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Role of Plant Biomass in the Global Environmental Partitioning of Chlorinated Hydrocarbons

Authors:

Abstract

Plant biomass plays a significant role in the global environmental partitioning phenomena and plants are good indicators of tropospheric contamination levels by chlorinated hydrocarbons. In the present research 300 samples of plants were collected in 265 areas distributed worldwide and analyzed for HCB (hexachlorobenzene), α-HCH (hexachlorocyclohexane), γ-HCH, p,pâ²-DDT,o,pâ²-DDT, and p,pâ²-DDE (degradation product of DDT). Global HCB distribution is strongly dependent on the temperature, the HCB being present mainly in samples from cold areas. The sum of DDTs show higher concentrations in samples from topical areas, while the sum of HCHs is higher in the plants from the Northern Hemisphere. These results are discussed, taking into account the role of physicochemical properties in determining the global distribution as well as the air age of the contamination.
Environ. Sci. Technol.
PCDD/F formation on fly ashes, the effect
of
inhibitors
was studied by this technique. While no inhibitory action
was observed for triethylamine, ethanolamine was shown
to act as a very efficient inhibitor, by blocking the active
sites of copper surfaces.
At
this point it is important to
draw attention to the differences between the carefully
prepared surfaces investigated in this study, and the highly
heterogeneous fly ash in the complex environment of an
incinerator. Details of the phenomena observed in the
laboratory cannot be transferred
to
the technical plant, and
we cannot exclude the possiblity that other modes of in-
hibitory action are important in the incinerator environ-
ment. However, the relevant results on the inhibition of
dioxin formation obtained in the pilot plant are consistent
with the mechanisms proposed in this study.
Acknowledgments
We thank
0.
Hutzinger for his support, and M. McLa-
chlan for reading the manuscript.
Registry
No.
Cu, 7440-50-8; PhOH, 108-95-2; Phz, 92-52-4;
BrPh, 108-86-1; sodium phenolate, 139-02-6; ethanolamine, 141-
43-5.
Literature
Cited
Altwicker, E. R.; Schonberg,
J.
S.;
Konduri, R. K. N. V.;
Milligan,
M.
S.
Chemosphere
1990,
20,
1935.
Shaub, W. M.; Tsang, W.
Environ. Sci. Technol.
1983,17,
721.
Karasek,
F.
W.; Dickson, L. C.
Science
1987, 237, 754.
Vogg, H.; Stieglitz L.
Chemosphere
1986,
15,
1373.
Hagenmaier, H. P.; Kraft, M.; Brunner, H.; Haag, R.
En-
uiron. Sci. Technol.
1987, 21, 1080.
Gullett, B. K.; Bruce, K. R.; Beach, L.
0.
Chemosphere
1990,
21, 1945.
1991,25,
1489-1495
(7) Hoffmann, R. V.; Eicemann,
G.
A.; Long, Y.-T.; Collins, M.
C.;
Lu, M.-Q.
Environ. Sci. Technol.
1990,
24,
1635.
(8)
Zier, B.; Lenoir, D.; Lahaniatis, E.; Kettrup,
A.
Chemo-
sphere,
in press.
(9) Dickson, L.
C.;
Lenoir, D.; Hutzinger,
0.;
Naikwadi, K. P.;
Karasek,
F.
W.
Chemosphere
1989, 19, 1435.
(10)
Lenoir, L.; Dickson, L.
C.;
Hutzinger,
0.
chemosphere,
in
press.
(11)
Lenoir, D.; Hutzinger,
0.;
Mutzenich,
E.;
Horch, K.
Z.
UWSF Umweltchem. Okotox.
1990,
1,
3.
(12)
Karasek, F.; Naikwadi, K.
P.
Proceedings of “Dioxin
90”;
Ecoinforma: Bayreuth, Germany, 1990; Vol. 3, p
127.
(13) Fanta,
P.
E.
Synthesis
1974,
1,
9.
(14) Koshelev, V.
J.
Ser. Khim. Nauk.
1983,
No.
4, 86.
(15) Moroz, A. A.; Shvartsberg, M.
S.
Russ. Chem. Rev. (Engl.
(16) Dickson, L.
C.
Thesis, Waterloo, 1987; p
112.
(17) Lippert, T.; Lenoir, D.; Wokaun, A.
Ber. Bunsenges. Phys.
(18)
Kagel, R.
0.
J.
Catal.
1970, 16, 316.
(19) Jobson, J.; Baiker, A.; Wokaun, A.
Ber. Bunsenges. Phys.
(20) Jobson,
E.;
Baiker, A.; Wokaun, A.
J.
Chem. SOC., Faraday
Transl.)
1974,
43,
1443.
Chem.
1990,94, 1465.
Chem.
1989,93, 64.
Trans.
1990,86, 1131.
(21)
Kritzenberger, J.; Jobson, J.; Wokaun, A.; Baiker, A.
Catal.
Lett.
1990,
5,
73.
(22)
Hecker, W. C.; Bell, A.
T.
J.
Catal.
1981, 71, 216.
(23) Baiker, A.; Richarz,
W.
Synth. Commun.
1987,
8,
27.
(24) Morello, T.; Eng,
P.
Proceedings, Meeting on Dioxin In-
hibition in MWI Plants, Augsburg, April 2, 1990.
(25) Sokoll, R.; Hobert, H.; Schmuck,
J.
J.
Catal.
1990,121,153.
(26) Baiker, A.; Kijenski,
J.
Catal. Reu. Sci. Eng.
1985,27,653.
(27) Baiker, A.; Monti,
D.;
Son Fan,
Y.
J.
Catal.
1984,88,81.
Received for review December
1,
1990.
Revised manuscript
received April
29,1991.
Accepted May
3,1991.
This work has
been supported by grants of the Deutsche Forschungsgemeins-
chaft
(SFB
213).
Role
of
Plant Biomass in the Global Environmental Partitioning
of
Chlorinated
Hydrocarbons
Davide Calamari,
*It
Eros Baccl,* Sllvano Focard1,Z Carlo Gaggi,* Marco Morosini,t and Marco Vighlt
Institute
of
Agricultural Entomology, University of Milan, via Ceioria
2,
20133
Milan, Italy, and Department
of
Environmental
Biology, University
of
Slena, via delle Cerchia
3,
53100 Siena, Italy
Plant biomass plays a significant role in the global
environmental partitioning phenomena and plants are
good indicators of tropospheric contamination levels by
chlorinated hydrocarbons. In the present research
300
samples of plants were collected in
26
areas distributed
worldwide and analyzed for HCB, a-HCH, yHCH,
p,p’-
DDT, o,p’-DDT, and p,p’-DDE. Global HCB distribution
is strongly dependent on the temperature, the HCB being
present mainly in samples from cold areas. The sum of
DDTs show higher concentrations in samples from tropical
areas, while the sum of HCHs is higher in the plants from
the Northern Hemisphere. These results are discussed,
taking into account the role of physicochemical properties
in determining the global distribution as well as the air
concentrations, the use patterns of the chemicals, and the
age of the contamination.
Introduction
In recent years there has been increasing interest in
global Contamination from persistent organic chemical
University
of
Milan.
t
University
of
Siena.
substances, such as chlorinated hydrocarbons. Concen-
trations
in
air
have been measured and attempts have been
made to evaluate the role of the atmosphere in world
transport and contamination of remote areas
(1-3).
Some groups have attempted to reconstruct the cycling
mechanisms of these molecules
(4),
others to quantify the
atmospheric inputs to the worlds oceans
(5)
and
to
compile
a global mass balance
(6).
Remote and especially cold areas have been the subject
of particular attention and analyses of atmospheric chlo-
rinated pesticides have been performed in Antarctica,
Sweden, and Arctic Canada
(2,
7,
8).
In terrestrial ecosystems, plant biomass is believed to
play a significant role in the circulation and bioaccumu-
lation phenomena of these chemicals, and the air to leaf
transfer
of
gaseous organics can be considered a key pro-
cess, particularly for less soluble compounds
(9-14).
To contribute to a better understanding of both issues,
this research group has measured chlorinated hydro-
carbons in foliage as an indication of tropospheric con-
tamination levels
(1.9,
their contents in lichen and moss
samples from the Antarctic Peninsula as base-line levels
of world contamination
(16),
and organochlorine residues
in mango foliage from West Africa
(17).
This paper is an
0013-936X/91/0925-1489$02.50/0
0
1991
American Chemical Society Environ.
Sci.
Technol.,
Vol.
25,
No.
8, 1991
1489
Flgure
1.
Geographical distribution
of
the
26
sample sites.
Table
I.
Information
on
the
26
Sample
Sites
site
1.
Spitsbergen
2.
Iceland
3.
Scandinavia
4.
Foroyar
5.
Italy
6.
New Delhi
7.
Nepal
8.
Nepal Mountains
9.
Everest
10.
Guatemala
11.
Mali-Guinea
12.
Delta Amacuro
13.
Benin Burkina Faso
14.
Ghana Suhum
15.
Ivory Coast
16.
Ghana Accra
17.
Amazonas
18.
Mount Kenya
19.
Kenya Nairobi
20.
Kenya Mombasa
21.
Bolivia
22.
Capetown
23.
Tristan da Cunha
24.
Tierra del Fuego
25.
Antarctic Peninsula
26.
Kay Island
lat.
78'
N
65'
N
70-60"
N
62'
N
29'
N
46-41'
N
29-27'
N
29-27'
N
16-14'
N
12-9'
N
11-8'
N
12-6'
N
28'
N
a"
N
7'
N
6'
N
5-4'
N
0"
1'
s
4'
s
18'
S
33'
s
38's
54'
s
65-68"s
74'
s
long.
15'
E
20'
w
18-33'
E
7'
w
9-16'
W
77'
E
84-87'
84-87'
E
89-91'
W
8-10'
W
87'
E
60-63'
2'
E
1'
E
5'
E
1'
E
37'
E
37'
E
39'
E
68'
W
18'
E
12'
w
68'
W
65'
W
165'
E
67-68'
W
altitude,
m
0
100-500
500-700
100-500
100-300
250
800-2500
2500-4700
5600
600-2500
200-500
0
0-300
100-200
200-500
0
200-500
3100-4900
1700
0
3800-5300
0
0
0
0
0
no.
of
samples
20
8
18
9
2
8
21
32
6
4
12
7
7
20
5
32
16
23
2
5
9
1
10
6
12
11
plant species
lichens, mosses
lichens, mosses
lichens, mosses
lichens, mosses
lichens
mango
lichens, mosses
lichens, mosses
lichens, mosses
mango, lichens
mango
lichens, mosses
mango
mango
mango
mango
lichens, mosses
lichens, mosses
mango
mango
lichens, mosses
mango
lichens, mosses
lichens, mosses
lichens, mosses
lichens, mosses
extention
of
a previous investigation, analyzing more
samples from different areas of the world with the aim
of
contributing to the understanding and quantification of
the global cycling of these xenobiotics.
Materials and Methods
Selection
of
Foliage Samples.
In cold and temperate
areas and at high altitudes (above 2500 m), lichen and moss
samples were collected. In tropical areas, fallen mango
leaves
(Mangifera indica)
were chosen due to their wide
distribution.
All the samples were wrapped in aluminum foil, kept
cold (-5
"C)
whenever possible, and then stored at -20
OC until pretreatment.
Sample Collection.
A
total of
300
samples (-10
g
each) were collected in
26
areas of the world.
A
detailed description of the type of sampling would be
lengthy and unnecessary but as a general rule in each area
a variable number of samples were collected along transects
of
tens to hundreds
of
kilometers
of
length, which were
considered as representative
of
the entire geographic area.
The sample collectors were, in a few cases, volunteers,
but most of the work was done by the authors
of
this paper
within 1985-1988. Two sampling programs in West Africa
and in Antarctica were considered necessary
for
inter-
preting the results.
Only a few samples were obtained from Iceland, Cape-
town, Nairobi, Kenya, and Italy and these were pooled due
to the low weight
of
the biomass but were included in the
paper as representative of the areas. Figure
1
shows the
sample sites on a world map while Table
I
gives geographic
areas, numbers of samples, types
of
plants collected, ap-
proximate altitudes above sea level, latitude, and longitude.
Chemical Analysis.
After partial oven-drying, minced
samples were extracted in a Soxhlet apparatus with
n-
hexane
as
solvent. Residual water content was measured
1400
Environ.
Sci. Technol.,
Vol.
25,
No.
8,
1991
Table
11.
Selected Physicochemical Properties
of
the
Molecules Studied
8-
6~
7-
1:
3-
2-
VP
P,,"
MW
Pa
HCB 284.8 1.5
X
a-HCH
290.9 3.0
X
y-HCH 290.9 4.0
X
p,p'-DDT
354.5 2.5
X
O,~'-DDT
354.5 4.5
x
10-4
p,p'-DDE
318.0
8.0
X
"At
20
OC.
c50
s
UC8
HCB
HCH.
aOT.
__~__
0.12
4.3
26///::
6.7
.A
0.01
0.1
1
10
100
water
sol
C,,"
mol/m3
1.7
X
10"
2.4
X
8.5
X
10"
8.5
X
10"
6.9
x
10-3
1.3
x
10-4
1%
H,
KO,
Pa
m3/mol
6.0
88
3.8 0.43
3.8
0.17
6.0 2.9
6.0 53
5.0 6.2
on homogeneous subsamples (105 "C, 24 h). Sulfuric acid
cleanup was followed by Florisil column chromatography.
Samples were analyzed with a Perkin-Elmer Sigma-3B
chromatograph, using a 30 m
X
0.2 mm (i.d.) SPB-5
bonded-phase (0.25-pm film thickness) fused-silica capil-
lary column from Supelco. Carrier gas: argon-methane
95/5%,
100
kPa, split ratio 66/1; injector and EC detector
temperatures were 220 and 280 "C, respectively; oven
temperature 100 "C for
10
min to 280 "C at 3 "C/min and
maintained for 40 min.
Statistical Treatment
of
the Data.
A
log-probit
analysis was performed on the foliage concentration of
samples from the same area according to a BASIC com-
puter program suggested by Trevors
(18)
but slightly
modified. This statistical approach was used by Bacci et
al.
(1
7)
and recently has been suggested as appropriate by
Travis and Land
(19)
and by Helsel (20).
A
median
C50
was calculated for each group
of
samples.
The values corresponding to probit 4 and 6
(C16-C84),
indicating the range around the median where -68% of
the results were expected, were also calculated; from these
values the slope of the sample distribution line was ob-
tained.
A
x2
test gave an indication of the homogeneity
of the sample population and was significant in almost all
cases.
Physicochemical Parameters.
A
review of the liter-
ature was performed in order to estimate the main pa-
rameters relevant to understanding environmental dis-
tribution processes. Table
I1
shows data on vapor pressure,
water solubility, and octanol-water partition coefficients
(log
Kow)
critically selected from a number of literature
sources (5,21-27).
Vapor pressure data are in good agreement with a series
of experimental values recently produced by B. Rordorf
(personal communication).
Results
Mean concentrations, calculated as
C50,
of the six
molecules, for the 26 sample sites, are reported in Table
111. The
x2
values and the slopes of the sample distri-
bution lines are also shown in the table.
For hexachlorobenzene (HCB) and for the sum of hex-
achlorocyclohexanes (HCHs) and DDTs a log-probit
analysis has also been performed on the mean values for
the different sites in order to obtain a more easily com-
parable picture of the global range of values.
The distribution lines, reported in Figure
2,
indicate that
HCB shows relatively low concentrations, with a
C50
of
0.12 ng/g. The
C50
values for total HCHs and DDTs are
more than
1
order of magnitude higher.
The concentrations in plant foliage here reported are
consistent with the published data; see, for example, pine
needles from several samples in Germany (28), Italy
(15),
and other European countries
(11),
lichens from Sweden,
I
1
10
1M
1M)O
10Km
PSI^'
Figure
3.
Log-probit distribution of air concentration values for HCB
and the sum of HCHs and DDTs taken from the literature
(2,
5,
7,
33-35).
C50
values and the slopes
(S)
are also reported.
Norway, and France
(29-311,
and mango foliage from
Colombia
(32).
Discussion
Chlorinated hydrocarbons have been found in foliage in
all
parts
of the world. The concentration means and ranges
are variable according to the areas studied, but high
enough to permit reliable analysis and thus the use of
foliage
as
a biomonitor of presence of chlorinated hydro-
carbons even in remote areas where problems may arise
for
air
sampling. Conceptually, this kind of approach could
be used to monitor other persistent chemicals with com-
parable circulation patterns.
As
foliage contamination from organochlorinated hy-
drocarbons is believed to depend on the concentration in
the atmosphere
(11,15),
a survey of the literature has been
made in order to compare global air concentrations with
global plant concentrations measured in this work. Figure
3 shows the levels in the atmosphere taken from the lit-
erature
(2,5,
7,
33-35)
treated with the same log-probit
statistical analysis. Results indicate a different ranking
among the compounds in comparison with foliage. In air
the lowest mean values are for DDTs, in the middle in
HCB, and the highest values are for HCHs.
From the global levels in foliage and in air, a biocon-
centration factor (BCF) can be calculated as the ratio
between the
C50
in the two compartments. The values
obtained are in good agreement with those experimentally
measured in simulation chambers by Bacci et al. (12), as
shown in Table IV. This seems to confirm that some
Environ. Sci. Technol.,
Vol.
25,
No.
8,
1991
1401
Table
111.
Mean Concentrations
(CSO
in ng/g Dry Weight) and Statistical Parameters
(xz),
Degrees of Freedom (DF), and Slope
(S)
of
the Log-Probit Line for the Organochlorines
in
the
26
Sample Sites‘
site
1.
Spitabergen
C50
DF
S
2. Iceland
3. Scandinavia
X2
X
C50
X2
DF
S
4.
Foroyar
C50
X2
DF
S
5. Italy
6. New Delhi
X
C50
X2
DF
S
7. Nepal
C50
X2
DF
S
8.
Nepal Mountains
C50
DF
X2
S
9. Everest
C50
DF
X2
S
C50
10. Guatemala
X2
DF
S
C50
11.
Mali-Guinea
X2
DF
S
C50
12. Delta Amacuro
HCB
1.00
4.98
2.7
1.47
0.68
4.36
2.6
0.27
0.42
6
1.6
1.41
17
15
<0.1
0.10
4.10
2.4
0.25
6.09
2.6
0.48
0.63
3
1.8
0.14
0.28
4
1.4
<0.1
13
24
<o.
1
X2
DF
S
C50
<0.1
DF
S
13. Benin-Burkina Faso
X2
wHCH
3.42
9.44
2.2
4.90
8.59
3.82
2.8
0.81
5.29
6
2.3
26.93
17
15
106.9
0.19
5
2.4
21.52
28.42
18
3.1
35.74
19.42
28
2.7
9.50
0.69
3
1.7
0.45
0.34
4
1.6
0.50
6.89
9
2.2
7.58
1.43
4
3.7
0.60
2.50
4
2.3
PP’-
0,P’-
P,P‘-
Y-HCH DDT DDT DDE
0.52 0.30 ND 0.20
14.54 7.82 16.40
17 14 14
1.8 1.6 1.7
0.78 0.39 ND 0.10
3.69 1.60 0.90 0.40
2.05 3.60 8.61 7.18
15 14 14 14
2.7 3.0 3.0 3.3
0.66 2.90 ND 0.70
0.50 2.45 2.47
66 6
2.0 2.5 4.0
9.95 12.40 ND 8.40
13.55 77.80 10.80 21.00
0.60 1.10 0.90 1.70
5555
3.3 1.7 1.4 1.9
3.46 13.70 2.40 1.90
9.29 15.46 9.20 7.15
18 18 18
18
3.5 3.1 3.0 2.4
4.47 10.50 4.00 1.60
9.68 3.61 5.15 11.87
28 28 29 28
2.3 2.4 2.0 2.2
1.15 2.10 1.80 0.30
0.34 0.75 1.59 1.17
3333
1.8 2.4 2.0 2.5
0.32 2.90 0.40 1.10
0.55 0.54 0.01
0.10
4444
2.2 2.4 3.5 2.8
0.20 37.00 4.30 8.10
5.12 2.25 2.44 1.42
9999
2.2 6.2 8.2 4.8
0.30 27.50 2.10 2.60
1.68 0.45 1.58 1.15
4444
4.9 8.5 5.0 8.8
<0.1 5.10 1.00 1.00
0.80
0.90 1.70
444
4.7 5.3 11.0
P,P’-
0,P’-
P,P’-
site HCB wHCH Y-HCH DDT DDT DDE
14. Ghana Suhum
C50 <0.1 0.30 2.80 2.40
0.80
0.40
X2
12.60 8.60 2.50 3.50 11.10
DF 17 17 17 17 17
S
1.7 2.7 2.1 2.0 1.9
C50 <0.1 0.69 0.35 3.30 0.70 1.60
X2
0.38 0.49 0.82 0.82 1.19
DF 2 2222
S
1.6 1.9 1.8 1.4 4.9
C50
<O.l
0.30 1.00 15.00 1.50 1.90
X2
23.60 26.50 44.00 26.10 19.70
DF 29 29 29 29 29
S
1.6 1.7 2.9 3.1 2.3
C50
<0.1
41.39 0.15 52.20 7.70 6.50
X2
2.11 6.27 3.20 2.98 5.81
DF 13 13 13 13 13
S
5.3 6.1 10.3 7.8 10.6
C50 0.52 7.93 0.78 4.00 1.00 1.10
X2
7.40 4.54 9.75 18.40 8.50 8.10
DF 20 20 20 20 20 20
S
2.0 2.4 4.4 2.7 4.6 2.1
X
<0.1
1.45
0.88
13.50 2.10 6.70
C50
<0.1
2.71 0.78 13.80 5.70 25.44
X2
0.75 0.44 1.06 1.45 0.48
DF 2 2222
S
2.4 1.3 2.0 1.6 1.7
C50 0.18 1.10 0.79 1.20 0.40 0.40
X2
1.16 1.23 1.31 0.97 1.28 1.05
DF 6 6 6666
S
1.7 1.9 2.1 2.9 3.6 1.8
X
0.12 0.58 0.77 4.40 <0.1 0.60
C50
<0.1
0.19 <0.1 ND ND ND
X2
1.39
DF 7
S
1.5
C50 0.15 0.21 <0.1 0.15 0.20 <0.1
X2
0.64 0.68 0.51 1.69
DF 3 3
s
1.5 2.7 2.0 1.9
C50 0.49 0.32 0.71 0.30 ND 0.20
X2
2.23 3.55 1.61 1.50 2.50
DF 9 9 99 9
S
C50 0.30 0.17 0.04 0.20 ND 0.20
x2
3.21
1
3.42 2.74 3.27 4.76
DF
8
8 88 8
S
2.’7 1.6 2.0 2.0 2.0
15. Ivory Coast
16. Ghana Accra
17.
Amazonas
18. Mount Kenya
19. Nairobi, Kenya
20. Mombasa, Kenya
21.
Bolivia
22. Capetown
23. Tristan Da Cunha
24. Tierra del Fuego
22
25. Antarctic Peninsula
2.0
1.6 1.7 1.5 2.5
26. Kay Island
a
ND, not detected. A geometric mean
(x)
is reported if samples were too few for a complete statistical evaluation.
Table IV. Values of Foliage-Air BCF for HCB, HCHs, and
DDTs Calculated as Mass Ratio between Global Mean
Concentrations
(C50)
in Foliage and Air, Compared to
Experimentally Measured Values in Simulation Chambers
(12)
HCB
HCHs
DDTs
BCF (C50 ratio)
1.3
X
lo3
1.1
X
lo4
2.4
X
lo5
BCF (exptl) 1.9
X
lo3
4.6
X
lo3
(a)
1.9
X
lo5
(P,p’-DDT)
3.4
x
103
(7)
1.3
x
105 (P,P’-DDE)
aspects of the global behavior of these molecules can be
predicted from small-scale experiments and/or theoretical
evaluations.
It
could thus be suggested that vegetation can be used
as
an indicator of
air
contamination, although some sources
of
variability exist and cannot be controlled.
Possibly the use of old vegetation takes into account the
different rates of absorption/release kinetics, but other
pitfalls
or
sources of error (e.g., chemical reactions,
translocation, local meteorological conditions) cannot be
evaluated.
In the following paragraphs, some comments on the
single substances will be presented.
Hexachlorobenzene
(HCB).
According to Atlas and
Giam
(4),
HCB
is, along with
HCHs,
one of the predom-
inant chlorinated hydrocarbons in the marine atmosphere,
with a relatively homogeneous distribution in the two
1492
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1991
05
d
I//
HCB
0211
-
-
Sd
I
02‘
1
__-*
p?-----
.
022
,
D
DTs
”4
01
-
-
__
----_
02-
-3..
.
04
\
T5
,/-
021
I
HCH,
028
1
100
lo
nglg(dw)
Figure
4.
Distribution of HCB and sum of
DDT
and sum of HCH mean
concentrations in the
26
sample sites as a function
of
the latitude.
Circled points represent mountain sites.
hemispheres. In contrast, a high interhemispheric gradient
has been suggested by Wittlinger and Ballschmitter
(3)
but
this is based only on
a
limited quantity of data.
Differences in atmospheric distribution between com-
pounds are related to differences in source strength and
in atmospheric residence times. On the basis of its
physicochemical properties, in particular its relatively high
Henry’s law constant, it is expected that HCB will have
an atmospheric residence time longer than other chlori-
nated hydrocarbons. Consequently, Atlas and Giam
(4)
predicted and found a small interhemispheric gradient.
This hypothesis has also been recently proposed in a wide
literature survey carried out by GESAMP
(5)
and is con-
firmed by Figure
3,
which indicates that atmospheric
concentrations of HCB extend over a relatively small
7
L
F
E
N
s
s
LA-
Figure
5.
Global distribution
of
mean temperatures as a function of
latitude and height. The four mountain sites considered in the present
survey are indicated.
.28
-4
.I
.5
1
HCE
10
ngg(dw)
0.1
Figure
6.
Relationship between HCB mean concentrations and mean
temperature
of
the sampling sites.
range. Concentrations of HCB in plants verify this hy-
pothesis, even if the differences among the slopes of the
various molecules are less evident (Figure
2).
A
better explanation of the variability of HCB concen-
trations in plants is given in Figure
4.
From the figure
it appears that, together with a slight difference between
hemispheres, a difference between low and high latitudes
is more evident. In tropical areas HCB concentrations in
plants are always negligible and increase toward cold re-
gions. Relatively high values in tropical or subtropical
areas were found only in high-altitude samples (Nepal,
Kenya, etc.).
On the basis of an approximate distribution of mean
temperature in function of latitude and height (Figure
5)
it is possible to find a good relationship between HCB
concentrations and annual temperature averages, the only
exception being Italian samples (Figure
6).
This trend can be explained by a “cold condenser” effect,
particularly important with a volatile molecule such as
HCB. These data indicate that the observed concentra-
tions of HCB in the areas sampled in this survey are the
result
of
a long-term distribution, regulated by global
processes and physicochemical properties more than by
direct contamination.
Italian data appear as outliers due to the fact that they
derive from the only highly developed and industrialized
temperate area included in the survey, where contamina-
tion due to use can be considered the prevailing process.
HCB levels in Italian pines are comparable to those in
plants from other developed countries (United States,
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1991
501
/26
\
30.
W
I3
z
n
20.
10.
,
I
40
I
)+
I
19
\
\
,'ni.,
\
'.",
,'
\
I,
\
015
\
010
\,.21
e4
024
-2
0.1
1
10
100
DDTs
ngig
cdw)
Flgure
7.
Relationship between DDT concentrations in foliage and the
percentage
of
p,p'-DDE.
Yugoslavia)
(15),
but are not reported in this survey due
to different sampling methodology.
DDTs.
The most common DDT forms in the environ-
ment are p,p'-DDT, its isomer o,p'-DDT present in the
technical product, and its degradation product p,p'-DDE,
though in some cases other degradation products, such as
DDDs, can be present at significant levels.
Total DDT introduced before the
1972
ban should exist
primarily in the form of degradation products (mainly
DDE)
(36).
However, DDT is still heavily used in several
developing countries, accounting for the nonhomogeneous
distribution of total DDT concentrations in the atmosphere
(see slope in Figure
3).
Current usage of DDT also affects
concentrations measured in foliage. Higher concentrations
were measured where an intensive use is still present or
took place in the recent past.
In contrast to HCB, DDT plant concentrations are
highest in tropical and subtropical areas (Figure
4).
In Figure
7
a relationship between the total amount of
DDTs measured in foliage and the percent of DDE is
evident. The highest values of DDT concentrations with
low percentage of DDE are typical of areas where DDT
is still in use in large amounts (e.g., India), whereas low
levels of total DDTs correspond, in general, to high DDE
percentages, and this can indicate long-range, indirect
contamination. Only Italy and Kenya behave as outliers,
being areas of high but not recent contamination.
Total DDT distribution is not related to temperature,
unlike HCB. Nevertheless, for o,p'-DDT, a relationship
with temperature was observed (Figure
8).
This is in
agreement with the physicochemical properties of the
molecules (Table 11) and in particular with the high
Henry's law constant of o,p'-DDT, although very cold areas
are not considered in the figure due to the low levels of
DDTs that make unreliable the calculations of the per-
centage of the DDT forms.
Hexachlorocyclohexanes
(HCHs).
HCHs are used
in the form of nearly pure
y
isomer (lindane) or as tech-
nical product, a mixture of five isomers where the
a
form
is the prevalent with an amount of
-55-80%.
At
present,
the pure
y
form is the most widely used but large amounts
of the technical product are still produced and employed,
mainly in the Far East
(7).
HCHs show relatively high concentrations in the at-
mosphere and a gradient between the Northern and
Southern Hemispheres has been observed
(3-5).
Several authors indicated a-HCH as the major compo-
nent
of
total HCH
(I,
7,8).
Bidleman et a].
(7)
proposed
two possible explanations: a long-range transport from
1494
Environ. Sci. Technol.,
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25,
No.
8,
1991
022
-20
-10
0
10
20
30
Flgure
8.
Relationship between the percentage of o,p'-DDT and the
mean temperature of the sampling sites.
TEMPERATURE
OC
developing countries where the technical product is largely
used, and an isomerization process from the
y
to the
a
form.
On the other hand, Atlas and Giam
(35)
hypothesized
that the ratio a-HCH/y-HCH is an indication of the age
of an air parcel.
A
high
a/y
ratio indicates older air. They
observed that air masses with trajectories directly from
Europe, where only the
y
form is used, had an
a/y
ratio
of
-511,
while background air had ratios near
50/1.
Foliage data measured in this survey show a relatively
high
C50
(Figure
21,
comparable with the DDT value, and
a flat slope, indicating a very wide range of concentrations.
The geographical distribution (Figure
4)
confirms a
gradient between Northern and Southern Hemispheres for
total HCHs. The mean value
(C50)
of Northern samples
is
-5
times higher than those of the Southern Hemisphere.
The ratio between
a
and
y
isomers confirms, with some
exceptions, the prevailing role of a-HCH. Nevertheless
it
is very difficult to understand distribution patterns
because the relative amounts of
a
and
y
isomers are af-
fected by at least two factors: the present use of the
technical product or of the pure lindane, and the isom-
erization of
y-
to a-HCH. The concurrence of those two
factors can give very conflicting results. For example, the
high
a/
y
ratios observed in some areas
of
Latin America
(Amazonas, Delta Amacuro) can be assumed to be an in-
dication of a strong use of technical product rather than
of old contamination; in fact, the flat slopes observed in
these extended areas seem to be an indication of recent
and direct contamination. In contrast, the very low levels
of
cy/y
ratio in some African areas indicate a recent use
of the pure
y
form. In conclusion, the levels of HCHs and
the ratios between the two forms seem to be strongly af-
fected by the present high use in different formulations
rather than by long-range distribution processes and by
the role of physicochemical properties, which are very
similar for both isomers (Table
11).
In the interpretation of the global distribution
of
per-
sistent organic chemicals in vegetation based on physico-
chemical properties,
it
is important
to
use data from areas
without relatively recent usage of the chemical. For HCB,
only the Italian samples can be assumed not to have this
characteristic. Thus, the main features of the observed
distribution of HCB appear influenced more by long-range
processes regulated by molecular properties and environ-
mental phenomena (e.g., cold condenser effect) than by
contamination due to use.
For HCHs and DDTs the problem is more complex due
to the actual use of these molecules, in particular in de-
veloping countries from which most of the samples exam-
ined in this survey derive. Therefore only partial deduc-
tions can be made.
Conclusions
The present work and other literature on chemicals in
vegetation indicate the following general conclusions: (a)
there is a linear relationship between concentration
of
chemicals in foliage and in air
(12),
and the role of root
translocation is, for the studied compounds, negligible
(10);
(b)
chlorinated hydrocarbons can be detected in plant
foliage from different species and the choice of the species
is relatively unrelevant in relation to the aim of the in-
vestigation
(I@,
especially when dealing with global dis-
tribution; (c) concentration in foliage is a suitable monitor
of atmospheric contamination
(11,
15,
31);
(d) parent
compound and metabolite ratios can provide information
on the age of contamination
(16, 36);
(e) slopes of the
frequencies
of
concentration (probits) within groups of
samples (Le., from the same geographic1 areas) can give
indications of actual use and redistribution
(17);
(f)
con-
centrations in lichens and mosses in Antarctica have been
studied with the assumption that this area would have
been the cleanest part of the world, being the farthest from
the technological world
(16);
the findings however did not
confirm this hypothesis
(13,
at least for certain substances
(i.e.,
HCB);
(g) chlorinated hydrocarbons distribute and
cycle between air-water and air-soil by means of depos-
ition-volatilization periods, with the so-called "grasshopper
effect"
(37);
(h) according to literature data, substances
with subcooled liquid vapor pressure
(A)
higher than
Pa tend
to
be distributed mainly in the vapor phase of the
atmosphere, confirming the essential role of vapor move-
ments in the global transport of these chemicals
(38);
(i)
tropical areas have been identified, mainly due to climatic
and meteorological reasons, more
as
contamination sources
than as contamination receivers; this last role is more
suited to the cold areas (cold condenser effect)
(17).
Acknowledgments
We thank every person
or
organization contributing to
the samples collection and
B.
Rordorf for providing un-
published data.
Literature
Cited
Atlas, E. L.; Giam, C.
S.
Science
1981,211, 163-165.
Tanabe,
S.;
Hidaka, H.; Tataukawa, R.
Chemosphere
1983,
Wittlinger, R.; Ballschmitter,
K.
Fresenius
J.
Anal. Chem.
Atlas, E. L.; Giam, C.
S.
In
The role of air-sea exchange
in geochemical cycling;
BouabMenard,
P.,
Ed.; NATO-AS1
Series C
185;
Reidel Publishing Co.: Dordrecht, The
Netherlands,
1986;
pp
295-329.
GESAMP, Joint Group of Experts on Scientific Aspects
of Marine Pollution.
Rep. Stud.-GESAMP
1989,
No.
38,
1-111.
Tateya,
S.;
Tanabe,
S.;
Tatsukawa, R. In
Toxic contami-
nation in large lakes;
Schmidtke, N. W., Ed.; Lewis Pub-
lishers: Chelsea, MI,
1988;
Vol. 111, pp
273-281.
Bidleman,
T.
E.;
Wideqvist,
U.;
Jansson, B.; Soderlund, R.
Atmos. Environ.
1987, 21, 641-654.
12, 277-288.
1990,
336,
193-200.
(8)
Patton, G. W.; Hinckley, D. A.; Walla, M. D.; Bidleman,
(9)
Buckley, E. H.
Science
1982, 216, 520-522.
T.
F.; Hartgrave,
B.
T.
Tellus
1989, 41B, 243-255.
(10)
Bacci, E.; Gaggi, C.
Bull.
Environ. Contam. Toxicol.
1985,
(11)
Ericksson, G.; Jensen,
S.;
Kylin, H.; Strachan, W.
Nature
(12)
Bacci, E.; Calamari, D.; Gaggi, C.; Vighi, M.
Environ. Sci.
(13)
Riederer,
M.
Environ.
Sci.
Technol.
1990, 24, 829-836.
(14)
Trapp,
S.;
Matthies,
M.;
Scheunert, I.; Topp, E. M.
Enuiron.
(15)
Gaggi, C.; Bacci, E.; Calamari,
D.;
Fanelli, R.
Chemosphere
(16)
Bacci,
E.;
Calamari, D.; Gaggi,
C.;
Fanelli, R.; Focardi,
S.;
(17)
Bacci, E.; Calamari, D.; Gaggi,
C.;
Biney, C.; Focardi,
S.;
(18)
Trevors,
J.
T.
Bull.
Environ. Contam. Toxicol.
1986,
37,
(19)
Travis, C. C.; Land,
M.
L.
Enuiron. Sci. Technol.
1990,24,
(20)
Helsel,
D.
R.
Environ. Sci. Technol.
1990,24, 1766-1774.
(21)
Hansch, C.; Leo,
A.
J.
Substituent constants for correlation
analysis in chemistry and biology;
John Wiley: New York,
1979.
(22)
Lyman, W. J.; Reehl, W. F.; Rosenblatt, D.
H.
Handbook
of
chemical property estimation methods;
McGraw-Hill
Book
Co.:
New York,
1982.
(23)
Suntio, L. R.; Shiu, W.
Y.;
Mackay,
D.
Seiber,
J.
N.;
Glotfelty, D.
Rev. Environ. Contam. Toxicol.
1987, 103,
(24)
Worthing, C. R.; Walker,
S.
B.
The Pesticide Manual,
8th
ed.; The British Crop Protection Council: Lavenham,
Suffolk,
U.K.,
1987.
(25)
Verschueren, K.
Handbook of environmental data on
or-
ganic chemicals,
2nd ed.; Van Nostrand Reinhold Co.: New
York,
1983.
(26)
Morris, C.
R.;
Cabral,
J.
R.
P.
Hexachlorobenzene: pro-
ceedings
of
an international symposium;
IARC Scientific
Publication
77;
International Agency for Research on
Cancer: Lyon, France,
1986.
(27)
De Bruijn, J.; Busser, F.; Seinen, W.; Hermens,
J.
Environ.
Toxicol. Chem.
1989,8, 499-512.
(28)
Reishl,
A,;
Reissinger, M.; Hutzinger,
0.
Chemosphere
1987,
(29)
Villeneuve,
J.
P.;
Holm,
E.
Chemosphere
1984, 13,
(30)
Carlberg, G.; Baumann-Ofstad, E.; Drangholt, H.; Steinnes,
(31)
Villeneuve,
J.
P.; Fogelquist,
E.;
Cattini, C.
Chemosphere
(32)
Schrmipff,
E.
Water, Air, Soil Pollut.
1984,21, 279-315.
(33)
Guicherit, R.; Schulting,
F.
L.
Sci.
Total Enuiron.
1985,43,
(34)
Nakano, T.; Tasuji,
M.;
Okuno,
T.
Chemosphere
1987,16,
35, 673-681.
1989, 34, 42-44.
Technol.
1990,24, 885-889.
Sci. Technol.
1990,24, 1246-1251.
1985, 14, 1673-1686.
Morosini,
M.
Chemosphere
1986, 15, 747-754.
Morosini,
M.
Chemosphere
1988,
17,
693-702.
18-26.
961-962.
1-59.
16, 2647-2663.
1133-1138.
E.
Chemosphere
1983,12, 341-356.
1988,17,399-403.
193-219.
1781-1786.
(35)
Atlas,
E.
L.;
Giam, C.
S.
Water, Air, Soil Pollut.
1988,38,
19-36.
(36)
Rapaport, R. A.; Urban, N.
R.;
Capel,
P.
D.;
Baker,
J.
E.;
Looney, B. B.; Eisenreich,
S.
J.; Gorham,
E.
Chemosphere
(37)
Mackay, D.; Paterson,
S.;
Schroeder, W. H.
Environ. Sci.
Technol.
1986,20,810-816.
(38)
Bidleman,
T.
F.; Billings, W. N.; Foreman, W.
T.
Environ.
Sci. Technol.
1986,20, 1038-1043.
1985,14, 1167-1173.
Received for review January
23, 1991.
Revised manuscript re-
ceived April
18, 1991.
Accepted April
22,
1991.
Environ.
Sci.
Technol.,
Vol.
25,
No.
8,
1991
1495
... At the end of the 20th century, most of the studies were developed to characterize the concentration of DDT and its congeners on soils and sediments in agricultural land and rivers [4][5][6][7][8][9][10]. In these, the forms of DDTs sampled were p.p'-DDT and o.p'-DDT, the congeners mainly sampled were p.p'-DDD and p.p'-DDE. ...
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... The study of utilization of pollutant concentrations in plant life as a possible pointer of atmospheric and soil contamination levels is referred to as biomonitoring (Paterson et al. 1990;Kylin 1994;Simonich and Hites 1994;Smith and Jones 2000). Many species are being used for biomonitoring of organic pollutants, for example, Scots pine (Pinus sylvestris), spruce (Picea abies), and saxifrage (Saxifraga oppositofolia) (Eriksson et al. 1989;Calamari et al. 1991;Jensen et al. 1992, Tremolada et al. 1996Safe et al. 1992;Strachan et al. 1994;Juuti et al. 1995;Reischl 1988;Weiss 1998;France et al. 1997). Moreover, conifers are also widely used for detecting different patterns of organic pollutants geographically (Eriksson et al. 1989;Jensen et al. 1992;Tremolada et al. 1996;Weiss 1998) and for the investigation of polycyclic aromatic hydrocarbons (PAHs) in plants (Kylin 1994;Simonich and Hites 1994;Wagrowski and Hites 1996;Bakker 2000). ...
Chapter
Under abiotic stress, the production of reactive oxygen species (ROS) such as hydrogen peroxide or superoxide causes harmful effects on the survival of rhizobacteria, which have an important role in the growth and yield of various crop plants. To cope with ROS stress, rhizobacteria activate certain regulons that are controlled by the OxyR, PerR, or PerR-like homolog and SoxR transcription factors. All these sense peroxides during the oxidation of iron, manganese, zinc, nickel, and other moieties and stimulate overlapping sets of proteins, which defend their weak metalloenzymes. It is also evident that these OxyR, PerR, or PerR-like and SoxR homologs help in detecting electrophilic compounds. In most of the bacteria, various regulatory genes control the redox-cycling compound, whereas in some cases, it protects in contradiction of the same causes. After oxidation of iron-sulfur compounds, the regulons prompt proteins that dispense with, discharge, or adjust them and instigate compounds that defend the cells against oxidative stress. The present book chapter comprehensively describes the role of different transcription factors in scavenging ROS stress faced by so-called rhizobacteria. Moreover, research gaps with prospects for further investigation are also mentioned.
... The study of utilization of pollutant concentrations in plant life as a possible pointer of atmospheric and soil contamination levels is referred to as biomonitoring (Paterson et al. 1990;Kylin 1994;Simonich and Hites 1994;Smith and Jones 2000). Many species are being used for biomonitoring of organic pollutants, for example, Scots pine (Pinus sylvestris), spruce (Picea abies), and saxifrage (Saxifraga oppositofolia) (Eriksson et al. 1989;Calamari et al. 1991;Jensen et al. 1992, Tremolada et al. 1996Safe et al. 1992;Strachan et al. 1994;Juuti et al. 1995;Reischl 1988;Weiss 1998;France et al. 1997). Moreover, conifers are also widely used for detecting different patterns of organic pollutants geographically (Eriksson et al. 1989;Jensen et al. 1992;Tremolada et al. 1996;Weiss 1998) and for the investigation of polycyclic aromatic hydrocarbons (PAHs) in plants (Kylin 1994;Simonich and Hites 1994;Wagrowski and Hites 1996;Bakker 2000). ...
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Zinc (Zn) is a basic metal that all life forms need in minimal quantity for optimum growth and development of crops. Zn is an integral part of their structural and catalytic components such as proteins and enzymes and participates in redox reactions occurring in living organisms. Around one-third of the world population is Zn deficient. In the human diet, cereals are the main source of Zn, which get Zn from the soil. To combat Zn deficiency in the human diet and for the proper function of the plants, various strategies have been devised. For example, development crop seeds with the ability to accumulate Zn in edible portion through breeding strategies and novel state-of-the-art genetic engineering approaches. However, these strategies are costly and require a long time. In agronomic strategies, there is soil/foliar application of Zn using chemical fertilizers, of which solubility in soil and their bioavailability is the main issue. To combat this problem, an economical and eco-friendly strategy is required to enhance Zn availability to the crop plants. In this regard, Zn-solubilizing bacteria have the potential to mobilize the fixed Zn in the soil through various mechanisms, can serve as potential plant stress mitigators, and ultimately would result in the alleviation of Zn deficiency to the crop plants and Zn biofortification at the same time. In this chapter, we highlight the status of Zn deficiency and its causes in agricultural soils around the world, the role of plant growth-promoting rhizobacteria in the alleviation of Zn stress in plants, and their future perspectives.KeywordsZnBiofortificationPGPRZn-solubilizing PGPRRhizobacteriaGrainsCereals
Article
In 1996 high dichlorodiphenyltrichloroethane (DDT) concentrations were found in Lake Maggiore (Italy) fish and sediments. DDT was produced by a chemical company located in a subalpine valley (Ossola valley, Piedmont Region, Italy), and ended up in the Toce River, a tributary of Lake Maggiore. In the area surrounding the chemical plant, high DDT concentrations in soil and vegetation were found after subsequent investigations. The quantification of the release from contaminated soil and the following migration toward downwind areas, deposition to the soil, and further evaporation plays an important role in understanding future DDT trends in soil and the atmosphere. To study this phenomenon, soil, and vegetation from Ossola Valley were monitored in 2001 and 2011. The concentration values obtained (soils: 0.05 to 1 μg/g; vegetation 2–100 ng/g), allowed to reconstruct the contamination gradient in the valley and were used to develop and calibrate a spatially resolved multimedia fugacity model. The model accounts for spatial and temporal dynamicity of environmental characteristics such as wind speed and direction, variable air compartment height etc., and simulates the fate and transport of chemicals on a local scale. The dynamic emission of DDT (about 13,000 kg for the 50 y production time) to the air was estimated and utilized for a 100-year simulation (from 1948 to 2048). The results obtained allowed to understand the temporal and spatial pattern of DDT contamination for a long period at a local scale as well as the potential contribution as a source potentially affecting sites at larger distances.
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Agricultural ecosystems contain many harmful organic pollutants that not only can stop human life but threaten plant life and pose dangers to its integrity, affect health, and disrupt various functions. The organic pollutants mainly include antibiotics, herbicides, polychlorinated biphenyls (PCBs), bisphenol A (BPA), polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans (PCDD/Fs). This chapter identifies some key areas and issues necessary to understand and focus on organic pollutants. Numerous research studies have focused on the effects and accumulation of organic pollutants in crops and their potential to disturb the food chain. Moreover, much emphasis has been put on different uptake and driving mechanisms behind organic pollutants, and efforts are directed to discover more effects at a molecular level. These commonly found organic pollutants are responsible for disrupting various plant parts and functions such as membranes, nuclear functions, uptake functions, and other anomalies. Similarly, these organic pollutants have the potential to induce genotoxic, carcinogenic, xenobiotic, and endogenic effects. It is considered to be a large area of research with many singularities yet to be discovered. This study identifies certain existing knowledge that can illuminate existing issues and motivate future researchers and scholars to contribute their knowledge to address certain issues.
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Catalytic converter can contribute to global warming and to reduce emission of vehicle of engines. The transesterified Avocado oil is used as a fuel in a four-stroke diesel engine. The test fuels were prepared in different blends such as B10, B20 and B30. The aim of research work is to reduce emission and to improve the performance of the DI diesel engines, produced by the biodiesel blend. The catalyst materials used in catalytic converter are relatively low cost in comparison with conventional catalyst such as Palladium and Platinum. Basalt fiber is used as a substrate which is absolutely non-combustible. The performance and emission analysis are made.
Article
Persistent organic pollutants (POPs) and related chemicals are fascinating because of their combination of physical-chemical properties and complex effects. Most are man-made, but some also have natural origins. They are persistent in the environment, but they can be broken down variously by biodegradation, atmospheric reactions, and abiotic transformations. They can exist in the gas or particle phases, or both, in the atmosphere and in the dissolved or particulate phases, or both, in water. These combinations mean that they may undergo long-range transport in the atmosphere or oceans, or they may stay close to sources. Hence, emissions from one country are frequently a source of contamination to another country. They are also usually lipophilic, so-combined with persistence-this means they can accumulate in organisms and biomagnify through food chains. We all have a baseline of POPs residues in our tissues, even the unborn fetus via placental transfer and the newly born baby via mother's milk. POPs in biological systems occur in mixtures, so confirming effects caused by POPs on humans and other top predators is never straightforward. Depending on which papers you read, POPs may be relatively benign, or they could be responsible for key subchronic and chronic effects on reproductive potential, on immune response, as carcinogens, and on a range of behavioral and cognitive end points. They could be a factor behind diseases and conditions which have been increasingly reported and studied in modern societies. In short, they are endlessly fascinating to scientists and a nightmare to regulators and policy makers.
Article
To assess organochlorine compound (OC) contamination, its possible sources, and adverse health impacts on giant pandas, we collected soil, bamboo, and panda fecal samples from the habitat and research center of the Qinling panda (Ailuropoda melanoleuca qinlingensis)—the rarest recognized panda subspecies. The polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) concentrations were comparatively low which suggests that moderate sources of OC pollution currently. OC levels were lower in samples from nature reserve than in those collected from pandas held in captivity, and OC levels within the reserve increased between functional areas in the order: core, buffer and experimental. The distribution patterns, and correlation analyses, combined with congener distributions suggested PCBs and OCPs originated from similar sources, were dispersed by similar processes, being transported through atmosphere and characterized by historical residues. Backward trajectory analyses results, and detected DRINs (aldrin, dieldrin, endrin and isodrin) both suggest long-range atmospheric transport of pollution source. PCBs pose potential cancer risk, and PCB 126 was the most notable toxicant as assessed be the high carcinogenic risk index. We provide data for health risk assessment that can guide the identification of priority congeners, and recommend a long-term monitoring plan. This study proposes an approach to ecotoxicological threats whereby giant pandas may be used as sentinel species for other threatened or endangered mammals. By highlighting the risks of long-distance transmission of pollutants, the study emphasizes the importance of transboundary cooperation to safeguard biodiversity.
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Mango leaves, at the end of their natural cycle, collected in 71 sites of 5 different countries have been used for a study on the contamination by chlorinated insecticides (lindane, p,p'DDT and related compounds), HCB and PCBs in the terrestrial ecosystems of West Africa. The role of this region in the global circulation of these contaminants is briefly discussed.
Chapter
Carbon dioxide is, besides water, the main nutrient for plants and therefore for life on earth. In consequence of fossil fuel burning and human impact on the land biota, the atmospheric concentration of carbon dioxide is steadily increasing, which may lead to long-lasting changes of the global climate. These two facts explain the strong interest of scientists from many disciplines in this gas and its natural cycle.
Article
Measurement of untransformed (p,p'- and o,p'-) DDT in rain, snow, and peat indicates that input of “new” DDT continues over a large portion of eastern North America. Peat cores obtained from ombrotrophic bogs indicate that current atmospherically derived fluxes are about 10–20% of those which occurred during peak DDT usage (∼1960). Since DDT has been banned in North America and considering the magnitude of present fluxes, these residues must result from atmospheric transboundary transport. It is suggested that “new” DDT is being transported from neighboring areas where current use is substantial, Mexico and Central America.
Article
Lichens collected in the northern part of Sweden were analyzed over a 10-year period for chlorinated hydrocarbons. Results show a delay of 2–3 years between the production of PCBs and the deposition of these compounds in the lichen. They confirm the low solubility of PCBs in water and the predominance of atmospheric transport of these chlorinated compounds far away from industrialized areas.
Article
Uptake of several organic chemicals by growing barley was investigated in a closed laboratory model ecosystem (volume 9.4 L). To discriminate between root and foliar uptake, the soil was divided into test soil contaminated with 2 mg/kg 14C-labeled chemicals and unpolluted control soil. Air was exchanged at a rate of 10 mL/min. Concentrations of 14C chemicals in air, soil, roots, and shoots and bioconcentration factors were simulated with a mathematical model based on fugacity. Bioconcentration in the plant is dependent on transfer and the ratio of K(ow) and K(oc) values. Uptake into foliage is mainly from air for chemicals with a high K(ow) and a Henry's law constant high enough for volatilization. Chemicals with medium K(ow) are translocated with the transpiration stream. Metabolites are also taken up. Chemicals in the roots of the barley plants reach equilibrium with the soil, whereas those in foliage are in equilibrium with the air in most cases.
Article
PCBs and chlorinated hydrocarbon pesticides such as DDTs and HCHs (BHCs) were measured in air, water, ice and snow samples collected around the Japanese research stations in Antarctica and adjacent oceans during December 1980 to March 1982. The atmospheric concentrations of chlorinated hydrocarbons decreased in the transport process from northern lands to Antarctica, but the compositions of PCBs, DDT compounds and HCH isomers were relatively uniform throughout this process. Regional and seasonal variations were found in aerial concentrations of these pollutants at Syowa Station and adjacent seas in Antarctica. Chlorinated hydrocarbons were also detected in snow, ice, lake water and sea water samples, in which rather high concentrations were found in snow and ice samples. This suggests that snow and ice serve as media of supply of these pollutants into Antarctic marine environment.
Book
This handbook presents simple estimation methods for 26 important properties of organic chemicals that are of environmental concern. This book facilitates the study of problematic chemicals in such applications as chemical fate modeling, environmental assessments, priority ranking of large lists of chemicals, chemical spill modeling, chemical process design, and experimental design.
Book
Fully expanded and revised, this handbook lists over 2,000 organic chemicals while incorporating the extensive new information available on the environmental impact of these substances. New coverage is given on mixtures and preparations, individual chemicals, pesticides, detergents, pthalates, polynuclear aromatics, and PCBs. Special attention is given to pollutants of the abiotic and biotic environment, the correlation of bioaccumulation of chemicals to molecular structure, and the use of water solubility data to estimate the fate of chemicals in the environment. Data for each organic chemical includes synonyms, formula, properties, air and water pollution factors, and biological effects.