COMPLIANCE INFO_2023 - Laserfiche WebLink

Home Browse Search

DIRECT PUSH SAMPLING PROCEDURES Soil Sample Collection Under the supervision of a geologist or engineer, the exploratory borings are advanced using a truck- mounted direct-push rig. A pilot assembly is driven and/or hydraulically pushed to the desired sample depth. When the desired sample depth is reached, the tip is released and the sample barrel is advanced. Typically, sampling is conducted at about 5-foot intervals. The sampler consists of an outer barrel in which a set of thin sleeves can be inserted. These sleeves are generally brass or stainless steel. The sample barrel is about 18 inches long and usually holds no less than three sleeves. The sample barrel is pushed and/or driven into the formation thereby filling all of the sleeves with soil. This method allows for collection of a relatively undisturbed soil sample and minimizing the introduction of overburden soil by a drilling process. After retrieving and dismantling the sampler, all the thin tube rings are removed. The bottom ring is immediately sealed for laboratory analysis by covering both ends with teflon sheeting, plastic caps and securing the caps with tape. If some of the soil in the bottom ring has fallen out or appears to have been disturbed during the recovery operation, the second to the last ring will be used. This ring is labeled and placed in an ice chest for cold storage pending transportation to a state-certified laboratory. This packaging protocol is designed to prevent loss of volatile compounds from the soil sample, and to prevent any cross contamination. Standard chain-of-custody procedures are followed for all samples. Soil from the second ring is used for field analysis of possible hydrocarbon contamination. The sample is either removed from the ring and placed in a self sealing plastic bag to prevent the release of volatile compounds that may be present or a portion of the sample removed from the ring and both ends of the ring capped. A head-space measurement is collected by breaking the seal of the plastic bag or ring end cap just enough to insert a sample probe of the hydrocarbon detector. The highest reading is recorded on the boring log. Soil in the uppermost ring is discarded as borehole slough. The soil from the second ring as well as surface cuttings are examined to complete the field descriptions. This data includes a written soil description using the Unified Soil Classification System, any noticeable odors and any unique staining or contamination. Also noted are unusual drilling conditions, equipment malfunctions or other observations of field conditions for future reference. All data are recorded on the boring logs. Groundwater Sampling Procedures