1. Bureau of Materials and Research
2018 AASHTO RAC/TRB Annual Meeting
High Value Research Sweet 16
Ann Scholz, P.E., Research Engineer

2. Dirt isn’t just under your Fingernails
It doesn’t make for a pretty picture, There are many aspects to Limited Reuse Soils that impacted various divisions and bureaus at NHDOT. They are currently managed through various ways and continue to evolve.
Limiting the Impact of Lightly Contaminated Soils

3. NHDES Definition of “Contamination”
“The presence of any regulated contaminant…
other than naturally occurring substances at naturally occurring or background levels…
in soil…sediment…construction/ excavation debris or any other material…
At a concentration that has the potential to adversely affect human health or the environment.”
NHDES Env-Or – Definition of Contamination, as referenced from
Env-Sw 903 Contaminated Soils
what and where it is; why we are dealing with it; how we are dealing with it; areas to look out for in the field
It’s not an issue to NHDOT unless it’s EXCAVATED during construction or collected during maintenance operations. There are different levels of contaminated or impacted soils – Lightly Contaminated Soils is on the lower most end of that range.

4. Where is Mildly Contaminated/ Limited Reuse Soil?
Based on information collected by Division of Operations (Operations), the Bureau of Environment (BOE), and data identified from other state departments of transportation, roadside soils and street wastes have limited reuse potential due to the presence of metals and manmade contaminants related to transportation corridor uses.
Roadside soils and street wastes are soils generated from roadway runoff that end up in catch basins, drainage ditches, stormwater basins or collected during street sweeping efforts. These are soils that the Division of Operations is handling daily during roadway maintenance activities.
New Hampshire Department of Environmental Services (NHDES) classifies this impacted soil material as solid waste when excavated during construction or collected during maintenance operations. New Hampshire DOT creates significant amounts of this soil material during routine construction projects and maintenance efforts, and disposing of this material in solid waste facilities creates environmental impacts through the continuous landfill disposal of soil resources as well as significant financial impacts to the State.

5. LRS Design & Construction Goals
Haulers
Landfills
While this is a solid waste pyramid, the intent is the same for LRS – there is a hierarchy in what NHDOT should be striving for with LRS. Handling this material is expensive. The less material we handle, the less material required to be disposed of, the less financial impact and also better for the environment. We attacked this on all fronts within NHDOT – during design, construction and operations/maintence as a unified team goal of reducing the department’s impact of LRS. Reuse of non-clean soil verses hauling it to a landfill for cover, saves $35/CY.

6. LRS Project Extents*
LRS may be encountered in all topsoil adjacent to roadway surfaces on property under the control of NHDOT. In instances where topsoil is not present, LRS can be expected to be encountered in soil from the top of ground to a depth of six inches (6”).
*Disclaimer – “NHDOT’s understanding of the specified lateral and vertical limits adjacent to the roadways may be updated periodically, and shared with NHDES, based on published research and/or state-specific analytical data.”
New Hampshire DOT and NHDES drew upon research to work through a waiver process to allow efficient, prioritized, and restricted reuse of these materials within the transportation corridor from which they were produced. This statewide approach reduces unnecessary labor and consultant costs for both agencies while better protecting human health and the environment by promoting limited exposure, handling, transportation, and reuse of these materials.

7. If it can’t be used in a playground, it’s not clean.
This is the language we’ve had to use internally at NHDOT to get folks to understand the liability associated with our prior practices. The research project page listed contains a technical guidance document and a summary of all the state findings. We started this process with a survey and fourteen states provided valuable input with a shout out to Oregon for a lot of information. The remaining 35 states that are not currently addressing similarly contaminated soil, expressed interest in obtaining
additional information from New Hampshire as the development of LRS guidance progressed.
If it can’t be used in a playground, it’s not clean.

8. “NHDOT Research is the common thread of our Department.” Thank you!