Radon-222 from the island of hawaii: deep soils are more important than lava fields or volcanoes

The mean flux of radon-222 atoms from the island of Hawaii is 0.45 atom per square centimeter per second. Lava fields occupy 50 percent of the land area, but their radon flux is only 1 percent of that from deep volcanic soils. The island yields approximately 10 curies of radon-222 per hour to the air surrounding it. The radon-222 contribuition of volcanoes is negligible.     

Radium-226 and radon-222: concentration in atlantic and pacific oceans

Measurements of radon-222 in seawater suggest the following. The radium-226 content of surface water in both the Atlantic and Pacific oceans is uniformly close to about 4 x 10(-14) gram per liter. The deep Pacific has a concentration of radium-226 that is four times higher and the deep Atlantic a concentration twice as high as that of the surface. These distribution profiles can be explained by the same particle-settling rate for radium-226 from surface to depth for the two oceans and by a threefold longer residence time of water in the deep Pacific than in the deep Atlantic. The vertical distribution of the deficiency of radon-222 in the surface water of the northwest Pacific Ocean suggests a coefficient of vertical eddy diffusion as high as 120 square centimeters per second and a gas-exchange rate for carbon dioxide in surface water between 14 and 60 moles per square meter per year. Vertical profiles of the excess of radon-222 in near-bottom water of the South Atlantic give coefficients of vertical eddy diffusion ranging from 1.5 to more than 50 square centimeters per second.     

Radon-222 in the North Atlantic trade winds: its relationship to dust transport from Africa

The concentration of radon-222 in air was measured during a flight from Miami to Barbados to Dakar and return; concentrations ranged from 1 to 55 picocuries per standard cubic meter of air and were highest in areas of dense haze, which were present along most of the flight path across the Atlantic Ocean. The haze is attributed to dust originating from the arid regions of western Africa. Radon-222 may be useful as a tracer for African air parcels over the equatorial Atlantic.     

Distribution of airborne radon-222 concentrations in U.S. homes

Apparently large exposures of the general public to the radioactive decay products of radon-222 present in indoor air have led to systematical appraisal of monitoring data from U.S. single-family homes; several ways of aggregating data were used that take into account differences in sample selection and season of measurements. The resulting distribution of annual-average radon-222 concentrations can be characterized by an arithmetic mean of 1.5 picocurie per liter (55 becquerels per cubic meter) and a long tail with 1 to 3% of homes exceeding 8 picocuries per liter, or by a geometric mean of 0.9 picocurie per liter and a geometric standard deviation of about 2.8. The standard deviation in the means is 15%, estimated from the number and variability of the available data sets, but the total uncertainty is larger because these data may not be representative. Available dose-response data suggest that an average of 1.5 picocuries per liter contributes about 0.3% lifetime risk of lung cancer and that, in the million homes with the highest concentrations, where annual exposures approximate or exceed those received by underground uranium miners, long-term occupants suffer an added lifetime risk of at least 2%, reaching extraordinary values at the highest concentrations observed.     

Primordial radioelements and cosmogenic radionuclides in lunar samples from apollo 15

Two basalts, two breccias, and two soils from Apollo 15 were analyzed by nondestructive gamma-ray spectrometry. The concentrations of potassium, thorium, and uranium in the basalts were similar to those in the Apollo 12 basalts, but the potassium: uranium ratios were somewhat higher. Primordial radioelements were enriched in the soils and breccia, consistent with a two-component mixture of mare basalt and up to 20 percent foreign component (KREEP). The abundance patterns for cosmogenic radionuclides implied surface sampling for all specimens. The galactic cosmic-ray production rate of vanadium-48 was determined as 57 +/- 11 disintegrations per minute per kilogram of iron. Cobalt-56 concentrations were used to estimate the intensity of the solar flare of 25 January 1971.     

Aluminum-26 and beryllium-10 in marine sediment

Activities of aluminum-26 and beryllium-10 in marine sediment were measured at 0.01 +/- 0.13 and 4.4 +/- 0.9 disintegrations per minute, per kilogram dry weight, respectively. Only an upper limit of 0.03 could be determined for the ratio of aluminum-26 to beryllium-10 in the sediment. The ratio is probably explained by production by cosmic rays in the atmosphere.     

Nickel-63 in marine and terrestrial biota, soil, and sediment

A previously unreported radionuclide, nickel-63 (half-life, 92 years), produced in the testing of nuclear devices, was measured in biological and environmental samples from areas of the Pacific Ocean and the eastern seaboard of the United States. The concentrations of nickel-63 are low (maximum of 163 disintegrations per minute per gram of dry weight), but this radionuclide may be a useful tracer of oceanic processes because of its long half-life and long residence time in the ocean.     

Atmospheric carbon dioxide: its role in maintaining phytoplankton standing crops

The rate of invasion of carbon dioxide into an artificially eutrophic Canadian Shield lake with insufficient internal sources of carbon was determined by two methods: measuring the carbon : nitrogen : phosphorus ratios of seston after weekly additions of nitrogen and phosphorus, and measuring the loss of radon-222 tracer from the epilimnion. Both methods gave an invasion rate of about 0.2 gram of carbon per square meter per day. The results demonstrate that invasion of atmospheric carbon dioxide may be sufficient to permit eutrophication of any body of water receiving an adequate supply of phosphorus and nitrogen.     

Internal winds in water lilies: an adaptation for life in anaerobic sediments

The network of internal gas spaces in the yellow water lily constitutes a pressurized flow-through system which forces oxygen to the roots and rhizome buried in the anaerobic sediment. By the purely physical processes of thermal transpiration and hygrometric pressure, several liters of air per day enter the young, newly emerged leaves of Nuphar luteum against a small pressure gradient. This air moves en masse down the petioles of the young leaves (at rates up to 50 centimeters per minute) to the rhizome, forcing a simultaneous flow of gas (rich in carbon dioxide) from the rhizome up the petioles of the older emergent leaves to the atmosphere. The ventilation system has important physiological and ecological consequences.     

Detection of radon emanation from the crater aristarchus by the apollo 15 alpha particle spectrometer

The alpha particle spectrometer aboard the Apollo 15 command/service module was designed to detect alpha particles from radon decay and to locate regions with unusual activity on the moon. A significant increase in radon-222 activity was detected from a region containing the crater Aristarchus. The result is interpreted as probably indicating internal activity at the site. By analogy with terrestrial processes, increased radon emanation may be associated with the emission of other volatiles.     

Detection of a nonuniform distribution of polonium-210 on the moon with the apollo 16 alpha particle spectrometer

The polonium-210 activity of the lunar surface is significantly larger than the activity of its progenitor radon-222. This result establishes unequivocally that radon emanation from the present-day moon varies considerably within the 21-year half-life of lead-210, the parent nuclide of polonium-210. There are large variations and well-localized enhancements in polonium-210 activity over much of the moon's surface.     

Tritium and argon radioactivties in lunar material

Tritium and argon radioactivities, attributable to galactic and solar cosmic-ray interactions, were measured in lunar soil and in three lunar rocks. The tritium in the soil, 325 +/- 17 disintegrations per minute per kilogram, is slightly higher than that in the rocks, 212 to 250 dpm/kg. For two rocks, the tritium was combined with the helium-3 in order to calculate exposure ages of 375 +/- 40 and 205 +/- 25 million years. The argon-37 radioactivities, 21.0 to 27.2 dpm/kg, and the argon-39 radioactivities, 12.1 to 16.4 dpm/kg, are slightly higher than those in stony meteorites. Higher exposure ages were obtained from the argon isotopes than from tritium and helium-3. On the basis of the known galactic cosmic-ray flux and the known cross section, at least half of the observed radioactivities are produced by solar cosmic rays.     

Measurements of the stratospheric plume from the mount st. Helens eruption: radioactivity and chemical composition

Gas measurements made in the stratospheric plume from the eruption of Mount St. Helens on 18 May 1980 were not consistent with a reported large injection of radon-222 into the atmosphere. No enrichment in the volatile element polonium was found in filter samples, and the ratio of polonium-210 to lead-210 was not different from background values. Data obtained with an experimental impactor, flown shortly after the eruption, showed an increase of 10(3) in the stratospheric number concentration of submicrometer sulfate particles compared to concentrations before the eruption.     

Sediment-Water Chemical Exchange in the Coastal Zone Traced by in situ Radon-222 Flux Measurements

In situ radon-222 flux experiments conducted in benthic chambers in Cape Lookout Bight, a small marine basin on the North Carolina coast, reveal that enhanced chemical transport across the sediment-water interface during summer months is caused by abiogenic bubble tube structures. Transport rates for dissolved radon, methane, and ammonium more than three times greater than those predicted on the basis of molecular diffusion occur when open tubes are maintained by semi-diurnal low-tide bubbling.     

Detection of radon emission at the edges of lunar maria with the apollo alpha-particle spectrometer

The distribution of radioactive polonium-210, a decay product of radon-222, shows enhanced concentrations at the edges of lunar maria. Enhancements are seen at the edges of Mare Fecunditatis, Mare Crisium, Mare Smythii. Mare Tranquillitatis, Mare Nubium, Mare Cognitum, and Oceanus Procellarum. The observation is indicative of the transient emission of radon gas from the perimeters of lunar maria.     

A system for preparing and distributing large volumes

A systein for preparing and distributing 100 liters of distilleddeionized water per day is described. Novel features are an overflow regulator, a " barometer " tube (permitting secondary reservoirs), and a pressure-controlled shutoff valve.     

Gaseous constituents in the plume from eruptions of mount st. Helens

Measurements in the stratosphere of gaseous constituents in the plume of Mount St. Helens were obtained during five flights of the NASA U-2 aircraft between 19 May and 17 June 1980. Mixing ratios from gas chromatographic measurements on samples acquired about 24 hours after the initial eruption show considerable enhancement over nonvolcanic concentrations for sulfur dioxide (more than 1000 times), methyl chloride (about 10 times), and carbon disulfide (more than 3 times). The mixing ratio of carbonyl sulfide was comparable to nonvolcanic mixing ratios although 3 days later it was enhanced two to three times. Ion chromatography measurements on water-soluble constituents are also reported. Very large concentrations of chloride, nitrate, and sulfate ions were measured, implying large mixing ratios for the water-soluble gaseous constituents from which the anions are derived. Measurements of radon-222 present in the plume are also reported.     

48;催杀胶悬剂喷雾防治棉铃虫试验

研究了生物杀虫剂48;催杀胶悬剂在南疆棉田防治棉铃虫的效果和使用方法.结果表明:药液25 L/667m2常规喷雾方法极显著优于667 mL/667m2超低容量喷雾方法;12 mL/667m2 48;催杀胶悬剂常规喷雾和9 mL/667m2 48;催杀胶悬剂常规喷雾有极显著的防治效果,喷药后1、3和7 d的防治效果分别为76.82;和79.83;、61.9;和65.08;、84;和88;,二者之间无差异,均明显优于6 mL/667m248;催杀胶悬剂常规喷雾.鉴于其对自然天敌比较安全,认为可以将该生物农药纳入新疆棉花IPM之中.     

Continuous gas chromatography

Continuous gas chromatography has been achieved with a radialflow chromatographic channel free of packing and formed between two closely spaced (50 to 75 microns) disc surfaces (optically flat and solvent-coated) rotating at one-half or one revolution per second. This technique provides high capacity and immediate response (in a fraction of a second). Mixtures of hydrocarbon gases have been separated at flow rates of 6 to 30 cubic centimeters per minute with 100 to 150 cubic centimeters per minute of nitrogen carrier gas in a chromatographic channel only 39 millimeters long.     

丁香油和MS-222对大泷六线鱼幼鱼的麻醉效果

为研究丁香油和MS-222麻醉剂对大泷六线鱼Hexagrammos otakii的麻醉效果,选择体质量为(83.3±7.8)g的大泷六线鱼幼鱼进行试验,根据大泷六线鱼被麻醉和复苏时的行为特征,将整个麻醉过程分为10期,其中麻醉6个时期,复苏4个时期。结果表明:丁香油浓度在50~100 mg/L、MS-222浓度在50~70 mg/L时鱼体均可在3 min内入麻并均可在5 min内复苏;当丁香油浓度≥100 mg/L、MS-222浓度≥70 mg/L时,鱼体在麻醉液中浸浴15 min后部分鱼体出现休克死亡;用丁香油麻醉鱼时,整个麻醉过程中鱼体的呼吸频率呈下降趋势,而用MS-222麻醉鱼时,鱼体在达到4期阶段后呼吸频率明显加快,但仅见鳃盖后缘小幅度张合;鱼体进入深度麻醉以后在空气中暴露时间越长,鱼体复苏所需时间就越长,用丁香油或MS-222麻醉的鱼体可在空气中分别暴露7、5 min。研究表明,丁香油和MS-222均对大泷六线鱼幼鱼有良好的麻醉效果,具有入麻时间短、复苏快的特点,两者均可作为大泷六线鱼理想的麻醉剂。