Total phosphorus is an indicator of too much phosphorus in the water. Because phosphorus attaches to sediment particles, phosphorus and sediment pollution are linked. Phosphorus is an essential nutrient for all plants and animals. Too much phosphorus in the water, however, causes algae to grow in large, dense algal blooms, which depletes oxygen for fish and other marine organisms.

Monitoring water quality in the Maryland Coastal Bays

How is it measured?

Total phosphorus (TP) samples were collected at 74 stations, bimonthly to monthly over the entire year. Data from each sampling station was used to calculate an attainment score based on multiple health-based thresholds. TP scores for each sampling station were then averaged by reporting region.

Threshold Levels

Threshold (mg L-1) Score
<0.025 100
0.025–<0.037 80
0.037–<0.043 60
0.043–<0.1 40
0.1–<0.15 20
≥0.15 0