A film about the ecological state of Lake Peipsi, located on the territory of the RSFSR (eastern part) and Estonia (western part). 1 part Tartu region, vil. Nina. Sandy beaches of Lake Peipsi. Local residents are engaged in gardening and fishing. They talk (sync. And behind the scenes) about their impressions of the lake. Some believe that over time, the water in the lake has changed for the worse, others claim that the water has not changed, but they are a minority. Fishing farm in the village of Praata at the mouth of the river. Emaiegi. Fishermen carry boxes of fish to the boat. A local fisherman [Axel Kyykh] tells (sync.) That changes in the water in the river affect the taste of the fish caught. Fertilization of fields with chemical and organic compounds, a livestock complex with farms, a waste settler and [feed dispenser] on the shores of Lake Peipsi. With melt and rainwater, chemicals and fertilizers from the ground fall into the water. The mineralization of water increases. Arve [Meaimets], a specialist in the study of lakes, says (sync. In Estonian) about an increase in the content of nutrients in the water of Lake Peipsi by 3-6 times. A street in the city of Tartu with the Emajõgi River, where waste water from all enterprises in the city is discharged without purification. Wastewater treatment plants in the towns of [Võru] and Põlva. The senior master of the wastewater treatment plant in Põlva [Marek Ivask] says (sync. And behind the scenes in Estonian) that their wastewater treatment plant does not purify wastewater from chemical compounds. Part 2 1st Deputy Chairman of the Pskov Regional Executive Committee G.N. Bubnov speaks (sync. And behind the scenes) about the need to treat wastewater entering the Pskov-Peipsi Lake. The 1st Deputy Chairman of the Council of Ministers of the Estonian SSR Indrek Herbertovich Toome says (sync. And behind the scenes in Estonian) that the number of industrial enterprises in Estonia has recently increased, and hence the amount of industrial wastewater. Scientific research of Lake Peipsi water in the laboratory. Computing technology and chemical equipment for studying the processes occurring in the lake. Expedition of the [hydrological] laboratory on the research vessel, the staff on the deck raise water from Lake Peipsi for analysis. The head of the work on the ship, biologist Peter [Miges] says (sinhr. In Estonian) that their laboratory has been studying the water in Lake Peipsi for only the second year and it is too early to draw any conclusions. Biologist Ervin Robertovna Pihu tells (sync. And off-screen in Estonian) that Lake Peipsi began to age and that human activities (household, agricultural, industrial) contribute to this. In the Druzhba collective farm (Pskov region), to increase fish stocks in the spring, fishermen put down a special net in which it is convenient for fish to spawn. Workers of the Peipsi Kalur collective farm (Estonian SSR, the village of Kallaste) artificially fertilize eggs and raise whitefish and pike fry in an incubator. Camping on the shores of Lake Peipsi. Vacationers sunbathe on the beach, swim in boats and pedal boats on the water of the lake. Employees of the Kohtla-Järve forestry enterprise are posting notices prohibiting signs, diagrams of the shoreline of Lake Peipsi, where places prohibited for tourists to stop are shown, and they are installing poles blocking the way for cars. Police officers conduct interviews with undisciplined vacationers and ask them to leave unauthorized resting places. Officials of the State Traffic Inspectorate (GAI) check documents on the roads leading to the forestry enterprise. On the territory of the yacht club on the river. Rannapungerja (flows into Lake Peipsi), the head of the recreation areas at the Kohtla-Järve Executive Committee [Agu Väarem] says (sync. And behind the scenes in Estonian) that polluted water is the result of human activity, and the state of those around us depends only on the person rivers and lakes.