Hydrochemical Characteristics, Ion Source Analysis and Irrigation Water Quality Evaluation of Rivers in Huaibei Plain

The river is an important irrigation water source in the Huaibei Plain. Hydrochemical composition of river water is the result of the interaction with the environment during its development. With the development of regional industry and agriculture, hydrochemistry of rivers have been affected to varying degrees. Therefore, it is very important for river environment management and agricultural production to analyze river hydrochemistry, ion source and irrigation water quality evaluation. In order to understand hydrochemistry characteristics and assessment for irrigation purposes in Huaibei Plain, Sui River and Tang River were selected as the research objects. Twenty-three river water samples were collected and analyzed for major cations and anions. In this study, mathematical statistics, Piper diagrams, Gibbs diagrams, and ion ratio-coefficient were used to analyze hydrochemistry of samples. Sodium salt concentration and F-, Cl- ion concentrations irrigation suitability evaluation systems were used to evaluate rivers. The concentration of pH varied from 8.30 to 9.34 with an average value of 8.62 of Sui River, while that of Tang River ranged from 7.51 to 8.46 with an average value of 8.12. The TDS value of Sui River is relatively high, with a mean value of 1142 mg/L, while that of Tang River is 571 mg/L. Piper diagram shows that chemical type of Sui River changes from Na-Ca-Mg-HCO3-SO4-Cl type in upstream to Mg-Na-SO4-Cl type in downstream. In contrast, the chemical type of Tang River was converted from Ca-Mg-HCO3-Cl type in upstream to Na-Mg-Ca-SO4-HCO3-Cl type in downstream. Gibbs diagram shows that hydrochemical composition of two rivers is mainly affected by rock weathering. The main rock dissolution types are carbonate and halite dissolution, while silicate and gypsum dissolve less. Ion ratio-coefficient diagram display human activities have a significantly stronger impact on Sui River than Tang River. The main affected ions are NO3- and SO42-. Through field investigation, it is speculated that high SO42-in Sui River may be related to waterproof materials used in small factories in downstream. SAR, SC, PI and RSC irrigation suitability evaluation evaluation results show that all sampling points are suitable for irrigation. While the evaluation of irrigation water quality based on concentration of F- and Cl- suggests that caution should be taken when sample S6 and sample S7 are used for irrigation.