Flegal Lab Processing:
For every sample, standard, blank and reference, we integrate an elution peak. We used a seawater standard calibration curve for lead. We subtracted a process blank from every sample. We checked that reference samples analyzed and processed in the same way resulted in reasonable values. NOTE: concentration values are in parts per billion units.

BCO-DMO Processing:
- added conventional header with dataset name, PI name, version date
- renamed parameter names to GEOTRACES standard naming conventions
- edited Pb conc. values from 14 decimal precision to 2 decimal precision.
- split GeoFish samples into a separate column from GO-FLO bottle samples.
- sample values were place in station order for all sample numbers.
- nominal depth for GeoFish samples was edited from 'surface' to 3.5 meters
- removed one duplicate sample (8346) entered as both a bottle and GeoFish sample (master event and GeoFish cast logs confirmed the sample to be from GeoFish, therefore the bottle entry was deleted).
- added columns by joining the submitted data with an Events Master file (see Additional GEOTRACES Processing).

Additional GEOTRACES Processing:
As was done for the GEOTRACES-NAT data, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters:

cruise_id, EXPOCODE,SECT_ID, STNNBR, CASTNO, GEOTRC_EVENTNO, GEOTRC_SAMPNO, GEOTRC_INSTR, SAMPNO, GF_NO, BTLNBR, BTLNBR_FLAG_W, DATE_START_EVENT, TIME_START_EVENT, ISO_DATETIME_UTC_START_EVENT, EVENT_LAT, EVENT_LON, DEPTH_MIN, DEPTH_MAX, BTL_DATE, BTL_TIME, BTL_ISO_DATETIME_UTC, BTL_LAT, BTL_LON, ODF_CTDPRS, SMDEPTH, FMDEPTH, BTMDEPTH, CTDPRS, CTDDEPTH.

This added information will facilitate subsequent analysis and inter comparison of the datasets.

Bottle parameters in the master file were taken from the GT-C_Bottle and ODF_Bottle datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the TN303 Event Log (version 30 Oct 2014). Where applicable, pump information was taken from the PUMP_Nuts_Sals dataset.

A standardized BCO-DMO method (called "join") was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.

If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the names of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.

See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.