Arrange the following water quality parameters in ascending order of their typical concentration in natural freshwater systems:
1. Nitrates
2. Phosphates
3. Total Dissolved Solids (TDS)
4. Heavy metals (e.g., lead, mercury)
1
4, 1, 2, 3
2
2, 4, 1, 3
3
3, 2, 1, 4
4
1, 2, 3, 4