Air-water distribution of the endosulfan isomers

• Published in: Journal of environmental quality Vol. 26; no. 4; pp. 1101 - 1106
• Main Authors: Rice, C.P. (Natural Resources Institute, USDA, ARS, Beltsville, MD.), Chernyak, S.M, Hapeman, C.J, Bilboulian, S
• Format: Journal Article
• Language: English
• Published: Madison, WI American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America 01.07.1997; Crop Science Society of America; American Society of Agronomy
• Subjects: AGUA; AIR; AIRE; Applied sciences; Atmospheric pollution; CHEMICOPHYSICAL PROPERTIES; EAU; ENDOSULFAN; Exact sciences and technology; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; PROPIEDADES FISICOQUIMICAS; PROPRIETE PHYSICOCHIMIQUE; WATER; Water distribution; Sulfur heterocycle; Pollution; Insecticide; Organochlorine compounds; Henry constant; Partition coefficient; Air; Aqueous solution; Mass transfer; Isomer
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq1997.00472425002600040022x

The objective of this study was to experimentally characterize the air/water partitioning of the two major isomeric forms of commercially applied endosulfan. Henry's law constants (HLCs) or air/water partitioning constants for technical endosulfan (6,7,8,9,10-hexachloro-1,4,5a,6,9,9a hexahydro-6,9-methano-2,4,3-benzo-dioxathiepin-3-oxide) and its two major isomers, endosulfan I and endosulfan II, were experimentally determined using a wetted wall column (WWC) method. The HLC values for the isomers were significantly higher than their literature HLC values. The HLCs for salt water were higher than distilled water suggesting that the salt ions reduced the solubilities of the chemicals. The HLC of endosulfan I was log linearly related to change in temperature however, no such relationship could be established for endosulfan II. When pure endosulfan II (99% endosulfan II and 1% endosulfan I) was allowed to equilibrate in the WWC apparatus, the ratio of endosulfan II to endosulfan I in the gas phase became 8:92 at 20 degrees C. These results suggested that the II form of endosulfan was converting to the I form. This apparent conversion was observed to be temperature dependent. Air/water transfer of the endosulfan isomers was similar when either N or air was used as the gas phase. The ratio of endosulfan I to endosulfan II observed in the gas phase when HLC experiments with technical endosulfan were performed (91:9) were similar to ratios of the two isomers that are observed in field-collected air samples