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FY 2000 ABSTRACTS
EFFECTS OF BIOSOLIDS ON GROUNDWATER QUALITY
Principal Investigators: Dr. William
McDowell, University of New Hampshire
Descriptors: biosolids, land application, groundwater, nitrate.
Problem and Research Objectives:
Beneficial re-use of residuals, such as biosolids and short paper
fiber, has become an increasingly important topic in both environmental
policy and science over the past decade. These materials, which are
a natural by-product of waste management, are becoming a significant
disposal problem. Reclamation activities, such as those at abandoned
gravel pits, provide a way for these secondary products to be recycled
back into the environment. However, the same attributes that make
this material valuable as an organic material, also may cause deleterious
effects to groundwater without proper management and monitoring.
Excessively high nitrogen content in biosolids may lead to nitrate
concentrations in groundwater that exceed EPA allowable limits and
lead to harmful environmental and human health effects.
The State of New Hampshire along with the entire New England region
have been actively trying to enact policies dealing with the use
of residuals specifically for reclamation activities. However, environmental
policy and effective management practices are extremely difficult
to develop without the aid of comprehensive scientific studies that
examine the impacts of these activities on the ecosystem.
The purpose of this project is to continue a groundwater monitoring
demonstration project at a reclamation site utilizing residuals regulated
by Env-Ws 800. Specifically, the project assesses the impact of residual
application on nitrogen concentrations (nitrate, ammonium, and dissolved
organic N) and dissolved organic carbon in groundwater at a topsoil
manufacturing site in New Hampshire. This site uses biosolids and/or
short paper fiber (SPF) to reclaim (revegetate) a former gravel pit
and manufacture topsoil. The primary goal of the project is to demonstrate
whether current management and application practices are sufficient
to protect groundwater from contamination with NO 3 -N and other
forms of dissolved nitrogen. A secondary goal of the project is to
assess levels of trace metals in groundwater at this reclamation
site. In assessing these goals we aim to identify ways to improve
best management practices (BMPs) and protect groundwater while continuing
to provide a beneficial use for this nutrient-rich material.
Principal Findings and Significance:
The monitoring demonstration at this biosolids application site
in Hooksett, NH has produced several key findings. First, there are
significant increases in average NO 3 -N concentrations in groundwater
when wells beneath biosolids treatment areas are compared to control
and upgradient wells at the site. However, the concentrations of
NO 3 -N in groundwater both within and downgradient from the biosolids
treatment area show high spatial variability. This suggests that
NO 3 -N contamination has not resulted from the relatively uniform
biosolids applications, but rather has resulted from non-uniform
stockpiling at the site. Based on the management history of the site
and the location of areas of high NO 3 -N concentrations in groundwater
we are fairly certain that this stockpiling activity has led to deleterious
effects on groundwater.
We believe that gravel pit management practices can lead to nitrogen
saturation of soils (Aber et al. 1989), a condition in which soil
microbes and plants can no longer utilize available N in a predictable
or effective way, resulting in contamination of groundwater with
nitrogen. This was most likely the case at the Hooksett site where
past stockpiling and application activity may have led to an inability
of the soil to utilize the available N provided by the biomix application
in October of 1999. Although available nitrogen appears to be high,
the available carbon at the site appears to be quite low. This lack
of available carbon as an energy source for microbial processing
has led to increased levels of nitrification causing an increase
in NO 3 -N production and a subsequent leaching of NO 3 -N to the
groundwater.
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LAKES LAY MONITORING PROGRAM
Principal Investigators: Dr. Jeffrey
Schloss, University of New Hampshire
Descriptors: lakes, nutrients, long-term dataset, water quality
Problem and Research Objectives:
The Lakes Lay Monitoring Program is an ongoing effort between the
state of NH and the University of New Hampshire. The a 25 year history,
its objective is to provide a long-term assessment of water quality
in the state's lakes. Lakes are a critically important component
of the state's environmental and economic health. Tourism provides
a significant fraction of the state's economic base, and high water
quality drives much tourism activity. The ecological health of the
state is also tied to the health of its lakes. Lakes provide much
of the state's biodiversity as well as a quantitatively significant
fraction of the state's total aquatic habitat.
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STREAM CHEMISTRY AS AN INDEX OF SUSTAINABILITY IN THE COLLEGE
BROOK WATERSHED
Principal Investigators: Dr.
William McDowell, University of New Hampshire
Descriptors: water quality, land use, nutrients, sustainability
Problem and Research Objectives:
Stream chemistry reflects the physical, chemical, and biological
characteristics of a watershed. It is responsive to degradation or
restoration of the watershed's biotic functions; therefore the stream
chemistry reflects the ecology of the watershed. College Brook runs
through the heart of the University of New Hampshire campus and monitoring
of stream chemistry will provide an excellent means to assess the
sustainability of the campus.
Previous work on College Brook in 1991 showed that the University
was having a significant impact on water quality and the stream biota,
thus indicating that the campus could not be considered sustainable.
The UNH incinerator was causing high organic matter loading, resulting
in high biochemical oxygen demand (BOD) and low dissolved oxygen
(DO) in the stream. Other practices, such as washing of waste art
materials (slip, poster paint, etc.) into street drains near the
Service Building, were also impacting College Brook.
With the closing of the UNH incinerator, and heightened awareness
of College Brook on campus, water quality has likely improved. Sporadic
tests of water quality and characterization of benthic invertebrates
as part of class laboratory exercises suggested that it has. But
there has been no attempt to systematically monitor water quality
in College Brook, and this is what was needed to establish that ecological
conditions in the watershed have improved.
Principal Findings and Significance:
Analysis of the data from 2000 can be compared to the data from
1991 to establish if ecological restoration has occurred (sample
analysis from 2000 is not complete at this time, with anions, cations,
total dissolved nitrogen, and SiO 2 analysis still to be performed).
The completed analysis indicates that the ecological integrity of
the watershed has improved at sites that were sampled in both 1991
and 2000. Yearly averages show overall improvement of water quality
from 1991 to 2000 (Table1). DO has increased and BOD has decreased
at every site, indicating that the closing of the incinerator has
decreased organic matter loading. DOC has also decreased at every
site.
There has been an overall improvement of NH 4 , except at CB2 and
CB4, where there have been increases. There has been an overall improvement
in TSS as well, except at CB4, which has had a large increase. The
increase in both of these parameters at CB4 may indicate that the
placement of buildings over the stream has had a negative impact
that needs to be considered.
Further analysis is needed to determine the sustainability of the
UNH campus. Samples in 1991 were taken from February to September,
while samples in 2000 were taken from May to December. While comparisons
of samples between 1991 and 2000 taken at the same time of year show
that there has been improvement in water quality, the picture is
not as clear as the yearly averages indicate. There is much more
variability in the data when the time of year is taken into account.
A more complete sampling period is needed to determine the precise
amount of improvement at all sites within the watershed and sampling
has continued in 2001 to establish the ecological health of College
Brook.
Visit
the web site, which shows the progress of
the restoration, a complete description of the project (with pictures
of the sites), and completed data from the project.
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