| | | | | | 1. | | | | | | | 7︱8 | | | | 2. 7—10 | 20 | | | | | | | | 2—3 24 | 5mg/L | pH | | | | | | 3. | | | | | | | | | | | | | | 4. | | | | | | | | | | | | | | | | | | | | | | 2022 1 2 |