STATISTICAL ANALYSIS OF HYDROCHEMICAL PARAMETERS OF DRAINAGE AND WASTE WATERS FROM A RICE IRRIGATION SYSTEM

Purpose: statistical analysis of hydrochemical parameters of drainage and waste water (DWW) from a rice irrigation system located in the Bagaevsky district Rostov region. Materials and methods. The object of the study was a rice irrigation system in the Bagaevsky district Rostov region. Theoretical studies are based on the Laplace theory of normal distribution and are carried out in Microsoft Excel. Results and discussion. The following parameters that regularly exceed the maximum permissible concentrations for water bodies of fishery importance (MPCrh) in the studied collectors for the period 2019–2024: sulfates, calcium, magnesium, total iron, phosphate ions – were determined. The long-time average annual concentration of the indicators in the drainage and waste waters of the first and second collectors was: for sulfates – 1038.6 and 673.03, calcium – 203.41 and 185.55, magnesium –95.89 and 75.99, phosphate ions – 0.19 and 0.26, total iron – 0.17 and 0.2 mg/dm³, respectively. The dynamics of the “dry residue” indicator during the irrigation season in the two studied collectors for the period 2019–2024 is presented. The long-time average annual value of this indicator for the first collector was 1414.7 mg/dm³, for the second collector – 1816.04 mg/dm³. Conclusions. It was found that in the first collector the most frequently occurring concentrations of iron and nitrite ions in the DWW are in the ranges not exceeding the MPCrx, the values of other indicators regularly exceed the maximum permissible concentrations. In the DWW of the second collector, a regular excess of the MPCrx was determined for the following indicators: sulfates, calcium, magnesium, phosphates, chlorides, total iron. DWW with a high content of nitrite ions and iron compounds have a toxic and mutagenic effect on living organisms of natural aquatic ecosystems. When reusing such water for irrigation or discharging it into a water body, it is necessary to correct the chemical composition of the DWW.