Effects Of Atrazine Research Articles

The effect of atrazine on intestinal histology, microbial community and short chain fatty acids in Pelophylax nigromaculatus tadpoles

The intestine is the main organ for nutrient absorption in amphibians. It is sensitive to atrazine, which is a herbicide widely used in agricultural areas. At present, there is a lack of systematic research on the effect of atrazine on the amphibian intestine. In this study, we evaluated the effects of atrazine exposure (0, 50 μg/L, 100 μg/L, and 500 μg/L) for 20 days on intestinal histology, microbiota and short chain fatty acids in Pelophylax nigromaculatus tadpoles. Our research showed that 500 μg/L atrazine exposure significantly decreased the height of microvilli and epithelial cells, and altered the composition and diversity of intestinal microbiota in P. nigromaculatus tadpoles compared to the control. At the phylum level, the abundance of Bacteroidetes and Fusobacteria increased significantly, while that of Verrucomicrobia and Firmicutes decreased significantly in the 500 μg/L atrazine treatment group. At the genus level, Akkermansia and Lactococcus had significantly lower abundance in the 100 μg/L and 500 μg/L atrazine exposure group, while Cetobacterium was only detected in the 100 μg/L and 500 μg/L atrazine treated group. Also, function prediction of intestinal microbiota showed that atrazine treatment significantly changed the metabolism pathways of P. nigromaculatus tadpoles. In addition, 500 μg/L atrazine exposure changed the content of short chain fatty acids by significantly increasing the content of total SFCAs, butyric acid, and valeric acid, and decreasing the content of isovaleric acid in the intestine. Taken together, atrazine exposure could affect the intestinal histology and induce intestinal microbiota imbalance and metabolic disorder in amphibian tadpoles.

Dynamic Response of Soil Enzymes and Microbial Diversity to Continuous Application of Atrazine in Black Soil of a Cornfield without Rotation in Northeast China

Atrazine has been extensively used in China’s agricultural production for a long time and the potential risks to the environment have received widespread attention. The purpose of this study was to examine the effect of the continuous application of atrazine on soil herbicide residues, soil enzyme activity, and microbial community structure, as well as to provide a theoretical reference for the appropriate application of atrazine and the improvement of soil. Previous studies have focused on the effects of atrazine on soil microorganisms, but the experiments used higher doses than recommended. To reveal the actual effects of atrazine on soil microorganisms, the recommended dose of atrazine was used for 0, 1, and 2 years. We studied atrazine residues and enzyme activity in the soil, and phospholipid fatty acids (PLFA) were measured to study the structure of the soil microbiome. The results show that the rate of atrazine degradation occurred rapidly after the initial administration, and with the increase in continuous administration, its half-life decreased from 24.6 d in the first year to 14.1 d in the second year. The application of atrazine significantly affected soil urease activity and cellulase activity, but it had no significant effect on saccharase activity. The continuous application of atrazine had a significant effect on the biomass of cultured bacteria in soil, but not on the biomass of culturable fungi and actinomycetes in the soil. Furthermore, the results of PLFA analysis show that the application of atrazine had a significant effect on the microbial structure of the soil. These results indicate that the significant increase in the degradation rate of atrazine during continuous application is related to the high adaptability of the soil microbiome.

Facile synthesis of modified carbon nitride with enhanced activity for photocatalytic degradation of atrazine

The extensive usage of atrazine constitutes a risk for water environment due to its great mobility, long half-life and low biodegradability, which could further cause residual injury to the succeeding crops. Therefore, the efficient removal of atrazine in water environment is an important measure to control its risk. In this study, modified carbon nitride (TEA-CN-30) was synthesized based on a facile photochemical reduction method with the assistant of triethanolamine and applied for atrazine photocatalytic degradation. The photocatalytic performance was significantly improved compared to bulk graphitic carbon nitride (g-C3N4). Almost 90% atrazine degradation was achieved in just an hour. The possible degradation pathways were dealkylation, hydroxylation, and dechlorination based on intermediates analyzing. Besides, the germination inhibition effect of atrazine on wheat seeds was reduced after photodegradation by TEA-CN-30. TEA-CN-30 was also capable of simultaneously removing 10 other commonly used pesticides, including insecticides, herbicides, and fungicides. This work implies promising applications of TEA-CN-30 in alleviating negative effects of multi-pesticides on environment.

The Atrazine Saga and its Importance to the Future of Toxicology, Science, and Environmental and Human Health

The herbicide atrazine is one of the most commonly used, well studied, and controversial pesticides on the planet. Much of the controversy involves the effects of atrazine on wildlife, particularly amphibians, and the ethically questionable decision making of members of industry, government, the legal system, and institutions of higher education, in most cases in an effort to "bend science," defined as manipulating research to advance economic, political, or ideological ends. In this Critical Perspective I provide a timeline of the most salient events in the history of the atrazine saga, which includes a multimillion-dollar smear campaign, lawsuits, investigative reporting, accusation of impropriety against the US Environmental Protection Agency, and a multibillion-dollar transaction. I argue that the atrazine controversy must be more than just a true story of cover-ups, bias, and vengeance. It must be used as an example of how manufacturing uncertainty and bending science can be exploited to delay undesired regulatory decisions and how greed and conflicts of interest-situations where personal or organizational considerations have compromised or biased professional judgment and objectivity-can affect environmental and public health and erode trust in the discipline of toxicology, science in general, and the honorable functioning of societies. Most importantly, I offer several recommendations that should help to 1) prevent the history of atrazine from repeating itself, 2) enhance the credibility and integrity of science, and 3) enrich human and environmental health. Environ Toxicol Chem 2021;40:1544-1558. © 2021 SETAC.

Effects of atrazine on the endocrinology and histoarchitecture of the testes in African Catfish, Clarias gariepinus (Burchell, 1822)

Aquatic ecosystems often receive a wide spectrum of pollutants introduced directly or indirectly. The herbicide atrazine, an endocrine disrupting chemical (EDC), frequently contaminates potable water supplies and aquatic ecosystems. Studies suggest atrazine induced alterations in the neuroendocrine system along the hypothalamus-pituitary-gonadal (HPG) axis. This study investigated the effects of atrazine (0, 2.5, 25, 250 and 500 μg l−1 for 28 days of exposure) on testosterone (TST) and prolactin (PRL) levels, testes histology and seminiferous tubular morphometry of Clarias gariepinus juveniles. TST and PRL significantly decreased in all the 28 days atrazine exposed groups. Histologically, the testes showed vacuolated and sloughing of basal germinal epithelium in the treated groups. A high correlation between testicular biopsy score counts and results of seminiferous tubular morphometry was also observed. Findings from this study confirm that atrazine is an EDC in fish that alters reproductive dysfunction by targeting the HPG axis, as evidenced by its effects on the investigated reproductive hormones. Furthermore, atrazine disrupted the histoarchitectural components of the testes, which may interfere with spermatogenesis and therefore impair the reproductive functions of the fish.

Short-term lethal and sublethal atrazine effects on Litoditis marina: towards a nematode model for marine toxicity assessment?

Organochlorine pesticides are still widely used in many regions of the world, despite their toxic properties to many organisms, including humans, and their high environmental persistence in waters and sediments. In order to properly assess contaminant effects across trophic levels in aquatic communities, the responses of different model organisms should be investigated. Particularly for marine benthic environments, relatively few model organisms for the assessment under controlled laboratory conditions of both lethal and sublethal effects are available. Here we investigate the use of a cryptic species of the free-living nematode Litoditis marina as a model organism for short-term tests of the impacts of contaminants, using the case of the herbicide atrazine. Its ease of culturing, short generation time and high fecundity render L. marina PmIII a good candidate to assess contaminant effects for both a rapid assessment of impacts and more detailed investigations of the mechanisms behind those effects. The LC50 of atrazine to adult L. marina PmIII was 3.3 ± 0.5 mg/L after a 5-day exposure, suggesting a comparatively higher sensitivity of this species compared to other aquatic invertebrate model species, mainly crustaceans. This LC50 was less than half the value after a 4-day exposure and was 22-fold lower than the 48 h LC50, demonstrating the importance of performing lethality tests for as long an exposure time as possible. Sublethal effects were observed at much lower atrazine concentrations and encompassed, from 0.8 mg/L onwards, impairment of life-history traits (reduced fecundity and extended egg deposition and development times) and population parameters (abundances of juveniles and adults, adult sex ratio). These sublethal effects were broadly consistent among different life-history traits and population parameters, but fecundity and the maximum abundances of juveniles, adults and total nematodes were the most sensitive response variables. We therefore suggest that an adequate assessment of sublethal contaminant effects on L. marina requires a combination of different life-history traits and population-level parameters. We conclude that L. marina PmIII is a suitable model species for ecotoxicological research encompassing both lethal and sublethal effects, and can as such contribute to environmental risk assessment in marine and estuarine systems.

EFIKASI HERBISIDA ATRAZIN TERHADAP PERTUMBUHAN GULMA DAN TANAMAN SERTA HASIL TANAMAN JAGUNG (Zea mays L.)

One of the herbicides that can be used to control weeds on corn cultivation is the atrazine herbicide. The aim of this study was to determine the effectiveness of atrazine in controlling weeds in corn, to determine whether there was a change in the composition of weeds in corn after application of the atrazine, and to determine whether the use of atrazine herbicide could cause phytotoxicity and inhibit growth and reduce corn yield. The research was conducted on farmer's land in Hajimena Village, Natar District, South Lampung Regency and Weed Laboratory, Faculty of Agriculture, University of Lampung from November 2019 to March 2020. The research was arranged in a randomized complete block design (RCBD) with four replications and six treatments, namely the herbicide atrazine doses of 1,20 kg/ha,1,80 kg/ha, 2,40 kg / ha, 3,00 kg / ha, manual weeding, and control. The results showed that atrazine herbicide doses of 1,20-3,00 kg/ha were effective to control of weeds total on corn area up to 6 weeks after application, atrazine herbicide caused change on weed composition of Richardia brasiliensis become Calopogonium mucunoides at 3 and 6 weeks after application, and the application of atrazine herbicide doses of 1,20–3,00 kg/ha did not cause phytotoxicity, inhibit corn growth, and decrease yields. Keywords: atrazine, weed, herbicide, corn

Toxicity of Atrazine to Marine Invertebrates Under Flow-Through Conditions\u2014Eastern Oyster (Crassostrea virginica) and Mysid Shrimp (Americamysis bahia)

The triazine herbicide atrazine is routinely detected in freshwaters, and has also been detected in coastal waters in Europe and the US. Relatively few atrazine studies have been conducted with estuarine/marine invertebrates. This study sought to contribute additional invertebrate atrazine toxicity data using model species, Eastern oyster (Crassostrea virginica) and Mysid shrimp (Americamysis bahia). Specifically, we investigated (1) acute effects on survival and growth of Eastern oyster, and (2) acute and chronic effects on survival, reproduction, and growth of the Mysid shrimp. No oyster mortality was observed following 96-h exposure to up to 17 mg a.i./L, but shell growth was reduced by 0.55% to 16% in 1.0, 9.2, and 17 mg a.i./L treatments, resulting in a 96-h EC50 of > 17 mg a.i./L. In the 96-h Mysid test, mortality rates of 5 to 70% were observed in 1.7, 2.4, 3.6, and 6.4 mg a.i./L treatments, and the 96-h LC50 was 5.4 mg a.i./L. Sub-lethal effects were observed among surviving Mysids exposed to ≥ 2.4 mg a.i./L. After 28 days of exposure to up to 1.1 mg a.i./L, there were no effects on survival or reproduction. The LOEC was 0.50 mg a.i./L, based on reduced body size, and the NOEC was 0.26 mg a.i./L. Overall, the results indicate that atrazine is slightly toxic towards Eastern oyster and moderately toxic to the Mysid shrimp under acute exposure conditions. These data will help to fill a gap in the literature and inform risk assessment of potential effects of atrazine towards estuarine/marine communities.

Effect of atrazine on accumulation of iron via the iron transport proteins in the midbrain of SD rats.

Atrazine (ATR), a widely used herbicide that belongs to the triazine class, has detrimental effects on several organ systems. It has also been shown that ATR exposure results in dopaminergic neurotoxicity. However, the mechanism of herbicides causing ferroptosis in neurons is less concerned. So, the present study aimed to investigate the effects of long-term oral exposure to ATR on ferroptosis in adult male rats. In this study, we show that there was a dose-dependent increase in the concentration of iron in the midbrain. Simultaneously, the expression of tyrosine hydroxylase (TH) and Synuclein (α-syn) were altered by the ATR. We carried out miRNA profiling brain tissue in order to identify factors that mediate ferroptosis. We also found that the mRNA and protein expression of the transferrin receptor (TFR), divalent metal transporter 1 (DMT1), hephaestin (HEPH), and ferroportin 1 (Fpn1) in the midbrain were affected by ATR. Based on the current results and previously published data, it is clear that exposure of adult male rats to high doses of ATR leads to iron loading in the midbrain. The long-term adverse effects of ATR on the midbrain have a special relevance after exposure.

Atrazine impairs testicular function in BalB/c mice by affecting Leydig cells

Several studies have reported the effects of atrazine on the gonads of many experimental models. However, the short-term effects of in vivo exposure to atrazine on the testes of mice are not well clarified. Here we reported that adult BalB/c mice exposed to atrazine (50 mg kg−1 body weight) by gavage for three consecutive days have reduced numbers of 3β-hydroxysteroid dehydrogenase positive Leydig cells (LCs), associated with increased in situ cell death fluorescence and caspase-3 immuno-expression in the testes. Consequently, immunostaining for cell cycle gene regulators showed increased expressions of p45, accompanied with increased expressions of cyclin D2 and E2. Histological observations of the gonads showed reduced number of germ cells in particular areas, sloughed seminiferous epithelium, presence of giant apoptotic cells close to the seminiferous tubule lumen and in the epididymal lumen along with low numbers of Leydig cells in the testicular interstitial areas. Similarly, LCs isolated from the testes of BalB/c mice that were exposed to atrazine (0.5, 25, 50 mg kg−1 body weight) in the same manner as in the first experiment presented dose-dependent increased caspase-3 activity, decreased cell viability, intratesticular and serum testosterone concentrations and LCs testosterone secretion. In summary, atrazine appears to directly decrease the number of testosterone secreting LCs in mice through apoptosis.

Toxic effects of atrazine on immune function in BALB/c mice.

This study was aimed to evaluate the toxic effects of different concentrations (23, 90, 360mg/kg BW) of atrazine (ATZ) on immune function in BALB/c mice. Some parameters of general immunotoxicity, humoral immunity, cellular immunity, and non-specific immunity were tested. The studies showed that the high-dose ATZ induced a significant reduction in the final body weight of mice, the absolute and relative weights of spleen, the counts of white blood cell (WBC), lymphocyte (LYM), monocyte (MON), and the number of splenocyte. An increase in the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and cholesterol (CHO) in the high-dose ATZ group was observed. Pathological examination showed that the medium- and high-doses of ATZ caused atrophy and destruction of thymus, spleen, and hepatorenal toxicity. The serum interleukin-5(IL-5) level of mice and the number of plaque-forming cell (PFC) in spleen cells in the high-dose ATZ group decreased significantly while there was a significant increase of the serum immunoglobulin G (IgG) in the high-dose ATZ group when compared to the negative control group. In the high-dose ATZ group, the proliferation ability of T and B lymphocytes as well as the delayed-type hypersensitivity (DTH) response were significantly decreased. The low-dose ATZ (23mg/kg BW) caused a significant decrease in the number of WBC and neutrophil (NEUT), as well as the proportion of polychromatic and normoblast. In summary, we thought the low-dose ATZ has a slight effect on the immune system; it can be preliminarily concluded that the lowest observed adverse effect level (LOAEL) of atrazine is 23mg/kg BW in mice. Atrazine can cause immunotoxicity mainly through cellular and humoral immunity pathways.

Effect of atrazine and green fertilizer (tithonia diversifolia) on weed growth and corn productivity

The research aimed to analyze the effect of atrazine and Tithonia diversifolia green fertilizer on weed growth and corn productivity. This type of research is an experiment with randomized block design (RBD) factorial pattern with two factors. The first factor is organic material (B), which consists of 4 levels, namely: = Without organic matter (B1), Tithonia diversifolia 5 t ha-1 (B2), Tithonia diversifolia 10 t ha-1 (B3), and Tithonia diversifolia 15 t ha-1(B4). The second factor is the dose of herbicide (H) which consists of 4 levels, namely: = Without herbicide (H1), Atrazine 1 l ba ha-1 = 2.5 l ha-1 (H2), Atrazine 2 l ba ha-1 = 5 l ha-1(H3), and Atrazine 3 l ha ha-1 = 7.5 l ha-1 (H4). The study used Tithonia diversifolia weed pruning as a source of organic material. Each treatment was repeated three times so that this experiment consisted of 48 experimental units. The results of the study are weed closure ranging from 4.5 - 26% (21 DAP) and 13.42 - 40.58% (41 DAP). Symptoms of corn poisoning decreased with each addition of organic matter at each dose of atrazine. The highest dry shelled yield was obtained at a dose of 15 t ha-1. Application of Tithonia diversifolia green fertilizer dosage of 10 t ha-1 sprayed with atrazine herbicide 2 l b.a ha-1 resulted in dry shelled corn of 9.61t. The conclusion was that the atrazine herbicide and Tithonia diversifolia green fertilizer in various doses in corn plantations significantly influenced the control of weeds and corn productivity.

Carryover effect of atrazine and its metabolite-from treated bovine spermatozoa to the embryo's transcriptome†.

Atrazine (ATZ) is an extensively used herbicide and ubiquitous environmental contaminant. ATZ and its metabolite, diaminochlorotriazine (DACT), cause several cellular and functional alterations in spermatozoa. We aimed to examine the effect of ATZ/DACT on spermatozoon DNA integrity, fertilization competence, embryonic development, and transcriptome profile of in vitro-produced embryos derived from fertilization with pre-exposed sperm. Bovine spermatozoa exposed to ATZ (0.1 or 1μM) or DACT (1 or 10μM) during in vitro capacitation were used for in vitro fertilization of untreated oocytes. Cleavage and blastocyst-formation rates were evaluated 42h and 7days postfertilization, respectively. The association between DNA fragmentation and apoptosis (annexin V kit) was determined. Fertilization competence of annexin-positive (AV+) and annexin-negative (AV-) spermatozoa was examined. Microarray analysis was performed for 7-day blastocysts. Intracytoplasmic sperm injection was performed with control (AV+, AV-) and DACT (AV+, AV-) spermatozoa. Cleavage rates did not differ between groups and blastocyst formation tended to be higher for AV- vs. AV+ in both control and DACT groups, suggesting that acrosome reaction, rather than DNA fragmentation, underlies the reduced cleavage. Transcriptomic analysis revealed 139 and 230 differentially expressed genes in blastocysts derived from ATZ- and DACT-exposed spermatozoa, respectively, relative to controls. Proteomic analysis shown differential expression of proteins in ATZ- or DACT-treated spermatozoa, in particular proteins related to cellular processes and biological pathways. Therefore, we assume that factors delivered by the spermatozoa, regardless of DNA fragmentation, are also involved. Overall, the current study reveals a deleterious carryover effect of ATZ/DACT from the spermatozoa to the developing embryo.

The use of different sublethal endpoints to monitor atrazine toxicity in nematode Caenorhabditis elegans

In this work, Caenorhabditis elegans was employed as an in vivo model to determine the toxic effects of atrazine at different concentrations. After the exposure period from the larval stage L1 to adulthood day 1, atrazine (10 mg/L) significantly decreased the body length and lifespan of nematodes. In addition, exposure to ≥0.01 mg/L atrazine remarkably increased the intestinal reactive oxygen species (ROS) levels and reduced locomotion behavior of nematodes, while exposure to ≥ 1 mg/L atrazine decreased the brood size of nematodes. Moreover, atrazine (0.001–0.1 mg/L) upregulated the expression levels of hsp-6::GFP and hsp-6/60 in nematodes, indicating the activation of mitochondrial unfolded protein response (mtUPR). On the contrary, atrazine (1–10 mg/L) downregulated the expression levels of hsp-6::GFP and hsp-6/60 in nematodes. Furthermore, mtUPR induction governed by the RNAi knockdown of atfs-1 could increase the vulnerability of nematodes against atrazine toxicity. Overall, our findings highlighted the dynamic responses of nematodes toward different concentrations of atrazine, which could be monitored using different sublethal endpoints as bioindicators.

Prenatal exposure to atrazine induces cryptorchidism and hypospadias in F1 male mouse offspring.

The main objective of the present study was to determine whether prenatal exposure to atrazine could affect testicle descent and penile masculinization. Atrazine has been demonstrated with a variety of endocrine disrupting activities and reproductive toxicities. However, the effects of prenatal atrazine exposure on male offspring's genital malformation, such as hypospadias and cryptorchidism, remain poorly understood. In this study, pregnant ICR mice were gavaged from gestational day 12.5–16.5 with different doses of atrazine. Although no sign of systemic toxicity was observed in F1 male pups, prenatal exposure to 100 mg/kg/day atrazine affected penile morphology, urethral meatus position and descent of testis, and reduced anogenital distance and penile size in postnatal day 21 F1 male pups. The comparative study with an androgen receptor (AR) antagonist vinclozolin suggested that these effects of atrazine on male genital development may not be through antagonism of AR. The results also revealed that atrazine exposure significantly reduced maternal serum testosterone levels, decreased AR nuclear translocation, and altered the expression levels of developmental gene networks in developing penis of mice. Atrazine exposure also affected the expression of insulin‐like 3 (Insl3) and steroidogenic gene expression in developing reproductive tract. Therefore, our data indicate that prenatal atrazine exposure can induce hypospadias in F1 mice, likely through disruption of testosterone production, decreasing genomic androgen action, and then altering expression of developmental genes during sexual differentiation. Our data also suggest that prenatal atrazine exposure can induce cryptorchidism in F1 mice, possibly through down regulation of Insl3.

Therapeutic Effects of Ascorbic Acid on Hormonal and Histological Alteration Produced in The Reproductive System of Albino Rats Intoxicated by Herbicide Atrazine

The aim of this study was to examine the cytotoxicity of the herbicide atrazine on the reproductive system. 48 male and 48 female albino rats were treated with atrazine daily for two different durations (15 and 30 days). Reproductive system toxicity was monitored by quantitative analysis of the serum Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), Prolactin (PRL), Estrogen (E2), Progesterone (Prog) and Testosterone (Testo). On the other hand, the reproductive organs were collected for histopathology study. The study showed a significant elevation of estrogen, progesterone hormones with a significant decrease in testosterone hormone in male groups while in female groups there was a significant decrease in estrogen, progesterone & hormones with a significant increase in testosterone hormone. But there was no effect on PRL and LH hormones in both male and female groups toxified by ATZ, in comparison to the control groups. In addition to that, the Light microscopic examination of the seminiferous tubule cells (st) showed vacuolations within seminiferous tubules (V), degeneration of spermatozoa formation and hemorrhage (hg) in the interstitial tissue. These effects were increased by increasing the dose or the time of exposure. By using ascorbic acid in the treatment of those effects, we find a significant improvement and detoxification of the atrazine effects on both hormonal tests and histological sections. From our study results, we concluded that there is a potential contribution of herbicide mixtures in the etiology of somebody's diseases, while ascorbic acid has beneficial effects as it tends to dampen atrazine toxicity, in albino rats.

Adverse effects of atrazine on blood parameters, biochemical profile and genotoxicity of snow trout (Schizothorax plagiostomus).

This study was conducted to evaluate the adverse effects of atrazine on hematology, biochemistry and genotoxicity of snow trout (Schizothorax plagiostomus). Almost all treated groups presented considerably (P < 0.05) lesser values of hematocrit, hemoglobin, WBC, RBC, MCH, MCHC, monocytes and lymphocytes while significantly higher values of HCT and platelets are observed. A Significant decrease is observed in sodium, calcium, potassium, phosphorous, triglycerides, creatinine, urea, and total protein contents whereas, a significant increase is observed in cholesterol and glucose level. Significant (P < 0.05) alterations are observed in enzyme activities of all treated groups. DNA damage was observed at the concentrations (2–4 ppm). Results showed that Comet assay is reliable for evaluating the toxicity and is helpful in environmental monitoring programs.

Transcriptomic profiling of atrazine phytotoxicity and comparative study of atrazine uptake, movement, and metabolism in Potamogeton crispus and Myriophyllum spicatum

The accumulation of atrazine in sediments raises wide concern due to its potential negative effects on aquatic environments. Here we collected sediments and different submerged macrophytes to simulate natural shallow lakes and to measure atrazine levels and submerged macrophyte biomass. We determined gene expressions in submerged macrophytes treated with or without atrazine. We also examined atrazine concentrations and its metabolite structures in submerged macrophytes. When the initial concentration of atrazine in sediments ranged from 0.1 to 2.0 mg kg−1 dry weight (DW), atrazine levels in the pore water of the sediments ranged from 0.003 to 0.05 mg L−1 in 90 days. Atrazine did not show obvious long-term effects on the biomass of Potamogeton crispus and Myriophyllum spicatum (P > 0.05). On day 90, gene expressions related to cell wall in P. crispus were changed by atrazine phytotoxicity. Moreover, the decrease in the number genes controlling light-harvesting chlorophyll a/b-binding proteins verified the toxic effects of atrazine on the photosynthesis of M. spicatum. Compared with unexposed plants on day 90, ribosome pathway was significantly enriched with differentially expressed genes after submerged macrophytes were exposed to 2.0 mg kg−1 DW atrazine (P < 0.05). In addition, shoots and roots of P. crispus and M. spicatum could absorb the equal amount of atrazine (P > 0.05). Once absorbed by submerged macrophytes, atrazine was degraded into 1-hydroxyisopropylatrazine, hydroxyatrazine, deethylatrazine, didealkylatrazine, cyanuric acid, and biuret, and some of its metabolites could conjugate with organic acids, cysteinyl β-alanine, and glucose. This study establishes a foundation for aquatic ecological risk assessments and the phytoremediation of atrazine in sediments.

Glyphosate and atrazine inhibit growth of Azospirillum brasilense, Bacillus subtilis, Bacillus thuringiensis, Chromobacterium subtsugae and Saccharopolyspora spinosa

Glyphosate and atrazine are two herbicides used worldwide to ensure high yields in different types of crops. Despite the importance of herbicides, their application may have negative effects on non-target organisms, including bacteria used in biological control and biological nitrogen fixation. Therefore, this research aimed to analyze the in vitro effect of glyphosate and atrazine on the growth of bacteria Azospirillum brasilense, Bacillus subtilis, Bacillus thuringiensis, Chromobacterium subtsugae, and Saccharopolyspora spinosa. The design used was completely randomized, and the doses of the herbicides evaluated were 1.0, 2.0, 3.0 and 4.0 L ha-1. The results showed that glyphosate and atrazine affected the development of the bacteria under study. Atrazine showed a lineal increasing effect between the doses used and inhibition of bacterial growth. Therefore, the dose of 4.0 L ha-1 of this herbicide was the one that showed the highest inhibition of bacteria, whereas glyphosate at a dose of 2.0 L ha-1 showed the highest inhibition of bacteria compared to doses of 1.0, 3.0 and 4.0 L ha-1.

Hepatotoxic Effects of Atrazine on Clarias gariepinus (Burchell, 1822): Biochemical and Histopathological Studies

The hepatotoxic effects of sub-lethal concentrations of atrazine (2.5, 25, 250, and 500μg L-1) on Clarias gariepinus juveniles were assessed for 28days in a quality-controlled laboratory procedure. The study was designed to determine the effects of atrazine on selected liver function biomarkers: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), albumin (ALB) and total protein (TP), and to analyze the liver tissues of the fish using a quantitative and qualitative histology-based health assessment protocol. The levels of ALB and TP in exposed specimens were observed to decrease with increasing concentrations of atrazine. However, the activities of ALT, AST, and ALP showed significant (p < 0.05) increase with increasing concentrations of atrazine. Hepatic assessment of the liver tissues revealed marked histopathological alterations, including structural changes (necrotic/apoptotic liver tissue, poor hepatic cord structure, and loss of normal architecture) in 52.2% of the liver tissues in the treatment groups; plasma alterations (vacuolation or fat inclusions, 22.9%) of hepatocytes; hypertrophied hepatocyte (55.2%); nuclear alterations (52.1%); focal necrosis (16.7%); complete degeneration of hepatocytes (60.45%); sinusoids congested with red blood cells or vascular congestion (70.8%); and karyolysis of the nucleus (18.8%). Findings from this study suggest that atrazine interferes with liver function markers and disrupts the normal architectural and structural components of the liver resulting in noninfectious liver injury. This condition resulted in repeated cycles, cell deaths, and inflammation, which could result in the eventual death of the exposed fish if exposure duration was prolonged.