the quality of the water from beijing to tianjin is worse than grade v. the key pollution indicators are ammonia nitrogen, petroleum, potassium permanganate index and volatile phenol.
北京入天津境内水质为劣ⅴ类。主要污染指标是氨氮、石油类、高锰酸盐指数、挥发酚。
the key pollution indicators are ammonia nitrogen, petroleum, potassium permanganate index and volatile phenol.