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This presentation was my presentation on some of my honours project which was a comparative assessment between tigerfish from the Jozini Dam and a reference site, the Okavango River
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University of Johannesburg Zoology Department
Metal bioaccumulation in Metal bioaccumulation in muscle tissue of tigerfishmuscle tissue of tigerfish
(Hydrocynus vittatus) (Hydrocynus vittatus) from from the Pongolapoort Dam and the Pongolapoort Dam and
Okavango RiverOkavango River
By: E. M FisherSupervisor: Prof. V. WepenerCo-Supervisor: Dr. N Smit
IntroductionIntroduction• tigerfish
• Declining populations (Skelton, 2001)
» Human impacts
» Biological
• Protected species (Government Gazette, 2008)
• High trophic level
• Commercially important (Skelton, 2001)
• Bioaccumulate and biomagnify (Mhlanga, 2000)
University of Johannesburg Zoology Department (McHugh,2009)
BioaccumulationBioaccumulation
• What is it? (Connell et al., 1999)
• What does it tell you?• Environmental exposure• Bioavailability• Biomagnification
• What doesn’t it tell you?• What the effects are.• Non-hazard determination
University of Johannesburg Zoology Department
(Gerber & McHugh, 2009)
University of Johannesburg Zoology Department
Pongolapoort DamPongolapoort Dam
Photos taken from DWAF(2004)
University of Johannesburg Zoology Department
Pongolapoort DamPongolapoort Dam
• The Phongolo river: east of Wakkerstroom
• Pongolapoort dam wall (1972).
• 2492 million m3 water.• DDT sprayings (1940). • Current uses (DWAF,2004).• Pongolapoort Dam: Tigerfish
http://flickr.com/photos/65196834@N00/2538492822http://www.prafrica.co.za/img/jpg/photos/pongola-dam.jpg
University of Johannesburg Zoology Department
Olifants riverOlifants river
http://www.dwaf.gov.za/iwqs/rhp/state_of_rivers/state_of_crocsabieolif_01/maps/olif_eco_600.jpg
University of Johannesburg Zoology Department
Cont. Olifants riverCont. Olifants river• Olifants river (du Preez
& Steyn, 1992).
• “mining, industrial and other related activities” (du Preez & Steyn, 1992)
http://images.travelpod.com/users/mattersdorff/1.1219433160.bird-glides-in-for-sunset-on-olifants-river.jpghttp://www.telegraph.co.uk/telegraph/multimedia/archive/00746/france-nuclear-404_746493c.jpg
University of Johannesburg Zoology Department
Okavango RiverOkavango River
http://na.unep.net/AfricaAtlas/AfricaAtlas/AtlasDownload/Maps/okavango_catchments.jpg
University of Johannesburg Zoology Department
Cont. Okavango RiverCont. Okavango River • The Okavango
river• Threats:
• Possible canalization
• Potential
development http://www.cfnews13.com/uploadedImages/Site_Content/Features/Kissimmee_River/Rest1.jpg
http://www.geog.ucl.ac.uk:8080/print-version/about-the-department/people/academics/martin-todd/accord/images/map2.jpg
QUESTION?QUESTION?
Are the metal concentrations in the muscle tissue of the tigerfish
reflecting environmental exposure to metals?
University of Johannesburg Zoology Department
University of Johannesburg Zoology Department
HypothesisHypothesisMetal concentrations in muscle
tissue of tigerfish in non-impacted areas will be lower
than those from impacted areas.
University of Johannesburg Zoology Department
AimAim
To determine whether metal concentrations in muscle tissue of
tigerfish in non-impacted areas will be lower than those from
impacted areas.
University of Johannesburg Zoology Department
ObjectivesObjectives• To compare metal concentrations in
the muscle tissue of tigerfish in the Pongolapoort Dam to studies in the Okavango Delta; Botswana, and the Olifant's river; Kruger National Park, South Africa.
• To compare muscle tissue concentrations to those found in sediment and water to determine bioavailability
University of Johannesburg Zoology Department
The StudyThe Study
• Historical study: Olifants (du Preez & Steyn, 1992)
• Study: Okavango (Whitlow,2008)• Pongolapoort
Dam (2009)
(Van der Bank & Smit ,2007. as cited by Whitlow, 2008)
SITE 5
Olifants site
University of Johannesburg Zoology Department
MethodMethod
• SAMPLING• Caught• Anesthetized & Sacrificed• Dissected• Frozen
• PROCESSING• Drying• Digestion
• Fly, bait and artificial lures.• Anesthetic: Clove Oil in ethanol and sacrificed• Portions of axial muscle removed. • Muscle tissue frozen and taken back to the lab.
(Gerber & McHugh, 2009)
University of Johannesburg Zoology Department
Cont. of MethodCont. of Method
• ANALYSIS• ICP-OES• ICP-MS
• STATISTICAL ANALYSIS• Unpaired Student t-Test• SPSS (15.0)• Significance P<0.05
http://www.wcaslab.com/images/icpms/plasma.jpg
RESULTS AND DISUSSIONSediment and Water Comparison
Cr Co Ni Cu Zn As Cd Pb0.000
0.001
0.002
0.003
0.004
0.0051
26
Pongola water
0.000
0.001
0.002
0.003
0.004
0.0051
26Pongola sediment
* * *
Pongola Metals
met
al S
ed [
] u
g/g
Metal w
ater [ ] ug
/mL
Cr Co Ni Cu Zn As Cd Pb0.000
0.005
0.010
Okavango sedimentOkavango water
0.11.12.13.14.15.16.1
0.000
0.005
0.0100.11.12.13.14.15.16.1
* * *
Okavango Metals
met
al S
ed [
] u
g/g
Metal w
ater [ ] ug
/mL
•Olifant river water and sediment (Seymore, 1994)•Bioaccumulation dependent on water concentration (Connell et al., 1999)
Cr Ni Cu Zn Pb0
1
2
Olifants Sediment
Olifants Water
0
1
26
31
6
31
Olifants Metals
met
al S
ed [
] u
g/g
Metal w
ater [ ] ug
/mL
RESULTS AND DISCUSSIONWater comparison between sites
Cr Ni Cu Zn Pb0.00000.00010.00020.00030.00040.00050.0006
Pongola water
Okavango water
Olifants Water
0.0007
0.0107
0.04
1.04
Metals
met
al W
ater
[ ] u
g/m
L
0.0070.002
0.0001
0.003
0.002
Cu,Zn (Sawula,2004)
University of Johannesburg Zoology Department
Results & DiscussionResults & Discussion
• No statistical significant difference between sites for Al, As, Co and Cr.
• As (Huntsman-Mapila et al., 2006)
Pongola Okavango0.00.51.01.52.02.53.03.54.04.55.05.5
SitesAl
(
g/g
dry
wei
ght)
Pongola Okavango0.00
0.01
0.02
0.03
0.04
Sites
As (
g/
g dr
y we
ight
)
Pongola Okavango0.000.010.020.030.040.050.060.070.080.090.100.11
Sites
Co (
g/
g dr
y w
eigh
t)
Pongola Okavango0.0
0.1
0.2
0.3
SitesCr
(
g/g
dry
wei
ght)
University of Johannesburg Zoology Department
Cont. of DiscussionCont. of Discussion
• Much higher lead in Olifants than other sites
• In water, Pb was higher in Okavango than Pongola, and highest in Olifants Pongola Okavango Olifants
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
Sites
Pb
(g/
g dr
y w
eigh
t)
University of Johannesburg Zoology Department
Cont. of DiscussionCont. of Discussion• There is a statistically
significant difference between sites for Cu,Cd and Fe.
• In water, Cu was higher in Okavango than Pongola, and highest in Olifants.
• Coal mining and shales: Cu, Fe (Johnson et al., 2006)
Pongola Okavango Olifants0.0
2.5
5.0
7.5
*
Sites
Cu
(g
/g d
ry w
eig
ht)
Pongola Okavango Olifants0
1
2
3
*
Sites
Cd
(g
/g d
ry w
eig
ht)
Pongola Okavango Olifants0
25
50
75
100
*
Sites
Fe (
g/g
dry
weig
ht)
University of Johannesburg Zoology Department
Cont. of DiscussionCont. of Discussion• There is a statistically
significant difference between sites for Mn (Sawula, 2004), Zn (Sawula, 2004) and Ni (Sawula, 2004).
• In water, Zn higher in Okavango than Pongola,and highest in Olifants
• In water, Ni was higher in Pongola than Okavango, and highest in Olifants
Pongola Okavango Olifants0.0
0.5
1.0
1.5
2.0
2.5
*
Sites
Mn
(g
/g d
ry w
eig
ht)
Pongola Okavango Olifants0
5
10
15
20
*
Sites
Zn(
g/g
dry
weig
ht)
Pongola Okavango Olifants0.0
2.5
5.0
7.5
10.0
*
Sites
Ni
(g
/g d
ry w
eig
ht)
University of Johannesburg Zoology Department
ConclusionConclusionIS THE HYPOTHESIS SUPPORTED?
YES!ALTHOUGH HUMAN IMPACTED AREAS
GENERALLY HAVE HIGHER METAL CONCENTRATIONS THAN NON-
IMPACTED AREAS, OTHER FACTORS INFLUENCE THE OCCURANCE OF
METALS.
OTHER FACTORS NEED TO OTHER FACTORS NEED TO BE TAKEN INTO ACCOUNTBE TAKEN INTO ACCOUNT
• SUCH AS– GEOLOGY– FISH ADAPTATION TO TOXICANTS– pH, WATER HARDNESS,
CONDUCTIVITY,TURBIDITY– OTHER IONS AND METALS IN WATER– SEQUESTRATION OF HEAVY METALS IN
OTHER AREAS THAN MUSCLE
University of Johannesburg Zoology Department
University of Johannesburg Zoology Department
RECOMMENDATIONSRECOMMENDATIONS
• More recent studies.
• For future studies it is recommended that a sample size of at least 20 fish is used.
• Water and sediment properties should be taken into account
• Geology of the area must be taken into account
• Take into account adaptation of fish to the toxicant
University of Johannesburg Zoology Department
ACKNOWLEDGEMENTSACKNOWLEDGEMENTS
• PROFESSOR V. WEPENER (Supervisor)
• DR. N. SMIT (Co-supervisor)
• DR. H. VAN NIEKERK (SPEC-RAU)
• MISS LIESEL WHITLOW (Data from the Okavango)
• MISS NATALIE DEGGER (Assistance with SPSS)
• MR. KYLE MCHUGH (Sample Collection & Pictures)
• MS. MICHELLE SOEKOE (Sample Collection)
• MS. YOLANDI CLOETE (Sample Collection & other)
• UNIVERSITY OF JOHANNESBURG ZOOLOGY DEPARTMENT ( Moral Support & Resources)
University of Johannesburg Zoology Department
THANK YOU!THANK YOU!