- Statement I: A BOD value of 4 ppm and a dissolved oxygen level of 8 ppm indicate that the water has a good quality because the dissolved oxygen should be higher than the BOD to support aquatic life.
- Statement II: If the concentration of zinc and nitrate is 5 ppm, this is within permissible limits for drinking water, indicating good quality.
Both statements are correct as they provide accurate interpretations of water quality standards.