Levels of heavy metal uptake by Abelmoschus esculentus and Buchole dactyloides grown in a damaged dry-battery disposal site in the wet zone of Sri Lanka- S. Weerasinghe

Levels of heavy metal uptake by Levels of heavy metal uptake by Abelmoschus esculentus Abelmoschus esculentus and and Buchole Buchole dactyloides dactyloides grown in a damaged dry-grown in a damaged dry-

battery disposal site in the wet zone of battery disposal site in the wet zone of Sri LankaSri Lanka

*Weerasinghe, W. P. S. J., *Dayawansa, P. N. and **Perera, R. P

*Department of Zoology, University of Colombo**Department of Chemistry, University of Colombo

IntroductionIntroduction Heavy metals exist in natural environment in Heavy metals exist in natural environment in

varying concentrations and they are naturally varying concentrations and they are naturally released into environment through different released into environment through different natural events while many adverse human natural events while many adverse human activities enhance these natural activities enhance these natural concentrations. concentrations.

Increased heavy metal concentrations and Increased heavy metal concentrations and heavy metal toxicity are major environmental heavy metal toxicity are major environmental issues that we are facing today. issues that we are facing today.

Having the ability to bind various chemicals, Having the ability to bind various chemicals, Soil is a major reservoir of heavy metals in Soil is a major reservoir of heavy metals in the environment.the environment.

Heavy metals in soil can be readily entered Heavy metals in soil can be readily entered into plants which could lead to into plants which could lead to bioaccumulation and biomagnification bioaccumulation and biomagnification through food webs.through food webs.

Ultimately increased heavy metal levels Ultimately increased heavy metal levels result in many health disorders in animals result in many health disorders in animals and growth disorders in plants. and growth disorders in plants.

The study site was a dry cell battery The study site was a dry cell battery production factory owned land which was production factory owned land which was used to dump damaged dry cell batteries, used to dump damaged dry cell batteries, batteries with low voltages, production wastes batteries with low voltages, production wastes and common types of factory wastes.and common types of factory wastes.

The factory produces Zn – Carbon dry cell The factory produces Zn – Carbon dry cell batteries which uses Manganese, Zinc, batteries which uses Manganese, Zinc, Carbon, Iron, Tin and Acetylene black as the Carbon, Iron, Tin and Acetylene black as the major raw materials.major raw materials.

Cathode terminal

Brass top cover

Plastic/Metal cover

Plastic lidCarbon rod

Black mix

Coated separator (Gel/paper separator)

Zinc can

Label

Outer jacket

Bottom washer

Anode Terminal

Ground Layer

Disposed damaged dry cells

Loose soil layer (About 1m)

Laterite soil

Vegetation

The site was filled with a soil layer about 1m thick about one year ago

ObjectiveObjective

The objective of this study was to investigate The objective of this study was to investigate whether heavy metal concentrations in whether heavy metal concentrations in Buchole dactyloides Buchole dactyloides (Common Buffalo Grass) (Common Buffalo Grass) and and Abelmoschus esculentus Abelmoschus esculentus (Ladies’ fingers)(Ladies’ fingers) growing in a damaged dry cell dumping site growing in a damaged dry cell dumping site are greater than those grown in an are greater than those grown in an uncontaminated site.uncontaminated site.

Ladies’ fingers Ladies’ fingers Common buffalo grass Common buffalo grass

((Abelmoschus esculentusAbelmoschus esculentus) ) ((Buchole dactyloidesBuchole dactyloides) )

Leaves of two species of plants were collected from the Leaves of two species of plants were collected from the dumping site and a control site (located 2.5 Km away). dumping site and a control site (located 2.5 Km away).

Plant samples were air dried, oven dried and ashed in a Plant samples were air dried, oven dried and ashed in a muffle furnace. muffle furnace.

Heavy metal contents (Mn, Zn, Pb, Ni and Cd) of plant Heavy metal contents (Mn, Zn, Pb, Ni and Cd) of plant matter were analyzed using Atomic Absorption matter were analyzed using Atomic Absorption Spectrophotometer. Spectrophotometer.

MethodologyMethodology

Data AnalysisData Analysis

Heavy metal contents of test and control samples were compared using non-parametric statistical tests (Mann – Whitney U Test) (Minitab 15)

Plant matter in the dry battery dumping site Plant matter in the dry battery dumping site contained significant higher amount of Mn contained significant higher amount of Mn than that of the control site than that of the control site

(Mann Whitney U Test: P<0.05) (Mann Whitney U Test: P<0.05)

ResultsResults

Mn2+ concentrations of test and control samples of dicotyledonous

plant leaves samples

0

0.5

1

1.5

2

2.5

D1 D2 D3 D4 D5 D6

Sample number

Co

nc

en

tra

tio

n

(mg

/g) Test

Control

D1C D2C D3C D4C D5C D6C

Mn

Mn2+ concentrations of test and control samples of monocotyledonous plant leaves

samples

0

0.5

1

1.5

2

2.5

3

3.5

M1 M2 M3 M4 M5 M6

Sample number

Co

nce

ntr

atio

n (m

g/g

)

Test

Control

M1C M3CM2C M4C M5C M6C

Mn

Plant matter in the dry battery dumping site Plant matter in the dry battery dumping site contained significant higher amount of Zn contained significant higher amount of Zn than that of the control site than that of the control site

(Mann Whitney U Test: P<0.05)(Mann Whitney U Test: P<0.05)

Zn2+ concentrations of test and control samples of dicotyledonous plant leaves samples

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

D1 D2 D3 D4 D5 D6

Sample number

Co

nce

ntr

atio

n (

mg

/g)

Test

Control

D1C D2C D3C D4C D5C D6C

Zn

Zn2+ concentrations of test and control samples of monocotyledonous plant leaves samples

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

M1 M2 M3 M4 M5 M6

Sample number

Con

cent

ratio

n (m

g/g)

Test

Control

M1C M2C M3C M4C M5C M6C

Zn

Cd concentration was significantly high only Cd concentration was significantly high only in dicotyledonous plants (ladies fingers in dicotyledonous plants (ladies fingers plant)plant) (Mann Whitney U Test: P<0.05) (Mann Whitney U Test: P<0.05)

Cd2+ concentrations of test and control samples of dicotyledonous plant leaves samples

00.00020.00040.00060.0008

0.0010.00120.00140.00160.0018

D1 D2 D3 D4 D5 D6

Sample number

Co

nce

ntr

atio

n (

mg

/g)

Test

Control

D1C D2C D3C D4C D5C D6C

Cd

Absorption of other heavy metals did not Absorption of other heavy metals did not show a significant difference between show a significant difference between monocotyledonous and dicotyledonous monocotyledonous and dicotyledonous plants plants

There was no significant difference between There was no significant difference between concentrations of Ni and Pd in both concentrations of Ni and Pd in both dicotyledonous and monocotyledonous dicotyledonous and monocotyledonous plants of test and control samples.plants of test and control samples.

(Mann Whitney U Test: P>0.05)(Mann Whitney U Test: P>0.05)

ConclusionsConclusions

Plants grown in the dry battery dumping site have Plants grown in the dry battery dumping site have absorbed higher concentrations of some heavy absorbed higher concentrations of some heavy metals - Zn, Mn and Cd.metals - Zn, Mn and Cd.

Dicotyledonous plants (Dicotyledonous plants (Abelmoschus esculentusAbelmoschus esculentus) ) absorb more Cd than the monocotyledonous plants absorb more Cd than the monocotyledonous plants ((Buchole dactyloidesBuchole dactyloides). ).

Thank YouThank You