خيارات البحث
النتائج 151 - 160 من 213
Sampling of glacial snow for pesticide analysis
1971
Stengle, Thomas R. | Lichtenberg, James J. | Houston, Charles S.
Snow samples were taken from the plateau glacier of Mt. Logan, Y.T., Canada during an investigation intent on demonstrating the feasibility of taking such samples from high altitude snowfields for pesticide analysis and developing sampling techniques devoid of contamination. Samples were also taken at a depth of 15 m to determine whether DDT concentration varied with the age of the snow. Pesticide analyses were performed using vapor phase chromatographic techniques. DDT was not detected within the limit of detectability (5 ng/l). Over half the samples were contaminated with PCB's which raised the detectability limit to 10-50 ng/1. The PCB contamination is believed to have come from the sampling auger, as an analysis of rinsings from it seemed to confirm. A sample taken from a depth of 1.5-2.5 m was acidified with distilled nitric acid, when thawed, and analyzed for 19 elements simultaleously using a direct reading emission spectrometer. Four elements were detected: boron at 4 ng/ml, cadmium at 9 ng/ml, chromium at 2 ng/ml, and iron at 47 ng/ml. The high levels of cadmium and especially iron suggest contamination from the alloy steels of the auger.
اظهر المزيد [+] اقل [-]Environmental control in the organic and petrochemical industries, 1971
1971
Jones, H. R. (Harold R)
State-of-art, sugarbeet processing waste treatment
1971
Fischer, James A. | Hungerford, Edward H.
Environmental pollution by fluorides in Flathead National Forest and Glacier National Park
1971
Carlson, Clinton E. | Dewey, Jerald E.
Oxygen regeneration of polluted rivers: the Passaic River
1971
Whipple, William
Characterization of taste and odors in water supplies
1971
Collins, Ralph P.
A microbiological survey in Lake Erie near Cleveland, Ohio
1971
Collins, Ralph P.
Periodic taste and odor at the Cleveland, Ohio Crown Water Treatment Plant prompted investigation of the role microorganisms play in the problem. Fungi, bacteria, and algae collected near the plant intake were studied during June through August 1971. During the three months of sampling, no vertical distribution pattern was noted in quantitative analysis of the phytoplankton. A number of algae, reported to induce taste and odor in water, were identified. Whatever the source of these odors, they were not due to benthic or periphyton algae, but could have been associated with the phytoplankton community as the reported 'Lake Erie odor' coincided with phytoplankton increase.
اظهر المزيد [+] اقل [-]Dispatching system for control of combined sewer losses
1971
Air pollution aspects of emission sources: municipal incineration
1971
Advanced nonthermally polluting gas turbines in utility applications
1971
Biancardi, F. R. | Peters, G. T. | Landerman, A. M.
