Great Lakes atmospheric deposition

Gatz DF, Sweet CW, Basu I, Vermette SJ, Harlin K, Bauer S (1994) Great Lakes atmospheric deposition network (IADN) Data report 1990-1992. Illinois State Water Survey... 

Precipitation has not been extensively investigated as an input pathway for toxaphene to the Great lakes. An early report (W. Swain cited in Rice and Evans [4]) stated that samples collected near Lake Huron in 1980-1981 had toxaphene concentrations ranging from 7-108 ngL-1. Rice and Evans [4] reported a concentration of 9 ng L-1 in a composite sample from the southeastern shore of Lake Michigan for the same period. A Great Lakes atmospheric deposition workshop proposed a basin-wide consensus concentration of 0.2ngL-1 for the period 1989-1991 based on measurements in northwestern Ontario [69]. Elsewhere, Harder et al. [70] detected toxaphene in South Car-... 

In air, endrin is expected to be associated primarily with particulate matter, based on its low vapor pressure and high Koc (Kenaga 1980). However, small amounts of endrin in the atmosphere may exist in the vapor phase (Eisenreich et al. 1981). Because of its low solubility (200 pg/L, see Table 3-2), endrin would not be expected to be removed significantly from the atmosphere by wet deposition. Particle-adsorbed endrin will be removed from the atmosphere by both wet and dry deposition. In recent studies in the Great Lakes area, endrin was found in 5% of 450 wet deposition (rain/snow) samples collected between 1986-1991, at volume weighted mean concentrations ranging from 0.02 to 0.98 ng/L (ppt) (Chan et al. 1994). 

Arimoto R. 1989. Atmospheric deposition of chemical contaminants to the Great Lakes. Journal of Great Lakes Research 15(2) 339-356. 

Somewhat similar levels in air, between 0.5 and 5 ng/m (mean, 2 ng/m ) of di(2-ethylhexyl) phthalate have been found in the Great Lakes ecosystem (Canada and United States). The concentration of di(2-ethylhexyl) phthalate in precipitation ranged from 4 to 10 ng/L (mean, 6 ng/L). Atmospheric fluxes to the Great Lakes are a combination of dry and wet removal processes. The total deposition of di(2-ethylhexyl) phthalate into Lakes Superior, Michigan, Huron, Erie and Ontario was estimated to amount to 16, 11, 12, 5.0 and 3.7 tonnes per year, respectively (Eisenreich et al., 1981). 

Eisenreich, S. J., W. A. Willford, and W. M. J. Strachan, The role of atmospheric deposition in organic contaminant cycling in the Great Lakes . In Intermedia Pollutant Transport Modelling and Field Measurements, D. Allen, Ed., Plenum Press, New York, 1989, pp. 19-40. 

Eventually, atmospheric arsenic falls on the Earth s surface through wet and dry deposition. Sweet, Weiss and Vermette (1998) evaluated the deposition of arsenic over lakes Erie, Michigan, and Superior in the Great Lakes of North America. Overall, the wet and dry deposition rates for the lakes were very similar. Specifically, they were 72-94 and 66-91 pgm 2year 1, respectively. 

Sweet, C.W., Weiss, A. and Vermette, S.J. (1998) Atmospheric deposition of trace metals at three sites near the Great Lakes. Water Air and Soil Pollution, 103(1-4), 423-39. 

A thorough analysis of atmospheric transport and deposition to the Great Lakes has been carried out using the HYSPLIT model developed by the US National Atmospheric and Oceanic Administration (NOAA) [28,29]. An emissions inventory of PCDD/Fs for North America in 1996 was used as input to the model. Factors considered in the fate and distribution were meteorological data, vapor-particle partitioning, aerosol characteristics, reaction with hydroxyl radicals, photolysis, and dry and wet deposition. The model was generally satisfactory at estimating fluxes, except for HpCDD and OCDD, which appeared to be underestimated by about a factor of four. The model output was summarized as 2378-TeCDD toxic equivalent concentrations (TEQs) based on the WHO mammalian 2378-TeCDD toxic equivalent factors (TEFs) [30]. Since HpCDD and OCDD were estimated to contribute only 2% of TEQs, the model was considered to be valid for the purpose intended. 

The major anthropogenic sources of PCDD/F emissions to the North American atmosphere that contribute to TEQ deposition in the Great Lakes have been estimated [28,29]. The fraction of total estimated atmospheric TEQ deposition to Lake Superior in 1996 from various sources is shown in Fig. 2. 

Fig. 3 Estimate of the air emissions and distribution of atmospheric deposition of PCDD/F-derived TEQs to the Great Lakes (g TEQ year-1) from inside and outside the Great Lakes watershed, based on the NOAA HYSPLIT model. Reproduced with permission from Cohen [28,29]...

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