The deep challenge of nitrate pollution in river water of China

Xin Zhang; Yan Zhang; Peng Shi; Zhilei Bi; Zexuan Shan; Lijiang Ren

doi:10.1016/j.scitotenv.2020.144674

The deep challenge of nitrate pollution in river water of China

Sci Total Environ. 2021 May 20:770:144674. doi: 10.1016/j.scitotenv.2020.144674. Epub 2021 Jan 20.

Authors

Xin Zhang¹, Yan Zhang², Peng Shi³, Zhilei Bi¹, Zexuan Shan¹, Lijiang Ren¹

Affiliations

¹ Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China.
² Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China. Electronic address: zhangy.11b@igsnrr.ac.cn.
³ State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an 710048, China.

PMID: 33513508
DOI: 10.1016/j.scitotenv.2020.144674

Abstract

Nitrate pollution of surface water has attracted global attention, and the issue is becoming increasingly significant in China. To identify the pollution status, sources, and potential non-carcinogenic health risks of nitrate in China's river water, nitrate data from 71 major rivers from 30 provinces were systematically collected. The spatial distribution of nitrate concentrations in river water was analyzed, and the main nitrate pollution sources were revealed based on the presence of nitrogen and oxygen isotopes of nitrate. The results show that approximately 7.83% of samples in China exceeded the national drinking water standard for nitrate (45 mg/L). The concentrations of nitrate in Mudan River (Linkou County), Haihe (Beijing), and Yangtze River estuary (Shanghai) exceed 90 mg/L, which indicates severe pollution. The characteristic values of δ¹⁵N and δ¹⁸O of river water in China range from -23.5‰ to 26.99‰ and - 12.7‰ to 83.5‰, indicate many sources including inorganic fertilizer, soil nitrogen, wastewater or manure. The primary sources of nitrate in river water of Northeast, Northwest, Southwest, and South China were manure, septic waste, inorganic fertilizer, and soil organic matter nitrification. Manure and septic waste were the major source of nitrate in Central, East, and North China. Correlation analysis revealed that the nitrate concentrations of surface water has a positive relationship with GDP, nitrogen fertilizer application usage, wastewater discharge, and population in China. Non-carcinogenic risk of nitrate was identified in 80% of the regions in China, and potential moderate non-carcinogenic risk areas are Shanghai, Beijing, and Shaanxi. It is urgent to solve the problem of pollution and prevent the further pollution of China's river water. Though the new "10-point Water Plan" issued by the Chinese government solved previous problems, it will take decades to control and repair polluted surface water.

Keywords: Nitrate; Pollution; River water; Source; Stable isotopes.

Publication types

Review