Liisa M Jantunen

Environment Canada, Montréal, Quebec, Canada

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Publications (73)215.67 Total impact

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    ABSTRACT: The arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993-2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs, toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF) and trifluralin (TFN). Pentachloronitrobenzene (PCNB, quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT and TFN) or showed no significant change (CPF, DAC), while most compounds declined in air. Chlordane compound fractions TC/(TC+CC) and TC/(TC+CC+TN) decreased in water and air, while CC/(TC+CC+TN) and TN/(TC+CC+TN) increased, suggesting selective removal of more labile TC over time and/or a shift in chlordane sources. Water/air fugacity ratios indicated net volatilization (FR >1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs, but net deposition (FR <1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure, evaluate the effectiveness of International Protocols and provides insights for the environmental fate of new and emerging chemicals.
    Environmental Science & Technology 07/2015; DOI:10.1021/acs.est.5b01303 · 5.48 Impact Factor
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    ABSTRACT: RATIONALEThe manufacturing and uses of hexachlorocyclohexane (HCH) have resulted in a serious environmental challenge and legacy. This study highlights the ability of compound specific isotope analysis (CSIA) to distinguish among various HCH sources and to support the evaluation of the potential for in situ biodegradation in contaminated groundwater.METHODS Tests were conducted to verify the absence of significant isotope fractionation during HCH sample pre-concentration including dichloromethane extraction, solvent exchange into iso-octane, and H2SO4 clean-up, and analysis by gas chromatography/combustion-isotope ratio mass spectrometry (GC/C-IRMS). The method was then applied to four Technical Grade (TG) HCH mixtures procured from different sources and to groundwater samples from a contaminated site.RESULTSThe pre-concentration method enabled determination of carbon isotope ratios (δ13C values) of HCH isomers with no significant isotopic fractionation. The TG-HCH mixtures had significantly different δ13C values. Moreover, for any given TG-HCH, all isomers had δ13C values within 1.1‰ of each other – a distinctly uniform fingerprint. At the HCH-contaminated field site, compared with source wells, downgradient wells showed significant (up to 5.1‰) enrichment in 13C and the δ13C values of the HCH isomers were significantly different from each other.CONCLUSIONSA method was successfully developed for the CSIA of HCH isomers that showed potential for HCH source differentiation and identification of HCH in situ biodegradation. At the HCH-contaminated site, the observed preferential isotopic enrichment of certain isomers relative to others for a given source allows differentiation between biodegraded and non-biodegraded HCH. Copyright © 2015 John Wiley & Sons, Ltd.
    Rapid Communications in Mass Spectrometry 03/2015; 29(6). DOI:10.1002/rcm.7146 · 2.64 Impact Factor
  • T. F. Bidleman · L. M. Jantunen · H. Hung · J. Ma · G. A. Stern · B. Rosenberg · J. Racine
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    ABSTRACT: Air samples collected during 1994-2000 at the Canadian Arctic air monitoring station Alert (82 degrees 30'N, 62 degrees 20'W) were analysed by enantiospecific gas chromatography-mass spectrometry for alpha-hexachlorocyclohexane (alpha-HCH), trans-chlordane (TC) and cis-chlordane (CC). Results were expressed as enantiomer fractions (EF = peak areas of (+)/[(+) + (-)] enantiomers), where EFs = 0.5, <0.5 and >0.5 indicate racemic composition, and preferential depletion of (+) and (-) enantiomers, respectively. Long-term average EFs were close to racemic values for alpha-HCH (0.504 +/- 0.004, n = 197) and CC (0.505 +/- 0.004, n = 162), and deviated farther from racemic for TC (0.470 +/- 0.013, n = 165). Digital filtration analysis revealed annual cycles of lower alpha-HCH EFs in summer-fall and higher EFs in winter-spring. These cycles suggest volatilization of partially degraded alpha-HCH with EF < 0.5 from open water and advection to Alert during the warm season, and background transport of alpha-HCH with EF > 0.5 during the cold season. The contribution of sea-volatilized alpha-HCH was only 11% at Alert, vs. 32% at Resolute Bay (74.68 degrees N, 94.90 degrees W) in 1999. EFs of TC also followed annual cycles of lower and higher values in the warm and cold seasons. These were in phase with low and high cycles of the TC / CC ratio (expressed as F-TC = TC/(TC + CC)), which suggests greater contribution of microbially "weathered" TC in summer-fall versus winter-spring. CC was closer to racemic than TC and displayed seasonal cycles only in 1997-1998. EF profiles are likely to change with rising contribution of secondary emission sources, weathering of residues in the environment, and loss of ice cover in the Arctic. Enantiomer-specific analysis could provide added forensic capability to air monitoring programs.
    Atmospheric Chemistry and Physics 02/2015; 15(3):1411-1420. DOI:10.5194/acp-15-1411-2015 · 5.51 Impact Factor
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    ABSTRACT: For decades sea ice has been perceived as a physical barrier for the loading of contaminants to the Arctic Ocean. We show that sea ice, in fact, facilitates the delivery of organic contaminants to the Arctic marine food web through processes that: 1) are independent of contaminant physical-chemical properties (e.g. 2-3-fold increase in exposure to brine-associated biota), and 2) depend on physical-chemical properties and, therefore, differentiate between contaminants (e.g. atmospheric loading of contaminants to melt ponds over the summer, and their subsequent leakage to the ocean). We estimate the concentrations of legacy organochlorine pesticides (OCPs) and current-use pesticides (CUPS) in melt pond water in the Beaufort Sea, Canadian High Arctic, in 2008, at near-gas exchange equilibrium based on Henry's law constants (HLCs), air concentrations and exchange dynamics. CUPs currently present the highest risk of increased exposures through melt pond loading and drainage due to the high ratio of melt pond water to seawater concentration (Melt pond Enrichment Factor, MEF), which ranges from 2 for dacthal to 10 for endosulfan I. Melt pond contaminant enrichment can be perceived as a hypothetical 'pump' delivering contaminants from the atmosphere to the ocean under ice-covered conditions, with 2-10% of CUPs annually entering the Beaufort Sea via this input route compared to the standing stock in the Polar Mixed Layer of the ocean. The abovementioned processes are strongly favored in first-year ice compared to multi-year ice and, therefore, the dynamic balance between contaminant inventories and contaminant deposition to the surface ocean is being widely affected by the large-scale icescape transition taking place in the Arctic.
    Science of The Total Environment 01/2015; 506-507:444. DOI:10.1016/j.scitotenv.2014.11.040 · 4.10 Impact Factor
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    Mahiba Shoeib · Lutz Ahrens · Liisa Jantunen · Tom Harner
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    ABSTRACT: Concentrations of organobromine (BFRs), organochlorine (CFRs) and organophosphate esters flame retardants and plasticizers (PFRs) in air were monitored for over one year at an urban site in Toronto, Canada during 2010–2011. The mean value for polybrominated diphenyl ethers (BDEs) (gas + particle phase) was 38 pg/m3 with BDE-47 and BDE-99 as the dominant congeners. The mean concentrations in air for ∑non-BDE (BFRs and CFRs), was 9.6 pg/m3 – about four times lower than the BDEs. The brominated FRs: TBP-AE, BTBPE, EH-TBB, BEH-TEBP and the chlorinated syn- and anti-DP were detected frequently, ranging from 87% to 96%. Highest concentrations in air among all flame retardant classes were observed for the Σ-PFRs. The yearly mean concentration in air for ΣPFRs was 2643 pg/m3 with detection frequency higher than 80%. Except for TBP-AE and b- DBE-DBCH, non-BDEs (BFRs, CFRs and PFRs) were mainly associated with the particle phase. BDE concentrations in air were positively correlated with temperature indicating that volatilization from local sources was an important factor controlling levels in air. This correlation did not hold for most BFRs, CFRs and PFRs which were mainly on particles. For these compounds, air concentrations in Toronto are likely related to emissions from point sources and advective inputs. This study highlights the importance of urban air monitoring for FRs. Urban air can be considered a sentinel for detecting changes in the use and application of FRs in commercial products.
    Atmospheric Environment 12/2014; 99:140–147. DOI:10.1016/j.atmosenv.2014.09.040 · 3.28 Impact Factor
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    Dioxin 2014; 09/2014
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    ABSTRACT: Organophosphate compounds are ubiquitous in the environment and to better understand and predict their environmental transport and fate, well-defined physical-chemical properties are needed. The subcooled liquid-phase vapor pressures at 298.15 K (p298) were determined for 11 chlorinated and nonchlorinated phosphate flame retardants (PFRs) by the capillary gas chromatography retention time method (GC-RT). Values of log (p298/Pa) ranged from −5.22 to −1.32 and enthalpies of vaporization (ΔlgH/kJ·mol–1) ranged from 82.0 to 109. Log (p298/Pa) by GC-RT showed good overall agreement with estimates using the Modified Grain Method (EpiSuite) and with the mean of experimental and in silico literature values, whereas values for the chlorinated PFRs appeared to be overestimated. SPARC modeling seriously underestimated p298, especially for the less volatile compounds. The Junge–Pankow adsorption model at 288.15 K predicted that most of the PFRs would be predominantly in the particulate phase in urban air and distributed between the particulate and gaseous phases in background air.
    Journal of Chemical & Engineering Data 04/2014; 59(5):1441–1447. DOI:10.1021/je401026a · 2.05 Impact Factor
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    ABSTRACT: Heterogeneous reactions between OH radicals and emerging flame retardant compounds coated on inert particles have been investigated. Organophosphate esters (OPEs) including tri-phenyl phosphate (TPhP), tris-2-ethylhexyl phosphate (TEHP) and tris-1,3-dichloro-2-propyl phosphate (TDCPP) were coated on (NH4)2SO4 particles and exposed to OH radicals in a photo-chemical flow tube at 298 K and (38.0±2.0) % RH. The degradation of these particle-bound OPEs was observed as a result of OH exposure, as measured using a Time-of-Flight Aerosol Mass Spectrometer. The derived second-order rate constants (k2) for the heterogeneous loss of TPhP, TEHP and TDCPP were (2.1±0.19)×10-12, (2.7±0.63)×10-12 and (9.2±0.92)×10-13 cm3 molecule-1 s-1, respectively, from which approximate atmospheric lifetimes are estimated to be 5.6 (5.2-6.0), 4.3 (3.5-5.6), and 13 (11-14) days. Additional coating of the OPE coated particles with an OH radical active species further increased the lifetimes of these OPEs. These results represent the first reported estimates of heterogeneous reaction rate constants for these species. The results demonstrate that particle bound OPEs are highly persistent in the atmosphere with regard to OH radical oxidation, consistent with the assumption that OPEs can undergo medium or long-range transport, as previously proposed on the basis of field measurements. Finally, these results indicate that future risk assessment and transport modeling of emerging priority chemicals with semi to low-volatility must consider particle phase heterogeneous loss processes when evaluating environmental persistence.
    Environmental Science & Technology 01/2014; 48:1041-1048. DOI:10.1021/es404515k · 5.48 Impact Factor
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    ABSTRACT: Loadings from Toronto, Canada to Lake Ontario were quantified and major sources and pathways were identified, with the goal of informing opportunities for loading reductions. The contaminants were polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers, (PBDEs), polycyclic aromatic hydrocarbons (PAHs) and polycyclic musks (PCMs). Loadings were calculated from measured concentrations for three major pathways: atmospheric processes, tributary runoff, and wastewater treatment plant (WWTP) effluents. Although atmospheric deposition to the Great Lakes has received the greatest attention, this was the dominant loading pathway for PCBs only (17±5.3 kg/y or 66% of total loadings). PCB loadings reflected elevated urban PCB air concentrations due to, predominantly, primary emissions. These loadings contribute to consumption advisories for nearshore fish. PBDE loadings to the lake, again from mainly primary emissions, were 48% (9.1±1.3 kg/y) and 42% (8.0±5.7 kg/y) via tributaries and WWTPs, respectively, consistent with emissions deposited and subsequently washed-off of urban surfaces and emissions to the sewage system. PAHs loadings of 1600±280 kg/y (71%) from tributaries were strongly associated with vehicle transportation and impervious surfaces. PCM loadings were 83% (±140 kg/y) from WWTP final effluent, reflecting their use in personal care products. Opportunities for source reduction lie in reducing the current inventories of in-use PCBs and PBDE-containing products, reducing vehicle emissions of PAHs and use of PAHs in the transportation network (e.g., pavement sealants), and improving waste water treatment technology.
    Environmental Science and Technology 01/2014; DOI:10.1021/es403209z · 5.48 Impact Factor
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    ABSTRACT: Archived specimens of the scavenging amphipod Eurythenes gryllus, collected from 2075-4250 m below the surface on five expeditions to the western and central Arctic Ocean between 1983-1998, were analyzed for total mercury (sum-Hg), methyl mercury (MeHg), polychlorinated biphenyls (PCBs) and other industrial or byproduct organochlorines (chlorobenzenes, pentachloroanisole, octachlorostyrene), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). Median sum-Hg concentrations ranged from 70 to 366 ng g-1 wet weight (ww). MeHg concentrations (3.55 to 23.5 ng g-1 ww) accounted for 1.7 to 20.1% (median 3.7%) of sum-Hg. Sum-Hg and MeHg were positively and significantly correlated with ww (sum-Hg r2 = 0.18, p = 0.0004, n=63; MeHg r2 = 0.42, p = 0.0004, n=25), but not significantly with δ13C nor δ15N. Median concentrations of total persistent organic pollutants (POPs) ranged from 9750-156000 ng g-1 lipid weight, with order of abundance: sum-TOX (chlorobornanes quantified as technical toxaphene) > sum-PCBs > sum-DDTs > sum-chlordanes > sum-mirex compounds > sum-PBDEs ~ sum-chlorobenzenes ~ octachlorostyrene > alpha-hexachlorocyclohexane ~ hexachlorobenzene ~ pentachloroanisole. Enantioselective accumulation was found for the chiral OCPs o,p'-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane. Lipid-normalized POPs concentrations were elevated in amphipods with lipid percentages ≤10%, suggesting that utilization of lipids resulted in concentration of POPs in the remaining lipid pool. Multidimensional Scaling (MDS) analysis using log-transformed physiological variables and lipid-normalized organochlorine concentrations distinguished amphipods from the central vs. western arctic stations. This distinction was also seen for PCB homologs, while profiles of other compound classes were more related to specific stations rather than central-west differences.
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    ABSTRACT: Archived specimens of the scavenging amphipod Eurythenes gryllus, collected from 2075 to 4250 m below the surface on five expeditions to the western and central Arctic Ocean between 1983 and 1998, were analyzed for total mercury (ΣHg), methyl mercury (MeHg), polychlorinated biphenyls(PCBs) and other industrial or byproduct organochlorines (chlorobenzenes, pentachloroanisole, octachlorostyrene), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). Median ΣHg concentrations ranged from 70 to 366 ng g−1 wet weight (ww). MeHg concentrations (3.55 to 23.5 ng g−1 ww) accounted for 1.7 to 20.1% (median 3.7%) of ΣHg. ΣHg and MeHg were positively and significantly correlated with ww (ΣHg r2 = 0.18, p = 0.0004, n = 63; MeHg r2 = 0.42, p = 0.0004, n = 25), but not significantly with δ13C nor δ15N. Median concentrations of total persistent organic pollutants (POPs) ranged from 9750 to 156 000 ng g−1 lipid weight, with order of abundance: ΣTOX (chlorobornanes quantified as technical toxaphene) > ΣPCBs > ΣDDTs > Σchlordanes > Σmirex compounds > ΣBDEs ∼ Σchlorobenzenes ∼ octachlorostyrene > α-hexachlorocyclohexane ∼ hexachlorobenzene ∼ pentachloroanisole. Enantioselective accumulation was found for the chiral OCPs o,p′-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane. Lipid-normalized POPs concentrations were elevated in amphipods with lipid percentages ≤10%, suggesting that utilization of lipids resulted in concentration of POPs in the remaining lipid pool. Multidimensional Scaling (MDS) analysis using log-transformed physiological variables and lipidnormalized organochlorine concentrations distinguished amphipods from the central vs western arctic stations. This distinctionwas also seen for PCB homologues, whereas profiles of other compound classes were more related to specific stations rather than central-west differences.
    Environmental Science & Technology 01/2013; 47:5553-5561. · 5.48 Impact Factor
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    Canadian Arctic Contaminants Assessment Report On Persistent Organic Pollutants, Edited by P. Kurt-Karakus, J. Stow, D.C.G. Muir, 01/2013: chapter 2: pages 19-146; Aboriginal Affairs and Northern Development Canada.
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    ABSTRACT: Archived specimens of the scavenging amphipod Eurythenes gryllus, collected from 2075 to 4250 m below the surface on five expeditions to the western and central Arctic Ocean between 1983 and 1998, were analyzed for total mercury (ΣHg), methyl mercury (MeHg), polychlorinated biphenyls (PCBs) and other industrial or byproduct organochlorines (chlorobenzenes, pentachloroanisole, octachlorostyrene), rganochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). Median ΣHg concentrations ranged from 70 to 366 ng g−1 wet weight (ww). MeHg concentrations (3.55 to 23.5 ng g−1 ww) accounted for 1.7 to 20.1% (median 3.7%) of ΣHg. ΣHg and MeHg were positively and significantly correlated with ww (ΣHg2 = 0.18, p = 0.0004, n = 63; MeHg r2 = 0.42, p = 0.0004, n = 25), but not significantly with δ13C nor 15N. Median concentrations of total persistent organic pollutants (POPs) ranged from 9750 to 156 000 ng g−1 lipid weight, with order of abundance: ΣTOX (chlorobornanes quantified as technical toxaphene) > ΣPCBs > ΣDDTs > Σchlordanes > Σmirex compounds > ΣBDEs ∼ Σchlorobenzenes ∼ octachlorostyrene > α-hexachlorocyclohexane ∼ hexachlorobenzene ∼ pentachloroanisole. Enantioselective accumulation was found for the chiral OCPs o,p′-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane. Lipid-normalized POPs concentrations were elevated in amphipods with lipid percentages ≤10%, suggesting that utilization of lipids resulted in concentration of POPs in the remaining lipid pool. Multidimensional Scaling (MDS) analysis using log-transformed physiological variables and lipidnormalized organochlorine concentrations distinguished amphipods from the central vs western arctic stations. This distinction was also seen for PCB homologues, whereas profiles of other compound classes were more related to specific stations rather than central-west differences.
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    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.
    01/2013; 2(Spec Iss):S0019. DOI:10.5702/massspectrometry.S0019
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    ABSTRACT: Elimination of persistent organic pollutants (POPs) under national and international controls reduces “primary” emissions, but “secondary” emissions continue from residues deposited in soil, water, ice and vegetation during former years of high usage. Secondary sources are expected to dominate in the future, when POPs transport and accumulation will be controlled by air–surface exchange and the biogeochemical cycle of organic carbon. Climate change is likely to affect mobilization of POPs through, e.g., increased temperature, 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 altered) sources. Here we explain the rationale for this approach and suggest applications where chiral POPs could aid investigation of climate–mediated exchange and degradation processes. Examples include distinguishing agricultural vs. non–agricultural and recently used vs. residual pesticides, degradation and sequestration processes in soil, historical vs. recent atmospheric deposition, sources in arctic air and influence of ice cover on volatilization.
    Atmospheric Pollution Research 10/2012; 3(4):371-382. DOI:10.5094/APR.2012.043 · 1.23 Impact Factor
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    ABSTRACT: The air-sea gas exchange of alpha-hexachlorocyclohexane (α-HCH) in the Canadian Arctic was estimated using a micrometeorological approach and the commonly used Whitman two-film model. Concurrent shipboard measurements of α-HCH in air at two heights (1 and 15 m) and in surface seawater were conducted during the Circumpolar Flaw Lead study in 2008. Sampling was carried out during eight events in the early summer time when open water was encountered. The micrometeorological technique employed the vertical gradient in air concentration and the wind speed to estimate the flux; results were corrected for atmospheric stability using the Monin-Obukhov stability parameter. The Whitman two-film model used the concentrations of α-HCH in surface seawater, in bulk air at 1 and 15 m above the surface, and the Henry's law constant adjusted for temperature and salinity to derive the flux. Both approaches showed that the overall net flux of α-HCH was from water to air. Mean fluxes calculated using the micrometeorological technique ranged from -3.5 to 18 ng m(-2) day(-1) (mean 7.4), compared to 3.5 to 14 ng m(-2) day(-1) (mean 7.5) using the Whitman two-film model. Flux estimates for individual events agreed in direction and within a factor of two in magnitude for six of eight events. For two events, fluxes estimated by micrometeorology were zero or negative, while fluxes estimated with the two-film model were positive, and the reasons for these discrepancies are unclear. Improvements are needed to shorten air sampling times to ensure that stationarity of meteorological conditions is not compromised over the measurement periods. The micrometeorological technique could be particularly useful to estimate fluxes of organic chemicals over water in situations where no water samples are available.
    Environmental Science and Pollution Research 07/2012; 19(6):1908-14. DOI:10.1007/s11356-012-0955-4 · 2.76 Impact Factor
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    ABSTRACT: Studies on residues of currently and never used organochlorine pesticides (OCPs) facilitate the assessment of the contamination level, distribution, sources, transportation, and trend of these selected OCPs in China. In this work we investigated the concentration levels of endosulfans and chlordane, which are currently used, and the never used aldrin and dieldrin in the province of Zhejiang, a rainy, and hilly tea-growing province in eastern China. The average/mean residue levels of OCPs was in the order ∑endosulfan > ∑chlordane > aldrin > dieldrin. The residue level was in good agreement with the usage of OCPs in Zhejiang. The spatial distribution showed that the residues of OCPs in soils from the mountain area were always higher than those in soils from the plains. The distribution characteristics were related to usage for current-use OCPs and temperature for never used OCPs. The isomeric ratios and enantiomeric fractions are useful tools to identify the degradation preference of contaminants. The wide range of ratios between trans-chlordane (TC) and cis-chlordane (CC) indicated that the degradation of the two isomers of chlordane was different at different sites. Nonracemic residues of TC and CC were observed in most soils; this is significant since the enantiomers have different toxicities.
    Journal of Agricultural and Food Chemistry 03/2012; 60(12):2982-8. DOI:10.1021/jf204921x · 3.11 Impact Factor