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Climate Change and fate of persistent organic pollutants (POPs) Gan Zhang Guangzhou Institute of Geochemistry The Chinese Academy of Sciences september [email protected] Persistent organic pollutants (POPs) • toxic chemicals, persistent in the environment • long-range transport via air, ocean currents etc • mostly hydrophobic, tend to accumulate in biota • Stockholm Convention: global POP source reduction Dirty Dozen!! Aldrin Chlordane Endrin PCDD Heptachlor HCB Toxaphene PCDF Mirex DDT Diendrin PCB 3 categories: HCH PAH PBDE • Pesticides • Industrial products • Unwanted by-products Temperaturedriven global distillation and transport? (UNEP, 2004) (Wania and Mackay, 1993) More POPs will transport to cryogenic environment ? Potential of glacier retreat to release POPs? - lessons learned from the Arctic AMAP, 2003 What if we go to lakes in the Tibetan plateau? E80o E90o E100o N40o N40o Mt .T Wudaoliang ® Star Sea an gg ula Co Ngoin Hi ma Yamzho Yumco Lhasa ® lay a N30o N30o Namjagbarwa ® I ® 75 Yamzho Yumco (羊卓雍错) Sediment core Reference site Warm & humid air flow 0 75 II 150 mile Co Ngoin (错鄂) Num Co (纳木错) Beautiful dating results !! Ln(210Pb-ex) 1 0 10 Ln(210Pb-ex) 1 1 10 Ln(210Pb-ex) 0 0 3 Depth/cm 3 3 6 6 9 6 9 12 15 a y = -9.9612Ln(x) + 20.967 2 R = 0.9798 9 b y = -5.8659Ln(x) + 7.4599 2 R = 0.9715 12 c y = -14.919Ln(x) + 15.235 2 R = 0.9832 Yamzho Yumco (羊卓雍错) Co Ngoin (错鄂) Star Sea (星星海) 0.31 cm/a 0.36 cm/a 0.46 cm/a 10 DDTs concs ‘rebound’! DDT concs increase after 1987 at Yamzho Yumco, after 1998 at Co Ngoin, after 1991 at Star Sea. DDE/DDTs ratios increase in the meantime, indicating recycled ‘weathered’ DDT. What happened in recent years in the plateau? -4.0 Wudaoliang Global warming Increasing evaporation Glacier retreat Melting of permafrost -5.0 T/oC Increasing precipitation -6.0 -7.0 1950 1960 1970 1980 1990 2000 1970 1980 1990 2000 2.0 Lhasa 1.0 T/oC 0.0 -1.0 -2.0 1950 1960 Glaciers in the plateau WWF, 2005 Glaciers retreated faster after in the 1990s than before. WWF, 2005 Global warming enhanced relocation of DDTs? DDT trapped in snow pack and ice may be released become available to be transported; Snow/ice water, intensified precipitation may also helps to flush and transport recycled DDT from soil to the lake basins. WWF, 2005 Yangtze River mud zone: 4 cores Coastal, YRE sourced - N4, N6: Yangtze River estuary - S3, S5: Down stream mud zone off Zhejiang province Lin et al., 2009 Coastal: average sedimentation rates from 1 to 3.4 cm/a, higher in the YRD than mud zone off Zhejiang province DDTs records in YRE (top) and mud zones off Zhejiang province • Sharp rebound and peaked at the layers of the 1990s • Peaks in late 1998 may be related to the severe watershed flood record in 1998 Lin et al., 2009 ‘Old’/recycled DDT input observed at sites N6 and S5 Strong land transform in the Taihu Lake region • Cultivated land loss coincided GDP sharp increase • 1992-1995 peak corresponded with DDT rebound well, suggesting a DDT relocation by enhanced soil-runoff. 50000 45000 40000 35000 30000 25000 Cultivated Land loss Area 20000 15000 10000 5000 0 1975 1980 1985 1990 GDP 1995 2000 2005 (data from official statistic books) Coupling between C cycle the fate of SVPPs? sum tri-PCB sum tetra-PCB 2.5 2.0 1.5 1.0 0.5 log conc (pg/g dw ) 3.0 0.0 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 20 40 60 80 100 0 20 % organic matter sum hexa-PCB 2.0 1.0 0.0 40 60 % organic matter 80 100 0 20 80 100 40 60 80 100 80 100 % organic matter sum octa-PCB 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 3.5 log conc (pg/g dw ) log conc (pg/g dw ) 3.0 20 60 sum hepta-PCB 4.0 0 40 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 % organic matter 5.0 log conc (pg/g dw ) sum penta-PCB 3.5 log conc (pg/g dw ) log conc (pg/g dw ) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 20 40 60 % organic matter 80 100 0 20 40 60 % organic matter Meyer et al. 2003 Relationship between soil concentration and OM content Soil with high total organic carbon TOC Dalla-Valle et al., 2004, 2005 Coupling between C cycle the fate of POPs Air SVPPs SVPPs Which is the ”exchangeable” fraction of SVPPs? SOM tourn-over Is the system a net sink for these pollutants? Under which conditions this system re-emit pollutants? Soil Luca Nizzetto 1 December 2009 25 Nizzetto et al., EST, 2010 Mechanisms of the air-surface exchange of organic pollutants and mercury in a Chinese subtropical forest Research Council of Norway Chinese Accademy of Science Norwegian Institute for Water Research L. Nizzetto, K. Borgå, T. Larssen, G. Zhang, X. Feng, K.C. Jones The players: NIVA Norwegian Institute for Water Research – Oslo State Key Lab. for Organic Geochemistry (CAS) – Guanzhou State Key Lab. for Environmental Geochemistry (CAS) - Guiyang Lancaster Environment Centre, Lancaster, United Kingdom The numbers: - 2 outstanding European research institutes - 2 outstanding Chinese research institutes - 6 senior researchers, 2 PhD students. - 3 million Norwegian Krowns (3,6 million RMB) from Norwegian Research Council - About 1,5 million (1,8 million RMB) as counter part from the involved institutes The place: Dinghushan Biosphere Reserve - Subtropical forest The methods: Top soil layer Organic matter Deposition of: - Organic matter - Rain - ”Native” pollutants + Environmental and climatic conditions PUF Sorbant for pollutants The ”big picture” Effect of Climate change on the global fate and exposure to persistent pollutants Chinese ecoregions: From tropical to boreal ecosystems Thank you for your attention!