River Bottom Sediments Research Articles

Studies on Movement of <SUP>90</SUP>Sr, <SUP>106</SUP>Ru, <SUP>137</SUP>Cs, <SUP>144</SUP>Ce in Environment, connected with the City Water Supply

In order to examine radioecologically behavior of radionuclides in environment of water supply, levels of radionuclides in the soil, raw water from river and its suspension, river bottom sediment, and water supplied for drinking were quantitatively investigated, and then various aspects on transfer of radionuclides in the land, river, and water works were hydrometeorologically analyzed. On three basins, Agano, Edo, and Yodo River, movements of 106Ru, 137Cs and 144Ce were derived from data of 90Sr. 90Sr was removable compared with other radionuclides in various samples. The following equations were established by the regression analysis between "ratio on each of the radionuclides to 90Sr" in soil (Rd) and that of river bottom sediment (RBS), between Rd and that in river water with suspension (R[W+S]), and between radionuclides concentration in the river water (C ; pCi/100 liter) and weight of the river suspension (S ; gr. of ash/100 liter). [numerical formula] Coefficients a1 and b1 were 8.46-1.35 and 2.35-0.62 for 106Ru, 4.14-0.989 and 2.58-0.31 for 144Ce, and 2.80-0.836 and 3.49-0.879 for 137Cs, respectively. The a2 and b2 for 137Cs were 0.085-0.055 and 0.26-0.19. The a3 and b3 in the Agano River were 0.00229 and 1.49 for 90Sr, and 0.0229 and 0.64 for 137Cs. These data indicated that the degree of deposition to the soil, adsorption, and absorption to the river bottom of 106Ru, 137Cs and 144Ce are higher than those of 90Sr, in the following order : 106Ru>144Ce>137Cs>90Sr. As for the pathway of contamination, part of 90Sr is soluble and most of 106Ru, 137Cs and 144Ce is insoluble in the river, and a part of these radionuclides exists in the river suspension and considerable amounts of 106Ru, 137Cs and 144Ce are precipitated on the river bottom. It was observed on the decontamination rates (DR%) of radionuclides in the water works that the greater the content of the suspension increases, the higher DR become. The correlation of DR and S was shown by the following equation. [numerical formula] The coefficient a4 was 0.0462 for 137Cs in the Niitsu City water works, Agano River basin. During 1962 to 1969, DR in the three water works were observed as 50% for 106Ru, 48% for 144Ce, 31% for 137Cs, and 15% for 90Sr in average value.

Enteric bacterial metabolism of stream sediment eluates.

River bottom sediments, which were washed free of loosely associated chemical nutrients, were further eluted with phosphate buffer. Chemical analyses of the eluates indicated that 0.3 M buffer (pH 7.0) eluted hexose, protein, and ammonia nitrogen in concentrations 4–6 times that found in the free-flowing water. Respiration experiments showed that selected strains of Enterobacteriaceae, including pathogens, had the ability to metabolize these substrates. These studies indicate that bottom sediments can have a high adsorptive capacity and suggest that they can regulate basic nutrient concentration and eutrophication in situ.

The concentrations of lithium, potassium, rubidium and cesium in some western American rivers and marine sediments

Lithium, potassium, rubidium and cesium in river water, suspended matter, and bottom sediments have been measured by a flame photometric method in samples from three western American river systems; concentrations in four marine sediments are given for comparison.

Multiplication and growth of selected enteric bacteria in clear mountain stream water

Measurable multiplication and protein synthesis rates were observed for various environments approximating those conditions occurring in a cold mountain stream. An extract of river bottom sediments provided a better nutrient source for the organisms tested than did river water from sites above and below a sewage plant on two low nutrient control media. Concurrent field studies on the river, using dialysis sac-culture techniques, also showed periods of bacterial multiplication. These data suggest that the aquatic environment associated with a clear mountain stream not only can maintain populations of enteric bacteria but also can supply sufficient nutrients to initiate multiplication and de novo protein synthesis.

Sediment penetration with a short-pulse sonar

Abstract : A sonar with a short acoustic pulse and high peak power (0.1 to 0.5 ms, 108 db) has been adapted for shallow water bottom penetration by speeding up the pulse rate to 30 cps. Known as the Pinger Probe, it has evolved from the EG and G sonar Pinger for positioning deep-sea cameras and is a device especially designed to show objects submerged in the soft bottom sediments of rivers, harbors, bays and coast lines. It emits a short, relatively powerful acoustic pulse capable of penetrating certain sediments and reflecting from objects or layers of different densities as a return signal. Coupled with a high resolution Alden recorder, it has a detection capability for locating a variety of sediment layering and shallow buried objects. The increased pulse repetition rate provides much improved resolution.