This document summarizes a study on microbial metal cycling and bioaccumulation in roadside soils and streams. The study aims to establish relationships between urbanization and pollutant concentrations in a local stream ecosystem. Researchers analyzed metal concentrations in insects, soils, and sediments from different zones of a creek. They also investigated microbial oxidation and reduction of antimony species from roadside soils and isolated bacterial strains to study metabolic pathways. Preliminary results found higher arsenic and lead levels in downstream insects and trace antimony reduction by soils microbes. The study provides background on metal pollution impacts and aims to further examine seasonal shifts and microbial antimony processing.

1. Microbial Metal Cycling and Bioaccumulation in Roadside
Soils and Streams
Graham Kilduff1, Joseph Visone1, Connor Daniel2
Meghan Dovick1, Matthew Lundquist2 , Dr. Thomas R. Kulp1, Dr. Weixing Zhu2
Binghamton University Departments of 1Geological Sciences and 2Biological Sciences
Stream and soil ecology are sensitive to
environmental changes and contamination. Soils and
streams adjacent to roadways are subject to high inputs of
rock salt due to the winterization of roads in the
Northeast. The urbanization of land adjacent to streams
and soils can also subject these environments to inputs of
anthropogenic contaminants (De Jonge et al 2014). Metals
and metalloids can be toxic and detrimental to biologic life
and ecological processes. Bioaccumulation of metal
contaminants by macroinvertebrates have been observed
in highly contaminated zones (Telford et al 2009).
Macroinvertebrates are of particular interest because
their community health represents a valuable indicator of
stream health.
Many ecologic processes are influenced by
microbial communities including: nitrogen fixation,
decomposition of organic matter, soil respiration, and
cycling of harmful contaminants. Cycling of metal
pollutants is of particular interest in this study. Microbes
can preferentially oxidize or reduce metals and metalloids
via autotrophic, heterotrophic, or detoxification pathways.
Antimony (Sb) is a toxic metalloid in the same group as
arsenic. Little work has been done on areas with trace
amounts of antimony contamination. It is unclear how
widespread the ability to oxidize and reduce this toxic
metalloid is, or how salinity affects these processes.
Methods
Results
Conclusions
Future Work
References
Acknowledgements
Introduction
Goals
• Establish a relationship between
urbanization and concentrations of
common urban pollutants in a local
stream ecosystem
• Determine concentration of urban
pollutants in insects, stream bank soils,
and stream sediments
• Elicit microbial oxidation and reduction
of antimony species from roadside soils
• Isolate microbial strains to determine
metabolic pathways and phylogeny
•Microbes from soils with trace amounts of Sb(III)
were able to tolerate and possibly grow off of
Sb(III) at higher concentrations
•Effect of increased salinity can not be
determined at this point
•Analysis of stream bank soil, stream sediment,
and water indicated safe levels of metal
concentration in all three sampling zones
•Significant differences were noted between
upstream and downstream zone insects in
arsenic and lead concentration (p values: As=
.013, Pb= .0048, confidence interval 95%)
•Relationship between insect metal
bioaccumulation and metal concentration of
adjacent soil and sediment is inconclusive.
Stream Ecology
• Heptageniid individuals were collected from three
stream zones (n>30 each zone) of varying urban
disturbance in Apalachin Creek, Apalachin, NY.
• Streambank soil, channel sediment, and water samples
were also collected
• Insects from stream sites underwent acid digestion
procedures for ICP-OES analysis, and then analyzed for
concentration of common urban pollutants and metals
Geomicrobiology
• Aerobic and Anaerobic microcosms were prepared
using soil samples and artificial freshwater media
• Aerobic microcosms were amended to 0.25mM Sb(III)
• Anaerobic microcosms were amended to 0.25mM
Sb(V) and 0.25mM Lactate
• Sb(V) concentration was tracked using Ion
Chromatography(IC), while Sb(III) and lactate
concentrations were tracked using High Pressure Liquid
Chromatography (HPLC)
• Once microbes were diluted away from sediment
fluorescent microscopy can be used to determine cell
density
Discussion
Geomicrobiology
• Soluble antimony potassium tartrate was used
as a Sb(III) source
• Sb(III) oxidation was observed in isolate
cultures with antimony potassium tartrate
• The presence of organic tartrate convolutes
possible metabolic pathways
• Sb(V) reduction in anoxic conditions yielded
inconclusive results
• Culturing microbes in high salinity ran into
problems with analytical measurements
Ecology
• Previous research has found that
macroinvertebrates, including family
Heptageniid, bioaccumulate metal pollutants
in highly contaminated areas (Telford 2009).
• Our previous HHMI work has shown that
sodium concentrations decrease rapidly with
increasing distance from roadsides
• Metals in stream bank soil and sediment
represent a potential pathway for entry into
stream water and insects
•Test different inorganic sources of Sb(III):
SbCl3, SbO3
•Sequence isolated Sb(III) oxidizer
•Work out a way to measure antimony in high
salinity solutions
•Establish seasonal shifts in bioaccumulation
of macroinvertebrates
We would like to thank Dave Collins, All faculty
and graduate mentors, and the BU-HHMI
program coordinators
0
20
40
60
80
100
120
140
160
Downstream Zone Midstream Zone Upstream Zone
SodiumConcentration(ppb)
Sodium Concentration in Stream Soil and
Sediment
Sodium
Concentration
In Stream soil
(ppm)
Sodium
Concentration
in Stream
Sediment (ppm)
0
2
4
6
8
10
12
Downstream zone Midstream Zone Upstream Zone
AverageppmPb,ASinsectbiomass
Concentration of Lead and Arsenic in
Heptageniid, Apalachin Creek
Average
Concentration of
Arsenic (As) in
stream insects
(ppm)
Average
Concentration of
Lead in stream
insects (ppm)
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De Jonge, Maarten; S. Lofts, L. Bervoets, R. Blust. “Relating Metal Exposure and chemical speciation to trace metal accumulation in aquatic insects under
natural field conditions”. Science of the Total Environment, 2014.
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Kulp, T. R., et al. "Effects of imposed salinity gradients on dissimilatory arsenate reduction, sulfate reduction, and other microbial processes in sediments from
two California soda lakes." Applied and environmental microbiology 73.16 (2007): 5130-5137.
Kulp, Thomas R., et al. "Microbiological reduction of Sb (V) in anoxic freshwater sediments." Environmental science & technology 48.1 (2013): 218-226.
Oremland, Ronald SEcosystem.” The Bulletin of the New Jersey Academy of Science. 56.2 (2011): 9-1., et al. "A microbial arsenic cycle in a salt-saturated,
extreme environment." Science 308.5726 (2005): 1305-1308.
Scott, Timothy, Stephanie Craig, and Weixing Zhu. "The Effects of Simulated Nitrate and Salt Deposition on Nitrogen Mineralization And Soil Chemistry In a
Roadside 1. Print.
Telford, K, Maher, W, Krikowa, F et al 2009, 'Bioaccumulation of antimony and arsenic in a highly contaminated stream adjacent to the Hillgrove Mine, NSW,
Australia', Environmental Chemistry (2009), vol. 6, no. 2, pp. 133-143.
Upstream Zone
Midstream Zone Downstream Zone
0
2
4
6
8
10
12
Downstream
Sediment
Midstream Sediment Upstream Sediment
concentration(ppb)
Arsenic and Lead Concentration in Stream
Sediment
Arsenic
Concentration,
stream
sediment
Lead
Concentration,
stream
sediment
Figure 1. Lead and arsenic concentrations showed an
observable increase between upstream and downstream
environments.
Increases were not statistically significant among the 3 groups
(p values: As = .0508, Pb= .0778, confidence interval > 95%)
Figure 2. Sodium concentrations did not vary between up and
downstream environments. This is unexpected when
considering varying riparian zone coverage between zones.
Figure 4. Weak correlation between lead concentrations and
stream location. Arsenic concentration is elevated downstream,
but small sample size limits statistical significance.
Figure 3. Stream sampling sites
Figures 5 and 6. Graph
showing Sb(III)
decreasing in live
cultures, but not in
killed cultures.
Figure 7. The isolated RT Sb(III) strain has growth when compared to
a no Sb(III) control.