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1. The renal clearance of salicylate has been measured in two groups of patients undergoing treatment by alkaline diuresis for salicylate poisoning. One group received mannitol and sodium lactate, the other acetazolamide and sodium bicarbonate.2. The relationship between urine pH and salicylate clearance was found to be the same in both groups and similar to that shown at non-toxic concentrations in the blood by previous workers.3. The influence of the rate of urine flow on the relationship between salicylate clearance and urine pH was also shown to be similar to that found at non-toxic concentrations in the blood.Although alkaline diuresis is now widely accepted as the most effective method of hastening the renal excretion of salicylate, very little is known about its effect on the clearance of this substance in patients with salicylate poisoning. The observations that form the main basis of alkaline diuretic treatment were made at therapeutic blood concentrations in human volunteers (Macpherson, Milne & Evans, 1955;Gutman, Yu & Sirota, 1955) and in dogs (Weiner, Washington & Mudge, 1959). They revealed a linear relationship between log salicylate clearance and urine pH, with a fourfold increase in clearance for each pH unit. There was also a rise in clearance with increasing urine flow, though this effect was relatively small at high urine pH. These observations were consistent with what has become the accepted theory of the renal excretion of weak acids and bases (Milne, Scribner & Crawford, 1958).The present paper reports measurements of salicylate clearance in patients undergoing treatment for salicylate poisoning, at blood salicylate concentrations up to five times higher than those in the human volunteers studied by Macpherson et al. (1955). For obvious reasons, the conditions were neither as uniform nor as stable as in planned experiments. The observations are nevertheless noteworthy because they confirm the predicted relationship between salicylate clearance and pH, and because oftheir relevance to the treatment of salicylate poisoning.

An extensive study has been made of the faecal and urinary plutonium excretion from two subjects who sustained high levels of contamination on the uncut skin of the hand from accidental contact with acid plutonium solutions. In one case, where the contaminant was mixed plutonium isotopes in aqua regia and nitric acid, the measurements reported have covered 150 days. In the other case, excretion after contamination with a solution of plutonium in dilute hydrochloric acid containing EDTA and a detergent has been followed for 110 days. The excretion patterns show marked differences from the human experimental data published by LANGHAM, particularly in the high and variable amount of plutonium excreted in faeces relative to urine.The excretion data are supplemented in one case by a series of measurements on the levels of skin contamination, by exploratory body radioactivity measurements and by a few inconclusive blood plutonium analyses.Attempts have been made to estimate the body burdens in various ways. The wide variation of these estimates indicates the uncertainties in predicting body burden from excretion data. The present study gives no indication as to the major site of deposition of the plutonium.

The concentrations of some fission products in rain water falling on the catchment areas of three Thames tributaries are compared with the concentrations in river water over monthly periods. The fission products selected were SrBQ, SrQo, Cs13' and GelP4.A comparison of the concentrations in corresponding samples of rain and river water showed that natural decontamination factors were smallest for SrQo and greatest forThe Srso concentrations in river water appear to depend to some extent on the permeability of the subsoil in the catchment area, which suggests that surface run-off is an important source of contamination. The amount of Sr9o leaving each catchment area in the river is compared with the amount deposited. Normally less than 1 per cent leaves in the river, but in periods of heavy rain and high flow rates this may be considerably increased due to desorption from the soil and enhanced run-off.The effect on the Sr90 concentration in river water of (a) increased testing of nuclear weapons and (b) a reactor accident are discussed briefly.

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