EMEP Contribution to the Preparatory Work for the Review of the CLRTAP Protocol on POPs. New Substances: Model Assessment of Potential for Long-range Transboundary Atmospheric Transport and Persistence of Endosulfan

MSC-E Information Note 10/2005

N. Vulykh, S. Dutchak, E. Mantseva, V. Shatalov

ABSTRACT

Endosulfan is used as a wide-range pesticide with acaricide properties against a variety of insects and some mites. It is used to disinfect seeds and to kill pests on potato, vegetable, fruit, tea, tobacco and cotton crops. It can also be used in flower cultivation and wood preservation. Thiodan (a commercial name of endosulfan) began to be widely used in agriculture in the mid-1950s. Endosulfan and endosulfan-bearing products were used and are still used in many European countries [European Directory of Agrochemical Products, N330]. The most detailed information on the use of endosulfan in agriculture of European countries is given in [Herrmann, 2004].

Endosulfan as a potential candidate for the inclusion into the UN-ECE Protocol on POPs was addressed by the Ad Hoc Expert Group on POPs [Lerche et al., 2002].

A preliminary risk profile of Endosulfan prepared by the national expert [Herrmann, 2004] testifies that its characteristics meet the criteria outlined in the Executive Body Decision 1998/2 and it may be a candidate for the inclusion into the UN-ECE Protocol on POPs. Additional information on the evaluation of this product in accordance with the two criteria: potential for long-range transboundary atmospheric transport (LRTP) and persistence can be provided by the model assessment.

Endosulfan is a mixture of two stereoisomers - a-endosulfan è b-endosulfan. The proportion of a-and b-isomers in the technical endosulfan is reported as either 4:1 [Melnikov et al., 1995] or 2:1 and 7:3 [Herrmann, 2004]. The purity of the technical product does not exceed 94%, it also contains 2% of endosulfan alcohol and 1% of endosulfan ether as admixtures.

To evaluate the potential of endosulfan isomers for the long-range transboundary atmospheric transport and persistence in the environment, the EMEP/MSCE-POP multicompartment hemispheric transport model has been used. A multicompartment approach is conditioned by the ability of POPs to be accumulated in soil, seawater and vegetation with subsequent re-emission. To model atmospheric transport of the considered substances the information on their physical-chemical properties (see Annex) as well as meteorological and geophysical data has been used. More detailed information on the structure of the model and parameterisation of the media processes can be found in the EMEP/MSC-E reports [Shatalov et al., 2003; Dutchak et al., 2004].

To estimate LRTP and persistence of endosulfan isomers with the help of the EMEP/MSCE-POP model calculations of their transport from a conventional point emission source located in Europe (France) were made for a one-year period.