scholarly journals Commentary: Low-Level Exposures: Some Implications for the U.S. Department of Energy

1998 ◽  
Vol 106 ◽  
pp. 383
Author(s):  
James R. Beall
Keyword(s):  
Department Of Energy ◽  
Low Level ◽  
The U.S

Micropollutants Produced by Disinfection of Wastewater Effluents*

1982 ◽  
Vol 14 (12) ◽  
pp. 45-59 ◽  
Author(s):  
R L Jolley ◽  
R B Cumming ◽  
N E Lee ◽  
J E Thompson ◽  
L R Lewis
Keyword(s):  
Wastewater Treatment ◽  
Uv Irradiation ◽  
Base Pair ◽  
Wastewater Treatment Plants ◽  
Department Of Energy ◽  
Union Carbide Corporation ◽  
Organic Constituents ◽  
Chemical Effects ◽  
Base Pair Substitution ◽  
The U.S

The principal objective of this research program was to examine the effects of disinfection by chlorine, ozone, and ultraviolet light (uv) irradiation on nonvolatile organic constituents relative to chemical effects and the formation of micropollutants. In a comparative study of highly concentrated samples of effluents from nine wastewater treatment plants, it was determined that disinfection with chlorine or ozone both destroys and produces nonvolatile organic constituents including mutagenic constituents. The chemical effects of disinfection by uv irradiation were relatively slight, although the mutagenic constituents in one effluent were eliminated by this treatment. The nine wastewater treatment plants were selected by using the following criteria: disinfection method, nature of wastewater source, type of wastewater treatment, standards for quality of treatment, and geographical location. The treatment plants varied from pilot plant and small plants [0.05 m3/s (1 Mgd)] treating principally domestic waste to large plants [4.4 m3/s (100 Mgd)] treating principally industrial waste. Four plants used only chlorine for disinfection, four used ozone for disinfection, and one used uv irradiation for disinfection. Eight treatment plants used conventional secondary or more advanced wastewater treatment, and one plant used primary treatment. The following methodology was used in this investigation: grab sample collection of 40-L samples of undisinfected and disinfected effluents; concentration of the effluents by lyophilization; high-pressure liquid chromatographic separation of nonvolatile organic constituents in effluent concentrates using uv absorbance, cerate oxidation, and fluorescence detectors; bacterial mutagenicity testing of concentrates and chromatographic fractions; and identification and characterization of nonvolatile organic constituents in mutagenic HPLC fractions. With these procedures, over 100 micropollutants were identified in the wastewater effluent concentrates. Interplant comparison revealed considerable variability in the presence of mutagenic nonvolatile organic constituents in the undisinfected effluent concentrates as well as much variability in the destruction of the mutagenic constituents and the formation of other mutagenic constituents as a result of disinfection. Moreover, the effects varied on samples collected at the same wastewater treatment plant at different periods. No micropollutants known to be mutagens were identified in the mutagenic HPLC fractions separated from the undisinfected, chlorinated, and ozonated effluent concentrates. The mutagenic activity of the nonvolatile organic constituents in one chlorinated effluent concentrate was not attributable to organic chloramines. Most of the mutagens detected in effluent concentrates are direct acting and do not require metabolic activation. Both base-pair substitution mutagens and frame-shift mutagens occurred in the wastewater concentrates, but the former type was more frequent. For many of the compounds in effluents, strain TA-1535 was more sensitive than strain TA-100 in detecting base-pair substitution mutagens. *Research sponsored by the U.S. Department of Energy and the U.S. Environmental Protection Agency. The work was carried out at the Oak Ridge National Laboratory, which is operated by the U.S. Department of Energy under contract W-7405-eng-26 with the Union Carbide Corporation.

scholarly journals Geographic Shift and Environment Change of U.S. Tornado Activities in a Warming Climate

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 567
Author(s):  
Zuohao Cao ◽  
Huaqing Cai ◽  
Guang J. Zhang
Keyword(s):  
Wind Shear ◽  
Convective Available Potential Energy ◽  
Geographic Location ◽  
Reanalysis Data ◽  
Cyclonic Circulation ◽  
Upward Motion ◽  
Environment Change ◽  
Low Level ◽  
High Event ◽  
The U.S

Even with ever-increasing societal interest in tornado activities engendering catastrophes of loss of life and property damage, the long-term change in the geographic location and environment of tornado activity centers over the last six decades (1954–2018), and its relationship with climate warming in the U.S., is still unknown or not robustly proved scientifically. Utilizing discriminant analysis, we show a statistically significant geographic shift of U.S. tornado activity center (i.e., Tornado Alley) under warming conditions, and we identify five major areas of tornado activity in the new Tornado Alley that were not identified previously. By contrasting warm versus cold years, we demonstrate that the shift of relative warm centers is coupled with the shifts in low pressure and tornado activity centers. The warm and moist air carried by low-level flow from the Gulf of Mexico combined with upward motion acts to fuel convection over the tornado activity centers. Employing composite analyses using high resolution reanalysis data, we further demonstrate that high tornado activities in the U.S. are associated with stronger cyclonic circulation and baroclinicity than low tornado activities, and the high tornado activities are coupled with stronger low-level wind shear, stronger upward motion, and higher convective available potential energy (CAPE) than low tornado activities. The composite differences between high-event and low-event years of tornado activity are identified for the first time in terms of wind shear, upward motion, CAPE, cyclonic circulation and baroclinicity, although some of these environmental variables favorable for tornado development have been discussed in previous studies.

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