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Rain gardens are becoming a popular way to improve water quality by absorbing stormwater

and preventing the pollutants it contains from entering stormwater drains. As rain runs off rooftops and driveways, it collects in the depression of a garden planted with species that can tolerate moist conditions. As the water soaks into the ground, a natural filtering occurs.

Stormwater ponds function in a very similar way. As runoff from freeways collects in a basin, some pollutants settle to the bottom while others are degraded by biological processes. Despite how this sounds, these holding ponds are not an infinite sink for pollution and require regular maintenance as contaminated sediments accumulate.

In June 2012, the Minnesota Pollution Control Agency (MPCA) released a document designed to help municipalities deal with the issues of maintaining stormwater ponds. The document, “Managing Stormwater Sediment Best Management Practice Guidance for Municipalities,” can be found on the MPCA website: http://www.pca.state.mn.us/.

When determining an action plan for maintenance of stormwater ponds, assessing the type and amount of pollution present is an important step that requires laboratory analytical testing. The contaminants of concern are primarily Polycyclic Aromatic Hydrocarbons (PAHs), arsenic and copper. PAHs are a group of chemical compounds with specific characteristics that are found naturally in fossil fuels and are a byproduct of fuel combustion. Some PAHs have been determined to be carcinogens, and the compounds included are identified as cPAHs.

Studies conducted by the MPCA and others have found that with respect to sediments in stormwater ponds, the most significant source of PAHs is coal-tar-based sealants. Sealants used on off-street pavements, including parking lots and driveways, are typically applied to the surface so the underlying asphalt lasts longer and appears more attractive. Asphalt-based sealants contain about 1000 times less PAHs and are quickly replacing the coal-tar-based sealants. In fact, several municipalities in Minnesota, including the City of Minneapolis, have banned the use of coal-tar-based sealants, and many home improvement stores have stopped carrying them in favor of the more environmentally friendly asphalt-based sealants.

As this is a developing area of concern, the current MPCA guidance document describes several changes in sampling and analytical testing for PAH/cPAH compounds relative to previous requirements.

New Regulatory Guidance for Managing Stormwater SedimentsBy Rebecca Hofstad, Ph.D.,Analytical Laboratory Technical Director rhofstad@braunintertec.com

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Rebecca Hofstad’s home rain garden is a beautiful way to naturally filter stormwater and keep pollutants from entering stormwater drains. See NEW REGULATORY GUIDANCE - Continued on page 3

A B R A U N I N T E R T E C P U B L I C A T I O N

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Braun Intertec Analyst Profile: Meet Michael Whebbe, Lab Analyst IAfter spending a couple months learning the lay of the lab in sample receiving, Michael Whebbe jumped into his new role performing oil and grease analysis on water samples. He’s working toward becoming the lab expert on oil and grease, as well as providing support on other metals and inorganic analyses, including Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Chemical Oxygen Demand (COD), and Toxicity Characteristic Leaching Procedure (TCLP).

“I enjoy learning about the various testing procedures and not just focusing on one thing,” Michael says. Working in the analytical laboratory has provided him the opportunity to become a well-rounded analyst. From learning to measure total solids to playing with gravimetrics, Michael has enjoyed the variety. “I just keep picturing some of the greasiest, nastiest samples that I’ve filtered recently and thought that it’s always interesting to see how high of a result we’ll get,” Michael says. In the lab, the discovery process is endless and curiosity is a valued attribute.

Michael graduated from the University of Minnesota with a biology degree, which the other lab analysts (mostly chemists) don’t let him forget. But, Michael’s passion for biology is deeply rooted thanks to his high school biology teacher. “My teacher’s passion for biology was infectious,” Michael says. Having a different background in the lab contributes to the collaborative and diverse culture, and in all fairness, Michael also had a good helping of chemistry in college.

When Michael isn’t in a lab coat indoors, he’s outside fishing or hunting. I just love being outdoors, he says. Michael likes hunting duck, pheasant, and goose. But, he loves fishing on a lake. Currently, Michael is gearing up for ice fishing.

When the Braun Intertec Analytical Laboratory started in the early 1980s, our primary function was to support the geotechnical side of Braun Intertec. Generally, the requests were for basic chemistry testing related to soil analysis, such as pH and conductivity. During the mid-1980s as environmental awareness increased, our laboratory started conducting analyses that were directly related to the concern of protecting the environment. The samples and analytical requests were still primarily related to Braun Intertec geotechnical projects. As word spread that Braun Intertec operated a chemistry laboratory, the laboratory started receiving requests from clients “outside” of the company.

During the 1990s, the environmental regulatory directives from the Environmental Protection Agency (EPA) and the Minnesota Pollution Control Agency (MPCA) really began taking shape. The Minnesota Department of Health initiated a laboratory certification program, and we became a full-fledged environmental testing laboratory. Due to the growth of the environmental market, Braun Intertec created its own environmental consulting group. Subsequently, the majority of the laboratory testing conducted at that time was for that internal group. Simultaneously, the laboratory’s external client list and revenue was continuing to grow. With business booming, we were in need of more space.

In 2002, Braun Intertec moved from Eden Prairie to its current location in Bloomington. Due to our business growth at that time, we were able to design a laboratory in our new space with a more efficient floor plan for the various areas of analytical disciplines. With our laboratory expansion, we have been able to showcase our facilities to visiting clients and associates, and demonstrate our many capabilities.

In our next issue, we will take a look at how our client relationships have developed throughout the years, and the importance of all our clients to the laboratory’s success. Until then, our laboratory staff thanks you for your continued support and welcomes your feedback.

Lab Manager’s Corner: Formulating Change

Michael Whebbe’s catch of the day was a 3.5-pound bass from Woman Lake near Longville, Minn.

Tom Wagner, Analytical Laboratory Manager twagner@braunintertec.com

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For starters, the number of samples collected is dependent on the surface area of the pond. Before the samples are submitted to the laboratory, rocks, pebbles, trash, large invertebrates and large pieces of detritus must be removed in the field. Overlying water should also be carefully removed after sediment samples have settled. Finally, a recommendation by the sampler should be made to the laboratory regarding an appropriate sample to be used as the source for the Matrix Spike (MS)/Matrix Spike Duplicate (MSD). This recommendation helps increase the likelihood of obtaining usable quality control data. Any information about the site, previous analysis results, or location may help samplers identify the sample that is likely to be the least contaminated.

There are also changes in how the analysis of PAHs/cPAHs is conducted and how the data is reported. For instance, results that are between the Method Detection Limit (MDL) and Method Reporting Limit (MRL), known as j-flag data, should be reported. Also, interferences should be dealt with by passing extracts through clean-up columns instead of diluting extracts to reduce the level of interferences. Lastly, the number of cPAH compounds that must be included in the report has been reduced from 25 to 17, but there are several non-carcinogenic PAH compounds that are required as well. It’s important to carefully clarify with the MPCA the list of compounds needed for your specific project prior to submitting samples for analysis.

Moreover, the guidance includes a revised policy for the treatment of non-detect data when using the results to calculate a value equivalent to the PAH compound Benzo[a]pyrene, the B[a]P equivalent. An Excel worksheet is available on the MPCA website: http://www.pca.state.mn.us/index.php/view-document.html?gid=11853.

Decision makers in municipalities as well as environmental consultants should note that this article is a simple summary of the guidance document. For more details, please see the full document. It’s also very important to be aware that the guidance discussed in this article applies strictly to stormwater ponds. The analysis of sediment for other sampling situations may have different requirements. When making a request for analysis, it’s critical that the client asks for the correct test so that all of the necessary compounds are included.

For general information about coal-tar-based sealants, PAHs and the environment, see the following United State Geological Survey publication: http://pubs.usgs.gov/.

NEW REGULATORY GUIDANCE - Continued from page 1

Most communities have hundreds of stormwater ponds scattered throughout their municipalities. Accurately measuring the sediments running off into these ponds is crucial for predicting their lifespan. High sediment loadings can quickly fill up stormwater ponds, shortening their lifetime and resulting in significant expenses when dredging out the deposited material. Performing the appropriate laboratory tests can help predict sediment loading.

Total Suspended Solids (TSS) testing has been used for many years in analytical laboratories to predict sediment loading. This method was originally developed to analyze wastewater, but it has also been used in stormwater investigations. Unlike relatively uniform wastewater samples, stormwater samples are variable due to a wide range of particle sizes – from substances not seen by the naked eye to coarse sand or rocks. The variable particle sizes can create inaccuracy issues when subsampling for analysis, which occurs in the TSS analysis. Large particles, which are common in stormwater, settle rapidly after vigorous shaking, resulting in a subsample that is non-uniform. The Suspended Sediment Concentration (SSC) method, another sediment-load test, uses the entire sample collected to avoid this problem. When analyzing a heavy-sediment load sample that quickly settles, using the entire sample, as is done by SSC, helps minimize error and biased data.

Several studies of SSC and TSS data correlations have been done by the United States Geological Survey (USGS). They recommend that the SSC method be used to provide suspended sediment data instead of TSS, unless it can be demonstrated that these analyses produce similar results. Using biased TSS data can result in load calculation errors of several orders of magnitude, which becomes especially important in design and maintenance of stormwater runoff ponds. Using the SSC method provides the best data quality for making the most cost-effective decisions.

By Steve Albrecht, Project Manager, salbrecht@braunintertec.com

A Better Way to Measure Stormwater Sediment Loading Total Suspended Solids Testing versus Suspended Sediment Concentration Method

©2012 Braun Intertec Corporation

This newsletter contains only general information. For specific applications, please consult your engineering or environmental consultants and legal counsel.

Questions, Requests and Comments

Thomas Wagner 952.995.2650twagner@braunintertec.com

Steven Albrecht 952.995.2622salbrecht@braunintertec.com

Braun Intertec Corporation11001 Hampshire Avenue SMinneapolis, MN 55438

Recently, a few questions have come up regarding toxicity characteristic leaching procedure (TCLP) testing.What is the holding time for a TCLP sample? Once samples are collected, they have 14 days to be leached. After the leaching procedure has been completed, the normal holding times take effect.

How much sample is needed for TCLP? The leaching procedure takes a minimum sample size of 100 grams for metals and semi-volatile compounds. An additional 100-gram sample is needed for the volatile analysis. It is best to collect at least a 500-gram sample in a glass jar.

What is the fastest turnaround possible for a TCLP analysis? Turnaround depends upon the tests requested. The TCLP leaching requires a minimum of 18 hours to perform the leachate analysis. Additional time is needed for sample extraction after the leachate procedure. Thus, 48 hours is a minimum turnaround time for metals analysis, longer if volatiles or semi-volatiles are needed.

Additional information can be found on the Braun Intertec Analytical Laboratory FAQ webpage: http://www.braunintertec.com/SERVICES/AnalyticalLaboratory/FAQs.aspx.

Analytical Laboratory Holiday Hours

We are closed December 24th, 25th and January 1st. We will be openNew Year’s Eve day.

No Saturday deliveries until April 2013.