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PubMed2001

PAH deposition to snow surface. Chemical analysis and interpretation of results.

The urban snowpack effectively acts as a collection device for atmospheric-deposited PAHs. When these PAHs are flushed out in a short time interval along with springtime snowmelt, these cause shockloading to receiving waters. In order to assess the PAH deposition and accumulation in urban snowpacks, a deposition survey of PAH for the winter months of 1991-92 from the city of Sault Ste. Marie, Ontario, Canada was undertaken. The results of the survey are interpreted in view of prevailing meteorology and various emission sources in the study area. The relative PAH deposition levels (to BaP) are compared with relative source emission fingerprints to examine consistency in sampling and analysis. While analyzing the PAH samples using the ASTM (1987) method, the problem of concentration levels being below the detection level was encountered. The ASTM method for PAH analysis was modified to enhance the detection limit of the PAHs by concentrating the PAH extract to very low volumes, on the order of 200-300 microL.

Chemistry Techniques, Analytical↗
PubMedDate not supplied

Intracranial hypotension and recurrent pleural effusion after snow-boarding injury: a manifestation of cerebrospinal fluid-pleural fistula.

BACKGROUND DATA: Intracranial hypotension causing postural headaches has been described after occult and postsurgical cerebrospinal fluid (CSF) leaks and rarely isolated lumbar punctures. The occurrence of a CSF-pleural communication is much rarer, and a high level of suspicion aids in prompt recognition. PURPOSE: Early detection and anatomic delineation of the site of CSF-pleural fistula allows prompt intervention, results in resolution of symptoms and prevents the complication of meningitis. STUDY DESIGN: A case of intracranial hypotension with postural headaches is described after spinal surgery, with demonstration on computed tomography (CT) myelography of a rare CSF-pleural fistula. METHODS: The clinical presentation, postoperative intervention and imaging as well as laboratory data are presented. RESULTS: Chest X-ray showed recurrent pleural effusion after placement of chest tube, and serial head CT studies revealed decreasing ventricular size with development of severe headaches. Myelogram and CT postmyelogram demonstrate the CSF-pleural communication, allowing appropriate surgical repair. CONCLUSION: Severe headaches with a recurrent pleural effusion after thoracic spinal surgery may indicate presence of a CSF-pleural fistula, an unusual complication of thoracic spinal surgery.

Adolescent↗
PubMed2001

Post-World War II uranium changes in dated Mont Blanc ice and snow.

Recent controversies concerning the possibility of environmental contamination due to the use of uranium in classical weaponry have led us to realize that there is a lack of time series for this metal from environmental archives. We have therefore performed analysis of a dated 140 m-long ice/snow core that was drilled in 1994 at a cold high altitude site (4250 m) near the summit of Mont Blanc in the French-Italian Alps. Ultraclean analytical procedures were employed in our analyses. Uranium concentrations were determined by inductively coupled plasma sector field mass spectrometry. In ice dating from before the 1940s, uranium concentrations are found to have remained fairly constant and can be explained simply by a crustal contribution. For the post-World War II layers, on the other hand, the data show large excesses above crustal contributions. These uranium excesses are attributed to tropospheric transport of dust emitted during extensive mining and milling operations which took place in the GDR and to a smaller extent in France at that time. There is no enhancement in uranium concentrations in the ice layer in which fallout from the 1986 Chernobyl accident was previously identified from a gross beta activity vs depth profile.

Altitude↗
PubMed2004

Post-17th-century changes of European lead emissions recorded in high-altitude alpine snow and ice.

Lead concentrations and lead isotope ratios were analyzed in two firn/ice cores covering the period from 1650 to 1994, which were obtained from the 4450 m high glacier saddle Colle Gnifetti located in the Monte Rosa massif at the Swiss-Italian border. This study presents the first glaciochemical time series with annual resolution, spanning several centuries of lead concentrations and lead isotopic compositions in precipitation in Europe. Lead concentrations in firn dated from the 1970s are approximately 25 times higher than in ice dated from the 17th century, confirming the massive rise in lead pollution in Europe during the last few centuries. A decline of the lead concentration is then observed during the last two decades, i.e., from 1975 to 1994. The lead isotope ratio 206Pb/207Pb decreased from about 1.18 in the 17th and 18th centuries to about 1.12 in the 1970s. These variations are in good agreement with available information on variations in anthropogenic lead emissions from West European countries, especially from the use of lead additives in gasoline.

Air Pollutants↗
PubMed2006

Atmospheric deposition of current-use and historic-use pesticides in snow at national parks in the western United States.

The United States (U.S.) National Park Service has initiated research on the atmospheric deposition and fate of semi-volatile organic compounds in its alpine, sub-Arctic, and Arctic ecosystems in the Western U.S. Results for the analysis of pesticides in seasonal snowpack samples collected in spring 2003 from seven national parks are presented herein. From a target analyte list of 47 pesticides and degradation products, the most frequently detected current-use pesticides were dacthal, chlorpyrifos, endosulfan, and gamma-hexachlorocyclohexane, whereas the mostfrequently detected historic-use pesticides were dieldrin, alpha-hexachlorocyclohexane, chlordane, and hexachlorobenzene. Correlation analysis with latitude, temperature, elevation, particulate matter, and two indicators of regional pesticide use reveal that regional current and historic agricultural practices are largely responsible for the distribution of pesticides in the national parks in this study. Pesticide deposition in the Alaskan parks is attributed to long-range transport because there are no significant regional pesticide sources. The percentage of total pesticide concentration due to regional transport (%RT) was calculated for the other parks. %RT was highest at parks with higher regional cropland intensity and for pesticides with lower vapor pressures and shorter half-lives in air.

Agriculture↗