The soil profile increments of 0 to 5,-5 to 10, 10 to 15, 15 to 25, 25 to 40, and 40 surveys, to so 60 cm are they can those developed easily be on previous compared with collected from Enewetak and Bikini Atolls. the LLNL Marshall bulk of data Islands previously We have found that a 40-cm depth encompasses most of the active root zone of the subsistence crops that we have sampled in the Northern Marshall Islands. A trench was dug with a backhoe or shovel radially from the trees to minimize root damage. After the sidewall of the trench was scraped to avoid any possible contamination from the digging process, collected samples were collected from the sidewall. from a surface area about 25 cm on a The O-to-5-cm sample was side. The area was expanded by about 10 cm on each side and cleared to a depth of 5 cm. then The upper surface (1 to 2 em) of this enlarged region (35 by 35 cm) was then cleared to ensure that neither surface soil nor soil from a preceding increment had fallen onto it. (i.-e., The next sample was then taken from the entire depth of the increment 5 to 10 cm) for an area of about 25 em= within the enlarged region. ‘This procedure was repeated until the final depth increment of 40 to 60 cm had | been collected. A total of approximately 500 to 900 g of soil was collected for each profile increment. Many soil profiles were collected at associated plant samples were taken. manner described above. sites around the islands where no These profiles were collected in the same While the sample profile sites are selected more or less randomly, it is advantageous to choose a relatively undisturbed site with litter and surface soil intact. MARINE SAMPLES Water Sampling Large-volume locations in cylindrical particulates. seawater each samples lagoon. fiber-cartridge Groundwater All liter) samples filter (well (56.5 into water) were 15-gal and were taken filtered plastic cistern from through barrels water to various a Il-p separate (rainwater from dwelling roofs) samples (56.5 liter) were collected whenever available at the atolls. The groundwater separate particulates. was filtered through 1- Cistern water was not filtered. and 0.4-y filters to All water samples and corresponding particulates (filters) were sent to LLNL for processing.