Biochemical and histological effects of sub-chronic exposure to atrazine in crayfish Cherax destructor

Acute atrazine intoxication in heifers: Case report and toxicological studies

Atrazine is a triazine organochloride herbicide, frequently used in different agricultural activities. Rare acute intoxication with atrazine is reported in production animals, and its metabolism in mammals is unknown. We report a spontaneous case of atrazine acute intoxication in 16.1% animals of a 168-beef heifer herd exposed to the herbicide at a farm located in Buenos Aires province, Argentina. Affected heifers showed different neurological signs and died suddenly, similar to the previous natural atrazine intoxication report. During autopsy, no gross lesions were observed. Different body fluids and tissues samples were collected during postmortem examination. No relevant histopathological findings were observed. High levels of atrazine and its metabolites were detected in different fluids and tissues by ultra-liquid chromatography high performance coupled to triple quadrupole mass spectrometry. These findings suggest ruminal or hepatic metabolization of atrazine in the exposed cattle. This is the first report of quantification and distribution of atrazine and its metabolites in intoxicated mammals providing relevant information for diagnostic purposes.

Biological-based techniques for real-time water-quality studies: Assessment of non-invasive (swimming consistency and respiration) and toxicity (antioxidants) biomarkers of zebrafish

Swimming consistency and respiration of fish are recognized as the non-invasive stress biomarkers. Their alterations could directly indicate the presence of pollutants in the water ecosystem. Since these biomarkers are a routine process for fish, it is difficult to monitor their activity manually. For this reason, experts employ engineering technologies to create sensors that can monitor the regular activities of fish. Knowing the importance of these non-invasive stress biomarkers, we developed online biological behavior monitoring system-OBBMS and online biological respiratory response monitoring system-OBRRMS to monitor real-time swimming consistency and respiratory response of fish, respectively. We continuously monitored the swimming consistency and respiration (OCR, CER and RQ) of zebrafish (control and atrazine-treatments) for 7 days using our homemade real-time biological response monitoring systems. Furthermore, we analyzed oxidative stress indicators (SOD, CAT and POD) within the vital tissues (gills, brain and muscle) of zebrafish during stipulated sampling periods. The differences in the swimming consistency and respiratory rate of zebrafish between the control and atrazine treatments could be precisely differentiated on the real-time datasets of OBBMS and OBRRMS. The zebrafish exposed to atrazine toxin showed a concentration-dependent effect (hypoactivity). The OCR and CER were increased in the atrazine treated zebrafish. Both Treatment I and II received a negative response for RQ. Atrazine toxicity let to a rise in the levels of SOD, CAT and POD in the vital tissues of zebrafish. The continuous acquisition of fish signals is achieved which is one of the main merits of our OBBMS and OBRRMS. Additionally, no special data processing was done, the real-time data sets were directly used on statistical tools and the differences between the factors (groups, photoperiods, exposure periods and their interactions) were identified precisely. Hence, our OBBMS and OBRRMS could be a promising tool for biological response-based real-time water quality monitoring studies.

Ecological Toxicity of Cyantraniliprole against Procambarus clarkii: Histopathology, Oxidative Stress, and Intestinal Microbiota

Cyantraniliprole is a novel insecticide recently introduced for rice pest control that may cause potential threats to the red swamp crayfish (Procambarus clarkii) in rice-crayfish coculture systems. In this study, we investigated the acute toxicity of cyantraniliprole against P. clarkii with a LC50 value of 149.77 mg/L (96 h), first. Some abnormal behaviors of P. clarkii treated with 125 mg/L cyantraniliprole, including incunabular hyperexcitability, imbalance, inactivity, and increased excretion were observed. Moreover, it was observed that exposure to 5 mg/L cyantraniliprole for 14 days resulted in histopathological alterations in abdominal muscle, gills, hepatopancreas, and intestines. Furthermore, exposure to 0.05 and 5 mg/L cyantraniliprole induced increased activities of several oxidative stress-related enzymes, which was verified by the upregulation of related genes. Additionally, dysregulation of the intestinal microbiota was determined via 16S rRNA sequencing. These results will provide the basis for the utilization of cyantraniliprole in the fields of rice-crayfish integrated system.

Atrazine contaminated sites and bullfrog tadpoles: evasive trends and biochemical consequences

Atrazine (ATZ) is one of the most used active principles in agricultural systems. This pesticide has the ability to easily accumulate in terrestrial and aquatic environments, causing impacts with chronic adverse effects. Avoidance tests are tests that seek to assess the concentration from which a given organism escapes, that is, migrates to another habitat. They are being used as a modality of innovative and minimally invasive ecotoxicological tests. Our objective was to evaluate the sensitivity and possible toxic effects of ATZ in bullfrog tadpoles (Lithobates catesbeianus), through avoidance tests and oxidative stress analyses. We performed the behavioral avoidance test lasting 12 h, with observations every 60 min in a linear multi-compartment system with seven compartments. Each compartment corresponded to a concentration: negative control, 1, 2, 20, 200, 2000, 20,000 µg L^-1. After the selection of habitat, organisms were forcedly maintained in the chosen concentrations for 48 h and then, metabolic effects were measured assessing the blood plasma amino acid profile and liver protein degradation. We also determined the effective concentrations of ATZ tested at 0 h and 48 h. The results showed that there was an effect of the treatment on the distribution of tadpoles, but not on the hours or on the combined effect (interaction). The biochemical analyses also showed a concentration-dependent relationship which caused significant toxic effects even in a short period of time. In conclusion, these frogs were able to avoid places with high concentrations of ATZ in the first hours of exposure, which suggests that in the natural environment these animals can migrate or avoid areas contaminated by this herbicide; however, depending on the selected concentration, serious biochemical consequences can occur.

Effect of dietary Bacillus subtilis supplement on Cd toxicokinetics and Cd-induced immune and antioxidant impairment of Procambarus clarkii

Cadmium (Cd), a non-biodegradable contaminant in freshwater ecosystems, can pose a serious threat to aquatic animals at high levels. In this study, the Cd toxicokinetics and the immune and antioxidant defense were explored in Procambarus clarkii exposed to different levels of Cd (0, 0.1, 1.0 mg Cd/L) or treated with 1.0 mg Cd/L and dietary Bacillus subtilis supplementation (1 × 10⁷ cfu/g). Results from the 21-day uptake and depuration experiment revealed that Cd exposure elicited a dose- and time-dependent uptake in all crayfish tissues, and the rank order of Cd concentration was gill > hepatopancreas > exoskeleton > muscle. The one-compartment model demonstrated that gills had the highest uptake rate (k_u) value after Cd aqueous exposure and the k_u and elimination rate (k_d) values in gill, hepatopancreas, and exoskeleton of the group with 1.0 mg Cd/L were higher than those of the group at alow Cd concentration (0.1 mg Cd/L). However, B. subtilis could decrease Cd k_u and increase Cd k_d in hepatopancreas, resulting in the reduction of bioconcentration factors (BCF), steady-state concentrations (C_ss), and biological half-life (T_b1/2). A positive correlation was found between aqueous Cd concentration and the severity of hepatopancreas histopathological injury, while B. subtilis could ameliorate the pathological damage in the high Cd group. Similarly, aqueous exposure to Cd elevated malonaldehyde (MDA) content and suppressed the activities of lysozyme (LZM), acid phosphatase (ACP) in hepatopancreas and alkaline phosphatase (AKP) in hemolymph. The activities of superoxide dismutase (SOD) and catalase (CAT) in hepatopancreas were also inhibited. Nevertheless, they were all recovered with the dietary addition of B. subtilis. In conclusion, our results indicated that exposure to Cd significantly increased Cd accumulation and toxic damages in crayfish hepatopancreas, while dietary administration of B. subtilis to crayfish significantly decreased Cd accumulation and improved the immune and antioxidant defense, leading to the prevention in toxic effects of Cd.

Effect of Air Exposure and Re-Submersion on the Histological Structure, Antioxidant Response, and Gene Expression of Procambarus Clarkii

Air exposure is an important environmental stressor during the transportation and cultivation of Procambarus clarkii. We evaluated the effect of re-submersion for 24 h after dry transportation for 24 h on the histological structure, antioxidant activity, and gene expression of crayfish. The antioxidant parameters of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and lactate dehydrogenase (LDH), and the relative expression of CAT, SOD, HSP70, and ferritin genes were subsequently measured in the hepatopancreas and gills at both stages. Histopathology found that air exposure led to vacuolation of the hepatopancreas and disorderly arrangement of respiratory epithelial cells (REC) in the gills. The activities of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and lactic dehydrogenase (LDH) in the hepatopancreas and gills increased with short-term air exposure. The relative expression of genes (CAT, SOD, HSP70, and Ferritin) were induced after short-term air exposure. During re-submersion, MDA content and CAT and SOD activities in the hepatopancreas and gills were restored after 24 h, however, LDH activity and hepatopancreatic tissue damage were not repaired. Our results indicate that air exposure can cause oxidative damage to P. clarkii, and CAT and SOD can be used to determine the response of crayfish exposed to air, in addition to some damage that can be eliminated after re-submersion to a limited degree. This study provides foundational data that re-submersion can improve crayfish performance under hypoxic stress to a certain extent and will lead to the development of more effective transportation strategies and decrease economic losses in the future.

Atrazine exposure induces necroptosis through the P450/ROS pathway and causes inflammation in the gill of common carp (Cyprinus carpioL.)

Atrazine (ATR) is used worldwide and has been confirmed be hazardous materials that harmful to the health of organisms. Since ATR was more persistent in the water, the specific damage caused by ATR to aquatic organisms should be concern. The role of P450/ROS has been proposed in many pathomechanisms. To explore whether P450/ROS mediated necroptosis and promote inflammatory response caused by ATR exposure, 120 common carp (Cyprinus carpio L.) were randomly divided into four groups which were exposed to 0 μg/L, 4 μg/L, 40 μg/L and 400 μg/L ATR respectively. The residual levels of ATR and its metabolites increased, signs of necrosis and inflammation were found in the gills of the ATR-treatment groups. The levels of ROS and cytochrome P450 content were increased, and P450 enzymes were activated. The expression levels of the core components of necroptosis (RIPK1, RIPK3 and MLKL) increased. Moreover, gene expression of inflammatory factors (TNF-α, NF-κB, iNOS, COX-2, IL-1β and PTGE) increased significantly in the ATR-spiked group. Our results suggested that ATR exposure triggered necroptosis through the P450/ROS pathway and causes inflammation of common carp gill. This study provides valuable clue about the mechanism by which ATR causes injury to common carp gill.

Environmentally relevant atrazine exposure leads to increases in DNA damage and changes in morphology in the hepatopancreas of crayfish (Faxonius virilis)

The herbicide atrazine is widely used for controlling broad leaf weeds and increasing crop yields in agricultural areas. Atrazine enters aquatic environments through runoff, ground water discharge and seepage where concentrations have been recorded above 300 ppb. Exposure to the herbicide atrazine at environmentally relevant concentrations has been shown to negatively impact aquatic organisms, including crayfish. Because xenobiotics are concentrated in the crayfish hepatopancreas (digestive gland), we examined changes in morphology and DNA damage in hepatopancreatic tissue structure and cells following a 10-day exposure to atrazine (0, 10, 40, 80, 100 and 300 ppb). We found that there were marked morphological changes, post-exposure, for all atrazine concentrations tested. Hepatopancreatic tissue exhibited degenerated tubule epithelium with necrosis of microvilli, tubule lumen dilation, changes in tubular epithelium height and vacuolization of the epithelium. Likewise, we also performed a terminal deoxynucleotidyl transferase (TdT) mediated dUTP nick-end labeling (TUNEL) assay which showed the percentage of cells with DNA damage increased following atrazine exposure. Crayfish hepatopancreatic tissue displayed significant increases in TUNEL-positive cells following exposure to atrazine at 100 ppb and above. Overall, exposure to atrazine at environmentally relevant concentrations damages hepatopancreatic tissue. This impairment could lead to changes in biotransformation, detoxification, digestion and molting, subsequently reducing crayfish populations and negatively impacting the aquatic ecosystem.

Oxidative stress in the freshwater shrimp Caridina africana following exposure to atrazine

The toxicity of pesticides to non-target organisms continues to be important in understanding the dynamic interactions between anthropogenic chemicals and ecosystem health. This study assesses biochemical markers to determine the effects that varying concentrations of atrazine (13.1-5557 µg/l) have on the freshwater shrimp, Caridina africana. Exposure and oxidative stress biomarkers were analysed and followed by univariate, integrated biomarker response v2 (IBRv2) and Kendall Tau correlation statistical analyses, to gain insight into the concentration-dependent responses. Oxidative stress biomarkers such as reduced glutathione content (GSH), glutathione-S-transferase activity (GST), superoxide dismutase activity (SOD) and catalase activity (CAT) were significantly correlated with increasing atrazine exposure concentration (p < 0.01). Bimodality has been seen when looking at both the univariate statistically significant differences as well as the IBRv2, with the first peak at 106.8 µg/l and the second peak at 5557 µg/l atrazine. The results indicate that while individual responses may indicate statistically significant differences, using correlation and integrated statistical analysis can shed light on trends in the adaptive response of these.

Effects of the Herbicide Atrazine on Crustacean Reproduction. Mini-Review

Atrazine, one of the most intensively applied herbicides worldwide, is commonly found in several water bodies, affecting the associated fauna. Autochthon crustacean species have been relatively less studied, compared to vertebrate species, particularly concerning reproductive success. In this mini-review, we summarize the relevant information about the effects of atrazine exposure on the main reproductive aspects of crustaceans. One of these effects is related to the inhibition of ovarian growth. In this respect, a diminished vitellogenin content was found in the ovary of crabs exposed to atrazine during the entire period of ovarian growth, in correlation with a reduced oocyte size and a delay of ovarian maturation. Similar results were observed in crayfish. Atrazine was also able to affect the reproductive process, acting as an endocrine disruptor. In this sense, this herbicide was suspected to affect the secretion of some neurohormones involved in the gonadal growth, as well as to alter the circulating levels of steroid hormones which promote the synthesis of vitellogenin for ovarian growth. Moreover, atrazine induced sexual differentiation in juvenile crayfish toward a higher proportion of females, while it produced an increment of males in daphnids. Another aspect affected by this herbicide was the reduction of offspring production, as well as several embryonic abnormalities; genotoxic effects have been also reported in crayfish. Finally, some metabolic imbalances, such as reduction in energy reserves, have been observed in some species, together with oxidative stress and histopathological effects.

Haemolymphatic Parameters in Two Aquaculture Crustacean Species Cherax destructor (Clark, 1836) and Cherax quadricarinatus (Von Martens, 1868)

Simple Summary

The spread of freshwater crustacean farms, in particular of the Australian species Cherax, has been widespread in recent years and has aroused particular interest at an economic level. Knowledge of the basic levels of some biochemical parameters becomes particularly important to understanding the health status of the animals and, therefore, for the maintenance of aquaculture facilities. In this study, the values of some biochemical parameters of two species of Cherax, Cherax destructor and Cherax quadricarinatus, reared in an Italian aquaculture plant, were evaluated for the first time. These parameters should contribute to assessing the health status of these animals on a farm and to understanding if they will be affected by stressful conditions or not.

Abstract

In the last few years, there has been a notable development in the breeding of freshwater shrimp (astaciculture), which involved various species and in particular, the two Australian Parastacidae species, Cherax destructor and Cherax quadricarinatus. Information about the haemolymphatic parameters of these two species is fragmentary, and filling these gaps becomes important given their importance in aquaculture. Cellular and biochemical parameters were analyzed in both species to create a reference baseline for these parameters to identify the state of welfare or suffering of these animals. The results showed that the total haemocyte count, haemocyte subpopulations, enzymatic activities and pH are similar between the two species, while total protein and osmolality are higher in C. destructor than C. quadricarinatus. Knowledge of these parameters could assist in evaluating the good health status of these species kept in aquaculture facilities.

The Effect of Zinc Concentration on Physiological, Immunological, and Histological Changes in Crayfish (Procambarus clarkii) as Bio-indicator for Environment Quality Criteria

The release of heavy metals to the environment increased dramatically with industrialization and rapid economic development, and they have accumulated in aquatic organisms. The current study aimed toe valuate the physiological, immunological, and histological changes of crayfish (Procambarus clarkii) as bio-indicator for water quality. Crayfishes of the filed study group were collected from a polluted area (Rosetta branch, Egypt), where the highest concentration for heavy metals in water was for zinc (Zn). Besides the field study group, other crayfishes were exposed to different doses of ZnSO₄ (0, 203, and 406 mg L^-g) corresponding to Zn concentration (0, 46.03, and 92.06 mg L^-1) respectively in aquariums for consecutive 4 days. Heavy metal concentrations in field water sample were arranged as follows: Zn > Fe> Pb > Cu and Mn > Ni > Co > Cd. The result revealed that Zn bioaccumulation increases significantly with the increase of water Zn concentration among the tested groups compared to the control group, where the highest bioaccumulation in all studied tissues (hepatopancreas, gills, and muscles) was observed in the field group and Zn high-dose group. Also, there was a significant increase in the levels of hemolymph uric acid, urea, creatinine, glucose, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. Their highest concentrations were observed in the Zn high-dose group and the field group, while the levels of total protein, albumin, and cholesterol showed a significant decrease among the tested groups as compared with the control group. Their determined lowest concentrations were in the Zn high-dose group and field group. Among tested groups, total hemocytes and granulated hemocytes decreased significantly while hyaline hemocytes increased as compared with the control group. Histological damages were observed in hepatopancreas, gills, and muscles in the field and Zn groups. The present study showed that exposure to Zn caused physiological and histological changes in Procambarus clarkia. We assumed that Procambarus clarkia could be used as a sensitive bioindicator for monitoring water quality criteria.

New insight on some selected nanoparticles as an effective adsorbent toward diminishing the health risk of deltamethrin contaminated water

Deltamethrin is a widely used insecticide that kills a wide variety of insects and ticks. Deltamethrin resistance develops as a result of intensive, repeated use, as well as increased environmental contamination and a negative impact on public health. Its negative impact on aquatic ecology and human health necessitated the development of a new technique for environmental remediation and wastewater treatment, such as the use of nanotechnology. The co-precipitation method was used to create Zn-Fe/LDH, Zn-AL-GA/LDH, and Fe-oxide nanoparticles (NPs), which were then characterized using XRD, FT-IR, FE-SEM, and HR-TEM. The kinetic study of adsorption test revealed that these NPs were effective at removing deltamethrin from wastewater. The larval packet test, which involved applying freshly adsorbed deltamethrin nanocomposites (48 hours after adsorption), and the comet assay test were used to confirm that deltamethrin had lost its acaricidal efficacy. The kinetics of the deltamethrin adsorption process was investigated using several kinetic models at pH 7, initial concentration of deltamethrin 40 ppm and temperature 25°C. Within the first 60 min, the results indicated efficient adsorption performance in deltamethrin removal, the maximum adsorption capacity was 27.56 mg/L, 17.60 mg/L, and 3.06 mg/L with the Zn-Al LDH/GA, Zn-Fe LDH, and Fe Oxide, respectively. On tick larvae, the results of the freshly adsorbed DNC bioassay revealed larval mortality. This suggests that deltamethrin's acaricidal activity is still active. However, applying DNCs to tick larvae 48 hours after adsorption had no lethal effect, indicating that deltamethrin had lost its acaricidal activity. The latter result corroborated the results of the adsorption test's kinetic study. Furthermore, the comet assay revealed that commercial deltamethrin caused 28.51% DNA damage in tick cells, which was significantly higher than any DNC. In conclusion, the NPs used play an important role in deltamethrin decontamination in water, resulting in reduced public health risk. As a result, these NPs could be used as a method of environmental remediation.

A Comprehensive Review on Crustaceans' Immune System With a Focus on Freshwater Crayfish in Relation to Crayfish Plague Disease

Freshwater crayfish immunity has received great attention due to the need for urgent conservation. This concern has increased the understanding of the cellular and humoral defense systems, although the regulatory mechanisms involved in these processes need updating. There are, however, aspects of the immune response that require clarification and integration. The particular issues addressed in this review include an overall description of the oomycete Aphanomyces astaci, the causative agent of the pandemic plague disease, which affects freshwater crayfish, and an overview of crustaceans' immunity with a focus on freshwater crayfish. It includes a classification system of hemocyte sub-types, the molecular factors involved in hematopoiesis and the differential role of the hemocyte subpopulations in cell-mediated responses, including hemocyte infiltration, inflammation, encapsulation and the link with the extracellular trap cell death pathway (ETosis). In addition, other topics discussed include the identity and functions of hyaline cells, the generation of neoplasia, and the emerging topic of the role of sessile hemocytes in peripheral immunity. Finally, attention is paid to the molecular execution of the immune response, from recognition by the pattern recognition receptors (PRRs), the role of the signaling network in propagating and maintaining the immune signals, to the effector elements such as the putative function of the Down syndrome adhesion molecules (Dscam) in innate immune memory.

Chronic ciprofloxacin and atrazine co-exposure aggravates locomotor and exploratory deficits in non-target detritivore speckled cockroach (Nauphoeta cinerea)

The global detection of ciprofloxacin and atrazine in soil is linked to intensive anthropogenic activities in agriculture and inadvertent discharge of industrial wastes to the environment. Nauphoeta cinerea is a terrestrial insect with cosmopolitan distribution and great environmental function. The current study probed the neurobehavioral and cellular responses of N. cinerea singly and jointly exposed to atrazine (1.0 and 0.5 μg g^-1 feed) and ciprofloxacin (0.5 and 0.25 μg g^-1 feed) for 63 days. Results demonstrated that the reductions in the body rotation, maximum speed, turn angle, path efficiency, distance traveled, episodes, and time of mobility induced by atrazine or ciprofloxacin per se was exacerbated in the co-exposure group. The altered exploratory and locomotor in insects singly and jointly exposed to ciprofloxacin and atrazine were verified by track plots and heat maps. Furthermore, we observed a decrease in acetylcholinesterase and anti-oxidative enzyme activities with concomitant elevation in the levels of lipid peroxidation, nitric oxide, and reactive oxygen and nitrogen species were significantly intensified in the midgut, hemolymph, and head of insects co-exposed to ciprofloxacin and atrazine. In conclusion, exposure to binary mixtures of ciprofloxacin and atrazine elicited greater locomotor and exploratory deficits than upon exposure to the individual compound by inhibiting acetylcholinesterase activity and induction of oxido-inflammatory stress responses in the insects. N. cinerea may be a usable model insect for checking contaminants of ecological risks.

Use of nontarget organism Chironomus sancticaroli to study the toxic effects of nanoatrazine

Atrazine was banned by the European Union in 2004, but is still used in many countries. Agricultural research employing nanotechnology has been developed in order to reduce the impacts to the environment and nontarget organisms. Nanoatrazine was developed as a carrier system and have been considered efficient in weed control. However, its toxicity must be verified with nontarget organisms. In this context, the aim of the present study was to investigate ecotoxicological effects of solid lipid nanoparticles (empty and loaded with atrazine) and atrazine on Chironomus sancticaroli larvae, evaluating the endpoints: mortality, mentum deformity, development rate and biochemical biomarkers. The contaminant concentrations used were 2, 470, 950, and 1900 μg L^-1 in acute (96 h) and 2 μg L^-1 in subchronic (10 days) bioassays. An environmentally relevant concentration of atrazine (2 μg L^-1) presented toxic and lethal effects towards the larvae. The nanoparticles loaded with atrazine showed toxic effects similar to free atrazine, causing mortality and biochemical alterations on the larvae. The nanoparticle without atrazine caused biochemical alterations and mortality, indicating a possible toxic effect of the formulation on the larvae. In the acute bioassay, most concentrations of nanoparticles loaded with atrazine were not dose dependent for the endpoint mortality. Only the atrazine concentration of 470 μg L^-1 was statistically significant to endpoint mentum deformity. The atrazine and nanoparticles (with and without atrazine) did not affect larval development. The results indicate that Chironomus sancticaroli was sensitive to monitor nanoatrazine, presenting potential to be used in studies of toxicity of nanopesticides.

Effect of maduramicin on crayfish (Procambius clarkii): Hematological parameters, oxidative stress, histopathological changes and stress response

Maduramicin, an extensively used anticoccidial drug, has been introduced into environment due to poorly absorbed in the intestine of broiler chicken. To understand the potential ecological toxicity of maduramicin on aquatic organisms, acute and subacute toxicity, hemolymph biochemistry, histopathology and the expressions of drug metabolism and stress response genes of crayfish (Procambius clarkii) were investigated in this study. For the first time, the 96 h median lethal concentration (LC₅₀) of maduramicin on crayfish was 67.03 mgL^-1 with a 95% confidence interval (54.06-81.32 mgL^-1). Then, the crayfish were exposed to 0.7 mgL^-1 (1/100 LC₅₀), 3.5 mgL^-1 (1/20 LC₅₀) and 7.0 mgL^-1 (1/10 LC₅₀) maduramicin for 28 days. Maduramicin significantly altered biochemical parameters including AST, ALT, CK, LDH and ALP of hemolymph in crayfish at several time points. The activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) of crayfish gills, hepatopancreas and abdominal muscle were significantly decreased or elevated by different concentrations of maduramicin treatment at varying time points. Furthermore, histopathological damage of crayfish gills, hepatopancreas and abdominal muscle were observed in a concentration-dependent manner. The expressions of metabolic and stress response genes (CYP450, GST, COX1, COX2, HSP70 and MT) in hepatopancreas of crayfish were significantly up-regulated by maduramicin (7.0 mgL^-1) treatment for 8 h to 7 d, and returned to normal levels after the removal of maduramicin for 3-7 days. In conclusion, our findings demonstrated that environmental exposure of maduramicin threaten to the health of crayfish living in the areas nearby livestock farms or pharmaceutical factory. Crayfish exhibited resistance to the stress of maduramicin via activating drug metabolite and detoxification pathways.

Rapid uptake of atrazine from aqueous phase by thermally activated MCM-41

This study was designed to prepare an adsorbent without any complex modification process for the removal of atrazine (AZN) from aqueous phase. Thus, Mobil composition of matter No. 41 (MCM-41) was synthesized and modified by physical activation at high temperature (650 °C). The synthesized adsorbent was tested by XRD, SEM, EDX, FT-IR and BET to confirm the successful synthesis as well as effectiveness for the adsorption of AZN. The average particle size of prepared material was found to be about 500 nm, while the BET calculations showed that adsorbent was porous with a specific surface area of 25.9 m²/g. Later, it was used in batch removal studies of AZN for which, it showed a high adsorption capacity of 89.99 (mg/g). The pH of 6, temperature of 313 K was found to be the optimized conditions for the maximum removal of AZN. Of the four kinetic models studied, the pseudo-first-order yielded a superior fit in comparison with the other three models. The results indicated that the five linearized adsorption equilibrium isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Harkins-Jura models) closely correlate the AZN adsorption removal process with Pearson correlation coefficient (R²) values of 0.9955, 0.8551, 0.8736, 0.8913 and 0.7253, respectively. The energy functions obtained by thermodynamic analysis suggested that the AZN sorption follows a non-spontaneous and endothermic path.

The effect of chronic exposure to chloridazon and its degradation product chloridazon-desphenyl on signal crayfish Pacifastacus leniusculus

The effects of chloridazon (Ch) and its metabolite chloridazon-desphenyl (Ch-D) at the environmentally relevant concentrations of 0.45 µg/L and 2.7 µg/L on signal crayfish Pacifastacus leniusculus were assessed in a 30-day exposure followed by a 15-day depuration period. Locomotion, biochemical haemolymph profile, oxidative and antioxidant parameters, and histopathology were evaluated. Crayfish exposed to Ch at 0.45 µg/L and 2.7 µg/L showed significantly (p < 0.01) higher CAT activity and GSH level in hepatopancreas and gill compared to controls. The concentration of Ch at 2.7 µg/L was associated with significantly (p < 0.01) higher levels of GLU, LACT, ALT, AST in haemolymph compared to controls. Chloridazon-desphenyl exposure at both tested concentrations caused significantly higher (p < 0.01) GLU, LACT, ALT, AST, NH₃, and Ca in haemolymph; lipid peroxidation (TBARS) levels in hepatopancreas; and CAT activity and GSH level in hepatopancreas and gill. Alterations of structure including focal dilatation of tubules, increased number of fibrillar cells, and haemocyte infiltration in the interstitium were observed with 2.7 µg/L Ch and with both Ch-D exposures. Locomotion patterns did not vary significantly among groups. A 15-day recovery period was insufficient to restore normal physiological parameters in exposed groups. Chloridazon and its metabolite Ch-D exerts harmful effects on crayfish.

Combined effects of exposure to sub-lethal concentration of the insecticide chlorpyrifos and the herbicide glyphosate on the biochemical changes in the freshwater crayfish Pontastacus leptodactylus

Glyphosate is an herbicide that inhibits the growth of weed plants, while chlorpyrifos is an insecticide commonly applied to control the pests' population. This study aimed to investigate the combined effects of chlorpyrifos and glyphosate on biochemical, immunological parameters, and oxidative stress biomarkers in freshwater crayfish Pontastacus leptodactylus for 21 days. The experimental design of this study was factorial (3 × 3), including 0.0, 0.4, and 0.8 mg L-1 glyphosate and 0.0, 2.5, and 5 µg L-1 chlorpyrifos. The exposure to chlorpyrifos, glyphosate alone and a mixture of them significantly decreased acetylcholinesterase, alkaline phosphatase, phenoloxidase activities, and total protein levels. The lactate dehydrogenase, glutamic-pyruvic-transaminase, and catalase activities, the contents of glucose, and malondialdehyde levels were increased in the crayfish. No significant changes were detected in glutamic-oxaloacetic-transaminase (SGOT) activity, triglyceride, and total antioxidant (TAO) levels in the crayfish treated with 0.4 mg L-1 glyphosate and the control group. Co-exposure of crayfish to chlorpyrifos and glyphosate increased SGOT activity and TAO levels. Although chlorpyrifos combined with glyphosate decreased the γ-Glutamyltransferase (GGT) activity, the GGT activity was significantly increased in the P. leptodactylus exposed during 21 days to 5 µg L-1 chlorpyrifos alone and 0.8 mg L-1 glyphosate alone. In comparison with the reference group, no significant changes were evidenced in the cholesterol levels in the P. leptodactylus treated with 2.5 µg L-1 chlorpyrifos, but its levels were significantly increased in the other treatment groups. In conclusion, the mix of glyphosate and chlorpyrifos exhibited synergic effects on the different toxicological biomarkers in the narrow-clawed crayfish. Co-exposure to pesticides may result in disruption of homeostasis in the crayfish by altering the biochemical and immunological parameters.

Single and combined effects of thiacloprid concentration, exposure duration, and water temperature on marbled crayfish Procambarus virginalis

The increasing utilization of chemicals and ongoing climate change have a negative impact on aquatic ecosystems. The present study examined combined effects of water temperature, chemical concentration, and duration of exposure to the neonicotinoid thiacloprid on marbled crayfish Procambarus virginalis. Crayfish were exposed to thiacloprid at the environmental concentration of 4.50 μg L-1 and 10% 96LC50 to marbled crayfish, 64.64 μg L-1, at water temperature of 17 and 23 °C for 28 days followed by a 28 day depuration period. No crayfish died during the experiment. Both thiacloprid concentrations at 23 °C showed a synergistic effect with temperature on the biochemical indicators in haemolymph compared to those at 17 °C. Both concentrations of thiacloprid at both temperatures were associated with significant differences from thiacloprid-free controls (P < 0.01) in haemolymph glucose, ammonia, calcium, inorganic phosphate, and lactate; haemolymph enzymes aspartate aminotransferase, alanine aminotransferase, creatine kinase, and alkaline phosphatase; antioxidant biomarkers superoxide dismutase, catalase, glutathione S-transferase, and reduced glutathione in hepatopancreas, muscle, and gill, and showed lipid peroxidation in hepatopancreas and muscle. Histological analyses revealed structural changes and damage to gill and hepatopancreas of exposed crayfish.

Comprehensive fitness evaluation of common carp (Cyprinus carpio L.) after twelve weeks of atrazine exposure

Atrazine is frequently detected in surface waters and negatively affect physiological function in aquatic organisms. Even though numerous authors have intensively studied its toxicity, only limited information concerning the long-term fish exposure is available. The aim of this study was evaluation of chronic exposure in common carp. Fish were exposed to a range of atrazine concentrations (0.3 - environmentally relevant concentration; 300; 1000; and 3000 µg/l) for twelve weeks. The potential impact of atrazine exposure was studied using various markers (behaviour; biometrical characteristics; haematological, biochemical and oxidative stress indices and histopathological changes). Most alterations were recorded at the highest concentration (3000 µg/l) which is probably due to a combined effect of both the herbicide exposure and intensive parasite infection development during second week. This group was cancelled after three weeks due to adverse health status, which partly confirmed atrazine immunotoxicity. Chronic exposure resulted in long-term reduction in feed intake followed by a significant decrease in body weight and morphological changes in gill at 1000 µg/l. At the same concentration, significant alterations in haematological (e.g. increase in erythrocyte, leukocyte, lymphocytes and neutrophil counts as well as decrease in monocyte counts) and biochemical (e.g. changes in enzyme activities; increase in glucose; decrease in ammonia) indices were documented, especially during first three weeks. Similar trend, but not so intensive, was observed at 300 µg/l. Moreover, significant changes were observed in various indicators of oxidative stress. These alterations were highly variable with both increasing and decreasing trends depending on dose and analysed tissue. Significant changes, especially in white blood profile, enzyme activities and oxidative stress indices, were proven even at 0.3 µg/l. Obtained results indicate that chronic atrazine exposure of common carp can negatively influence many indicators of health status such as behaviour, immune response, haematological and biochemical profile, oxidative stress indices and organ histopathology.

Effects of metazachlor and its major metabolite metazachlor OA on early life stages of marbled crayfish

The effects of the herbicide metazachlor and its major metabolite metazachlor OA at two concentrations, including environmentally relevant concentrations of metazachlor (0.0115 µmol/l and 0.0790 µmol/l) and metazachlor OA (0.0117 µmol/l and 0.0805 µmol/l), respectively, were evaluated on early ontogeny, growth, behaviour, oxidative stress, antioxidant enzyme levels, histology, and mortality of marbled crayfish Procambarus virginalis. Both tested concentrations of metazachlor and metazachlor OA were associated with significantly lower growth and delayed ontogenetic development compared to controls. Exposure of metazachlor at 0.0115 µmol/l and metazachlor OA at 0.0117 µmol/l and 0.0805 µmol/l resulted in significantly lower activity of total superoxide dismutase (SOD), catalase (CAT), glutathione s-transferase (GST), glutathione reductase (GR), and reduced glutathione (GSH) compared with control and resulted in gill anomalies ranging from wall thinning to focal disintegration of branchial structure. Metazachlor at the environmentally relevant concentration of 0.0790 µmol/l was associated with significant alterations of crayfish distance moved and walking speed. The potential risk associated with metazachlor use in agriculture related to effects on non-target aquatic organisms.

An overview of the potential impacts of atrazine in aquatic environments: Perspectives for tailored solutions based on nanotechnology

Atrazine is a pre- and post-emergence herbicide used to control weeds in many crops. It was introduced in the late 1950s, but its use has been controversial because of its high potential for environmental contamination. In agriculture, the implementation of sustainable practices can help in reducing the adverse effects atrazine. This review addresses aspects related to the impacts of atrazine in the environment, with focus on its effects on aquatic species, as well as the potential use of nanoencapsulation to decrease the impacts of atrazine. The application of atrazine leads to its dispersal beyond the immediate area, with possible contamination of soils, sediments, plantations, pastures, public supply reservoirs, groundwater, streams, lakes, rivers, seas, and even glaciers. In aquatic ecosystems, atrazine can alter the biota, consequently interfering in the food chains of many species, including benthic organisms. Nanoformulations loaded with atrazine have been developed as a way to reduce the adverse impacts of this herbicide in aquatic and terrestrial ecosystems. Ecotoxicological bioassays have shown that this nanoformulations can improve the targeted delivery of the active ingredient, resulting in decreased dosages to obtain the same effects as conventional formulations. However, more detailed analyses of the ecotoxicological potential of atrazine-based nanoherbicides need to be performed with representative species of different ecosystems.

Cytochrome P450 and Glutathione-S-Transferase Activity are Altered Following Environmentally Relevant Atrazine Exposures in Crayfish (Faxoniusvirilis)

The herbicide atrazine is heavily applied in the U.S. Midwest to control broadleaf weeds. It enters local streams and rivers through runoff and seepage, and exposure can affect non-target aquatic organisms, like crayfish. We examined sublethal effects of atrazine on the expression and activity of the detoxification enzymes cytochrome P450 (CYP450) and glutathione-S-transferase (GST) in crayfish. Crayfish were exposed to 0, 10, 40, 80, 100 and 300 ppb atrazine for 1, 2, 4, 7 and 10 days. Their hepatopancreas was collected and CYP450 expression and GST activity was analyzed. Atrazine exposure caused differential expression and activity of CYP450 and GST. CYP450 expression varied over exposure concentrations and time. Further, GST activity significantly increased following a 2 day, 10 ppb exposure to atrazine and a 300 ppb atrazine exposure for all days tested. We found that atrazine detoxification is a dynamic process that changes with the length and intensity of atrazine exposure.

Effects of pollution on freshwater aquatic organisms

This paper presents the reviews of scientific papers published in 2018 issues on the effects of anthropogenic pollution on the aquatic organisms dwelling in freshwater ecosystem at global scale. The first part of the study provides the summary of relevant literature reviews followed by field and survey based studies. The second part is based on categories of different classes/sources of pollutants which affect freshwater organism. This is composed of several sections including metals and metalloids, wastewater and effluents, sediments, nutrients, pharmaceuticals, polycyclic aromatic hydrocarbons, flame retardants, persistent organic pollutants, pharmaceuticals and illicit drugs, emerging contaminants, pesticides, herbicides, and endocrine disruptors. The final part of the study highlights the reviews of published research work on new pollutants such as microplastics and engineered nanoparticles which affect the freshwater organisms. PRACTITIONER POINTS: Heavy metals concentrations should be assessed at nano-scale in aquatic environment. Air pollutants could have long-term effects on freshwater ecosystem. Future studies should focus on bioremediations of freshwater pollution.

Acute exposure to chlorpyrifos and glyphosate induces changes in hemolymph biochemical parameters in the crayfish, Astacus leptodactylus (Eschscholtz, 1823)

Acute and subacute toxicity tests for chlorpyrifos and glyphosate were performed on the crayfish, Astacus leptodactylus. The crayfish were divided into a control group and four experimental groups with exposure from 50.18 to 301.11 μg L-1 of chlorpyrifos for 96 h under semi-static test conditions. In the same experiment, the crayfish were exposed to different concentrations of glyphosate (from 0.0, 8.14 to 13.05 mg L-1) for 96 h. Mortality was recorded, and the median lethal concentrations (LC50) were calculated using probit analysis. The 96 h LC50 values of chlorpyrifos and glyphosate to A. leptodactylus were 49.55 ± 4.66 μg L-1 and 7.83 ± 0.50 mg L-1, respectively. The results showed that chlorpyrifos was a few hundred times more toxic than glyphosate for the crayfish. Then, the crayfish were exposed to different subacute concentrations of chlorpyrifos (12.5 and 25 μg L-1) and glyphosate (2 mg L-1 and 4 mg L-1) for seven days, and their toxicity was evaluated through several hemolymph biochemical parameters. Chlorpyrifos and glyphosate exposure caused a significant (P < 0.01) increase in the activity of lactate dehydrogenase (LDH), and gamma-glutamyl transferase (GGT). The results showed a significant (P < 0.01) decrease in acetylcholinesterase (AChE), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and phenoloxidase (PO) activities in the hemolymph of the crayfish exposed to chlorpyrifos and glyphosate. The total protein and cholesterol levels showed a significant decrease (P < 0.01) in the hemolymph of the crayfish after seven days of exposure to chlorpyrifos and glyphosate. There was a significant increase in triglycerides and glucose levels in treated crayfish. These results show that chlorpyrifos is highly toxic, while glyphosate is moderately toxic to A. leptodactylus. According to the results, subacute concentrations of chlorpyrifos and glyphosate could lead to a collapse of cellular homeostasis and changes in the hemolymph biochemical parameters in the crayfish. Physiological changes caused by exposure to chlorpyrifos and glyphosate in A. leptodactylus may have direct effects on the survival of these organisms.

Effects of atrazine on life parameters, oxidative stress, and ecdysteroid biosynthetic pathway in the marine copepod Tigriopus japonicus

Atrazine is a widely used pesticide which acts as an endocrine disruptor in various organisms. The aim of this study was to investigate adverse effects of atrazine on life parameters, oxidative stress, and ecdysteroid biosynthetic pathway in the marine copepod Tigriopus japonicus. In T. japonicus, no mortality was shown in response to atrazine up to 20 mg/L in acute toxicity assessment. In nauplii, retardation in the growth and prolonged molting and metamorphosis resulted under chronic exposure of atrazine at 20 mg/L. In addition, body sizes of T. japonicus nauplii were significantly decreased (P < 0.01 in length and P < 0.001 in width) in response to 20 mg/L of atrazine. Furthermore, atrazine induced oxidative stress by the generation of reactive oxygen species at all concentrations compared to the control in the nauplii. Also, significant increase in glutathione-S transferase activity was observed in adult T. japonicus at low concentration of atrazine. To understand effects of atrazine on ecdysteroid biosynthetic pathway-involved genes (e.g., neverland, CYP307E1, CYP306A1, CYP302A1, CYP3022A1 [CYP315A1], CYP314A1, and CYP18D1) were examined with mRNA expressions of ecdysone receptor (EcR) and ultraspiracle (USP) in response to 20 mg/L atrazine in nauplii and adults. In the nauplii, these genes were significantly downregulated (P < 0.05) in response to atrazine, compared to the control but not in the adult T. japonicus. These results suggest that atrazine can interfere in vivo life parameters by oxidative stress-induced retrogression and ecdysteroid biosynthetic pathway in this species.

Effects of S-metolachlor and its degradation product metolachlor OA on marbled crayfish (Procambarus virginalis)

Increasing production of energy crops in Europe, mainly maize and rapeseed, has altered patterns of pesticide use in recent decades. The long-term effects of S-metolachlor (S-M) and of its metabolite metolachlor OA (M-OA) at the environmentally relevant concentration of 4.2 μg L^-1 and at 42 μg L^-1 (ten-fold concentration) on marbled crayfish (Procambarus virginalis) were evaluated in a 28-day exposure and after a subsequent 28-day recovery period. Indicators assessed were behaviour; biochemical haemolymph profile; oxidative and antioxidant parameters of gill, hepatopancreas, and muscle; and histology of hepatopancreas and gill. Results showed biochemical haemolymph profile (lactate, alanine aminotransferase, aspartate aminotransferase, inorganic phosphate), lipid peroxidation in hepatopancreas, and antioxidant parameters (catalase, reduced glutathione, glutathione S-transferase) of hepatopancreas and gill of crayfish exposed to S-M and M-OA to significantly differ from controls (P < 0.01). Antioxidant biomarker levels remained different from controls after a 28-day recovery period. Differences in behaviour including speed of movement and velocity, and histopathological damage to gill and hepatopancreas were associated with S-M and M-OA exposure and persisted after 28 days in S-M- and M-OA-free water. Results suggest harmful effects of low concentrations of S-M and its metabolite M-OA on non-target organisms and provide information for assessing their effects at environmentally relevant concentrations.