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Natural radon concentrations in the Earth's atmosphere are so low that radon-rich water in contact with the atmosphere will continually lose radon by volatilization. Hence, ground water has a higher concentration of 222 Rn than surface water , because radon is continuously produced by radioactive decay of 226 Ra present in rocks.
Most water in Earth's atmosphere and crust comes from saline seawater, while fresh water accounts for nearly 1% of the total. The vast bulk of the water on Earth is saline or salt water, with an average salinity of 35‰ (or 3.5%, roughly equivalent to 34 grams of salts in 1 kg of seawater), though this varies slightly according to the amount of runoff received from surrounding land.
The results of a methodical ten-year-long, case-controlled study of residential radon exposure in Worcester County, Massachusetts, found an apparent 60% reduction in lung cancer risk amongst people exposed to low levels (0–150 Bq/m 3) of radon gas; levels typically encountered in 90% of American homes—an apparent support for the idea of ...
Radon is thus assumed to be the second leading cause of lung cancer after smoking, and accounts for 15,000 to 22,000 cancer deaths per year in the US alone. [9] [better source needed] However, the discussion about the opposite experimental results is still going on. [10] About 100,000 Bq/m 3 of radon was found in Stanley Watras's basement in 1984.
It is radioactive due to the presence of naturally occurring uranium (5–10 ppm) and thorium, and their daughter nuclides radium, radon, polonium, etc. Marine-deposited phosphate typically has a higher level of radioactivity than igneous phosphate deposits, because uranium is present in seawater at about 3 ppb (roughly 85 ppb of total ...
3.48 neon-32: 3.5 darmstadtium-277: 3.5 protactinium-211: 3.8 lead-179: 3.9 roentgenium-278: 4 radium-203: 4 seaborgium-260: 4 uranium-216: 4.3 beryllium-14: 4.35 lead-180: 4.5 radon-196: 4.7 fluorine-27: 5 bismuth-189m1: 5.0 francium-214: 5.0 meitnerium-277: 5 nobelium-262: 5 polonium-189: 5 boron-17: 5.08 protactinium-223: 5.1 americium-223: ...
This is a list of bodies of water by salinity that is limited to natural bodies of water that have a stable salinity above 0.05%, at or below which water is considered fresh. Water salinity often varies by location and season, particularly with hypersaline lakes in arid areas, so the salinity figures in the table below should be interpreted as ...
The water policy of the European Union is primarily codified in three directives: Directive on Urban Waste Water Treatment (91/271/EEC) of 21 May 1991 concerning discharges of municipal and some industrial wastewaters; The Drinking Water Directive (98/83/EC) of 3 November 1998 concerning potable water quality;