SITE INFORMATION AND CORRESPONDENCE

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transferred to a one-liter glass bottle with a Teflon septum. The sample must then be preserved, tagged and chilled as above. G. Sample Collection - Sediment Often sediment samples from the bottom of a sump are collected using a beaker attached to a pond sampler. A stainless steel lab scoop is generally used to transfer the sediment from the beaker to the required container. Sediment samples should be placed in an 8-oz. wide-mouthed glass jar. The jar should be completely filled so that no headspace is present. After being taped and labeled, the sample should be placed immediately in an ice chest and kept cold (4°C) for delivery to the laboratory. Care should be taken throughout to avoid contamination of both the inside and outside of the jar and its contents. H. Sample Collection - Soil The bore hole can be made with a continuous flight or hollow stem auger, rotary core drill or other drilling method. It is recommended that core sampling equipment avoid the use of drilling fluids since these greatly increase the potential for sample contamination. Soil sampling kits are commercially available that can be used at relatively shallow depths to both drill the bore hole and collect a soil core. These units contain augers, coring tubes and sufficient drill rod extensions to sample up to depths of twenty-five feet. The most common procedures for collecting soil samples use a thin-wall steel tube (core barrel), fitted with a brass liner, which is forced into the undisturbed soil at the bottom of the bore hole. This is sometimes referred to as drive sampling. Core barrels are generally from one inch to three inches in diameter and 12 to 24 inches long. When the core barrel is retrieved, friction will usually retain the sample inside the barrel in most unsaturated materials. Samples should be taken at locations where the potential for a high degree of contarri at= exists (suspected worst-case locations) such as elbows, joints in pipe lbw..; clmifrers, floor draatg toVa and wells Several depth boruW should be planned to be sampled for chemical analysis Sample baervals wig vary, but iii general should be taken between one and two feet beneath the excavation or the bottom of the septic tanlr, cesspool, well, pipe lure or floor drain surface and then every five feet to the water table, or until five feet past the last suspected contmnbuidom Upon retrieval from the borehole, the sample liners should be removed and placed on clean plastic. Using cuttings or corings, the borehole should be logged to the full depth by an on-site geologist according to the Unified Soil Classification System. 25