Monitoring and Evaluation of Timiş River (Banat, Romania) Water Quality Based on Physicochemical and Microbiological Analysis

Flowing water, like rivers, represent an important drinking water source for Romania, their quality being influenced by the quantity of materials in suspension and in colloidal form, and their physicochemical and microbiological characteristics. The Timiş River is generally characterized by the presence of some impurities in natural state, their specific composition being dependant on the nature of the surrounding soils, the soils in the reception basin, waste water spills from different users, and the dissolving capacities of the gases in the atmosphere.

The Timiş River has in general a lower level of mineralization, the sum of mineral salts dissolved being below 280 mg/l and formed of bicarbonate, chloride, nitrate, phosphates, sodium sulphate, potassium, calcium and magnesium coming from the erosion of rocks, soils and precipitations. The concentration of hydrogen ions (pH) is situated around neutral, ranging from 7.3 to 8.8; among the dissolved gases is oxygen, with values ranging between 4.52 and 7.46 mg/l. The main characteristic of the water flow is represented by the variable charge (sometimes appreciable) of materials in suspension and colloidal materials (clay, sand, silica) but also by organic substances, the charge being directly proportional to the meteorological and climate conditions. This charge grows during rainfalls, reaching the maximum during large floods and the minimum during freezing periods (CCOMn max. 30.2 mg O₂). Heavy metals like mercury and arsenic are found in the Timiş waters, but in quantities that do not conclusively affect the water quality, their values being below the maximum allowable amounts.

Bacteriological contamination is also observed. Microorganisms, viruses and protozoa are derived from wastewater spills with human or animal waste, and microorganisms specific to the ecosystem. The total coliforms reach 5x103/100 ml water, the fecal coliforms 2.2x10²/100 ml water, which results in several sectors of the river being classed as lower quality.