摘要:

A series of laboratory experiments were conducted to determine whether the positive correlation observed in the ambient atmosphere between ozone and temperature could, in part, be due to a temperature dependency of the photochemical smog reaction kinetics. The experiments were conducted using the propene/NO2/air system in General Motors Research Laboratories’ dynamic irradiation chamber. Over the range of temperatures investigated, 10°C to 50°C, the maximum observed ozone concentration increased with increasing temperature from 10°C to 40°C. Between 40°C and 50°C there was no further increase in ozone. In contrast, it was observed that the amount of peroxyacetylnitrate formed decreased with increasing temperature. These observations can be attributed to the temperature dependence of the thermal decomposition of peroxyacetylnitrate. At low temperatures, the increased stability of this compound makes it a sink for nitrogen dioxide; conversely, at higher temperatures, peroxyacetylnitrate is too unstable to be an effective sink for nitrogen dioxide.

ISSN:0360-1226    

DOI:10.1080/10934528109374958

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The levels of various metals in plastic food wrappings and toys which are frequently subjected to degradation in sanitary landfills have been determined by atomic absorption spectroscopy and neutron activation analysis. The effect of acidic leaching of metals at various pH levels from the disposable items has also been studied to simulate natural environmental degradation.

ISSN:0360-1226    

DOI:10.1080/10934528109374959

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The input of Cadmium, Zinc, Copper, Lead and Nickel was studied at remote areas in Idaho, Utah, Colorado and Wyoming. Concentrations of metals in dustfall collected over two separate time intervals were compared to those from surface soil at each of the sampling sites. Although significant correlation was found among the various metals in soil, there was no significant relationship noted between levels in dustfall and in corresponding soil samples at the individual locations. A general randomness was observed in heavy metal burdens throughout the sampling network, yet, a significant equivalence existed in deposition rates (μg/m2/day) of total dustfall, Cd, Cu and Pb at the individual sites when compared using a paired t‐test. Likewise, equivalence was found in concentrations of Cd and Pb suggesting that local, rather than regionwide, climatic factors may be responsible for the variation in metal levels in atmospheric fallout.

ISSN:0360-1226    

DOI:10.1080/10934528109374960

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A detailed intralaboratory comparison of the determination of arsenic in complex wastewater samples by hydride generation and graphite furnace atomic absorption techniques has been conducted. Two hydride generation techniques were employed. One consisted of the use of sodium borohydride pellets and argon to sweep the arsine into a hydrogen flame. In the second, arsine was produced from a sodium borohydride solution and swept into an air‐acetylene heated quartz tube. The hydride generation techniques yielded consistent, reliable data for highly complex wastewater matrices only when arsine generation was preceded by a closed acid digestion procedure.

ISSN:0360-1226    

DOI:10.1080/10934528109374961

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Kepone was bioaccumulated from a weak aqueous solution byPrototheca zopfii. The solution containing one ppm Kepone was passed through a fixed bed column contaning the alga immobilized in agar beads. The Kepone was removed from solution with an efficiency similar to that of another column containing immobilized activated charcoal. On the other hand, the hydrophobic resin adsorbant XAD‐2 was not as efficient. Hydrophobic partitioning was not the entire explanation, as the hydrophobic aflatoxin G1was not bioaccumulated and living algal cells were much more effective than formalin killed cells at bioaccumulation of Kepone. Neither Kepone nor aflatoxin G1were biodegraded by the algae.

ISSN:0360-1226    

DOI:10.1080/10934528109374962

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Polychlorinated biphenyls (PCBs) are highly lipophilic molecules that are now widely distributed throughout the environment. They tend to accumulate in the adipose tissue and thus remain as a source of continuing exposure to the rest of the body. The interaction of some of the representative PCBs with phospholipid bilayer membranes was monitored by the spin label technique. Under identical experimental conditions, it was found that an increase in chlorine substitution in the 2,2’, 6,6'‐positions of the biphenyl rings enhances the motion of the spin label in the bilayer membrane. It is proposed that the perturbation which increases the membrane fluidity can be correlated to the degree of non‐coplanarity of the biphenyl rings incorporated into the bilayer membranes.

ISSN:0360-1226    

DOI:10.1080/10934528109374963

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0360-1226    

DOI:10.1080/10934528109374964

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Stream muds and sediments, contaminated with arsenic from an industrial waste water, have been studied, under laboratory conditions, for release of this contaminant to overlying waters. The arsenic content of the muds was determined initially whereupon simulated reservoirs were prepared from these muds and natural stream water. The systems studied were: anaerobic conditions at 25o, 20o, 15°, 10°, and 4°C, aerobic conditions at 20°and 10°C with dissolved oxygen (DO) levels of 100%, 50%, 25%, and 10% saturation. Distribution coefficients, the dimensionless ratio of AS /AS ,, were determined. In both the water mud aerobic and anaerboic systems, lower temperatures produced smaller distribution coefficients (those in the 4–10oC range were about 40% of the coefficients at the higher 20–25°C range). Very little difference was found in the distribution coefficients at a given temperature between reservoirs having either 10%, 25%, 50%, or 100% of saturation of dissolved oxygen. Anaerobic conditions led to levels of arsenic, principally as As (+III), about ten times higher than concentrations reached with aerobic conditions. The ratio of anaerobic As level/aerobic As level in reservoir waters was decreased also with decreasing temperature (8.3 at 25°C, and 5.6 at 10°C). The arsenic in the aerobic reservoirs was found to be about 70% arsenate, and 20% organic‐arsenic. Little pH effect was observed over a pH range of 6.0 to 8.5.

ISSN:0360-1226    

DOI:10.1080/10934528109374965

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

HANDBOOK OF ENVIRONMENTAL HEALTH AND SAFETY: PRINCIPLES AND PRACTICES Herman Koren lxxvi + 698 pages Pergamon Press, Inc. New York 1980 Hard cover $95.00

ISSN:0360-1226    

DOI:10.1080/10934528109374966

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0360-1226    

DOI:10.1080/10934528109374957

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor