METAL AND DDT BIOACCUMULATION AND BIOMARKER RESPONSES

OF THE TIGERFISH, HYDROCYNUS VITTATUS, FROM THE JOZINI DAM AND OKAVANGO RIVER.

Miss E. Fisher, Miss Liesel Whitlow, Prof. V. Wepener & Prof. N. Smit

INTRODUCTION

• Why tigerfish?• High trophic level

(Skelton 2001)• Robbers, minnows,

sardines (Skelton 2001)• Bioaccumulate and

biomagnify (Mhlanga 2000)

• Increasing human activity.• Little known about

bioaccumulation and biomarker responses in tigerfish (Mhlanga 2000; du Preez & Steyn 1991), biomarkers (Whitlow et al. 2008)

AIM: To compare bioaccumulation of heavy

metals and DDT in tigerfish from two systems of varying impacts.

To relate biomarker responses of tigerfish from these systems, and determine whether

or not tigerfish are being stressed as a result of exposure.

HYPOTHESIS Part 1:

Tigerfish from the Jozini Dam will have higher levels of heavy metals and DDT than tigerfish

from the Okavango River.

Part 2 Tigerfish from the Jozini Dam will exhibit more

stress than tigerfish from the Okavango River as a result of the greater influx of pollutants

into this system.

STUDY OBJECTIVES

To determine the environmental partitioning of heavy metals in the Jozini Dam and Okavango River.

To compare the concentrations of heavy metals and DDT in the muscle tissue of tigerfish from these ecosystems.

To compare biomarker responses between tigerfish from the different sites, and

to relate the biomarker responses to the metal and DDT bioaccumulation in the muscle tissue of tigerfish.

SITE SELECTION

tigerfish presence (Skelton 2001)

varying degrees of impacts

Jozini Dam: slightly impacted

Okavango River: relatively unimpacted

JOZINI DAM

Photos taken from DWAF(2004)

JOZINI DAM

The Phongolo river: east of Wakkerstroom

Jozini dam wall (1972).

2492 million m3 water.

DDT sprayings Current uses (DWAF

2004).

Jozini Dam: Tigerfish

OKAVANGO RIVER

http://wpcontent.answers.com/wikipedia/commons/thumb/7/72/Okavango_RiverSign.jpg/288px-Okavango_River_Sign.jpg

OKAVANGO RIVER The Okavango river

(McCarthny 2005; Wilk et al. 2006) 10km3 + 6km3 per annum 25000km2 permanent 80000km2 seasonal 170 000 tonnes 360 000 tonnes

Threats: Boro River (Ellery & McCarthy

1998)

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

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METHOD

SAMPLING Sediment & water

Acid washed polypropylene bottles

Tigerfish Caught Anesthetized &

Sacrificed Dissected Muscle frozen Biomarkers:

Hendrickson stabilization buffer

Liquid nitrogen

CONT. OF METHOD PROCESSING

Metals Dried Digestion ICP-MS ICP-OES

Pesticides Freeze dried GCMS (μg/g lipid)

Biomarkers AChE (Ellman et al. 1961)

LP (MDA) (Ohkawa et al. 1979; Uner et al.

2005)

CAT (Cohen et al. 1970)

http://www.wcaslab.com/images/icpms/plasma.jpg

CONT. OF METHOD

PC (Parvez & Raisuddin 2005; Levine et al. 1990; Fernandes

et al. 2008; Floor & Wetzel 1998)

Metallothioneins (Viarengo et al. 1997; Viarengo

et al. 1999; Atli & Canli 2008; Fernandes et al. 2008; Hubbard 2005)

CEA (de Coen & Janssen 1997; de Coen & Janssen 2003)

STATISTICAL ANALYSIS Unpaired Student t-Test PASW(18.0) Significance P<0.05

RESULTS AND DISCUSSIONSEDIMENT AND WATER COMPARISON

Cr Co Ni Cu Zn As Cd Pb0.000

0.001

0.002

0.003

0.004

0.0051

26

0.000

0.001

0.002

0.003

0.004

0.0051

26

Jozini waterJozini sediment

* * *

Jozini Metals

me

tal S

ed

[ ]

ug

/g

Me

tal w

ate

r [ ] 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

meta

l S

ed

[ ]

ug

/g

Meta

l wate

r [ ] ug

/mL

(Huntsman_Mapila et al. 2005; Huntsman Mapila et al. 2009)

RESULTS & DISCUSSIONMETALS: MUSCLE

Pongola Okavango0

2

4

6Al

Sites

Al (

g

/g d

ry w

eig

ht)

Pongola Okavango0.00

0.01

0.02

0.03

0.04

Sites

As

(g

/g d

ry w

eig

ht) As

Pongola Okavango0.000.010.020.030.040.050.060.070.080.090.100.11

Sites

Co

(

g/g

dry

we

igh

t)

Co

Pongola Okavango0.0

0.1

0.2

0.3

Sites

Cr

(

g/g

dry

wei

gh

t)

Cr

Pongola Okavango0.000.050.100.150.200.250.300.350.400.450.500.550.600.65

Sites

Pb

(g

/g d

ry w

eig

ht)

Pb

JoziniJoziniJozini

JoziniJozini

RESULTS & DISCUSSIONMETALS:MUSCLE

Coal mining and shales: Cu, Fe (Johnson et al. 2006; Huntsman Mapila et al. 2009)

Pongola Okavango0.0

0.1

0.2

0.3

0.4

0.5

0.6

*

Sites

Cu

(

g/g

dry

weig

ht)

Cu

Pongola Okavango0.00

0.05

0.10

0.15

*

Sites

Cd

(g

/g d

ry w

eig

ht)

Cd

Pongola Okavango0

25

50

75

100

*

Sites

Fe

(mg

/g d

ry w

eig

ht)

Fe

Jozini

Jozini Jozini

RESULTS & DISCUSSIONMETALS: MUSCLE

Pongola Okavango0.0

0.5

1.0

1.5

*

Sites

Mn

(

g/g

dry

wei

gh

t)

Mn

Pongola Okavango0

1

2

3

4

5

6

7

8

9

*

Sites

Zn

(g

/g d

ry w

eig

ht)

Zn

Pongola Okavango0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

*

Sites

Ni

(g

/g d

ry w

eig

ht)

Ni

(Sawula 2004)

Jozini Jozini

Jozini

DDT EXPOSURE

DDT TOTAL

Okavango Pongola0

5001000150020002500300035004000450050005500

*

Sites

gD

DT

/g L

ipid

Jozini

RESULTS & DISCUSSIONBIOMARKERS

BIOMARKERS OF OXIDATIVE STRESS

CAT

Okavango Pongola05

10152025303540455055

*

Sites

um

olH

2O2/

min

/mg

pro

t

PC

Okavango Pongola0

10

20

30

40

*

Sites

nm

ol

carb

on

yls/

mg

pro

t

LP

Okavango Pongola0.0

0.1

0.2

0.3

0.4

0.5

0.6

*

Sites

nm

ol/

mg

pro

t

Jozini

Jozini

Jozini

RESULTS & DISCUSSIONPARAMETERS OF CEA

Lipid

Okavango Pongola0

100200300400500600700800900

100011001200

*

Sites

J/g

Protein

Okavango Pongola0

500

1000

1500

*

Sites

J/g

Glucose

Okavango Pongola0

100

200

300

*

J/g

Sites

Jozini Jozini

Jozini

RESULTS & DISCUSSIONCont. of CEA Parameters

Ea

Okavango Pongola0

100200300400500600700800900

10001100120013001400

*

Sites

J/g

Ec

Okavango Pongola0

25

50

75

100

125

150

175

Sites

J/g

CEA

Okavango Pongola0

1000

2000

3000

*

Sites

J/g

Jozini Jozini

Jozini

Okavango

RESULTS & DISCUSSIONBiomarkers of effect

MT

Okavango Pongola0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

*

Sites

(nM

/mg

pro

t)

AChE

Okavango Pongola0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0.0040

0.0045

*

Sites

Ab

s/m

in/m

g p

rot

Jozini Jozini

CONCLUSIONHAVE WE ACCEPTED PART 1 OF OUR

HYPOTHESIS?

YES!

Tigerfish from the Jozini Dam are bioaccumulating higher levels of

pollutants, than tigerfish from the Okavango River.

CONCLUSIONHAVE WE ACCEPTED PART 2 OF OUR

HYPOTHESIS?

NO!

Tigerfish from the Jozini Dam are experiencing less oxidative stress than

tigerfish from the Okavango River, however they have greater responses to

exposure of toxicants.

POSSIBLE REASONS FOR STRESS

Okavango oxidative stress & lower CEA:

Barbel run Lotic environment

Jozini AChE & MT AChE: Carbamate pesticides, organophosphates, nerve

gases MT: Higher levels of metals: Cu & Cd

EXTRA CONSIDERATIONS

• NUTRIENTS• CATIONS• ANIONS• PHYSICAL WATER

PARAMETERS• GEOLOGY• SAMPLING TIME

ACKNOWLEDGEMENTSACKNOWLEDGEMENTS WATER RESOURCE COMISSION

(Resources) PROFESSOR V. WEPENER (Supervisor)

PROFESSOR N. SMIT (Co-supervisor)

MISS LIESEL WHITLOW (Data from the Okavango)

DR. H. VAN NIEKERK (SPEC-RAU)

MISS NATALIE DEGGER (Assistance with SPSS)

MR. KYLE MCHUGH (Sample Collection & Pictures)

MISS MICHELLE SOEKOE (Sample Collection)

MISS YOLANDI CLOETE (Sample Collection & other)

THANK YOU!