Spatial Distribution Characteristics of Hydro-chemistry in Stem Stream of Luo River During Dry Season
The hydro-chemical characteristics of Luo River,the largest first-class tributary of the Henan reach of the Yellow River,were significantly influenced by the intensified human activities,which restricted the sustainable and healthy economic and social development of the the River-basin.In this study,river-water quality monitoring was carried out with 11 sampling points being set up in the stem stream of the River(Luoyang-Gongyi reach),and the water samples were collected during the dry season(December,2023)to study the spatial distribution characteristics of salinity(K+,Na+,Mg2+,Cl-,SO42-and HCO3-)and nutrients(total dissolved nitrogen,total dissolved phosphorus and total dissolved carbon).The results of the monitoring showed that in general,the river-water was weakly alkalic,and total mineralization was equal to 282~448 mg/L with hydro-chemistry type being HCO3-SO4-Ca-Mg.The results of hierarchical clustering indicated that with respect to the content of sa-linity and nutrient,the River-reach was divided into three zones from upstream to downstream,i.e.,relatively low content in Zone Ⅰ(Luoning County-Yiyang County's suburb)and relatively high content in Zone Ⅱ and Zone Ⅲ(Yiyang County-Luoy-ang urban area-Gongyi City).By using Gibbs image model it was showed that salinity ions were mainly affected by weather-ing of silicate rocks;the concentration of total dissolved nitrogen was as high as 3.27 mg/L exceeding the Grade V of the Envi-ronmental Quality Standard for Surface Water,its main component being nitrate nitrogen(accounting for 78.05%).Further-more,the land-use type and correlation analyses indicated that the content of total dissolved nitrogen was mainly affected by agricultural activities and urban domestic wastewater discharge within the River Basin.The achievements of the study could be used as a theoretical basis for the protection of water quality in the River Basin.
Luo River Basinhydro-chemistrysalinitynutrient elementstotal dissolved nitrogennitrate nitrogen