Effect of the diffusivity on the transport and fate of pesticides in water
- 72 Downloads
Diffusion coefficients of six common pesticides—cyromazine, chlorotoluron, pirimicarb, metazachlor, tebuconazole and sulcotrione—in water were measured as a function of temperature from 5 to 50 °C using the Taylor dispersion technique. At room temperature (25 °C), the lower diffusivity, 0.35 × 10−9 m2 s−1, is obtained for tebuconazole. For the other studied pesticides, diffusivities are higher, varying at 25 °C from 0.59 × 10−9 m2 s−1 for pirimicarb to 0.73 × 10−9 m2 s−1 for cyromazine. A group contribution method was developed to estimate diffusion coefficients of a larger number of pesticides, leading to a precision of 15%. Diffusion coefficients were then incorporated in a prediction scheme of the fate of persistent pollutants in the environment (fugacity soil model). The precision obtained with the group contribution model was proved to be sufficient for use in this environmental model. The introduction in such a model of an experimental or estimated value for the diffusion coefficient thus different for each pesticide is an improvement compared to the use of a constant value as often proposed in the literature.
KeywordsDiffusivity Pesticides Group contribution method Environmental fate Fugacity model
The authors thank the Regional Auvergne Council, CNRS, the French Ministry of Higher Education and Research and the European Regional Development Fund for financial support to buy the diffusion coefficient equipment. The authors acknowledge Philippe Bouchard for giving tebuconazole samples.
- Ali I, Jain CK (1998) Groundwater contamination and health hazards by some of the most commonly used pesticides. Curr Sci 75:1011–1014Google Scholar
- Ali I, Singh P, Rawat MSM, Badoni A (2008) Analysis of organochlorine pesticides in the Hindon river water, India. J Environ Prot Sci 2:47–53Google Scholar
- Baum EJ (1998) Chemical property estimation: theory and application. Lewis Publishers, Boca RatonGoogle Scholar
- Cussler EL (1997) Diffusion mass transfer in fluids systems. Cambridge University Press, CambridgeGoogle Scholar
- Scheringer M, Wania F (2003) Multimedia models of global transport and fate of persistent organic pollutants. In: Fiedler H (ed) Hand-book of environmental chemistry. Springer, Berlin, pp 237–269Google Scholar
- Suntio LR, Shiu WY, Mackay D, Seiber JN, Glotfelty D (1998) Critical review of Henry’s law constants for pesticides. Rev Environ Contam Toxicol 103:1–59Google Scholar