The Field Survey Findings and Recommendations on the Dnipro Basin Transboundary Monitoring System Design

Up one level

7. THE FIELD SURVEY FINDINGS AND RECOMMENDATIONS ON THE DNIPRO BASIN TRANSBOUNDARY MONITORING SYSTEM DESIGN

 

Findings. As a result of the 2000-2001 international field surveys on assessment of environmental situation in the transboundary sections of the Dnipro River Basin, new original data were collected to provide a picture of the existing river ecosystem status. Landscape diversity assessment surveys and review of the existing state of the natural reserves and protected areas located in the transboundary sections of the Dnipro River Basin provided a basis for identification of issues and problems relating to conservation of landscape and biological diversity in these areas.

 

The surveys have revealed that the floodplains of the Pripyat, Ubort and Stvyga Rivers have been severely damaged and urgent actions are needed to protect what is left of their landscape diversity.

 

Review of the existing state of the natural reserves and protected areas in the transboundary sections of the Dnipro River Basin has shown that their landscape and biological diversity conservation capacity is inadequate, and they are not able of being used as a reference basis for the purposes of ambient water quality monitoring.

 

In terms of ecological/sanitary criteria, the examined water bodies can be mainly described as moderately polluted or dirty, corresponding to Water Quality Categories 5-7.

 

The prescribed MAC limits for fishery water use were found to have been exceeded in the majority of water bodies for a range of parameters (COD, BOD₅, sulphates, ammonium and nitrites).

 

The field survey results confirmed that metal concentrations were relatively high in the transboundary river sections of the Dnipro Basin, where the fishery MAC limits for metals were exceeded in all water samples.

 

All bottom sediment samples were found to contain iron and manganese at considerable concentrations.

 

MAC limits for zinc, copper, lead and arsenic were exceeded in fish samples, as well as the interim sanitary guideline levels for iron, chromium and nickel.

 

Excessive concentrations of metals and arsenic in the water, bottom sediment and aquatic biota samples from the transboundary sections of the Dnipro Basin indicate that these media have accumulated the above mentioned substances at considerable quantities.

 

Concentrations of zinc, copper, nickel and mercury in all examined water bodies were found to be excessive only in terms of the MAC limits for fishery water use.

 

During the spring field survey, only two water samples (from the Nobel Lake and Seim River) were found to contain oil products at concentrations not exceeding the MAC limit set for fishery water use. A mid-stream sample taken from the mouth section of the Dnipro River contained oil products at the level of 1.1 mg/dm³, i.e. 3.7 times higher than MAC limit set for potable and recreational water uses.

 

Analytical results indicate that HCCH, n,n'-DDT and its metabolites were the predominate organochlorines found in the transboundary river water samples. a-HCCH was detected in 72% of all water samples at the levels ranging from 0.003 to 0.111 mg/dm³. γ-HCCH concentrations in water samples ranged from 0.012 to 0.018 mg/kg. The n,n'-DDT levels were found to be below our detection limits in most of water samples, whereas n,n'-DDE was detected in 47% of water samples at concentrations ranging from 0.007 to 0.026 mg/dm³. The highest levels of organochlorine pesticides were found in water samples taken from the Nobel Lake, Kyiv reservoir, Seim River and Desna River section between the Kamen village and Chernigov.

 

The measured concentrations of DDT and a,b,g-HCCH in the samples from the Seim and Psyol Rivers were within the existing guideline limits.

 

The g-HCCH concentrations ranged from 0.012 to 0.017 mg/dm³, and the level of n,n'-DDE was 0.020 mg/dm³. Water samples taken during the field surveys were found to contain no herbicides (treflane, harness and synthetic pyrethroids) at the levels detectable by the standard techniques. Only 2,4-D herbicide was detected at concentrations ranging from 2.1 to 2.4 mg/dm³ in water samples taken from the Desna and Sudost Rivers, and the mouth section of the Dnipro River itself. Organochlorine pesticides were present in the bottom sediment samples at the levels reflecting their global dispersion pattern. Moreover, 38% of the bottom sediment samples were found to contain treflane.

 

Higher concentrations of pesticides were also registered in water samples from the Rivers of Sozh, Ipout, Styr, Slovechna, Pripyat, Seim and Dnipro itself.

 

Organochlorine pesticides were detected in all fish samples. Fish were found to have accumulated toxic substances at the considerably higher levels than their ambient concentrations in water. A clear organochlorine pesticide contamination pattern emerged from analyses of freshwater fish species (pike, perch, pike perch, catfish, ide, bream, and rudd), where the highest contamination levels were detected in liver, with generally low concentrations being present in fish muscles. A general trend of higher toxic contamination levels in the predator fish samples (pike, perch, and pike-perch) compared to the benthophage fish suggests that they could be recommended as the test organisms for the purposes of ecotoxicological monitoring.

 

The major organochlorine pesticides detected in all fish samples were a- and g-HCCH, n,n'-DDT, n,n'-DDE and n,n'-DDD, and heptachlor. Accumulated pesticide metabolites, in particular n,n'-DDE, were detected in fish muscles and organs, indicating major metabolic changes that have occurred in fish since the initial exposure to contamination. a- and b-HCCH, n,n'-DDT and its metabolites n,n'-DDE and n,n'-DDD were detected in shellfish samples. There appear to be differences among water bodies in terms of pesticide accumulation levels in shellfish.

 

The highest bacterial contamination levels were recorded in the transboundary sections of the Pripyat River tributaries (the Goryn, Styr and Stvyga Rivers) where the Escherichia coli numbers during the autumn field survey were 10,980,000 cells/l, 3,200,000 cells/l and 600,000 cells/l, respectively; and the recorded Salmonella numbers were 102 cells/ml, 70 cells/ml and 34 cells/ml, respectively.

 

The number of the lactopositive Escherichia coli in samples from the Snov and Sudost Rivers was found to have exceeded the MAC limits for recreational/domestic water uses by 1.2 time.

 

The results of microbiological analyses indicated that samples collected from the transboundary section of the Desna River were characterised by the lowest quantities of bacterial plankton and heterotrophic microorganisms. During the Autumn 2000 field survey, the recorded quantities of bacterial plankton and heterotrophic bacteria at the Belorussian/Russian border section were 1.87 million cells/ml and 1,600 cells/l, respectively. Bacteria species active on oil products and surfactants were detected in minor quantities. The recorded Escherichia coli were near 60,000 cells/l. The 3.6-fold increase in quantity of heterotrophic organisms was recorded for this section during the spring field survey, attributed to pollution carried from the adjacent country territory during the spring high-flow period.

 

Also, samples taken from this river section during the spring field survey had higher quantities of bacterial plankton (by 1.4 times), heteroptrophic bacteria (by 2.8 times) and Escherichia coli (by 2.2 times).

 

In terms of bacterial pollution levels, the water of the Dnipro River can be described as ‘moderately polluted’. The field survey results illustrate the need for integrated environment protection actions to be undertaken in the Dnipro Basin.

 

The highest bacterial contamination levels were recorded at the transboundary section of the Vorskla River (downstream of the Lugovoe village). Wastewater discharges from the local dairy and municipal wastewater treatment plant have affected the hydrobiological regime of the river. The recorded quantities of bacterial plankton and heterotrophic organisms for this section of the Vorskla River were 4.73 million cells/ml and 184,000 cells/ml, respectively. The quantities of bacteria active on oil products and surfactants were also relatively high: 1,800 cells/ml and 4,430 cells/ml, respectively.

 

In general, 473 phytoplankton species were recorded in the Dnipro Basin, with 321 species found in the transboundary sections of the Basin (see Annex, Table П.1). The phytoplankton diversity was dominated by Bacillariophyta (39.8%) and Chlorophyta (34.3%), with other groups represented by Euglenophyta (7.8%), Cyanophyta and Chrysophyta (6.3%), Xanthophyta (3.2%), Dinophyta (2.1%), and Сryptophyta (0.2%).

 

Phytoplankton community structure data for the transboundary sections of the Dnipro Basin rivers indicate that their water can be characterised as ‘moderately polluted’ by organic substances. Saprobiological index values varied within a range of 1.63 to 2.63 for the indicator phytoplankton species. The highest organic pollution levels were recorded for the transboundary sections of the Desna, Seim, Goryn, Ubort and Stvyga Rivers.

 

Chlorophyll a can be used as a criterion for classification of water bodies in terms of their trophic state. Also, the chlorophyll content might be a useful tool for preliminary assessment of the phytoplankton community structure. Review of the field survey results shows that correct and credible conclusions on the trophic state of water bodies on the basis of the chlorophyll content data can only be made if the seasonal changes in concentrations of this pigment are monitored over a year. Therefore a conclusion on the trophic state of a water body made on the basis of a single-time measurement of the concentration of this pigment should be regarded as preliminary.

 

The dominating zooplankton species were juvenile Copepoda species, Asplanchna priodonta, Euchlanis dilatata, Daphnia cucullata, Bosmina longirostris, and Chydorus sphaericus. In terms of ecological groups, the zooplankton communities of the Pripyat River and its tributaries were dominated by pelagic species, represented by juvenile Copepoda species, Bosmina longirostris, Daphnia cucullata, Asplanchna priodonta etc. In the Slovechna River and Stokhod branch, the phytophilous and riparian phytophilous communities were typical, dominated by Ceriodaphnia quadrangula (the Stokhod branch) and Trichocerca longiseta (the Slovechna River). In the Lva River, the bottom/phytophilous species were present, dominated by Chydorus sphaericus. Zooplankton communities of the Ubort River were also dominated by the bottom/phytophilous species during the autumn field survey, while none of them were found during the spring survey.

 

The zooplankton trophic structure was relatively diverse in the Dnipro Basin watercourses, being a positive indication of the adequate capacity for utilisation of organic substances.

 

The field survey results on community structure and saprobiological indices of zooplankton demonstrated that pollution levels were relatively low in the rivers, with the water quality in the Pripyat River Basin being mainly affected by the factors of natural origin, whereas the anthropogenic factors play a major role for the Dnipro River itself and its left-bank tributaries.

 

Zoobenthos is an important indicator of the aquatic ecosystem state, and there appeared to be significant differences among the transboundary sections of the Dnipro Basin. In the Pripyat River Basin, benthic fauna development is mainly affected by natural factors (soil properties and hydrological regime), while the effect of anthropogenic factors is minor. As a result, biotic and diversity indices vary in a wide range among the rivers. Only in the Goryn River, the state of benthic communities suggests significant inputs of organic pollution from local sources.

 

In the Desna River and its tributaries, the benthic community development has been affected by the organic pollution loads increasing in the downstream direction, which can be attributed to the effects of intensive agricultural activities in the immediate proximity to the river.

 

The ecosystems of the Psyol and Vorskla Rivers have been modified as a result of damming and flow regulation activities, featuring a greater variety of biotopes sustaining diverse benthic fauna.

 

Interpretation of zoobenthos diversity and abundance indices derived for the transboundary sections of the Dnipro Basin suggests that anthropogenic factors have not caused persistent effects on the state of the ecosystems, being of rather discrete nature.

 

The field survey results and specialist literature data demonstrated considerable diversity (up to 200 species) of parasites living in or on fish, shellfish and crayfish species inhabiting the transboundary sections of the Dnipro Basin. The parasitic fauna includes species capable of causing disease and death of fish (Trypanosome, Microsporidia, Diplostomuma, and Ligula). Moreover, the following pathogenic species were registered in some instances: Opisthorchis felineus, Metagonimus yokogawai, Pseudamphistomum truncatum, Metorchis albisus, Mesorchis denticulatus, Apophallus muehlingi, and Diphyllobothrium latum.

 

Small rivers and floodplain lakes are considered to be the major reproduction grounds of pathogenic and parasitic fauna in the transboundary sections of the Dnipro Basin, wherefrom its spreads downstream.

 

The parasitic fauna variety was found to be the richest in fish from the Kyiv reservoir and the Pripyat River estuary. High levels of fish infestation by Trematoda and Cestoda are considered to be the classical example of the disturbed biological equilibrium as a result of river flow regulation and reservoir construction.

 

The river water samples analysed for toxicity in the field conditions were found to contain no toxic substances at detectable levels, whereas chronic toxic effects were registered in the laboratory conditions. No toxic substances were detected in the bottom sediment samples. Water samples from the Dnipro River Basin were analysed for toxicity with a set of animal and plant bioassays, and no toxic responses were registered. In the test on plant bioassay, lower plant growth rates in the unconcentrated water samples were caused by a shortage of nutrients rather than presence of toxic substances. Bioassays on Daphnia detected no toxic effects in virtually all samples, whereas nearly half of concentrated samples produced toxic effects on Hydra.

 

Radionuclides. The ⁴⁰K activity concentrations in the majority of the Dnipro tributaries were found to have stabilised at the levels ranging from 0.02 to 0.35 Bq/l.

 

The ⁴⁰К activity concentrations in the upper tributaries of the Dnipro River were lower than in its downstream tributaries, attributed to lower mineralisation levels in the water of the upstream tributaries of the Dnipro River.

 

The measured ⁴⁰К contents in the bottom sediments correlated well with data on its concentrations in soils, suggesting that the major inputs of this radionuclide are associated with the surface runoff and groundwater sources.

 

Generally, the specific activity of ⁴⁰К in bottom sediments increases as one moves downstream, where the bottom sediment samples from the downstream tributaries had slightly higher levels of the ⁴⁰К specific activity than the samples from the Dnipro reservoirs, attributed to higher dilution rates and microorganism abundance levels in the water of the reservoirs.

 

The highest levels of the total beta-radioactivity and potassium-40 contents were registered in the sandy bottom sediment samples from the Sozh River, whereas the bottom sediments from the Slovechna and Ubort Rivers had the lowest levels of the total beta-radioactivity and potassium-40 specific activity.

It should be noted that the highest radioactivity levels were registered during the spring flood period, which can be attributed to higher inputs carried with surface runoff from territories contaminated as a result of the Chernobyl accident.

 

The measured ¹³⁷Cs concentrations in the bottom sediments of the Middle and Lower Dnipro tributaries varied within a range of 5-46 Bq/kg, whereas this range was wider in the bottom sediment samples from the Upper Dnipro Basin (2.3-100 Bq/kg), attributed to the immediate proximity of the Chernobyl Nuclear Plant and ‘spotty’ distribution of radioactive contamination. These levels were detected in the air-dried bottom sediment samples, and it is assumed that the cesium-137 concentrations in the natural wet samples would be lower by about 2-5 times. The highest concentration of cesium-137 was detected in the bottom sediment sample from the Ipout River.

 

The existing radioecological situation in the Dnipro River Basin can be described as one of considerably uneven distribution of contamination, suggesting strong local sources of anthropogenic nature.

 

Tritium is a major radioactive component of effluent generated by the nuclear power facilities, being regarded as a dangerous long-lived radionuclide capable of spreading far beyond the immediate impact area of a source.

 

Ambient tritium level in the locations of nuclear power facilities is the most useful and efficient indicator for the environmental safety monitoring and assessment of these operations.

 

Tritium concentrations in water were generally below or slightly above the detection limits of the measurement techniques involved, i.e. up to 3.4 Bq/l. The only exception was water sample from the Styr River where the tritium concentration was at 7.5 Bq/l, suggesting that the Rivne Nuclear Power Plant as a local source there made a larger contribution than in other parts of the Basin.

 

Radionuclide distribution pattern in the bottom sediment samples was similar to that of water samples, although more pronounced in terms of reflecting the overall picture of radionuclide contamination as a result of the Chernobyl accident. Maximum concentrations of ¹³⁷Cs were registered in the Pripyat River tributaries (up to 435.0 Bq/l), the Upper Dnipro tributaries (146.0 Bq/l), the Kyiv reservoir being the major trap for the Chernobyl-related radionuclide contamination (up to 263.0 Bq/l) and the Snov River (102,0 Бк/л. The ⁹⁰Sr levels in the bottom sediments correlated well with data on the ¹³⁷Cs concentrations, suggesting exposure to localised sources of the Chernobyl-related radioactive contamination.

 

The highest level of strontium-90 was registered in the bottom sediment samples from the Pripyat River within the 30-km Chernobyl zone (4.8 Bq/kg of dry sample mass), whereas a sample from the Ubort River had the lowest level (0.27 Bq/kg).

 

Bivalve mollusks act as natural filters, contributing significantly to the river self-purification processes. The data on radionuclide contents in bivalve mollusks sampled in the Pripyat River Basin indicate that such species as Dreissena and Unito pictorum, being the most powerful biological filters among the freshwater macrozoobentic community, had the highest values of accumulation factors for ⁹⁰Sr and ¹³⁷Cs (over 1,100 for ⁹⁰Sr in Dreissena, and near 500 for ¹³⁷Cs in Unito pictorum).

 

The tritium levels varied within a range of 2.3–7.5 Bq/kg, and the highest concentration was registered in a sample from the Styr River receiving effluent discharges from the Rivne NPP.

 

Transboundary pollution monitoring in the Dnipro River Basin. It is commonly recognised that the design of a water resource monitoring system has to be tailored to the information needs and requirements of the basinwide environmental management system. From this perspective, the transboundary pollution monitoring system should be able to provide answers to the following questions:

- What amount of polluting substances is carried with the river flow through the selected transboundary monitoring stations?

- Is there any threat of acute deterioration of water quality as a result of accidental spills, natural disasters etc?

 

That said, such monitoring system should also be capable of serving the other traditional objectives of water quality monitoring, like information support for periodical assessment of short-term and long-term trends in water quality.

 

Clearly, a properly planned and designed monitoring system should be capable of meeting these information needs at reasonable cost, ideally kept at a minimum level. This key limitation provides an impetus to seek solutions as to how the information needs could be met at acceptable cost.

 

The primary objective of the 2000-2001 field surveys was to set up the data base for assessment of the existing transboundary pollution loads. Therefore the recommendations presented below are mainly focussed on this specific objective of transboundary pollution monitoring.

 

The existing water quality monitoring network in the Dnipro Basin is by no means adequate for representative assessment of transboundary pollution loads and inter-governmental decision-making on the environmental rehabilitation actions in the Basin. Therefore additional monitoring stations need to be established in the cross-border sections, to be operated on the basis of the unified transboundary monitoring methodology.

 

In addition to the existing stationary monitoring network, the following sites are proposed as the transboundary pollution monitoring locations:

- the Styr River (the Ukrainian/Belorussian border, 75 km to the mouth);

- the Lva River (the Ukrainian/Belorussian border, 84 km to the mouth);

- the Stvyga River (the Ukrainian/Belorussian border, 126 km to the mouth);

- the Ubort River (the Ukrainian/Belorussian border, 120 km to the mouth);

- the Dnipro River (the Russian/Belorussian border, 1,653 km to the mouth);

- the Ipout River (the Russian/Belorussian border, 32 km to the mouth).

 

Moreover, it would be useful to establish a stationary monitoring network to cover two-three catchments that have not been subjected to impacts of human activities (e.g., within the natural reserve areas).

 

At the first stage of the transboundary pollution monitoring system development, the effort should be focussed on the following major watercourses of the Dnipro basin: the Dnipro River itself (the Russian/Belorussian border; the Belorussian/Russian border; and the estuary), the Pripyat River (the Belorussian/Ukrainian border), and the Desna River (the Russian/Belorussian border). The existing flow and water quality measurement sites at these sections could be used as a basis for development of the transboundary pollution monitoring network.

 

For these sites, a special transboundary pollution monitoring regime should be developed and established at a very early stage. It is clear that special study is required to define this monitoring regime, although some preliminary recommendations may be made on the basis of the field survey findings and international practice. The recommendations are discussed below.

 

The list of the monitored variables should be expanded by including the following mandatory parameters:

- mineralisation, macrocomponents;

- dissolved oxygen;

- BOD₅;

- COD;

- nutrients (nitrogen group and phosphorus);

- oil products;

- surfactants;

- metals (iron, manganese, copper, zinc, lead, mercury, nickel);

- pesticides;

- radionuclides.

 

To improve informative value of monitoring data from the perspective of the transboundary pollution load monitoring, the sampling programme should be also expanded by including the solid state sampling exercise for a number of substances (metals, pesticides etc.).

 

For major contaminants, annual sampling frequency should be set at 24 times per year. For substances of primarily natural origin, featuring relatively stable concentration pattern over a hydrological cycle, annual sampling frequency of 12 times per year would be sufficient. In the future, the fortnightly sampling frequency for the major contaminants should be increased to 36 times per year, i.e. in line with the existing transboundary monitoring practice in the Rhine River Basin which can be considered both as a prototype and a model example.

 

Following (or in parallel with, where appropriate) the expansion of the monitoring programme for the transboundary sections, the existing monitoring programme should be revised (expanded) for the upstream, or ‘internal’ monitoring stations, in order to provide a more complete picture of pollution flow formation before it crosses a national border. As was illustrated by the instantaneous mass flow ‘snapshot’ produced on the basis of the field survey results, this relates to the monitoring stations in Mosyr (the Pripyat River) and downstream of Rechitsa (the Dnipro River). It should be borne in mind that a transboundary pollution monitoring system coverage should not be limited to the cross-border sections only.

 

Some specific recommendations can be made in respect to improvement of the pollution load monitoring at the Dnipro Estuary, where this load enters the Black Sea. In addition to the general requirement of expanded variable list and increased sampling frequencies, the monitoring programme for this section should involve sampling at different depths: sub-surface sampling procedure currently employed at the Ukrainian Hydromet monitoring station in Kherson is by no means adequate for a deep (14-16 m) river section characterised by considerable vertical non-homogenity attributed to natural factors. Moreover, no monitoring activities have been maintained in the individual branches of the Dnipro Delta (apart from the single-time surveys). Taking into account that the retention time is too short for the river to be able to self-purify itself, uncontrolled pollution from the local sources is carried directly to the Dnipro-Bug Estuary.

 

Some transboundary sections of the Dnipro Basin have highly specific water quality patterns dominated by natural factors, where ambient concentrations of certain substances considerably exceed the national water quality standards set in the riparian countries. At the same time, detailed study is required to be able to separate the ‘natural’ and ‘anthropogenic’ component in the total amount of pollution load.

 

The biological monitoring techniques are likely to contribute significantly in terms of indicating the ecological effects of changes in water quality. The 2000-2001 field survey results might be used as the baseline data in this respect.

 

In order to establish and maintain the basin management approach in the Dnipro River Basin, a permanent joint management body needs to be created (for example, the Steering Committee and/or Working Group) for development and implementation of the joint transboundary water monitoring system, assessment of transboundary pollution reduction/mitigation actions, management of the monitoring information collection and exchange process and making decisions on other issues relating to operation of the Dnipro Basin transboundary pollution monitoring system.

 

It is necessary to ensure that the proposed transboundary pollution monitoring system is compatible with the existing monitoring systems of riparian countries in the legal, methodological and institutional aspects of their operation.

 

The existing monitoring networks should be adapted to new operational arrangement where the re-siting of the existing (or establishment of new) monitoring stations should be a requirement in all cases where point or non-point pollution sources exist in the river reaches downstream of the existing monitoring stations but upstream of the border.

 

The state of transboundary water bodies should be assessed in an integrated manner, on the basis of criteria reflecting various aspects of the aquatic ecosystem functioning (hydrological, hydrochemical and hydrobiological).

 

Special data analysis procedures are required to ensure meaningful statistical interpretation. Water quality sampling inevitably introduces uncertainty, and only by statistical methods can the uncertainty be quantified and the risk of making incorrect decisions controlled.

 

It should be taken into account that trends in the bottom sediment quality take longer time to monitor than changes in water quality. For example, short-term variations of metal concentrations in water are able to be recorded, whereas longer observation period is needed to trace changes in the bottom sediment quality.

 

When planning a sampling programme, consideration should be given to natural cyclic variations occurring in a river system, so that systematic coincidence of sampling activities with peaks or lapses of natural cycle can be avoided. Higher sampling frequencies might be needed to monitor seasonal changes.

 

Given that the monitoring data will have the interstate status, sampling and analytical techniques should be chosen to the satisfaction of all parties. Use of the existing national techniques and methods which appear to be different between the countries would inevitably lead to discrepancy of results and disputes between the parties. One possible alternative could be introduction of the relevant ISO standards.

 

Taking into account that transboundary pollution monitoring is considered as an extremely important tool for efficient management of the transboundary water resource, a continuous joint monitoring programme needs to be developed, as well as data analysis procedures and protocols, so that the environmental management decisions can be made inter-governmentally and nationally on the basis of the proper quality information.