The suspended substances of the aquatic ecosystems are formed depending on the nature of the rocks, the soils in the aquatic ecosystems, the character of the precipitations, the hydrological parameters of the river, the metabolic activity of the hydrobionts and the pressure from the human activity. In riparian ecosystems, where human influence is limited, suspended substances and their characteristics are an indicator of the degree of erosion-denudation processes and the ability of chemicals to migrate, being also a basic criterion in determining the state of rivers and their basins. The concentration of the suspended substances determines the turbidity and transparency of the water and, consequently, the penetration of light, the intensity of heating, as well as the absorption processes and the intensity of photosynthesis. All this affects the quality of the water and the activity of the aquatic organisms. And when we talk about the life of aquatic organisms we are referring to the whole food chain of the ecosystem, the disturbance of which can contribute to its degradation, but is also an important part of food and nutrient cycles in lotic ecosystems. In riparian ecosystems with normal activity, the total amount of suspended substances differs depending on the season. During floods the total amount of suspensions is higher due to flooding of adjacent territories and the high speed of the water flow carrying a larger amount of suspensions, compared to the drought season when the amount of particles in the suspensions decreases considerably. For the Prut River in the period February-July 2020, in the winter period (February) small values for the total amount of suspended particles were found. In May-June, higher amounts of suspended substances were determined compared to February, and in July at most stations we also noticed a trend of increasing the total amount of suspended substances. In most of the sampling the total amount of suspended substances was in mineral form.