| Summary: | A method has been developed for the determination of dissolved Mn and Fein open ocean waters in which the metals are chelated by a mixed dithiocarbamate reagent, solvent extracted into Freon TF (1,1,2-trichloro-1,2,2trifluoroethane), and back extracted into a small volume of dilute nitric acid. The metals were determined by graphite furnace atomic absorption spectrophotometry. The technique is also applicable to the determination of Cd, Co, Cu, Ni, Pb and Zn. Procedures were adopted or developed to control adventitious and systematic contamination during analysis and sample handling. Dissolved Cd and Mn were determined in samples taken at 13 stations in the equatorial and North Atlantic Ocean using the developed technique. Attempts to measure dissolved iron were negated by contamination. Dissolved Cd was highly correlated with dissolved phosphate at all stations. The overall regression equation for the whole data set (n=186) was Cd(nmol/l)=0.03+0.25P (umol/1), r=0.942. Dissolved Mn concentrations were highest in thee surface mixed layer (1 .26-3.17 nmol/l); there was a rapid decrease to about 0.25 nmolyl in the deep water. The coincidence of high atmospheric dust loadings and high surface dissolved Mn suggests that inputs of this element may be principally aeolian in this region. Small maxima of dissolved Mn superimposed on the general distribution may be caused by in situ biological and inorganic processes. The concentrations of dissolved Mn and Cd in Mediterranean Outflow Water were not elevated relative to eastern North Atlantic Ocean waters. Dissolved Al and As were determined in waters from the Cape Basin area of the South Atlantic Ocean. Mean concentrations of inorganic As above and below 110 m were 19.9 and 21.1 nmol/l respectively. Dissolved Al data showed considerable scatter, probably reflecting analytical and sampling inadequacies, with most concentrations in the range 4-15 nmbl/l. An analytical technique for the determination of dissolved Cd, Cu, Ni and Zn in estuarine and coastal waters was ...
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