Fusarium wilt of cucumber caused by the fungus, Fusarium oxysporum, is one of the most destructive soilborne diseases and can result in serious economic loss. No efficient fungicide is currently available to control the disease. The aim of this study was to examine the disease suppression ability of pig manure and sludge composts in peat-based container media and explore the possible disease suppression mechanisms. Pig manure and sewage sludge compost were made in laboratory-scale tanks. Plant growth media were formulated with peat mixture and compost (or 60 °C heated compost) in a 4:1 ratio (v/v). Cucumber seedlings were artificially inoculated with F. oxysporum conidia (5 × 105 conidia mL−1) by the root-dip method. Cucumber Fusarium wilt was effectively suppressed in sludge compost-amended media, while the disease suppression effect of pig manure compost was limited. The ammonia levels in the manure compost-amended media were significantly higher than those of sludge compost-amended media, which could explain its lower disease suppression ability. Heated composts behaved similarly with respect to disease suppression. Adding composts increased microbial biomass, microbial activity, and the microbial diversity of the growth media. PCR-DGGE results indicated that the fungal community had a significant correlation to the disease severity. The artificially inoculated pathogen was retrieved in all treatments and one possible biocontrol agent was identified as a strain of F. oxysporum by phylogenetic analyses. The results indicated that the sludge compost used in this study could be applied as a method for biocontrol of cucumber Fusarium wilt.

PURPOSE: This research is on the evaluation of biosorption capability of the core of Artocarpus odoratissimus (Tarap), grown in Brunei Darussalam, towards Cd(II) and Cu(II) ions present in synthetic solutions, and to characterize the surface of Tarap particles. METHODS: Thermogravimetric analysis and surface titrations were conducted to characterize the surface of dried Tarap core particles. Atomic absorption spectroscopic measurements were conducted to determine the extent of removal of Cd(II) and Cu(II) under different experimental conditions. RESULTS: Mass reductions associated with many exothermic reaction peaks were observed beyond 200°C up to 650°C indicating the combustion of organic matter in Tarap. Dried particles of core of Tarap bear a negative surface charge promoting strong interaction towards positively charged ions, such as Cu(II) and Cd(II). Biosorption of the two metal ions on Tarap, which is relatively high beyond pH = 4, occurs within a short period of exposure time. The extent of biosorption is enhanced by acid treatment of the biosorbent, and further it does not significantly depend on the presence of nonreacting ions up to an ionic strength of 2.0 M. CONCLUSION: Strong attraction between each metal ion and the biosorbent is attributed to the negative surface charge on the biosorbent within a broad pH range. Acid treatment of the biosorbent improves sorption characteristics, suggesting that ion exchange plays an important role in the metal ion—biosorbent interaction process.

Greenhouse and field studies were performed to examine the growth responses and possible phytoremediation capacity towards heavy metals of several Brassicaceae (Brassica alba, Brassica carinata, Brassica napus and Brassica nigra) and Poaceae (durum wheat and barley). Soils used featured total concentrations of Cr, Cu, Pb and Zn largely exceeding the maximum levels permitted by the Italian laws. Different organic amendments were tested such as a compost and the plant growth-promoting rhizobacterium Bacillus licheniformis. In the greenhouse experiment, plant length, leaf area index and shoots dry matter were evaluated periodically for the Brassicaceae examined. Whereas plant length, grains production, weight of 1,000 seeds, ear fertility and tiller density were determined under field conditions at the end of the crop cycle for wheat and barley. In general, the species tested appeared to be tolerant to high heavy metal concentrations in soil, and slightly significant differences were found for all parameters considered. A marked growth increase was shown to occur for Brassicaceae cultivated on compost- and bacillus-amended contaminated soils, with respect to non-amended contaminated soils. With some exception, higher growth parameters were measured for wheat and barley plants cropped from contaminated soils in comparison to non-contaminated soils. Further, bacillus amendment enhanced the length of wheat and barley plants in both non-contaminated and contaminated soils, while different effects were observed for the other parameters evaluated.

INTRODUCTION: Thermal power plants emit various gaseous and particulate pollutants into the atmosphere. It is well known that trees help to reduce air pollution. Development of a greenbelt with suitable plant species around the source of emission will mitigate the air pollution. Selection of suitable plant species for a greenbelt is very important. MATERIALS AND METHODS: Present study evaluates different plant species around Neyveli thermal power plant by calculating the Air Pollution Tolerance Index (APTI) which is based on their significant biochemical parameters. Also Anticipated Performance Index (API) was calculated for these plant species by combining APTI values with other socio-economic and biological parameters. DISCUSSION: Based on these indices, the most appropriate plant species were identified for the development of a greenbelt around the thermal power plant to mitigate air pollution. Among the 30 different plant species evaluated, Mangifere indica L. was identified as keystone species which is coming under the excellent category. CONCLUSION: Ambient air quality parameters were correlated with the biochemical characteristics of plant leaves and significant changes were observed in the plants biochemical characteristics due to the air pollution stress.

INTRODUCTION: We conducted a yearly polluted-reference sampling to assess the effects of petroleum pollution on life cycle characteristics of the meiobenthic nematode Odontophora villoti. Samples were taken every 15 days between 26 November 2004 and 25 November 2005 from two beaches of Bizerte bay (Tunisia), Rimel and Tunisian Refining Industries Company (TRIC). The latter site is located in front of the “Tunisian Refining Industries Company” runoff. DISCUSSION: When compared to the reference site, the mean body dimensions of O. villoti from the impacted site were significantly lower. The small size of affected nematodes was represented both by the length and width as a function of the life stage. It was also established that changes in lengths of body parts during molts were different between the two study sites. The low availability of oxygen from April to August seems to prevent the formation of embryos of O. villoti. Thus, two annual reproductive cycles with different durations were observed in Rimel and TRIC. Under stress, juvenile phase and egg production were generally shorter. Globally, the impact of petroleum pollution on O. villoti was expressed by a short egg-to-egg development time. CONCLUSION: Our study assessed the usefulness of life cycle characteristics (biometry and life stage durations) of O. villoti in biomonitoring, and the results are generally consistent suggesting that this species may be considered as an efficient bioindicator.

INTRODUCTION: Ethylenediamine-grafted multiwalled carbon nanotubes (MWCNTs-EDA-I and MWCNTs-EDA-II) are optimized and employed to investigate the preconcentration of lead ions (Pb(II)) in trace level. RESULTS: The results show that Pb(II) can be adsorbed quantitatively on the optimized MWCNTs in the range of pH 4–7 and MWCNTs-EDA-I has a higher maximum Pb(II) adsorption capacity (157.19 mg/g) than MWCNTs-EDA-II (89.16 mg/g). The adsorbed Pb(II) can be eluted completely using 5 mL of 1 mol/L HNO3. DISCUSSION: A new approach using a microcolumn packed with the obtained MWCNTs-EDA-I has been developed for the preconcentration of trace amount of Pb(II). Parameters influencing the preconcentration of Pb(II), such as pH of the sample, sample volume, elution solution, and interfering ions, have been examined and optimized in detail. Under optimum experimental conditions, the limit of detection is 0.30 ng/mL with the enrichment factor of 60. The relative standard deviation (R.S.D) was 2.6% at the 20 ng/mL Pb(II) level. CONCLUSION: The method has been applied for the preconcentration of trace amount of Pb(II) in environmental water samples with satisfying results.

PURPOSE: This study assessed the concentrations of platinum (Pt) and palladium (Pd) in surface sediments and sedimentary cores collected from the Pearl River Estuary with a view of evaluating the distribution, background levels, possible sources, and contamination level of anthropogenic Pt and Pd. MATERIALS AND METHODS: Thirty-six samples of surface sediments and 12 samples from sedimentary cores were collected. Al2O3 was analyzed on fused glass disks by X-ray fluorescence spectrometer. Heavy metal elements were measured by inductively coupled plasma–mass spectrometry. Pt and Pd were separated from the sample matrix by anion exchange chromatography and subsequent solvent extraction after samples had been digested in Carius tubes using aqua regia. The analysis of Pt and Pd was performed by isotopic dilution-inductively coupled plasma-mass spectrometry. RESULTS AND DISCUSSION: Pt and Pd concentrations in surface sediments were 0.28–2.11 and 0.39–38.30 ng/g, respectively, and Pt and Pd concentrations in sedimentary cores were 0.19–1.18 and 0.15–1.76 ng/g, respectively. Background values of Pt and Pd were 0.20–1.17 and 0.10–1.34 ng/g, respectively. The spatial distribution of the enrichment factor differed between Pt and Pd in surface sediments. Down-core variations in Pt, Pd, and other heavy metal elements were similar in all cases and were related to sediment type. CONCLUSIONS: Some of the Pt and Pt in surface samples were derived from anthropogenic emissions. Pt and Pd were delivered to the sediment by fluvial input. In addition to vehicle exhaust catalysts, Pt and Pd were derived from other sources (e.g., industrial process). An important post-burial remobilization process of Pt and Pd is likely to be particle mixing by billows caused by typhoon.

PURPOSE: The purpose of this study is the development of a suitable process for the disinfection of drinking water by evaluating bactericidal efficacy of silver ions from silver electrodes. METHODS: A prototype of a silver ioniser with silver electrodes and control unit has been fabricated. Silver ions from silver electrodes in water samples were estimated with an atomic absorption spectrophotometer. A fresh culture of Escherichia coli (1.75 × 103 c.f.u./ml) was exposed to 1, 2, 5, 10 and 20 ppb of silver ions in 100 ml of autoclaved tap water for 60 min. The effect of different pH and temperatures on bactericidal efficacy was observed at constant silver ion concentration (5 ppb) and contact time of 30 min. RESULTS: The maximum bactericidal activity (100%) was observed at 20 ppb of silver ion concentration indicating total disinfection after 20 min while minimum bactericidal activity (25%) was observed after 10 min at 01 ppb of silver ions. Likewise, 100% bactericidal activity was noticed with 2, 5 and 10 ppb of silver ions after 60, 50 and 40 min, respectively. Bactericidal activity at pH 5, 6, 7, 8 and 9 was observed at 79.9%, 79.8%, 80.5%, 100% and 100%, respectively, whereas it was 80.4%, 88.3%, 100%, 100% and 100% at 10°C, 20°C, 30°C, 40°C and 50°C, respectively. CONCLUSION: The findings of this study revealed that very low concentrations of silver ions at pH 8–9 and temperature >20°C have bactericidal efficacy for total disinfection of drinking water. Silver ionisation is suitable for water disinfection and an appropriate alternative to chlorination which forms carcinogenic disinfection by-products.

INTRODUCTION: Members of the genus Sphingomonas have raised increasing attention due to their ability for polycyclic aromatic hydrocarbon (PAH) degradation and their ubiquity in the environment. However, few studies have revealed the ecological information on the abundance and diversity of Sphingomonas in the environment. MATERIALS AND METHODS: A primer set targeting the Sphingomonas 16S rRNA gene was designed. The specificity was tested with four petroleum-contaminated soils by construction of clone libraries and further restriction fragment length polymorphism analysis. Subsequently, real time PCR and denaturing gradient gel electrophoresis (DGGE) assays were used to evaluate the abundance and diversity of Sphingomonas in the Shenfu irrigation zone, China. RESULTS: A genus-specific primer set SA/429f-933r was developed, and 90% of the sequences retrieved from soil clone libraries were related to Sphingomonas. Members of the genus Sphingomonas were detected in all soils, and significant correlation (p < 0.05) was observed between the Sphingomonas abundance and the ratios of PAHs to total petroleum hydrocarbon (TPH). DGGE profiles revealed Sphingomonas population structures differed greatly in different sites. The Sphingomonas diversity was not statistically (p > 0.05) correlated with the contamination level. Some of the soil-derived sequences were not grouped phylogenetically with sequences of known Sphingomonas, indicating new members of the Sphingomonas genus might be present in the Shenfu irrigation zone. CONCLUSION: The newly designed Sphingomonas-selective primers were specific and practicable for analyzing Sphingomonas abundance and diversity in petroleum-contaminated soils. The significant correlation between the abundance and the ratios of PAHs to TPH suggested an important role of Sphingomonas in PAH bioremediation.