Hg Wallis soils 2021

Surface soils (0-10 cm) were collected in May 2021 from 200 sites in the Rhone valley in the region of Visp, in the Canton of Valais, Switzerland. The study area exhibited soils with varying levels of mercury (Hg) contamination. The soil Hg contamination within the surveyed area, covering 8.6 squared km, is primarily linked to the drainage canal known as the ``Grossgrundkanal''. This canal traverses a chemical manufacturing facility in Visp (Forum Umwelt in 2011). During the period from approximately 1930 to 1976, water contaminated with mercury, carrying 50 to 200 tons of Hg, was directed into the canal, leading to the contamination of the canal sediments. The sediments were routinely dredged and subsequently utilized as fertilizer on agricultural soils and gardens. Additionally, until the year 1990, these sediments were employed as fill material in settlement areas.