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