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The OLQ Chemistry Section provides technical support for remediation, permitting, and compliance programs for the Office of Land Quality. Technical assistance is available for environmental consultants, laboratories, and the general public.
Should soil analytical results be reported on a dry or wet weight basis?
All soil analytical results should be reported on a dry weight basis. Dry weight results are necessary because dry weight is an integral part of the soil-groundwater partitioning model, which is utilized in the calculation of the RISC Closure Levels. Since dry soil bulk density is part of the partitioning equation, all soil sample results need to be reported on a dry weight basis. The laboratory should run EPA water method 1684 to determine the Percent Moisture of each sample. The lab will then recalculate the sample result based on the dry weight by using the Percent Moisture result.
Should a Flame Ionization Detector (FID) or a Photo-Ionization Detector (PID) be used for field screening?
Either one can be used when screening for organic compounds. A PID can be used for those compounds with an Ionization Energy (IE) that is less than the PID's lamp voltage. Typically, a PID can be used for gasoline or chlorinated products. An FID should be used when the investigative compounds are not known or the compounds have higher IEs than the PID lamp. Typically, an FID is used for diesel, and weathered or heavy petroleum products.
Does method 5035 need to be used to sample soils for VOCs?
The IDEM recommends using SW-846 Method 5035 A, Appendix A, for sampling soils for Volatile Organic Compounds (VOCs). The traditional method of soil collection using four ounce jars has been shown to cause significant losses of VOCs during sample handling and storage. Further guidance on Method 5035 entitled "Supplemental Guidance for Sampling Soil and Waste Samples for Volatile Organic Compounds (VOCs) [PDF]" has been developed by OLQ.
Can peristaltic pumps be used to sample ground water?
Peristaltic pumps may be used to sample most ground water parameters such as metals or semi-volatile organics. They may also be used to purge wells (assuming the depth to ground water is not too deep for the pump). They are problematic, however, for volatile organic compounds (VOCs). Peristaltic pumps draw a vacuum and agitate the sample which affects VOC concentrations adversely and may bias the results. If the Data Quality Objective (DQO) of the project is not concerned with accuracy (e.g., you expect VOC concentrations to be high), peristaltic pumps may be appropriate. Utilizing a low flow or micropurge sampling method may improve recovery of volatiles. Contact the site Chemist for site specific options.
Should samples be filtered for the analysis of metals in ground water?
Over the years, there has been quite a debate on this issue. The IDEM has determined that ground water samples should not be filtered for metals analysis if the samples are to be used for remediation purposes. The IDEM Nonrule Policy Sampling and Analysis of Ground Water for Metals at Remediation Sites (Waste-0057-NPD, available on the IDEM Nonrule Policies page) has been written to address this issue. This guidance provides background information for using unfiltered ground water sampling for metals at remediation sites and outlines the ground water sampling methods for water supply wells, monitoring wells and boreholes. This guidance does not apply to those sites in the Solid Waste Permits or Hazardous Waste Permits programs.
How do I meet the holding times for hexavalent Chromium (Cr+6) in water samples?
The normal holding time for hexavalent chromium in water samples is 24 hours. The holding time can be increased to 30 days if the water sample is preserved with sodium hydroxide.
How much time do I have to get my samples to the laboratory?
It is recommended that samplers ship samples to the laboratory on the same day that they are collected, or as soon as possible thereafter. Note that some analytical parameters have very short holding times (See the analytical method for maximum holding time). Holding times are the maximum lengths of time that samples may be held from time of collection to time of preparation and/or analysis in the laboratory and still be considered valid.
Why does IDEM need to see all the QA/QC data?
The analytical methods require certain quality control samples and tests to document the precision and accuracy of each analysis. Each element in a complete QA/QC program is designed to give a specific piece of information about the results. There are many different items that can affect the accuracy and precision. Some of those are within a laboratory's control and some are not. The QA/QC data helps identify the accuracy and precision of the results; it helps identify matrix issues or lab problems during the analysis; and it allows IDEM to determine the quality of the data.
The project's Data Quality Objectives (DQOs) set the level of data quality needed for that project. Different projects may need different levels of data quality. When determining the nature and extent of contaminants at a site and for determining if closure has been achieved, high levels of data quality are needed. The quality of the data must be known to have confidence that it meets the closure levels, especially for risk based closure levels where some contaminants may be left in place. The QA/QC documentation requested by the Office of Land Quality is identified in Chapter 3 of the Remediation Closure Guide [PDF].
How much QA/QC do you need?
Data quality is meaningful only as it relates to the intended use of the data (i.e., the DQOs). Table 3-A includes elements that IDEM has determined are necessary to support two types of DQOs. For example, every element in Table 3-A (where appropriate to the particular type(S) of analysis) is necessary to support DQOs for a final nature and extent investigation, closure evaluation, or stand-alone assessment of the vapor intrusion pathway. Other investigations can support DQOs using the elements indicated in the minimum data documentation requirements (MDDR) column.
Documentation requirements as specifically outlined in Table 3-A of the RCG should be provided with any related correspondence which contains analytical results. Full QA/QC is requested for analytical data used for final nature and extent and closure.
Should I test for total or free cyanide?
The approved method for total cyanide is EPA 335.2. Approved methods for free or amenable cyanide are SW-846 9014 and SW-846 9213. Free cyanide is usually the form that is of interest since it's the most toxic form of cyanide. It can combine with hydrogen in water to form hydrogen cyanide.
Does Indiana have a lab certification program?
Indiana does not have an environmental lab certification program. For performance standards for the operation of environmental laboratories, information is available at the National Environmental Laboratory Accreditation Conference website. The Indiana State Department of Health (ISDH) Laboratories are responsible for certifying Indiana laboratories under the Safe Drinking Water Act.