"HJ 596.4-2010 Water Quality Vocabulary Part 4" is a standard developed to implement environmental protection laws and regulations, standardize water quality terminology, and protect the environment and human health. This standard is revised from "Water Quality Vocabulary Parts 1 and 2" and "Water Quality Vocabulary Parts 3 to 7" published in 1986 and 1989. This part includes terms and definitions specifically used to describe water quality characteristics, covers corresponding English terms, and has been revised with reference to the international standard "ISO 6107.4-1993 Water Quality Vocabulary Part 4". Effective March 1, 2011, "GB 6816-86" and "GB 11915-89" will no longer apply and will be replaced by this standard. The standard was jointly drafted by the China environment monitoring station and the Liaoning provincial environment monitoring experimental center, and was approved and issued by the Ministry of environment protection on November 5, 2010.