Toxicity assessment of municipal sewage treatment plant effluent by an integrated biomarker response in the liver of crucian carp (Carassius auratus)

Antioxidant enzyme activity and pathophysiological consequences in the sludge worm Tubifex tubifex under acute and sub-lethal exposures to the fungicide Tilt ®

This study aimed to evaluate the effects of propiconazole on the tubificid segmented worm, Tubifex tubifex. The animals were exposed to various concentrations of propiconazole for 96 h to assess the acute effect of this fungicide and for subacute level animals were exposed for 14 days with 10% and 20% of the 96 h LC50 value (0.211 and 0.422 mg/l, respectively). The 96 h LC50 value was determined to be 2.110 mg/l, and sublethal propiconazole concentrations caused significant changes in the oxidative stress enzymes. When compared to control organisms, superoxide dismutase (SOD) and catalase (CAT) activity first decreases and then significantly increases on days 7 and 14. However, GST activity decreases and MDA concentration rises in a concentration- and time-dependent manner throughout the exposure period. In addition, the impacts of propiconazole on Tubifex tubifex were characterized and depicted using a correlation matrix and an integrated biomarker response (IBR) assessment. These findings suggest that exposure to this fungicide distorts the survivability and behavioral response in Tubifex tubifex at the acute level. In addition, it modulates changes in oxidative stress enzymes at the sublethal level. Furthermore, the species sensitivity distribution curve indicates that this tubificid worm has a high risk of survival in the presence of the fungicide propiconazole in aquatic ecosystems.

Impacts of Nile Tilapia (Oreochromis niloticus) exposed to microplastics in bioflocs system

Microplastics (MPs) are abundant in aquaculture water, including in bioflocs aquaculture systems. Compared with other aquaculture systems, biofloc technology systems have the richest microbes and are beneficial to cultivated organisms. Therefore, this study provides a comprehensive assessment of the potential effects of MPs on aquaculture organisms in bioflocs systems. Here, Nile Tilapia (Oreochromis niloticus) were exposed to MPs (polystyrene; 32-40 μm diameter) with 0, 80 items/L (30 μg/L), and 800 items/L (300 μg/L) for 28 days in a bioflocs aquaculture system. The results showed that the MPs generally had no apparent effect on water quality, tilapia growth, or digestive enzyme activity. However, MPs accumulated the most in the liver (5.65 ± 0.74 μg/mg) and significantly increased the hepato-somatic index of tilapia and reduced the crude protein and lipid of tilapia muscle (p < 0.05). The levels of the antioxidant enzymes catalase and glutathione S-transferase increased significantly in response to MPs (p < 0.05). In contrast, MPs did not affect the content of glutathione, glutathione peroxidase, oxidized glutathione, and malondialdehyde, or the enzyme activity of Na+/K+-ATPase. Moreover, using an improved integrated biomarker response index, growth performance was found to be less responsive to MPs than to oxidative stress and digestive activity. Exposure to MPs did not significantly influence the microbial communities of the bioflocs and tilapia guts (p < 0.05). These results suggest that MPs barely affected tilapia in the bioflocs system. This study contributes to the evaluation of the ecological risk of MPs in aquaculture systems and a better understanding of the integrated response of cultivated vertebrates to MPs in biofloc technology systems.

Enhanced removal organic compounds and particles from cooking fume using activated sludge scrubber filled loofah: From performance to the mechanism

The catering industry's growth has resulted in cooking fume pollution becoming a major concern in people's lives. As a result, its removal has become a core research focus. Natural loofah is an ideal biofilm carrier, providing a conducive environment for microorganisms to grow. This study utilized natural loofah to fill domesticated activated sludge in a bioscrubber, forming biofilms that enhance the ability to purify cooking fume. This study found that the biomass of loofah biofilms per gram is 104.56 mg. The research also determined the removal efficiencies for oils, Non-methane total hydrocarbons (NMHC), PM2.5, and PM10 from cooking fumes, which were 91.53%, 67.53%, 75.25%, and 82.23%, respectively. The maximum elimination capacity for cooking fumes was found to be 20.7 g/(m3·h). Additionally, the study determined the kinetic parameters for the biodegradation of oils (Kc and Vmax) to be 4.69 mg L-1 and 0.026 h-1, respectively, while the enzyme activities of lipase and catalase stabilized at 75.50 U/mgprots and 67.95 U/mgprots. The microbial consortium identified in the biofilms belonged to the phylum Proteobacteria and consisted mainly of Sphingomonas, Mycobacterium, and Lactobacillus, among others.

Interaction between Cr(VI) and Tubificidae in sludge reduction system: effect, reduction, and redistribution of Cr(VI)

The treatment of heavy metals in sewage treatment systems has gained more attention with the increase in heavy metal hazards. Tubificidae in sludge reduction have been widely studied; however, little is known about the effect of Tubificidae in the treatment of Cr-containing wastewater. In this study, the mechanism of Tubificidae in the sludge reduction system with Cr stress was studied. Predation experiments by Tubificidae in a Cr-containing sludge reduction system were conducted to investigate the changes in enzyme activities in the Tubificidae under different concentrations of Cr, and the distribution of Cr in the sludge reduction reactor was analyzed. The kinetic model of uptake and elimination of Cr in Tubificidae was established. The results showed that the maximum activation multiplier factor of superoxide dismutase (SOD) activity was 1.95 under the low concentration of Cr(VI), which indicated that Tubificidae had a certain detoxification. After the effect of Tubificidae on Cr(VI) experiments, the Cr concentrations in Tubificidae, sludge, and feces increased first and then decreased with exposure time, and the proportion of total Cr and Cr(VI) in the sludge decreased from 71.98% and 42.7% to 29.18% and 6.82%, respectively. The detoxification mechanism of the Tubificidae could be activated with Cr stress, and 63.22% of the Cr(VI) was converted to Cr(III). The bioconcentration factor (BCF) for theoretical equilibrium was 446, the maximum bioaccumulation factor (BAF) reached 0.97 on the 15th day. It can be seen that Tubificidae could be considered a good scavenger of environmental Cr(VI). The hyperbolic model fits the process of Cr uptake and elimination well and can be used as a predictive tool for Tubificidae accumulation.

Developmental toxicity of the emerging contaminant cyclophosphamide and the integrated biomarker response (IBRv2) in zebrafish

The safety of cyclophosphamide (CP) in the early developmental stages is not studied yet; it is important to study the responses at these stages because they might have relevance to CP-administered humans. We studied the developmental toxicity of CP by analysing physiological, morphological, and oxidative stress, neurotransmission enzymes, gene expression and histological endpoints in zebrafish embryos/larvae. The study lasted for 120 hpf at environmentally relevant concentrations of CP. No visible alterations were noticed in the control group. Delayed hatching, slow heart rate, yolk sac oedema, pericardial oedema, morphological deformities, the incompetence of oxidative stress biomarkers, excessive generation of ROS, apoptosis, inhibition of neurotransmitters and histopathological anomalies were observed in CP-treated groups. These alterations were found to be concentration- and duration-dependent effects for physiological and morphological endpoints, whereas concentration-dependent effects were antioxidants, ROS, apoptosis and histological endpoints. Biomarkers and gene expression were standardised using the integrated biomarker response-IBRv2 index. The IBRv2 index showed a concentration-dependent behaviour. A non-lethal developmental and teratogenic effect was observed in CP-treated zebrafish embryos/larvae at the studied concentrations. The studied biomarkers are sensitive, and the responses are interrelated; thus, their responses are useful to assess veiled and unseen hazards of pharmaceuticals.

Triphenylmethane dye (C52H54N4O12) is potentially a hazardous substance in edible freshwater fish at trace level: toxicity, hematology, biochemistry, antioxidants, and molecular docking evaluation study

Malachite green (C₅₂H₅₄N₄O₁₂) is a synthetic dye that is used in textile industries as a colorant and in aquaculture sectors to contain microbial damage. Aquatic contamination of malachite green (MG) has been reported globally. Fish is the highest trophic organism among aquatic inhabitants, highly sensitive to waterborne contaminants (metals, coloring agents, etc.). Toxicity of waterborne chemicals on nontarget organisms can be determined by assessing biomarkers. Assessing blood parameters and tissue antioxidants (enzymatic and nonenzymatic) is useful to evaluate MG toxicity. To initiate the MG toxicity data for freshwater fish (Cyprinus carpio), the median lethal toxicity was primarily evaluated. Then, hematological, blood biochemical (glucose, protein, and cholesterol) and tissue biochemical (amino acids, lipids), and vital tissue (gills, liver, and kidney) antioxidant capacity (CAT, LPO, GST, GR, POxy, vitamin C, and GSH) of C. carpio were analyzed under acute (LC_50-96 h) and sublethal (Treatment I-1/10^th and Treatment II-1/5^th LC_50-96 h) exposure periods (28 days). Molecular docking for MG with hemoglobin was also obtained. Biomarkers examined were affected in the MG-treated groups with respect to the control group. Significant changes (p < 0.05) were observed in hematology (Hb, RBCs, and WBCs), glucose, proteins, lipids and tissue CAT, LPO, and GST activities under acute MG exposure. In sublethal treatment groups, biomarkers studied were significant (p < 0.05) throughout the study period. The potential for MG binding to hemoglobin was tested in this study. MG is potentially a multiorgan toxicant. Literally a chemical that is harmful to the aquatic environment if safety is concerned.

Mechanistic insights to lactic and formic acid toxicity on benthic oligochaete worm Tubifex tubifex

Lactic and formic acid are two commonly found monocarboxylic organic acids. Lactic acid is discharged into the water bodies as acidic industrial effluent from the food, cosmetic, chemical, and pharmaceutical industries, whereas formic acid is discharged from various paper, leather tanning, and textile processing industries. The present study investigated the toxicity of both organic acids upon the benthic oligochaete worm Tubifex tubifex. The 96-h median lethal concentration (LC₅₀) values for lactic and formic acid are determined as 143.81 mg/l and 57.99 mg/l respectively. The effects of two sublethal concentrations (10% and 30% of 96 h LC₅₀) of these acids on differential expression of oxidative stress enzymes are investigated. The comparative analysis of acute toxicity demonstrates that formic acid exposure is more detrimental to T. tubifex than lactic acid. The in silico structural analysis predicts that formic acid can interact with cytochrome c oxidase of the electron transport system and thereby inhibits its functionality and induces reactive oxygen species production. Integrated biomarker response (IBR) analysis illustrates that overall oxidative stress of formic acid to T. tubifex is significantly higher than that of lactic acid, which supports the structural analysis. It is concluded from this study that toxicokinetic-toxicodynamic and species sensitivity distributions studies are helpful for ecological risk management of environmental toxicants.

Integrated biomarker responses of rice associated with grain yield in copper-contaminated soil

Copper (Cu) contamination in soil is an environmental issue that affects rice growth and development. This study investigated changes in photosynthetic capacities in combination with integrated biomarker responses at different growth stages of rice (Oryza sativa L. var. Hom Bai Toey) exposed to various concentrations of Cu. A randomized complete block design with four replications was used. Exposure to high copper concentrations of 200 Cu mg kg^-1 of soil and more resulted in a marked decline in the photosynthetic efficiency of Photosystem II (Phi2) but increased yield of non-photochemical quenching (PhiNPQ) and yield of non-regulatory energy dissipation (PhiNO) at tillering and flowering stages. In addition, these concentrations induced a delay in the flowering of rice, as a consequence of stress experienced in early growth stage. Significant lipid peroxidation and leaf area reduction were observed with 400 Cu mg kg^-1 treatment at flowering stage. Rice grain yield decreased significantly at copper concentrations of 200 and 400 mg kg^-1. Overall, excess copper inhibited photosynthetic capacity, growth, and development of rice in the early growth stage, and synergistic effects of yield components contributed to final grain yield reduction at harvesting stage. In addition, calculated integrated biomarker response (IBR) values reflect well the severity of Cu toxicity with a decreasing order from tillering stage to harvesting stage.

λ cyhalothrin induced toxicity and potential attenuation of hematological, biochemical, enzymological and stress biomarkers in Cyprinus carpio L. at environmentally relevant concentrations: A multiple biomarker approach

The present study was aimed to evaluate the toxic effects of a commonly used synthetic pyrethroid, λ cyhalothrin on the common carp, Cyprinus carpio L. The results depicted that 96 h LC₅₀ value of λ cyhalothrin to the fish was 1.48 μg l^-1. During 45 days of chronic exposure a significant reduction (p < 0.05) in the RBC, hemoglobin, and hematocrit value of fish was observed in λ cyhalothrin treated fish. Blood glucose, cholesterol and creatinine levels increased significantly, while total protein and albumin were significantly decreased (p < 0.05) in the exposed fish. Moreover, alanine aminotransferase and aspartate aminotransferase levels in the blood also increased significantly (p < 0.05) in the treated fish. In gills and liver, glutathione S-transferase (GST) and glutathione peroxidase (GPx) and in liver GST exhibited a significant initial augmentation followed by a subsequent reduction while catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) level increased markedly with incrementing concentrations of λ cyhalothrin in both the organs. Acetylcholinesterase (AchE) activity in both gills and liver decreased in exposed fish upon addition λ cyhalothrin. However, the hazardous effects of λ cyhalothrin on C. carpio were characterized and portrayed by the development of integrated biomarker response (IBR), and biomarker response index (BRI). GUTS-SD and IT modeling were implied for a better interpretation of the toxicity. These results indicate that exposure to λ cyhalothrin alters the survivability at the acute level and the activity of hematological, plasma biochemical as well as enzymological and stress parameters (in gills and liver) at the sublethal level in C. carpio.

Assessment of biochemical, hematological and behavioral biomarkers of Cyprinus carpio on exposure to a type-II pyrethroid insecticide Alpha-cypermethrin

This study assessed some important physiological biomarkers of freshwater edible fish Cyprinus carpio following exposure to 10 % (T1) and 20 % (T2) sublethal concentrations of Alpha-cypermethrin (A-cyp) over a total period of 45 days. Behavioral responses were noticed and Kaplan-Meier survival curves were prepared during acute toxicity study. Total serum protein concentration, total erythrocyte count, hemoglobin, packed cell volume, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and total leukocytes count were decreased significantly (p < 0.05), while the blood glucose, total serum lipid concentration, and clotting time were increased significantly (p < 0.05) over control. The most affected fish group and most significantly altered biomarker under toxic stress of A-cyp were identified using integrated biomarker response (IBR). The biomarker response index (BRI) values measured the overall health status of the treated fish and indicated that moderate adverse effects were exerted on the fish group exposed to T2 for 45 days.

Long term salinity disrupts the hepatic function, intestinal health, and gills antioxidative status in Nile tilapia stressed with hypoxia

In aquaculture, fish are stressed with several factors involved in impacting the growth rate and health status. Although Nile tilapia can resist brackish water conditions, hypoxia status may impair the health condition of fish. Nile tilapia were exposed to salinity water at 0, 10, and 20‰ for four weeks then the growth behavior was checked. The results showed meaningfully lowered growth rate, feed utilization, and survival rate when fish kept in 20‰ for four weeks. Then fish were subdivided into six groups (factorial design, 2 × 3) in normoxia (DO, 6 mg/L) and hypoxia (DO, 1 mg/L) conditions for 24 h. High salinity (10 and 20‰) combined with hypoxia stress-induced inflammatory features in the intestines, gills, and livers of fish. The activities of SOD, CAT, and GPX were increased in the intestines, gills, and livers of fish grown in 10 and 20‰ and exposed with hypoxia stress. Fish grown in 20‰ and stressed with hypoxia had the highest ALT, AST, and ALP levels (p < 0.05) among the groups. The highest transcription levels of Il-8, Il-1β, Ifn-γ, Tnf-α, and Caspase-3 genes and the lowest level of Il-10 gene were observed in fish exposed with 20‰ and hypoxia. The outputs of Integrated Biomarker Response (IBR) showed marked differences between fish groups with varied values. The lowest IBR was observed in fish reared in fresh water and normoxia, while the highest IBR was seen in the group of fish reared in 20‰ and hypoxia conditions (p < 0.05). These results confirm that Nile tilapia can tolerate 10‰ in normoxia but 20‰ salinity combined with hypoxia results in oxidative stress, apoptosis, and inflammatory features in the intestines, gills, and livers. The obtained results indicate that hypoxia can affect the performances of Nile tilapia reared in brackish or high-water salinity leading to severe economic loss. Further future studies are required to understand the impact of different water salinities with hypoxia in the short term and long-term periods on the productivity of Nile tilapia.

Acute toxicity of organophosphate pesticide profenofos, pyrethroid pesticide λ cyhalothrin and biopesticide azadirachtin and their sublethal effects on growth and oxidative stress enzymes in benthic oligochaete worm, Tubifex tubifex

The present study was aimed to assess the acute toxicity of organophosphate pesticide, profenofos; synthetic pyrethroid pesticide, λ cyhalothrin and biopesticide, azadirachtin and their sublethal effects on growth rate and oxidative stress biomarkers in Tubifex tubifex in vivo. The results showed that 96 h LC₅₀ value of profenofos, λ cyhalothrin and azadirachtin to Tubifex tubifex are 0.59, 0.13 and 82.15 mg L^-1 respectively. Pesticide treated worms showed several behavioral abnormalities including increased mucus secretion, erratic movements, wrinkling activity and decreased clumping tendency during acute exposure. The percentage of autotomy increased significantly (p < 0.05) with the increasing concentration of the pesticides at 96 h of exposure. Sublethal concentrations of profenofos (0.059 and 0.118 mg L^-1), λ cyhalothrin (0.013 and 0.026 mg L^-1) and azadirachtin (8.2 and 16.4 mg L^-1) caused significant alterations in growth rate and oxidative stress enzymes in T. tubifex during 14 days exposure period. The growth rate of the pesticide exposed worms decreased significantly (P < 0.05) in a concentration and duration-dependent manner. Superoxide dismutase (SOD), reduced glutathione (GSH), glutathione-s-transferase (GST) and glutathione peroxidase (GPx) demonstrated a noteworthy (p < 0.05) initial induction followed by a subsequent reduction, while catalase (CAT) and malondialdehyde (MDA) exhibited noteworthy induction (p < 0.05) all through the exposure time. Through principal component analysis, correlation matrix, and integrated biomarker response, the effects of profenofos, λ cyhalothrin and azadirachtin on T. tubifex were distinguished. These results indicate that exposure to profenofos, λ cyhalothrin and azadirachtin affect survivability, change the behavioral responses, reduce the growth rate and induce oxidative stress enzymes in T. tubifex.