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Vol. 5 Issue 3


Summer 2009

Understanding your lab report Method Detection Levels, Method Reporting Levels and “J-flagged” data

By Steve Albrecht, Project Manager

Reporting Terms to Know

When you receive a report from your analytical laboratory, it may include some unfamiliar terms such as “MDL,” “MRL” and “Jflags.” While these terms can be confusing, their meanings are an important part of understanding the data that is being reported. The Method Detection Limit (MDL) is the lowest level of a substance that can be distinguished in a sample, whereas the Method Reporting Limit (MRL) is the smallest amount of a substance that can be reliably quantitated in a sample. The information that lies between the MDL and MRL is sometimes expressed as J-flagged data. J-flagged data is a standard qualifier used by the Environmental Protection Agency (EPA) and is used to indicate that a certain substance is present in a sample, but the actual amount is an estimated value. To better understand this and how it relates to MDL and MRL, consider the analogy of needles in a haystack. The first question to ask when searching for needles in a haystack is “At what level can we detect any needles at all?” This relates to the MDL. The EPA defines the MDL to be “the minimum concentration of a substance that can be measured and reported with 99 percent confidence that the analyte concentration is greater than zero.” Likewise, the MRL is defined by the EPA as “the minimum concentration of an analyte… that can be identified and quantified above the MDL and within specified limits of precision and bias during routine analytical operating conditions.” In our example this is the level at which the laboratory can provide a high degree of confidence as to the number of needles in a haystack. Because needles first need to be detected in order to count them, the MDL is lower than the MRL. In many cases, clients are only concerned about data that is quantifiable. In our example suppose we determine an MRL of 150 needles per haystack. Therefore if 150 or more needles are present

MDL: Stands for Method Detection Limit, which is the lowest level of a substance that can be distinguished in a sample. MRL: Stands for Method Reporting Limit, which is the smallest amount of a substance that can be quantitated in a sample. J-flagged data: The information that lies between the MDL and the MRL is sometimes expressed as J-flagged data, which is used to indicate that a certain substance is present in a sample, and is an estimated value. in a haystack, we can confidently count them. The resulting value can be compared to EPA standards based on their concentration. If the client was also interested in knowing if needles were detected below the quantitation limit, the report would list both the MDL and MRL. A result below the MDL is reported as “ND” or “nondetectable.” For results that are between the MDL and MRL, a numerical result is provided with a J-flag or footnote. For example, if we found 100 needles, the result would be expressed as “100 J needles/haystack.” The J simply indicates that the results are an estimate and that the parameter is detectable. Occasionally, we are asked why the MRL and/or MDL are elevated above the normal limits. This can occur when a dilution might have taken place during the testing. Samples may be diluted for two reasons. First, the concentration of the analyte of interest exceeds the linear range of the technique. Second, the sample matrix may be interfering with the analysis by the existing protocol. In some situations, J-flag data may be valuable. Be sure to contact your project manager if you have any questions about reporting options.

Lab Manager’s Corner: Laboratory Reports Hopefully you have been having a nice summer and your business has been doing well considering the economic downturn. In this issue, we discuss the definitions of various reporting terms, including Method Detection Limits, Method Reporting Limits, and J-flagged data. If you have any questions about your specific reporting needs, our project managers are happy to provide insight and assistance.

Additionally, we are in the process of attaining a State of Iowa laboratory certification for environmental analysis. Once finalized, we will provide you with information regarding the services that we offer in Iowa. We are also pleased to announce that our laboratory was recently approved by the Minnesota Department of Health to analyze cyanide in wastewater. Cyanide can generally be found in industrial waste streams and the majority of samples we analyze are the result of the permit regulations of the National Pollution Discharge Elimination System (NPDES). If you have any questions, or comments please contact me at 952.995.2650. - Tom Wagner

Is your construction site in compliance with state storm water requirements? By M. Rebecca Forman, Ph.D., C.E. An evening rain shower might seem nice at the end of a hot day, but rain can present challenges to construction sites. It is critical that construction site managers have a plan in place to deal with storm water, as runoff from construction activities has the potential to deposit large quantities of sediment and other pollutants into lakes, streams, and other water bodies. This deposition can harm aquatic ecosystems and create other problems, including cloudy water, which blocks light for rooted plants and decreases visibility for animals. Additionally, it can contribute to algal blooms, which are formed due to increased phosphorus input. Other side effects may include decreased oxygen content, which can kill fish, and an overall decline in the aesthetics of the water body. Storm water is defined under Minnesota Rules 7077.0105, subp. 41(b) as “precipitation runoff, storm water runoff, snow meltoff, and any other surface runoff and drainage.� In simple terms, it is water flow that results from precipitation and that occurs immediately following a rainfall or snowmelt. With tougher permitting and enforcement at the federal, state, and local levels, land developers should consider taking a proactive approach to storm water planning and permitting to avoid costly delays and penalties. History of Storm Water Regulation The Clean Water Act and its amendments prohibit the discharge of any pollutant (including sediment from a


Silt fences and other parameter protection can often be seen at construction sites. construction site) to a water body in the United States unless it has been authorized by a National Pollutant Discharge Elimination System (NPDES) permit. In Minnesota, the Pollution Control Agency (MPCA) is the storm water permitting authority and administers the federal NPDES program. Phase I regulations began in 1987 and required any site with soil-disturbing activities greater than five acres to obtain a NPDES permit. Phase II regulations began in 2003. Among the changes between the Phase I and Phase II regulations are the size of the site requiring permitting; Phase II regulations require sites disturbing one acre or greater of soil to obtain a NPDES permit. In addition, Phase II requires parcels smaller than one acre, but part of a larger common development, to obtain permit coverage. For information about how to obtain a storm water permit in Minnesota see July2008PCVol11_Issue3.pdf or call M. Rebecca Forman at 651.487.7013. Continued on page 3 - see STORM WATER

Meet Katie Rinker ‡/DE$QDO\VW,‡ Katie Rinker enjoys the day-to-day aspects of working in the prep lab at the Braun Intertec Analytical Laboratory. Each day she prepares samples for the analysis of semi-volatiles, Polycyclic Aromatic Hydrocarbons (PAHs), pesticides and a variety of other chemicals, all the while helping to organize workload in the lab. “I love being in the lab,” she said. “I really like the variety of projects that I get to work on, and it’s great to interact and collaborate with my colleagues.” Although Katie has only been with Braun Intertec since last spring, she brings an enormous amount of experience to her job as a Lab Analyst I, helping to coordinate projects in the Prep Lab. During the past 10 years Katie has served as a marine scientist and a research assistant analyzing water samples. Most recently she served as a project manager in the regulatory group at a large lab working with complex adhesives. Katie earned her bachelor’s degree in marine science from Texas A&M University, and has a master’s degree in earth and environmental science from Tulane University in New Orleans.

“Katie has worked on very difficult projects in the past. Her experience with environmental testing, as well as leading projects, make her a tremendous asset to our lab,” said Steve Albrecht, project manager at Braun Intertec. In her free time, Katie enjoys gardening and loves to travel. She is especially proud of having traveled to all 50 states, and really enjoyed spending time in the Rocky Mountain region of Colorado and on the East Coast. One of the things that helped lead her to a career in science was seeing beluga whales at the Minnesota Zoo when she was a child. As she progressed in her schoolwork, Katie’s passion evolved into lab work.

STORM WATER - Continued from Page 2 Construction site inspections help verify the efficacy of the erosion prevention and sediment control measures. Site inspections are performed by qualified personnel every seven days and within 24 hours of one-half inch of precipitation, and must occur throughout the entire year. Inspections must be documented, and inspection reports must be kept on the construction site. Non-compliant issues must be rectified within set periods of time (outlined in the permit) and may include off-site sediment tracking onto paved surfaces, sediment in the curb line, silt fence more than one-third full of sediment, and runoff from stockpiles. Upon completion of the construction project, “final stabilization” must be achieved on the site before termination of permit coverage. Final stabilization requires that any soil-disturbing activities at the site have been completed; that any soils must be stabilized by a uniform perennial vegetative cover with a density of 70 percent over the entire pervious surface area; that temporary synthetic and structural erosion prevention and sediment control best management practices be removed throughout the site; and that permanent storm water treatment systems meet permit requirements.

Our laboratory performs a number of liquid and soil analyses that can assist you with storm water site projects. Permit coverage is terminated through submittal of a Notice of Termination (NOT). The NOT must be submitted within 30 days of final stabilization or when another owner or operator assumes control of the site. For more information about how our lab can assist you with water and soil testing, please contact Steve Albrecht at 952.995.2622.


Questions, Requests and Comments Thomas Wagner, 952.995.2650 Steven Albrecht, 952.995.2622 Braun Intertec Corporation 11001 Hampshire Avenue S Minneapolis, MN 55438 This newsletter contains only general information. For specific applications, please consult your engineering or environmental consultants and legal counsel.

Analytical Laboratory Summer Hours The Braun Intertec Analytical Laboratory is open to receive samples on Saturdays from 8 a.m. until noon extending through Oct. 31, with the exception of Labor Day weekend. Monday through Friday our normal receiving hours are from 8 a.m. to 5 p.m. If you have any questions, you can contact our lab at 952.995.2600. As always, if you have a special project requiring sample receipt during off hours, please contact your project manager and we’ll accommodate your needs.

Braun Intertec Analytical Laboratory 11001 Hampshire Avenue S Minneapolis, MN 55438 Š2009 Braun Intertec Corporation

Providing engineering and environmental solutions since 1957