Washington State Dept. of Ecology 3/27/2025

Page 2 of 8 F. Groundwater Level Monitoring Procedures 1) Schedule monitoring event a) Groundwater monitoring should be conducted concurrently with soil sampling, in addition to other monitoring events scheduled by the Biosolids Manager. b) Groundwater monitoring will be done at regular intervals in the spring, as decided by the Biosolids Manager, to track groundwater levels in advance of biosolids application. 2) Travel to each well and record the groundwater depth at that site on the site map. 3) If groundwater levels in the East Field are within three feet from the surface, complete the following additional steps: a) Using the post hole digger, dig one additional hole at least two feet deep in the Southwest corner of the East Field (within the areas marked 34 or 39 on the soil map in Appendix C). Allow 5-10 minutes to fill with water and record this location and water depth, if any, on the map. 4) Report results to Biosolids Manager. G. Soil Sampling Procedures 1) Schedule sampling event a) Biosolids Program Manager will schedule sampling event with IPT and EEL. i) Sampling is ideal after a period of dry weather when water table is more than a foot down to minimize impacts of surface water on sampling. b) Obtain Chain of Custody from EEL. c) Prelog samples and obtain sample labels. d) Request soil pH analysis upon return to EEL (must be completed on collection day). 2) Prepare equipment and supplies. 3) Collect soil samples. a) Find sample location from the map. b) Remove organic matter (grass, roots, sticks, etc.) surrounding sample site. c) Dig a hole deeper than the organic layer (about one foot deep). i) Skip sample site if water table is less than one foot from surface and make note on the map. d) Collect consistently sized samples from each site. e) Remove any remaining organic material (roots, leaves, worms, etc.). f) Place each sample in a separate bucket. i) When bucket becomes too heavy to carry, store bucket in sample vehicle and use another bucket to collect remaining samples. g) Mark off sample location on map after collecting sample or note reason if skipped. h) Once all 25 sites for a field have been sampled, composite the soil samples in each bucket by mixing with bucket mixer. Make sure large chunks are broken up. i) Fill six jars with sample for each field (three for Composite 1, three for Composite 2). 4) Deliver samples to EEL. a) Deliver COC to EEL. b) Confirm soil pH analysis will be completed same day. 5) Follow-up with Biosolids Program Manager. a) Notify Biosolids Program Manager that sampling was completed, send marked map and copy of CoC, and describe site conditions and any other sampling notes. 6) Clean equipment a) Clean equipment and return to storage.