In General;
When collecting samples of concentrated wastes for laboratory analyses, field personnel are required to screen the waste materials to ensure safe handling and transportation of the samples.
Safety procedures, sampling and screening methods used to collect the samples must comply with those procedures/methods described in this protocol.
It should be noted that waste samples should not be preserved because of the potential for an inadvertent chemical reaction with the preservative. Additionally, concentrated waste samples are not required to be cooled to 4°C.
After samples have been collected and containerized, the outside of the sample containers should be cleaned with water, paper towels and/or oil wipes to remove any spilled material from the exterior of the container. It should be noted that each sample container should be labeled.
Field investigators will use knowledge gained of site practices and processes, labels and marking on waste containers, field screening results and personal observations made during their investigation to determine the hazard potential of a sample.
Samples considered to be hazardous by the field investigators or detected to have strong chemical odours will be placed in secondary containment for transport to the SESD laboratory and for subsequent handling upon arrival. The bagged samples will be placed in a plastic pail and sealed with a tight fitting lid.
Read Also : Health Impacts of Solid Wastes
The project number for the sampling investigation and the specific sample station number will be marked on the secondary container in indelible ink. A standard SESD hazard Communication Label will be affixed to the side of the secondary container.
The appropriate hazard(s) for the sample (health, flammability, and/or reactivity) will be indicated with an “X.” Additionally, an “X” will be placed in the “protective equipment” section of the label if protective equipment was required for collection of the sample.
All secondary containing pails will be secured in the vehicles while transporting the samples from the field to the laboratory for analyses. In addition, each pail should indicate when protective equipment is recommended to handle the actual waste sample material.
Particle Size Reduction
Particle size reduction of waste samples is periodically required in order to complete an analytical scan or the toxicity characteristic leaching procedure (TCLP) test. samples that may require particle size reduction include slag, bricks, glass/mirror cullet, wire, etc. method 1311 (TCLP) states “particle size reduction is required, unless the solid has a surface area per gram of material equal to or greater than 3.1 cm2, or is smaller than 1 cm in its narrowest dimension (i.e., capable of passing through a 9.5 mm (0.375 inch) standard sieve).
If the surface area is smaller or the particle size larger than described above, prepare the solid portion of the waste for extraction by crushing, cutting or grinding the waste to a surface area or particle size as described above” the method also states that the surface criteria are meant for filamentous (paper, cloth, etc.) waste materials, and that “actual measurement of the surface area is not required, nor is it recommended.” also, the loss of volatile organic compounds could be significant during particle size reduction.
Waste samples that require particle size reduction are often too large for standard sample containers. If this is the case, the sample should be secured in a clean plastic bag and processed using normal chain-of-custody procedures.
Note that the sample labels or tags that will be required for the various containers should be prepared in the field and either inserted into or attached to the sample bag.
Because of the difficulty in conducting particle size reduction, it may be completed at a special center established for it at country level. The following procedure may be used for crushing and/or grinding a solid sample:
Remove the entire sample, including any fines that are contained in the plastic bag and place them on the standard cleaned stainless steel pan or cover the sample material with clean plastic.
Using a clean hammer, carefully crush or grind the solid material (safety glasses are required), attempting to minimize the loss of any material from the pan. Some materials may require vigorous striking by the hammer, followed by crushing or grinding. The material may be subject to crushing/grinding rather than striking.
Continue crushing/grinding the solid material until the sample size approximates 0.375 inch. Attempt to minimize the creation of fines that are significantly smaller than 0.375 inch in diameter.
Pass the material through a clean 0.375-inch sieve into a glass pan.
Continue this process until sufficient sample is obtained. Thoroughly mix the sample as described in the SESD operating procedure for soil sampling (SESDPROC-300). Transfer the contents of the glass pan into the appropriate containers.
Attach the previously prepared labels/tags and submit for analyses.
Laboratory Selection
Prior to submitting samples to a laboratory for analysis, the certification status of the laboratory must be determined. Laboratories submitting analytical data to the authority must hold current certification where applicable under the regulations governing the certification of laboratories and environmental measurements and/or under other relevant bodies. The offices concerned with quality assurance offers certification in the following categories:
Drinking water program
Oil spill and detection program
Solid and hazardous waste programs etc.
The government certification program requires certification for the “analyses immediately” parameters under the safe drinking water, water pollution, and the solid and hazardous Water programs. Certification for those parameters can be obtained from the offices responsible with quality assurance.
Additionally, immunoassay methods that are considered laboratory or field methods require certification under the solid and hazardous waste program. Regardless of whether a company or organization is or is not a laboratory, certification must be obtained. This includes but is not limited to responsible parties, contractors and facilities.
Quality Assurance Considerations
Quality assurance measures must be associated with each sampling and analysis event as an additional measure of control to assure that the sample delivered to the laboratory for analysis is representative of site conditions.
The sampling plan should outline how the representative quality of the samples will be assured. This will include, but not be limited to: data quality objectives, laboratory SOPs, field SOPs, sample bottle preparation, equipment decontamination, trip blanks, field blanks, duplicates, split samples, performance evaluation samples, sample preservation and handling, chain of custody, analysis request, analytical methods, parameters, and deliverables.
Quality Assessments
The sample collection process should be coordinated with the laboratory so that analysts know how many samples will be arriving, the approximate time of their arrival and the analyses that are to be carried out, and can thus have appropriate quantities of reagents/chemicals prepared.
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It is good practice to prepare a checklist such as the one on below, so that nothing is missing or forgotten before a sampling expedition is undertaken. Many of the items in the list are self-explanatory.
Personnel who will collect water, biota or sediment samples must be fully trained in both sampling techniques and field test procedures. They should also be aware of the objectives of the monitoring programme since these will have some influence on the sampling procedures.
Obtaining a sample that is fully representative of the whole site is difficult and the collection and handling of samples are also frequent sources of error (often greater errors than those arising during analysis).
Thus the choice of a representative sampling point and the use of appropriate sampling techniques are of fundamental importance.