Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157:H7. This study investigated pathogenic bacteria in compost collected from the compost facilities, an

IntroductionIncreasing public interests have been concerned onsafety foods and the environmental aspects recently,especially on the so-called organic foods , which are madefromcrops grown with organic fertilizers or compost but notchemical fertilizers .Pu…     

Removal of Linear and Branched p-Alkylphenols from Aqueous Solution by Combined Use of melB Tyrosinase and Chitosan Beads

In this study, melB tyrosinase was applied for enzymatic removal of linear and branched p-alkylphenols from aqueous solutions. First, systematic studies were carried out to estimate the effects of the process parameters such as the temperature, pH value, and enzyme dose on quinone conversion of p-cresol as a model phenol compound. A variety of p-alkylphenols were removed from aqueous solutions through the tyrosinase-catalyzed quinone conversion and subsequent nonenzymatic adsorption of quinone derivatives on chitosan beads at pH 6.0 and 30 °C under the optimum conditions determined for p-cresol. The % removal values of 98–100 were obtained for p-n-alkylphenols. Branched p-alkylphenols with a weak estrogenic activity containing 4-tert-butylphenol and 4-tert-pentylphenol, which underwent no quinone conversion by commercially available mushroom tyrosinase in the absence of H₂O₂, were also effectively removed by further increasing either the melB tyrosinase concentration or the amount of added chitosan beads. The present technique is much effective in the fact that a series of reactions rapidly progress under mild conditions and the chitosan beads can be readily separated from the reaction medium after the enzymatic treatment.     

Potential bioremediation of mercury-contaminated substrate using filamentous fungi isolated from forest soil

The use of filamentous fungi in bioremediation of heavy metal contamination has been developed recently. This research aims to observe the capability of filamentous fungi isolated from forest soil for bioremediation of mercury contamination in a substrate. Six fungal strains were selected based on their capability to grow in 25 mg/L Hg2+-contaminated potato dextrose agar plates. Fungal strain KRP1 showed the highest ratio of growth diameter, 0.831, thus was chosen for further observation.Identification based on colony and cell morphology carried out by 18S rRNA analysis gave a 98%match to Aspergillus flavus strain KRP1. The fungal characteristics in mercury(Ⅱ) contamination such as range of optimum pH, optimum temperature and tolerance level were 5.5–7 and 25–35℃ and 100 mg/L respectively. The concentration of mercury in the media affected fungal growth during lag phases. The capability of the fungal strain to remove the mercury(Ⅱ) contaminant was evaluated in 100 mL sterile 10 mg/L Hg2+-contaminated potato dextrose broth media in 250 mL Erlenmeyer flasks inoculated with 108spore/mL fungal spore suspension and incubation at 30℃ for 7 days. The mercury(Ⅱ) utilization was observed for flasks shaken in a 130 r/min orbital shaker(shaken) and nonshaken flasks(static) treatments. Flasks containing contaminated media with no fungal spores were also provided as control. All treatments were done in triplicate. The strain was able to remove 97.50%and 98.73% mercury from shaken and static systems respectively. A. flavus strain KRP1 seems to have potential use in bioremediation of aqueous substrates containing mercury(Ⅱ) through a biosorption mechanism.     

Adsorption and desorption characteristics of several herbicides on sediment

The objective of this study was to clarify the adsorption and desorption characteristics of several herbicides in sediment. Five herbicides, esprocarb, thiobencarb, dimethametryn, pretilachlor, and simetryn were examined in this study. The adsorption ratio on the sediment increased in the following order: pretilachlor < dimethametryn < simetryn < thiobencarb < esprocarb. On the other hand, the adsorption ratio on the sediment without organic matter increased in the following order: thiobencarb < esprocarb < pretilachlor < dimethametryn < simetryn. Furthermore, the amounts of simetryn, dimethametryn, and pretilachlor adsorbed on the sediment without organic matter increased, while those of esprocarb and thiobencarb decreased in comparison to the original sediment. These results strongly suggested that the mineral surface in the sediment was very important as the adsorption site for the herbicide, especially in the case of simetryn, dimethametryn, and pretilachlor. All the adsorption and desorption data fitted well with the Freundlich equation. The hysteresis in the adsorption-desorption phenomena in the sediment was observed for all the herbicides, and it was affected by the organic matter in sediment, especially in the case of dimethametryn and pretilachlor.     

Detection of dicofol and related pesticides in human breast milk from China, Korea and Japan

Previously, we demonstrated that the concentrations of DDTs were greater in breast milk collected from Chinese mothers than from Japanese and Korean mothers. To investigate dicofol as a possible source of the DDTs in human breast milk, we collected breast milk samples from 2007 to 2009 in China (Beijing), Korea (Seoul, Busan) and Japan (Sendai, Takarazuka and Takayama). Using these breast milk samples, we quantified the concentrations of dichlorobenzophenone, a pyrolysis product of dicofol (simply referred to as dicofol hereafter), dichlorodiphenyltrichloroethane and its metabolites (DDTs) using GC-MS. Overall, 12 of 14 pooled breast milk samples from 210 mothers contained detectable levels of dicofol (>0.1 ng g⁻¹ lipid). The geometric mean concentration of dicofol in the Japanese breast milk samples was 0.3 ng g⁻¹ lipid and significantly lower than that in Chinese (9.6 ng g⁻¹ lipid) or Korean breast milk samples (1.9 ng g⁻¹ lipid) (p < 0.05 for each). Furthermore, the ΣDDT levels in breast milk from China were 10-fold higher than those from Korea and Japan. The present results strongly suggest the presence of extensive emission sources of both dicofol and DDTs in China. However, exposure to dicofol cannot explain the large exposure of Chinese mothers to DDTs because of the trace levels of dicofol in the ΣDDTs. In the present study, dicofol was confirmed to be detectable in human breast milk. This is the first report to identify dicofol in human samples.     

Quantitative analysis of perfluorinated chemicals in media for in vitro fertilization and related samples

The actual standard in vitro fertilization (IVF) protocol recommends an overnight gamete co-incubation. All of the culture media used for human IVF are supplemented with serum or albumin. In the present study, we determined the concentrations of perfluorinated chemicals (PFCs) in IVF media (IVFM) and related samples by liquid chromatography with tandem mass spectrometry (LC/MS/MS). The results indicated that the concentrations of PFOS and PFOA in the protein source were higher than those in the IVFM samples. Compared with human plasma concentrations of PFCs, PFCs in all of the IVFM samples, such as PFBS, PFHxS and PFOA, were either not detected or present at only trace levels, even when protein source was added. LC/MS/MS could be used to determine PFCs in IVFM samples in future studies of the effects of PFC exposure on intrauterine insemination.     

CIELAB color variables as indicators of compost stability

The composting process of different organic wastes both in laboratory and on a large-scale was characterized using CIELAB color variables to evaluate compost stability for the better application in agriculture. The time courses of the CIELAB variables of composting materials were determined directly from the bottom of a glass petri dish filled with dried and ground samples using a Minolta Color Reader (CR-13) calibrated with clean empty petri dishes placed on a white tile. To compare the proposed method with conventional methods, the same materials were also evaluated using commonly used compost stability evaluation indices. Most of the CIELAB variables of a compost made from a mixture of green tea waste and rice bran reached a plateau after 84 days of composting and showed strong relationships with the commonly used compost stability evaluation indices. The time needed for CIELAB variables, especially the L*and b* values, to stabilize at large-scale composting plants of cattle litter, farmyard manure, kitchen garbage and bark compost, were more or less similar to the times of maturation evaluated by the respective compost producers. The CIELAB color variable offers a new, simple, rapid and inexpensive means of evaluating compost stability and its quality prior to agricultural use.     

Postcopulatory mate guarding by vocalization in the Formosan squirrel

The Formosan squirrel, Callosciurus erythraeus thaiwanensis, emitted different vocalizations in response to terrestrial and aerial predators and snakes. Each vocalization caused nearby individuals to adopt a different type of anti-predator behaviour. In mating bouts, males produced two types of loud calls: precopulatory calls, emitted before copulations, and postcopulatory calls, emitted after copulations. The latter continued for 17 min on average. The estrous female and other males attending the mating bouts stopped moving during the postcopulatory call, so that the calling male was able to tend the female without interruption. The sound characteristics of anti-terrestrial-predator and postcopulatory calls recorded in the captivity were compared, and none of the ten characters of duration and frequency measured differed between the two calls. Playback experiments also showed that responses to the sounds in two different contexts, escape behaviour and defensive immobility, did not differ. The similarity between anti-predator and postcopulatory calls is discussed with reference to the possibility of manipulation and other explanatory hypotheses.     

Separation of plastic mixtures using liquid-fluidized bed technology

Separation of heavier-than-water plastic mixtures had been investigated via the fluidization of their packed beds induced by an upward flow of water. The samples examined were resin pellets and crushed plastic products including PVC, PET and PBT. On the onset of a flow, a mixed bed was swelled to the state of fluidization and separated into layers of respective resins depending on their density. The effects of the flow rate, an amount of the samples and their density difference were examined on the separation of resin pellets. Under an appropriate condition, the process was completed within a few minutes, and satisfactory separation was attained when the density difference of the samples exceeded 0.05 g cm-3. By using a column equipped with several sample outlets sorted resins could be recovered with their purity intact by withdrawing each layer successively from above through a suitable outlet. Multi-stage separation was also found to be effective in treating close-density samples. Compared with uniform-sized resin pellets, size distribution of crushed plastic samples deteriorated the separation to some extent.