Arsenic in de Dutch subsoil

...Introduction...

Tony Appelo

• Welcome!

• Concentration patterns

• Introduction of the speakers

Arsenic concentrations in groundwater

D.J. Huisman, TNO

Pleistocene, low sealevel

In groundwater: about 5000 ppb Fe2+, 5 ppb As

Iron ore (’oer’) in Salland, NL

Ratio Fe / As in FeOOH is about 1000

Holocene, sealevel riseFeOOH transforms with S from seawater in pyrite, FeS2

Ratio Fe / As in FeS2 is about 1000

Vegetation grows, peat develops...

Peat is exploited

FeS2 aerated, oxidizesFeS2 retransforms in solid FeOOH, FeCO3 and SO4

2-, Fe2+, As

Ratio Fe / As in water is ???

What is the relation among

As and

SO42-, Fe2+, .... ??

PROGRAM of the morning

11.00 dra Sophie Vermooten (TNO, Utrecht) : Regional occurrence of As in the Netherlands

11.30 Prof. dr Pieter Stuyfzand (VU, Amsterdam / KIWA, Nieuwegein): As in the Dutch drinkingwater production

12.00 drs Slavek Vaşak (TNO, Utrecht) : IGRAC's inventory of hazardous substances in groundwater on global scale

12.15 discussion

12.30 Lunch