Seasonal biogeochemical cycles in riverborne groundwater
- Univ. Bern (Switzerland)
- Paul Scherrer Inst., Villigen (Switzerland)
The behavior of dissolved (<0.45{mu}m) inorganic species and changes in relevant properties of anthropogenically polluted river water were investigated during infiltration and movement in a hydraulically connected saturated aquifer. Water from the river and from several sampling wells was analyzed over 5 years for temporal and spatial chemical changes. At the early stage of infiltration, a drastic decrease in pH and in the concentrations of O{sub 2} and NO{sub 3}{sup {minus}} occurs. The gradients in these properties are most significant in the interstitial water of the river sediments. They are the result of the degradation of aquatic biota. The amount and grain morphology of river sediments varies seasonally and depends also on water flow conditions. Temperature-related variations in microbiological activity in the river water and in the sediments of the riverbed induce pronounced annual cycles in the aquifer for several of the investigated properties. Each summer, under anoxic conditions, manganese (hydr) oxides dissolve, and trace metals (Cu, Zn, Cd) are mobilized. The main sources for manganese and other trace elements were found within the river sediments; degradation of algae and other aquatic biota and dissolution of calcite contribute to the observed effects. Higher winter concentrations of O{sub 2} and NO{sub 3}{sup {minus}} result in precipitation of Mn and other redox sensitive elements in the aquifer. Zinc and Cd are retarded by interactions with the aquifer material, whereas Cu is mobile, probably as an organic complex.
- OSTI ID:
- 7066851
- Journal Information:
- Geochimica et Cosmochimica Acta; (United States), Vol. 55:12; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
AQUIFERS
RECHARGE
GROUND WATER
ROCK-FLUID INTERACTIONS
WATER POLLUTION
RIVERS
BIOGEOCHEMISTRY
CADMIUM
CHEMICAL COMPOSITION
COPPER
ENVIRONMENTAL TRANSPORT
MANGANESE
NITRATES
PH VALUE
POLLUTANTS
SEASONAL VARIATIONS
SEDIMENT-WATER INTERFACES
WATER CHEMISTRY
WATER INFLUX
WATER QUALITY
ZINC
CHEMISTRY
ELEMENTS
ENVIRONMENTAL QUALITY
GEOCHEMISTRY
HYDROGEN COMPOUNDS
INTERFACES
MASS TRANSFER
METALS
NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
POLLUTION
STREAMS
SURFACE WATERS
TRANSITION ELEMENTS
VARIATIONS
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
580000 - Geosciences