Cation exchange capacity of suspended material from coastal sea water off central California

The cation exchange capacity (CEC) of suspended particles (> 0.5 μ) in sea water is measured by a described methylene blue (MB) absorption method which has the following characteristics: sample volume: minimum of 100 ml sea water; time of measurement: about 10 min; useful range: 0.1 – 10.0 μe/δ precision: ± 0.05 μe/ δ at 0.7 μe/ delta;; accuracy: function of organics and clay types. Test of the MB method with sea water samples from the central California off-shore show background values of about 1 μe/delta; with higher values up to 5 μe/delta; in the vicinity of stream discharge.