TY - JOUR
T1 - Preliminary evidence of a link between surface soil properties and the arsenic content of shallow groundwater in Bangladesh
AU - Van Geen, A.
AU - Aziz, Z.
AU - Horneman, A.
AU - Weinman, B.
AU - Dhar, R.K.
AU - Zheng, Y.
AU - Goodbred, S.
AU - Versteeg, R.
AU - Seddique, A.A.
AU - Hoque, M.A.
AU - Ahmed, K.M.
PY - 2006/1/1
Y1 - 2006/1/1
N2 - The extremely heterogeneous distribution of As in Bangladesh groundwater has hampered efforts to identify with certainty the mechanisms that lead to extensive mobilization of this metalloid in reducing aquifers. We show here on the basis of a high-resolution transect of soil and aquifer properties collected in Araihazar, Bangladesh, that revealing tractable associations between As concentrations in shallow (< 20 m) groundwater with other geological, hydrological, and geochemical features requires a lateral sampling resolution of 10–100 m. Variations in the electromagnetic conductivity of surface soils (5–40 mS/m) within a 500 m × 200 m area are documented with 560 EM31 measurements. The results are compared with a detailed section of groundwater As concentrations (5–150 μg/L) and other aquifer properties obtained with a simple sampling device, “the needle-sampler”, that builds on the local drilling technology. By invoking complementary observations obtained in the same area and in other regions of Bangladesh, we postulate that local groundwater recharge throughout permeable sandy soils plays a major role in regulating the As content of shallow aquifers by diluting the flux of As released from reducing sediments.
AB - The extremely heterogeneous distribution of As in Bangladesh groundwater has hampered efforts to identify with certainty the mechanisms that lead to extensive mobilization of this metalloid in reducing aquifers. We show here on the basis of a high-resolution transect of soil and aquifer properties collected in Araihazar, Bangladesh, that revealing tractable associations between As concentrations in shallow (< 20 m) groundwater with other geological, hydrological, and geochemical features requires a lateral sampling resolution of 10–100 m. Variations in the electromagnetic conductivity of surface soils (5–40 mS/m) within a 500 m × 200 m area are documented with 560 EM31 measurements. The results are compared with a detailed section of groundwater As concentrations (5–150 μg/L) and other aquifer properties obtained with a simple sampling device, “the needle-sampler”, that builds on the local drilling technology. By invoking complementary observations obtained in the same area and in other regions of Bangladesh, we postulate that local groundwater recharge throughout permeable sandy soils plays a major role in regulating the As content of shallow aquifers by diluting the flux of As released from reducing sediments.
U2 - 10.1016/j.gexplo.2005.08.106
DO - 10.1016/j.gexplo.2005.08.106
M3 - Article
SN - 0375-6742
VL - 88
SP - 157
EP - 161
JO - Journal of Geochemical Exploration
JF - Journal of Geochemical Exploration
IS - 1-3
ER -