一体化氧化沟处理污水的试验

本文设计开发了一种新型的一体化沟系统，对其进行了清水模拟试验和污水处理试验。清水试验结果表明，这种一体化氧化沟内沉淀池具有良好的固液分离特性，当水力停留时间大于１２小时，沟内ＳＳ在２－５ｇ／ｌ时，出水ＳＳ均小于５０ｍｇ／ｌ，出水ＳＳ相对于沟内ＳＳ的去除率大于９８％。污水试验结果表明，系统有较强的去除有机物的能力，当水力停留时间为２１小时时，ＣＯＤ去除率可达８０％以上，ＢＯＤ５去除率在９０％以上。出     

EDTA对汞毒害下小麦幼苗细胞膜及体内保护系统的影响

研究表明，向含汞污水中加入ＥＤＴＡ能使汞引起的小麦幼苗细胞膜透性，膜脂质过氧化水平，ＳＯＤ活性，可溶性糖及可溶性蛋白质含量的增加和ＣＡＴ活性的降低得以恢复，汞对幼苗的毒害减轻。     

活性硅酸混凝剂PFASSC处理造纸废水

利用硅酸钠、硫酸铝、三氯化铁和硫酸为主要原料制备了复合型活性硅酸混凝剂ＰＦＡＳＳＣ并对造纸废水进行了处理，得到活性硅酸混凝剂ＰＦＡＳＳＣ最佳配方为：ＰＨ＝２．０（Ｆｅ＾３＋＋Ａｌ＾２）／ＳｉＯ２（摩尔比）＝１．５，Ｆｅ＾３＋／Ａｌ＾３＋（摩尔比）＝１．０，与常用混凝剂相比，ＰＦＡＳＳＣ混凝剂处理造纸废水对除浊、脱色和去除ＣＤＤＣｒ有更加优良的性能。     

厌氧—好氧法处理渗滤液与城市污水混合废水的可行性

彩厌氧－好氧工艺对不同浓度的垃圾填埋场渗滤液与城市污水在不同混合比（ＶＳＨ：ＶＣＨ）时的处理效果及可行性进行了研究,厌氧段采用新型ＡＢＲ反应器并将控制在水解酸化阶段。研究表明,当原渗滤液ＣＯＤ〈５５００ｍｇ／Ｌ时,ＶＳＨ：ＶＣＨ达４：６是可行的,其稳定运行时的ＣＯＤ和ＢＯＤ５去除率可分别达８８．９％和９６．８％当原渗滤液ＣＯＤ≥６５００～８８００ｍｇ／Ｌ时,须将ＶＳＨ：ＶＣＨ控制在２．８以内。     

SBR法处理印染废水的研究

应用ＳＢＲ法、ＰＡＣ－ＳＢＲ法，微电解－ＳＢＲ法对印染废水进行了对比处理试验研究。试验结果表明：微电解－ＳＢＲ法处理效果优于其它两种方法，当进水ＣＯＤ＝１０００～１６００ｍｇ／Ｌ，色度＝２００～８００倍，ＢＯＤ５＝２５０～４００ｍｇ／Ｌ时．ＣＯＤ去除率在８５％左右，ＢＯＤ５去除率和脱色率均在９０％以上，出水达到排放标准。     

碱解─A/A/0─生物炭处理有机磷农药废水

通过对有机磷农药废水成份及其机理的分析，提出了碱解－Ａ／Ａ／０－生物炭处理工艺。在适当的污泥回流比、混合液回流比条件下，控制曝气池中Ｎ_（ＴＯＣ）≤０．１０ ｋｇ·ＢＯＤ_５／ｋｇＭＬＳＳ·ｄ、ＮＨ_３≤０．０８ ｋｇＮＨ_３－Ｎ／ｋｇＭＬＳＳ·ｄ，厌氧池中Ｎ_（Ｔｏｃ）≤（０．１０．２５）ｋｇ ＢＯＤ_5／ｋｇＭＬＳＳ·ｄ及兼氧池中Ｎ_（ＮＤ）_３≤０．０８ ｋｇＮＯ_３－Ｎ／ ｋｇＭＬＬＳＳ·ｄ时，可同时获得最高的ＴＮ、ＴＰ及ＴＯＣ的去除效果，并使出水达一级排入标准。     

施肥过程中的污染控制

农业生产造成的自身污染是一个不可忽略的环境问题,化肥施用不当造成植物体内硝酸盐含量增加以及水源的污染,城市活性污沁的农用处理,扩大了农田重金属污染的途径和范围,因此要提介科学种田,合肥施肥,以减轻对农业环境的污染。     

兼氧接触工艺处理造纸中段废水中间试验的研究

采用中试规律的兼氧接触工艺处理造纸中段废水，当处理水量为４．８ｍ＾３／ｄ，水力停留时间３～４ｈ，气水比３：１，进水ＰＨ８～９．５，平均ＣＯＤ浓度为１６４１．６ｍｇ／ｌ，ＢＯＤ５５１６．１ｍｇ／ｌ，ＳＳ６８８．４ｍｇ／ｌ的条件下，处理后出水ｐＨ７．５左右，平均ＣＯＤ浓度为１０５９．８ｍｇ／ｌ，去除率３４．９％，ＢＯＤ５２４６．５ｍｇ／ｌ，去除率５２．１％，ＳＳ１６１．９ｍｇ／ｌ，去除率为７７．１％。     

钛白水解废酸治理工艺

提出了利用钛白粉生产排放的２０％Ｈ２ＳＯ４与废铁皮制备ＦｅＳＯ４这一新的钛白废酸治理原理和工艺，为国内Ｈ２ＳＯ４生产钛白粉生产治理废酸污染，提供了一条途径。     

SBR工艺处理制革废水的初探

ＳＢＲ工艺具有许多优点。现有活性污泥处理工艺经适当调整，采用ＳＢＲ工艺对制革废水的处理进行了试验，实践表明，ＳＢＲ曝气池ＣＯＤＣＲ的去除率可达到７０％以上。并探讨了如何进一步提高ＣＯＤＣＲ的去除率。     

The redox state and activity of superoxide dismutase classes in Arabidopsis thaliana under cadmium or copper stress

The redox state of glutathione and ascorbate as well as the activity of superoxide dismutase classes were determined in leaves of Arabidopsis thaliana grown for seven days in the nutrient solution containing 0, 5 and 50 microM Cd or Cu excess. A decrease in GSH/GSSG ratio was found in plants under Cd and Cu stress. In the plants exposed to Cu stress the activity of all SOD classes increased. However, in the plants treated with Cd the activity of FeSOD and MnSOD was elevated, but CuZnSOD activity was diminished in comparison with control. In these plants the activity of SOD classes was dependent on both the GSH/GSSG and AA/DHA ratios, while in those exposed to Cu excess - on the GSH/GSSG ratio. Differences were shown in the changes both in redox state and activity of SOD classes caused by the metals differing in physiochemical properties. Moreover, relationships between changes in SOD class activities and ROS levels were discussed.     

Lead induced changes in antioxidant metabolism of horsegram (Macrotyloma uniflorum (Lam.) Verdc.) and bengalgram (Cicer arietinum L.)

One-month old horsegram (Macrotyloma uniflorum (Lam.) Verdc. cv VZM1) and bengalgram (Cicer arietinum L. cv Annogiri) were exposed to different regimes of lead stress as Pb(NO3)2 at 0, 200, 500 and 800 ppm concentrations. The extent of oxidative damage as the rate of lipid peroxidation, antioxidative response and the accumulation of lead in roots and shoots of both plants were evaluated after 12 days of lead stress. Lead (Pb) treated plants showed increased levels of lipid peroxidation as evidenced from the increased malondialdehyde content coupled with the increase in the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), glutathione S-transferase (GST) compared to control (untreated) plants. Lead stress caused significant changes in the activity of antioxidative enzymes. The effect of lead was found to be concentration dependent. Higher concentration of lead (800 ppm) resulted 2- to 3-fold increase in SOD, catalase and peroxidase activities, 3- to 5-fold increase in GR activity and 3- to 4-fold increase in GST activity in roots and leaves of both horsegram and bengalgram plants. Lead stress caused a significant increase in the rate of peroxidation as showed in the levels of malondialdehyde content in roots and leaves of both plant species. Horsegram registered lower Pb accumulation than bengalgram, however localization of Pb was greater in roots than leaves in both plants. In general, lipid peroxide levels and antioxidative enzyme activities were higher in horsegram than bengalgram and also more in roots than leaves which best concordance with the lead contents of both the plants and organs. These results suggest that Pb toxicity causes oxidative stress in plants and the antioxidative enzymes SOD, CAT, POD, GR, GST could play a pivotal role against oxidative injury.     

Atrazine promotes biochemical changes and DNA damage in a Neotropical fish species

The effects of Atrazine, an herbicide used worldwide and considered as a potential contaminant in aquatic environments, were assessed on the Neotropical fish Prochilodus lineatus acutely (24 and 48 h) exposed to 2 or 10 μg L⁻¹ of atrazine by using a set of biochemical and genetic biomarkers. The following parameters were measured in the liver: activity of the biotransformation enzymes ethoxyresorufin-O-deethylase (EROD) and glutathione S transferase (GST), antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), content of reduced glutathione (GSH), generation of reactive oxygen species (ROS) and occurrence of lipid peroxidation (LPO); in brain and muscle the activity of acetylcholinesterase (AChE) and DNA damage (comet assay) on erythrocytes, gills and liver cells. A general decreasing trend on the biotransformation and antioxidant enzymes was observed in the liver of P. lineatus exposed to atrazine; except for GR, all the other antioxidant enzymes (SOD, CAT and GPx) and biotransformation enzymes (EROD and GST) showed inhibited activity. Changes in muscle or brain AChE were not detected. DNA damage was observed in the different cell types of fish exposed to the herbicide, and it was probably not from oxidative origin, since no increase in ROS generation and LPO was detected in the liver. These results show that atrazine behaves as enzyme inhibitor, impairing hepatic metabolism, and produces genotoxic damage to different cell types of P. lineatus.     

Effect of heavy metal stress on antioxidative enzymes and lipid peroxidation in leaves and roots of two mangrove plant seedlings (Kandelia candel and Bruguiera gymnorrhiza)

The effects of multiple heavy metal stress on the activity of antioxidative enzymes and lipid peroxidation were studied in leaves and roots of two mangrove plants, Kandelia candel and Bruguiera gymnorrhiza, grown under control (10 per thousand NaCl nutrient solution) or five levels of multiple heavy metal stress (10 per thousand NaCl nutrient solution containing different concentration of Pb2+, Cd2+, and Hg2+). Leaves and roots of control and heavy metal-stressed plants were harvested after two months. In leaves of heavy metal-stressed plants superoxide dismutase (SOD) and peroxidase (POD) activities fluctuated in different stress levels compared to the control, while catalase (CAT) activity increased with stress levels in K. candel, but remained unchanged in leaves of B. gymnorrhiza. In comparison with the control, the dynamic tendency of SOD, CAT, and POD activities in roots of heavy metal-stressed plants all ascended, and then declined. The increase in enzyme activities demonstrated that K. candel is more tolerant to heavy metals than B. gymnorrhiza. Lipid peroxidation was enhanced only in leaves of heavy metal-stressed B. gymnorrhiza. These results indicate that in heavy-metal stress antioxidative activities may play an important role in K. candel and B. gymnorrhiza and that cell membrane in leaves and roots of K. candel have greater stability than those of B. gymnorrhiza. For pollution monitoring purposes, POD activity in roots and leaves maybe serve as a biomarker of heavy metal stress in K. candel, while lipid peroxidation maybe serve as biomarker in B. gymnorrhiza.     

Physiological effects of tetracycline antibiotic pollutants on non-target aquatic Microcystis aeruginosa

This study aimed to evaluate the aquatic toxicity of three typical tetracycline antibiotics, including tetracycline, oxytetracycline, and chlortetracycline, on the cyanobacterium Microcystis aeruginosa. The cell density, chlorophyll a content, protein content, and enzymatic antioxidant activities were determined. The results showed that the cell growth was significantly inhibited by the three compounds at a low concentration. The chlorophyll a and protein content decreased significantly after exposure to 0.05 mg L^?1 of each compound for 9 d. When exposed to 0.2–1 mg L^?1 of tetracycline, the superoxide dismutase (SOD) activity increased, but peroxidase (POD) and catalase (CAT) activities decreased. In contrast, when exposed to oxytetracycline and chlortetracycline at different concentrations ranging from 0.2 to 1 mg L^?1 and from 0.01 to 0.05 mg L^?1, the SOD activity decreased, but the POD and CAT activities increased. These findings indicate that tetracycline antibiotics influence cell growth and protein synthesis, and they also induce oxidative stress in M. aeruginosa at environmentally similar concentrations. Thus, this study may provide further insights into the toxic effects of tetracycline antibiotics and the controlled use of antibiotics.     

Physiological and molecular responses of the earthworm <Emphasis Type="Italic">Eisenia fetida</Emphasis> to polychlorinated biphenyl contamination in soil

Polychlorinated biphenyls (PCBs) are a class of man-made organic compounds ubiquitously present in the biosphere. In this study, we evaluated the toxic effects of different concentrations of PCBs in two natural soils (i.e. red soil and fluvo-aquic soil) on the earthworm Eisenia fetida. The parameters investigated included anti-oxidative response, genotoxic potential, weight variation and biochemical responses of the earthworm exposed to two different types of soils spiked with PCBs after 7 or 14 days of exposure. Earthworms had significantly lower weights in both soils after PCB exposure. PCBs significantly increased catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (POD) activity in earthworms exposed to either soil type for 7 or 14 days and decreased the malondialdehyde (MDA) content in earthworms exposed to red soil for 14 days. Of the enzymes examined, SOD activity was the most sensitive to PCB stress. In addition, PCB exposure triggered dose-dependent coelomocyte DNA damage, even at the lowest concentration tested. This response was relatively stable between different soils. Three-way analysis of variance (ANOVA) showed that the weight variation, anti-oxidant enzyme activities, and MDA contents were significantly correlated with exposure concentration or exposure duration (P < 0.01). Furthermore, weight variation, CAT activity, and SOD activity were significantly affected by soil type (P < 0.01). Therefore, the soil type and exposure time influence the toxic effects of PCBs, and these factors should be considered when selecting responsive biomarkers.     

Relationship between leaf antioxidants and ozone injury in Nicotiana tabacum ‘Bel-W3’ under environmental conditions in São Paulo,SE – Brazil

Previous studies have reported that the extent of leaf injury in Nicotiana tabacum “Bel-W3” exposed to environmental conditions in the city of São Paulo is influenced by weather conditions. This influence may occur by means of antioxidant responses. Thus, this study aimed to evaluate whether daily antioxidant responses to environmental variations interfere on the progression of leaf injury on plants of this cultivar during their exposure in a state park of São Paulo and to determine a linear combination of variables, among antioxidants and environmental factors, which mostly explain this visible response. Plants were exposed at the mentioned site for 14 days in four different experiments. During each experiment, three plants were daily sampled to determine the accumulated percentage of leaf area affected by necrosis and antioxidant responses (concentrations of total ascorbic acid (AA) and activity of superoxide dismutase (SOD) and peroxidases (POD)). Ozone concentrations and weather conditions were also daily measured. Pearson correlations and multivariate analyses assessed the relationship between biological and environmental variables. Leaf injury appeared between the 3rd and 6th days of exposure and increased over the exposure periods. The daily concentrations of AA tended to decrease with time of exposure in all experiments, but the activity of SOD and POD oscillated during plant exposure. Positive correlations were observed between AA or SOD and O₃ concentrations, as well as negative correlations between AA and air temperature. The increasing percentage of leaf necrosis across the whole period was explained by decreasing levels of AA 2 days before injury estimation and by higher O₃ concentrations 5 days before (R² = 0.36; p < 0.001). The use of N. tabacum Bel-W3 as a bioindicator can be restricted by leaf antioxidant responses to both atmospheric contamination and weather conditions.     

Toxicity of copper excess on the lichen Dermatocarpon luridum: antioxidant enzyme activities

The aim of this study was to investigate the toxicity of copper on the aquatic lichen Dermatocarpon luridum focusing on the activities of some antioxidant enzymes. Investigations were conducted using increasing copper concentrations (0.00, 0.25, 0.50, 0.75 and 1.00 mM CuSO(4) x 5H(2)O) in synthetic freshwater that emulated the major ion compositions of its natural water biota; time course measurement was 0, 3, 6, 12, 24 and 48 h. The copper concentration in thalli increased with its increase in the medium and the duration of treatment. Copper induced lipid peroxidation, measured using the hydroperoxi-conjugated dienes (HPCD) concentration. The decrease in the protein concentrations was similar in thalli exposed to copper concentrations above 0.50 mM and the decrease was twice lower in thalli exposed to 0.25 mM copper. The activities of antioxidant enzymes measured were differently affected by copper excess. For 0.25 mM copper, the activities of SOD (superoxide dismutase) and APX (ascorbate peroxidase) were unchanged when compared with unstressed thalli whereas the CAT (catalase) activity increased and the GR (glutathione reductase) activity decreased. The activities of SOD and APX increased in thalli exposed to concentrations above 0.50mM copper. The CAT activity increased after the first 3h of experiments at these concentrations and then decreased with the duration of treatment at an activity lower than in the unstressed plant. Whereas the APX activity increased, the GR activity similarly decreased for the copper concentration tested whatever the duration of the experiment.     

Nitrogen fertilizer improves boron phytoextraction by Brassica juncea grown in contaminated sediments and alleviates plant stress

In this study we evaluated the effect of different fertilizer treatments on Brassica plants grown on boron-contaminated sediments. Experiments were conducted in the laboratory and on the lysimeter scale. At laboratory scale (microcosm), five different fertilizers were tested for a 35-d period. On the lysimeter scale, nitrogen fertilization was tested at three different doses and plants were allowed to grow until the end of the vegetative phase (70 d). Results showed that nitrogen application had effectively increased plant biomass production, while B uptake was not affected. Total B phytoextracted increased three-fold when the highest nitrogen dose was applied. Phytotoxicity on Brassica was evaluated by biochemical parameters. In plants grown in unfertilized B-contaminated sediments, the activity of antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and pyrogallol peroxidase (PPX) increased, whereas catalase (CAT) decreased with respect to control plants. Addition of N progressively mitigated the alteration of enzymatic activity, thus suggesting that N can aid in alleviating B-induced oxidative stress. SOD activity was restored to control levels just at the lowest N treatment, whereas the CAT inhibition was partially restored only at the highest one. N application also lowered the B-induced increase in APX and PPX activities. Increased glutathione reductase activity indicated the need to restore the oxidative balance of glutathione. Data also suggest a role of glutathione and phytochelatins in B defense mechanisms. Results suggest that the nitrogen fertilizer was effective in improving B phytoextraction by increasing Brassica biomass and by alleviating B-induced oxidative stress.     

Antioxidant enzyme activities as affected by trivalent and hexavalent chromium species in Fontinalis antipyretica Hedw

The detoxification mechanisms of the aquatic moss, Fontinalis antipyretica Hedw., exposed to Cr was analyzed. In addition, the influence of Cr salts (as Cr nitrate, chloride and potassium bichromate) on these mechanisms has also been studied. The activity of antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1.), catalase (EC 1.11.1.6.), ascorbate peroxidase (APX, EC 1.11.1.11.), guaiacol peroxidase (GPX, EC 1.11.1.7.) and glutathione reductase (GR, EC 1.6.4.2.) increased in plants treated with Cr concentrations ranging from 6.25x10(-5) to 6.25mM when given as Cr(NO(3))(3). Antioxidant enzymes responded to the other two salts CrCl(3) and K(2)Cr(2)O(7) only with Cr concentrations higher than 6.25x10(-2)mM. Glutathione level and GSSG/GSH ratio also responded to Cr exposure but no dose-effect relationship could be observed. Moreover, two unknown thiol compounds were observed in mosses exposed to the highest Cr concentrations. Effects on chlorophyll contents and chlorophyll a/b ratios were also shown even at low Cr concentrations. Our results indicated that environmentally realistic concentrations of Cr could lead to impairment of the cellular activity towards F. antipyretica and that Cr(III), when present as a nitrate salt, was as harmful as Cr(VI).