Heavy Metal Concentrations in Tyler Run Creek Water and Sediment

coriandercultureMechanics

Feb 22, 2014 (2 years and 9 months ago)

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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 life
1

Cd in particular can permeate calcium channels
of aquatic vegetation and disrupt the plant
water status
2

Background, Cont.

Cd, Pb, Cu, and Zn are heavy metals
commonly found in water and sediment
samples that can reach toxic levels
3

These heavy metals can precipitate in an
aquatic system and deposit in sediment,
or end up there via sedimentation
4



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%


90.64

Cu

10 ft
downstream
water

20 ppm

21.41 ppm

(Resulting/Spike
d Conc.) x 100%

107.05

Zn

50 ft
downstream
water

20 ppm

18.14 ppm

(Resulting/Spike
d Conc.) x 100%


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
ppm
5

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

References

1
Saygi, 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.

2
Perfus
-
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.

3
Filgueiras, A. V.; Lavilla, I.; Bendocho, C.
Chemical sequential
extractions for metal partitioning in environmental solid
samples.
J. Environ. Monit.
2002
,
4
, 823
-
857.

4
Avil
-
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.

5
United State Environmental Protection Agency. National
Recommended Water Quality Criteria.
http://water.epa.gov/scitech/swquidance/standards/current/inde
x.cfm (accessed April 25, 2012).