The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, Estonia
Groundwater pumped from the terrigenous Middle Devonian (D2) aquifer system is naturally rich in iron (Fe), making it a challenge to fulfil the requirements for drinking water quality. The total iron (Fetot) concentrations are above the limit value set for drinking water (0.2 mg/L) in 81% of the ana...
Main Authors: | , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Estonian Academy Publishers
2020-11-01
|
Series: | Estonian Journal of Earth Sciences |
Subjects: | |
Online Access: | https://kirj.ee/wp-content/plugins/kirj/pub/earth-4-2020-281-294_20201111223019.pdf |
id |
doaj-97fe1cd75e844117a408f2cbfb664b43 |
---|---|
record_format |
Article |
spelling |
doaj-97fe1cd75e844117a408f2cbfb664b432021-01-14T11:44:27ZengEstonian Academy PublishersEstonian Journal of Earth Sciences1736-47281736-75572020-11-0169428129410.3176/earth.2020.1710.3176/earth.2020.17The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, EstoniaMariina Hiiob0Enn Karro1Marge Uppin2Kaire Veeperv3Department of Geology, Institute of Ecology and Earth Sciences, University of Tartu, Ravila 14A, 50411 Tartu, Estonia; hiiob@ut.eeDepartment of Geology, Institute of Ecology and Earth Sciences, University of Tartu, Ravila 14A, 50411 Tartu, EstoniaDepartment of Geology, University of Tartu, Vanemuise 46, 51014 Tartu, Estonia; marge13@ut.eeDepartment of Geology, Institute of Ecology and Earth Sciences, University of Tartu, Ravila 14A, 50411 Tartu, Estonia; kaire.veeperv@ut.eeGroundwater pumped from the terrigenous Middle Devonian (D2) aquifer system is naturally rich in iron (Fe), making it a challenge to fulfil the requirements for drinking water quality. The total iron (Fetot) concentrations are above the limit value set for drinking water (0.2 mg/L) in 81% of the analysed water samples. The highest Fetot values reach up to 26 mg/L in some locations of southern Estonia. Due to the reducing conditions in the aquifer system, most of the Fetotconcentrations are caused by a high Fe2+ content. Infiltrated aerobic water becomes anaerobic and Fe3+ reducing along a deep flow path, leading to the downgradient increase in dissolved Fe concentrations. In order to study the natural sources of Fe in the Middle Devonian aquifer system, rock samples from the Narva, Aruküla, Burtnieki and Gauja stages were used for chemical analyses and leaching experiments. The whole-rock chemical analyses showed large variation in the Fe2O3 content (1.20â9.91%), whereas the values were higher in aquifer-forming siltstones than in sandstones. The amount of the leached Fe in groundwater is partly controlled by the granulometric composition of terrigenous rocks. The highest leached Fetot (up to 1.7 mg/L) concentrations were detected in the rocks where the share of the sand fraction is over 70%. As a rule, water is abstracted from sandstones having large pores and good groundwater yield, therefore water quality problems could only be solved by installing Fe removal facilities in southern Estonia.https://kirj.ee/wp-content/plugins/kirj/pub/earth-4-2020-281-294_20201111223019.pdfirondrinking watersandstonesiltstonesedimentary rocksmiddle devonian aquifer systemestonia. |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Mariina Hiiob Enn Karro Marge Uppin Kaire Veeperv |
spellingShingle |
Mariina Hiiob Enn Karro Marge Uppin Kaire Veeperv The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, Estonia Estonian Journal of Earth Sciences iron drinking water sandstone siltstone sedimentary rocks middle devonian aquifer system estonia. |
author_facet |
Mariina Hiiob Enn Karro Marge Uppin Kaire Veeperv |
author_sort |
Mariina Hiiob |
title |
The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, Estonia |
title_short |
The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, Estonia |
title_full |
The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, Estonia |
title_fullStr |
The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, Estonia |
title_full_unstemmed |
The occurrence and geological sources of naturally high iron in the Middle Devonian aquifer system, Estonia |
title_sort |
occurrence and geological sources of naturally high iron in the middle devonian aquifer system, estonia |
publisher |
Estonian Academy Publishers |
series |
Estonian Journal of Earth Sciences |
issn |
1736-4728 1736-7557 |
publishDate |
2020-11-01 |
description |
Groundwater pumped from the terrigenous Middle Devonian (D2) aquifer system is naturally rich in iron (Fe), making it a challenge to fulfil the requirements for drinking water quality. The total iron (Fetot) concentrations are above the limit value set for drinking water (0.2 mg/L) in 81% of the analysed water samples. The highest Fetot values reach up to 26 mg/L in some locations of southern Estonia. Due to the reducing conditions in the aquifer system, most of the Fetotconcentrations are caused by a high Fe2+ content. Infiltrated aerobic water becomes anaerobic and Fe3+ reducing along a deep flow path, leading to the downgradient increase in dissolved Fe concentrations. In order to study the natural sources of Fe in the Middle Devonian aquifer system, rock samples from the Narva, Aruküla, Burtnieki and Gauja stages were used for chemical analyses and leaching experiments. The whole-rock chemical analyses showed large variation in the Fe2O3 content (1.20â9.91%), whereas the values were higher in aquifer-forming siltstones than in sandstones. The amount of the leached Fe in groundwater is partly controlled by the granulometric composition of terrigenous rocks. The highest leached Fetot (up to 1.7 mg/L) concentrations were detected in the rocks where the share of the sand fraction is over 70%. As a rule, water is abstracted from sandstones having large pores and good groundwater yield, therefore water quality problems could only be solved by installing Fe removal facilities in southern Estonia. |
topic |
iron drinking water sandstone siltstone sedimentary rocks middle devonian aquifer system estonia. |
url |
https://kirj.ee/wp-content/plugins/kirj/pub/earth-4-2020-281-294_20201111223019.pdf |
work_keys_str_mv |
AT mariinahiiob theoccurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia AT ennkarro theoccurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia AT margeuppin theoccurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia AT kaireveeperv theoccurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia AT mariinahiiob occurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia AT ennkarro occurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia AT margeuppin occurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia AT kaireveeperv occurrenceandgeologicalsourcesofnaturallyhighironinthemiddledevonianaquifersystemestonia |
_version_ |
1724338246543998976 |