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Health risks from large-scale water pollution: Trends in Central Asia
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
2011 (English)In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 37, no 2, 435-442 p.Article in journal (Refereed) Published
Abstract [en]

Limited data on the pollution status of spatially extensive water systems constrain health-risk assessments at basin-scales. Using a recipient measurement approach in a terminal water body, we show that agricultural and industrial pollutants in groundwaters urface water systems of the Aral Sea Drainage Basin (covering the main part of Central Asia) yield cumulative health hazards above guideline values in downstream surface waters, due to high concentrations of copper, arsenic, nitrite, and to certain extent dichlorodiphenyltrichloroethane (DDT). Considering these high-impact contaminants, we furthermore perform trend analyses of their upstream spatial–temporal distribution, investigating dominant large-scale spreading mechanisms. The ratio between parent DDT and its degradation products showed that discharges into or depositions onto surface waters are likely to be recent or ongoing. In river water, copper concentrations peak during the spring season, after thawing and snow melt. High spatial variability of arsenic concentrations in river water could reflect its local presence in the top soil of nearby agricultural fields. Overall, groundwaters were associated with much higher health risks than surface waters. Health risks can therefore increase considerably, if the downstream population must switch to groundwater-based drinking water supplies during surface water shortage. Arid regions are generally vulnerable to this problem due to ongoing irrigation expansion and climate changes.

Place, publisher, year, edition, pages
2011. Vol. 37, no 2, 435-442 p.
Keyword [en]
Aral Sea, Health risk, Pollution, Irrigation, Surface water, Groundwater
National Category
Earth and Related Environmental Sciences
URN: urn:nbn:se:su:diva-53291DOI: 10.1016/j.envint.2010.11.006ISI: 000287620100017OAI: diva2:390379
Available from: 2011-01-21 Created: 2011-01-21 Last updated: 2013-09-05Bibliographically approved
In thesis
1. Basin-scale change in water availability and water quality under intensified irrigated agriculture
Open this publication in new window or tab >>Basin-scale change in water availability and water quality under intensified irrigated agriculture
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Changes in land use and water use can greatly impact the cycling of water and water-borne substances. Increased redistribution of river water to irrigated fields can cause enhanced evapotranspiration and decreased river discharge. Additionally, the water quality can be affected by the external input of fertilisers and pesticides, and by changed pollutant transport pathways in expansive irrigation canal systems. This thesis examines basin-scale changes in water use, river discharge, water quality and nitrogen (N) loading under conditions of intensified irrigated agriculture, using the Aral Sea drainage basin (ASDB) with its two large rivers Syr Darya and Amu Darya in Central Asia as study area. Results show that more efficient irrigation techniques could reduce outtake of river water to the cotton fields in the ASDB by about 10 km3/year, while the corresponding river water saving at the outlet would be 60% lower. The result illustrates the importance of accounting for return flows of irrigation water in basin-scale water saving assessments. Moreover, a decrease in riverine N concentrations at the outlet of the Amu Darya River Basin (ADRB) was observed during a 40-year period of increasing N fertiliser input. The decrease was identified to be primarily caused by increased recirculation of river water in the irrigation system, leading to increased flow-path lengths and enhanced N attenuation. Decreasing N loads were shown to be primarily related to reduced discharge. N export from the basin may further decrease due to projected discharge reductions related to climate change. Furthermore, nutrients and metals were occasionally found at concentrations above drinking water guideline values in surface waters in the ADRB. However, metal concentrations in groundwater in the lower ADRB were subject to orders of magnitude higher health hazards. Projected decrease in downstream surface water availability would thus imply decreased access to water suitable for drinking.

Place, publisher, year, edition, pages
Stockholm: Department of Physical Geography and Quaternary Geology, Stockholm University, 2013. 34 p.
Dissertations from the Department of Physical Geography and Quaternary Geology, ISSN 1653-7211 ; 38
Irrigation, Hydrology, Land-use change, Basin-scale, Central Asia, Aral Sea, Semi-arid, Return flow, Water saving, Health risk, Water quality, Surface water, Groundwater, Nitrogen, Attenuation, Recirculation, Climate change
National Category
Oceanography, Hydrology, Water Resources
Research subject
Physical Geography
urn:nbn:se:su:diva-93214 (URN)978-91-7447-724-5 (ISBN)
Public defence
2013-10-18, William-Olssonsalen, Geovetenskapens hus, Svante Arrhenius väg 14, Stockholm, 13:00 (English)

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 5: Manuscript.

Available from: 2013-09-26 Created: 2013-09-04 Last updated: 2013-09-25Bibliographically approved

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Törnqvist, RebeckaJarsjö, Jerker
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