Wastewater

Engineering

Ecology

Biology

Pollution

Geotechnical engineering

China

Archaeology

Beijing

Septic tank

Manure

Environmental engineering

Surface water

Fertilizer

Geography

Hydrology (agriculture)

Environmental chemistry

Agronomy

Environmental science

Chemistry

Water pollution

Nitrate

The Science of The Total Environment

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 δ 15 N and δ 18 O 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. • The pollution of nitrate in river water increased gradually from west to east. • The distribution nitrate pollution was uneven from north to south. • The sources of nitrate in river water are varied and blending of mult-sources. • Nitrate pollution was impacted by GDP, fertilizer, wastewater, population. • 80% of China present non-carcinogenic health risks, especially for children.

The deep challenge of nitrate pollution in river water of China