Alleviating versus stimulating effects of bicarbonate on the growth of Vallisneria natans under ammonia stress

Bicarbonate plays a crucial role in limiting the growth of submersed aquatic macrophytes in eutrophic lakes, and high ammonia is often toxic to macrophytes. In order to evaluate the combined effect of HCO₃ ^? and total ammonia (i.e., the total of NH₃ and NH₄ ⁺) on submersed macrophytes Vallisneria natans, the growth and physiological response of V. natans in the presence of HCO₃ ^? and ammonia were studied. The results showed that with the increase of ammonia, morphological parameters of V. natans declined. In contrast, increased HCO₃ ^? concentration stimulated the growth of V. natans, especially when the NH₄ ⁺-N/NO₃ ^?-N ratio was 1:7. High ammonia concentration induced excess free amino acids (FAA) accumulation and soluble carbohydrates (SC) depletion in plant tissues. However, the elevated HCO₃ ^? promoted the synthesis of SC and rendered the decrease of FAA/SC ratio. The results also suggested that HCO₃ ^? could partially alleviate the stress of ammonia, as evidenced by the decrease of FAA/SC ratio and the growth enhancement of V. natans when the ammonia concentration was 0.58 mg?L^?1. Given the fact that HCO₃ ^? is probably the dominant available carbon source in most eutrophic lakes, the ability of V. natans to use HCO₃ ^? for SC synthesis may explain the alleviating effect of HCO₃ ^? on V. natans under ammonia stress.     

Protective effects of melatonin and vitamin E in acetamiprid-induced nephrotoxicity

Environmental Science and Pollution Research - Investigation of probable toxic effects of acetamiprid (ACMP) on kidney and comparative analysis of the probable protective effects of vitamin E and...     

Protective effects of isoflavone on some biochemical parameters affected by cypermethrin in male rabbits

Effect of isoflavone on cypermethrin-induced changes in enzyme activities and free radicals was studied in plasma, liver, brain and testes of male New Zealand White rabbits. Rabbits were orally given sublethal dose of cypermethrin (24 mg/kg BW; 1/100 LD50), while isoflavone (2 mg/kg BW) was given alone or in combination with cypermethrin. The tested doses were given to rabbits every other day for 12 weeks. Results obtained showed that cypermethrin significantly (P < 0.05) induced free radicals in plasma, liver, brain and testes. The activities of glutathione S-transferase (GST) (liver, brain and testes), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (liver and testes), and alkaline phosphatase (AlP) (liver) were significantly (P < 0.05) decreased due to cypermethrin administration. Contrariwise, the activities of GST, AST, ALT and AIP were increased in plasma. The activity of acetylcholinesterase (AChE) did not change in plasma and brain of treated rabbits with cypermethrin. Isoflavone alone significantly (p < 0.05) decreased the levels of free radicals in plasma, liver, brain and testes, while did not produce any significant effect on the investigated enzymes. However, isoflavone is able to reverse the changes in enzyme activities due to the effect of cypermethrin. Results concluded that isoflavone confers marked protection against cypermethrin-induced oxidative stress in rabbit's plasma, liver, brain and testes.     

Selective effects of fenitrothion on murine splenic T-lymphocyte populations and cytokine/granzyme production

The aim of this study was to investigate in vitro effects of fenitrothion (FNT) on mouse splenic lymphocytes. Here, naïve mice had their spleens harvested and splenocytes isolated. After exposure to FNT for 48 hr: splenocyte viability was measured using a tetrazolium dye assay; cell phenotypes, i.e., B-cells (CD19⁺), T-cells (CD3⁺), and T-cell subsets (CD4⁺ and CD8⁺), were quantified by flow cytometry; and, production of cytokines/granzyme-B was assessed via enzyme-linked immunosorbent assay. The ability for FNT to induce oxidative stress in the cells was evaluated by measuring hydroxyl radical (·OH) and malondialdehyde (MDA) production and changes in glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity. The results showed that FNT significantly inhibited splenocyte proliferation, and decreased production of interleukin (IL)-2, interferon gamma, IL-4, and granzyme B, but had no impact on IL-6 production. FNT also selectively decreased splenic T-cell levels but did not induce changes in CD19⁺ B-cells. Further, within the T-cell populations, percentages of CD3⁺, CD4⁺, and CD8⁺ T-cells (particularly CD8⁺ T-cells) were reduced. Lastly, FNT selectively increased MDA and ·OH production and inhibited SOD and GSH-Px activities in the splenic lymphocytes. These findings suggest that, due to oxidative damage, FNT selectively inhibits splenic T-lymphocyte survival and cytokine/granzyme production in vitro.     

Deleterious effects of cypermethrin on rat liver and kidney: Protective role of sesame oil

The involvement of reactive oxygen species (ROS) has been implicated in the toxicity of various pesticides. Our study was designed to investigate the induction of oxidative stress by cypermethrin; a Type II pyrethroid in rat liver and kidney. In addition, the protective role of sesame oil against the toxicity of cypermethrin was investigated. Animals were divided into four equal groups; the first group used as control while groups 2, 3 and 4 were treated with sesame oil (5 mL/kg b.w), cypermethrin (12 mg/kg b.w) and the combination of both sesame oil (5 mL/kg b.w) plus cypermethrin (12 mg/kg b.w), respectively. Rats were daily administered with their respective doses for 30 days by gavage. Repeated oral administration of cypermethrin was found to reduce the level of glutathione (GSH) and the activities of the antioxidant enzymes. While, the level of TBARS was elevated indicating the presence of oxidative stress. The activities of LDH, AST and ALT were decreased in the liver extract while increased in the plasma of the cypermethrin-treated group. Also, the levels of urea and creatinine were significantly increased after treatment with cypermethrin. Liver and kidney injury was confirmed by the histological changes. In conclusion, the administration of sesame oil provided significant protection against cypermethrin-induced oxidative stress, biochemical changes, histopathological damage and genomic DNA fragmentation.     

重碳酸盐碱度对电吸附设备除盐性能影响的研究

为了系统地考察重碳酸盐碱度对电吸附设备除盐性能的影响,利用小型电吸附模块对含有不同重碳酸盐碱度的原水水质进行处理.实验结果表明,随着其含量从170 mg/L增加到400 mg/L,电吸附设备的除盐率明显下降.通过对起始工作电流降低这一变化作理论分析,认为重碳酸盐碱度在电吸附模块内部积存结垢是影响电吸附设备除盐性能的重要原因,并通过实验证实其与钙离子共同作用导致了结垢.     

Protective effects of thymoquinone and diallyl sulphide against malathion-induced toxicity in rats

Environmental Science and Pollution Research - Malathion is a potent organophosphate insecticide that inhibits acetylcholinesterase (AChE) enzyme. Our experimental objective was to investigate the...     

Ecotoxicological evaluation of sodium fluoroacetate on aquatic organisms and investigation of the effects on two fish cell lines

Sodium monofluoroacetate (compound 1080) is one of the most potent pesticides. It is also a metabolite of many other fluorinated compounds, including anticancer agents, narcotic analgesics, pesticides or industrial chemicals. Other sources of water contamination are the atmospheric degradation of hydrofluorocarbons and hydrochlorofluorocarbons. However, there is little information available about the adverse effects of sodium fluoroacetate in aquatic organisms. Firstly, the bacterium Vibrio fischeri (decomposer), the alga Chlorella vulgaris (1st producer) and the cladoceran Daphnia magna (1st consumer) were used for the ecotoxicological evaluation of SMFA. The most sensitive models were C. vulgaris and D. magna, with a NOAEL of 0.1 and an EC50 of 0.5 mM at 72 h, respectively. According to the results after the acute exposure and due to its high biodegradation rate and low bioaccumulation potential, sodium fluoroacetate is most unlikely to produce deleterious effects to aquatic organisms. Secondly, two fish cell lines were employed to investigate the effects and mechanisms of toxicity in tissues from 2nd consumers. The hepatoma fish cell line PLHC-1 was more sensitive to SMFA than the fibroblast-like fish cell line RTG-2, being the uptake of neutral red the most sensitive bioindicator. Lysosomal function, succinate dehydrogenase and acetylcholinesterase activities were inhibited, glucose-6-phosphate dehydrogenase activity was particularly stimulated, and metallothionein and ethoxyresorufin-O-deethylase levels were not modified. Intense hydropic degeneration, macrovesicular steatosis and death mainly by necrosis but also by apoptosis were observed. Moreover, sulphydryl groups and oxidative stress could be involved in PLHC-1 cell death induced by SMFA more than changes in calcium homeostasis.     

Protective effects of seaweeds against liver injury caused by carbon tetrachloride in rats

Three species of seaweeds collected from Tung Ping Chau, Hong Kong, were screened for their hepatoprotective activity using carbon tetrachloride (CCl4)-induced liver injury in the rat as a model of chemical hepatitis. A single oral dose of 1.25 ml/kg of CCl4 was able to produce significantly elevated levels of serum glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transminase (GOT). Administration of 150, 300 and 600 mg/kg of aqueous extracts from Myagropsis myagroides, Sargassum henslowianum and S. siliquastrum, respectively, significantly reduced the CCl4-induced acute elevation in the levels of GPT and GOT in rats. The same result was also seen in the histopathological study of liver tissue. The seaweed crude extracts probably acted to protect against CCl4-induced liver injury through their antioxidant properties.     

Protective effects of thymoquinone against acrylamide-induced liver,kidney and brain oxidative damage in rats

Environmental Science and Pollution Research - Acrylamide (AA), an industrial monomer, may cause multi-organ toxicity through induction of oxidative stress and inflammation. The antioxidant...     

Protective effects of dietary betaine on intestinal barrier function and cecal microbial community in indigenous broiler chickens exposed to high temperature environment

Environmental Science and Pollution Research - High temperature environment causes reduction in productivity in broilers by disrupting the intestinal barrier function. This study aimed to...     

The influence of metam sodium on soil respiration

Abstract

A laboratory experiment was performed in order to evaluate the extent to which metam sodium (MS) applied at two different recommended rates and its degradation product, methyl isothiocyanate ( MITC ), affect soil respiration. Results suggest that MS degradation to MITC was complete within 4 hours and that MITC decomposed quickly in a few days, except in the soil containing high organic matter where it was still present after 15 days. Following the addition of MS, a lag phase appeared in CO₂‐C evolution in the soil. It was longer for the higher dose of MS added and for the two soils with low organic C content. The dynamics of the process was described by the Bonde and Rosswall model and by the Gompertz RS E model for the untreated and the MS‐treated soils, respectively.     

The influence of metam sodium on soil respiration

A laboratory experiment was performed in order to evaluate the extent to which metam sodium (MS) applied at two different recommended rates and its degradation product, methyl isothiocyanate (MITC), affect soil respiration. Results suggest that MS degradation to MITC was complete within 4 hours and that MITC decomposed quickly in a few days, except in the soil containing high organic matter where it was still present after 15 days. Following the addition of MS, a lag phase appeared in CO2-C evolution in the soil. It was longer for the higher dose of MS added and for the two soils with low organic C content. The dynamics of the process was described by the Bonde and Rosswall model and by the Gompertz RS E model for the untreated and the MS-treated soils, respectively.     

Mobilization of arsenic from subsurface sediments by effect of bicarbonate ions in groundwater

Arsenic leaching by bicarbonate ions has been investigated in this study. Subsurface sediment samples from Bangladesh were treated with different carbonate and bicarbonate ions and the results demonstrate that the arsenic leaching efficiency of the carbonate solutions decreased in the order of Na2CO3>NaHCO3>BaCO3>MnCO3. Sodium carbonate and bicarbonate ions extracted arsenic most efficiently; Na2CO3 leached maximum 118.12 microg/l of arsenic, and NaHCO3, 94.56 microg/l of arsenic from the Ganges delta sediments after six days of incubation. The arsenic concentrations extracted in the batch experiments correlated very well with the bicarbonate concentrations. The kinetics study of arsenic release indicates that arsenic-leaching rate increased with reaction time in bicarbonate solutions. Bicarbonate ions can extract arsenic from sediment samples in both oxic and anoxic conditions. A linear relationship found between arsenic contents in core samples and those in leachates suggests that dissolved arsenic concentration in groundwater is related to the amount of arsenic in aquifer sediments. In batch experiment, bicarbonate solutions effectively extracted arsenic from arsenic adsorbed iron oxyhydroxide, reflecting that bicarbonate solutions may mobilize arsenic from iron and manganese oxyhydroxide in sediments that are ubiquitous in subsurface core samples. Carbonate ion may form complexes on the surface sites of iron hydroxide and substitute arsenic from the surface of minerals and sediments resulting in release of arsenic to groundwater. Like in the batch experiment, arsenic and bicarbonate concentrations in groundwater of Bangladesh correlated very well. Therefore, bicarbonate leaching is presumed to be one important mechanism to mobilize arsenic in bicarbonate dominated reducing aquifer of Bangladesh and other parts of the world as well.     

Attenuation of sodium arsenite-induced cardiotoxicity and neurotoxicity with the antioxidant,anti-inflammatory,and antiapoptotic effects of hesperidin

Environmental Science and Pollution Research - In the scope of the study, the protective effect of hesperidin (HES), a flavanone glycoside, was investigated against sodium arsenite (NaAsO2, SA)...     

含盐量对好氧颗粒污泥形成过程的影响

研究了不同含盐梯度废水下好氧颗粒污泥的形成过程.在反应器 R1 中,其含盐量一直维持 1%,其颗粒成中空结构;在 R2、R3 中,其含盐量由 1%提高到 2.5%时,其颗粒发生膨胀破碎;在 R3 中,其含盐量由 2.5%提高到 5%时,其颗粒由疏松变为密实.另外,溶解氧消耗速率(SOUR)随着含盐量的增加而降低.在含盐量为 2.5%时,好氧颗粒污泥的耐盐菌与非耐盐菌均处于不利的生长环境,此时好氧颗粒污泥处于最不稳定的状态,容易发生解体.     

次氯酸钠处理含尿素废水实验研究

用次氯酸钠处理废水中的尿素,考察了反应温度、初始pH值、搅拌转速、NaClO投加量、反应时间、气量对尿素去除率的影响.研究结果表明,未采用空气吹脱时,较适宜的处理条件:反应温度为40℃,初始pH值为6～7,NaClO投加量为3.19～4.29 g/g,反应时间为20 min.采用空气吹脱能有效提高尿素去除效果,在相同条...     

Effect of sodium arsenate on microbial growth in a chemostat

Abstract

Microbial transformation of sodium arsenate, the wood preservative and insecticide, is important in assessing the environmental impact of this pesticide. Recent studies using batch culture techniques have shown that arsenate is metabolized to more toxic end products. This study investigated the effect of the chemical on the microbial cells themselves using continuous flow cultures to examine the effect of arsenate on the growth and maintenance requirements of the microbes. Cell yield was lower and maintenance requirements higher at 100 pg/ml arsenate than at 10 μg/ml indicating a greater expenditure of energy by the cells to maintain homeostasis’.     

Determination of cytotoxicity of nephrotoxins on murine and human kidney cell lines

The present study investigates renal inner medullary collecting duct (mIMCD3) cells and human embryonic kidney cells (HEK293) for evaluation of cytotoxicity of nephrotoxic compounds. The 24 h LC(50) values for cisplatin, paraquat and ibuprofen in mIMCD3 cells were 135, 155 and 3600 microM, respectively. The 24 h LC(50) values for paraquat and ibuprofen in HEK293 cells were 180 and 1000 microM, respectively. Effects of hyperosmolality on cytotoxicity of paraquat were additive in mIMCD3 cells. These data demonstrate that renal hyperosmolality has an additive effect on cytoxicity of paraquat.