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- Bidleman, Terry Frank, et al.
(författare)
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Chiral Chemicals as Tracers of Atmospheric Sources and Fate Processes in a World of Changing Climate
- 2013
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Ingår i: Mass Spectrometry. - 2186-5116. ; 2:19, Special Issue: Proceedings of 19th International Mass Spectrometry Conference, s. S0019-
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Tidskriftsartikel (refereegranskat)abstract
- Elimination of persistent organic pollutants (POPs) under national and international regulations reduces “primary” emissions, but “secondary” emissions continue from residues deposited in soil, water, ice and vegetation during former years of usage. In a future, secondary source controlled world, POPs will follow the carbon cycle and biogeochemical processes will determine their transport, accumulation and fate. Climate change is likely to affect mobilisation of POPs through e.g., increased temperature, altered precipitation and wind patterns, flooding, loss of ice cover in polar regions, melting glaciers, and changes in soil and water microbiology which affect degradation and transformation. Chiral compounds offer advantages for following transport and fate pathways because of their ability to distinguish racemic (newly released or protected from microbial attack) and nonracemic (microbially degraded) sources. This paper discusses the rationale for this approach and suggests applications where chiral POPs could aid investigation of climate-mediated exchange and degradation processes. Multiyear measurements of two chiral POPs, trans-chlordane and α-HCH, at a Canadian Arctic air monitoring station show enantiomer compositions which cycle seasonally, suggesting varying source contributions which may be under climatic control. Large-scale shifts in the enantioselective metabolism of chiral POPs in soil and water might influence the enantiomer composition of atmospheric residues, and it would be advantageous to include enantiospecific analysis in POPs monitoring programs.
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| 2. |
- Kurt-Karakus, Perihan Binnur, et al.
(författare)
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CURRENT-USE PESTICIDES IN INLAND LAKE WATERS, PRECIPITATION, AND AIR FROM ONTARIO, CANADA
- 2011
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Ingår i: Environmental Toxicology and Chemistry. - : WILEY-BLACKWELL. - 0730-7268 .- 1552-8618. ; 30:7, s. 1539-1548
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Tidskriftsartikel (refereegranskat)abstract
- Concentrations of current-use pesticides (CUPs) in water, zooplankton, precipitation, and air samples as well as stereoisomer fractions (SF; herbicidally active/total stereoisomers) of metolachlor were determined in water samples collected from 10 remote inland lakes in Ontario, Canada, between 2003 and 2005. The most frequently detected chemicals in lake water, precipitation, and air were alpha-endosulfan, atrazine, metolachlor, chlorpyrifos, chlorothalonil, and trifluralin, and alpha-endosulfan and chlorpyrifos were the chemicals detected frequently in zooplankton. Air concentrations of these CUPs were within the range of previously reported values for background sites in the Great Lakes basin. High detection frequency of CUPs in lake water and precipitation was attributed to high usage amounts, but some CUPs such as ametryn and disulfoton that were not used in Ontario were also detected. Mean bioaccumulation factors (wet wt) in zooplankton for endosulfan ranged from 160 to 590 and from 20 to 60 for chlorpyrifos. The overall median SF of metolachlor in precipitation samples (0.846) was similar to that of the commercial S-metolaehlor (0.882). However, the median SF of metolachlor in water from all sampled inland lakes (0.806) was significantly lower compared with Ontario rivers (0.873) but higher compared with previous measurements in the Great Lakes (0.710). Lakes with smaller watershed areas showed higher SFs, supporting the hypothesis of stereoselective processing of deposited metolachlor within the watersheds, followed by transport to the lakes. Environ. Toxicol. Chem. 2011;30:1539-1548. (C) 2011 SETAC
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