Для решения задачи оценки внешней нагрузки на российскую часть р. Иртыш со стороны водосбора использована модель ILLM, учитывающая вклад точечных и рассредоточенных источников в формирование нагрузки. Модель позволяет рассчитывать вынос примесей с водосбора с учетом влияния гидрологических факторов и удержания химических веществ водосбором и его гидрографической сетью. Для обеспечения модели необходимой входной информацией выполнена классификация подстилающей поверхности с использованием снимков со спутников PROBA-V и Sentinel-2. Собраны и проанализированы данные о содержании биогенных элементов (N и P) и микроэлементов (Cu и Zn) в природных (почвенных и речных) водах изучаемой территории. На основе обработки материалов о деятельности более 800 сельскохозяйственных предприятий оценено поголовье скота, внесение органических и минеральных удобрений, а также рассчитано поступление общего азота и общего фосфора в гидрографическую сеть. По результатам моделирования выполнена оценка внешней нагрузки (включающей диффузную составляющую) биогенными элементами (азотом и фосфором) и металлами (медью и цинком) как для всей российской части бассейна р. Иртыш, так и для семи его подбассейнов, в том числе для рек Тобол, Ишим, Омь и Конда. Оценен вклад трансграничной нагрузки на вынос рассматриваемых химических веществ в замыкающих створах трансграничных рек. Показано, что соотношение вклада различных составляющих внешней нагрузки в вынос изменяется в зависимости от водности года. To solve the problem of assessing the external load on the Russian part of the Irtysh River from the catchment, the ILLM model was used. It takes into account the contribution of point and diffuse sources to the formation of the load and makes it possible to calculate the removal of impurities from the catchment. The model takes into consideration the influence of hydrological factors and chemical retention by the catchment and its hydrographic network. In order to provide the model with the necessary input information, classification of the underlying surface types has been performed using PROBA-V and Sentinel-2 satellite images. Data on the content of nutrients (N and P) and trace elements (Cu and Zn) in soil and river waters of the studied territory were collected and analyzed. Based on the processing of materials on the activities of more than 800 agricultural enterprises, the number of livestock, and organic and mineral fertilizer inputs were estimated, and the total nitrogen and total phosphorus inputs to the hydrographic network were calculated. The external load (including the diffusive component) of nutrients (nitrogen and phosphorus) and metals (copper and zinc) was assessed for both the entire Russian part of the Irtysh basin and for seven of its sub-basins, including the Tobol, Ishim, Om and Konda rivers. According to the calculation results, the contribution of the transboundary load to the outflow of the considered chemicals in the outlet sections of the transboundary rivers was evaluated. It is shown that the ratio of the contribution of different components of the external load to the outflow varies depending on the water content of a year.

The ILLM model was used to solve the problem of assessing the external load on the Russian part of the Irtysh River from the catchment. It takes into account the contribution of point and diffuse sources to the formation of the load and makes it possible to calculate the removal of impurities from the catchment. The model takes into consideration the influence of hydrological factors and chemical retention by the catchment and its hydrographic network. In order to provide the model with the necessary input information, the underlying surface types have been classified using PROBA-V and Sentinel-2 satellite images. Data on the content of nutrients (N and P) and trace elements (Cu and Zn) in soil and river waters of the studied territory have been collected and analyzed. Based on the processing of materials on the activities of more than 800 agricultural enterprises, the number of livestock and organic and mineral fertilizer inputs are estimated and the total nitrogen and total phosphorus inputs to the hydrographic network are calculated. The external load (including the diffusive component) of nutrients (nitrogen and phosphorus) and metals (copper and zinc) is assessed for both the entire Russian part of the Irtysh basin and for seven of its subbasins, including the Tobol, Ishim, Om, and Konda rivers. According to the results, the contribution of the transboundary load to the outflow of the considered chemicals in the outlet sections of the transboundary rivers is evaluated. It is shown that the ratio of the contribution of different components of the external load to the outflow varies depending on the water content of a year.

The article is aimed at developing and testing a methodology for collecting information to calculate the diffuse input of nitrogen and phosphorus from agricultural land to water bodies using the IEEP model due to the lack of detailed information on individual agricultural enterprises in relation to the conditions of the Lake Onego catchment. The methodology enables obtaining comprehensive information about agricultural objects, taking into account their impact on the environment. The methodology is based on the use of spatial analysis and GIS technologies to calculate the load more accurately, considering the characteristics of agricultural activities and distance to water bodies. Thus, one can perform a comprehensive analysis in relation to the spatial parameters of the environment. The methodology provides the calculation of the volume and composition of manure, considering systems for its storage, processing and application, as well as assessment of the nutrients migration parameters depending on the location of agricultural land. Based on the results of the agricultural objects analysis in the GIS, in view of available information, the number of animals and poultry, the production of manure, as well as the number of manure storage facilities at the enterprise, the average application rates of nitrogen and phosphorus with organic fertilizers are quantified. The proposed methodology was implemented in the Lake Onego catchment to prepare data for calculating the nitrogen and phosphorus diffuse load in 2010 and 2021. The IEEP methodology helped to assess and compare nutrient input from agriculture to the Lake Onego water objects in 2010 and 2021

Data on the main sources of nutrient load on Lake Onego watershed were collected along with the available data of field observations of nitrogen and phosphorus inflow into the lake. Mathematical modeling was used to assess the agricultural load onto the lake and its possible decrease due to the introduction of the best available techniques to agricultural production. It was shown that a decrease in agricultural load after the introduction of best available technologies is unlikely to have a significant effect on the ecological conditions of Lake Onego. Simulation calculations were carried out to evaluate an increase in the input of N and P into the lake from fish farms on the watershed under the condition that the rate of fish farming growth in the water bodies in the basin will remain the same up to the year of 2050. It is shown that, in this case, an increase in nutrient load onto the lake by 3.9

The study aimed to assess the possible reduction of the nutrient load and nitrogen and phosphorus losses from the Russian part of the Irtysh River catchment, one of our country’s largest transboundary rivers, by implementing the best available techniques (BAT) in agricultural production. The Institute of Limnology Load Model (ILLM) mathematical model of nutrient load on the river watershed was used to solve the problem. Information on the primary sources of the nutrient load was collected for the entire Russian part of the Irtysh River catchment and tributaries catchments: Om, Ishim, Tobol, and Konda rivers. Agricultural activity of more than 800 enterprises concentrated mainly in the southern part of the Russian basin was analyzed. The calculations show that the most significant reduction of agricultural nutrient load due to BAT implementation is achieved in the Russian part of the catchment area of the Tobol River (31% for nitrogen and 25% for phosphorus from the total load on the catchment). The nutrient load can be reduced by 23% of nitrogen and 18% of phosphorus due to BAT implementation from the entire catchment of the Irtysh River (Russian part), which will lead to a corresponding reduction in a nutrient run-off by 13% of nitrogen and 4% of phosphorus. Therefore, a significant decrease in nutrient transport by river flow cannot be expected. However, it is essential to confirm the possibility of nutrient load reduction through the implementation of BAT, aiming at the transition to modern production technologies by minimizing the impact on the environment and maintaining the economic efficiency of agricultural production.

Agricultural intensification leads to higher diffuse environmental pollution. Successful pollution control requires the continuous monitoring of farming activities, reliable baseline data, and tested computational models for the quantitative assessment of diffuse loads. The study aimed to quantify the diffuse inputs of manure nitrogen (N) and phosphorus (P) to the marine environment from large livestock farms and to identify the lowering effect of the best available techniques of manure/organic fertiliser handling. The study area was the Leningrad and Kaliningrad regions, found in the Russian part of the Baltic Sea catchment area. The total diffuse load in 2017 was estimated by the Russian and Belarus methodologies based on the calculations of the livestock density and the total field application of nitrogen and phosphorus with organic fertilisers. In the Leningrad Region, it was 4571.53 t N year−1 and 280.01 t P year−1; in the Kaliningrad Region—6132.48 t N year−1 and 372.32 t P year−1. The introduction of relevant best available techniques and the supply of all farms with waterproof manure storages and pads could reduce the diffuse load on the catchment in the Leningrad region by 1078.07 t N year−1 and 55.5 t P year−1 and in the Kaliningrad Region—by 1060.43 t N year−1 and 40.5 t P year−1. Such a reduction would provide a marked contribution to fulfilling the nutrient input ceilings set for the Russian Federation under the Helsinki Commission (HELCOM) Baltic Sea Action Plan.

Представлены результаты оценки фосфорной нагрузки на крупнейший европейский трансграничный водоем — Чудско-Псковское озеро в условиях минимальной проточности, характерной для маловодного периода 2010—2015 гг. Расчет внешней фосфорной нагрузки выполнен с использованием модели формирования биогенной нагрузки ILLM (Institute of Limnology Load Model), разработанной в Институте озероведения РАН и учитывающей вклад точечных и рассредоточенных источников. Вынос с сельскохозяйственных полей определялся исходя из содержания Р в пахотном слое почвы, дозы внесения минеральных и органических удобрений на поля и их усвоения сельхозкультурами. Для оценки современных значений площадей различных типов подстилающей поверхности, являющихся входными данными для моделирования, применялись данные космической съемки, находящиеся в режиме свободного доступа. Расчет внутренней фосфорной нагрузки на озерную экосистему за счет вторичного поступления фосфора из донных отложений выполнен с привлечением данных натурных наблюдений на акватории. Использована методика, разработанная в Институте озероведения РАН и основанная на балансовых оценках основных потоков фосфора (седиментации, захоронения и поступления из донных отложений в воду) в пограничной зоне «вода–дно». Показано, что в условиях рассмотренного маловодного периода внутренняя фосфорная нагрузка превосходит внешнюю, что негативно сказывается на эвтрофировании озера.

The study aimed to compare the calculated and directly measured total nitrogen input from farm fields into the water bodies exposed to crop-growing practices and livestock facilities in place. The study applied an IEEP-designed model for diffuse loading calculation. The study area was a dairy farm with 2100 head of animals and 2000 ha of fields, located in the Luga River catchment, the Leningrad Region. 40 ha were selected for elementary plots. The geoinformation systems served to identify the watercourses from the fields into the river and the water sampling points for measuring the concentration of total nitrogen and nitrate nitrogen. The calculations by the model showed the average specific nitrogen runoff from the fields was 44.96 kg ha(-1). The monitoring data analysis revealed the Kjeldahl total nitrogen content in the water varying from 1.4 to 3.1 mg (dm(3))(-1), and the nitrate nitrogen content-from 2.28 to 9.1 mg (dm(3))(-1) depending on the season and precipitation. The calculation of the monitoring data demonstrated the inputs of total nitrogen from farm fields into watercourses ranging from 35.24 to 36.84 kg ha(-1). Comparing the nitrogen runoff data, calculated by the model and directly measured by the nitrogen concentrations in watercourses, disclosed a discrepancy in the study territories from 17 to 21% explained by several factors. In general, the study demonstrated sufficient convergence, with certain assumptions, of two methods for identifying the nitrogen inputs into water bodies. The direct measurements method is hard to apply to large catchments. The method of IEEP is designed mostly for analysing the nutrient inputs from vast territories to form a comprehensive overview of current and forecast situations without taking into account specific places with possible violations. This method focuses on the elaboration and introduction of strategic measures for environmentally sustainable rural development.

Estimate is made for the possible reduction of nutrient export from the drainage basins of tributaries of the Kuibyshev Reservoir through the introduction of the best available technologies of agricultural production. The activity of more than eight hundreds of agricultural enterprises in the reservoir drainage basin was analyzed. Different types of underlying surface were classified with the use of space photographs. Mathematical simulation was used to calculate first the distributed agricultural nitrogen and phosphorus load onto the drainage basin and next the export of nutrients with river runoff into the reservoir either under current conditions or after the introduction of the best available technologies (BAT) to agricultural production. The simulations show that, under the conditions of medium water abundance, the total export from the drainage basins of the Sviyaga, Kazanka, Mesha, and Bol’shoi Cheremshan will decrease by about 367 t N/year and 12 t P/year after the introduction of BAT into the agricultural practice. The application of nitrogen and phosphorus into the soil as components of mineral and organic fertilizers in most administrative territories of the region under consideration was found to be less than the nutrient demand of agricultural crops, resulting in the gradual depletion of such elements in soils and a decrease in the risk of their migration into water bodies.

Main sources of pollution of the river Novaya, one of the most ecologically unfavorable water bodies in St. Petersburg, have been revealed on the basis of hydrological, hydrochemical and geochemical data. The river lost natural water supply and its length decreased by 4 times after the runoff from the upper part of catchment was redirected to the river Dudergofka during the construction of the Pulkovo Airport several decades ago. Currently, the river is a drainage system of agricultural territory, supplying a system of six connected ponds at urban area. The main ecological problem of the aquatic system under study has been found to be nutrient and organic pollution. Main reason of pollution is intensive agricultural activity at the catchment area. As a result, a huge amount of phosphorus, nitrogen and organic substances enters the hydrographic network. Low flow rate of the water system makes worse the development of negative processes in the ecosystem. The main polluter is a livestock enterprise located in the upper part of the catchment area. It discharges wastewater into the drainage system in the catchment area and manures agricultural fields directly adjacent to the riverbed. In accordance with the evaluation criteria of the degree of surface waters chemical pollution, approved by the Ministry of Natural Resources of the Russian Federation, the situation is assessed as extreme in the aquatic system, and at some sites - as a zone of ecological disaster by a number of parameters. No contamination of water and bottom sediments, as well as soils in the catchment area with priority organic pollutants previously entering from the airport territory was detected. Nutrient loading on the aquatic system of the catchment area from the agricultural enterprise has been calculated. It has been assessed that the use of the best available technologies for agricultural activity could reduce the phosphorus load by 9 % and the nitrogen load by 28 %. Currently, the calculated concentration of total phosphorus in the drainage system in the catchment area is 4 times higher than the hyper eutrophic state limit. An improvement in the ecological situation can be achieved by optimizing agricultural activity in the catchment area, periodical removal of some nutrients and organic substances by mowing macrophytes in the swampy floodplain area, establishing a coastal protective zone and increasing the flow rate as a result of the return of runoff from the upper part of the river catchment to the former course

Introduction of new intensive animal housing practices results in the increased amount of manure produced with a higher share of slurry. Reducing nitrogen emissions from the agricultural activities into the environment is one of the priorities of agroecology. In 2016, ammonia losses to the atmosphere from livestock farming from the territory of the Russian Federation amounted to about 677,000 tons. One of the solutions to this problem is implementation of slurry acidification techniques by adding concentrated sulfuric acid. In the study the prerequisites for application of these techniques in large-scale cattle and pig-rearing complexes in the subjects of the Russian Federation located within the boundaries of the Baltic Sea catchment area were considered; the main features of the Russian legislation related to the treatment of slurry were analysed. In addition, a series of experiments was conducted with the samples of slurry from the Russian farms for preliminary assessment of sulfuric acid demand. With the mathematical model created in the framework of the EU project "Baltic Slurry Acidification", the economic efficiency of slurry acidification techniques on a pilot farm in Russia was determined. The work done showed that the region under consideration had a significant potential for slurry acidification: out of 11.8 million tons of manure produced in the region, 7.4 million tons could potentially be used for this purpose. Slurry acidification techniques have both pros and cons associated, primarily, with the increased risks of emergencies when handling the particularly dangerous substances, sulfuric acid included.

The present level of external nutrient load and its separate parts on the Kuibyshev reservoir — the largest one on the Eurasian continent, was estimated. The mathematic model for calculating mean annual input of nitrogen and phosphorus from river drainage areas of non-homogeneous structure, and load on water bodies was developed. The main components of the load are the nonpoint nutrient emission by the underlying surface which is currently not affected by agricultural impact, the load generated by agricultural activity, discharges of pollutants from point sources into the hydrographic network of the catchment area and directly into the water-receiving reservoir, and the mass exchange with the atmosphere. The model includes calculating the retention of chemicals by catchments and by their hydrographic network. The model was calibrated against the data of State monitoring for the pilot areas: the catchment area of the Kazanka river (the left bank tributary) and the Sviyaga (the right bank tributary). The nutrient load generated by discharges from point sources of pollution was estimated using statistical reporting data. The values of atmospheric deposition of nitrogen and phosphorus on the surface of the study catchments were calculated using the data of field studies on the chemical composition of deposits. It is shown that implementation of the best available technologies into agricultural practice will not lead to any significant reduction in the nutrient load on the reservoir, because in recent years across most of the study area the rates of application of nutrients with organic and mineral fertilizers have been lower than the average removal of nitrogen and phosphorus with the harvested crops. An approximate estimation of nutrient load on the Kuibyshev reservoir was carried out for the left and the right bank sides of the catchment area. The background (natural) and diffuse (anthropogenic) components of the load are identified

2 Институт инженерных и агроэкологических проблем сельскохозяйственного производства Представлены результаты расчетов современного уровня внешней и внутренней фосфорной нагрузки на систему Дудергофских озер, расположенных на территории Санкт-Петербурга.Оценка внешней нагрузки выполнена с использованием модели ILLM в сочетании с данными спутниковой съемки водосбора, оценка внутренней нагрузки -на основе данных натурных наблюдений.Установлено, что в условиях средней водности на поверхность водосбора поступает 2,621 т Р/год, водосбором и его гидрографической сетью удерживается 1,627 т Р/год, нагрузка на акваторию озер с водосбора составляет 0,994 т Р/год.При этом внешняя нагрузка на озера системы пропорциональна их водосборным площадям.Внутренняя нагрузка оценивается в

In 2017 a field study of water bodies in Nevel and Usvyatsky Districts of Pskov Region was aimed to give qualitative and quantity estimation of the impact of local large-scale pig enterprises on the status of water bodies in the Western Dvina river basin. Water samples were taken and the flow was measured on the vulnerable areas and outside the farm impact area in accordance with an elaborated programme and methods of field measurements. Soil samples were collected from the fields, where liquid pig manure was applied. The results showed that on the local level, in the vicinity of these fields, the water bodies featured high levels of main manure pollution indicators - ammonium nitrogen and phosphorous. The concentration of ammonium varied from 4.4 to 32.7 mg.l(-1) at these points that was several hundred times higher than that in water bodies in natural areas; the concentration of dissolved phosphorus varied from 0.11 to 0.23 mg.l(-1) that was several times higher than the background values. The concentration of these elements was dropping down to the background level with the distance from the fields as the result of self-purification and dilution processes owing to natural conditions, associated mainly with the presence of wetlands.

Agricultural production is one of the main sources of nitrogen and phosphorous inputs to the water bodies. Quantifying nutrient input from agriculture is needed both to develop effective environmental measures and to justify the technologies to be applied with due account for local natural and climatic conditions. Several related national studies have been conducted since 2015. Institute for Engineering and Environmental Problems in Agricultural Production (IEEP) methodology was used for this purpose. It determines the nitrogen and phosphorus content in the arable layer, including N and P amounts applied with mineral and organic fertilisers. Such factors as soil type and texture, the distance to the water bodies and the land use structure are used to estimate the nutrient input to the water bodies. In addition, the consistency of manure handling technologies with Best Available Techniques (BAT) principles is taken into account through introduction of relevant coefficients. Calculation results according to IEEP methodology were used in the follow-up general assessment of the nutrient load on the water bodies from different sources with the use of Institute of Limnology Load Model. Satisfactory correspondence between the assessment results and the values calculated using the monitoring data confirmed the adequacy of the above assessment procedure. Following its outcomes, the nutrient reduction potential of agricultural sources is approximately 10–20 %.

Improvement of the mathematical model of nutrient load in the catchment area was carried out. Now the model allows to evaluate changes in the removal of nutrients, depending on the optimization of agricultural production. Quotas to reduce the nutrient load between different parts of the catchment area of the Russian Gulf of Finland using the recommendations of the HELCOM Baltic Sea Action Plan are promulgated. Refs 21. Figs 1. Tables 3.