Toxicity,monitoring and biodegradation of the fungicide carbendazim

The increasing use of toxic pesticides is a major environmental concern. Carbendazim is a systemic fungicide having wide applications for controlling fungal diseases in agriculture, forestry and veterinary medicines. Carbendazim is a major pollutant detectable in food, soil and water. Carbendazim extensive and repeated use induces acute and delayed toxic effects on humans, invertebrates, aquatic life forms and soil microorganisms. Here, we review the pollution, non-target toxicity and microbial degradation of carbendazim for crop and veterinary purposes. We found that carbendazim causes embryotoxicity, apoptosis, teratogenicity, infertility, hepatocellular dysfunction, endocrine-disrupting effects, disruption of haematological functions, mitotic spindle abnormalities, mutagenic and aneugenic effect. We also found that carbendazim disrupted the microbial community structure in various ecosystems. The detection of carbendazim in soil and reservoir sites is performed by spectroscopic, chromatographic, voltammetric, nanoparticles, carbon electrodes and mass spectrometry. A review of the degradation of carbendazim shows that carbendazim undergoes partial to complete biodegradation in the soil and water by Azospirillum, Aeromonas, Alternaria, Bacillus, Brevibacillus, Nocardioides, Pseudomonas, Ralstonia, Rhodococcus, Sphingomonas, Streptomyces and Trichoderma.     

Worldwide contamination of water by fluoride

Fluoride contamination in water is a major problem across the globe, with health hazards such as dental and skeletal fluorosis. Most earlier studies are confined to local or regional scales. As the problem has serious socioeconomic implications, there is a need for a global perspective. Thus, here we review worldwide research for nearly a century on fluoride contamination in water. We investigated the distribution of fluoride contamination in water, its sources, mobilization and association. The major findings are: (1) Anomalous fluoride concentration in groundwater is mainly confined to arid and semiarid regions of Asia and North Africa. (2) The geogenic sources of fluoride in water are mainly fluorine-bearing minerals in rocks and sediments, whereas anthropogenic sources of fluoride in water are mainly pesticides and industrial waste. (3) Fluoride mobilization from geogenic sources is mainly controlled by alkalinity and temperature. (4) Fluoride occurrence in water is associated with ions such as sodium, arsenic chloride and bicarbonate. There are few associations of fluoride in water with calcium and magnesium.     

Assessment of petroleum hydrocarbon in a tropical brackish water lagoon: Chilika,India

Assessment of petroleum hydrocarbon (PHC) in the Chilika Lagoon, India, revealed a significant spatio-temporal variation in surface water (analysis of variance: n?=?120, p?相似文献   

A numerical study of hypothetical storm surge and coastal inundation for AILA cyclone in the Bay of Bengal

The head Bay region bordering the Bay of Bengal is highly vulnerable to tropical cyclones. Catastrophic risks from storm surge and associated inundation are quite high due to high population density in coastal areas, socio-economic conditions, and shallow bathymetry. It features the world’s largest deltaic system comprising of ‘Sunderbans’ bordered by West Bengal and Bangladesh. In a geomorphologic sense, the head Bay region is a low-lying belt comprising several barrier islands and river drainage systems, numerous tidal creeks, and mud flats having a high risk for widespread inundation. In addition, the high tidal range together with low-lying topography leads to high risk and vulnerability from storm surge inundation. During May 2009, a severe cyclonic storm Aila struck West Bengal causing enormous destruction to life and property along coastal belts of West Bengal and Bangladesh. It was the strongest pre-monsoon cyclone in the past two decades that had landfall in West Bengal. This work reports on a numerical study for hypothetical storm surge and associated inundation from Aila using the ADCIRC model. The study covers a comprehensive qualitative analysis on water level elevation and onshore inundation for West Bengal and Bangladesh regions. The estimated peak storm surge was about 4 m in the Sunderban region that propagated into all major riverine systems, inundating the river banks as well the inland areas. Numerical simulations indicate an average inland penetration distance of 350 m with a maximum of 600 m at various coastal locations in West Bengal and Bangladesh. The study emphasizes the need and importance of inundation modeling system required for emergency preparedness and disaster management.     

Rice seedlings under cadmium stress: effect of silicon on growth,cadmium uptake,oxidative stress,antioxidant capacity and root and leaf structures

In this study, the effect of silicon (Si) addition on cadmium (Cd) toxicity in rice seedlings was investigated. After a series of screening experiments, 50 μmol·L^?1 of Cd and 10 μ mol·L^?1 of Si were selected. Treatment of rice seedlings with Cd (50 μ mol·L^?1) resulted in significant accumulation of this metal in roots and shoots. The data revealed that accumulation of Cd resulted in oxidative stress in rice seedlings as evidenced by increased accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA; a peroxidation product of lipids). However, addition of Si (10 μ mol·L^?1) together with Cd prevented accumulation of Cd, H₂O₂ and MDA. Antioxidant capacity was decreased by Cd but enhanced by Si addition. Cd decreased the length and frequency of root hairs, stomatal frequency, and distorted leaf mesophyll cells and vascular bundles. However, addition of Si together with Cd reduced these abnormalities. The results showed that addition of exogenous Si protected rice seedlings against Cd toxicity by preventing Cd accumulation and oxidative stress (H₂O₂ and MDA accumulation) by increasing Si accumulation and antioxidant capacity, which maintained the structure and integrity of leaf and root.     

Nerve conduction studies in sprayers occupationally exposed to mixture of pesticides in a mango plantation at Lucknow,North India

In this study, nerve conduction, organochlorine (OC) pesticide residues in blood and cholinesterase activity levels of pesticide sprayers employed in mango plantations at Lucknow, North India, were determined. Fifty-two sprayers from mango plantations who regularly spray mixture of pesticides like organophosphates (OP), OCs, and carbamates were considered as exposed group. Eighteen subjects with similar socio-economic status of exposed group, who do not handle pesticides, were selected as controls. Questionnaire-based interviews related to personal and occupational histories of the study subjects were carried out. Sprayers did not use any personal protective equipment during pesticide handling. The blood-pesticide analyses of sprayers show higher mean values of hexachlorohexane (HCH), γ-HCH, δ-HCH, total HCH, op-DDT compared with the controls. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activites were significantly reduced among sprayers. Risk of motor nerve conduction deficits was observed in sprayers with low AChE activity. Negative correlation of motor and sensory nerve conduction deficits was observed with the duration of exposure and age among sprayers. The study demonstrated that the prolonged exposure to mixture of pesticides, ergonomic factors, decline in cholinesterase activity may lead to nerve conduction dysfunction. The findings suggest the need for controlled use of pesticides in the plantation and indicated the need for training and implementation of hygiene practices like proper usage of personal protective equipments.     

Sodium cyanide-induced modulations in the activities of some oxidative enzymes and metabolites in the fingerlings of Cyprinus carpio (Linnaeus)

Carp fingerlings exposed to a sublethal concentration (0.5?mg?L^?1) of sodium cyanide showed a steady decrement over a 7-day period in respiratory rate, rise in lactate dehydrogenase (LDH), and fall in succinate dehydrogenase (SDH) activities followed by variations in lactic and pyruvate levels. Changes in these enzyme activities might be due to impaired oxidative metabolism and severe cellular damage leading to the release of these enzymes. Decline in the activities of SDH and LDH clearly represents a shift from aerobic to anaerobic metabolism as evidenced by elevated lactate and decline in pyruvate levels. The shift to anaerobic metabolism is also reflected by severe drop in the respiratory rate of the fish. This may be a consequence of the blockage of electron transfer from cytochrome c oxidase to molecular oxygen, thus ceasing cellular respiration and it can lead to cellular hypoxia even in the presence of normal hemoglobin oxygenation. Hence, we indirectly reconfirm the inhibition of oxidative metabolism by sodium cyanide. Alterations in behavioral pattern induced by sublethal sodium cyanide exposure may be due to the combination of cytotoxic hypoxia with lactate acidosis, which depresses the central nervous system (CNS); as the brain is the most sensitive site to anoxia, it results in impaired CNS function.     

Antidiabetic effects of Trigonella foenum-graecum seed powder in a rat model

Free radical production and oxidative stress are known to increase in liver during diabetes and may contribute to oxidative damage. In this study, the effect of oral feeding of Trigonella foenum-graecum seed powder (TSP) has been studied on blood glucose, membrane-linked ATPases, antioxidant enzymes, lipid peroxidation, lipofuscin content and membrane fluidity in livers of a diabetic rat. Diabetes was induced by administration of alloxan monohydrate. Hyperglycemia during diabetes has been shown to entail free radical generation, with a concomitant increase in lipid peroxidation and lipofuscin content, inhibition of membrane-linked ATPases, increased antioxidant enzyme activities and decreased membrane fluidity. TSP treatment reverses the changes to near normal levels thereby ameliorating the management of diabetic complications.     

Differential effects of UV-B radiation fluence rates on growth,photosynthesis, and phosphate metabolism in two cyanobacteria under copper toxicity

This work was undertaken to ascertain the impact of different fluence rates of ultraviolet-B (UV-B) radiation on two cyanobacterial biofertilizers, Phormidium foveolarum and Nostoc muscorum, growing under copper toxicity. Copper (2 and 5?µmol?L^?1) and high UV-B fluence rate (UV-B_H; 1.0?µmol?m^?2?s^?1) decreased the growth, pigment content, photosynthetic oxygen yield, phosphate uptake, and acid phosphatase activity in both the strains analyzed after 24 and 72?h of experiments, and combined exposure further enhanced the toxic effects. Respiration and alkaline phosphatase activities were stimulated appreciably. The damaging effect was shown on the order on pigments: phycocyanin?>?chlorophyll a?>?carotenoids, and on photosystems: whole chain photosynthetic reaction?>?photosystem II?>?photosystem I. Partial recovery in the photosystem II activity in the presence of artificial electron donors; diphenyl carbazide (DPC), hydroxylamine (NH₂OH), and manganese chloride (MnCl₂) pointed out the interruption of electron flow on the oxidation side of photosystem II. Unlike UV-B_H, low UV-B fluence rate (UV-B_L; 0.1?µmol?m^?2?s^?1), rather than causing damaging effect partially, alleviated the toxic effects of Cu. This study suggests that the cyanobacterium P. foveolarum is less sensitive against UV-B_H and excess Cu (2 and 5?µmol?L^?1), thus P. foveolarum may be used as a biofertilizer for sustainable agriculture.     

Design,synthesis, antinociceptive,and anti-inflammatory properties of thiazolopyrimidine derivatives

Ten 2-(substituted benzylidene)-7-(4-chlorophenyl)-5-(furan-2-yl)-2H-thiazolo[3,2-a]pyrimidin-3(7H)-one derivatives were synthesized and evaluated. A series of heterocyclic, 2-(substituted benzylidene)-7-(4-chlorophenyl)-5-(furan-2-yl)-2H-thiazolo[3,2-a]pyrimidin-3(7H)-one were synthesized by reaction of 7-(4-chloro phenyl)-5-(furan-2-yl)-2H-thiazolo[3,2-a]pyrimidin-3(7H)-one with appropriately substituted aldehydes in the presence of anhydrous sodium acetate and glacial acetic acid. The antinociceptive activity was evaluated by tail-flick technique, anti-inflammatory activity was evaluated by carrageenan-induced paw edema test and their ulcerogenicity index was determined. The para-substituted methyl, hydroxy, fluoro, chloro, bromo, and nitro derivatives showed significant antinociceptive and anti-inflammatory activities. The detailed synthesis, spectroscopic data, and pharmacological screening of the synthesized compounds were reported.