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A field study in the upper Coastal Plain of South Carolina was conducted to evaluate the impacts of several litter manipulations on carbon dioxide evolution from a longleaf pine (Pinus palustrisMill.) forest floor. These manipulations, which included prescribed burning, removal of the L‐layer material (red straw), and total litter (O1 and O2 horizons) removal, were compared with undisturbed control treatment using a static alkali absorption technique for CO2measurement. Though slight reductions were noted, the burning and removal of the L‐layer material had less effect on the evolution of CO2from the forest floor than total litter removal. Total litter removal, however, significantly reduced the average rate of CO2evolution by approximately 22% (p≤ 0.05). The amount of CO2evolved was sensitive to rainfall and air temperature, showing declines in periods of drought and cool temperature. However, on an annual basis, the air temperature was much more important than rainfall in estimating the CO2evolution. The burning treatment increased the pH and nitrogen concentrations of the litter and the soil pH at the 0 to 5‐cm depth. The calculated net annual respiration (CO2‐C production), exclusive of root metabolism, was approximately equivalent to 95% of the C input from litterfall deposited on the ground during this period, indicating that perhaps the accumulation of litter has reached a steady state condition.

The reduction of arsenate ion to arsenite ion by a variety of tissues was widely distributed, and not a property of any particular tissue. The nature of the reduction was investigated by using various chemical inducers and inhibitors and is believed to be chemical in nature.

Arsenite ion, as arsenic trichloride was extracted into benzene from strongly acidified tissue homogenates. Following this, arsenite was extracted from the benzene into water, made up in 1N HCl and analyzed polarographically. Arsenate ion, left in the homogenate after arsenite extraction is isolated in exactly the same way following treatment of the homogenate with cuprous ion to reduce arsenate to arsenite ion. Treatment of the acidified homogenate with cuprous ion prior to extraction gives a homogenate which is readily analyzed for total “inorganic” arsenic. The method was efficient to a maximum level of about 20 μg inorganic arsenic since at higher levels lower recoveries were found. Analysis of a variety of marine biological specimens, with levels of total arsenic up to 40.5 ppm, indicated little of this arsenic was present in an inorganic form. Post mortem reduction of arsenate to arsenite was found to occur rapidly in fish tissue.

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Field studies on the use of coated polyurethane foam plugs as indwelling water monitors and studies of the ability of such foams to quantitatively extract polychlorinated biphenyls, dieldrin and members of the DDT complex were carried out using waters of an industrial nature and agricultural nature. Recoveries of all spiked materials were generally in excess of 90%. Indwelling foams took from 24-48 hours to reach plateau values and from the levels of plateaus reached it is suggested that only the external surface of the porous plug is active. Use and reuse of plugs as well as extraction in the field is easily accomplished.