The synthesis of dithiocacodylate complexes of the metals chromium(111), indium(111), manganese(11), cobalt(11), nicke1(11),� zinc(11), and copper(1) is described. The compounds can be prepared either from sodium dithiocacodylate Na[S2As(CH3)2] or by passing hydrogen sulphide through a methanolic solution of the metal cacodylate in the presence of hydrogen chloride. The infrared spectra in the region 4000-40 cm-1 of the new compounds have been recorded and assigned by a comparison with the spectra of several compounds which are closely related. The arsenic-sulphur and metal-sulphur stretching frequencies occur in the region of 450 cm-1 and 260-340 cm-1, respectively.

The optical spectra of U + and U + doped into hafnon (HfSi04) and thorite (ThSi04) are reported. However, no significant information was obtained on the validity of a previous crystal-field fit of the absorption spectrum of U'+ doped into zircon (ZrSi04). New experiments confirm the interpretation of Judd and Runciman of the Zeeman behavior of zircon:U'+.

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A crystal-field calculation has been made for the energy levels of an ion with an f' configuration in a D,"crystal field, appropriate to U'+ in zircon, ZrSiO". A previous analysis is found to be incorrect.The present analysis, using ten parameters, gives an energy-level fit which has a standard deviation of 112 cm ' relative to 30 observed levels. This fit is comparable to those obtained by other workers for U'+ in octahedral and tetrahedral symmetries. Zeeman experiments and magnetic-circular-dichroism measurements have yielded g values for a number of the cr-polarized absorption lines. The values of the parameters for the best fit are (in units of cm ):

No seasonal variations were found in the concentrations of Zn, Cd, Cu, K, Ca, Mg and Na in the kelp E. radiata collected from the marine-dominated Port Hacking estuary on the east coast of Australia. Concentrations of Fe and Mn were about 60% higher in late summer. The relative distributions of all metals between different kelp tissues, however, showed no seasonal variation. Concentration factors (dry weight basis) for trace metals ranged from 2600 for Cu to 68 000 for Fe. With high biomasses common in macroalgal ecosystems, a large proportion of the non-sediment- bound trace metals can be associated with the macroalgae, which therefore act as substantial buffers for these elements. Metal concentration factors (Y, wet wt basis) were related to oceanic residence times (τ) by the equation log Y = -0.69 logτ + 5.4. The distribution of the aikaii and akaline earth metais (K, Ca, Mg and Na) was relativeiy uniform throughout the various kelp tissues. However, concentrations of Fe, Mn, Zn and Cd were significantly higher in the older extremities (holdfast and eroding tip) than in the meristematic region. Although the holdfast also had higher levels of Cu than the meristem, levels were lower in the eroding tip. The results suggest either a slow net intracellular accumulation of metals with time or an increase in potential metal- binding sites as the extremities senesce. Translocation and elimination of surplus metals through the eroding tip or holdfast was thought not to be important in E. radiata as metal concentrations did not differ between live and dead haptera of the holdfast. Likewise, storage of metals in either the holdfast or eroding tip was considered unlikely because of the constant relative tissue distribution throughout the year and lack of metal mobilization during periods of growth. Pretreatment of kelp tissue with an EDTA wash released about 90% of the total Zn and Cd, 25% of the Cu and 7% of the Fe, suggesting that a large proportion of the total kelp Zn and Cd is associated with the apparent free space (AFS). With rapid exchange between seawater and the AFS, E. radiata is therefore not generally useful as a sentinel accumulator species in pollution studies for assessing long term integrated changes of metals in the water column.