Review of the 2000-2001 field survey results. Assessment of impact of transboundary pollution transport on the environmental situation in the Basin (local and global effects)

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3.3.2. Review of the 2000-2001 field survey results. Assessment of impact of transboundary pollution transport on the environmental situation in the Basin (local and global effects)

 

As a result of international field surveys carried out in the transboundary sections of the Dnipro River Basin during 2000-2001, new original data were collected. In particular, landscape diversity assessment surveys and a review of the current state of nature reserves and protected areas located in the transboundary sections of the Dnipro River Basin were undertaken. This has provided a basis for the identification of issues and problems relating to the conservation of the landscape and biological diversity in the Basin. Figure 3.13 shows the locations of sampling sites for the 2000-2001 field surveys.

 

 

Figure 3.13 Locations of sampling sites for the 2000-2001 field surveys

 

The surveys 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. Landscape and biological diversity conservation capacity in nature reserves and protected areas in the Basin is also inadequate. It was also shown that although such areas could be used as a reference basis for the purposes of ambient water quality monitoring, they are currently not.

 

Water Quality

 

In terms of ecological/sanitary criteria, the examined water bodies can principally be described as moderately polluted or dirty, corresponding to Water Quality Categories 5-7. The prescribed Maximum Allowable Concentration (MAC) limits for fishery water use were found to be exceeded in the majority of water bodies for a range of parameters (COD, BOD₅, sulphates, ammonium and nitrites).

 

Metal contamination

 

The field survey results confirmed that metal concentrations were relatively high in the transboundary river sections of the Dnipro Basin, where fishery MAC limits for metals were exceeded in all water samples. All bottom sediment samples were found to contain iron and manganese at significant 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 water, bottom sediment and aquatic biota samples from the transboundary sections of the Dnipro Basin indicate that these media have accumulated considerable quantities of these substances (Figure 3.14).

 

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

 

 

Figure 3.14 Excessive concentrations of metals and arsenic in fish sampled
during the 2001 field survey

 

Persistent organic contamination

 

During the spring field survey, all but two water samples (from Lake Nobel and the Seim River) were found to contain oil products at concentrations exceeding the MAC limit set for fishery water use. Many exceeded the MAC limit for potable and recreational water use, with levels up to 3.7 times higher than that set.

 

High levels of pesticides were found in water samples from the rivers Sozh, Ipout, Styr, Slovechna, Pripyat, Seim and the Dnipro itself. Analytical results indicated that HCCH, n,n'-DDT and its metabolites were the predominant organochlorines found in transboundary river water samples (Figure 3.15). a-HCCH was detected in 72% of all water samples at 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. Levels of n,n'-DDT were found to be below the detection limit in most 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 organo-chlorine pesticides were found in water samples taken from Lake Nobel, the Kyiv reservoir, the Seim River and the Desna River section between the villages of Kamen and Chernigov.

 

Treflane, Harness and synthetic pyrethroid herbicides were not detected in any of the water samples taken during the field surveys. However 2,4-D 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. Organo-chlorine pesticides were present in bottom sediment samples at levels reflecting their global dispersion pattern. Moreover, 38% of the bottom sediment samples were found to contain treflane.

 

 

Figure 3.15 Chlorinated organic pesticides in water of the Dnipro River Basin

 

Organo-chlorine pesticides were detected in all fish samples at levels considerably higher than their ambient concentrations in water. A clear pattern of organo-chlorine pesticide contamination emerged from the analysis of freshwater fish species (pike, perch, pike perch, catfish, ide, bream, and rudd). The highest contamination levels were detected in liver samples, with lower concentrations being generally present in fish muscle. There was a general trend of higher contamination levels in predator fish samples (pike, perch, and pike perch) compared to the benthophage fish species.

 

The major organo-chlorine pesticides detected in all fish samples were a- and g-HCCH, n,n'-DDT, n,n'-DDE, n,n'-DDD, and heptachlor. Accumulated pesticide metabolites, in particular n,n'-DDE, were detected in fish muscle and organs, indicating major metabolic changes since 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. In addition, there appear to be differences among water bodies in terms of the level of pesticide accumulation in shellfish.

 

Microbiological contamination

 

High levels of bacterial contamination were recorded in the transboundary sections of the Pripyat River tributaries during the autumn field survey (Table 3.12. The number of lactopositive Escherichia coli in samples from the Snov and Sudost Rivers exceeded the MAC limits for recreational/domestic water uses by 1.2 times.

 

Table 3.12. Bacterial contamination in the transboundary sections of the Pripyat River tributaries

 

 

The lowest quantities of bacterial plankton and heterotrophic micro-organisms were in samples collected from the transboundary section of the Desna River. During the autumn 2000 field survey, 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 (Escherichia coli, 60,000 cells/l). During the spring field survey, a 3.6-fold increase in the quantity of heterotrophic organisms was recorded for this section. This was attributed to pollution carried from the adjacent 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).

 

The highest bacterial contamination levels were recorded in the transboundary section of the Vorskla River (downstream from the village of Lugovoe). Wastewater discharges from the local dairy and municipal wastewater treatment plant have affected the hydrobiological regime of the river. 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 at 1,800 cells/ml and 4,430 cells/ml, respectively.

 

Ecological status

 

Overall, 473 phytoplankton species representing 8 groups were recorded in the Dnipro Basin, with 321 species found in the transboundary sections of the Basin. Phytoplankton community structure data indicates that the water can be characterised as ‘moderately polluted’ by organic substances in the transboundary sections. The field survey results on zooplankton community structure indicate that pollution levels were relatively low. Water quality in the Pripyat River Basin was mainly affected by factors of natural origin, whilst anthropogenic factors played a major role in the Dnipro River and its left-bank tributaries.

 

Zoobenthos is an important indicator of aquatic ecosystem state and there appear 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 widely among the rivers. Only in the Goryn River, did the state of benthic communities suggest significant inputs of organic pollution from local sources. Interpretation of zoobenthos diversity and abundance indices suggests that anthropogenic factors have not caused persistent effects on the state of the ecosystem.

 

Field survey results and a review of the specialist literature showed that there was considerable diversity of parasites (up to 200 species) 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 in fish (Trypanosome, Microsporidia, Diplostomuma, and Ligula). Moreover, the following pathogenic species were also found: Opisthorchis felineus, Metagonimus yokogawai, Pseudamphistomum truncatum, Metorchis albisus, Mesorchis denticulatus, Apophallus muehlingi, and Diphyllobothrium latum (Figure 3.16).

 

 

Figure 3.16 Parasitic invasions in B.leachi mollusc sample (the Vorskla River)

 

Water and sediment samples from the Dnipro River Basin were analysed for toxicity with a set of animal and plant bioassays. River water samples analysed for toxicity in the field were found to contain no toxic substances at detectable levels, whereas chronic toxic effects were found in the laboratory. No toxic substances were detected in bottom sediment samples.

 

Radionuclide contamination

 

In the majority of the Dnipro tributaries, ⁴⁰K activity concentrations were found to have stabilised at levels ranging from 0.02 to 0.35 Bq/l. Due to the lower mineralisation levels in the water of the upstream tributaries of the Dnipro River, specific activity levels of ⁴⁰К were lower than in the downstream tributaries. Levels of ⁴⁰К in bottom sediments correlated well with data on concentrations in soils, suggesting that the major inputs of this radionuclide are associated with surface runoff and groundwater sources. Generally, the specific activity of ⁴⁰К in bottom sediments increased downstream. Bottom sediment samples from the downstream tributaries had slightly higher levels of ⁴⁰К activity than samples from the Dnipro reservoirs. This was attributed to higher dilution rates and micro-organism abundance levels in the water of the reservoirs.

 

The highest levels of total beta-radioactivity and ⁴⁰K were found in sandy bottom sediment samples from the Sozh River, whereas the bottom sediments from the Slovechna and Ubort Rivers had the lowest levels. It should be noted that these radioactivity levels were recorded during the spring flood period, which can be attributed to higher inputs carried with surface runoff from the territories contaminated as a result of the Chernobyl accident.

 

Concentrations of ¹³⁷Cs in the bottom sediments of the Middle and Lower Dnipro tributaries varied within a range of 5-46 Bq/kg. The range was wider in the Upper Dnipro Basin (2.3-100 Bq/kg) due to the immediate proximity of the Chernobyl Nuclear Plant and the ‘spotty’ distribution of radioactive contamination.

 

Maximum concentrations of ¹³⁷Cs were recorded in the Pripyat River tributaries (up to 435.0 Bq/l), the Upper Dnipro tributaries (146.0 Bq/l), the Kyiv reservoir, a major trap for Chernobyl-related radionuclide contamination (up to 263.0 Bq/l) and the Snov River (102.0 Bq/l). Levels of ⁹⁰Sr in bottom sediments correlated well with ¹³⁷Cs concentrations, suggesting exposure to localised sources of radioactive contamination as a result of the Chernobyl accident. The highest level of ⁹⁰Sr was found in bottom sediment samples from the Pripyat River within the 30-km Chernobyl zone (4.8 Bq/kg of dry sample mass), whereas samples from the Ubort River had the lowest levels (0.27 Bq/kg). The distribution of radionuclides in bottom sediment samples was similar to that of water samples, although more pronounced reflecting the overall picture of radionuclide contamination as a result of the Chernobyl accident.

 

Bivalve molluscs act as natural filters, contributing significantly to river self-purification processes. Data on radionuclides in bivalve molluscs sampled in the Pripyat River Basin indicate that such species as Dreissena and Unito pictorum are the most powerful biological filters in the freshwater macrozoobenthic community with accumulation factors of over 1,100 for ⁹⁰Sr in Dreissena, and near 500 for ¹³⁷Cs in Unito pictorum.

 

Radionuclide contamination in the Dnipro River Basin is very uneven in distribution, suggesting strong local sources of an anthropogenic nature. Tritium is a major radioactive component of effluent generated by nuclear power facilities and is regarded as a dangerous long-lived radionuclide capable of spreading far beyond its immediate source. Tritium concentrations in water were generally below or slightly above the detection limits of the measurement techniques involved in this study (up to 3.4 Bq/l). The only exceptions were water samples from the Styr River where the tritium concentration was 7.5 Bq/l, possibly as a result of the Rivne Nuclear Power Plant.

Assessment of the ecological status of the Dnipro Basin on the basis of national techniques adopted in the riparian countries

 

The Water Pollution Index (WPI) technique is used in the Russian Federation, the Republic of Belarus and Ukraine as a tool to assess surface water quality. The calculation procedure for WPI involves determining the mean annual concentrations of six substances. Two of them (dissolved oxygen and BOD₅) are compulsory and the other four can be chosen from a priority list of substances ranked in terms of the rate of the maximum admissible concentration  (MAC) exceedence at a given site. Based on data provided by the National Monitoring System, the four additional parameters involved in the WPI calculation procedure are ammonium nitrogen, nitrite nitrogen, zinc, and oil products. The WPI-based water quality classification system includes seven water quality categories or classes (Figure 3.17).

 

 

Figure 3.17 Water quality classification on the basis of WPI values

 

The rivers of the upper part of the Dnipro Basin within the Russian Federation can be described as ‘moderately polluted’ in terms of WPI values.

 

In the Republic of Belarus, WPI values indicate that ambient water quality in the Dnipro River between Orsha and Bykhov is generally undisturbed, whereas water in the river section between Rechitsa and Loyev is ‘moderately polluted’, suggesting a progressive downward trend in water quality. The WPI values for the Berezina River indicate relatively stable water quality upstream of Svetlogorsk, although the downstream section of the river has deteriorated over recent years. Consistently high pollution levels have been reported for the Svisloch River section downstream of the municipal wastewater treatment plant serving the City of Minsk. The Pripyat River tributaries (Slutch, Tsna, Ptich, Bobrik, Moroch, Ubort, and Oressa) have a relatively stable water quality regime and can be described as ‘moderately polluted’ in terms of water quality classification. There appears to be no sign of water quality improvement in the transboundary sections of the Dnipro River and its tributaries where they enter Ukraine. Moreover, the WPI values increase within the transboundary section of the Dnipro River itself.

 

Within Ukraine, the rivers of the Dnipro Basin are characterised as ‘clean’ and ‘moderately polluted’. The pattern of WPI values for the Dnipro Basin is shown in Figure 3.18.

 

 

Figure 3.18 Variation of WPI values along the Dnipro River within the Republic of Belarus

 

Transboundary transport of pollution in the Dnipro Basin

 

The existing water quality monitoring system has not been designed to quantify transboundary pollution loads carried by river flow from or to the riparian countries of the Dnipro Basin. The closest cross-border water quality monitoring stations are often located 60-100 km from the border and the transboundary hydrological monitoring network is inadequate with monitoring carried out on an infrequent basis. Therefore it is virtually impossible to calculate mass load values at a required level of accuracy and precision (e.g. 10% error at 90% confidence).

 

The mass load estimates calculated in this section are considered to be very approximate. In order to minimise potential error, only averaged values over the period of 1995-2000 were included in calculation procedure. Calculation results are presented in Tables 3.13–3.16.

 

As can be seen from the these tables, there appear to be significant differences in mass flow estimates made on the basis of data collected at adjacent monitoring stations located on either side of the border. Nonetheless, the exercise itself is very useful, as it helps to appreciate the order of magnitude involved and clearly illustrates the need for establishing a special monitoring regime in the transboundary sections of the Basin.

 

Taking into account the flawed character of the input data involved in the calculations, the derived mass flow values must be considered as a very rough estimate. These values should not be used as a basis for evaluating and claiming damage incurred to the 3 riparian countries as a result of transboundary pollution.

 

Table 3.13(A). Estimated mean annual mass load at the Ukrainian/Belorussian border over the period of 1995-2000 (tonnes/year)

 

Note: Calculations on the basis of the RB monitoring data were made by the Belorussian experts.

 

Table 3.13(B). Estimated mean annual mass load at Ukrainian/Belorussian border over the period of 1995-2000 (tonnes/year)

 

Note: Calculations made by the Belorussian experts (Pripyat-Narovlya) and Ukrainian experts (Pripyat-Chernobyl).

 

Table 3.13 (C). Estimated mean annual mass load at the Ukrainian/Belorussian border over the period of 1995-2000 (tonnes/year)

 

Note: Calculations made by the Belorussian experts (Dnipro-Loyev) and Ukrainian experts (Dnipro-Nedanchichi).

 

Table 3.14. Estimated mean annual mass load at the Russian/Belorussian border over the period of 1995-2000 (tonnes/year)

 

 Note: Calculations made by the Belorussian experts (Dnipro-Orsha, Sozh-Krichev, Ipout-Dobrush) and Russian experts (Dnipro-Smolensk, Ipout-Dobrodeevka)

 

Table 3.15. Estimated annual mass load carried by the main Dnipro tributaries across the Russian/Ukrainian border (tonnes/year)

 

Note: Calculations made by the Russian experts.

 

Table 3.16. Averaged mass flow estimates for the Dnipro-Kherson section (estuary) based on the 1998-2000 data

 

 Note: Calculations made by the Ukrainian experts.