Real World Project Presentation

Report
Heavy Metal
Concentrations in Tyler Run
Creek Water and Sediment
Olivia Yaple and Sara Wing
Background
Water and sediment contamination is
important to study due to its potential
adverse affects on public water supply quality
and aquatic life1
Cd in particular can permeate calcium channels
of aquatic vegetation and disrupt the plant
water status2
Background, Cont.
Cd, Pb, Cu, and Zn are heavy metals
commonly found in water and sediment
samples that can reach toxic levels3
These heavy metals can precipitate in an
aquatic system and deposit in sediment,
or end up there via sedimentation4
Background, Cont.
ICP and AA are both used to determine metal
concentrations in aqueous solutions
EPA freshwater quality recommendations:5
Metal
Concentration Limit (ppm)
Cd
0.002
Pb
0.065
Cu
0.00145
Zn
0.120
Hypotheses
Water from farther downstream would have higher
concentrations of all metals while farther upstream
would have lower concentrations.
Sediment from farther downstream would have
higher metal concentrations than farther upstream
Sediment metal concentrations would be higher than
water metal concentrations.
Method
Water samples were collected from Tyler Run creek at 10
foot and 50 foot increments upstream and downstream of
the ford
Sediment samples were collected from the same area and
extracted
Samples were analyzed using ICP and AA
Extraction Method
A funnel filled with filter paper was filled with
1.5 cm of sediment and let sit until dry
The dry sample was washed twice with 5 ml
quantities of 0.1M HNO₃ and let dry after each
wash. The filtrate was collected in 100 ml
volumetric flasks
The filtrate was diluted to 100 ml using
deionized water therefore all found
concentrations were 10 times less than actual
concentration
Standards
5 ppm, 10 ppm, 15 ppm, and 20 ppm standards of
Cd, Pb, Cu, and Zn were prepared via the
following dilution method:
10 ppm = 1 ml of 1000 ppm stock solution
100 ml DI water
• ICP used standards containing all metals
• AA used separate standards for each metal
Method, Continued
For both instruments, the run order was:
1) Blank
2) 5ppm standard
3) 10ppm standard
4) 15ppm standard
5) 20ppm standard
6) Water 50 ft downstream
7) Water 10 ft downstream
8) Water 10 ft upstream
9) Water 50 ft upstream
10) Sediment 50 ft downstream
11) Sediment 10 ft downstream
12) Sediment 10 ft upstream
13) Sediment 50 ft upstream
14) Spiked sample
Proving the Method
Using the spiked samples’ results, the method
was proved
For ICP, the sample of 10 ft downstream water
was spiked with 25 ppm Pb. The results showed
24.253 ppm.
24.253 ppm x 100 % = 97.012 % recovery
25 ppm
Proving the Method, Cont.
• For AA:
Sample
Used
Spike Conc.
Resulting
Conc.
Calculation
Percent
Recovery
Cd
10 ft upstream
water
20 ppm
19.45 ppm
(Resulting/Spike
d Conc.) x 100%
97.25
Pb
10 ft
downstream
water
25 ppm
22.66 ppm
(Resulting/Spike
d Conc.) x 100%
Cu
10 ft
downstream
water
20 ppm
21.41 ppm
(Resulting/Spike
d Conc.) x 100%
Zn
50 ft
downstream
water
18.14 ppm
(Resulting/Spike
d Conc.) x 100%
20 ppm
90.64
107.05
90.70
Proving the Method, Cont.
Based on the high percent recoveries for both ICP
and AA, we postulate that both instruments were
detecting all four metal concentrations, though
the AA could not detect the metal concentrations
in the samples
Therefore, all results reported are based on ICP
data
Results
Sample
Cd
Concentration
(ppm)
Pb
Concentration
(ppm)
Cu
Concentration
(ppm)
Zn
Concentration
(ppm)
Water 50 ft
downstream
0.0723*
0.0624
0.3144*
0.0836
Water 10 ft
downstream
0.0245*
0.0458
-0.0109
0.0247
Water 10 ft
upstream
0.01104*
0.3175*
-0.0193
0.0078
Water 50 ft
upstream
0.0055*
0.0373
-0.0198
0.00033
Sediment 50 ft
downstream
0.662*
0.671*
0.234*
0.572*
Sediment 10 ft
downstream
0.290*
1.5593*
0.895*
0.269*
Sediment 10 ft
upstream
0.089*
1.3310*
0.143*
0.254*
Sediment 50 ft
upstream
0.044*
0.651*
-0.061
0.076
*denotes a metal concentration in excess of the EPA recommended limits
Conclusions
Results showed that sediment samples
overall had much higher Cd, Pb, Cu, and Zn
concentrations than water samples
For sediment samples, farther downstream
samples had the highest metal
concentrations
For water samples, Cd had the highest
concentrations downstream, Zn showed the
same pattern, but was not over the EPA limit.
Discussion
ICP Cu data provided some negative values,
these are explained by the Cu concentrations
being below the detectable limit of 0.002
ppm5
Possible sources of error include but are not
limited to:
skewed calibration curves
Non-standardized sample procurement
Many samples contained heavy metal
concentrations close to the detection limit
1Saygi,
References
Y.; Yiğit, S. A. Heavy metal concentrations in Yeniçağa
Lake and its potential sources: Soil, water, sediment, and
plankton. Environ. Monit. Assess. 2012, 184, 1379-1389.
2Perfus-Barbeoch,
C.; Leonhardt, N.; Vavasseur, A.; Forestier, C.
Heavy metal toxicity: Cadmium permeates through calcium
channels and distrubs the plant water status. Plan. Jour. 2002,
32(4), 539-548.
3Filgueiras,
A. V.; Lavilla, I.; Bendocho, C. Chemical sequential
extractions for metal partitioning in environmental solid
samples. J. Environ. Monit. 2002, 4, 823-857.
4Avil-Peréz,
P.; Balcázar, M.; Zarazia-Ortega, G.; Barceló-Quintal,
I.; Díaz-Delgado, C. Heavy metal concentrations in water and
bottom sediments of a Mexican reservoir. Sci. of the Tot.
Environ. 1999, 234(1-3), 185-196.
5United
State Environmental Protection Agency. National
Recommended Water Quality Criteria.
http://water.epa.gov/scitech/swquidance/standards/current/inde
x.cfm (accessed April 25, 2012).

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