The Derivation of Nutrient Criteria for the Adjacent Waters of Yellow River Estuary in China.

Ecological protection and high-quality development of the Yellow River basin are becoming part of the national strategy in recent years. The Yellow River Estuary has been seriously affected by human activities. Especially, it has been severely polluted by the nitrogen and phosphorus from land sources, which have caused serious eutrophication and harmful algal blooms. Nutrient criteria, however, was not developed for the Yellow River Estuary, which hindered nutrient management measures and eutrophication risk assessment in this key ecological function zone of China. Based on field data during 2004–2019, we adopted the frequency distribution method, correlation analysis, Linear Regression Model (LRM), Classification and Regression Tree (CART) and Nonparametric Changepoint Analysis (nCPA) methods to establish the nutrient criteria for the adjacent waters of Yellow River Estuary. The water quality criteria of dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP) are recommended as 244.0 µgL⁻¹ and 22.4 µgL⁻¹, respectively. It is hoped that the results will provide scientific basis for the formulation of nutrient standards in this important estuary of China. [ABSTRACT FROM AUTHOR]