John Fitzgerald, Massachusetts Department of Environmental Protection, Wilmington, MA
Elizabeth Callahan, Massachusetts Department of Environmental Protection, Boston, MA

In Massachusetts, the assessment and cleanup of contaminated sites is governed by the Massachusetts Contingency Plan (MCP).  The MCP, like other similar programs and regulations, is “risk based”, with quantitative risk management standards for Threshold and Non-Threshold Health Effects.  Unlike other programs, the MCP also specifies remedial requirements for certain contaminant transport conditions – termed Critical Exposure Pathways or CEPs – regardless of quantitative risk estimates or projections.  CEPs are limited to (a) vapor-intrusion pathways at homes and schools, and (b) impacts to on-site drinking water wells at homes and schools.  These pathways/exposures must be eliminated or mitigated, to the extent feasible, with feasibility defined as remedial cost vs. benefit.  The CEP requirement seeks to recognize and address the uncertainties that exist in our understanding of long-term low-level chemical exposures to the most sensitive receptors (children and pregnant women), while at the same time, allow for consideration of practical and economic constraints on addressing such exposures.

The purpose of this workshop is to articulate regulatory requirements and expectations, and provide specific, “real world” guidelines and rules of thumbs on investigating, recognizing, evaluating, and addressing CEPs, with particular emphasis on vapor intrusion pathways.  

14) Characterizing PAH Bioavailability in Sediments for Remedial Decision-Making  

David V. Nakles, PhD, ENSR Corporation (dba The RETEC Group, Inc.), Monroeville, PA
Joseph P. Kreitinger, PhD, ENSR Corporation (dba The RETEC Group, Inc.), Ithaca, NY
Stephen C. Geiger, PhD, CPSS, ENSR Corporation (dba The RETEC Group, Inc.), Springfield, VA  
Nick Azzolina, ENSR Corporation (dba The RETEC Group, Inc.), Ithaca, NY 
Edward F. Neuhauser, National Grid, Syracuse, NY

This workshop will cover the integration of contaminant bioavailability in regulatory sediment guidance and the results of the Sediment Contaminant Bioavailability Alliance (SCBA) evaluations of PAH bioavailability at more than 12 industrial sites throughout North America . Case studies will be presented that highlight the importance of contaminant bioavailability for efficient and cost-effective sediment management. These studies will also emphasize the incorporation of contaminant bioavailability data into better remedial designs.  

15) Theory and Application of Molecular Biological Tools (“MBTs”) and Biogeochemistry to Bioremediation Process Monitoring and Monitored Natural Attenuation Programs 

Eric C. Hince, P.G., Geovation Engineering, P.C., Florida, NY
Aaron Peacock, Ph.D., Haley & Aldrich, Oak Ridge, TN

Molecular biological tools (“MBTs”) are revolutionizing the way site bioremediation and MNA programs are justified, planned, monitored and proven in the field.  MBTs are now readily available to environmental professionals, and when combined with the monitoring of key biogeochemical parameters, they offer the capability of proving biodegradation and/or determining biodegradation potential and rates.  This is accomplished by identifying key microbes and biodegradation processes by making connections between the putative biodegradation processes and the microbes and biogeochemical conditions observed in the field.  The intent of the proposed workshop, as a successor to our previous “anaerobic processes” workshop, is to provide participants with a working knowledge of MBTs and their application to site-remediation and MNA projects.  Particular emphasis will be placed on case studies concerning the application of MBTs to biodegradation processes.  The workshop will cover:

Theory and application of commercially available MBTs including:

Phospholipid / Fatty Acid (PLFA) biomarkers

Quantitative / real-time PCR targeted to nucleic acid biomarkers for both key taxonomic groups and functional genes

Denaturing gradient gel electrophoresis (DGGE) profiling of microbial communities

Fluorescence in-situ hybridization (FISH)

Quantitative and qualitative microscopy

Overview of Bio-Trap samplers and their applications:

In-situ collection of biomass for subsequent molecular analyses

Stable isotope probing (“SIP”) of in-situ biodegradation processes using Bio-Traps loaded with 13C-labeled compounds or surrogates of interest (e.g., benzene, MTBE, cDCE)

Fluorinated analog probing (“FAP”) of reductive dechlorination processes using Bio-Traps loaded with fluorinated surrogates of compounds of interest (e.g., TCFE for TCE; DCFE for cDCE)

Overview of compound-specific stable isotope analysis (“CSIA”)

Handout materials on groundwater biogeochemistry will be provided (from the predecessor workshop) but this topic will mostly be addressed in the case studies in conjunction with data from MBTs

Participants will be encouraged to bring site characterization and ground-water sampling data from their own projects/sites into the workshop to facilitate an interactive case study / data-review session with the presenters and other participants.

16) Geochemical Evaluations of Metals in Environmental Media:  How to Distinguish Naturally Elevated Metals Concentrations from Site-Related Contamination

Karen Thorbjornsen and Jonathan Myers, Shaw Environmental, Inc.

Metals concentrations in soil, sediment, groundwater, and surface water are problematic in site investigations because they often exceed screening criteria.  However, it is not always clear whether these concentrations represent site-related contamination or simply naturally high concentrations.  It is well known that trace elements are naturally associated with a limited number of minerals in the soil and sediment matrix (or with specific suspended particulates in groundwater and surface water) under a given set of environmental conditions.  These processes result in correlations between trace elements and the major elements present in the host minerals, as long as no contamination is present.  For uncontaminated samples, positive correlations and consistent elemental ratios are observed in scatter plots of specific trace versus major element concentrations.  Contaminated samples are identified by their anomalously high elemental ratios.  Additional factors are considered during evaluations of metals in groundwater and surface water, such as pH effects, redox effects, aqueous complexation, and salinity gradients.

When properly performed, geochemical evaluations greatly reduce the probability of falsely identifying contamination; can be performed without a large, statistically valid set of background samples; precisely identify contaminated locations, thereby focusing remediation efforts; and provide mechanistic explanations for naturally elevated trace element concentrations, which a purely statistical approach cannot provide.  In addition, the evaluations are performed using data obtained from standard analytical methods that are normally employed at site investigations.  The instructors have successfully applied geochemical evaluations at over 36 commercial and military facilities (incorporating hundreds of discrete investigation sites) across the U.S. , its territories, and Mexico for the past 9 years.  These evaluations provide insightful case studies for the short course.

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