Quantifying water-borne spreading of elements in the Lake Baikal Basin

Jerker Jarsjö, Josefin Thorslund and Jan Pietron Dept. of Physical Geography and Quatenary Geology, Stockholm University e-mail: [email protected]

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Stockholm University

Department of Physical Geography and Quaternary Geology:

    One of the major departments within the Faculty of Science at Stockholm University Has approximately 120 employees and educates approximately 1500 students annually Main research disciplines are Climatology, Ecological Geography, Geographical Data Processing, Geomorphology, Glaciology, Hydrology, Remote Sensing, Tropical Geography, and Quaternary Geology, Education is oriented towards geography and geosciences, including hydrology and environmental protection.

Hydrology group:

1 professor (hydrology, hydrogeology and water resources), 3 assistant professors, 5 post-docs/researchers, 16 PhD students

Collaboration

• Field campaigns, joint modeling and analysis work: Moscow State University, Faculty of Geography, Dep. Hydrology, Mongolian Academy of Sciences, Geography Institute

Methods

• Laboratory and field measurements of hydroclimatic, geochemical and geomorphological parameters • Statistical analyses of hydro(geo)logical and environmental data • Development of basin-scale, predictive hydrological models: -distributed (GIS-based) modelling -sediment transport models (HEC-RAS)

Background:

Permafrost area, ultimately drains into the Arctic Sea Essentially unregulated Unique ecosystems in Lake Baikal and the Selenga River delta Pollution and sediment transport in the Selenga river Basin -Heavy metals from mining -Nutrients from agriculture Russia

Objectives

Confront multi-method field investigations in Baikal Basin with multi-model quantification approaches to investigate fundamental research questions on the transport of substances through large drainage basins and impacts of human activities.

From source to recipient: Example flowpaths and transport times

River basin Stream network Surface water divide Contaminant Source 1 Slow flow through Contaminant Source 2 groundwater Fast flow through stream Streamflow into the sea Coastline Diffuse SGD into the sea Coastal water How much will contaminant sources 1 & 2 contribute to coastal pollution… … if degradation occurs at the same rate in both cases?

Mass delivery fraction: Mass delivery fraction:

The fraction of mass released at a location that reaches the

recipient...

...for a given flow field and degradation rate,

l

.

Method: Destouni, G., Persson, K., Prieto, C. and Jarsjö, J., 2010. General quantification of catchment-scale nutrient and pollutant transport through the subsurface to surface and coastal waters. Environmental Science & Technology, 44(6), 2048–2055 Application: Khadka, S., 2010. Catchment-scale transport through groundwater to surface waters of the Lake Baikal drainage basin, MSc thesis, Stockholm Univ.

Heavy metals spread in dissolved form and with sediments



Estimate total mass flows – and its variance – along the river network (+erosion,deposition/accumulation)

Heavy metal loads (Zaamar): Tuul – Orkhon - Selenga

Measurement locations for C and Q Zaamar Goldfields: Placer mining along Tuul river

’Placer mining’ – alluvial sediments (river bank) Increases sediment and pollutant transport

Estimated mass flows of heavy metals

From: Thorslund, J., Jarsjö, J., Chalov, S.R., and Belozerova, E.V., 2012. Gold mining impact on riverine heavy metal transport in a sparsely monitored region: the upper Lake Baikal Basin case. Journal of Environmental Monitoring, 14, 2780–2792

Main findings

• Mining increases natural transport of dissolved heavy metals by an order of magnitude.

• Transport in suspended phase much higher than the dissolved one • The suspended phase transport increased by 1-2 orders of magnitude

during a single rainfall event

 Mass flows may be underestimated if sampling is infrequent • Hypothesis: High pollution transport in suspension and lower downstream pH can contribute downstream dissolution, explaining why dissolved concentrations are higher farther away from the mining site than on it • Critical question : How long distances can sediments from the mining site be transported?

8000 7000 6000 5000 4000 3000 2000 1000 0 0

Modelled sediment discharge

Increased sediment

discharge where channel slopes are steep (as in the Zaamar Goldfield)

Tuul-Mai n 16Sep2011 00:00:00 50 Main Channel Distance (km) 150 200

Legend

16SEP2011 00:00:00-Sediment Discharge (tons/day) 250 After: Pietron, J., 2012. Modeling sediment transport in the downstream Tuul River, Mongolia, MSc thesis NKA 61, Stockholm Univ.

8000 7000 6000 5000 4000 3000 2000 1000 0 0

Modelled sediment discharge

Sediment deposition (fine particles) just downstream of the Zaamar Goldfield

Tuul-Mai n 16Sep2011 00:00:00 50 Main Channel Distance (km) 150 200

Legend

16SEP2011 00:00:00-Sediment Discharge (tons/day) 250 After: Pietron, J., 2012. Modeling sediment transport in the downstream Tuul River, Mongolia, MSc thesis NKA 61, Stockholm Univ.

Main findings

• Under normal hydrologic conditions, most of the material released by mines is deposited within the first kilometres downstream of the mining area • During peak flow events, the contaminated sediment may be transported further downstream the reach. Consequently, the mining waste sediment can contribute to sediment loads leaving the Tuul River system.

• Higlights the importance of extreme events on overall transport

Future work, plans and possibilities

• • • • • Local transport processes: hydrochemical conditions in different connected water systems: waste ponds, groundwater, channels, river water, suspended material, river sediments Phase transformation processes: equilibrium and/or non-equilibrium Presense of geochemical gradients on different scales (local-regional)?

Implications of local processes for large-scale transport?

Projected future chages: Impact of land use change, water use change and climate change (e.g., methods from parallel work in the Aral Sea basin): average conditions, peak flows, contaminant transport

Internat. Journal papers (Selenga -Baikal) MSc theses (Selenga -Baikal) Internat. Journal papers (Analysis methods)

Publications

Chalov SR, Zavadsky AS, Belozerova EV, Bulacheva MP, Jarsjö J, Thorslund J, Yamkhin J., 2012. Suspended and dissolved matter fluxes in the upper Selenga river basin. Geography Environment Sustainability 5(2): 78-94 Thorslund J, Jarsjö J, Chalov SR, Belozerova EV, 2012. Gold mining impact on riverine heavy metal transport in a sparsely monitored region: the upper Lake Baikal Basin case. Journal of Environmental Monitoring, doi: 10.1039/c2em30643c Pietron, J., 2012. Modeling sediment transport in the downstream Tuul River, Mongolia, MSc thesis NKA 61, Stockholm Univ Khadka, S., 2010. Catchment-scale transport through groundwater to surface waters of the Lake Baikal drainage basin, MSc thesis, Stockholm Univ.

Jarsjö, J., Asokan, S.M., Prieto, C., Bring, A. and Destouni, G., 2012. Hydrological responses to climate change conditioned by historic alterations of land-use and water use. Hydrology and Earth System Sciences, 16, 1335–1347.

Destouni, G., Persson, K., Prieto, C. and Jarsjö, J., 2010. General quantification of catchment-scale nutrient and pollutant transport through the subsurface to surface and coastal waters. Environmental Science & Technology, 44(6), 2048–2055