lake sediment evidence for long-range transported atmospheric pollutants on the tibetan plateau...
DESCRIPTION
Lake sediment evidence for long-range transported atmospheric pollutants on the Tibetan Plateau. Presented by Neil Rose at the "Perth II: Global Change and the World's Mountains" conference in Perth, Scotland in September 2010.TRANSCRIPT
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Lake sediment evidence for long-range transported
atmospheric pollutants on the Tibetan Plateau
Neil Rose, Handong Yang, Simon Turner, Rick Battarbee
Environmental Change Research Centre, University College London
Wu Guangjian, Yang Ruiqiang, Wang Xiaoping, Yao Tandong
Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing
Funded by
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Tibetan Plateau
‘Third Pole’
• North-west one of the most inaccessible
and least populated regions on Earth
• Presumption of pristine status
‘Water Tower of Asia’
• Source of the Ganges, Brahmaputra,
Indus, Yangtse, Yellow, Mekong and
Irrawady Rivers
‘Roof of the World’
• Averages >4000m altitude
• Above atmospheric boundary layer: long-
range pollutant sources
(e.g. intercontinental; hemispheric)
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Lake sediment record
Age
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Project aims:
To use lake sediments to provide data on the temporal and spatial
distribution of atmospherically deposited pollutants (trace metals, POPs,
fly-ash particles) across the Tibetan Plateau.
Allowing us to:
• assess the scale and rates of change of inputs for a suite of contaminants
across the region
• provide ‘baseline’ data to assess future changes in contamination of Plateau
freshwaters and background data for ecological impact studies
• undertake preliminary source apportionment for deposited contaminants
• determine long-term trends as a context for contemporary ITP monitoring
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
North Lakes Qinghai Hu
Keluke Hu
Ga Hai
Central Lakes Nam Co
Cuo Na
Cuo E
South Lakes Peku Co
Cuolong Co
Kemen Co
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
South
Cen
tral
Nort
h
Qinghai Hu Ga Hai
Cuo Na Tso Ur Nam Co
Chuolong Co Peku Co Kemen Co
Keluke Hu
2006
2007
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Sampling strategy
Multiple sediment and soil cores from each lake and catchment
Analyses include:
Lithostratigraphy (water, organic and carbonate content)
Chronologies
Sediment geochemistry (40+ elements; XRF)
Trace metals (Hg, Cd, Pb, Ni, Cu and Zn)
Persistent organic pollutants (PAHs, PCBs, PBDEs)
Fly-ash particles (SCPs and IASs)
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Results
Core chronologies Reliable chronologies (except Chuolong Co)
Great variety of accumulation rates; sub-decadal resolution
Time (AD)
1840 1860 1880 1900 1920 1940 1960 1980 2000
De
pth
(cm
)
0
10
20
30
40
50
TPNA1
TPNB1
TPNC1
TPCA3
TPCB1
TPCC1
TPSB1
TPSC1
Qinghai
Keluke
Gaihai
Cuo Na
Cuo E
Nam Co
Peku Co
Kemen Co
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Trace metals
(Pb)
TPSB1
0
5
10
15
20
25
0 5 10 15 20 25
Pb (µg/g)
Dep
th (
cm)
TPNA1
0
5
10
15
20
25
30
35
0 10 20 30
Pb (µg/g)
Dep
th (
cm)
TPNB1
0
5
10
15
20
25
30
35
40
0 10 20
Pb (µg/g)
Dep
th (
cm)
TPCA3
0
5
10
15
20
25
30
35
0 10 20 30
Pb (µg/g)
Dep
th (
cm)
TPCB1
0
5
10
15
20
25
30
35
0 10 20
Pb (µg/g)
Dep
th (
cm)
TPCC1
0
10
20
30
40
0 10 20 30
Pb (µg/g)
Dep
th (
cm)
TPSA1
0
5
10
15
20
0 1 2 3 4 5
Pb (µg/g)
Dep
th (
cm)
TPNC1
0
5
10
15
20
25
30
35
0 5 10 15 20 25
Pb (µg/g)
Dep
th (
cm)
TPSC1
0
5
10
15
20
25
30
35
40
45
0 5 10 15
Pb (µg/g)
Dep
th (
cm)
Northern lakes
Central lakes
Southern lakes
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Trace metals (normalised data for Qinghai)
TPNA1
0
5
10
15
20
25
30
0 1 2 3
Pb/K
Depth
(cm
)
TPNA1
0
5
10
15
20
25
30
0 10 20
Pb/Ti
Depth
(cm
)
TPNA1
0
5
10
15
20
25
30
0 0.2 0.4
Pb/LOI
Depth
(cm
)
TPNA1
0
5
10
15
20
25
30
0 50 100
Zn/K
Depth
(cm
)
TPNA1
0
5
10
15
20
25
30
0 50 100
Zn/Ti
Depth
(cm
)
TPNA1
0
5
10
15
20
25
30
0 50 100
Zn/LOI
Depth
(cm
)
Pb
Zn
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Lead Isotopes:
• Lead has four stable, naturally occurring isotopes: 204Pb (1.4%), 206Pb (24.1%), 207Pb (22.1%), and 208Pb (52.4%).
• Ratios of these isotopes varies in different minerals and sources.
• 206Pb / 207Pb ratios: Leaded petrol: 1.06 – 1.09
British Pb ore: 1.16 – 1.18
UK coal: 1.16 – 1.19
• Natural Pb ratios in uncontaminated sediments and peats typically 1.2 – 1.5
• Therefore Pb isotope ratio declines with anthropogenic signal.
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
0 0.5 1 1.5 2
Pb (EF)
Se
dim
en
t d
ep
th (
cm
)0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
1.13 1.14 1.15 1.16 1.17 1.18
206Pb/207Pb
Lead isotopes: Qinghai Hu (North)
1950
1860
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
0 0.5 1 1.5 2
Pb (EF)
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
1.13 1.15 1.17 1.19 1.21206Pb/207Pb
Lead isotopes: Co E (central)
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
(Sourc
e:
Jim
Knig
hto
n,
Cle
ar
Lig
ht
Image P
roducts
, C
opyrig
ht
2000)
Fly-ash particles
No
SCPs
Qinghai
1910
1930
1950
1970
1990
2010
0 10 20 30
SCP (no. cm-2
yr-1
)
Cuo Na
1910
1930
1950
1970
1990
2010
0 1 2 3
SCP (no. cm-2
yr-1
)
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Trace metals: Mercury fluxes
TPNA1
1850
1870
1890
1910
1930
1950
1970
1990
2010
0 10 20
Hg (mg/m2yr)
date
TPNB1
1850
1870
1890
1910
1930
1950
1970
1990
2010
0 10 20 30 40
Hg (mg/m2yr)
date
TPNC1
1890
1910
1930
1950
1970
1990
2010
0 20 40 60 80
Hg (mg/m2yr)
date
TPCA3
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
0 150 300 450 600
Hg (mg/m2yr)
date
TPCB1
1870
1890
1910
1930
1950
1970
1990
2010
0 20 40 60 80 100
Hg (mg/m2yr)
date
TPCC1
1850
1870
1890
1910
1930
1950
1970
1990
2010
0 10 20 30
Hg (mg/m2yr)
date
TPSB1
1940
1950
1960
1970
1980
1990
2000
2010
0 10 20 30
Hg (mg/m2yr)
date
TPSC1
1890
1910
1930
1950
1970
1990
2010
0 10 20 30 40
Hg (mg/m2yr)
date
Northern lakes
Central lakes
Southern lakes
• Significant increase in flux since 1970s
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Trace metals:
No
rth
Ce
ntr
al
So
uth
• Altitudinally enhanced oxidation of GEM to RGM by tropospheric air?
• RGM water soluble and hence more easily scavenged and deposited
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Persistent Organic Pollutants Fluxes: Qinghai
0 50 100 150
HCB
0 100 200 300 400
S HCHs1850
1870
1890
1910
1930
1950
1970
1990
2010
0 1000 2000 3000
Ye
ar
(AD
)
S PCBs
0 1000 2000 3000 4000
S DDTs
ng cm-2 yr-1
• Significant increase in contamination from all sources since 1970s
• Some evidence for earlier contamination. Global signal
ENVIRONMENTAL CHANGE RESEARCH CENTRE
Global Change and the World’s Mountains. Sept 2010
Conclusions
Lake sediment archives from across the Tibetan Plateau have shown:
• Evidence for contamination from hemispheric and global sources.
137Cs (weapons testing), mercury and persistent organic pollutant data
• Evidence for additional contamination in the north of the Plateau.
Trace metal (e.g. lead), Pb isotope and fly-ash particle data.
Regional sources such as Lanzhou? Xining?
• Contamination appears to be increasing rapidly.
Continued industrial development (China; N. India)
Suggests future increase in contamination is likely
Furthermore:
• Contaminant transport to the region may be exacerbated by changes to
monsoonal patterns