Norman Cutshall

Manganese cycling in the Newport River estuary, North Carolina

Abstract Dissolved Mn was measured in the Newport River estuary, North Carolina, in October 1974, February 1975 and April 1975 by extraction on Chelex-100 resin and subsequent analysis by flameless atomic absorption spectrophotometry. Dissolved Mn concentrations at intermediate salinities were in excess of those predicted by conservative mixing of inflowing river and ocean water, with maxima between 4 and 14‰ salinity. Reduction and solubilization of Mn in bottom sediments in the upper estuary probably supplies much of the added dissolved Mn. Fixation of dissolved Mn on particles takes place in the lower estuary with subsequent upstream recycling. The export of dissolved Mn from the estuary in excess of that input by the river is probably balanced by continuous traction flows of river-derived bed sediment or pulse inputs of suspended sediment in storm runoff followed by partial solubilization.

Cesium-137 in Montana soils

Fallout 137Cs levels in soil were measured at 11 diverse sites throughout Montana. Concentrations in near-surface samples ranged from 20-200 mBq g-1 (0.51-5.41 pCi g-1). Most of the 137Cs was in the top 10 cm of soil. Deeper occurrences were attributed to disturbances by animals and to interstitial flow of small sediment particles within saturated soils. The areal concentrations ranged from 130-748 mBq cm-2 (3.6-20.2 pCi cm-2) and were highly correlated with annual precipitation.

Chromium-51 in Sea Water: Chemistry

Chromium-SI introduced into the Pacific Ocean from the Columbia River remains in the hexavalent state. Analysis of this radionuclide in sea water by hydroxide coprecipitation with iron is best accomplished if the chromium-51 is first reduced to the trivalent state.

Chromium-51 as a Radioactive Tracer of Columbia River Water at Sea.

The plume of the Columbia River was followed 350 kilometers to sea by measurement of its chromium-51 content. This radioactive tag, introduced into the river by nuclear reactors at Hanford, Washington, promises to provide a useful oceanographic tool for determining rates of transport and mixing, and for identifying plume waters in the presence of other sources of fresh water.

Calibration of a portable intrinsic Ge gamma-ray detector using point sources and testing for field applications

A simple procedure using point sources is described for the calibration of portable high-resolution gamma-ray detectors used in field surveys. The point source data are fitted by empirical equations that are used to calculate efficiency for field applications. Two models for the distribution of radionuclides are treated: a thin surface-film model and a vertically homogeneous model. The success of the procedure has been demonstrated by field applications in plots where the levels of contamination are known.

Radioactivity: Detection of Gamma-Ray Emission in Sediments in situ

A probe for measuring emission of γ-rays in sediments in situ in water depths to about 35 meters was used to measure radioactivity in the Columbia River estuary and Oregon coastal areas. This technique offers some advantage over methods in which sediment samples are collected at sea and returned to the laboratory for radioanalysis.