Contamination of agricultural soils with heavy metals, antibiotics, waste from livestock complexes and toxins leads to the accumulation of these substances in crops and further transmission along the food chain.

Belgorod Region is one of the main agro-industrial regions of Russia. The volume of production of the livestock sector in 2022 amounted to 203 billion rubles. Most often, livestock farms are located near agricultural land with plant crops, which increases the risk of contamination of the latter with various toxicants.

The purpose of this work was to study and assess contamination with heavy metal ions and toxic chemicals of soils of agricultural lands and nearby reservoirs of the Prokhorovsky district of the Belgorod region. As a bioindicator, watercress Lepidium sativum and crustaceans Daphnia magna Straus were used.

5 reservoirs near agricultural lands were investigated. The water in 1,2,3 and 4 samples corresponded to the category of good quality, the D. magna mortality index did not exceed 20%. In sample 5, the mortality index of daphnia did not exceed 30%, that is, acute toxicity was not recorded in these samples.

Soil testing of 3 agricultural lands showed that, on average, the length of the roots of Lepidium sativum was 4±0.2 cm (deviation from the control of 17%), the length of the aboveground part was 15.7±0.4 cm (deviation - 13.3%), the weight of the roots was 630±17 mg (deviation – 10.2%), phytotoxicity - 79±1.2% (very low toxicity).

According to the results of biotesting, the water in reservoirs adjacent to agricultural land corresponds to Class II, the category "slightly polluted". It was revealed that the soils of agricultural lands of the agroholding have initial manifestations of toxic effects. It is necessary to regularly monitor the condition of the soil and, in case of deterioration, take measures to neutralize toxicants.