High levels of nitrogen and phosphorus entering water bodies from urban, industrial, and agricultural areas can cause eutrophication. The indicator is a state indicator and is used to show current nutrient levels and their temporal and spatial variations. The changes in the parameters total nitrogen (TN), nitrate-nitrogen (NO3-N), and orthophosphate-phosphorus (o-PO4-P) in water bodies over time were examined as part of this indicator.
The results of the monitoring programs carried out by the Ministry of Agriculture and Forestry in different basins are evaluated according to the criteria specified in the “By-Law on Surface Water Quality Management”, Annex-5, Table 2, and the current status is determined with respect to the parameters TN, NO3-N and orthophosphate- phosphorus o-PO4-P. For the NO3-N parameter, the water quality in the basins where the measurements were carried out is generally assigned to quality Class I. In contrast, the water quality in Büyük Menderes and the Eastern Black Sea Basins corresponds on average to quality Class II with respect to the parameter TN. For the parameter O-PO4, the water quality can generally be described as Class II[44].
GRAPH 42– BÜYÜK MENDERES BASIN NO3-N (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 43– EAST BLACK SEA BASIN NO3-N (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 44 – ANTALYA BASIN NO3-N (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 45– EASTERN MEDITERRANEAN BASIN NO3-N (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 46– KIZILIRMAK BASIN NO3-N (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 47 – CHANGE OF NO3-N CONCENTRATION IN BASINS BY YEARS
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
In general, for the parameter NO3-N, it can be said that the water quality improved in 2019 compared to 2018. However, there is no regular and significant improvement trend. However, the water quality with respect to this parameter is good across the basins.
GRAPH 48 – BÜYÜK MENDERES BASIN TN (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 49 – EAST BLACK SEA BASIN TN (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 50 – ANTALYA BASIN TN (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 51 – EASTERN MEDITERRANEAN BASIN TN (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 52 – KIZILIRMAK BASIN TN (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 53 – CHANGE OF TN CONCENTRATION IN BASINS BY YEARS
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
As for the TN parameters in the basins, the water quality varies between classes I and II. In this context, the water quality in relation to the parameter TN is good in the basins where the measurement is carried out.
GRAPH 54 – BÜYÜK MENDERES BASIN o-PO4-P (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 55 – ANTALYA BASIN o-PO4-P (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 56 – KONYA CLOSED BASIN o-PO4-P (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 57 – EASTERN MEDITERRANEAN BASIN o-PO4-P (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 58 – EASTERN BLACK SEA BASIN o-PO4-P (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 59 – ÇORUH BASIN o-PO4-P (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 60 – KIZILIRMAK BASIN o-PO4-P (mg/L)
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
GRAPH 61 – CHANGE OF O-PO4-P CONCENTRATION IN BASINS BY YEARS
Source: Ministry of Agriculture and Forestry, General Directorate of Water Management,2021
Looking at the variation of o-PO4-P parameter by years on the basis of the basin areas, we cannot speak of a general trend, but we notice that the water is at the quality level of Class II with respect to this parameter. However, in Büyük Menderes Basin, which was under the influence of intensive urban, agricultural and industrial pressures, this parameter was observed at the quality level of Class IV before 2018 and 2019. On the other hand, an improvement in water quality was observed in 2018 and the Class III quality was achieved with respect to the parameter o-PO4-P. However, in some water bodies in the Büyük Menderes and Antalya basins, a significant deterioration of water quality is observed in 2019 with respect to the parameter o-PO4-P and other parameters[45].
