Transcript Trace metal dispersal in the south branch of the Park

Trace metal dispersal in the south branch of the Park River watershed and its possible
impact
on
Connecticut
River
sediments,
Hartford,
CT
Geological Society of America 2009
Session No. 119-Booth #407
Victoria Doñé and Jonathan R. Gourley
Trinity College Environmental Science Program, Hartford, CT, [email protected]
Abstract
The Park River is an impaired urban river that flows through the city of
Hartford and surrounding municipalities and ultimately into the Connecticut
River. A major factor that contributes to the deterioration of the sediment
quality in the south branch of the Park River is the observed high
concentration of trace metals discharged directly into the stream. We
examine the downstream dispersal of trace metals Pb, Ni, Co, and Cu from
their point sources to determine to what extent trace metal contamination
impacts the sediments of the Connecticut River. The concentrations of
metals were analyzed using the ICP-OES. The online Right-to-Know
Network was also used to determine the historical amounts of reported
metal discharges into the Park River. In the Connecticut River (upstream of
the city of Hartford), Pb concentrations range from approximately 1-29
ppm. In the Park River, the Pb concentrations range from 40-250 ppm and
suggest that the Park River sediment could be a significant source of
anthropogenic trace metals into the Connecticut River.
Discussion
Pb
Co
Cr
Introduction
The south branch of the river has had a history of waste disposal, as was
discussed by Dr. Gourley in his talk. More specifically these industries
include metal finishing, metal plating, aerospace industries, and firearms
manufacturing. Because of this, the purpose of my experiment was to find the
concentrations of trace metals in the sediment of the Park River and the
Connecticut River. From this I was able to observe whether the Park River
has any affect on the sediment quality of the Connecticut River. The specific
metals I analyzed include lead, copper, chromium, cadmium, cobalt, and zinc.
Using the sediment collected from last summer, this summer, and throughout
the semester, I compared the south branch of the Park River, and Connecticut
River and used the north branch of the Park River as the control to determine
whether there was evidence for the Park River having an effect on the water
quality of the Connecticut River.
Figure 1: This figure shows the lead concentrations across the
Park River watershed. There is an increasing trend from
upstream to downstream and there is a prominent spike in the
downstream section of the Trout Brook. The Park River seems
to not be having an effect on the CT River sediment because
these data points show a slight decreasing trend.
Figure 2: This graph shows the cobalt concentrations across the
Park River watershed. There is an increasing trend from upstream
to downstream with a peak in the Trout Brook section. Also, the CT
River values start at a higher concentration (relative to the Park
River concentrations) and again do not seem to be affected by the
Park River sediments.
Figure 3: This figure shows the chromium concentrations
across the Park River watershed. This graph also shows a
positive correlation between distance downstream and
increasing chromium concentrations. There are two
prominent spikes in the south branch, specifically in the Piper
Brook and Trout Brook tributaries. The Park River doesn’t
not seem to be affecting the sediment quality of the CT River
because there is no change between the upstream and
downstream sites.
As is shown in Figures 1-6, there are elevated concentrations of heavy metals
present in the south branch of the Park River watershed. The problematic areas
(the spikes in the graphs) seem to be occurring in the same places along the
south branch. These specific places are two if the most downstream sections in
both the Piper Brook and the Trout Brook. As can be seen in Map 1, there is a
great concentration of industries along the banks of the Trout Brook and close to
the Piper Brook. Besides some auto repair companies, the bulk of the industries
are metal plating or metal finishing companies. According to the Right-to-Know
Network, these industries have been dumping metals like lead, chromium, and
copper into the river for at least 20 years. This is problematic because the metals
seem to be settling out close to their sources which makes this stretch of the
river unhealthy While this is good in some ways (the metals are not making their
way to the CT River), it is very detrimental to the health of this stream where
trout used to be abundant. Also, these concentrations, if present in the water,
would be absolutely lethal to any living organism.
Conclusions
•More sediment collection at other sites, especially on the CT River, is
necessary to make a more in-depth analysis.
•It would also be important to take a closer look at where the spikes are
occurring in the data (certain sections of Piper Brook and Trout Brook).
•The next step would then be to determine how readily available these metals
are to the biota and the possible effects on human health.
Methods
Sediment was collected at each site by wet-sieving it through a 45 µm
filter and into a polyethylene bottle washed with 5% hydrochloric acid.
The sediment was then dried out in an oven at a constant temperature of
60 C. The sediment was then weighed into 0.5 g aliquots and digested in
5% hydrochloric acid for two hours. The samples were then run through
the ICP-OES. This method was followed as was laid out in Giddings et
al. (2000).
Cd
Zn
References
•Giddings, M. I. (2001). Trace-Metal Concentrations in Sediment and Water
•Hou, A., DeLaune, R. D., Tan, M., Reams, M., & Laws, E. (2009). Toxic
Elements in Aquatic Sediments: Distinguishing Natural Variability from
Anthropogenic Effects. Water, Air & Soil Pollution , 179-191.
•Kauffman, G. J., & Belden, A. C. (2009). Water Quality Trends (1970 to 2005)
Along Delaware Streams in the Delaware and Chesapeake Bay Watersheds,
USA. Water, Air & Soil Pollution .
•Miller, J. R., & Miller, S. M. (2007). Contaminated Rivers. Dordrecht:
Springer.
•Right-to-Know Network. (2008, September 22). TRI Facilities for West
Hartford, CT. Retrieved October 2, 2009, from Right-to-Know Network:
http://www.rtknet.org/db/tri/tri.php?city=west+hartford&state=ct&dbtype=C&rs
ei=y&sortp=D&detail=-1&datype=T&reptype=f&reporting_year=&submit=GO
Results
Figures 1-6 show the concentrations of trace metals across the Park
River Watershed. The data is graphed across the watershed from
upstream to downstream. The CT River site graphed before the Park
River data is located above the Park River outflow and the other is
located under the outflow. The blue circles represent the north branch
of the Park River which are used as the control. The orange diamonds
represent the south branch of the Park River where the highest
concentration of industries and impervious surfaces are located. The
green squares signify the levels of trace metals in the Connecticut
River. The purple and red boxes represent different areas in the
watershed, as is shown in Map 1. The purple box is a part of the
Piper Brook and the red box is in Trout Brook.
Figure 4: This figure portrays the cadmium concentrations
across the Park River watershed as well as CT River
concentrations. There is a clear spike in cadmium levels in
the lower section of the Trout Brook where the highest
concentration of industries is located and also in the Piper
Brook.
Map 2: This map shows the specific peaks highlighted in figures 1-6. The red contains
the lowest section of the Trout Brook and the purple contains the lowest section of the
Piper Brook.
Figure 6: Graphed in this figure are the concentrations of zinc
across the Park River watershed and into the CT River. There
s an increasing trend from downstream to upstream with a
significant spike in concentrations located in the Piper Brook.
The CT River concentrations do not change much which
suggests that the south branch has no effect on the it in terms of
sediment quality.
Cu
Map 1: This map shows the leachate discharges (represented by the red circles) within the
Park River watershed. There is a high concentration of discharges located in the most
downstream sections of the Trout Brook and Piper Brook.
Photograph by Nathan Sell
Photograph by Nathan Sell
Picture 1: This is a picture of a site on the south branch of the Park River . There is barely any
vegetation growing over the stream and it has been channelized.
Picture 2: This is a site along the north branch of the Park River. There are anthropogenic influences
present and is more isolated than the site shown in picture 1.
Figure 5: This figure shows the copper concentrations from
upstream to downstream in the Park River watershed as well
as two CT River sites. There is a clear increasing trend with a
high spike located in the Piper Brook tributary of the south
branch of the Park River. The CT River values have a very
slight decreasing trend, with the Park River having no obvious
effect on its sediment quality.
Acknowledgments
I would like to thank Trinity Faculty Research Committee for the grants to facilitate my
research
.