Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Changing sources and environmental factors reduce the rates of decline of organochlorine pesticides in the Arctic atmosphere
AU - Becker, Sara
AU - Halsall, Crispin
AU - Tych, Wlodzimierz
AU - Kallenborn, R.
AU - Schlabach, M.
AU - Mano, Stein
PY - 2012
Y1 - 2012
N2 - An extensive database of organochlorine (OC) pesticide concentrations measured at the Norwegian Arctic monitoring station at Ny-Alesund, Svalbard, was analysed to assess longer-term trends in the Arctic atmosphere. Dynamic Harmonic Regression (DHR) is employed to investigate the seasonal and cyclical behaviour of chlordanes, DDTs and hexachlorobenzene (HCB), and to isolate underlying interannual trends. Although a simple comparison of annual mean concentrations (1994–2005) suggest a decline for all of the OCs investigated, the longer-term trends identified by DHR only show a significant decline for p,p0-DDT. Indeed, HCB shows an increase from 2003–2005. This is thought to be due to changes in source types and the presence of impurities in current use pesticides, together with retreating sea ice affecting air-water exchange. Changes in source types were revealed by using isomeric ratios for the chlordanes and DDTs. Declining trends in ratios of trans-chlordane/cischlordane (TC/CC) indicate a shift from primary sources, to more “weathered” secondary sources, whereas an increasing trend in o,p-DDT/p,p-DDT ratios indicate a shift from use of technical DDT to dicofol. Continued monitoring of these OC pesticides is required to fully understand the influence of a changing climate on the behaviour and environmental cycling of these chemicals in the Arctic as well as possible impacts from “new” sources.
AB - An extensive database of organochlorine (OC) pesticide concentrations measured at the Norwegian Arctic monitoring station at Ny-Alesund, Svalbard, was analysed to assess longer-term trends in the Arctic atmosphere. Dynamic Harmonic Regression (DHR) is employed to investigate the seasonal and cyclical behaviour of chlordanes, DDTs and hexachlorobenzene (HCB), and to isolate underlying interannual trends. Although a simple comparison of annual mean concentrations (1994–2005) suggest a decline for all of the OCs investigated, the longer-term trends identified by DHR only show a significant decline for p,p0-DDT. Indeed, HCB shows an increase from 2003–2005. This is thought to be due to changes in source types and the presence of impurities in current use pesticides, together with retreating sea ice affecting air-water exchange. Changes in source types were revealed by using isomeric ratios for the chlordanes and DDTs. Declining trends in ratios of trans-chlordane/cischlordane (TC/CC) indicate a shift from primary sources, to more “weathered” secondary sources, whereas an increasing trend in o,p-DDT/p,p-DDT ratios indicate a shift from use of technical DDT to dicofol. Continued monitoring of these OC pesticides is required to fully understand the influence of a changing climate on the behaviour and environmental cycling of these chemicals in the Arctic as well as possible impacts from “new” sources.
UR - http://www.scopus.com/inward/record.url?scp=84860713350&partnerID=8YFLogxK
U2 - 10.5194/acp-12-4033-2012
DO - 10.5194/acp-12-4033-2012
M3 - Journal article
AN - SCOPUS:84860713350
VL - 12
SP - 4033
EP - 4044
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
SN - 1680-7316
IS - n/a
ER -