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The global dimension of Arsenic in ground- and drinking water Chairman: Tony Appelo Welcome! Why, and what is the problem, some background Introduction of the speakers. Smedley and Kinniburgh, 2002, AG 17, 517. The Global Arsenic Problem. Bangladesh Groundwater. DPHE and BGS, 2001.
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The global dimension of Arsenic in ground- and drinking water • Chairman: Tony Appelo • Welcome! • Why, and what is the problem, some background • Introduction of the speakers
Smedley and Kinniburgh, 2002, AG 17, 517 The Global Arsenic Problem
Bangladesh Groundwater DPHE and BGS, 2001
Bangladesh Standard: 0.05 mg/L. Drink 2 L → 0.1 mg As /day In rice: 0.03 - 0.3 mg/kg Eat 0.3 kg → 0.1 mg As /day (Kapaj et al., 2006, JESH 41, 2399)
O Fe O H2O Fe2O3 surface surface site ≡FeOH The hydration of Fe-oxide surfaces ≡FeOH + H+ ↔ ≡FeOH2+ ≡FeOH - H+ ↔ ≡FeO-
2 redox forms in water: Arsenate anion, As(5)Arsenic acid, As(3) pH = 6.76 5 5 3 3
PZC Sorption of anions on ferrihydrite
PROGRAM 14.15 dr Pauline Smedley (British Geol Survey): Arsenic in groundwater – natural sources, mobilisation controls and the question of human influences 15.00 Prof. dr Marie Vahter (Karolinska Institute): Arsenic in drinking water: threatening the health of millions? 15.45 Break 16.15 Tony Appelo: What is the origin of high As concentrations in groundwater? 16.45 Discussion 17.00 Closure, drinks, etc.