What Are Your Data Telling You?

A Budget and Schedule Streamlining Review & Summary of Anaerobic Reductive Dechlorination of Chlorinated Hydrocarbons

Several previous articles discuss simplifying and streamlining environmental data acquisition and evaluation.

Mindful consideration of the information covered in the aforementioned articles can increase project margins and provide tools for avoiding some common pitfalls, such as:

  • Misinterpretation of nondetect data as an indication that a site is not contaminated when samples have been diluted such that quantitation limits (QLs) are too high to support the conclusion. This can occur because
    • Matrices are not amenable to the analyses.
    • Contamination concentrations require large dilutions.
    • Analysts are reluctant to analyze samples at lesser dilutions due to not understanding project purposes, inexperience, to avoid instrument maintenance, or to protect expensive and delicate instrumentation.
  • Failure to plan for an approach to achieve site closure when it is not possible to achieve detection limits (DLs) less than regulatory levels
    • Because regulatory levels are usually established using toxicological studies, not instrumental analyses, current methodologies may not be able to achieve these values.
    • Identifying the approach for addressing this issue during the project planning phase, and securing client and regulatory approval of the approach when the plan is finalized, is more efficient than securing approval after samples have been analyzed.
    • Additionally, planning for this issue allows for identification of more sensitive methodologies if they exist and performance of a cost/benefit analysis for the use of such methods with cooperation of clients and regulators.
    • Equally as important, it provides a tool to avoid misinterpretation of such data as an indication that the site is contaminated.
  • Attempting to remediate to levels less than native background.
    • Sometimes Federal regulatory levels are less than native levels (ex: arsenic in the West) and it is crucial to perform site assessments against background data (or perform background studies) in such cases.
  • Long-term monitoring of common contaminants that have been misidentified as contaminants of concern (COC). In such cases, assessment of historical data is necessary and several sampling rounds may be required to identify and gain approval for eliminating these parameters.

These pitfalls are easily avoided with proper assessment of site data and data requirements. However, site data can provide far more information. This may require analysis of parameters that are not COCs so careful planning is important, because analysis for parameters that do not provide relevant information wastes time and money and does not support the protection of human health and the environment.

Natural attenuation is one example of a remediation process where analysis for non-COCs can provide valuable information. Natural attenuation occurs when naturally occurring processes reduce contamination in soil and groundwater. These processes occur in situ and include dilution, dispersion, volatilization and other natural processes. Monitored natural attenuation (MNA) is an approved remedy at some sites and involves collection of data to assess and document the efficacy of the attenuation process.

When MNA is in place, non-COC data can be used to confirm that conditions are amenable to attenuation and the presence of breakdown products. Aerobic or anaerobic conditions (or one and then the other), specific pH values, and the presence of specific metals and/or microbes may be needed. Natural attenuation may be enhanced through forcing a site to anaerobic conditions, introducing bacteria and/or feeding native bacteria, and/or temporarily altering the pH. In each case, data must be collected to determine if the desired conditions have been achieved, and subsequent data must be collected to determine if attenuation was enhanced.

Contaminants that may undergo natural attenuation include chlorinated solvents, certain metals, radionuclides, and oil & gas-related aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). For this article, the MNA process to be further considered is anaerobic reductive dechlorination (ARD) of chlorinated hydrocarbons, specifically ARD of the volatile organic compounds (VOCs) tetrachloroethene (PERC or PCE) and trichloroethene (TCE).

The primary or initial contaminant for this process may be either PCE or TCE. These contaminants are present in the environment due to past use as degreasers, dry-cleaning agents, and through use in manufacturing processes. The ARD process breaks down PCE to TCE, and TCE subsequently breaks down to cis-1,2,-dichloroethene (DCE) and trans-1,2-DCE. 1,1-DCE may also be produced. The DCE isomers break down to vinyl chloride, and vinyl chloride breaks down to ethene. If all PCE and/or TCE breaks down to ethene, remediation is complete, because ethene is not an environmental risk.

To assess if ARD is occurring, break down products are included in the analytical data set. If TCE (and/or PCE) concentrations are decreasing and vinyl chloride concentrations are increasing, the process is successfully progressing. Regulatory criteria for vinyl chloride are stringent and the concentrations and may exceed the action limit; however, additional actions are not needed to address the exceedances unless the process stalls at this stage or  if vinyl chloride is also present because manufacturing at the site included polyvinyl chloride (PVC) production. .

Because MNA can be unacceptably time-consuming, often taking many decades to progress, various enhancement processes, as previously noted, have been implemented. The ARD process may be bio-attenuated with the microorganisms Dehalococcoides (abbreviated as DHC or DHE), which can be naturally occurring or inoculated into a site. Even when naturally occurring, the native population may not be great enough to speed ARD to the desired extent. In such cases, the microorganisms may be fed with vegetable oil or molasses. The table below shows some of the analyses that may be used at an ARD site.

ARD Table

Additional information about ARD and various analytical parameters can be found at the EPA Clu-In website, here. The information at the link provides more detailed and extensive information as well as links to additional resources. However, in the experience of the authors, if results show that ARD is occurring, assessing other parameters at the frequency indicated at the Clu-In link is not necessary. Some of the tabulated analyses listed are high-cost specialty analyses that may not add value for your specific project. If you are unsure of the frequency and type of analyses needed at your site, we invite you to contact Oak Services, LLC for a consultation.

 References & Resources

2007, Agency for Toxic Substances & Disease Registry (ATSDR), https://www.atsdr.cdc.gov/csem/csem.asp?csem=15&po=5, November.

2014, ATSD, https://www.atsdr.cdc.gov/phs/phs.asp?id=263&tid=48, October.

1999, United States Environmental Protection Agency (USEPA) https://www.epa.gov/sites/production/files/2014-02/documents/d9200.4-17.pdf, April.

2012, USEPA, https://clu-in.org/techfocus/default.focus/sec/bioremediation/cat/Anaerobic_Bioremediation_(Direct), -.

2001, Unites States Geological Survey (USGS), Natural Attenuation Strategy for Groundwater Cleanup Focuses on Demonstrating Cause and Effect, January.

Laboratory Procurement, Data Quality, & Budget Management

Communication during the bidding stage and planning stage of your project is the first step in ensuring your data are of the appropriate type and quality. Clear communication at these stages provides your laboratory with information necessary for quoting accurate costs, enabling you to estimate your budget more accurately. Moreover, communication of project requirements at these stages allows your selected laboratory to become your partner in meeting your project Data Quality Objectives (DQOs). This entry discusses the type of information that must be communicated to achieve these goals.

What laboratory certifications are needed for your project? Do you need State certifications? How about Department of Defense (DoD) Environmental Laboratory Accreditation Program (ELAP) certification (not to be confused with State of California ELAP)? Perhaps you only need (or also need) a lab with National Environmental Laboratory Accreditation Program (NELAP) certification? This information may be provided in your Statement of Work (SOW), Performance Work Statement (PWS) or Request for Proposal (RFP). However, if not provided, your client will expect you to determine what certifications are needed and ensure they are in place.

Once you have determined what certifications are needed, it’s important to ask your prospective laboratory to provide copies of the certifications with their quotation. If the certifications are due to expire soon, confirm the laboratory is taking the necessary steps for renewal.

It is wise to write the requirement into both your request for quotation (RFQ) and your contract that the necessary certifications be maintained and/or renewed and copies provided to you for the life of your project. Putting a contract in place with your laboratory helps ensure that the laboratory will prioritize your work and codifies both party’s expectations and requirements. It allows you to establish and enforce penalties and fee reductions for failure to perform or late delivery of data. Should such issues arise, a purchase order (PO) will not serve you well.

What else do you need to determine? What else does the laboratory need to know?

Methods and Parameters, as well as Compound Lists

Compound lists for methods are not the same for laboratories across the industry. For example, a laboratory will provide you with a lengthy compound list for SW-846 Method 8270D for Semivolatile Organic Compounds (SVOCs), but the list will not be the same for all laboratories. The laboratory target compound list (TCL) may not match the list for your project (which may also be called the “TCL”). The lab’s TCL may not match the United States Environmental Protection Agency (EPA) TCL. Therefore, if you have specific target analytes to be addressed by your project, it is imperative to identify these for the laboratory.

Turn Around Times (TATs)

Are you performing remediation? Do you need expedited TATs for another reason? The quickest results will be available as preliminary data only; however, if you have taken care in selecting your laboratory, this shouldn’t be too scary.

You will need to budget for the laboratory’s mark-up for providing results to you at an expedited pace. Usually, the laboratory mark-ups, even at 100% or more, are considerably less than project $ spent on extended stand-by time.

The laboratory must agree to the expedited TATs up-front (during the bidding stage) and in advance of receiving the samples. Once your project is in full swing, you’ll be placing your bottle order (request for coolers and containers) at least a week in advance. The laboratory may be operating at close to capacity, so this is a good time to remind them of the expedited TATs required on the samples they’ll be receiving. If your project schedule has shifted, you will need to re-confirm that they can meet your TAT expectations.

Data Deliverable Expectations

You can usually save money by not using hard copy data packages. Many laboratories have portals you can use to download your data. If not, the data packages can be burned to CDs and shipped to you.

If your project requires data validation, it may be wise to request full Level IV packages (data summaries and raw data), so that any data quality concerns can be investigated immediately by your validators, without incurring a schedule delay waiting for the laboratory to deliver the additional data.

Additionally, your chemists and database managers may need to weigh in on the electronic data deliverable (EDD) requirements. What is needed for your validators and systems may not be the same format required by your client (be sure you have your location data and field data available too!)

Most labs include at least one EDD format in their costs; however, you may need to make budgetary adjustments if the laboratory will be required to produce two or more EDDs. It’s therefore wise for you and the laboratory to be aware of such needs during the bidding and planning stage.

Project Action Limits/Criteria

Whether your project action limits (PALs) are identified by your client or your team identifies the regulatory criteria for your PALs during project planning, there is a possibility that some values will be lower than your laboratory can achieve. You will need to know if there are alternate methods that can achieve quantitation limits (QLs) below these PALs and if your laboratory can perform them.

If your client has not identified methods for you and modifications to standard methodologies are commonly available that can achieve QLs less than your PALs, your client may expect you to identify and budget for the modified methods. This can easily be addressed during the laboratory bidding stage through direct communication with your prospective laboratories.

Alternately, some of your target compounds may have PALs too low for current methodology to achieve. This is because regulatory criteria are often based on toxicological studies run on biota, not on what current methodologies and instruments can “see”.

If your PALs are too low for current methodologies to achieve, you will need a plan to address this. You will not want to destroy a solid working relationship with your highly qualified laboratory by demanding they do the impossible, and you will not want to spend your schedule and budget chasing the wind. Communication of the proper requirements and the right time is the key to your success.


Although this article is written with environmental projects and analyses in mind, with appropriate adjustments, this approach can apply to various industries. If you have questions or comments, leave them in the comments section below. If you’d like to talk to Oak Services about writing your laboratory RFQ, procuring qualified laboratories, managing laboratories, and/or writing or reviewing your project plans, please, contact us and let us know what you’re looking for.

About the author: Dianne McNeill is a Proposal Manager and Senior Scientist with Oak Services. She presented the paper “Laboratory Data Quality and the Bottom Line” (McNeill & Thielke) at the 2007 EPA Annual Conference on Managing Environmental Quality Systems. Abstracts are available for free download here.



Environmental Data Validation – What It Is and Why We Do It

Costs of inaccurate or inadequate data can be steep. Problems with data quality can result in tangible and intangible damage ranging from loss of customer/user confidence to loss of life and mission. – Department of Defense (DoD) Guidelines on Data Quality Management

…..more than a decade’s experience has demonstrated that integrity is not a safe assumption. United States Environmental Protection Agency (EPA), 2002 Guidance on Environmental Data Verification and Data Validation

Data validation is absolutely essential at key decision points, such as determining the boundaries of groundwater contamination. – EPA, Region 9

We must ensure project objectives are met through adequate, accurate data. We must also take steps to ensure project decisions are based upon legally defensible data.

In the terminology of the United States Environmental Protection Agency (EPA) and the Department of Defense (DoD), measurement performance criteria (MPC*) or data quality indicators (DQIs) are the criteria for evaluation of project data. Your MPC support your data quality objectives (DQOs), which are objectives your data must satisfy to be “good enough” to support your project decisions. This means MPC support your DQOs, which in turn support the project objectives. However, your MPC do not have to be perfectly met for your DQOs to be achieved.

How do you determine your MPC and DQOs? Your MPC and DQOs are set during project planning. The optimized Uniform Federal Policy – Quality Assurance Project Plan (UFP-QAPP) lays out steps and some guidelines to assist you in determining what they should be. The prompts in the optimized UFP-QAPP format can be useful for project planning, even if this challenging document is not required for your project, and you don’t go on to use the template. Referencing the prompts can help you meet EPA criteria for project plans and determine when to engage your engineers, geologists, and chemists during planning. Though this may seem time-consuming, this approach to planning will save you valuable project execution time once your project is in progress.

Your chemists can help develop and/or identify your MPC. It may be appropriate to default to the current DoD Quality Systems Manual (QSM) criteria, method criteria, or historical laboratory criteria. Because your planning time is not unlimited and because you cannot predict every field and laboratory condition that may affect your data, using established criteria as your MPC is usually a good approach. Your MPC are intended to be a guide for evaluating how well you met your DQOs and not meeting MPC is an indication that a closer review of the data may be needed, but MPC are not a prescriptive measure of your DQOs.**

So, how do you know if your MPC have been met well enough for you to make sound project decisions? How do you know your project decisions are based upon legally defensible data? Data validation is how you do that.

During project execution, your validators evaluate your data to determine if any of your data are not usable for project purposes. Ideally, this evaluation is not simply an “in is in, out is out” approach to evaluating quality control (QC) outliers, but rather takes your overall project goal into account. With use of Automated Data Review (ADR) and similar tools, 60-80% of what a validator does can be automated. However, not all of the required assessments can be automated, and experience and the ability to look at the big picture have value in minimizing risks.

Although laboratories perform several levels of data review, it is illegal for them to “validate” their own data in most cases; this is considered a conflict of interest. Under deadline and holding-time pressure, mistakes can occur.

Scenario 1:

Validation is required by your client for your project which involves a simple dig and haul remediation of lead in soil with no migration to groundwater. Easy, right? You get your preliminary results which are all nondetects, place your clean fill, and move on. Your final data arrives a few weeks later and your validators determine the calibration for lead was improperly performed or calculated by the laboratory and your nondetect values for lead reported at a 2 milligram per kilogram (mg/kg) quantitation limit (QL) should have been reported at 20 mg/kg.

If an “in is in, out is out, get it done as quickly as possible” approach is used, this could lead the validators to reject these nondetect values, and you may have to remobilize, re-excavate, and collect and analyze additional samples from your site. Your project has just cost twice as much as anticipated.

However, if your validators have access to your project goals and are taking a “whole project” approach, they will have access to your project action limits (PALs) or decision criteria, which is likely to be between 100 mg/kg and 400 mg/kg for lead, in which case, nondetect values with QLs raised to 20 mg/kg are clearly usable to determining you have met your criteria.

If any of your project documents, inclusive of your Request for Proposal (RFP), Statement of Objectives (SOO), Statement of Work (SOW), or Performance Work Statement (PWS) require data review per the DoD QSM, the UFP-QAPP, or reference ADR, your client is requiring data validation. Clients expect you to understand their requirements and to know the content of their guidance documents.

Data validation is ideally performed and often required for confirming remedial action is complete, for monitoring and operations assessments, and for determining that materials are suitable to be put into or back into the ground (ex: using clean site soils as backfill). Data validation may also be needed for site characterization, depending upon purpose of characterization. Data validation provides assurance that data are adequate for the intended use. Data that are adequate for the intended use lead to sound project decisions. Data validation may also save you a day in court.

Scenario 2:

The new owner of the property in Scenario 1 plans to sue the previous owner, your client. You are called upon to defend your assertion that you completed remediation to the satisfaction of the regulatory requirements of the time; however, ten years have passed since you completed this project and you don’t recall the details of this small project all that well. You are concerned when your data are called into question. However, because your validators clearly and thoroughly documented the calibration issue, raised the reporting limits, and showed your soil samples were clean to 20 mg/kg, the case is dismissed.

Data validation is, however, not always needed. It is rarely needed for waste characterization, and data indicating additional actions are needed (such as excavating wider or deeper) do not require validation. In these cases, responsibility is being assumed by another party (i.e. the waste acceptance facility or landfill) or your team will be taking additional actions before you make the final project decisions. In some cases, the level of validation (such as those commonly referred to as Levels 2, 3, and 4) may be minimized unless issues arise, depending on project objectives. Data validation performed in a manner that is tailored to your project helps ensure project objectives are met and risk is minimized.

If you have questions or comments, please leave them in the comments section below. If you’d like to find out if Oak Services is the right company to write or review your project plan, perform your environmental data validation or assess your validation needs, please contact us and let us know what you’re looking for.



*The parameters evaluated with MPC were historically referred to as “PARCC”, which is an acronym for precision, accuracy, representativeness, comparability, and completeness. PARCC is generally considered to be an obsolete term now, and MPC includes an evaluation of data precision, accuracy, bias, sensitivity, and completeness.

** Although it is possible to tailor your MPC very specifically to your project, it is not possible to anticipate every possible field and laboratory condition that may be encountered during project execution. It is reasonable to use default MPC with room for professional judgement. This approach can be formalized in your QAPP, along with a requirement that professional judgment calls will be briefly explained in your data validation summaries or reports.

About the author: Dianne McNeill is a Proposal Manager and Senior Scientist with Oak Services. She has 23 years of experience in the environmental sciences, with 15 years environmental data validation experience inclusive of 10 years experience training new validators. She also has 7 years of environmental laboratory experience, with a focus on GC/MS analysis of VOCs and SVOCs and LC/MS and LC/MS/MS analysis of explosives, dyes, and specialty parameters.