Attachment 2: SOIL SAMPLE COLLECTION

This section describes the sampling and analytical protocols to be used to obtain and characterize representative soil samples. Samples will be collected from the surface and subsurface soil in accordance with the Field Protocol. Samples can be analyzed for:

Volatile Organic Compounds (VOC)
Semi-Volatile Organic Compounds (SVOC)
Total Petroleum Hydrocarbons (TPH)
Biomarkers

A separate method for collecting samples for VOC analysis is described, as well as a more accurate method for collecting surface and subsurface soil samples. The equipment and procedures for collecting and preparing samples for laboratory analyses are described below.


Sampling Equipment

A soil auger bucket and a thin-walled split core sampler tube fitted with a plastic liner are recommended for the collection of the soil samples. The combination of the auger and the sampler tube will: 1) allow the most precise control over the depth of the sample collection, 2) ensure that no cross-contamination occurs between sample depths, 3) minimize contact with the atmosphere (important for sampling volatile organic compounds), and 4) provide a sufficient volume of soil for chemical analyses. The use of a tube sampler alone involves some uncertainty as to the depth being sampled, as the presence of a rock or compression of the soil during sampling can effect the sample recovery. The use of a bucket auger alone can result in the loss of VOCs.

The sampling tools are described below:

Soil Auger Bucket - A stainless-steel soil auger bucket (AMS Model 77545) is used to advance the borehole ahead of the tube sampler. The auger bucket is comprised of a 6 1\2 inch long cylinder which measures 3 1\4 inches in diameter and is equipped with a cutting edge. Note that several types of cutting edges are available for boring in sandy or clay loam soils, dry and loose sand, or in wet clays. The auger bucket is threaded to a rod which is equipped with a cross handle.

Split Core Sampler Tube - A stainless-steel core sampler (AMS Model 77801) is used to collect the analytical samples. The core sampler measures 2 inches in diameter and is 12 inches in length. The core sampler splits into two sections when opened enabling the sampler to easily access a plastic liner which is fitted into the core prior to sampling. The core sampler is driven to the correct depth in the borehole with an extendible compact slide hammer (AMS Model 77454).


Soil Sampling Methods

Surface and subsurface soils will be sampled. The following steps for collecting soil samples include a recently-devised technique for ensuring accurate recovery of VOCs. This technique (SW-846 Method 5035) is required in some states, and supersedes the direct collection of a soil sample and placement in a glass jar fitted with a teflon-lined cap. This procedure has been designed to prevent losses of VOCs due to volatilization and biodegradation prior to receipt at the laboratory, and laboratory tests indicate that concentrations of VOCs could be significantly greater than determined under previous protocol (i.e., reduced loss of VOCs). If VOCs are not going to be analyzed, then these steps can be skipped.

All samples to be used for analyses other than VOCs will be composite samples, which involves placing each subsample collected from within a treatment plot into a stainless steel bowl and mixing to create the composite.

Surface Soil Sample Collection

Prior to sampling, remove all surface materials that are not to be included in the sample such as rocks, twigs, and leaves. Pass through 1/4" screen.

The split core sampler is fitted with a plastic liner and driven to the desired surface soil sampling depth.

The core sampler is retrieved from the borehole, the split barrels opened, and the plastic liner cut with a utility knife.

If sampling for VOCs (optional):

A disposable plastic spatula is used to scrape soil directly into a laboratory supplied, non-preserved container specific for moisture determination (according to Method 5035).

Fill three sample syringes (EnCore TM Sampler - Lancaster Laboratory) with soil. Note that Method 5035 requires a total of three syringes for each sample. It is the intent of the sampling plan to space the collection of soil for the syringe samples evenly throughout the depth interval of interest.

The remaining soil in the liner is placed into a stainless steel bowl for the creation of composite samples. When all of the subsamples of the composite have been placed within the bowl, the contents of the bowl are throughly mixed with a stainless steel trowel or spoon. The soil is placed into laboratory supplied glass jars specific for the analysis of SVOCs, TPH, and biomarkers.

Subsurface Soil Sample Collection

The lower depth interval sample is collected from within the same borehole as the surface soil sample, using the following procedures. Note that the sampling tools should be throughly decontaminated (using procedures described below) prior to advancing the borehole for the deeper sample to ensure that no cross-contamination occurs between the samples.

The soil auger bucket is used to advance a wider diameter borehole to the top of the subsurface soil sample depth increment, slowly and carefully removing the auger to avoid brushing loose soil material back down the borehole.

The core sampler is driven to the desired subsurface soil sample depth, is retrieved from the borehole, the split barrels opened, and the plastic liner cut with a utility knife.

If sampling for VOCs (optional):

A disposable plastic spatula is used to scrape soil directly into a laboratory supplied, non-preserved container specific for moisture determination (according to Method 5035).

Fill three sample syringes with soil (see the instructions for the surface soil sample collection).

The remaining soil in the liner is placed into a stainless steel bowl for the creation of composite samples. When all of the subsamples of the composite have been placed within the bowl, the contents of the bowl are throughly mixed with a stainless steel trowel or spoon. The soil is placed into laboratory supplied glass jars specific for the analysis of SVOCs, TPH, and biomarkers.

Sample Identification

Samples collected for laboratory analysis are identified by using standard sample labels which are attached to the sample containers. The following information should be included on the sample labels (using waterproof ink):

project name;
field identification and depth interval of the sample (such as A1(0-18) or A1(18-24));
date and time of sample collection;
designation of a sample as a grab (VOC) or composite (SVOC, TPH, and biomarkers);
the signature of the sampler;
the sample preservation used; and
the general type of analyses to be performed.


Chain-of-Custody Record

The field chain-of-custody record is used to record custody of all samples collected and maintained by the field personnel. The record transfers custody of the samples from the field personnel to another person, to the laboratory or to other organizations (such as Federal Express). To simplify the chain-of-custody record, as few people as possible should have custody of the samples. The record also serves as a sample logging mechanism for the laboratory sample custodian. The following information must be supplied on the field chain-of-custody record which accompanies the samples to the laboratory:

the project name;
the signature of all samplers must be in the designated signature block;
the sample designation;
sample date;
time of sample collection;
whether the sample was a grab or composite sample;
any air bill number used to ship the samples; and
any remarks or any other pertinent information to be used by the laboratory, such as turn-around time or quality control specifications.

Packaging and Shipment of Samples

Proper packaging and shipment of samples will minimize the potential for sample breakage, leakage or cross contamination. When preparing a cooler for shipment, all contents are to be removed and the samples inventoried and checked to ensure that information is entered correctly on the chain-of-custody form. Each sample jar should be wrapped with protective material (e.g. bubble wrap matting) to prevent breakage. Each sample jar should be packaged in an upright condition. All sample jar caps should be checked during this time and tightened if needed. Additional packaging material such as bubble wrap or Styrofoam pellets should be spread throughout the voids between the sample bottles.

To ensure that samples are cooled to the correct temperature (4 degrees C), ice is placed in heavy duty zip-lock type bags, which are distributed over the top of the samples. Additional packing material should then be placed to fill the balance of the cooler or container.

To ensure that the coolers are not tampered with prior to receipt at the laboratory, chain-of-custody tape (signed and dated) should be placed at two different locations (front and back) on the cooler or container lid and overlap the tape with transparent packaging tape. Packaging tape should encircle each end of the cooler at the hinges.

Sample shipment should occur via an overnight express service that can guarantee 24 hour delivery. All shipment records, as provided by the shipper, should be retained for the project files.


Quality Control Quality Assurance Samples

Quality control samples should be collected during the field sampling to evaluate the field and laboratory variability. These samples include:

Duplicate Samples - Duplicate samples are taken from soil collected from a common source to determine the variability of a given constituent following laboratory analysis. Generally, one duplicate sample should be collected and submitted to the laboratory for every 20 soil samples (check to see the requirements in your state).

Trip Blanks - Trip blanks are samples which are prepared at the laboratory and are stored with the soil samples throughout the sampling event. The samples are used to determine if soil samples were contaminated during storage or transportation back to the laboratory. Note that trip blanks should be included in each sample cooler containing samples sent to the laboratory for VOC analysis.

Equipment Field Blanks - Equipment blanks are collected using laboratory-provided organic-free water which has been run over the decontaminated soil sampling equipment. These samples are used to determine the efficiency of cleaning procedures for soil sampling equipment.

Matrix Spike (MS) and Matrix Spike Duplicate (MSD) Samples - These analyses are run to evaluate the performance of the laboratory. Note that it is not necessary to include extra soil sample volume for these analyses, as the MS and MSD samples are prepared in the laboratory. MS and MSD samples should be analyzed at a frequency of one sample for every 20 soil samples.


Decontamination

All sampling equipment will be decontaminated prior to use, between the two sampling depth intervals and between each sample collection point. Waste products produced by the decontamination procedures such as rinse liquids, solids, paper towels, gloves, etc. will be collected and disposed of properly. The following steps will be used to decontaminate all soil sampling equipment:

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