TY - JOUR
T1 - The link between surface water and groundwater-based drinking water – strontium isotope spatial distribution patterns and their relationships to Danish sediments
AU - Frei, Robert
AU - Frei, Karin M.
AU - Kristiansen, Søren Munch
AU - Jessen, Søren
AU - Schullehner, Jörg
AU - Hansen, Birgitte
N1 - Funding Information:
RF is thankful to Carlsberg Foundation 's support for new analytical facilities (mass spectrometers), through grants 2012-01-071 and CF17-102 . KMF acknowledges support by the Carlsberg Foundation through the project entitled “Tales of Bronze Age Women” CF-15 0878 and through the “Semper Ardens” research CF18-0005 (Tales of Bronze Age People).
Publisher Copyright:
© 2020 The Author(s)
PY - 2020/10
Y1 - 2020/10
N2 - The hydrological relationship between surface waters and groundwaters in many regions of the world is well known and the effects of their mutual interaction and interaction with the soils and bedrocks, with respect to resulting changes in their chemical composition, are well studied. In this study we add to this knowledge by comparing the distributional patterns of strontium (Sr) isotopes in previously published 192 surface water samples with those of newly acquainted Sr isotope data from groundwater-based drinking water samples extracted from 163 of the major waterworks in Denmark. The aim is to investigate potential compositional changes that might derive from the interaction with the aquifer lithology or overlying sediments and soils. The average Sr isotope signatures of surface and groundwater-based drinking waters define 87Sr/86Sr values of 0.7096 ± 0.0015 (2σ) and 0.7088 ± 0.0013 (2σ), respectively. The skewed distribution of Sr isotope compositions in groundwaters towards lower 87Sr/86Sr values indicates enhanced contribution of natural carbonate-derived strontium with depth, while slightly elevated 87Sr/86Sr signatures in surface waters may reflect the diminished contribution of Sr from carbonates in the glaciogenic sediments due to their progressive acid dissolution. Strontium concentrations [Sr] in groundwater-based drinking water from the participating major waterworks define a country-wide average of 1.17 mg/L and the distributional pattern shows an East – West decreasing trend. Lowest concentrations are found in the West Jutland glaciogenic province (WJGP; average [Sr] = 0.36 mg/L) and in the northernmost tip of Jutland. A corresponding pattern, although less pronounced, is also depicted by the 87Sr/86Sr signatures of groundwater-based drinking water, whereby increasing 87Sr/86Sr values from Zealand through Funen into the Jutland peninsula correspond with increasing thickness of glaciogenic overburden providing (though mass-balance wise subordinate) radiogenic Sr to the natural carbonate-dominated groundwaters. The highest 87Sr/86Sr values are recorded in waters from northern Jutland, possibly reflecting the admixture of radiogenic strontium from late glacial and post-glacial glacio-isostatic adjustment-related marine aquifers. Generally, the surprisingly rather homogeneous and similar distributional patterns of 87Sr/86Sr signatures of Danish aquifers and surface waters implies a strong and dominant control of Sr by natural clastic (reworked) carbonate components in the Quaternary, Miocene and Holocene sediments, and to lesser degree (with the exception of northern central Jutland and Eastern Zealand) from the pre-Quaternary limestone dominated “basement” directly. Our results are consistent with a tight hydrological and geochemical interrelationship between surface waters and groundwaters in Denmark. There is a need for further investigations of the effects of advanced treatment of soft (acidic) groundwater-based drinking water on the concentrations and isotopic signatures of trace elements such as Sr. However, our study lends support for the adequate use of Sr isotope signatures of either of these waters to characterize the isotope compositional range of bioavailable fractions relevant for authenticity identification, forensic studies, and for prehistoric and modern human and animal proveniencing.
AB - The hydrological relationship between surface waters and groundwaters in many regions of the world is well known and the effects of their mutual interaction and interaction with the soils and bedrocks, with respect to resulting changes in their chemical composition, are well studied. In this study we add to this knowledge by comparing the distributional patterns of strontium (Sr) isotopes in previously published 192 surface water samples with those of newly acquainted Sr isotope data from groundwater-based drinking water samples extracted from 163 of the major waterworks in Denmark. The aim is to investigate potential compositional changes that might derive from the interaction with the aquifer lithology or overlying sediments and soils. The average Sr isotope signatures of surface and groundwater-based drinking waters define 87Sr/86Sr values of 0.7096 ± 0.0015 (2σ) and 0.7088 ± 0.0013 (2σ), respectively. The skewed distribution of Sr isotope compositions in groundwaters towards lower 87Sr/86Sr values indicates enhanced contribution of natural carbonate-derived strontium with depth, while slightly elevated 87Sr/86Sr signatures in surface waters may reflect the diminished contribution of Sr from carbonates in the glaciogenic sediments due to their progressive acid dissolution. Strontium concentrations [Sr] in groundwater-based drinking water from the participating major waterworks define a country-wide average of 1.17 mg/L and the distributional pattern shows an East – West decreasing trend. Lowest concentrations are found in the West Jutland glaciogenic province (WJGP; average [Sr] = 0.36 mg/L) and in the northernmost tip of Jutland. A corresponding pattern, although less pronounced, is also depicted by the 87Sr/86Sr signatures of groundwater-based drinking water, whereby increasing 87Sr/86Sr values from Zealand through Funen into the Jutland peninsula correspond with increasing thickness of glaciogenic overburden providing (though mass-balance wise subordinate) radiogenic Sr to the natural carbonate-dominated groundwaters. The highest 87Sr/86Sr values are recorded in waters from northern Jutland, possibly reflecting the admixture of radiogenic strontium from late glacial and post-glacial glacio-isostatic adjustment-related marine aquifers. Generally, the surprisingly rather homogeneous and similar distributional patterns of 87Sr/86Sr signatures of Danish aquifers and surface waters implies a strong and dominant control of Sr by natural clastic (reworked) carbonate components in the Quaternary, Miocene and Holocene sediments, and to lesser degree (with the exception of northern central Jutland and Eastern Zealand) from the pre-Quaternary limestone dominated “basement” directly. Our results are consistent with a tight hydrological and geochemical interrelationship between surface waters and groundwaters in Denmark. There is a need for further investigations of the effects of advanced treatment of soft (acidic) groundwater-based drinking water on the concentrations and isotopic signatures of trace elements such as Sr. However, our study lends support for the adequate use of Sr isotope signatures of either of these waters to characterize the isotope compositional range of bioavailable fractions relevant for authenticity identification, forensic studies, and for prehistoric and modern human and animal proveniencing.
KW - Denmark
KW - Distributional pattern
KW - Drinking water
KW - Groundwater
KW - Strontium isotopes
UR - http://www.scopus.com/inward/record.url?scp=85089283017&partnerID=8YFLogxK
U2 - 10.1016/j.apgeochem.2020.104698
DO - 10.1016/j.apgeochem.2020.104698
M3 - Article
AN - SCOPUS:85089283017
SN - 0883-2927
VL - 121
JO - Applied Geochemistry
JF - Applied Geochemistry
M1 - 104698
ER -