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Screening tool helps protect streams, wetlands, homes from landfill risks

June 30, 2015, Lawrenceville, NJ – A new screening tool to assess the potential risk posed by
contaminated ground water moving from landfills to nearby streams,
wetlands and residences has been developed by the U.S. Geological Survey
and the New Jersey Pinelands Commission.

June 30, 2015, Lawrenceville, NJ – A new screening tool to assess the potential risk posed by
contaminated ground water moving from landfills to nearby streams,
wetlands and residences has been developed by the U.S. Geological Survey
and the New Jersey Pinelands Commission.

The recently published article in Waste Management Journal presents the innovative method to assign "levels of concern" to landfills based on a new modeling method, the USGS said in a news release.

The tool uses monitoring well and hydrologic data, physical
characteristics of the landfill (or other point source) and chemical
properties of the contaminant(s) to estimate ground water contaminant
concentrations at receptor locations.

"The method is suitable for a screening-level assessment of the risk
posed by a landfill or other contaminant point source, and can be used
by regulators and managers using basic spreadsheets." said Ron Baker, a
hydrologist with the U.S. Geological Survey and lead author of the
study. "This cost-saving approach enables regulators to make more
informed decisions as to the need for additional monitoring, a more
comprehensive modeling effort, or engineered remediation solutions."

The application of this screening tool was demonstrated by assessing
level-of-concern categories (high, moderate or low) to 30 closed,
uncapped or uncovered landfills in the New Jersey Pinelands National
Reserve, where there may be economic and environmental incentives to
redevelop. Caps do not destroy or remove contaminants, but instead
isolates them and keep them in place to avoid the spread of
contamination. Caps also prevent people and wildlife from coming in
contact with contaminants.

"This is a valuable tool for scientists and regulators because it
provides an economical approach to categorize the relative risks of
contaminant sources to nearby human and ecological systems," said Rick
Kropp, director of the USGS New Jersey Water Science Center.

Groundwater-quality data are collected at many landfills, but those
data alone are insufficient for deciding whether to take no action,
conduct further monitoring, install engineering controls, or cap a
landfill.

Landfills that pose no threat of ground water contaminants leaking to
nearby receptors, such as rivers, streams, and residences, may be
exempted from further consideration. At landfills where the screening
tool predicts the movement of contaminants of concern, such as nitrate,
benzene or mercury towards receptors in concentrations exceeding
regulatory standards may require additional monitoring and/or
engineering controls.

"The development and implementation of the screening-level model will
allow the Pinelands Commission’s staff to prioritize landfills in need
of remedial action and to bring those prioritized landfills to the
attention of the host municipalities," said Nancy Wittenberg, executive director of the Pinelands Commission. "It will also ensure that remedial
actions are commensurate with site specific considerations and hasten
approval of environmentally-appropriate, beneficial reuses of select
sites, such as the proposed installation of photovoltaic arrays at a
grid-accessible closed landfill site in the New Jersey Pinelands."

Beginning in 2016, the Pinelands Commission will advise those
municipalities in which a landfill with a high or moderate level of
concern is located of the results of the USGS’s screening level
assessment, for local followup. Host municipalities with landfills that
were categorized as representing a low level of concern will be
encouraged to meet with the Commission to finalize the closure status of
their landfills.