Metal It
Resume:
Environ Monit Assess (****) ***:*** ***
ORIGINAL ARTICLE
Monitoring of heavy metal partitioning in reef corals of
Lakshadweep Archipelago, Indian Ocean
G. Anu N. C. Kumar K. V. Jayalakshmi
S. M. Nair
Received: 7 January 2006 / Accepted: 8 May 2006 / Published online: 3 October 2006
C Springer Science + Business Media B.V. 2006
Abstract This paper focuses on the partitioning of Pb. The concentrations of trace metals in the skeleton
trace metals in ve selected coral species from and tissues of these coral species were subjected to 3
Lakshadweep Archipelago, which remains as one of way ANOVA based on non standardized original data
the least studied areas in the Indian Ocean. Based and the results showed signi cant differences between
on the morphological features, selected coral species metals and between species leading to high skeleton/
are classi ed as massive (Porites andrewsi), ramose or tissue species interaction as well as skeleton/tissue
branching (Lobophyllia corymbosa, Acropora formosa metal interaction. The signi cant values of student s t
and Psammocora contigua) and foliaceous (Montipora calculated are depicted in the form of Trellis diagrams.
digitata). Relating trace metal concentrations with mor-
phological features in skeleton, highest concentrations
Keywords Trace metals . Coral reefs .
of all the trace metals (except Zn) were reported for
Bioaccumulation . Indicator species . Archipelago .
the ramose type corals. In tissue, all the metals (essen-
Lakshadweep
tial as well as non essential) showed highest concen-
trations within the branching type corals. Irrespective
of their growth characteristics/pattern, all species ex-
cept P. contigua displayed higher concentrations of Pb, 1 Introduction
Ni, Mn and Cd within their skeleton compared to tis-
Coral reef ecosystems are widely recognized as among
sue which may exemplify a regulatory mechanism to
the most biologically diverse and complex ecosystems;
avoid the build up of the concentrations of these met-
they have been called the marine equivalent of tropi-
als in their bio-part, strikingly toxic metals like Cd and
cal rain forests. One of the greatest threats to coral
reefs is human expansion and development. Although
G. Anu
most coral reefs are widely regarded as pristine habitats
Department of Chemistry, St. Teresa s College, Cochin,
India which are not exposed to high heavy metal inputs, pol-
lution associated with contaminated river water, ef u-
N. C. Kumar . S. M. Nair ent discharges into the ocean, offshore and near-shore
Department of Chemical Oceanography, School of Marine
mining, shipping accidents and developments on the
Sciences, Cochin University of Science and Technology,
Cochin 16, India reefs themselves is known to have affected coral reefs in
e-mail: *********@*******.***
several parts of the world (Scott, 1990; Muhando et al.,
2002; David, 2003; Reichelt-Brushett and McOrist,
K. J. Jayalakshmi
2003).
National Institute of Oceanography, Cochin, India
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196 Environ Monit Assess (2007) 128:195 208
Within the reef environment, the most abundant water. The trace metal analyses were carried out on
and readily sampled organisms are corals themselves coral skeleton as well as on tissue by accepting the mod-
and they satisfy all the accepted criteria of a suitable i ed procedure of Esslemont (1999; 2000b) and it is
biomonitoring species or sentinel organism. The metal schematically represented in Figs. 2 and 3 respectively.
concentration in the skeleton phase of corals can be It was then analysed for trace metals namely Fe, Zn,
used to monitor changes in environmental metal loads Cu, Co, Cr, Cd, Mn, Pb and Ni using a graphite furnace
at polluted sites (Hanna and Muir, 1990; Druffel, 1997; atomic absorption spectrophotometer (Perkin Elmer -
Esslemont, 2000a; Hoffmann, 2002). 3110). The precision of the analysis was performed
The present work focuses on the partitioning of trace by standard spiking technique of quadruplicates and
metals (Fe, Mn, Cu, Co, Cr, Cd, Pb, Zn and Ni) in ve expressed as coef cient of variation for each element:
selected coral species from Lakshadweep Archipelago, Cu 2.8%, Co 3.1%, Cr 2.9%, Cd 2.9%, Pb 4.1%, Zn
Arabian Sea. Lakshadweep is an archipelago consist- 3.1%, Ni 2. %, Mn 2.1% and Fe 2.6%.
ing of 12 atolls, three reefs and ve submerged banks.
It is located between 8 12 13 N latitude and 71 74 2.2 Statistical analyses
E longitude and 220 440 kms away from the coastal
city of Kochi in Kerala, India (Fig. 1). Though it is a Concentrations of trace metals in skeleton and tissue of
biologically signi cant ecosystem, it remains as one of the ve coral species were subjected to 3 way ANOVA
the least studied coral reef ecosystem of the world. In for testing the signi cance of the difference in the
Lakshadweep, local life is very much dependent on the concentrations between skeleton and tissues, between
reefs and its resources. From this point of view, it be- metals and between species. The analyses also take
comes important to quantify the level of heavy metal into consideration of the signi cance of interactive ef-
pollutants on reef corals because it is likely that any ad- fects such as species speci city for metals, skeleton
verse effect on corals will ultimately affect many other or tissue speci city for metals and skeleton or tissue
reef organisms, which rely on these healthy communi- speci city for species. Based on the signi cant varia-
ties either directly or indirectly. tions obtained, student s t statistic for two sample tests
are applied, and the signi cant values are presented
in the form of Trellis diagram for species and metals
individually.
2 Materials and methods
Five coral species were collected from Lakshadweep
3 Results and discussion
Archipelago and their names and taxonomic classi ca-
tions are given in Table 1.
Concentrations of trace metals in the skeleton and tissue
parts of the coral species, Montipora digitata, Lobo-
2.1 Analyses of trace metals in corals
phyllia corymbosa, Acropora formosa, Psammocora
contigua and Porites andrewsi are depicted in Table 2
The collected samples were carefully washed with wa-
and the respective percentage wise partitions are given
ter to remove sediment and associated fauna. It was
in Table 3.
then washed with deionised water and nally in Milli-Q
Copper showed a greater af nity towards the skeletal
phase in three species, M. digitata (79%), P. andrewsi
Table 1 Names of coral species and their taxonomic classi -
(72%) and in P. contigua (63%). In L. corymbosa and
cation
in A. Formosa, the preferential enrichment of Cu was in
No Species Name Genus Family
the tissue phase. The effect of copper on scleractinian
corals is of environmental concern because there are
Lobophyllia Lobophyllia Mussidae
1
numerous sources of copper to coral reefs, and corals
corymbosa
Porites andrewsi Porites Poritidae
2 are keystone species in tropical coral reef ecosystems
Montipora digitata Montipora Fungiidae
3 (Reichelt-Brushett and Harrison, 2000; Fallon et al.,
Acropora formosa Acropora Acroporidae
4
2002). The observed comparative enrichment of Cu in
Psammocora contigua Psammocora Siderastreidae
5
the skeletal phase is only an indication of the capacity
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Environ Monit Assess (2007) 128:195 208 197
Fig. 1 Location map of Lakshadweep Archipelago
M. digitata also responded with higher concentration
of the skeleton to re ect the changes in the metal loads
of their immediate environment. of Fe in its tissue part. The tissue enrichment of Fe
Partitioning of iron in A. Formosa, L. corymbosa in all these species may be attributed to the biologi-
and in P. contigua re ected more than 80% accu- cal role of Fe in various enzymatic functions. Iron is
mulation in their tissue, whereas in P. andrewsi, Fe an essential element required by certain enzymes and
displayed a higher af nity towards the skeleton (80%). proteins that carry electron during photosynthesis and
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198 Environ Monit Assess (2007) 128:195 208
Fig. 2 Flow chart for the
analysis of trace metals in
coral skeletons
respiration (Marshall, 2002). High concentrations of Fe In all coral species examined, the lead exhibited
observed in the skeletal phase of P. andrewsi, compared a greater af nity towards the skeletal enrichment as
compared to tissue phase, except P. contigua, in which
to relatively less concentrations within its tissue, may
be pointed towards the usefulness of this species as an 96% Pb was accumulated in the tissue. Among all the
species, P andrewsi recorded the highest percentage of
indicator organism to monitor anthropogenic loads of
iron in coral ecosystems. But it has to be distinguished total Pb in its skeletal phase (98%). The enrichment of
that at polluted sites, metal concentrations in skeleton lead can take place in two ways i.e. either by adsorption
material can be used to monitor changes in environ- on the outer surface or by incorporation into the shell
matrix. Pb2+ ions can be expected to substitute some
mental metal loads, whereas in less polluted settings
of the Ca2+ ions in the 9 co-ordinate aragonite lattice
skeletal metal is probably too low and too variable to be
widely used for this purpose (Dodge and Gilbert, 1984; because lead carbonate (cerrusite) and aragonite are
Scott, 1990; Bastidas and Garcia, 1999; David, 2003). isostructural (Chester and Elder eld, 1967; Shen and
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Environ Monit Assess (2007) 128:195 208 199
Fig. 3 Flow chart for the
analysis of trace metals in
coral tissues
Boyle, 1988; Esslemont, 2000a). The enrichment of Pb A tissue wise enrichment has been recorded in the
partitioning of zinc in L. corymbosa, A. formosa and
in skeleton part may also be explained as due to transfer
P. contigua, while a slight marginal excess enrichment
of lead through tissue into skeleton suggesting discrim-
was found in the skeleton of M. digitata. Contrary to
ination by elimination (mechanism of tissue regulation
of lead concentration) combined with a natural ten- this behaviour, nearly 80% of Zn was accumulated in
the skeleton phase of P. andrewsi. Unlike the toxic
dency of lead to associate and interface with calcium
channels. Lead will bind to metallothionenin, but also chemicals that have characteristic man-made signa-
has an af nity (probably higher) for other metabolic lig- ture, trace elements like zinc have both natural and an-
ands, often associating with deposited inorganic gran- thropogenic sources. Coral tissues accumulate zinc in
ules with high concentration of calcium (Brown and tissues relative to skeleton because of its role in various
biological functions. The concentration of Zn2+ can
Holley, 1982; Elizalde et al., 2002).
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200 Environ Monit Assess (2007) 128:195 208
Table 2 Concentrations of
Heavy metal concentration ( g g 1 ) in
heavy metals ( g g 1 ) in
skeleton and tissue parts of M. digitata P. andrewsi L. corymbosa A. formosa P. contigua
Metal
coral species collected from
Lakshadweep Archipelago Skeleton
1.87 0.11 0.49 0.06 2.03 0.13 1.88 0.12 1.02 0.09
Cu
4.75 0.29 4.33 0.21 5.44 0.38 2.34 0.21 0.82 0.09
Cr
4.76 0.26 7.30 0.57 9.82 0.62 3.90 0.19 0.79 0.08
Co
5.80 0.39 11.10 0.89 12.69 0.92 10.67 0.56 2.07 0.11
Ni
13.02 0.98 24.18 1.87 26.37 1.98 23.80 1.82 0.71 0.09
Pb
1.24 0.14 2.62 0.21 2.23 0.19 2.04 0.13 1.29 0.11
Zn
2.47 0.21 2.74 0.18 3.15 0.23 4.66 0.31 0.32 0.03
Mn
1.30 0.11 2.13 0.16 2.55 0.19 2.53 0.19 0.27 0.06
Cd
11.42 0.79 5.15 0.49 12.82 0.89 0.53 0.14 2.77 0.12
Fe
Tissue
0.49 0.09 0.18 0.03 6.48 0.29 2.08 0.16 1.75 0.12
Cu
0.92 0.09 2.82 0.18 15.93 1.53 2.85 0.29 4.43 0.69
Cr
0.23 0.06 0.20 0.04 1.57 0.13 0.88 0.06 8.90 0.38
Co
0.50 0.03 0.32 0.8 10.06 0.69 3.38 0.28 9.43 0.71
Ni
0.31 0.05 0.27 0.02 12.04 0.89 4.50 0.28 20.73 1.89
Pb
0.68 0.11 0.65 0.15 9.26 0.87 2.74 0.23 2.04 0.16
Zn
0.72 0.12 0.26 0.08 1.79 0.24 0.65 0.18 2.54 0.24
Mn
0.22 0.08 0.04 0.00 1.54 0.13 0.55 0.09 2.19 0.19
Cd
16.55 1.46 1.23 0.15 62.90 4.14 19.58 1.89 11.58 1.09
Fe
Table 3 Partition of heavy metals in skeleton and tissue parts of coral species
Species Cu Cr Co Ni Pb Zn Mn Cd Fe
Skeleton
M. digitata 79.12 83.70 95.38 92.07 97.65 64.57 77.51 85.69 40.82
P. andrewsi 72.64 60.49 97.36 97.19 98.90 80.24 91.42 98.06 80.78
L. corymbosa 23.81 25.47 86.19 55.78 68.66 19.38 63.79 62.32 16.93
A. formosa 47.50 45.10 81.67 75.97 84.10 42.72 87.76 82.13 2.65
P. contigua 36.88 15.60 8.12 18.01 3.33 38.71 11.16 11.16 19.33
Tissue
M. digitata 20.88 16.30 4.62 7.93 2.35 35.43 22.49 14.31 59.18
P. andrewsi 27.36 39.51 2.64 2.81 1.10 19.76 8.58 1.94 19.22
L. corymbosa 76.19 74.53 13.81 44.22 31.34 80.62 36.21 37.68 83.07
A. formosa 52.50 54.90 18.33 24.03 15.90 57.28 12.24 17.87 97.35
P. contigua 63.12 84.40 91.88 81.99 96.67 61.29 88.84 88.84 80.67
regulate many metabolic processes through initia- Mn concentration was found to be higher in the
skeletal parts, except that in P. contigua. Since Mn2+
tion and/or regulation of the activity of the metallo-
ion is having ionic radii less than that of Ca2+, it pref-
enzymes. Essential trace elements like Cu, Zn etc that
are commonly used in protein synthesis and repair erentially accumulates in the calcite lattice of coral
(Beyersmann, 1994) would be transported to portions skeleton. Most metals are probably transferred to skele-
experiencing high growth. The poor t for many metals tal material from the tissue rather than incorporated
in the aragonite crystals and adequate bonding between into the skeletal mass directly from surrounding water
metals and organic materials act to limit metal transfer (McConchie and Harriott, 1992; Reichelt-Brushett and
from living tissue to skeletal material there by leading McOrist, 2003). Mn is an essential micronutrient, being
enhanced tissue metal concentrations (McConchie and involved in many cellular reactions which involve oxy-
Harriott, 1992). gen (such as photosynthesis) and as an activator of
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Environ Monit Assess (2007) 128:195 208 201
several enzymes, and hence the tissue enrichment of Among the selected species, the highest skeletal
the metal in P. contigua is not surprised. In all others, as well as tissue concentration of nickel was found
in Lobophyllia corymbosa (12.69 mg kg 1 and 10.06
lattice substitution may be the reason for skeletal en-
mg kg 1 respectively). Regarding the partitioning of
richment of Mn. The incorporation of manganese into
the lattice structure could take place by two routes. Ni between skeletal and tissue phases, except that in
P. contigua, all other species displayed greater af nity
One is the usual substitution in the calcite, which is
quite possible in view of the identical crystal structure of Ni towards the skeletal phase.
of calcite and rhodochrosite (manganese carbonate). Based on the above observations, the following gen-
The second pathway of manganese incorporation is by eralizations can be made to describe the metal enrich-
a geologically improbable inclusion of Mn2+ into the ment pattern of the coral species selected in this study.
aragonite lattice by biomineralization occurring during For all the species and for all metals, partition coef -
shell formation (Rosenberg, 1980). cient (KD ) is calculated as the ratio of the metal con-
Similar to the behaviour of other metals, Cd also centration in tissue to that in skeleton.
showed much af nity towards the skeletal phases
(1). Essential trace elements like Cu, Cr and Zn ex-
of M. digitata and P. andrewsi. L. corymbosa and
hibited a similar pattern of enrichment. Partition
A. formosa also displayed a similar trend. In P. con-
coef cients of these metals were less than one in
tigua, nearly 88% of the metal enrichment was found
two species (M digitata and P. andrewsi), which in-
within the tissue. The behaviour of the four coral
dicates comparatively higher af nity of these met-
species M. digitata, L. corymbosa, A. formosa and
als towards skeleton. In L. corymbosa, A. Formosa
P. andrewsa - points towards the fact that skeletons are
and in P. contigua, these metals displayed higher
recommended over tissues for monitoring purposes be-
concentrations in tissue (KD > 1).
cause they represent environmental metal loads more
(2). Though Co and Mn can be considered as es-
faithfully. Tissue metal concentrations appear to be reg-
sential trace metals, their distribution pattern
ulated possibly by preferential transport of metals into
observed in this study was identical with the
skeletons, or by elimination of metals from tissues.
so-called non essential or toxic elements
High accumulation of cadmium in the skeleton might
like Ni, Pb and Cd. For all these metals,
have resulted by the substitution of Ca2+ by Cd2+ ions
KD were less than one in four species viz.
in view of their comparable ionic radii (Shen and Boyle,
M. digitata, P. andrewsi, L. corymbosa and A.
1988).
Formosa.
Concentration of chromium in tissues and skeleton
(3). The distributional pattern of Fe was entirely differ-
parts of different species varied substantially which
ent from that of other metals. In Porites andrewsi,
may be due to growth factors, irregular distribution
the skeletal phase showed higher Fe concentra-
of particles or metal-bearing phases in coral colonies.
tion compared to tissue (KD
M. digitata showed highest metal concentrations in
species, KD values were greater than one, which
its skeleton (83%) compared to tissue, whereas in
attest the role of tissue in the accumulation of Fe
L. corymbosa, A. formosa and P. contigua, Cr showed
compared to skeleton.
greater af nity towards the tissue phase. P. andrewsi
showed a similar pattern of chromium enrichment (60%
3.1 Relating metal concentration to morphology
in skeleton) as that of M. digitata.
Cobalt shows an af nity towards the skeleton ex-
The classi cation scheme of St. John (1974) is used
cept that in P. contigua. L. corymbosa recorded a high-
here to describe various forms of corals selected for
est skeletal concentration of cobalt (9.82 mg kg 1 ),
this study.
whereas P. contigua recorded a highest tissue con-
centration (8.89 mg kg 1 ). The increased enrichment (1). Massive corals: - They form more or less thick
masses or heads. In this study, P. andrewsi, be-
in the skeleton, therefore leads to the conclusion
that biological transport of excess amount of cobalt longing to family Poritidae comes under this
into the shell structure is an active process prevail- classi cation.
ing in the body (Rasmussen et al., 1992; Esselemont, (2). Ramose corals: - They are branching type corals.
P. contigua belonging to family Siderastreidae,
2000a).
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202 Environ Monit Assess (2007) 128:195 208
L. corymbosa belonging to family Mussidae and (massive form). The lowest observed tissue concen-
tration of Cr (0.92 0.09 mg/kg) was in M. digitata
A. Formosa of family Acroporidae comes in this
category. (foliaceous form).
Though P. contigua was a ramose type coral, its
(3). Foliaceous corals; - They form thin overlapping
sheets with a small basal attachment. M. digitata metal partitioning pattern was entirely different from
the other two (L. corymbosa and A. formosa). In
of family Faviidae belongs to this classi cation.
P.contigua, partition coef cient KD (KD = [M]T/ [M]S,
Relating trace metal concentrations with morpho- where [M]T is the metal concentration in tissue and
logical features, in skeleton, highest concentrations of [M]S is the metal concentration in skeleton) for
all the trace metals except that for Zn were reported for all the metals was greater than one which is an in-
the Ramose (branching) type corals i.e. for L. corym- dication of preferential enrichment of all the metals
bosa which recorded highest concentrations of Cu, Cr, in its tissue. Metal concentrations were higher in the
Co, Ni, Pb, Cd and Fe. A. formosa, which belongs to tissues than in the skeleton, which supports the idea
the same class, recorded highest Mn concentration. The that corals discriminate against metals in their bio-
only anomaly was in the case of zinc, which displayed genic precipitation of the aragonite skeleton (St. John,
higher concentration in the massive form (P. andrewsi). 1974). The trend was exactly reversed in the massive
form (P. andrewsi) where KD values for all the met-
In tissue, all the metals (essential as well as non es-
als were less than one. In the massive form (P. an-
sential) showed highest concentrations in the branching
drewsi), all the metals displayed comparatively higher
type corals, where Cu, Cr, Ni, Zn and Fe recorded the
maximum concentrations in L. corymbosa. For metals af nity towards their skeleton. In the massive coral
like Co, Pb, Mn and Cd the observed concentrations forms a signi cant percentage of the combined in-
were high in the tissue phases of P.contigua, which ternal and external total surface area is exposed to
also belonged to ramose form. Concentrations of Fe seawater and not covered by living materials, than is
and Mn observed in the tissue phase of M.digitata (fo- the case in ramose and foliaceous forms. The massive
liaceous type) were comparable to that of the branch- forms typically manifest a larger ratio of dead sur-
ing type. Growth rate studies indicate that branching face to living coenosarcs per unit mass of carbonate
corals are more affected by local discharges, certainly than ramose or foliaceous forms (St. John, 1974). So
in terms of linear extension, whereas massive corals a number of mechanisms exist which would tend to
do not re ect such effects in their growth (Brown and augment trace metal abundances in the skeletal car-
Howard, 1985). The metal enrichment within the skele- bonate of these forms the most important one being
ton of these species was not at all related to their growth co-precipitation of heavy metals in thermodynamic
form. In skeleton, for metals like Co and Cr the species equilibrium with the seawater. This pattern was also
wise metal accumulation pattern was in the order, L. seen in the foliaceous form (M. digitata) except in
corymbosa> P. andrewsi > M. digitata > A. formosa> the behaviour of Fe. Another characteristic observation
P. contigua. Toxic elements like Ni and Pb also dis- made in this study is that irrespective of their growth
played a similar order for species wise metal accu- characteristics/patterns, four coral species namely,
mulation, which was in the order L. corymbosa> P. M. digitata, P. andrewsi, L. corymbosa and A. Formosa,
andrewsi> A. formosa> M. digitata> P. contigua. For displayed higher concentrations of Pb, Ni, Mn and Cd
all these four metals (Co, Cr, Ni and Pb) branching within their skeleton compared to tissue. This shows
type displayed highest (L. corymbosa) as well as lowest that these metals are concentrated proportionally less
(P. contigua) concentrations. Essential trace elements in tissues relative to skeleton, which is an indication of
like Cu, Zn, Mn and Fe and the toxic non-essential tissue regulation of concentration of these toxic metals.
metal like Cd exhibited variations among species (also Metals measured in coral tissues are those organically
in species with similar growth characteristics) regard- bound in the polyp, mucus and zooxanthellae. This also
ing the metal accumulation characteristics within their includes particles adhering to the mucus. Metals in the
skeleton. In tissue, the ramose type recorded much skeleton are those metabolised and precipitated in sub-
higher concentrations than the massive and foliaceous stitutional solid solution with calcium.
type corals. The lowest recorded tissue concentrations Interspecies variations in trace metal distributional
of all the metals except that for Cr was in P. andrewsi characteristics can be due to (1) variations in metal
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Environ Monit Assess (2007) 128:195 208 203
transfer ef ciencies from tissue to skeleton by different Spence, 1995; Langston and Bebianno, 1998; David,
species (2) variations in metal tolerance levels among 2003). The skeletal enrichment characteristics of four
species, (3) due to variations in the amount of zoox- metals (Pb, Ni, Mn and Cd) in this study are mainly
due to the lattice substitution of Ca2+ ions in the calcite/
anthellae associated with corals at the time of sam-
aragonite lattice of coral skeletons by Pb2+, Ni2+, Mn2+
pling because zooxanthellae are able to assimilate cer-
and Cd2+ ions by biomineralization occurring during
tain metals (Harland et al., 1990; Esslemont, 2000b;
Esslemont, et al., 2000) due to the in uence of differ- shell formation. All these four ions are found to be
having comparable ionic radii as that of Ca2+ ion,
ent reproductive states of corals (Reichelt-Brushett and
Harrison, 2000). Qualitative differences in the organic which easily accounts for lattice substitution. Lattice
matrix in additions to variations in food, feeding char- substitution of transition metals depends on a vari-
acteristics and colonial growth form (St. John, 1974) ety of factors including size compatibility, coordi-
may also be important in determining differences be- nation number, charge balance and chemical specia-
tion (Shen and Boyle, 1988). Among the +2 cations
tween, as well as within each group. For many organ-
isms, the key determinants that in uence metal accu- which exhibit octahedral coordination, ions with effec-
mulation are the relative amounts of metal present in the tive ionic radii undergo aragonite lattice substitution.
environment, together with their chemical form. They PbCO3 (cerrusite) is known to form an isostructural
may give rise to body concentrations in excess of four solid solution with aragonite in view of the compa-
rable ionic radii of Pb2+ (radius of Pb2+ = 1.29 A)
orders of magnitude above background in non regulat-
2+ 2+ 2+
and Ca (radius of Ca = 1.12 A). Cd also pos-
ing organisms, and clearly, detection of contamination
sess an ionic radius (1.10 A) similar to that of Ca2+ .
should be easy at grossly polluted sites (Langston and
Fig. 4 Trellis diagram for
signi cance of students t
statistic for comparing
between skeleton or/and
tissue for concentration of
metals in coral species from
Lakshadweep
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204 Environ Monit Assess (2007) 128:195 208
Precipitation of smaller cations like Mn2+ (ionic radius skeleton and tissue accumulation of trace metals.
0.96 A) and Zn2+ (ionic radius 0.90 A) is understood
The analyses showed signi cant differences be-
tween metals (F(8,32) = 5.8722, p 2.121) except A. formosa (p > 0.05). In tis- 2.46), L. corymbosa (t = 2.95) and A. formosa (t =
sue, high difference in the metal accumulation pattern 2.09) (Fig. 4).
was observed between P. contigua and P. andrewsi Inter-comparing the metal concentrations in the
(t = 3.00). In P. contigua, partition coef cient, KD skeleton and tissue of different coral species, it is ob-
was greater than one for all the metals, which shows served that in skeleton, distributional characteristics of
Table 4 3 way ANOVA
Source Mean sum of squares Degree of freedom F ratio Remarks
(based on original data) for
testing the signi cance of
P > 0.10
Skeleton & tissue (A) 0.076 1.32 0.0019
the differences within type
P 0.10
Interaction BC 86.004 32.32 0.9325
the interaction effects, AB,
P 0.10
Species (B) 0.003906 4.32
P > 0.10
Trace metals (C) 0.003906 8.32
P 0.10
Interaction BC 0.008167 32.32
P 0.05). Metal partitioning in the skeletal phase of all
showed a different pattern of enrichment from that of
chromium and cobalt (t > 2.43). Metals like copper, the species are highly different (2.55 0.05) and that
ilar pattern of enrichment and are accumulated in not
in the skeleton of M. digitata, P. andrewsi and A.
much different concentrations. In tissues, the concen-
formosa and also in the tissue phase of P. contigua
tration of iron is found to be signi cantly different from
that of copper (t = 1.89), cobalt (t = 1.86), manganese (p > 0.05) (Fig. 6). On comparing the partitioned values
(t = 1.99) and cadmium (t = 2.02). All other combina- between metals, it is observed that the partitioned val-
tions of concentrations are not signi cantly different ues in the skeleton and/or tissues are not signi cantly
(p > 0.10). On comparing the concentrations of metals different except that between cobalt and iron in skeleton
(t = 1.94), cobalt in skeleton and copper (t = 2.02) and
in the skeleton and tissue, signi cant differences are
nickel (t = 1.89) in tissues and iron in tissues and, iron
observed between manganese concentration in tissue
in skeleton (t = 1.86) and cobalt in tissue (t = 1.94).
and that of chromium, cobalt, nickel and lead in skele-
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metals showed signi cant differences between skele-
Porites asteroids: an evaluation of river in uence and 35
ton and tissues ((F(1,32) = 11.2878, P 0.10) as well as metal-wise (P > 0.10) Beyersmann, D. (1994). Interactions in metal carcinogenicity.
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Chester, R., & Elder eld, H. (1967). The application of infra-red
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skeleton and tissue leads to high species skeleton/tissue David, C.P. (2003). Heavy metal concentrations in growth
speci city for metals ((F(8,32) = 3.5335, p
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