title: Toxaphene deposition to Lake Ontario via precipitation, 1994-1998.
abstract: Precipitation samples collected continuously at Point Petre on Lake Ontario from November 1994 through December 1998 were analyzed for total toxaphene (=sum of hexa-, hepta-, octa-, and nonachloro bornanes) and chlorobornane congeners (1997-98 only). Composite triplicate samples were collected during 4-week intervals throughoutthe 4-year study using heated wet-only samplers. These results represent the first detailed data for toxaphene in Great Lakes precipitation. Seasonal volume-weighted mean concentrations for total toxaphene in precipitation ranged from 0.25 to 1.5 ng/L. Highest concentrations were found during the four spring (March-May) periods at roughly twice the annual means. The pattern for hexathrough nona-homologues over the 4 years did not vary appreciably with average ratios (relative to hepta-) of 0.08: 1.0:1.3:0.2. The volume-weighted mean concentrations for individual chlorobornane congeners were consistent in their season pattern with maximums seen in the spring. The major chlorobornane in precipitation, B8-2229 (Parlar 44), which was present at concentrations ranging from 0.016 to 0.079 ng/L, constituted 28 and 29% of the congener sum for 1997 and 1998, respectively. Lakewide loadings of toxaphene for Lake Ontario via precipitation were estimated to be 12, 17, 12, and 13 kg/year for 1995-1998, respectively. Previous toxaphene loading estimates were calculated for the individual Great Lakes on the basis of the only concentration data available, a single precipitation estimate of 0.2 ng/L from early work in northwestern Ontario. The loading estimates in this study indicate that precipitation inputs of toxaphene are 3-4 times higher than previously reported for Lake Ontario. The 1998 estimates of Lake Ontario wet deposition flux are 50% of the estimated gas deposition flux. However, wet flux values from this study exceed the net gas-phase mass transfer of toxaphene across the air-water interface.
authors.affiliation: National Water Research Institute, Canada Centre for Inland Waters, 867 Lakeshore Rd, Burlington, Ontario, L7R 4A6, Canada. Debbie.Burniston@ec.gc.ca
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Burniston
authors.forename: William M J
authors.initials: WM
authors.lastname: Strachan
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Wilkinson
mesh_terms: D000388:Air; D000393:Air Pollutants / Q000032:analysis; D011232:Chemical Precipitation; D002713:Chlorine / Q000032:analysis; D017753:Ecosystem; D004777:Environment; D004784:Environmental Monitoring / Q000379:methods*; D015233:Models, Statistical; D009864:Ontario; D009930:Organic Chemicals / Q000032:analysis; D011891:Rain; D012621:Seasons; D013997:Time Factors; D014112:Toxaphene / Q000032:analysis*; D014867:Water; D014873:Water Pollutants; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D009930:Organic Chemicals; D014873:Water Pollutants; D014874:Water Pollutants, Chemical; D014867:Water; D002713:Chlorine; D014112:Toxaphene