The long-term evolutions and the regional characteristics of atmospheric methane concentrations in Nagoya, 1983-1997

This study provides information on the long-term evolutions of the atmospheric methane (CH4) concentrations in Nagoya City, Japan, which were analyzed by using the continuous monitoring data observed at the eight observatory stations for 1983-1997. The 15-year records of the atmospheric CH4 concentrations were examined by means of a time-series analysis using a fast Fourier transform with a low-pass filter to elucidate the seasonal cycles and the long-term trends. The annual averages of the CH4 concentrations in Nagoya were 1.85 ppmv (parts per million by volume), 1.91 ppmv, and 1.90 ppmv in 1988, 1995 and 1997, respectively. Moreover, the annual average growth rate showed a drastic decrease from 17 ppbv (parts per billion by volume) year(-1) in 1992 to 2 ppbv year(-1) in 1993, and further down to 7 ppbv year(-1) in 1997. Comparison of the atmospheric CH4 records in Nagoya with those in global air of the northern hemisphere observed at Mauna Loa observatory in Hawaii, USA, allows us to estimate the excess concentration of CH4 in the urban atmosphere of Nagoya, which was 0.17 ppmv in 1988 and 0.15 ppmv in 1997. On a local scale, the atmospheric CH4 concentrations in the northern part of Nagoya City increased until 1992 and then gradually decreased from 1993 to 1997, although those in the south-western urban areas constantly increased at the averaged growth rate of 13 ppbv year(-1) for 1988-1997. The variation of the long-term trends of the CH4 concentrations in Nagoya may be ascribed to the emission changes from the CH4 sources due to the human activities such as waste dumping and landfills.     

Contamination of soils and plants by mercury as influenced by the proximity to industries in Alexandria,Egypt

The amounts of total Hg in the soils and the edible parts of seven vegetable plant crops grown in unpolluted and polluted soils were studied.The highly polluted soils contained higher levels of Hg (495 ppb) than those in the unpolluted (35 ppb). The topsoil was highly enriched with Hg than the subsoil as the result of the deposition of Hg particulates produced from the industries.Plants grown in soils near industries contained high levels of Hg up to 362 ppb. The amounts of Hg in the plant species which grown in winter were higher than those grown in summer.     

Shifting balances in U.S. metropolitan and nonmetropolitan area growth

"This paper assesses some of the recent attempts to explain the perceived growth reversal between metropolitan and nonmetropolitan areas in the United States during the 1970s. The paper argues that the reversal in population trends was not a one-time, radical shift in settlement trends, but rather the result of more continuous underlying industrial trends. Indeed, since 1979, population growth has again become faster in metropolitan than nonmetropolitan areas." The paper includes three sections. Regional and area population and industrial earnings growth patterns are first summarized for the 1960s, 1970s, and 1980s. Theories of polarization and polar reversal are then evaluated and found to be inadequate. Finally, a reconstruction of the neoclassical model is proposed.     

A computer technique for predicting smoke movement in tall buildings

An approach to the analysis of stack effect has been developed which allows the prediction of internal air flow quantities and associated pressure differentials for specific buildings prior to construction. An example of the application of this analysis is presented for a hypothetical 75-story office building. Note: The authors presented this paper at a symposium on “The Control of Smoke Movement on Escape Routes in Buildings,” sponsored by the Joint Fire Research Organization and held on April 9 and 10, 1969 in Hertfordshire, England.     

Expansion of the US wildland–urban interface

For at least two decades, expansion of low-density residential development at the wildland–urban interface has been widely recognized as a primary factor influencing the management of US national forests. We estimate the location, extent, and trends in expansion of the wildland–urban interface (WUI) in the continental United States. We mapped the WUI by determining the intersection of housing density classes computed from refined US Census data with a map of wildfire hazards based on broad forest types using definitions of WUI from the Federal Register. Our methods allowed us to provide a more spatially precise estimation of the WUI that better reflects development patterns of interest to forest land managers. We defined three wildfire hazard classes based on vegetation type. “High” severity applies to vegetation types in which stand-replacing fires dominate both historical and recent fire regimes, e.g., lodgepole pine forest. “Low” severity applies where fuels and climate foster mostly low-intensity fires, e.g., aspen-birch forest. “High (historically low or variable)” applies to vegetation types in which fires historically were of low or variable intensity, but recently have often burned at high intensity because of a century of fire exclusion, e.g., southwestern ponderosa pine forest. In 2000, the WUI that includes a 3.2 km community protection zone occupied 465,614 km², and contained over 12.5 million housing units. This is an expansion of over 52% from 1970, and by 2030 the WUI is likely to expand to at least 513,670 km² with the greatest expansion occurring in the intermountain west states. Roughly 89% of the WUI is privately owned land and about 65% of the WUI occurs in high or high (historically low or variable) severity fire regime classes.     

Controlein situ du compactage de remblais sous eau

Bulletin of Engineering Geology and the Environment - La fermeture de l'Escaut oriental constitute le couronnement des travaux du Plan Delta aux Pays-Bas. Le danger de l'érosion et de...     

A preliminary note on the sequential decomposition of pectin by aquatic bacteria

In a eutrophic lake, an inverse relationship was observed between total aerobic heterotrophic bacteria and their pectolytic share which consisted mainly of Flavobacterium-Cytophaga species. When grown in a medium containing pectin and yeast extract as organic compounds pure cultures of the most abundant type of this bacterial group showed a diauxic characteristic of growth. Short time before entering the first lag phase of growth, production of pectolytic enzymes increased until the end of the second log phase of growth. This phenomenon may be due to the mechanism of a catabolic repression and derepression.     

Influences of iron, manganese, and dissolved organic carbon on the hypolimnetic cycling of amended mercury

The biogeochemical cycling of iron, manganese, sulfide, and dissolved organic carbon were investigated to provide information on the transport and removal processes that control the bioavailability of isotopic mercury amended to a lake. Lake profiles showed a similar trend of hypolimnetic enrichment of Fe, Mn, DOC, sulfide, and the lake spike ((202)Hg, purity 90.8%) and ambient of pools of total mercury (HgT) and methylmercury (MeHg). Hypolimnetic enrichment of Fe and Mn indicated that reductive mobilization occurred primarily at the sediment-water interface and that Fe and Mn oxides were abundant within the sediments prior to the onset of anoxia. A strong relationship (r(2)=0.986, n=15, p<0.001) between filterable Fe and Mn indicated that reduction of Fe and Mn hydrous oxides in the sediments is a common in-lake source of Fe(II) and Mn(II) to the hypolimnion and that a consistent Mn:Fe mass ratio of 0.05 exists in the lake. A strong linear relationship of both the filterable [Fe] (r(2)=0.966, n=15, p<0.001) and [Mn] (r(2)=0.964, n=15, p<0.001) to [DOC] indicated a close linkage of the cycles of Fe and Mn to DOC. Persistence of iron oxides in anoxic environments suggested that DOC was being co-precipitated with Fe oxide and released into solution by the reductive dissolution of the oxide. The relationship between ambient and lake spike HgT (r(2)=0.920, n=27, p<0.001) and MeHg (r(2)=0.967, n=23, p<0.001) indicated that similar biogeochemical processes control the temporal and spatial distribution in the water column. The larger fraction of MeHg in the lake spike compared to the ambient pool in the hypolimnion suggests that lake spike may be more available for methylation. A linear relationship of DOC to both filterable ambient HgT (r(2)=0.406, n=27, p<0.001) and lake spike HgT (r(2)=0.314, n=15, p=0.002) suggest a role of organic matter in Hg transport and cycling. However, a weak relationship between the ambient and lake spike pools of MeHg to DOC indicated that other processes have a major role in controlling the abundance and distribution of MeHg. Our results suggest that Fe and Mn play important roles in the transport and cycling of ambient and spike HgT and MeHg in the hypolimnion, in part through processes linked to the formation and dissolution of organic matter-containing Fe and Mn hydrous oxides particles.