Table 1.

Variability in Pb concentration and isotopes during closed-system isotope exchange experiment.

name and timestep	206/207	206/207 2 s.e.a	208/207	208/207 2 s.e.a	[Pb] (pmol l−1)	SD for [Pb]b (pmol l−1)
Johor A unfiltered	1.1987	0.0001	2.5438	0.0001	373.4	5.4
Johor A T0 no spike	1.1998	0.0001	2.5239	0.0003	18.3	2.0
Johor A T0	1.1781	0.0001	2.5085	0.0003	25.4	1.4
Johor A T 3 h	1.1893	0.0002	2.5283	0.0004	32.7	0.5
Johor A T 5 h	1.1841	0.0005	2.5364	0.0013	27.1	2.4
Johor A T 24 h	1.1811	0.0003	2.5317	0.0004	21.1	1.5
Johor A T 47.5 h	1.1869	0.0002	2.5400	0.0006	20.9	1.0
Johor A T 7 days	1.1900	0.0002	2.5456	0.0004	35.2	0.5
Johor A T 23 days	1.1938	0.0005	2.4788	0.0009	33.9	2.0
Johor A T two months	1.1967	0.0001	2.5368	0.0003	33.0	3.7
Johor B T 0	1.1668	0.0002	2.5210	0.0004	47.8	1.9
Johor B T 2 h	1.1671	0.0002	2.5253	0.0004	45.9	1.6
Johor B T 21 h	1.1675	0.0002	2.5255	0.0006	43.9	1.1
Johor B T 44.5 h	1.1678	0.0003	2.5206	0.0006	47.4	1.3
Johor B T 7 days	1.1667	0.0002	2.5234	0.0008	c
Johor B T 23 days	1.1711	0.0003	2.4553	0.0008	36.0	1.8
Johor B T two months	1.1673	0.0004	2.5849	0.0005	36.8	2.3

^aThe 2 s.e. was twice of the normalized standard deviation associated with the internal counting statistics of the ICP-MS during the run. The external reproducibility was monitored by measuring an in house standard (BAB3 deg, calibrated with NBS981 standard reference material) in the beginning and the end of the day and in between every five samples.

^bEach seawater sample was measured at least three times and the s.d. was the standard deviation of the triplicates.

^cRan out of sample.