Metal contamination budget at the river basin scale: an original Flux-Flow Analysis (F2A) for the Seine River

摘要

Material flow analysis and environmental contamination analysis are mergedinto a Flux-Flow analysis (F2A) as illustrated for the metal circulation inthe Seine River catchment. F2A combines about 30 metal flows in theanthroposphere (14 million people) and/or metal fluxes in the environment(atmosphere, soils, and aquatic system) originating from two dozens ofsources. The nature and quality of data is very heterogeneous going fromdownscaled national economic statistics to upscaled daily environmentalsurveys.A triple integration is performed: space integration over the catchment(65 000 km2), time integration for the 1950–2000 trend analysed at5 year resolution, and a conceptual integration resulting in two F2Aindicators.Despite the various data sources an average metal circulation is establishedfor the 1994–2003 period and illustrated for zinc: (i) metal circulation inthe anthroposphere is now two orders of magnitude higher than river outputs,(ii) long term metal storage, and their potential leaks, in soils,wastedumps and structures is also orders of magnitude higher than presentriver fluxes. Trend analysis is made through two F2A indicators, the percapita excess load at the river outlet and the leakage ratio (excessfluxes/metal demand). From 1950 to 2000, they both show a ten foldimprovement of metal recycling while the metal demand has increased by 2.5to 5 for Cd, Cu, Cr, Pb and Zn, and the population by 50%.