Аннотация:The present study is particularly devoted to link geochemical flux and climate
and land use changes in the Selenga river catchment. Results indicate that
high sediment loads were reported both for altered and natural rivers. Reported
multi-decadal declines in sediment loads in the downstream part of Selenga
River can be attributed to the abandonment of cultivated lands and changing
hydroclimatic factors, such as in particular climate-driven decrease of water
flows and intensified water use for irrigation purposes. Empirical sediment rating
curves show that a series of peak flow events during spring and summer
contribute to the main part (up to 98 %) of the annual sediment and pollution
loads. The highest contribution of flood sediment load was obtained for the
particular wet years, the lowest - for the dry, which is generally reflects the
increase of water runoff during high floods in annual flow. Whereas sediment
flows were connected with the hydroclimatic conditions in the catchment, elemental
composition of the mass flows mostly relate to the soil/petrologic conditions.
With the exception of small impacted rivers where water quality impacts
associated with mining were found, the formation of elemental compositions
and sediment-associated chemical constituents generally reflects catchment
characteristics