Enhanced remediation of dioxins-spiked soil by a plant-microbe system using a dibenzofuran-degrading Comamonas sp. and Trifolium repens L

In this study, rhizoremediation technology was applied to dioxins-spiked soil. A dibenzofuran-degrading bacterium Comamonas sp. strain KD7, reported in the previous paper, was used in combination with white clover (Trifolium repens L.). First, the effect of strain KD7 on clover seed germination and root elongation was examined in the presence of dioxins compounds. As a result, the white clover seeds inoculated with strain KD7 exhibited a higher germination efficiency and increased root elongation compared with uninoculated white clover. Next, the recovery efficiency of two extraction methods were considered for analyzing the dioxin concentration in soil samples, then, the potential of the plant-microbe combination was evaluated for the remediation of dioxins-spiked soil. After 12 week of growth, significant reductions in the soil were confirmed for most compounds. Our results demonstrated that clover can function as a carrier in order to increase the dioxin-degrading activity of strain KD7. The association of clover and strain KD7 is considered to be a potential tool in the remediation of dioxin-contaminated soil.     

Organic acids and aldehydes in throughfall and dew in a Japanese pine forest

We analyzed low molecular weight organic acids and aldehydes in throughfall under pine forest, and organic acids in dew on chemically inert surfaces and pine needle surfaces at urban- and mountain-facing sites of pine forest in western Japan. Low molecular weight organic acids and aldehydes accounted for less than 5% of the dissolved organic carbon in throughfall at both sites. Formaldehyde at both sites and formate at the mountain-facing site were found at significantly lower concentrations in throughfall than in rainfall, which may be explained by the degradation and/or retention of these components by the pine canopy as the incident precipitation passed through it. The oxalate concentration in throughfall was significantly higher than those in rainfall at both sites, suggesting that oxalate was derived from leaching from the pine foliage. At both sites, organic acid concentrations were higher in dew on the pine needles than in throughfall or dew on chemically inert surfaces. This could be due to the long contact time of dew on pine needles, during which leached substances from pine needles and dry deposits accumulated on their surfaces can dissolve into the small volume of dew. The role of enhanced concentrations of oxalate in an aqueous phase on the plant surfaces (e.g., dew) is discussed in relation to hydroxyl radical formation via the photo-Fenton reaction.     

The relationship between seasonal variations of total-nitrogen and total-phosphorus in rainfall and air mass advection paths in Matsue,Japan

We collected rainwater samples from every rainfall in Matsue, Japan in order to study variations of nitrogen and phosphorus concentrations over time. The seasonal average concentration by magnitude order of Total Nitrogen (here after T-N) was highest in winter, then in spring, fall, and summer and that of Total Phosphorus (here after T-P) was highest in spring, then in winter, fall, and summer. These seasonal variations were examined in relation to the transportation paths of arrived air masses by using a backward trajectory and rainfall patterns from a surface synoptic weather chart. In winter, continental air masses frequently flow from China or Siberia and the resultant winter rainfall is on many occasions of a continental type. In summer, maritime air masses frequently arrive from the Pacific Ocean and this resultant rainfall therefore was often of maritime type. Looking at average concentrations of T-N and T-P for each rainfall type, continental types were high range and maritime types were low. It was therefore concluded that the monthly average concentration of T-N was affected by continental air masses from northern China in winter and by maritime ones from the Pacific Ocean in summer. The maximum deposition of T-N was caused by this concentration in winter and rainfall depth in summer. Seasonal variation of T-P showed a different fluctuation tendency from T-N, with a maximum concentration in spring, and minimum in summer and fall. T-P was susceptible to the yellow sand phenomenon which maximised T-P deposition in spring.     

Dry and wet deposition of water-insoluble dust and water-soluble chemical species during spring 2007 in Tsukuba,Japan

Dry and wet depositions were sampled daily in Tsukuba, Japan, in spring 2007. Temporal variations in the dry and wet deposition fluxes of dust and water-soluble chemical species were controlled largely by air mass origin, the water vapor mixing ratio, and Asian dust events. The contribution of local sources to dry deposition of dust was large when the wind speed was high. Dry deposition fluxes of water-soluble chemical species were larger in humid air masses than in dry air masses. Wet deposition fluxes of dust and water-soluble chemical species indicated that air masses that passed over dust source regions and industrial regions became mixed with the maritime air masses over the coastal site of the Asian continent and western part of the Japanese islands. The total deposition of dust was 4220 mg m^?2 month^?1, and that of water-soluble chemical species ranged from 10 to 636 mg m^?2 month^?1. Wet deposition fluxes of the total deposition flux of dust accounted for 72% and those of water-soluble chemical species was for 72–96%. In particular, the largest wet deposition occurred during a single Asian dust event on 3 April. This event accounted for 23% (950 mg m^?2 month^?1) of the monthly dust deposition flux and for 2–28% (0.43–51 mg m^?2 month^?1) of the monthly deposition flux of water-soluble chemical species. This result implies that the wet deposition flux associated with even one sporadic Asian dust event can have extensive impacts on both terrestrial and oceanic ecosystems in East Asia.     

Waste on the roadside, 'poi-sute' waste: its distribution and elution potential of pollutants into environment

Waste on the roadside, 'poi-sute' waste, was collected in a typical suburb in Japan (Ueda city, the sampling course: 3.2 km). The distribution, characterization of the 'poi-sute' waste and the loading of pollutants from the waste were studied. The average number of pieces of total waste was 690 pieces a month, and 220 pieces of waste were dumped a month per km. There was a tendency for much waste to be discarded around shops staying open until late at night. Regarding the sorts of the waste, cigarette butts are the most prevalent (the average was 150 cigarette butts/km/mo), and second was plastic materials. As for the weight, cigarette butts, plastics and papers were at a similar level (about 90 g/km/mo). The elution of arsenic (0.041 mg/L) and nicotine (3.8 mg/L) was ascertained by a dissolution test of 'poi-sute' cigarette butts obtained by sampling. Furthermore, the loading of heavy metals, such as lead, copper, chromium and cadmium, and polycyclic aromatic hydrocarbons (PAHs) from cigarette butts into the environment was confirmed. The load potentials of heavy metals were 0.020-1.7 mg/km/mo, and that of total-polyaromatic hydrocarbons was 0.032 mg/km/mo. These results indicate that the 'poi-sute' waste has a harmful influence on the environment.     

A sex pheromone component novel to Ostrinia identified from Ostrinia latipennis (Lepidoptera: Crambidae)

Summary. Extracts from the sex pheromone gland of Ostrinia latipennis (Lepidoptera: Crambidae) were analyzed by gas chromatography-electroantennographic detection (GC-EAD) and GC-mass spectrometry. Only an EAD-active compound was detected in the extract, and it was identified as (E)-11-tetradecenol (E11-14:OH). In a wind-tunnel bioassay, E11-14:OH elicited a series of mate finding behaviors from males, although it was far less active than virgin females and crude extract of the pheromone gland. The attractiveness of E11-14:OH to O. latipennis males was confirmed by field trapping experiments. Based on these findings, we concluded that E11-14:OH, which is novel to the genus Ostrinia, is a major component of the sex pheromone in O. latipennis. The significance of the use of alcohol in place of the usual acetates in Ostrinia is discussed in relation to the pheromone biosynthesis system. Received 9 December 1999; accepted 14 March 2000     

Dioxins in human milk and smoking of mothers

BACKGROUND: The relation between the levels of dioxins in human breast milk and the smoking habits of the mothers is controversial. To clarify this relationship, we analyzed data from the human milk survey in Japan. METHODS: The human milk survey has been conducted in Japan since 1997. Healthy pregnant women aged 20-39 years were recruited and 50 ml of breast milk was collected from them at 30 days after delivery. PCDDs, PCDFs, and dioxin-like PCBs were measured by using GC/MS. The smoking habits of the mothers were established by interviewing them soon after delivery and were classified into four categories: current smokers, ever smokers who quit smoking at the pregnancy, ever smokers who quit smoking before the pregnancy, and never smokers. The levels of dioxins in breast milk were compared in the four categories of smoking among 853 primiparas. In addition, we analyzed the association between dioxin levels and passive smoking among never smokers. The geometric means of the dioxin concentrations were calculated in order to compare the differences between dioxins. RESULTS: The geometric means of dioxin-like PCBs in milk of never smokers was the highest (9.2 pg TEQ/g fat); followed by ever smokers who quit smoking before the pregnancy, ever smokers who quit smoking at the pregnancy, and current smokers (7.5, 7.2, and 6.6 pg TEQ/g fat, respectively). The differences between these levels were statistically significant (ANOVA, p<0.001). No significant difference was observed between the level of dioxins in milk from never smokers subjected to passive smoking status and those who had not experienced passive smoking. CONCLUSION: The levels of dioxin-like PCBs in human milk were negatively related to the smoking habits of mothers.     

Concentrations of organochlorine pollutants in mothers who gave birth to neonates with congenital hypothyroidism

We have investigated the effects of prenatal exposure to dioxin-like compounds (PCDDs, PCDFs and dioxin-like PCBs), PCBs and organochlorine pesticides (DDT, HCH, chlordane, HCB and their metabolites) on the incidence of congenital hypothyroidism and/or cretinism in Fukuoka, Japan from 2001 to 2004. Thirty-four positive neonates of the mass-screening for cretinism were classified into three groups by the pediatrician after the reevaluation of the serum TSH level, that is, negative in reevaluation group, hyper thyroid stimulating hormone (TSH) emia group and cretinism group. One-hundred and two negative neonates of the mass-screening were classified into the normal group. Concentrations of these organochlorine compounds in the breast milk of mothers, which were considered as the indicator of prenatal exposures to them, were gradually increased from the normal group to the cretinism group in the four groups and were around two times higher in the cretinism group than in the normal group. According to the case-control study adjusted for the parity and mother's age, odds ratios of PCBs, DDT and HCB were 10 (p=0.003), 10 (p=0.003) and 22 (p=0.004), respectively and in dioxin-like compounds, PCDFs showed the highest odds ratio, 9.8 (p=0.005). Based upon those findings, these compounds seemed play an important role in the incidence and/or causation of the cretinism.