Phosphorus in Lake Sevan

The chart shows the mean annual concentration of total phosphorus at the Big Sevan and Small Sevan observation points, in mg of P per litre, for 2019-2024.

In 2024 the mean at Big Sevan was 0.11 mg P/l, the highest of the six years; the lowest, 0.071, was recorded in 2020. At Small Sevan it was 0.071 in 2024. Over the six years the values at that point ranged from 0.064 (2022) to 0.077 (2023).

The Small Sevan value is lower than the Big Sevan value in 2019-2022 and 2024, and in 2023 both are 0.077. Each mean rests on 9 to 12 samples, except Small Sevan in 2021, when only 2 samples were taken.