『Abstract
Aquatic geochemistry on watershed background helps elucidate
the influence of natural processes and anthropogenic activities
to the environment. The 87Sr/86Sr ratios
and dissolved loads were measured in 35 water samples from the
Huanghe and Xijiang River drainage basins. The dissolved loads
and 87Sr/86Sr ratios differed considerably
between the two drainage basins. The 87Sr/86Sr
ratios of the Xijiang River are between 0.70856 and 0.70936, with
an average of 0.70894, reflecting weathering of carbonate minerals
as the dominant source and anthropogenic pollution as the secondary
one, especially in the upper reach tributaries, while the Sr isotopic
ratios in the Huanghe River range from 0.70986 to 0.71139 averaging
0.71118 that results primarily from evaporite dissolution. Precipitation
contributes to 2.8% and 5.7% to the chemistry of the Xijiang and
Huanghe River, respectively. Evaporite dissolution and silicate
weathering account for 79.4% and 11.3%, respectively, in the Huanghe
River while carbonate dissolution and silicate weathering account
for 75.4% and 14.6%, respectively, in the Xijiang River. The chemical
weathering rate is 107.6 t/km2/yr in the Xijiang River
drainage basin, and 34.2 t/km2/yr in the Huanghe River
drainage basin. The CO2 consumption budget
is 305.2×109 mol/yr in the Xijiang River drainage basin,
and 147.9×109 mol/yr in the Huanghe River drainage
basin.
Keywords: Strontium; 87Sr/86Sr; Carbon sequestration;
Water pollution; CO2 consumption budget;
Water chemistry』
1. Introduction
2. River setting
3. Sampling and analytical procedures
4. Results and discussion
4.1. Characteristics of the major elements
4.2. Strontium concentration and strontium isotope composition
4.2.1. The Xijiang River
4.2.2. The Huanghe River
4.3. Sources of the dissolved major elements and strontium
4.3.1. Anthropogenic activities
4.3.2. Atmospheric dry and wet deposition
4.3.3. Rock weathering
4.4. Chemical budget and chemical weathering rate estimation
4.4.1. Chemical budget
4.4.2. Chemical weathering estimation
5. Conclusions
Acknowledgements
References