Determination of Henry's law constants of organochlorine pesticides in deionized and saline water as a function of temperature

• Published in: Atmospheric environment (1994) 2006-08, Vol.40 (24), p.4538-4546
• Main Authors: Cetin, Banu, Ozer, Serdar, Sofuoglu, Aysun, Odabasi, Mustafa
• Format: Article
• Language: English
• Subjects: Applied sciences; Atmospheric pollution; Exact sciences and technology; Gas-stripping technique; Henry's law constant; Organochlorine pesticides; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Salting-out effect
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2006.04.009

The Henry's law constant ( H) is an important parameter that is required to estimate the air–water exchange of semi-volatile organic compounds. Henry's law constants for 17 banned/restricted/currently used organochlorine pesticides (OCPs) were experimentally determined using a gas-stripping technique in deionized and saline water (3%) over a temperature range of 5–35 °C. H values (at 25 °C) ranged between 0.066±0.037 Pa m 3 mol −1 (endosulfan II) and 62.0±24.2 Pa m 3 mol −1 (heptachlor) in deionized water while the range in saline water was 0.28±0.03 Pa m 3 mol −1 ( γ-HCH) and 135.2±31.3 Pa m 3 mol −1 (heptachlor). The increase in dimensionless Henry's law constants ( H′) for OCPs over the studied temperature range was between 3 ( γ-HCH)-19 times (chlorpyrifos) and 3 (endosulfan II)-80 times ( trans-nonachlor) in deionized and saline water, respectively. The calculated enthalpies of phase change (Δ H H) were within the ranges previously reported for OCPs and other organic compounds (23.8–100.2 kJ mol −1). The salting-out constant, k s, ranged between 0.04 ( γ-HCH) and 1.80 L mol −1 (endosulfan II) indicating the importance of assessing the H values of OCPs in saline water to accurately determine their partitioning and fate in seawater.