Inhibitory effects of paraquat on photosynthesis and the response to oxidative stress in Chlorella vulgaris

Qian, Haifeng; Chen, Wei; Sun, Liwei; Jin, Yuanxiang; Liu, Weiping; Fu, Zhengwei

doi:10.1007/s10646-009-0311-8

Cited by 77 publications

(46 citation statements)

References 33 publications

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“…The high toxicity of this compound has also been observed in studies involving the use of bacteria, small crustaceans, algae and aquatic plants. [8][9][10][11][12] Thus, its presence in the environment can cause adverse effects in aquatic and terrestrial organisms. Therefore, it is desirable for the development and optimization of viable technologies with a focus on disposal of such waste.…”

Section: Introductionmentioning

confidence: 99%

Degradation of the herbicide paraquat by photo-fenton process: optimization by experimental design and toxicity assessment

Trovó

Gomes

Machado

et al. 2013

J. Braz. Chem. Soc.

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Este trabalho descreve a influência e otimização dos reagentes de Fenton (concentração de Fe 2+ e H 2 O 2 ) na eficiência da mineralização do herbicida paraquat (PQT, 50 mg L -1 ) em água, após 60 min (equivalendo a 642 kJ L -1 de radiação UVA acumulada) de tratamento por processo foto-Fenton em escala de laboratório, usando planejamento composto central (CCD). Sob condições otimizadas, experimentos cinéticos foram feitos, avaliando a remoção do PQT, sua mineralização e toxicidade em escala de laboratório, usando irradiação artificial, e em planta piloto sob irradiação solar. A mesma eficiência de remoção e mineralização do PQT foram obtidas em ambos os reatores utilizados. A toxicidade das amostras, estimada em termos de mortalidade de Artemia salina, diminui simultaneamente com o decaimento da concentração de PQT, sugerindo a formação de intermediários de menor toxicidade. Dessa maneira, o processo foto-Fenton/solar pode ser considerado uma alternativa viável para o tratamento de águas residuais contendo PQT.This study describes the influence and optimization of Fenton's reagent (concentration of Fe ) in water, after 60 min (equivalent to 642 kJ L -1 of accumulated UVA radiation) treatment by photo-Fenton process in laboratory scale, using central composite design (CCD). Under optimized conditions, kinetic experiments were done, evaluating the PQT removal, its mineralization and toxicity in laboratory scale, using artificial irradiation, and in a pilot plant under solar irradiation. The same removal efficiency and mineralization of PQT were obtained in both reactors. The toxicity of the samples, estimated in terms of mortality of Artemia salina, decreases simultaneously with the decay of concentration of PQT, suggesting the formation of intermediates of lower toxicity. In this way, the solar photo-Fenton process can be considered as a viable alternative for the treatment of wastewater containing PQT.Keywords: pesticides, detoxification, pilot plant, wastewater treatment, solar light intensity IntroductionSince 2008 Brazil has overtaken the United States in pesticides consumption, becoming the largest consumer. 1 The herbicide paraquat dichloride (PQT, Figure 1) has been widely used for application in post-emergence of weeds and also as desiccant.2 Its residence time in soils can vary from 1.4 to 7.2 years depending on the concentration, soil characteristics (organic matter), temperature and rainfall.3 In river water samples, it has been observed that PQT is not easily microbiologically degraded, since, even after 56 days of incubation, more than 80% of the initial concentration remains unchanged, suggesting to PQT considerable recalcitrance. 4 In addition, PQT is polar, showing high solubility in water, as well as a low octanol-water partition coefficient (log K ow = -4.5), which provides a great mobility in some soils, arriving easily until the next water supplies.5 It has been found in the range of 2-12 mg L -1 in groundwater, 6 and, for example, at average concentration of 0.78 mg L -1 in surface waters ...

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Section: Introductionmentioning

confidence: 99%

Degradation of the herbicide paraquat by photo-fenton process: optimization by experimental design and toxicity assessment

Trovó

Gomes

Machado

et al. 2013

J. Braz. Chem. Soc.

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“…Among different herbicides, Paraquat (1,1'-dimethyl-4,4'-bipyridinium, PQ) is the most widely used herbicide in the world because of its greater efficiency and low cost (Qian et al 2009a;Moran et al 2010). It blocks photosynthesis by accepting electrons from photosystem I (PSI) and causes overproduction of reactive oxygen species (ROS) which caused alteration of the main biomolecule classes, leads to structural and func-1120 A.…”

Section: Introductionmentioning

confidence: 99%

“…It blocks photosynthesis by accepting electrons from photosystem I (PSI) and causes overproduction of reactive oxygen species (ROS) which caused alteration of the main biomolecule classes, leads to structural and func-1120 A. Sood et al tional changes in lipids, proteins, chlorophylls, and nucleic acids (Qian et al 2009a;Moran et al 2010;Sood et al 2011). Holst et al (1982 observed that bipyridilium and phenolic herbicides were detrimental to A. mexicana, causing up to 75% reduction in N 2 fixation.…”

Section: Introductionmentioning

confidence: 99%

Differential responses of hydrogen peroxide, lipid peroxidation and antioxidant enzymes in Azolla microphylla exposed to paraquat and nitric oxide

et al. 2012

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The present investigation was carried out to decipher the interplay between paraquat (PQ) and exogenously applied nitric oxide (NO) in Azolla microphylla. The addition of PQ (8 µM) increased the activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) by 1.7, 2.7, 3.9 and 1.9 folds respectively than that control in the fronds of Azolla. The amount of H2O2 was also enhanced by 2.7 times in the PQ treated plants than that of control. The supplementation of sodium nitroprusside (SNP) from 8-100 µM along with PQ, suppressed the activities of antioxidative enzymes and the amount of H2O2 compared to PQ alone. The drop in the activity of antioxidative enzymes -SOD, GPX, CAT and APX was highest (39.9%, 48.4%, 41.6% and 41.3% respectively) on the supplementation of 100 µM SNP with PQ treated fronds compared to PQ alone. The addition of NO scavengers along with NO donor in PQ treated fronds neutralized the effect of exogenously supplied NO. This indicates that NO can effectively protect Azolla against PQ toxicity by quenching reactive oxygen species. However, 200 µM of SNP reversed the protective effect of lower concentration of NO donor against herbicide toxicity. Our study clearly suggests that (i) SNP released NO can work both as cytoprotective and cytotoxic in concentration dependent manner and (ii) involvement of NO in protecting Azolla against PQ toxicity.

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“…Sun et al (2006) reported that phenanthrene rapidly accumulated in fish tissue and stimulated the production of free radicals in the liver of Carassius auratus. All of these are examples of the oxidative stress that may be induced by xenobiotics (Shi et al 2005;Qian et al 2009). However, limited studies have been undertaken concerning the production of ROS and the resulting oxidative stresses in aquatic plants in the presence of phenanthrene exposure.…”

Section: Discussionmentioning

confidence: 99%

Bioaccumulation and ROS generation in Coontail Ceratophyllum demersum L. exposed to phenanthrene

et al. 2010

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Phenanthrene bioaccumulation, induction free radicals and their consequent biochemical responses in coontail (Ceratophyllum demersum L.) were examined. Plants were exposed to different levels (0.01, 0.02, 0.05, 0.07 and 0.1 mg/l) of phenanthrene for 10 days. Results showed that the phenanthrene concentration in the plants was exponentially correlated to exposure concentration (R (2) = 0.958) and phenanthrene exposure significantly increased the total free radicals and superoxide anion in the plants. The activities of antioxidant enzymes and the contents of glutathione were determined. The superoxide dismutase (SOD) activity and reduced glutathione (GSH) content were inhibited, while the catalase (CAT), peroxidase (POD), glutathione-s-transferase (GST) activities and oxidized glutathione (GSSG) content were significantly induced. Changes in the contents of chlorophyll and malondialdehyde (MDA) indicated that the MDA content was enhanced after phenanthrene exposure and the contents of chlorophyll were significantly increased in the 0.01 mg/l group. These experimental data demonstrated that the bioaccumulation of phenanthrene induced the production of free radicals and ROS, and changed the antioxidant defense system, ultimately resulting in oxidative damage in C. demersum.

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Inhibitory effects of paraquat on photosynthesis and the response to oxidative stress in Chlorella vulgaris

Cited by 77 publications

References 33 publications

Degradation of the herbicide paraquat by photo-fenton process: optimization by experimental design and toxicity assessment

Degradation of the herbicide paraquat by photo-fenton process: optimization by experimental design and toxicity assessment

Differential responses of hydrogen peroxide, lipid peroxidation and antioxidant enzymes in Azolla microphylla exposed to paraquat and nitric oxide

Bioaccumulation and ROS generation in Coontail Ceratophyllum demersum L. exposed to phenanthrene

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