Triazines in the Marne and the Seine rivers (France): Longitudinal evolution and flows

The transportation pathways of triazines were investigated from their origi ns onwards, in the Marne and the Seine rivers (France). According to the 19 91 survey, the highest total triazine concentration levels (956 ng L-1) wer e found in the river Marne: 580 ng L-1 for atrazine and 200 ng L-1 for sima zine, in relation with agricultural practices. The total triazine levels re ached 829 ng L-1 in the river Seine. The other triazines remained low, from 5 to 75 ng L(-)1. The triazine fluxes were 226 and 404 kg for a 118 d peri od in the Marne and the Seine rivers, respectively. Out of the treatment pe riod, triazine peaks were related to river flows with a 48 hr delay between the peak and the top of the flood. After herbicide treatment, peak concent rations were closely related with the precipitations. Concerning the river Marne tributaries, highest atrazine concentrations were found in June, in t hose which drained the vineyard area. In January, the concentrations were h igher in periurban areas underlining their contribution to the herbicide in puts in the rivers. On the whole, the ratio of triazines transported in the two rivers represented 0.2% of the total amount applicated annually on the ir catchment basins.