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1G - Long-range transport of pollutants (chemicals) (WEP/5) Lindane Volatilisation From Canola Fields - Ambient Air Measurements Versus Flux Chambers. Waite, Don1, Sproull, Jim2, Quiring, Dwight1, Chau, Diana2, Cabalo, Edna2, Snihura, Adrian3, 1 Environment Canada, Regina, SK, Canada2 Environment Canada, Edmonton, AB, Canada3 Canadian ORTECH Environmental, Toronto, ON, Canada ABSTRACT- The insecticide lindane (gamma-hexachlorocyclohexane) is used primarily, in Canada, in treatments for canola ( Brassica napus) seed. It has been shown that lindane so applied will volatilise with 12-30 % entering the atmosphere within six weeks after the seed is planted. Both high volume air samplers and flux chambers were used to measure lindane volatilisation from a canola field and the results from each method compared. Daily samples were collected from the three flux chambers located on the field and volatilisation rates varied between them. Lindane was found in the air of the chambers on the first day after planting. Volatilisation rates were low for the first 7 d but rapidly increased during the second week. This was consistent with previous studies. Weekly composite air samples, from three heights above the canola field, were used to calculate volatilisation rates from the field. These were 190 mg ha-1 week-1(week 1) and 420 mg ha-1 week-1 (second week). Weekly volatilisation rates calculated from the flux chamber measurements were 40.0 mg ha-1 week-1 (week 1) and 143.8 mg ha-1 week-1 (second week). Volatilisation rates measured with the flux chambers were, then, somewhat lower than those made using ambient air samples. This paper will describe the sampling techniques and compare data the derived from the two methods. Key words: volatilisation, lindane, flux chambers, atmospheric |
