The paper reviews the state of water quality in Ialomita River Basin (IRB), Romania, between 2007 and 2018 using the land use/land cover and basin-specific conditions effects on sediments and nutrients load. On-site monitoring was performed in two control sections of the Ialomita River, one in the upper part of the basin (near Targoviste city) and the second near the discharge into the Danube (downstream of Tandarei town). The statistical averages of water parameters for 10 years' monitoring in the control section that is close to the Ialomita River discharge in Danube were pH = 7.60 (range: 6.41-8.40), NH 4 -N = 1.20 mg/L (0.02-14.87), alkalinity = 4.12 mmol/L (1.34-6.27), NO 3 -N = 2.60 mg/L (0.08-17.30), PO 4 -P = 0.09 mg/L (0-0,31), dissolved oxygen (DO) = 8.87 mg/L (2.72-15.96), BOD 5 = 5.50 mg/L (0.01-74.71), suspended solids (TSS) = 508.32 mg/L (15.2-4457), total dissolved salts (TDS) = 733.69 mg/L (455.2-1053), and river discharge = 38.60 m 3 /s (8. . Expected mean concentration and soil and water assessment tool (SWAT) modeling have been employed in the GIS environment to extend the approach to large spatial patterns within the basin. The estimated average specific emission on the total area for nitrogen was 3.2 kg N/ha, and 0.3 kg P/ha for phosphorus highly influenced by the agricultural activities. The results are useful to raise awareness regarding water-quality degradation and the need to stop and even reverse such trends for local and national sustainable development.Water 2020, 12, 735 2 of 19 water [2]. The discharge of toxic substances, the contamination of groundwater, and the atmospheric transport of nutrients over long distances leading to eutrophication of surface waters, are some of the important processes responsible for the degradation of water quality [3].Massive pollution with organic compounds leads to increased biological oxygen demand and hypoxia, which is often accompanied by severe pathogenic contamination [4]. Eutrophication resulting from the enrichment with nutrients originating from various sources and in particular from agriculture and agro-industrial environment strongly influences the biosphere [5,6]. The over-application of fertilizers damages the ecosystems on large spaces, including soil, water and underground aquifer layers [7]. The main problems associated with intensive agriculture are salinization, nitrification, pesticide contamination and excessive erosion that produce high concentrations of colloids in flowing waters [8].Significant emissions of atmospheric pollutants and long-range transport have affected large areas, while droplets formed in the atmosphere through the combination of water with the gases produced by burning fossil fuels cause acid rain that leads to the acidification of surface waters, especially of lakes [9].Society uses natural resources in a steadily increasing rate. Human influence on nature may cause adverse consequences leading to the disturbance of the natural balance [10,11]. At the same time, technologies and approaches are being developed...
