h. Following the exposure period, the specimens were assessed for histological changes (the mantle, gill, and digestive gland) and specific oxidative parameters (the gill and digestive gland), including superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase, and lipid peroxidation (LPO). The research findings indicated that boric acid primarily induced oxidative damage at the applied concentrations and increased antioxidant levels (p < 0.05). Moreover, although no significant histopathological abnormalities were observed in the examined histological sections, subtle changes were noted. This study evaluated the potential adverse effects of boric acid on bivalves, which are crucial components of the aquatic food chain, utilizing histological and specific physiological parameters following its introduction into aquatic environments. It is anticipated that the findings of this study will contribute to the development of new insights and perspectives regarding the extensive use of boric acid.

How do biocidals affect the non-target marine organisms: the short-term effects of antifouling agent sodium pyrithione on Mediterranean mussels (Mytilus galloprovincialis, Lamark 1819)

The metallic pyrithiones are used as antifouling paints for marine vehicles against fouling organisms. However, they are dissolved in marine water and have negative impacts on marine non-target organisms. This study evaluated the adverse effects of sodium pyrithione (NaPT) on Mytilus galloprovincialis using total hemocyte counts (THCs), oxidative stress and antioxidant parameters, and histopathological observations. Mussels were exposed to 0.1 and 1 μg/L NaPT for 96 h. The THC values of the NaPT-exposed mussels significantly decreased (p < 0.05). Lipid peroxidation and advanced oxidative protein products of digestive gland and gill tissues were decreased but only the digestive gland tissues of 0.1 μg/L NaPT values were significantly decreased compared to control groups (p < 0.05). Histological alterations were observed in the gill and the digestive gland tissues revealing malformations and hyperplasia of gill lamella; degenerations and loss of tubules of digestive gland after exposure to NaPT for 96 h. As a result, biocidal sodium pyrithione has adverse effects on the mussels even in short-term exposures and low concentrations.

Deciphering the interplay between LPS/TLR4 pathways, neurotransmitter, and deltamethrin-induced depressive-like behavior: Perspectives from the gut-brain axis

The improper use of deltamethrin (DM) can result in its accumulation in soil, water, food, and even the human body, which is associated with an elevated risk of neurotoxicity and behavioral abnormalities; however, the underlying mechanisms remain insufficiently investigated. Emerging evidence underscores the significance of the gut-brain axis in central nervous system (CNS) dysfunctions. Accordingly, this study investigates the role of the gut-brain axis in DM-induced behavioral anomalies in mice. The results showed that DM exposure induced depressive-like behavior, and the hippocampus, the region that is responsible for the modulation of emotional behavior, showed structural integrity disrupted (neuronal nuclear shrinkage and decreased tight junction protein expression). In addition, DM exposure led to compromised gut barrier integrity (disruptions on crypt surfaces and decreased tight junction protein expression), which might contribute to the gut bacterial-derived lipopolysaccharide (LPS) leakage into the bloodstream and reaching the brain, triggering LPS/toll-like receptor (TLR) 4 -mediated increases in brain pro-inflammatory cytokines. Subsequently, we observed a disturbance in neurotransmitter metabolic pathways following DM exposure, which inhibited the production of 5-hydroxytryptamine (5-HT). Additionally, DM exposure resulted in gut microbiota dysbiosis. Characteristic bacteria, such as Alistipes, Bifidobacterium, Gram-negative bacterium cTPY-13, and Odoribacter exhibited significant correlations with behavior, tight junction proteins, inflammatory response, and neurotransmitters. Further fecal microbiota transplantation (FMT) experiments suggested that DM-induced gut microbiota dysbiosis might contribute to depressive-like behavior. These results provide a new perspective on the toxicity mechanism of DM, indicating that its neurotoxicity may be partially regulated by the microbiota-gut-brain axis.

Delineating involvement of MAPK/NF-κB pathway during mitigation of permethrin-induced oxidative damage in fish gills by melatonin

Present study evaluated involvement of transcription factors during permethrin-induced gill toxicity and its amelioration by melatonin. First, adult Notoptertus notopterus females were exposed to permethrin at nominal concentrations [C: 0.0, P1: 0.34, P2: 0.68 µg/L] for 15 days followed by intramuscular melatonin administration (100 µg/kg body weight) for 7 days. Gill MDA, XO, LDH levels increased, while Na+-K+-ATPase, SDH, cytochrome C oxidase levels decreased with increasing permethrin concentrations. Glutathione, SOD, CAT, GST, GRd levels increased in P1 than C, but decreased in P2 than P1, C. Melatonin administration restored gill enzyme and antioxidant levels in P1, P2. Next, isolated gill tissues were exposed to permethrin at 25, 50 µM doses along with melatonin administration (100 μg/mL). NF-κB, NRF2, Keap1, ERK, Akt, caspases protein expression changed significantly during permethrin-induced gill damage. Melatonin administration amended permethrin-induced molecular imbalance through modulation of caspase proteins and MAPK/NF-κB signal transduction pathway via melatonin receptor 1.

Microbial Diversity and Enzyme Activity as Indicators of Permethrin-Exposed Soil Health

Owing to their wide range of applications in the control of ticks and insects in horticulture, forestry, agriculture and food production, pyrethroids pose a significant threat to the environment, including a risk to human health. Hence, it is extremely important to gain a sound understanding of the response of plants and changes in the soil microbiome induced by permethrin. The purpose of this study has been to show the diversity of microorganisms, activity of soil enzymes and growth of Zea mays following the application of permethrin. This article presents the results of the identification of microorganisms with the NGS sequencing method, and of isolated colonies of microorganisms on selective microbiological substrates. Furthermore, the activity of several soil enzymes, such as dehydrogenases (Deh), urease (Ure), catalase (Cat), acid phosphatase (Pac), alkaline phosphatase (Pal), β-glucosidase (Glu) and arylsulfatase (Aryl), as well as the growth of Zea mays and its greenness indicators (SPAD), after 60 days of growth following the application of permethrin, were presented. The research results indicate that permethrin does not have a negative effect on the growth of plants. The metagenomic studies showed that the application of permethrin increases the abundance of Proteobacteria, but decreases the counts of Actinobacteria and Ascomycota. The application of permethrin raised to the highest degree the abundance of bacteria of the genera Cellulomonas, Kaistobacter, Pseudomonas, Rhodanobacter and fungi of the genera Penicillium, Humicola, Iodophanus, Meyerozyma. It has been determined that permethrin stimulates the multiplication of organotrophic bacteria and actinomycetes, decreases the counts of fungi and depresses the activity of all soil enzymes in unseeded soil. Zea mays is able to mitigate the effect of permethrin and can therefore be used as an effective phytoremediation plant.

Pyrethroid-induced oxidative stress and biochemical changes in the primary mussel cell cultures

Pyrethroids are among the most widely used insecticides. Permethrin and tetramethrin, which are synthetic pyrethroids, are generally used to control insects in agricultural areas and household applications. Due to broad use areas, they contaminate aquatic ecosystems and cause adverse effects to the non-target aquatic organisms. Even though permethrin and tetramethrin are known to alter the oxidative stress parameters of in vivo aquatic animal model organisms, there are limited studies in vitro. This study aims to determine the adverse effects of permethrin and tetramethrin in the in vitro models of freshwater mussels exposed to 1 mg/L, 10 μg/L, 100 ng/L and 1 ng/L concentrations of chemicals for 24 h. For this purpose, reduced glutathione activities were evaluated as biomarkers of the primary gill and digestive gland cell cultures. In both cell cultures, reduced glutathione values increased in the exposed groups, compared to the control group. Even though the results showed that reduced glutathione activities had not significantly changed concentration-dependently (p > 0.05), significant differences were observed in the reduced glutathione activities of both cell cultures (p < 0.05). This study showed that permethrin and tetramethrin had highly toxic effects in the in vitro models of mussels even at low concentrations.

The Impact of Permethrin and Cypermethrin on Plants, Soil Enzyme Activity, and Microbial Communities

Pyrethroids are insecticides most commonly used for insect control to boost agricultural production. The aim of the present research was to determine the effect of permethrin and cypermethrin on cultured and non-cultivated bacteria and fungi and on the activity of soil enzymes, as well as to determine the usefulness of Zea mays in mitigating the adverse effects of the tested pyrethroids on the soil microbiome. The analyses were carried out in the samples of both soil not sown with any plant and soil sown with Zea mays. Permethrin and cypermethrin were found to stimulate the multiplication of cultured organotrophic bacteria (on average by 38.3%) and actinomycetes (on average by 80.2%), and to inhibit fungi growth (on average by 31.7%) and the enzymatic activity of the soil, reducing the soil biochemical fertility index (BA) by 27.7%. They also modified the number of operational taxonomic units (OTUs) of the Actinobacteria and Proteobacteria phyla and the Ascomycota and Basidiomycota phyla. The pressure of permethrin and cypermethrin was tolerated well by the bacteria Sphingomonas (clone 3214512, 1052559, 237613, 1048605) and Bacillus (clone New.ReferenceOTU111, 593219, 578257), and by the fungi Penicillium (SH1533734.08FU, SH1692798.08FU) and Trichocladium (SH1615601.08FU). Both insecticides disturbed the growth and yielding of Zea mays, as a result of which its yield and leaf greenness index decreased. The cultivation of Zea mays had a positive effect on both soil enzymes and soil microorganisms and mitigated the anomalies caused by the tested insecticides in the microbiome and activity of soil enzymes. Permethrin decreased the yield of its aerial parts by 37.9% and its roots by 33.9%, whereas respective decreases caused by cypermethrin reached 16.8% and 4.3%.

Does persistent organic pollutant PFOS (perfluorooctane sulfonate) negative impacts on the aquatic invertebrate organism, Astacus leptodactylus [Eschscholtz, 1823]

Highly persistent perfluorooctane sulfonate (PFOS) is an industrial fluorinated organic chemical with significant bioaccumulation and biomagnification properties. The purpose of this study was to determine the toxic effects of sublethal PFOS on the aquatic invertebrate organism, narrow-clawed crayfish [Astacus leptodactylus Eschscholtz, 1823]. The 96 h LC₅₀ value was determined as 48.81 mg/L (34.19-63.68 mg/L) with probit analysis. The sublethal experimental design was formed into four groups solvent control (DMSO, dimethyl sulphoxide), non-treated control group, and 1/10 (5 mg/L) and 1/100 (0.5 mg/L) of 96 h LC₅₀ of PFOS, and crayfish were exposed for 48 h, 7 d, and 21 d under laboratory conditions. Total haemocyte counts (THCs) decreased, while the haemolymph total antioxidant status (TAS) values increased (p < 0.05) after exposure to 0.5 and 5 mg/L PFOS for 48 h, 7 d, and 21 d. Haemolymph total oxidative stress (TOS) levels significantly increased at 5 mg/L PFOS concentration (p < 0.05). Catalase (CAT) activities increased at both concentrations after 48 h and 7 d and then returned to control levels after 21 d; whereas superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities did not change in muscle tissue (p > 0.05). GPX and CAT activities decreased, but SOD activity increased in hepatopancreas tissue (p < 0.05). SOD activity at both concentrations and CAT activity at 5 mg/L PFOS exposure decreased in gill tissue, while GPX activity increased at both concentrations of 48 h and 7 d and returned to control values on day 21 of exposure. Histopathological alterations were detected in hepatopancreas and gill tissues. Lamellar deformations, epithelial hyperplasia, and haemocytic infiltrations were observed in the gill tissues, whereas tubular degeneration, tubule loss, necrosis, and lesions in the hepatopancreas tissues were the major recorded alterations. As a result, the sublethal concentrations of PFOS have toxic effects on crayfish and histologically cause tissue damage. Our findings also support a better understanding of the early toxicological effects of PFOS in freshwater ecosystems. Also, it could be concluded that A. leptodactylus is a reliable model for examining histopathological alterations and differences in enzyme activities together with the haemolymph findings in toxicology studies amid aquatic species.

Acute toxicity and teratogenicity of carbaryl (carbamates), tebufenpyrad (pyrazoles), cypermethrin and permethrin (pyrethroids) on the European sea bass (Dicentrarchus labrax L, 1758) early life stages

The toxicity of carbaryl, tebufenpyrad, cypermethrin and permethrin was evaluated in European sea bass Dicentrarchus labrax during the embryonic and larval development using six different concentrations per chemical. The order of the toxicity effectiveness was carbaryl > tebufenpyrad > cypermethrin > permethrin. The larvae were more sensitive to all tested chemicals than embryos. The LC50 of carbaryl, tebufenpyrad, cypermethrin and permethrin was determined as 13.88, 43.96, 92 and 142 ppm and 9.27, 25.67, 48.4 and 72.7 ppm in embryo and larvae, respectively. Furthermore, the tested pesticides exhibited teratogenic effects on D. labrax embryo-larval stages. The observed malformations were coagulation, no spherical egg, unhatched egg, pericardial oedemata, yolk oedemata, lordosis, kyphosis, scoliosis, no eye, cranial deformation and body atrophy. Malformations were induced with 0.5 ppm carbaryl, 10 ppm tebufenpyrad and 50 ppm cypermethrin and permethrin; the highest rates of malformation were noted with 16 ppm carbaryl, 160 ppm tebufenpyrad, 400 ppm cypermethrin and 400 ppm permethrin as 34.5%, 28%, 17.5% and 16%, respectively. A positive correlation between the incidence of malformation and the increase of pesticide concentration was established.

Mechanical Acaricides Active against the Blacklegged Tick, Ixodes scapularis

Cases of Lyme disease in humans are on the rise in the United States and Canada. The vector of the bacteria that causes this disease is the blacklegged tick, Ixodes scapularis. Current control methods for I. scapularis mainly involve chemical acaricides. Unfortunately, ticks are developing resistance to these chemicals, and more and more, the public prefers non-toxic alternatives to chemical pesticides. We discovered that volcanic glass, Imergard^TM WP, and other industrial minerals such as Celite 610 were efficacious mechanical insecticides against mosquitoes, filth flies, and agricultural pests. In this report, when 6-10- and 50-70-day old unfed I. scapularis nymphs were dipped for 1-2 s into Celite, the time to 50% mortality (LT₅₀) was 66.8 and 81.7 min, respectively, at 30 °C and 50% relative humidity (RH). The LT₅₀ was actually shorter at a higher 70% RH, 43.8 min. Scanning electron microscopy showed that the ticks were coated over most of their body surface, including partial to almost total coverage of the opening to their respiratory system. The other mechanical insecticide, Imergard, had similar efficacy against blacklegged unfed nymphs with an LT₅₀ at 30 °C and 50% RH of 70.4 min. Although more research is needed, this study suggests that industrial minerals could be used as an alternative to chemical pesticides to control ticks and Lyme disease.

The effects of invasive epibiont Dreissena polymorpha on the narrow-clawed crayfish (Astacus leptodactylus, Astacidae) in Eğirdir Lake, Turkey: a case study

In aquatic ecosystems, organisms are in a close relationship with each other. While this relationship is sometimes beneficial for both species, it can sometimes be harmful to one species. This study aimed to investigate the effects of colonized zebra mussels Dreissena polymorpha on the growth parameters and total hemocyte counts of the narrow-clawed crayfish Astacus leptodactylus from Eğirdir Lake (Turkey). Zebra mussels were found on various body parts of crayfish and the most intense (44.7%) colonization was in the carapace region. There were significant differences between various biometric data and ratios of the narrow-clawed crayfish with epibiont D. polymorpha and without epibiont D. polymorpha (the control group) in terms of total length, abdomen width, arm length and chelae length, carapace width/carapace length, carapace length/abdomen length, abdomen width/carapace width, and chelae width/chelae length (p < 0.05). When the total hemocyte counts were examined, lower values ​were obtained in the narrow-clawed crayfish with zebra mussels compared to the control group (p < 0.05). As a result, epibiont organisms have negative effects on the health and growth status of the host organisms considering total hemocyte counts and biometric data.

Physiological and histopathological alterations in Capoeta baliki and Squalius pursakensis after caused by some environmental pollutants

The present study was aimed to apply physiological and histological biomarkers of pelagic and benthic fish species as biomonitoring of environmental pollutants. Capoeta baliki and Squalius pursakensis were caught from 5 stations in Kirmir Stream (Turkey). After measuring the total length and weight for condition factor analysis, liver, gill, brain, and kidney tissues of fish were taken for histopathological analysis. Dorsal muscles of fish tissues were analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). The mean condition factor of C. baliki and S. pursakensis were 1.14 and 0.97, respectively. It was indicated that the first one was in good condition than the latter one. According to histopathological observations, the alterations in the tissues may be associated with the environmental pollutants' exposure. The total concentration of PAHs of dorsal muscle of C. baliki and S. pursakensis found ranged from 0.915 to 108.421 µg/kg and 0.601 to 675.248 µg/kg, respectively. The highest total concentrations of OCPs were found as 44.16 µg/kg for C. baliki and as 562.12 µg/kg for S. pursakensis. The PCB 28 (10.83 µg/kg), PCB 52 (10.92 µg/kg), PCB 138 (226.24 µg/kg), and the total concentrations of PBDEs were found as 151.74 µg/kg in only S. pursakensis. The result of the concentrations of the investigated pollutants was generally found higher in S. pursakensis which is a higher trophic level than C. baliki. Histopathological alterations were detected as hyperemia in liver, gill, and brain; as hydrophobic degeneration in liver; hyperplasia in gill; and tubular degeneration in kidney tissues of both species. The obtained result of the study shows that the environmental pollutants may affect the physiological and histological status of fish.

How pollution effects the immune systems of invertebrate organisms (Mytilus galloprovincialis Lamark, 1819)

Hemocytes are the main immunologic parameters for invertebrate organisms as a response to diseases and pollutions. This study was aimed to reveal the relations between pollution and the total and differential hemocytes numbers. The gulf of İzmir was selected as location for sampling due to its contaminated by different anthropogenic pollutants mainly industrial effects. The effects of the pollutants were investigated on the mussels that have been collected from eight stations in the Izmir Bay (1- Inciralti, 2- Göztepe 3-Konak-4- Pasaport 5-Alsancak, 6-Karşıyaka, 7-Bostanlı), which are known as the most polluted part of inner Bay of Izmir (Western Coast of Turkey) and 8-Foça, (an anthropogenically industrialized and shipping -impacted area). The pollution effects in the bay were determined on hemolymphs by biomarkers such as total hemocyte counts (THCs) and differential hemocyte counts (DHCs). Microscopic examinations have shown the statistical differences at THCs and DHCs. The highest total hemocyte number was determined in the station 7 (Bostanlı) and the lowest in the station 4 (Pasaport) (P < 0.05). The number of total hemocyte counts were not differed significantly in the Stations among 2 (Göztepe), 5 (Alsancak) and 6 (Karşıyaka), and between Stations 8 (Foça) and 1 (Inciraltı) (P > 0.05). In addition, there have been significant differences in subpopulation according to differential hemocyte numbers. The results indicate that the station 8 (reference site-Foça) has the highest agranulocyte number while station 7 (Bostanlı) and the station 1 (İnciraltı) have the lowest agranulocyte numbers (P < 0.05). As for the basophilic hemocyte numbers, this situation was reversed highest number in station 1 (Inciraltı) and 7 (Bostanlı) and lowest in the station 8 (Foça) (p < 0.05). The station 4 (Pasaport) has the highest eosinophilic hemocyte number while station 8 (Foça) has the lowest. We concluded that differential hemocytes counts are more sensitive as biomarker with the highest numbers of agranulocytes and lowest numbers of eosinophilic and basophilic hemocytes in reference site.