Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Atmospheric PCBs and organochlorine pesticides in Birmingham, UK: concentrations, sources, temporal and seasonal trends
AbstractConcentrations of individual PCBs and DDT, DDE, α- and γ-HCH were recorded in 62 air samples of 24h duration taken every 1–2 weeks at an urban location in Birmingham, UK between April 1999 and July 2000. Concentrations of PCBs 31/28, 52, 49, 47, 105, 149, 153, 138/164, 174, and 180 were significantly lower (p<0.05) than those recorded at the same site in 1997–1998. While DDT concentrations and DDT:DDE ratios were much lower than those recorded in southern England in 1992–1993; no such decline was observed in concentrations of α- and γ-HCH, or the α:γ-HCH ratio. These data are consistent with declining European usage of DDT, but continuing UK use of γ-HCH, and overseas use and subsequent atmospheric transport of “technical” HCH. γ-HCH concentrations displayed two non-temperature dependent peaks in spring and late summer/early autumn, consistent with agricultural use patterns. Multiple linear regression analysis was used to elucidate the relative influence of temperature, wind direction and a variety of other meteorological variables on atmospheric concentrations of PCBs. When all samples were considered, concentrations of most PCB congeners were influenced by a combination of reciprocal temperature, wind direction, and wind speed. Plotting the ratio of the Beta weightings for the regression coefficients for reciprocal temperature and sine (or cosine) of wind direction against chlorine number, revealed a general increase in the relative influence of temperature compared to wind direction with increasing chlorine number. However, when the 31 samples for which the wind speed <4.4ms−1 were analysed; only temperature and atmospheric relative humidity were influential for most congeners. This absence of influence of wind direction under relatively calm atmospheric conditions, suggests that it is medium-to-long range transport rather than local sources that exerts the greatest influence on PCB concentrations at our site.
Atmospheric PCBs and organochlorine pesticides in Birmingham, UK: concentrations, sources, temporal and seasonal trends
AbstractConcentrations of individual PCBs and DDT, DDE, α- and γ-HCH were recorded in 62 air samples of 24h duration taken every 1–2 weeks at an urban location in Birmingham, UK between April 1999 and July 2000. Concentrations of PCBs 31/28, 52, 49, 47, 105, 149, 153, 138/164, 174, and 180 were significantly lower (p<0.05) than those recorded at the same site in 1997–1998. While DDT concentrations and DDT:DDE ratios were much lower than those recorded in southern England in 1992–1993; no such decline was observed in concentrations of α- and γ-HCH, or the α:γ-HCH ratio. These data are consistent with declining European usage of DDT, but continuing UK use of γ-HCH, and overseas use and subsequent atmospheric transport of “technical” HCH. γ-HCH concentrations displayed two non-temperature dependent peaks in spring and late summer/early autumn, consistent with agricultural use patterns. Multiple linear regression analysis was used to elucidate the relative influence of temperature, wind direction and a variety of other meteorological variables on atmospheric concentrations of PCBs. When all samples were considered, concentrations of most PCB congeners were influenced by a combination of reciprocal temperature, wind direction, and wind speed. Plotting the ratio of the Beta weightings for the regression coefficients for reciprocal temperature and sine (or cosine) of wind direction against chlorine number, revealed a general increase in the relative influence of temperature compared to wind direction with increasing chlorine number. However, when the 31 samples for which the wind speed <4.4ms−1 were analysed; only temperature and atmospheric relative humidity were influential for most congeners. This absence of influence of wind direction under relatively calm atmospheric conditions, suggests that it is medium-to-long range transport rather than local sources that exerts the greatest influence on PCB concentrations at our site.
Atmospheric PCBs and organochlorine pesticides in Birmingham, UK: concentrations, sources, temporal and seasonal trends
Harrad, Stuart (Autor:in) / Mao, Hongjun (Autor:in)
Atmospheric Environment ; 38 ; 1437-1445
01.12.2003
9 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch