137
16.08 ± 1.16 ppm dry wt. (at Kakdwip) during monsoon in stem and 2.61 ± 0.09 ppm
dry wt. (at Bagmara) during premonsoon to 8.56 ± 1.21 ppm dry wt. (at Kakdwip)
in leaf respectively. During premonsoon in 2013, available Hg values in root, stem
and leaf ranged from from 0.01 ± 0.003 ppm dry wt. (at Bagmara) during premonsoon to 0.06  ±  0.004  ppm dry wt. (at Kakdwip) during monsoon in root,
0.01 ± 0.007 ppm dry wt. (at Bagmara) during premonsoon to 0.05 ± 0.009 ppm dry
wt. (at Kakdwip) during monsoon in stem and 0.01 ± 0.009 ppm dry wt. (at Bagmara)
during premonsoon to 0.04 ± 0.007 ppm dry wt. (at Kakdwip) in leaf of E. agallocha. In 2014, for the same species the values ranged from 0.02 ± 0.005 ppm dry wt.
Kakdwip
Harinbari
Chemaguri
Sagar south
Lothian island
Jambu island
Frasergunj
Gosaba
Chotomollakhali
Bali island
Sajnekhali
Bagmara
Concentration of Pb (ppm dry wt.)
Root Premonsoon
Stem Premonsoon
Leaf Premonsoon
Leaf Monsoon
Stem Postmonsoon
Leaf Postmonsoon
Stem Monsoon
Root Postmonsoon
Root Monsoon
35
25
15
5
0
10
20
30
Fig. 5.37 Spatio-temporal variations of Pb (in ppm dry wt) in the vegetative parts of Avicennia
officinalis during 2013
Kakdwip
Harinbari
Chemaguri
Sagar south
Lothian island
Jambu island
Frasergunj
Gosaba
Chotomollakhali
Bali island
Sajnekhali
Bagmara
Concentration of Cu (ppm dry wt.)
Root Premonsoon
Stem Premonsoon
Leaf Premonsoon
Leaf Monsoon
Stem Postmonsoon
Leaf Postmonsoon
Stem Monsoon
Root Postmonsoon
Root Monsoon
60
50
40
30
20
10
0
Fig. 5.36 Spatio-temporal variations of Cu (in ppm dry wt) in the vegetative parts of Avicennia
officinalis during 2014
5 Mangroves: A Sink of Heavy Metals