Study of a vertical profile of pre-emergence herbicide contamination in Middle Garonne sediments.

Damien A. Devault (1) , Chumnan Ith (2) , Georges Merlina (2) , Puy Lim (2) , Eric Pinelli (2)

1 UR HBAN - Hydrosystèmes et Bioprocédés
2 ENSAT - École nationale supérieure agronomique de Toulouse

The fate of pre-emergence herbicides was investigated in sediment cores at sites selected for their nested sedimentation rates. Sediment was segregated in the coarse fraction (>63 µm) and in clays and silts (<63 µm) from the surface to a 45-cm depth. The fine fraction was more contaminated than the coarse fraction, mainly because of desethylatrazine (DEA). However, pesticides were observed in sediments at depths dated to before these compounds were used. Contaminated ancient sediments showed that contaminated elements migrated into the sediment. The fine fraction DEA profile was associated with the chronology of atrazine use. Comparing the sediment age, the half-life of the pesticides studied and banning dates showed that a non-degraded pesticide stock can be established in sediment.

Mots clés: SUBSTITUTED UREAS; S-triazines; Substituted ureas; Anilides; Pesticides; Sediment; Core

Mots clés: ANILIDES

Mots clés: S-TRIAZINES; CORE

Domaines: Ecotoxicologie; Ecologie, Environnement

Damien A. Devault, Chumnan Ith, Georges Merlina, Puy Lim, Eric Pinelli. Study of a vertical profile of pre-emergence herbicide contamination in Middle Garonne sediments.. International Journal of Environmental Analytical Chemistry, 2010, 90 (3-6), pp.311-320. ⟨10.1080/03067310902803383⟩. ⟨hal-02594699⟩