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Accumulation of Trace Metals by Mangrove Plants in Indian Sundarban Wetland: Prospects for Phytoremediation

TL;DR: The findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.
Abstract: The work investigates on the potential of ten mangrove species for absorption, accumulation and partitioning of trace metal(loid)s in individual plant tissues (leaves, bark and root/pneumatophore) at two study sites of Indian Sundarban Wetland. The metal(loid) concentration in host sediments and their geochemical characteristics were also considered. Mangrove sediments showed unique potential in many- fold increase for most metal(loid)s than plant tissues due to their inherent physicochemical properties. The ranges of concentration of trace metal(loid)s for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissue were 0.006-0.31, 0.02-2.97, 0.10-4.80, 0.13-6.49, 4.46-48.30, 9.2-938.1, 0.02-0.13, 9.8-1726, 11-5.41, 0.04-7.64, 3.81-52.20 μg g (-1)respectively. The bio- concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered as a high-efficient plant for heavy metal bioaccumulation. Among all metals, Cd and Zn were highly bioaccumulated in E. agallocha (2.97 and 52.2 μg g (-1) respectively. Our findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.

Summary (4 min read)

1 Introduction

  • Imagine a homeowner trying to sell her house to a prospective buyer.
  • The authors depart from sequential screening by making the following assumptions.
  • In particular, they show that under the same conditions as in the sequential screening model of Courty and Li (2000), the seller gives up no information rent for the additional private information—all the information rent arises from the ex ante private information that the buyer has at the time of contracting.
  • The reason that discriminatory disclosure can be profitable is that an appropriate two-way partitioning, together with a selling mechanism, can achieve the same surplus with the dominated type as under the perfect signal structure, while reducing the information rent of the dominant type.

2.1 Basic Setup

  • Consider the following two-period sequential screening model.
  • For simplicity, the authors assume that all information of the buyer about ω besides his ex ante type θ is under the seller’s control.
  • Given the consistency requirement that each G (·|θ, σ) is generated from the same prior distribution F (ω, θ), this can be achieved by requiring the corresponding conditional distributions functions {G (·|θ, σ)} to satisfy “convex order,” defined as follows: Definition 1 (Convex Order).
  • For most of their results, the authors assume only that for all θ the signal structure corresponding to the distribution F (·|θ) of the true value when the seller fully discloses all the additional private information dominates any other σ in S.
  • The literature has proposed several ways to quantity how informative signal structures are: (i) Blackwell (1951) sufficiency, (ii) Lehmann (1988) and Perciso (2000) accuracy, and (iii) Athey and Levin’s (2001) monotone information order with supermodular preferences.

2.2 Full Disclosure and Partial Disclosure

  • The above framework incorporates the model of sequential screening of Courty and Li (2000) as a special case where the set of feasible signal structures is a singleton.
  • This way of modeling full disclosure gives rise to what Eso and Szentes (2007) refer to as the “orthogonal” decomposition of all the private information about ω into θ, which the buyer always knows, and s~σ, which is independent of θ. 7.
  • In orthogonal disclosure, since the distribution of sσ is independent of θ, the ordering of {F (·|θ)} by first-order stochastic dominance with respect to θ is passed on without change to the family of distributions {G(·|θ, σ)} with respect to θ for any σ.
  • This is special because the signal realization depends on the true ex ante type θ only through the true value.
  • Orthogonal disclosure is a special model in the framework the authors have set up here, and is no more natural than general disclosure policies that they study in an environment where the seller does not know the true type of the buyer when she releases additional private information.

3 Discrete Types

  • The authors start with a discrete setting where the ex ante types is binary, θ ∈ Θ ≡ {H,L} , with probability fH and fL respectively.
  • For convenience, the authors slightly adapt the notation to the binary setting.
  • Suppose that under any signal structure σ, conditional on the ex ante type θ, the posterior estimate v of the true value ω is distributed according to Gθ(·|σ) over fixed, common support [ω, ω].
  • Assume that Gθ(·|σ) has positive, continuous density gθ(·|σ) under the perfect signal structure σ = σ, and GH(·|σ) first-order stochastic dominates GL(·|σ).
  • The unconditional mean values of the two types satisfy µH > µL.

3.1 A General Characterization

  • An option contract (a, p) consists of a non-refundable advance payment a in period one for option of buying at price p in period two after the buyer forms posterior estimate v.
  • If the authors impose the restriction on S that GH(v|σ) first-order stochastic dominates GL(v|σ) for any σ ∈ S, then they can strengthen Proposition 1 in two ways.

3.2 Direct Disclosure

  • In Section 2, the authors have defined direct disclosure as a mapping σ : Θ×Ω → ∆S from reported ex ante type θ̃ and true value ω to a distribution over the signal space S. Monotone partition signal structures include the perfect signal structure as a special case.
  • The advance payments âL and âH are chosen so that both (IRL) and (ICH) bind.
  • This is why the authors need to exclude the possibility of full surplus extraction from the characterization in Proposition 1. with ε < 12 .
  • Consider the following disclosure policy: if the buyer reports type H, the seller chooses σ which reveals the true value ω; if the buyer reports type L, the seller chooses σ[c] which only reveals to the buyer whether the true value ω is above or below c = 12 .

In contrast, if the seller discloses all information to both types of buyers, the problem reduces

  • To sequential screening of Courty and Li (2000).
  • The resulting allocation involves distortion and the type-H buyer enjoys strictly positive information rent.
  • When condition (2) fails,14 the authors can apply Proposition 1 to characterize the optimal monotone partition signal structure σ[kL] for type L. Proposition 3 Suppose condition (2) fails.

3.3 Optimal Disclosure

  • Note that condition (3) ensures that type H would not buy at the price of µ+L(c) when he learns nothing, which is weaker than condition (2) for full surplus extraction with direct disclosure.
  • Then, for any signal structure σL for type L and its corresponding selling mechanism, there exists a binary signal structure for type L that reveals no information to deviating type H and is at least as profitable to the seller.
  • Corollary 1 Suppose that condition (3) fails.

L that can be generated from partitioning continuous distributions of posterior estimates, the

  • Optimal one is a generalized monotone two-way partition signal structure.
  • Proposition 5 Suppose that condition (3) fails.
  • The intuition behind Proposition 5 is clear from Corollary 1, which already suggests that the optimal signal structure for type L takes the form of a generalized monotone partition signal structure, because the latter maximizes the seller’s profit when the partition threshold is optimally chosen.

4 Continuous Types

  • Given a signal structure σ ∈ S, each type θ is represented by a distribution G (v|θ, σ) of posterior estimate v.
  • For the first two subsections, the authors restrict their attention to “continuous disclosure” where each distribution G (·|θ, σ) has a finite and positive density g (·|θ, σ).

4.1 A General Characterization

  • By the revelation principle, the authors focus on direct revelation mechanisms {{x (θ, v) , y (θ, v)}} together with disclosure policy {σ(θ)}.
  • That condition (AM), together with (FOC1), is sufficient for (IC1).
  • This validates the firstorder approach and is used in the next subsection to generate sufficient conditions for the optimality of full disclosure.

4.2 When Full Disclosure Is Optimal

  • In this subsection the authors identify information environments for which full disclosure is optimal among continuous disclosure policies.
  • These information environments share a common theme that the disclosure policy does not affect the informativeness measure.
  • The authors present two information environments studied in the literature, the first from Eso and Szentes (2007) and the second from Courty and Li (2000), in which informativeness measure I (θ, v, σ) is linear in v and independent of σ.
  • Therefore, by Proposition 7, full disclosure is optimal if the virtual surplus function J (θ, v, σ) is also monotone in both θ and v. Example 2 Suppose type θ is drawn from support [ θ, θ ] with density f (·) and distribution F (·).

As a result, the informativeness measure is

  • The aforementioned example of Eso and Szentes (2007) is a special case.
  • For their next result, the authors assume that the family of distributions {G (·|θ, σ (θ))} is rotationordered.
  • Therefore, the authors have the following proposition, and they omit its proof.
  • Graphically, the rotation order requires that two distribution functions cross each other only once.

4.3 Full Disclosure Is Not Optimal under Hazard Rate Dominance

  • So far in this section, the authors have restricted their attention to continuous disclosure policies that are associated with continuous and differentiable cumulative distributions {G (·|θ, σ (θ))} of posterior estimate v.
  • The authors will add direct disclosure back to the seller’s feasible set of disclosure policies, and show that full disclosure is then not optimal in general.
  • Let G (·|θ, σ) and g (·|θ, σ) denote its cumulative distribution and density respectively.

It is easy to see that distributions {G (ω|θ, σ)} are ordered in first-order stochastic dominance

  • As a result, the sufficient conditions for the first-order approach are satisfied (Courty and Li, 2000).
  • It can be verified that if the seller adopts the full disclosure policy, under the optimal mechanism the resulting allocation does not maximize the expected surplus, and the seller has to leave positive information rent to some high type buyers.
  • The seller discloses to all types of buyer whether ω is above or below 12 , and charges price 3 4 in period two.
  • This disclosure policy, together with the posted price, extracts all the surplus.

5 Discussion

  • In this section the authors discuss how their analysis is related to Eso and Szentes (2007).
  • First, the seller’s profit in the hypothetical setting is an upper-bound on what the seller can achieve in the original setting; and second, this upper-bound is attainable in the original setting.
  • And thus their direct approach is more general.the authors.
  • It is true that modeled as orthogonal disclosure, partial disclosure can never strictly raise the seller’s profit compared to full disclosure, which explains the claim about the optimality of full disclosure in Eso and Szentes (2007).
  • In the continuous limit, however, this hypothetical profit can be approximated, consistent with the result of Eso and Szentes (2007).

5.1 Hypothetical Setting May Not Deliver Profit Upper-bound

  • Consider first the discrete setting of Section 3.
  • As the authors have shown in Section 3 and Section 4, full disclosure is not optimal in general, regardless of whether full surplus extraction is attainable.
  • The seller’s choice is more constrained compared to the case with direct disclosure.
  • The information content of the resulting quantile, however, depends on the underlying distribution of the original type-dependent signal.

5.2 Hypothetical Profit Is Not Attainable with Discrete Types

  • The authors again take the setting with discrete ex ante types, but now assume orthogonal disclosure.
  • Then the authors consider the original setting where the seller can release, without observing, the realized quantile.
  • Denote by θi = θ + iδ the i-th type with θ0 = θ and θn = θ. Let π~σ (δ) denote the seller’s profit in the hypothetical setting, and π (δ) the maximal profit attained under the optimal menu of option contracts in the original setting.

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International Journal of Phytoremediation
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/bijp20
Accumulation of Trace Metals by Mangrove Plants
in Indian Sundarban Wetland: Prospects for
Phytoremediation
Ranju Chowdhury
a
, Paulo J.C. Favas
bc
, J. Pratas
cd
, M. P. Jonathan
e
, P. Sankar Ganesh
f
&
Santosh Kumar Sarkar
a
a
Department of Marine Science, University of Calcutta, Ballygunge Circular Road, Calcutta,
West Bengal, India
b
Department of Geology, School of Life Sciences and the Environment, University of Trás-os-
Montes e Alto Douro, UTAD, Quinta de Prados Vila Real, Portugal
c
IMAR-CMA Marine and Environmental Research Centre / MARE – Marine and Environmental
Sciences Centre, Faculty of Sciences and Technology, University of Coimbra, Coimbra,
Portugal
d
Department of Earth Sciences, Faculty of Sciences and Technology, University of Coimbra,
Coimbra, Portugal
e
Centro Interdisciplinario de Investigaciones Estudios sobre Medio, Ambiente Desarrollo
(CIIEMAD), Instituto Politécnico Nacional (IPN), Calle de Junio de Barrio la Laguna Ticomán
C.P., Del. Gustavo A. Madero, México, D.F., MEXICO
f
Department of Biological Sciences, Birla Institute of Technology and Science, Pilani,
Hyderabad Campus, Hyderabad, Telengana, India
Accepted author version posted online: 12 Jan 2015.
To cite this article: Ranju Chowdhury, Paulo J.C. Favas, J. Pratas, M. P. Jonathan, P. Sankar Ganesh & Santosh Kumar Sarkar
(2015) Accumulation of Trace Metals by Mangrove Plants in Indian Sundarban Wetland: Prospects for Phytoremediation,
International Journal of Phytoremediation, 17:9, 885-894, DOI: 10.1080/15226514.2014.981244
To link to this article: http://dx.doi.org/10.1080/15226514.2014.981244
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International Journal of Phytoremediation, 17: 885–894, 2015
Copyright
C
Taylor & Francis Group, LLC
ISSN: 1522-6514 print / 1549-7879 online
DOI: 10.1080/15226514.2014.981244
Accumulation of Trace Metals by Mangrove Plants in Indian
Sundarban Wetland: Prospects for Phytoremediation
RANJU CHOWDHURY
1
,PAULOJ.C.FAVAS
2,3
,J.PRATAS
3,4
,M.P.JONATHAN
5
, P. SANKAR GANESH
6
,
and SANTOSH KUMAR SARKAR
1
1
Department of Marine Science, University of Calcutta, Ballygunge Circular Road, Calcutta, West Bengal, India
2
Department of Geology, School of Life Sciences and the Environment, University of Tr
´
as-os-Montes e Alto Douro, UTAD, Quinta
de Prados Vila Real, Portugal
3
IMAR-CMA Marine and Environmental Research Centre / MARE Marine and Environmental Sciences Centre, Faculty of
Sciences and Technology, University of Coimbra, Coimbra, Portugal
4
Department of Earth Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
5
Centro Interdisciplinario de Investigaciones Estudios sobre Medio, Ambiente Desarrollo (CIIEMAD), Instituto Polit
´
ecnico
Nacional (IPN), Calle de Junio de Barrio la Laguna Ticom
´
an C.P., Del. Gustavo A. Madero, M
´
exico, D.F., MEXICO
6
Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Hyderabad Campus, Hyderabad, Telengana,
India
The work investigates on the potential of ten mangrove species for absorption, accumulation and partitioning of trace metal(loid)s
in individual plant tissues (leaves, bark and root/pneumatophore) at two study sites of Indian Sundarban Wetland. The metal(loid)
concentration in host sediments and their geochemical characteristics were also considered. Mangrove sediments showed unique
potential in many- fold increase for most metal(loid)s than plant tissues due to their inherent physicochemical properties. The
ranges of concentration of trace metal(loid)s for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissue were 0.006–0.31,
0.02–2.97, 0.10–4.80, 0.13–6.49, 4.46–48.30, 9.2–938.1, 0.02–0.13, 9.8–1726, 11–5.41, 0.04–7.64, 3.81–52.20 µgg
1
respectively. The
bio- concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered
as a high-efficient plant for heavy metal bioaccumulation. Among all metals, Cd and Zn were highly bioaccumulated in E. agallocha
(2.97 and 52.2 µgg
1
respectively. Our findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts,
as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.
Keywords geochemical characteristics, Excoecaria agallocha, bioaccumulation
Introduction
Mangroves are facultative halophytes and form a unique
group of intertidal ecosystems. They are increasingly
threatened due to anthropogenic chemicals sourced from
uncontrolled agricultural runoff, urban and industrial efflu-
ents and wastewaters, coupled with urbanization and pop-
ulation growth. Despite being exposed to metal contam-
inated sediments, mangroves seem to be highly tolerant
to heavy metals. This may be due to the ability of man-
groves to exclude or regulate uptake of metals at root
level and limit translocation to the shoot (MacFarlane and
Burchett 2001). Mangrove sediments are anaerobic and re-
duced, as well as rich in sulphide and organic matter. They
Address correspondence to Santosh Kumar Sarkar, Department
of Marine Science, 35 Ballygunge Circular Road, Calcutta, West
Bengal 700019, India.
Color versions of one or more of the figures in the article can
be found online at www.tandfonline.com/bijp.
therefore favor the retention of water-borne trace metals
(Tam and Wong 2000) and the subsequent oxidation of sul-
phides allows metal mobilization and bioavailability (Clark
et al. 1998).
The present study has been undertaken with the following
objectives: (i) to investigate the extent of accumulation and
the distribution of trace metal(loid)s in individual plant tis-
sues (ii) to establish correlation between metal(oids) present
in sediments and plant tissues and (iii) to find out the suitable
candidate for phytoremediation species to be used for con-
servation and sustainable management of Sundarban coastal
regions.
Materials and Methods
Area of Investigation
The Indian Sundarban, formed at the estuarine phase of the
Hugli (Ganges) River Estuary is a tide-dominated mangrove
wetland belonging to the low-lying humid and tropical coastal
Downloaded by [Universidade de Tras-os-Montes e Alto Douro] at 04:51 08 July 2015

886 R. Chowdhury et al.
zone. This vulnerable environment suffers from environmen-
tal degradation due to rapid human settlement, tourism and
port activities, and operation of excessive number of mech-
anized boats, deforestation and increasing agricultural and
aquaculture practices. A significant ecological change is pro-
nounced in this area due to reclamation of land, deforesta-
tion, huge discharges of untreated or semi-treated domestic
and municipal wastes and effluents from multifarious indus-
tries such as tanneries, chemicals, paper and pulp, phar ma-
ceuticals as well as contaminated mud disposal from harbor
dredging. All these factors impart a variable degree of anthro-
pogenic stresses leading to elevated concentrations of heavy
metals.
Two study sites, Chandanpiri (S
1
) and Jharkhali (S
2
)have
been chosen for the present investigation, covering the eastern
and western flank of Sundarban (Fig. 1). The later (S
2
) is more
diversely populated with mangrove species (n = 7) than the
former (S
1
)(n= 4) and this anomalous distribution patterns
of mangrove species is related to multiple factors, such as in-
fluence of environmental gradients (especially salinity), wave
energy and tidal amplitude controlling sediment dispersal pat-
terns.
Collection and Processing of Sediment Samples
Sediment samples were collected in triplicate from top 0–5 cm
of the surface at each sampling site (Corsolini et al. 2012)
over an area of 1m x 1m using a clean, acid-washed plastic
scoop. Samples were stored in clean plastic zip lock pouches
and transported to the laboratory. Individual sediment sam-
ples were placed in a ventilated oven at low temperature (max.
45
C) (Watts et al. 2013) as high temperature may contribute
to the alteration of volatile and even non- volatile organics of
the sample (Mudroch and Azcue 1995), until they get com-
pletely dried. Samples were pulverized using an agate mortar
and pestle, sieved through 63 µm metallic mesh since this frac-
tion contains more sorbed metal per gram of sediment due to
its larger specific surface area (Chatterjee et al. 2009) and indi-
vidually transferred into pre-cleaned, inert polypropylene bags
and stored at room temperature until subsequent extraction
and chemical analyses. Sediment pH was determined by pH
meter (Water Analyzer 371). Organic carbon (C
org
) content
of the sediments was determined following a rapid titration
method (Walkey and Black, 1934). Mechanical analyses of
substrate sediments were done by sieving in a Ro-Tap shaker
(Krumbein and Pettijohn 1938), and statistical computation
of textural parameters was done by using the formulae of
Folk and Ward (1957) and following standards of Friedman
and Sanders (1978).
Collection and Preservation of Mangrove Samples
During October November (2012), plant organs of Avicen-
nia officinalis, A. marina, A. alba (Avicenniaceae), Bruguiera
gymnorrhiza, Ceriops tagal, Rhizophora apiculata (Rhi-
zophoraceae), Aericeros corniculatum (Myrsinaceae), Ex-
coecaria agallocha (Euphorbiaceae), Lumitzera racemosa
(Combretaceae), Heritiera fomes (Malvaceae), Sonneratia
caseolaris (Lythraceae) were randomly collected, from dif-
ferent trees belonging to the same species at low tide
conditions for root / pneumatophore collection in tidal
exposure.
For analyses of plant samples, we took leaves of two differ-
ent stages of development: young and mature as well as trunk
bark, pneumatophores/roots in consideration. Sample organs
were collected from trees that were greater than 1m tall with a
girthatbreastheightofgreaterthan2cmandthatwereofsim-
ilar health conditions (as determined by degree of predation
on leaves) and were then sampled with a thin stainless steel
knife. Samples were t horoughly washed by deionised water in
the laboratory to remove dust, sediment particles and algal
trace. These were oven-dried under 50
C until they became
completely dried and then homogenized (methods adapted
by MacFarlane et al. 2003). Samples were preserved in clean
sealed plastic zip pouches for further analyses.
Analytical Protocol
The dried sediment samples were prepared by microwave di-
gestion (Multiwave 3000, Anton Paar) with aqua regia in
closed Teflon vessels (Walsh et al. 1997). The determination of
total metal(loid) contents was performed using current ana-
lytical methods, including: Atomic Absorption Spectrometry
(AAS, SOLAAR M Series equipment from Thermo–Unicam)
for Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn; coupled graphite fur-
nace AAS for As and Cd; and a hydride generation system
(HGS) linked to an atomic absorption for Hg. Most of the
trace metal(loid)s in consideration were very low in concen-
tration in the samples, so precautions were taken and necessary
instruments were used for particular trace metal(loid)s.
The plant samples were also microwave digested with an
HNO
3
–H
2
O
2
mixture in closed Teflon vessels, which was fol-
lowed by analysis with AAS for Cu, Fe, Mn and Zn; coupled
graphite furnace AAS for As, Cd, Co, Cr, Ni and Pb due to the
reduced sample amount and to increase sensitivity; and a hy-
dride generation system (HGS) linked to an atomic absorption
for Hg (Fletcher 1981; Brooks 1983; Van Loon 1985).
The detection limits for metal(loid)s in sediment samples
were 0.004 µgg
1
for Cd; 0.01 µgg
1
for As and Hg; 0.4 µg
g
1
for Zn; 1 µgg
1
for Co, Cu, Mn and Ni, 1.5 µgg
1
for Cr
and Pb; 2 µgg
1
for Fe. The detection limits for metal(loid)s
in plant samples were 0.002 µgg
1
for Cd; 0.005 µgg
1
for
As, Hg and Pb; 0.01 µgg
1
for Cr and Ni; 0.02 µgg
1
for
Co; 0.5 µgg
1
for Cu and Mn; 0.8 µgg
1
for Fe; 0.2 µgg
1
for Zn.
Quality assurance and quality control
Certified reference material for sediment (2711 SRM reference
material Montana Soil, from LGC Promochem, Barcelona,
Spain), and for plant materials (Virginia Tobacco Leaves
(CTA-VTL-2, Poland), were used to ensure the quality con-
trol and accuracy of the analyses. The agreement between the
certified reference values and the values determined by the
analytical method were in the range of 87.8% to 108.2%.
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Accumulation of Trace Metals by Mangrove Plants in Sundarban 887
Fig. 1. Map showing location of two study sites Chandanpiri (S
1
) and Jharkhali (S
2
) in Indian Sundarban wetland.
Concentration and Translocation Factors
In order to compare the degree of storage of the metal(loid)s,
bio- concentration factors (BCF) were calculated as con-
centration of metal(loid) in tissue over the concentration of
metal(loid) in sediment. Translocation factor (TF) was de-
scribed as ratio of trace metal(loid)s in plant shoot to that in
plant root (Usman and Mohamed 2009; Usman et al. 2012).
It is important to note that TF>1 indicates that the plant
translocates metals effectively from root to the shoot (Baker
and Brooks 1989).
Statistical Analyses
Partitioning of individual metal(loid)s in plant tissues and sed-
iments were pooled over site and sampling time and analyzed
using one-way ANOVA in the ANOVA module of STATIS-
TICA Statsoft Inc. 1995. Statistica for windows release 5.0.
Tulsa. Oklahoma. USA. It was assessed by using MINITAB
13. Weightage of independent variables was assessed by stan-
dardized beta coefficients (Statsoft Inc. 1995. Statistica for
windows release 5.0. Tulsa. Oklahoma. USA). Independent
variables examined with exponential accumulation relation-
ships were log transformed ln (x + 1), prior to all calculation
(Zar 1966).
Results and Discussion
Sediment Geochemistry
Sediment showed differences in their physicochemical proper-
ties pertaining to pH, C
org
and textural properties. Values of
pH are characterized by mild alkaline in nature (7.76–8.01)
and were similar between plants within the same location
(p > 0.05). According to Middleburg et al. (1996) mangrove
sediments have basic pH values due to the limited buffer ca-
pacity of these sediments. The C
org
values showed very low
concentrations (0.60–0.66%), which might be the result of
marine sedimentation and mixing processes at the sediment-
water interface where the rate of delivery as well as the rates
of degradation by microbial-mediated processes can be high
(Canuel and Martens 1993). Regarding texture, sediment sam-
ples exhibit a variable admixture of sand (1.80–15.45%), silt
(32.58–38.93%) and clay (51.98–59.28%). A variable amount
of erosion and depositions in study sites can explain the ob-
served heterogeneity in textural contents.
Possible sediment enrichment of metal(loid)s was evaluated
in terms of the geoaccumulation Index (I
geo
)ofM
¨
uller (1979).
It consists of seven classes. Class 0 (practically unpolluted): I
geo
0; Class 1 (unpolluted to moderately polluted): 0 < I
geo
< 1;
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Citations
More filters
Journal ArticleDOI
Zhifeng Huang1, Chengyou Liu, Xingru Zhao, Jing Dong, Binghui Zheng 
TL;DR: In this article, surface sediment was collected from the Zhuzhou Reach of the Xiangjiang River and eight heavy metals were investigated, and their average concentration fell in the order of Zn, Pb, and As.
Abstract: The Xiangjiang River is an important drinking water resource for the Hunan Province of China. It is crucial to ascertain the pollution status, influencing factors, ecological risks, and possible sources of heavy metals in the sediments of the Xiangjiang River. Sediment is both a source and a sink of heavy metals in aquatic ecosystems. In this study, surface sediment was collected from the Zhuzhou Reach of the Xiangjiang River and eight heavy metals were investigated. In all sediment samples, all eight heavy metals were detected and their average concentration fell in the order of Zn > Pb > As > Cu > Cr > Ni > Cd > Co. Assessment shows extremely serious Cd pollution and a very high potential ecological risk from Cd. According to correlation analysis and principal component analysis (PCA), As, Cu, Ni, Pb, and Zn originate from industrial wastewater and mineral smelting activities, whereas Co, Cr, and Ni come from natural sources. Redundancy analysis (RDA) reveals that the organic matter content and the particle size of the sediment have a certain influence on the enrichment of heavy metals. Among all eight examined heavy metals in the surveyed area, the content of Zn, Pb, and As is the highest, and that of Cd and Co is the lowest. Despite a low level of absolute content, the Cd in sediment already renders a high ecological risk and thus calls for urgent attention. Anthropogenic activities are the main source of heavy metals in the sediment. The distribution of heavy metals may also be influenced by sediment properties. The results provide guidance for controlling heavy metal pollution and protecting drinking water sources in the Xiangjiang River.

88 citations

Journal ArticleDOI
TL;DR: Samples for sediment and two species of native mangrove plants were collected from seven sampling sites for assessing the level of metal contamination and transfer factor values were found to be below 1 in both plant species, which reflects the phytoremediation ability of plants.

83 citations

Journal ArticleDOI
TL;DR: The results indicated that the Zarrin-Gol River could not be used as a reference site at least for arsenic and selenium.

70 citations

Journal ArticleDOI
TL;DR: The aim of the present study was to analyse the concentrations of seven trace elements in 14 different animal and plant species collected in the Sundarbans in Bangladesh to study their transfer through the food web and to determine whether their levels in edible species are acceptable for human consumption.

68 citations


Cites background from "Accumulation of Trace Metals by Man..."

  • ...Relationship between the concentrations of trace (Chowdhury et al., 2015), and S. leiura (0.08 mg kg−1)....

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  • ...Relationship between the concentrations of trace (Chowdhury et al., 2015), and S....

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Journal ArticleDOI
TL;DR: PCA and correlation matrix analysis indicates that Pb and Zn may have anthropogenic sources and As, Ni, Zn, Cu, Cr may come from natural sources.

65 citations

References
More filters
Journal ArticleDOI
TL;DR: WALKLEY as discussed by the authors presented an extension of the DEGTJAas discussed by the authorsF METHOD for determining soil organic matter, and a proposed modification of the CHROMIC ACID TITRATION METHOD.
Abstract: AN EXAMINATION OF THE DEGTJAREFF METHOD FOR DETERMINING SOIL ORGANIC MATTER, AND A PROPOSED MODIFICATION OF THE CHROMIC ACID TITRATION METHOD A. WALKLEY;I. BLACK; Soil Science

17,132 citations

Journal ArticleDOI
TL;DR: In this paper, a bar on the Brazos River near Calvert, Texas, has been analyzed in order to determine the geologic meaning of certain grain size parameters and to study the behavior of the size fractions with transport.
Abstract: A bar on the Brazos River near Calvert, Texas, has been analyzed in order to determine the geologic meaning of certain grain size parameters and to study the behavior of the size fractions with transport. The bar consists of a strongly bimodal mixture of pebble gravel and medium to fine sand; there is a lack of material in the range of 0.5 to 2 mm, because the source does not supply particles of this size. The size distributions of the two modes, which were established in the parent deposits, are nearly invariant over the bar because the present environment of deposition only affects the relative proportions of the two modes, not the grain size properties of the modes themselves. Two proportions are most common; the sediment either contains no gravel or else contains about 60% gravel. Three sediment types with characteristic bedding features occur on the bar in constant stratigraphic order, with the coarsest at the base. Statistical analysis of the data is based on a series of grain size parameters modified from those of Inman (1952) to provide a more detailed coverage of non-normal size curves. Unimodal sediments have nearly normal curves as defined by their skewness and kurtosis. Non-normal kurtosis and skewness values are held to be the identifying characteristics of bimodal sediments even where such modes are not evident in frequency curves. The relative proportions of each mode define a systematic series of changes in numerical properties; mean size, standard deviation and skewness are shown to be linked in a helical trend, which is believed to be applicable to many other sedimentary suites. The equations of the helix may be characteristic of certain environments. Kurtosis values show rhythmic pulsations along the helix and are diagnostic of two-generation sediments.

6,310 citations


"Accumulation of Trace Metals by Man..." refers methods in this paper

  • ...Mechanical analyses of substrate sediments were done by sieving in a Ro-Tap shaker (Krumbein and Pettijohn 1938), and statistical computation of textural parameters was done by using the formulae of Folk and Ward (1957) and following standards of Friedman and Sanders (1978)....

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Journal ArticleDOI
TL;DR: A table of abundances of the elements in the various major units of the Earth's lithic crust with a documentation of the sources and a discussion of the choice of units and data is presented in this article.
Abstract: This paper presents a table of abundances of the elements in the various major units of the Earth's lithic crust with a documentation of the sources and a discussion of the choice of units and data.

4,619 citations

Book
01 Apr 1990
TL;DR: In this article, the origin of heavy metals in soils is discussed, and methods of analysis for heavy metal analysis in soils are presented, as well as the potential environment significance of less abundant elements.
Abstract: General principles. Introduction. Soil processes and the behaviour of heavy metals. The origin of heavy metals in soils. Methods of analysis for heavy metals in soils. Individual elements. Arsenic. Cadmium. Chromium and nickel. Copper. Lead. Maganese and cobalt. Mercury. Selenium. Zinc. Other less abundant elements of potential environment significance. Appendices.

4,025 citations

Journal ArticleDOI
TL;DR: In this article, matching biological and chemical data were compiled from numerous modeling, laboratory, and field studies performed in marine and estuarine sediments, and two guideline values (an effects range low and an effects range median) were determined for nine trace metals, total PCBs, two pesticides, 13 polynuclear aromatic hydrocarbons (PAHs), and three classes of PAHs.
Abstract: Matching biological and chemical data were compiled from numerous modeling, laboratory, and field studies performed in marine and estuarine sediments. Using these data, two guideline values (an effects range-low and an effects range-median) were determined for nine trace metals, total PCBs, two pesticides, 13 polynuclear aromatic hydrocarbons (PAHs), and three classes of PAHs. The two values defined concentration ranges that were: (1) rarely, (2) occasionally, or (3) frequently associated with adverse effects. The values generally agreed within a factor of 3 or less with those developed with the same methods applied to other data and to those developed with other effects-based methods. The incidence of adverse effects was quantified within each of the three concentration ranges as the number of cases in which effects were observed divided by the total number of observations. The incidence of effects increased markedly with increasing concentrations of all of the individual PAHs, the three classes of PAHs, and most of the trace metals. Relatively poor relationships were observed between the incidence of effects and the concentrations of mercury, nickel, total PCB, total DDT and p,p′-DDE. Based upon this evaluation, the approach provided reliable guidelines for use in sediment quality assessments. This method is being used as a basis for developing National sediment quality guidelines for Canada and informal, sediment quality guidelines for Florida.

3,869 citations


"Accumulation of Trace Metals by Man..." refers result in this paper

  • ...Comparing our data with Effects Range Low (ERL) and Effect Range Medium (ERM) values (Long et al. 1995), majority of the trace metals (except Cu, Ni and Hg) showed lower concentrations than ERL....

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Frequently Asked Questions (13)
Q1. What contributions have the authors mentioned in the paper "Accumulation of trace metals by mangrove plants in indian sundarban wetland: prospects for phytoremediation" ?

Accumulation of Trace Metals by Mangrove Plants in Indian Sundarban Wetland: Prospects for Phytoremediation Ranju Chowdhury, Paulo J. C. Favas, J. Pratas, M. P. Jonathan, P. Sankar Ganesh & Santosh Kumar Sarkar a Department of Marine Science, University of Calcutta, Ballygunge Circular Road, Calcutta, West Bengal, India b Department of Geology, School of Life Sciences and the Environment, University of Trás-osMontes e Alto Douro, UTAD, Quinta de Prados Vila Real, Portugal c IMAR-CMA Marine and Environmental Research Centre / MARE – Marine and Environmental Sciences Centre, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal d Department of Earth Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal e Centro Interdisciplinario de Investigaciones Estudios sobre Medio, Ambiente Desarrollo ( CIIEMAD ), Instituto Politécnico Nacional ( IPN ), Calle de Junio de Barrio la Laguna Ticomán C. P., Del. Gustavo A. Madero, México, D. F., MEXICO f Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, Hyderabad Campus, Hyderabad, Telengana, India Accepted author version posted online: 12 Jan 2015. 

These include sediment-plant interactions, modifications of anatomical structure of the plant organs as well as intracellular binding mechanisms. 

Possible physiological mechanisms responsible for restricted uptake and translocation within plants include cell wall immobilization, complexation with substances such as phytochelatins and barriers at the root endodermis (Baker and Walker 1990). 

Sediment samples were collected in triplicate from top 0–5 cm of the surface at each sampling site (Corsolini et al. 2012) over an area of 1m x 1m using a clean, acid-washed plastic scoop. 

According to Middleburg et al. (1996) mangrove sediments have basic pH values due to the limited buffer capacity of these sediments. 

The determination of total metal(loid) contents was performed using current analytical methods, including: Atomic Absorption Spectrometry (AAS, SOLAAR M Series equipment from Thermo–Unicam) for Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn; coupled graphite furnace AAS for As and Cd; and a hydride generation system (HGS) linked to an atomic absorption for Hg. 

The lack of standard norms and strict regulation about fuel being used in mechanized boats for ferrying and fishing throughout the year lead to deposition of metals. 

The present result suggests the role of mangrove plants in extracting heavy metals from contaminated sites might be dependent on sediment metal availability. 

These mechanisms include the sub-cellular compartmentalization of the metal, namely in vacuoles, and the sequestration of the metal by specially produced organic compounds, like phytochelatins, concentrating metal in the plants roots (Ross and Kaye 1994). 

Thus these two organs act as a barrier for metal translocation and protect the sensitive aerial parts of the plants from metal contamination (Pahalawattaarachchi et al. 2009). 

Suggested mechanisms for reduced bioavailability of metals in sediments are precipitation as sulphides under anaerobic conditions, organicD ownl oade dby [U nive rsid ade deT rasos-M onte se Alto Dou ro] at0 4:51 08 July 201 5Accumulation of Trace Metals by Mangrove Plants in Sundarban 889Fig. 

The bio- concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered as a high-efficient plant for heavy metal bioaccumulation. 

Regarding texture, sediment samples exhibit a variable admixture of sand (1.80–15.45%), silt (32.58–38.93%) and clay (51.98–59.28%).