Fig. 2: Site sediment vertical profiles.
From: Arsenic contamination of Bangladesh aquifers exacerbated by clay layers
a Conventional radiocarbon (14C) ages expressed in thousands of years (kyr) measured on fossil plant material embedded in the sediment and/or total organic carbon of the clay layers. b Total calcium (Ca) content determined by X-ray fluorescence. c Diffuse spectral reflectance between 530 and 520 nm (ΔR). d Percentage of Fe(II) within the total Fe extractable by 1 N hot HCl. Sand color, quantified by ΔR and dictated by Fe speciation, is explicitly displayed to visualize orange and gray sand distribution. Results from the four multi-level well nest boreholes and the additional coring location are combined in the graphics and were used to prepare the generic site lithology displayed on the right.
