Figure 1
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Data sources:
Data was provided by National Environmental Agency of the Ministry of Environmental Protection and Agriculture under the ENI SEIS II East project activities
Note: The data series are calculated as the average of annual mean concentrations of phosphate (mg P/l) (top) and nitrate (mg NO3-N/l) for river sites in the two major river basins of Georgia (Black Sea and Caspian Sea basins) and for the whole country for the period 2004-2018. The total number of river sites is given in parenthesis. The data series are calculated as the annual mean concentrations of phosphate (mg P/l) (bottom left) and nitrate (mg NO3-N/l) (bottom right) for Lake Paliastomi for the period 2004-2018.
Average river nitrate and phosphate concentrations in the Black Sea river basin have been fairly stable over the time period 2004-2018. For nitrate there has been a slight decrease (16%) when comparing the last three years to the first three years.
For the Caspian Sea river basin there was a marked increase for both phosphate and nitrate concentration, with phosphate being more than three times higher at the end of the time series and
a doubling for nitrate. The middle of the time series should be treated with some caution, due to lower number of samples per year. This goes in particular for the years 2011-13 and the Caspian Sea basin. This can explain the higher concentrations observed in these years.
Phosphate concentrations in Lake Paliastomi decreased sharply at the start of the time series and have been relatively stable since 2008. The nitrate concentrations have been highly variable. The lowest values were observed in 2012-2014.