Paul Merolla, Douglas Mose and George Mushrush, Chemistry Department, George Mason University, Fairfax, VA 22030, Tel/Fax: 703-273-2282, Email: Dje42@aol.com

Measurements of radon emanation in soil gas exhibit changes related to the water table. A rising water table causes an increase in radon emanation while a falling water table causes a decrease.  These changes are thought to be related to the decrease or increase in the pore spaces throughout which the soil gas radon can be distributed.  When the water table stabilizes at relatively high levels, the radon emanation slowly deceases while if the water table stabilizes at relatively deep levels, the radon emanation slowly increases.  These changes are thought to be related to the lesser or greater availability of water-free pore spaces which can generate mobile radon.  These patterns may serve to explain unanticipated changes in indoor radon concentrations. 

Radioecology of Lake Sevan Basin, Armenia

Armen Stepanyan, PhD Student, Center for Ecological-Noosphere Studies (CENS), National Academy of Sciences (NAS), RA, Yerevan, 375025, 68 Abovian Str., Armenia, Tel: +(374-1)-569331, +(374-9)-424860, Email: h_armenian@hotmail.com 
Anna Nalbandyan, PhD Student, Laureate of Gulbekian Award, Center for Ecological-Noosphere Studies (CENS), National Academy of Sciences (NAS), RA, Yerevan, 375025, 68 Abovian Str., Armenia Tel: +(374-1)-569331, Email: annag@freenet.am
Armen Kyureghyan, M.Sc., Center for Ecological-Noosphere Studies (CENS), National Academy of Sciences (NAS), RA, Yerevan, 375025, 68 Abovian Str., Armenia, Tel: +(374-1)-569331 , Email: armen_ec@yahoo.com 
Viktoria Ananyan, Doctor of Biological Sciences, Center for Ecological-Noosphere Studies (CENS),  National Academy of Sciences (NAS), RA, Yerevan, 375025, 68 Abovian Str., Armenia, Tel: +(374-1)-56933, Email: ecocentr@sci.am

The Lake Sevan is among the largest highland freshwater lakes in the world. Its basin represents an inter-mountain depression whose central part is occupied by the lake. The maximum elevations of ridges are 3300-3579 m and the coastline areas are at 2000 m above sea level. Investigations of environmental radioactivity in Sevan basin and in the lake itself have the strategic importance, since this waterbody is the only guaranteed source of fresh water in Armenia and all South Caucasus. Since 1933, lake water has been used for hydropower and irrigation. Before now, the lake level has subsided by 18.8 m and its surface area has shrunk by 12%. Human effect has caused the disturbance of environmentally sustainable status of the lake. Armenia has been conducting different studies of different issues regarding the environmental and technical requirements for preservation of this lake as the source of fresh water, fisheries, recreation, etc.

One of the issues is radioecology, i.e. the studies of radioactivity of soil, vegetation, water, and bottom sediments. These studies in Sevan were launched in 1952 and are running now. The principal soil is black earth. The level of natural radioactivity of soil assessed in terms of gross radionuclides (uranium, radium, thorium, potassium, and rubidium) averages 475 Bq/kg. In 1994, beta-radioactivity of soil was mainly within the natural range (500-600 Bq/kg) and only 20% of samples had some increased concentrations. The highest level of radioactivity in meadow vegetation was documented in 1962 – 3718 Bq/kg dry wt. In 1989 beta-radioactivity decreased down to 975 Bq/kg. Potassium radioactivity in vegetation made about 500 Bq/kg. The moss sample dated 1988 contained 270 Bq/kg dry wt of 137-Cs. In this relation, the studies have been started together with Prof. William C. Burnett from Florida State University and Assist. Prof. Jaye E. Cable from Louisiana State University, USA within the project ”Paleoecology and paleo-radioecology of Lake Sevan”. First results have revealed the presence of 137-Cs in surface (0-50 cm) layer of bottom deposits sampled from depth 54 m. Potassium and radium are also present.

References:

1. Geology of Sevan, NAS RA, Institute of Geological Sciences, Y.- 1994, pp.168.
2.  Ecological Problems of Lake Sevan, NAS RA, Institute of Hydroecology and Ichtiology, Y.- 1993, pp. 88.
3. Geochemistry of Natural Waters of Lake Sevan Catchment, NAS RA, Publ. ”Gitutyun”, Y.- 1997, pp. 282.

Correlation Test Between Indoor Radon and Surficial Gamma Radiation in Northern Virginia

George Saiway, George Mushrush and Douglas Mose, Chemistry Department, George Mason University, Fairfax, VA 22030, Tel/Fax: 703-273-2282, Email: Dje42@aol.com

In northern Virginia, significant indoor radon differences occur between nearby communities.  Studies reveal these differences to be correlated with soil chemistry and permeability.  Homes constructed in the soil developed over the Peters Creek Schist almost all exceed the USEPA=s MCL of 2 pCi/L for homeowners, and over 50% exceed the USEPA=s MCL of 4 pCi/L for home buyers. In this study group, home construction seems not important except that homes with electrical heating systems averaged almost 2 pCi/L higher than homes with gas and oil furnaces.  It was unanticipated that total-gamma radiation in this soil was not homogeneous, but comparisons between indoor radon and soil gamma radiation show a positive correlation, suggesting that soil aeroradioactivity measurements can delineate areas with a high potential for indoor radon. 

Reduction of Radon in Municipal Wells in Virginia and Maryland

Fiorella Simoni, George Mushrush and Douglas Mose, Chemistry Department, George Mason University, Fairfax, VA 22030, Tel/Fax: 703-273-2282

Approximately 10% of the homes in northern Virginia use well water, and our measurements show that some exceed 4000 pCi/L, the average is about 2000 pCi/L, and few have waterborne radon as low as 300 pCi/L, the USEPA's recommended Maximum Concentration Level. In this area, granitic rocks yield well water with about 3000 pCi/L, felsic metamorphic rocks yield well water with about 2000 pCi/L, and quartz-rich sedimentary rocks average about 1000 pCi/L. Tests of remediation technology showed that passing water through large tanks of activated charcoal removes about 90% of the waterborne radon, but the charcoal becomes less efficient over a few months. Aeration experiments using a blade or experiments using a splash box in large community storage tanks each removed about 60-70% of the waterborne radon, but using both removed about 90%, and the combination does not become less effective through time.

Top