Arsenic and dichlorvos: Possible interaction between two environmental contaminants

Tiger nut/coconut dietary intervention as antidotal nutritional remediation strategy against neurobehavioural deficits following organophosphate-induced gut-brain axis dysregulation in mice

Organophosphate poisoning remains a global health crisis without efficacious treatments to prevent neurotoxicity. We examined whether antidotal tiger nut and coconut dietary intervention could ameliorate neurobehavioral deficits from organophosphate dichlorvos-induced gut-brain axis dysregulation in a mouse model. Mice were divided into groups given control diet, dichlorvos-contaminated diets, or dichlorvos plus nut-enriched diets. They were exposed to a DDVP-contaminated diet for 4 weeks before exposure to the treatment diets for another 8 weeks. This was followed by behavioural assessments for cognitive, motor, anxiety-, and depressive-like behaviours. Faecal samples (pre- and post-treatment), as well as blood, brain, and gut tissues, were collected for biochemical assessments following euthanasia. Dichlorvos-exposed mice displayed impairments in cognition, motor function, and mood along with disrupted inflammatory and antioxidant responses, neurotrophic factor levels, and acetylcholinesterase activity in brain and intestinal tissues. Weight loss and altered short-chain fatty acid levels additionally indicated gut dysfunction. However, intervention with tiger nut and/or coconut- enriched diet after dichlorvos exposure attenuated these neurobehavioral, and biochemical alterations. Our findings demonstrate organophosphate-induced communication disruptions between the gut and brain pathways that manifest in neuropsychiatric disturbances. Overall, incorporating fibre-rich nuts may represent an antidotal dietary strategy to reduce neurotoxicity and prevent brain disorders associated with organophosphate poisoning.

Protective Effect of Quercetin and Ginger (Zingiber officinale) Extract against Dimethoate Potentiated Fluoride-Induced Nephrotoxicity in Rats

This study aimed to determine the potential of quercetin and Zingiber officinale (ZO) Roscoe extract to alleviate the renal damage induced by dimethoate (DM) and fluoride (F^-) alone and by their combined exposure in rats. A total of 54 adult Wistar rats were randomly allocated to nine groups (n = 6). A sub-lethal dose of DM (1/10th of the median lethal dose) was administered by oral gavage alone and along with F^- (4.5 ppm, three-fold the permissible limit) in their drinking water continuously for 28 days. Chromatographical analysis revealed the presence of quercetin, curcumin, and other phytochemicals with strong antioxidant properties in ZO-rhizome extract. Severe changes were observed in the levels of the renal biomarkers and histoarchitecture after co-administration of the toxicants, indicating greater kidney damage. The administration of ZO extract (300 mg/kg) along with either or both toxicants led to a significant restoration of the biochemical markers and renal antioxidant profile and histology.

Correlation of bacterial community with phosphorus fraction drives discovery of Actinobacteria involved soil phosphorus transformation during the trichlorfon degradation

Trichlorfon (TCF) is a broad-spectrum phosphorus (P)-containing pesticide, yet its effects on soil P fraction transformation and bacterial communities during the TCF degradation in soils is unknown. In this study, we investigated soil TCF degradation behavior at different contents of 50, 100 and 200 mg/kg, and analyzed residual TCF contents and metabolites by gas chromatography mass spectrometry after 216-h incubation. Our results suggested that TCF was gradually degraded in soils and was be initially hydrolyzed to dichlorvos via P-C bond cleavage and then other P-containing metabolites. By analyzing different P fractions and soil microbial community composition, we found significant increases of soil available phosphorus contents from 2.76 mg/kg (control) to 3.23 mg/kg (TCF-50), 5.12 mg/kg (TCF-100) and 5.72 mg/kg (TCF-200), respectively. Inorganic CaCl₂-P was easily and instantly transformed to primary mineral inorganic P (P_i) forms of HCl-P and citrate-P, while the proportion of enzyme-P (a labile organic P) fluctuated throughout TCF degradation process. Soil available P contents and P_i fractions were significantly correlated with the relative abundance of Actinobacteria. These results highlighted that Actinobacteria is the dominant soil species utilizing TCF as P sources to increase its community richness, and subsequently affect the transformation of P fractions to regulate soil P cycle. Our study gives new understanding on the microorganisms can involve soil P transformation during organophosphorus pesticides degradation in soils, highlighting the importance of bacteria in P transformation and pesticides soil decontamination.

Molecular Interactions Associated with Coagulation of Organic Pollutants by 2S Albumin of Plant Proteins: A Computational Approach

The removal of organic pollutants is a major challenge in wastewater treatment technologies. Coagulation by plant proteins is a promising technique for this purpose. The use of these proteins has been experimentally investigated and reported in the literature. However, the determination of the molecular interactions of these species is experimentally challenging and the computational approach offers a suitable alternative in gathering useful information for this system. The present study used a molecular dynamic simulation approach to predict the potentials of using Moringa oleifera (MO), Arachis hypogaea, Bertholletia excelsa, Brassica napus, and Helianthus annuus plant proteins for the coagulation of organic pollutants and the possible mechanisms of coagulation of these proteins. The results showed that the physicochemical and structural properties of the proteins are linked to their performance. Maximum coagulation of organic molecules to the proteins is between 50–100%. Among five proteins studied for coagulation, Brassica napus and Helianthus annuus performed better than the well-known MO protein. The amino acid residues interacting with the organic molecules play a significant role in the coagulation and this is peculiar with each plant protein. Hydrogen bond and π—interactions dominate throughout the protein–pollutants molecular interactions. The reusability of the proteins after coagulation derived from their structural quality analysis along with the complexes looks promising and most of them are better than that of the MO. The results showed that the seed proteins studied have good prediction potentials to be used for the coagulation of organic pollutants from the environment, as well as the insights into their molecular activities for bioremediation.

Advances in organophosphorus pesticides pollution: Current status and challenges in ecotoxicological, sustainable agriculture, and degradation strategies

Organophosphorus pesticides (OPPs) are one of the most widely used types of pesticide that play an important role in the production process due to their effects on preventing pathogen infection and increasing yield. However, in the early development and application of OPPs, their toxicological effects and the issue of environmental pollution were not considered. With the long-term overuse of OPPs, their hazards to the ecological environment (including soil and water) and animal health have attracted increasing attention. Therefore, this review first clarified the classification, characteristics, applications of various OPPs, and the government's restriction requirements on various OPPs. Second, the toxicological effects and metabolic mechanisms of OPPs and their metabolites were introduced in organisms. Finally, the existing methods of degrading OPPs were summarized, and the challenges and further addressing strategy of OPPs in the sustainable development of agriculture, the environment, and ecology were prospected. However, methods to solve the environmental and ecological problems caused by OPPs from the three aspects of use source, use process, and degradation methods were proposed, which provided a theoretical basis for addressing the stability of the ecological environment and improving the structure of the pesticide industry in the future.

Elemental plasma content and urinary excretion in vineyard farmers occupationally exposed to pesticides in southern Brazil

This is a cross-sectional study with data and biological material collection from vineyard farmers in southern Brazil. An interview was carried out through a questionnaire developed according to the reference guide of the state government. Plasma and urine samples were screened for Aluminum, Chromium, Manganese, Copper, Nickel, Cobalt, Zinc, Arsenic, Selenium, Cadmium, Antimony, Barium, Mercury, Lead and Uranium, with a technique for fast determination of these elemental contents in biological material utilizing dynamic reaction cell inductively coupled mass spectrometry. Principal component analysis was used to identify associations between these elemental contents in biological samples and the information obtained from the interviews. The farmers showed some trace elements in plasma and urine at a higher concentration than unexposed populations from other studies. This study highlights recent findings of trace elements in biological material and their association with characteristics of pesticide use. In addition, it also contributes to the gap in the literature regarding trace elements content in plasma and urine of workers exposed to pesticides.

Arsenic-induced uterine apoptotic damage is protected by ethyl acetate fraction of Camellia sinensis (green tea) via Bcl-2-BAX through NF-κB regulations in Wistar rats

The non-invasive treatment strategy is indispensable to overcome the side effects of conventional treatment with chelating agents against arsenic. Presence of catechins and flavonoids in Camellia sinensis have potential antioxidant properties and other beneficial effects. The aim of the study was to explore the curative potential role of Camellia sinensis against uterine damages produced by sodium arsenite in mature albino rats. A dose of 10 mg of Camellia sinensis ethyl acetate (CS-EA) fraction/100 gm body weight was provided to the sodium arsenite-treated rats (10 mg/Kg body weight). LC-MS analysis was used for the detection of active component in CS-EA fraction. Enzymatic antioxidants analysis carried out by reproducible native gel technique. Hormones and some pro and anti-inflammatory markers were detected by ELISA, PCR, and western blot techniques respectively. Immunostaining was performed for the detection of estradiol receptor alpha. LC-MS analysis of CS-EA fraction ensured the presence of active tea polyphenol and tea catechin of which highest peak of epigallocatechin-3 gallate (EGCG) was obtained in this study. Significant elevations of lipid peroxidation end products followed by the diminution of antioxidant enzymes activities were noted in arsenicated rats which were capably retrieved by the treatment of CS-EA fraction. Post-treatment with CS-EA fraction meaningfully improved gonadotrophins and estradiol signalling in association with a highly expressing estradiol receptor-α (ERα) in the ovary and uterus followed by the maintenance of normal utero-ovarian histoarchitecture in arsenic fed rats. CS-EA fractioned treated group overturned the sodium arsenite driven higher expression of pro-inflammatory cytokines and proapoptotic markers along with a low level of anti apoptotic Bcl-2 expression and comparatively lower NF-κB signalling in the uterus via regulating IKK β kinase mostly by EGCG of CS-EA fraction. However, ethyl acetate fraction of Camellia sinensis played a critical role in minimizing arsenic-mediated uterine hypo-function.

Emerging Technologies for Degradation of Dichlorvos: A Review

Dichlorvos (O,O-dimethyl O-(2,2-dichlorovinyl)phosphate, DDVP) is a widely acknowledged broad-spectrum organophosphorus insecticide and acaracide. This pesticide has been used for more than four decades and is still in strong demand in many developing countries. Extensive application of DDVP in agriculture has caused severe hazardous impacts on living systems. The International Agency for Research on Cancer of the World Health Organization considered DDVP among the list of 2B carcinogens, which means a certain extent of cancer risk. Hence, removing DDVP from the environment has attracted worldwide attention. Many studies have tested the removal of DDVP using different kinds of physicochemical methods including gas phase surface discharge plasma, physical adsorption, hydrodynamic cavitation, and nanoparticles. Compared to physicochemical methods, microbial degradation is regarded as an environmentally friendly approach to solve several environmental issues caused by pesticides. Till now, several DDVP-degrading microbes have been isolated and reported, including but not limited to Cunninghamella, Fusarium, Talaromyces, Aspergillus, Penicillium, Ochrobium, Pseudomonas, Bacillus, and Trichoderma. Moreover, the possible degradation pathways of DDVP and the transformation of several metabolites have been fully explored. In addition, there are a few studies on DDVP-degrading enzymes and the corresponding genes in microorganisms. However, further research relevant to molecular biology and genetics are still needed to explore the bioremediation of DDVP. This review summarizes the latest development in DDVP degradation and provides reasonable and scientific advice for pesticide removal in contaminated environments.

Simulation of hemo- and biochemical toxicities associated with chronic inhalation exposure to 2,2-Dichlorovinyl dimethyl phosphate (DDVP) in Wistar rat

DDVP is a commonly used pesticide in Nigeria and those involved with DDVP manufacturing, packaging or utilizing facilities seldom use PPE to limit pesticide exposure. The study aim was to determine the impact of chronic exposure to DDVP by monitoring hematological and biochemical changes in Wistar rats. Male rats (n = 60; 150-180 g) were exposed to graded DDVP concentrations (0%, 20 %, 40 %, 60 %, 80 % and 100 %) via inhalation route for 60 days. Body weights were initially measured and then at 20-day intervals. Blood samples were collected for hematology and serum biochemistry on day 61. Results showed significant (p < 0.05) polycythemia, neutrophilia, thrombocytosis, hepatic and renal derangement in rats exposed to DDVP. Also, albumin, AST, ALP, creatinine, blood urea nitrogen, bilirubin levels and dyslipidemia significantly increased. Cholinergic signs and stunted growth were observed in higher concentrations. Study emphasized hazards of DDVP mishandling and risks of non-compliance with PPE use by workers in-contact with DDVP, as well as misuse/abuse in animals.

Association of co-accumulation of arsenic and organophosphate insecticides with diabetes and atherosclerosis in a rural agricultural community: KMCH-NNCD-I study

AIMS

In last few decades, the prevalence of diabetes and vascular diseases has intensified concurrently with increased use of synthetic chemicals in agriculture. This study is aimed to evaluate the association of co-accumulation of arsenic and organophosphate (OP) insecticides with diabetes and atherosclerosis prevalence in a rural Indian population.

METHODS

This study included observations from KMCH-NNCD-I (2015) cross-sectional study (n = 865) from an Indian farming village. The participants had assessment of clinical parameters including HbA_1c and carotid intima-media thickness and urinary heavy metals. Serum OP residues were extracted and quantified by GC-MS. Statistical analyses were performed to unravel the co-association of arsenic and OPs on prevalence of diabetes and atherosclerosis.

RESULTS

On multivariate regression analyses, total organophosphate level and arsenic accumulation showed association with diabetes and atherosclerosis. Higher odds ratio with significant trends were observed for the sub-quartiles formed by the combination of higher quartiles of arsenic and total organophosphates in association with diabetes and atherosclerosis.

CONCLUSIONS

We observed evidence of possible synergism between arsenic and OPs in association with prevalence of diabetes, pre-diabetes and atherosclerosis in the study population. Our findings highlight the importance of understanding health effects of mixed exposures and raises vital questions on the role of these agrochemicals in the etiology of diabetes and vascular diseases.

Association of arsenic-related AS3MT gene and antioxidant SOD2 gene expression in industrial workers occupationally exposed to arsenic

Increasing anthropogenic activities related to industrialization and exposure to different toxicants increases the health hazards of industrial workers. Arsenic (As) exposure induces DNA damage and generates reactive oxygen species, which may result in many disease phenotypes. Present study explores the expression variation of As 3 methyltransferase ( AS3MT) and superoxide dismutase ( SOD2) genes in blood samples of industrial workers of different industries (brick kiln, paint, welding, pesticide, and furniture) using quantitative real-time polymerase chain reaction. A total of 250 blood samples of industrial workers were collected along with age- and gender-matched controls. Relative expression of AS3MT ( p < 0.05) and SOD2 ( p < 0.01) genes was found significantly downregulated in exposed workers compared to controls. Significant low levels of AS3MT and SOD2 gene expression were observed in workers in the paint and pesticide industry compared to other industries. Similarly, reduced expression of AS3MT ( p < 0.05) and SOD2 ( p < 0.01) was observed in smokers of industrial workers compared to smokers of the control group. Workers with >10 years of exposure had less AS3MT expression compared to workers with <10 years of exposure. Additionally, a positive Spearman correlation was observed between AS3MT versus SOD2 ( r = 0.742; p < 0.0001) in industrial workers. This study suggests that decreased AS3MT and SOD2 expression levels may lead to bioaccumulation of As in the body accompanied by increased oxidative stress ultimately inducing DNA damage.

Exposure to environment chemicals and its possible role in endocrine disruption of children from a rural area

Endocrine disrupting chemicals (EDCs), including pesticides and metals, are present in rural areas, endangering the health of exposed populations. This work aimed to investigate the possible association between the exposure to these xenobiotics and thyroid dysfunction in children living in a rural community of Southern Brazil. Fifty-four children aged 5-16 years participated in this study. Peripheral biomarker evaluations were performed in periods of low and high exposure to pesticides. Thyroid ultrasonography was evaluated in the high exposure period. Blood levels of chromium (Cr), manganese (Mn), mercury (Hg), and lead (Pb), as well as hair Pb levels were positively correlated with thyroid stimulating hormone (TSH) concentrations and negatively associated with free thyroxine (fT4) levels in the low exposure period. Prolactin was positively associated with hair Mn in both periods. In the ultrasound tests, the majority of children presented a normal echogenicity of thyroid. Glucose was inversely associated with the biomarker of exposure to cholinesterase inhibitor insecticides, butyrylcholinesterase (BuChE). Lipid profile was above the recommended levels in both periods. In summary, our results show that children environmentally exposed to a mixture of xenobiotics in an agricultural community may have health impairments, especially on thyroid function, dyslipidemia, and glucose homeostasis disruption.

Spatio-Temporal Analysis of Natural and Anthropogenic Arsenic Sources in Groundwater Flow Systems

The presence of arsenic in groundwater constitutes a hazard for the environment and human health, and the determination of its source has become a global challenge, which can be approached by defining the natural background levels (NBL) in conjunction with the indicator kriging method, with the aim of delineating anthropogenically contaminated areas. However, having a unique value of NBL for large areas can generate interpretation errors. This research integrates the determination of the flow systems present in the Calera Aquifer, and the definition of the natural background levels in each flow system by making estimation maps in ArcGIS using two databases, 10 years apart, to evaluate the spatio-temporal variation of arsenic in groundwater. The results indicate a notable increase in the probability of exceeding the arsenic NBL, mainly in the intermediate flow, which may be due to movement resulting from mining activities as well as a mixture of regional and intermediate flows caused by the extraction of water for agriculture and drinking water supplies. The presented values exceed the maximum limits allowed for human consumption, as stated by the World Health Organization.

The consequence of NAC on sodium arsenite-induced uterine oxidative stress

Arsenic consumption through drinking water is a worldwide major health problem. Management of arsenic intoxication with invasive, painful therapy using metal chelators is usually used as a conventional treatment strategy in human. In this present study, we examined the efficacy of oral administration of N-acetyl l-cysteine (NAC) in limiting arsenic-mediated female reproductive disorders and oxidative stress in female Wistar rats. The treatment was continued for 8 days (2 estrus cycles) on rats with sodium arsenite (10 mg/Kg body weight) orally. We examined the electrozymographic imprint of three different enzymatic antioxidants in uterine tissue. Rats fed with sodium arsenite exhibited a significant lessening in the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx). Uterine DNA breakage, necrosis, ovarian and uterine tissue damage, disruption in steroidogenesis were also found in arsenic treated rats. Co-administration of NAC at different doses (50 mg/kg body weight, 100 mg/kg body weight, respectively) significantly reversed the action of uterine oxidative stress markers like malondialdehyde (MDA), conjugated dienes (CD) and non protein soluble thiol (NPSH); and noticeably improved antioxidant status of the arsenic fed rats. This ultimately resulted in the uterine tissue repairing followed by improvement of ovarian steroidogenesis. However, this effective function of NAC might be crucial for the restoration of arsenic-induced female reproductive organ damage in rats.

The brains of bats foraging at wastewater treatment works accumulate arsenic, and have low non-enzymatic antioxidant capacities

Increasing rates of urbanisation cause ubiquitous infrastructures that remove anthropogenic contaminants - particularly Wastewater Treatment Works (WWTWs) - to become stressed, and hence pollute surrounding water systems. Neoromicia nana bats are suitable models to study the effects of pollution in these environments because they exploit abundant pollutant-tolerant chironomid midges that breed at WWTWs, and consequently accumulate metals such as iron, copper and zinc in their livers and kidneys. If these metals persist in their circulatory systems, and cross the blood brain barrier (BBB) they can have adverse effects on critical functions such as flight and echolocation. The aim of this study was to investigate the potential neurological effects on N. nana foraging at WWTWs versus bats at reference sites in Durban, South Africa. Our objectives were to 1) compare trace metal levels in brain and hair samples (as a proxy for circulating metals) between N. nana foraging at WWTWs and reference sites to determine if excess metals pass through the BBB via the circulatory system; and 2) compare biomarkers of neuron function (acetylcholinesterase activity), protection (antioxidant capacity), DNA integrity (DNA fragmentation), lipid integrity (lipid peroxidation) and cell viability (caspase-3 activity) between N. nana foraging at WWTW and reference sites. We found a significantly higher concentration of arsenic in hair (p < 0.05) and brain tissue (p < 0.1) of WWTW bats compared to bats at reference sites. By contrast, acetylcholinesterase activity did not differ in bats among sites and there was no evidence of significant differences in lipid peroxidation, compromised DNA integrity or apoptosis in the brains between WWTW bats and reference site bats. However, total antioxidant capacity was significantly lower in brains of WWTW bats than bats at reference sites suggesting that antioxidant protection may be compromised. Long-term exposure to environmental pollutants at WWTWs may therefore affect cellular processes and protection mechanisms in brains of N. nana bats. It may also affect other mechanisms and functions in the brain such as mitochondrial efficiency and other neurotransmitters but that remains to be tested.

Arsenite induces DNA damage via mitochondrial ROS and induction of mitochondrial permeability transition

Arsenite is an established DNA-damaging agent and human carcinogen. We initially selected conditions in which the metalloid causes DNA strand scission in the absence of detectable apoptotic DNA degradation in U937 cells. This response was suppressed by catalase and by treatments (rotenone and ascorbic acid), or manipulations (respiration-deficient phenotype), preventing the mitochondrial formation of O2-. ( mitoO2-.). MitoO2-., and its dismutation product, H₂ O₂ , are therefore critically involved in the arsenite-dependent DNA-damaging response. We then established a link between mitoO2-./H₂ O₂ and mitochondrial permeability transition (MPT), and found that this second event also promoted the formation of DNA-damaging species. As a consequence, the DNA damage induced by arsenite, in addition to being abolished by the aforementioned treatments/manipulations, was also significantly reduced by the MPT inhibitor cyclosporin A (CsA). A CsA-sensitive induction of p53 mRNA expression was also detected. Finally, evidence of CsA-sensitive DNA strand scission was also obtained in MCF-7, HT22, and NCTC-2544 cells. MitoO2-./H₂ O₂ therefore directly mediates DNA damage induced by arsenite and indirectly promotes the formation of additional DNA-damaging species via the induction of MPT. © 2017 BioFactors, 43(5):673-684, 2017.

N-acetylcysteine and meso-2,3-dimercaptosuccinic acid alleviate oxidative stress and hepatic dysfunction induced by sodium arsenite in male rats

Environmental exposure to arsenic represents a serious challenge to humans and other animals. The aim of the present study was to test the protective effect of antioxidant N-acetylcysteine (NAC) either individually or in combination with a chelating agent, meso-2,3-dimercaptosuccinic acid (DMSA), against sodium arsenite oral toxicity in male rats. Five groups were used: control; arsenic group (orally administrated in a concentration of 2 mg/kg body weight [b.w.]); the other three groups were orally administrated sodium arsenite in a concentration of 2 mg/kg b.w. followed by either NAC (10 mg/kg b.w., intraperitoneally [i.p.]), DMSA (50 mg/kg b.w., i.p.) or NAC plus DMSA. Arsenic toxicity caused significant rise in serum aspartate aminotransferase, alanine aminotransferase and total bilirubin, and a significant decrease in total protein (TP) and albumin levels after 3 weeks of experimental period. In addition, arsenic-treated rats showed significantly higher arsenic content in liver and significant rise in hepatic malondialdehyde level. By contrast, sharp decreases in glutathione content and catalase and glutathione reductase activities were discernible. NAC and/or DMSA counteracted most of these physiologic and biochemical defects. NAC monotherapy was more effective than DMSA in increasing TP, while DMSA was more effective in decreasing alanine aminotransferase. The combined treatment was superior over monotherapies in recovery of TP and glutathione. Biochemical data were well supported by histopathological and ultrastructural findings. In conclusion, the combination therapy of NAC and DMSA may be an ideal choice against oxidative insult induced by arsenic poisoning.