ABSTRACT
Using the MS method, our laboratory has obtained profiles of 230Th and 232Th, in both dissolved and particulate forms, in the water column of Santa Monica Basin. A surface enrichment was observed for both dissolved 230Th and dissolved 232Th, strongly suggesting a terrestrial source for both long-lived Th isotopes. The concentration of dissolved 232Th dereased by a factor of q,4 from the surface (5.1x10-5 dpm/l) to 5 m off the bottom (1.4x10 5 dpm/l). The concentration levels, averaging 2.8x10-5 dpm/l, were comparable to most published data; but I tend to consider that the dissolved 252Th concentration in the SM basin, which is only '1,30 km
