Battery-operated pump In-line conductivity meter T-um filter Tygon tubing 0,4-um filter Ground level Unfiltered sample valve M4 “—Water level 15-gal drum for radionuclide samples or one-litre containers for stable-element and nutrient samples Fig. 2. Diagram of the pump arrangement for collection of groundwater samples. monitored during pumping by channel- analysis of chlorinity and other ing the water through an inline con- constituents. ductivity meter. passed O.4-\im) The water then through two filters In an experiment we designed (l-lim and follow the chemical and radiological changes in the water resulting from to remove suspended particu- late material; these filters were continuous pumping at a constant subsequently analyzed for radio- rate, groundwater at HFH 1] was nuclide pumped out continuously over an 8-hr content. collected The filtrate was smaller period; a total of 3200 litres was for radionuclide analysis in 15-gal black "“Deldrum" volumes were 1 containers; collected removed We 663 from the reservoir. Con- ductivity was monitored throughout for -5- eee to