A fate model of pathogenic viruses in a composting toilet based on coliphage inactivation

A composting toilet using sawdust as a matrix has the potential to trap pathogens that might occasionally be contained in human feces. Therefore, care should be taken when handling the sawdust. It should also be noted that pathogenic viruses tend to have stronger tolerance than pathogenic bacteria. The fates of several species of coliphages, T4, , Q and MS2, in sawdust were investigated as a viral model. The fates of coliphages were significantly different among them, and they changed in response to temperature and the water content of the sawdust. As the results, T4 coliphage had the strongest tolerance and Q had the weakest one in sawdust. It was estimated the days required to decrease virus to a safe level based on a risk assessment. According to the rates of Q and T4, 15 days and 167 days were required respectively for a safe level of infection risk based on actually operated composting toilet condition. Thus, it was significantly different depending on the species and sawdust conditions.     

Lipid storage and composition in tropical surgeonfishes (Teleostei: Acanthuridae)

The lipid composition of tropical marine reef fishes is poorly known, despite their use as food by local human populations and recent interest in health-related benefits of fish lipids. We examined the composition of lipids from epaxial muscle, liver, and two storage sites [mesenteries surrounding the gut (intraperitoneal fat, IPFs) and retroperitoneal fat bodies (FBs) posterior to the peritoneal cavity] in three species of surgeonfishes from Ishigaki Island, Japan: Naso lituratus (Bloch and Schneider, 1801), Acanthurus lineatus (Linnaeus, 1758), and A. bariene (Lesson, 1830). Triacylglycerols dominated all samples of neutral lipid and constituted ≥ 99% of FBs and IPFs. Polar lipids generally contained large fractions of phosphatidylethanolamine and phosphatidylcholine. Quantified fatty acids ranged in length from C₁₄ to C₂₄. C₁₆ fatty acids prevailed (>35% of neutral fatty acids, >23% of polar fatty acids), although C₁₈ (>16 and >14%, respectively) and C₂₀ acids (>8 and >19%, respectively) were also common. Saturated fatty acids, dominated by palmitic acid (16:0), comprised 38.7 to 50.7% of acids from neutral lipids and 30.8 to 41.1% from polar lipids. The most common monounsaturated acids were 18:1n9 and 20:1n9. Polyunsaturated acids were prevalent in polar lipids (especially 20:4n6, 20:5n3, 22:2n3, 22:5n3, 22:5n6 and 22:6n3). Common polyunsaturated acids of neutral lipids were 18:2n6, 18:4n3, several n-3 and n-6 C₂₀ acids, 22:2n3 and 22:5n3. IPF and FB were almost identical across species, and lipids of fat bodies (IPFs, FBs) were more similar to those of muscle than those of liver for all three species. The FBs appear to constitute an accessory storage site, which overcomes constraints on lipid storage imposed by a small, inflexible abdominal cavity that contains both viscera and consistently voluminous gut contents. Fatty acid signatures indicate that largely overlooked epiphytic or epilithic diatoms contribute significantly to lipid acquisition. The combination of large quantities of both saturated and n-3 and other polyunsaturated fatty acids in surgeonfishes, in contrast to low saturates and high polyunsaturated acids in lipids of commercially important cool-water fishes, suggests that a study of dietary effects of fish lipids on human inhabitants of the tropics may be instructive insofar as human health and nutrition are concerned. Received: 16 March 1998 / Accepted: 6 August 1998     

Occurrence of tributyltin (TBT)-resistant bacteria is not related to TBT pollution in Mekong River and coastal sediment: with a hypothesis of selective pressure from suspended solid

Tributyltin (TBT) is organotin compound that is toxic to aquatic life ranging from bacteria to mammals. This study examined the concentration of TBT in sediment from and near the Mekong River and the distribution of TBT-resistant bacteria. TBT concentrations ranged from <2.4 to 2.4 ng/g (dry wt) in river sediment and <2.4-15 ng g(-1) (dry wt) in harbor sediment. Viable count of total bacteria ranged from 2.0 x 10(4) to 1.4 x 10(7)cfu/g, and counts of TBT-resistant bacteria ranged <1.0 x 10(2) to 2.5 x 10(4)cfu/g. The estimated occurrence rate of TBT-resistant bacteria ranged from <0.01 to 34% and was highest in upstream sites in Cambodia. The occurrences of TBT in the sediment and of TBT-resistant bacteria were unrelated, and chemicals other than TBT might induce TBT resistance. TBT-resistant bacteria were more abundant in the dry season than in the rainy season. Differences in the selection process of TBT-resistant bacteria between dry and rainy seasons were examined using an advection-diffusion model of a suspended solid (SS) that conveys chemicals. The estimated dilution-diffusion time over a distance of 120 km downstream from a release site was 20 days during dry season and 5 days during rainy season, suggesting that bacteria at the sediment surface could be exposed to SS for longer periods during dry season.     

Heart rate changes reveal that little blue penguin chicks (Eudyptula minor) can use vocal signatures to discriminate familiar from unfamiliar chicks

Researchers investigating social recognition typically measure only behavioural responses during discrimination tests - physiological changes have been largely ignored. We examined whether little blue penguin chicks (Eudyptula minor) could distinguish siblings from other chicks using auditory cues, by measuring behavioural and heart rate changes during playback experiments. Chicks were exposed to five treatments: the begging calls of siblings, neighbouring chicks and unfamiliar chicks, and two controls (heterospecific begging calls and music). We also determined if chicks developed distinctive begging calls, by using F-ratios to quantify inter- versus intra-individual variability in a range of acoustic parameters, and applying a discriminant-function analysis. Inter-individual variation was greater for pitch than for temporal or amplitude parameters, suggesting that call pitch may be important for individual recognition. The discriminant-function analysis showed each chick's calls were distinctive and could act as a vocal signature. Treatments did not instigate different behavioural responses. However, chick heart rates during playback of sibling calls were significantly higher than those recorded during stranger, but not neighbour, playback. A simple recognition system based on familiarity may allow this plesiomorphic and loosely colonial penguin to gain at least some of the benefits associated with more advanced sibling recognition systems (some highly colonial seabirds discriminate siblings from neighbouring chicks). Heart rate could be a useful measure of social recognition abilities, particularly in species where changes in behaviour are not always evident or are difficult to observe.     

Soil heterogeneity effects on acid flushing of lead-contaminated soil

A compact model for evaluation of acid flushing of heavy-metal-contaminated soil in a small-scale on-site treatment plant is proposed. The model assumes that the soil was re-packed in a container after excavation resulting in a soil structure with heterogeneous and random physical and chemical properties. To evaluate the effects of heterogeneity on the efficiency of contaminant removal by acid flushing, a numerical analysis of lead transport in the heterogeneous soil medium was performed. The model examines cation exchange and surface complexation reactions involving three cations (Ca, Pb, and H) and one anion (Cl) in both dissolved and exchangeable forms, two Pb surface complexes (SOPbCl and SOPbOH), and one Cl surface complex (SOH₂Cl). The transport of these species during flushing with acid in a synthetically generated two-dimensional heterogeneous soil was simulated in the model. Results indicated that the flushing fluid preferentially followed pathways with large permeability. The heterogeneous cation exchange capacity (CEC) distribution and surface complexation sites had a significant effect on the transport of dissolved species. Because the CEC was set to a relatively low value, Pb was adsorbed mainly as surface complexes (SOPbCl and SOPbOH). Simulation results suggest that blocks of low hydraulic conductivity located in the upper part of the model domain greatly impede solute transport. Ponding conditions did not significantly affect the efficiency of decontamination. The model and its results are useful in the design of small-scale treatment plants for acid flushing.     

Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography–tandem mass spectrometry

A sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid–liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC–MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC–MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005–0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.     

Sensitivity analyses of factors influencing CMAQ performance for fine particulate nitrate

Improvement of air quality models is required so that they can be utilized to design effective control strategies for fine particulate matter (PM_2.5). The Community Multiscale Air Quality modeling system was applied to the Greater Tokyo Area of Japan in winter 2010 and summer 2011. The model results were compared with observed concentrations of PM_2.5 sulfate (SO₄^2-), nitrate (NO₃^?) and ammonium, and gaseous nitric acid (HNO₃) and ammonia (NH₃). The model approximately reproduced PM_2.5 SO₄^2? concentration, but clearly overestimated PM_2.5 NO₃^? concentration, which was attributed to overestimation of production of ammonium nitrate (NH₄NO₃). This study conducted sensitivity analyses of factors associated with the model performance for PM_2.5 NO₃^? concentration, including temperature and relative humidity, emission of nitrogen oxides, seasonal variation of NH₃ emission, HNO₃ and NH₃ dry deposition velocities, and heterogeneous reaction probability of dinitrogen pentoxide. Change in NH₃ emission directly affected NH₃ concentration, and substantially affected NH₄NO₃ concentration. Higher dry deposition velocities of HNO₃ and NH₃ led to substantial reductions of concentrations of the gaseous species and NH₄NO₃. Because uncertainties in NH₃ emission and dry deposition processes are probably large, these processes may be key factors for improvement of the model performance for PM_2.5 NO₃^?.

Implications: The Community Multiscale Air Quality modeling system clearly overestimated the concentration of fine particulate nitrate in the Greater Tokyo Area of Japan, which was attributed to overestimation of production of ammonium nitrate. Sensitivity analyses were conducted for factors associated with the model performance for nitrate. Ammonia emission and dry deposition of nitric acid and ammonia may be key factors for improvement of the model performance.     

Residual congener pattern of dioxins in human breast milk in southern Vietnam

This study evaluated residual congener patterns of dioxin/furan (=PCDD/DF) related to tactical herbicides aerially sprayed over the regions of southern Vietnam through Operation Ranch Hand. The study focused on Cam Chinh (CC) commune, Quang Tri province (an area sprayed with tactical herbicides), and the Cam Phuc (CP) commune, Ha Tinh province (a non-sprayed area). Breast milk samples for analysis were collected in September 2002 and July 2003 from lactating primiparous and multiparous mothers born after the war (<31 years old). We found the levels of each congener in the CC commune were higher than in the CP commune, and determined specificity in the PCDD/DF congener pattern in CC commune samples by cluster analysis. The congener pattern is characterized by higher (the hexa-, the hepta-, and the octa-) chlorinated PCDD/DFs; this appears to be the same profile as that presented by pentachlorophenol (PCP), rather than 2,4,5-trichlorophenoxy acid (2,4,5-T) contaminated with 2,3,7,8-TCDD. A GC/MS study in the 1970s detected the chlorophenols 2,4-di and 2,4,6-trichlorophenol in some Agent Orange samples, which contained, like PCP, a wide variety of PCDD/DF congeners. In this context, it may be expected that certain tactical herbicides contaminated with various chlorophenol impurities, have a unique congener pattern when compared with pure 2,4,5-T formulations.