Study of spatial and temporal variations of some chemical pollutants of the Lower Siret River

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1 Journal of Environmental Protection and Ecology 11, No 3, (2010) Water pollution Study of spatial and temporal variations of some chemical pollutants of the Lower Siret River P. L. Georgescu*, M. Voiculescu, S. Dragan, A. Caldararu, M. Timofti Faculty of Sciences, Dunarea de Jos University of Galati, 111 Domneasca Street, Galati, Romania Abstract. There is a tremendous need of intensive studies regarding anthropogenic effects on the water quality of the Siret river. The present paper is a study of some chemical pollutants measurements made by the environmental quality laboratory of the European Centre of Excellence for the Environment (ECEE) in Dunarea de Jos University of Galati. The main purpose of the study was to investigate the water quality of the Siret river in relation with possible anthropogenic effects. Our results show that the Siret river is strongly affected by anthropogenic activities. Most of the agricultural pollution seems to originate in the upper part of the river from the Galati county. The iron and steel industry, located nearby station S3 might also indirectly affect the water quality of the Siret river, through wet deposition processes of gaseous and/or particulate matter originating by emissions of this unit. Keywords: chemical pollutants, water quality, the Lower Siret river. AIMS and background The aim of present study is to evaluate the extent of the pollution on the Lower Siret river. Several chemical compounds have been monitored monthly, for three years in order to find the most probable pollution sources along the river. The total area of the Siret hydrographic basin is km 2 with a length of the river network of km. The Siret river passes through four main relief units having a temperate climate and continental influence and mean annual precipitations between 1000 l/mp and 450 l/mp per year 1. In the monitored area the system of water recycling is different and depends on industry and factories from 10 to 95%. In agriculture, the main water use is in irrigation, where the efficiency of the water use ranges from 60 to 80%. The main problem is the lack of monitoring data, especially those data that can be used for identifying priority pollutants as well as the lack of data for the calculation of pollution loading both from point and diffuse sources. Thus there is a tremendous * For correspondence. 837

need of intensive studies regarding the anthropogenic effects on the water quality of the Siret river within the Galati county area. EXPERIMENTAL Sites.

2 need of intensive studies regarding the anthropogenic effects on the water quality of the Siret river within the Galati county area. EXPERIMENTAL Sites. Three sampling sites were established along the lower part of the Siret river, taking into account the diversity of the natural and anthropogenic influence. The stations are (Fig. 1): (S1) Cosmesti; (S2) Lungoci and (S3) Sendreni. The map in Fig. 1 shows the distribution of industrial and agricultural areas and corresponding specific activities, which might affect the quality of the water 2. The main sources of pollution in this area are agriculture, municipal and industrial wastewater and some industrial units. A major contributor to air pollution is the iron and steel plant, however this does not directly affect the measurements because in the discharge point downstream is the last station, S3. Fig. 1. Hydrographic basin of the Siret river with the distribution of industrial and agricultural sources 838

3 Methods. Data were produced mainly by ECEE laboratory. The sampling was carried out during three years ( ) on a monthly basis, according to officially approved monitoring techniques 3,4.The concentrations of the following species were determined: sulphate (SO 4 ), ammonium (NH 4 ), nitrite (NO ), nitrate (NO 3 ), total phosphorus (TP), orthophosphate (PO 4 3 ). The analytical methods used for establishing chemical concentrations were the following: ammonium (NH 4 ) EPA 350.1, US Standard Methods 4500-NH 3 ; nitrite ions (NO ) EPA 354.1, US Standard Methods 4500-NO 2 B; nitrate ions (NO 3 ) ISO 7890/1; phosphate ions (PO 4 3 ), and total phosphorus EPA , US Standard Methods 4500-PE; sulphate ions (SO 4 ) EPA and US Standard Methods 4500-SO 4 E. Sources of pollution. The main categories of pressures in the hydrographic area of the river are point source pollution (sewage, industrial units, agricultural farms, municipalities with improper functioning of the waste water treatment plants), diffuse pollution (agricultural activity) and hydromorphological alterations 5. RESULTS AND DISCUSSION Figure 2 displays the NH 4 variation and shows that, except for a small period in the beginning of 2007, the highest concentration is observed at the middle station, S2. Although NH 4 varies rather chaotically, the values are almost always smaller at S3 than at S2. NH 4 reaches its maximum at S2, suggesting that most of the NH 4 pollution comes from somewhere between S1 and S2. Between stations S1 and S2 the possible sources are wastewaters coming mostly from the Tecuci area. Most of the large agricultural farms using fertilisers are also located in this area (Fig. 1). An important increase in the NH 4 content is observed in Dec.Jan.Feb A similar increase is seen for SO 4 (which will be discussed later). Ammonium ions are indicators of organic pollution on very spot and/or recent sources 6. In cold seasons the concentration of NH 4 at S1 is the highest, which indicates that the main pollution sources are in the upper part of the river. Fig. 2. NH 4 variation during for the three stations: S1 continuous line with crosses; S2 dashed line with diamonds; S3 dotted line with x markers 839

4 The behaviour of NO 2 (Fig. 3) varies. The concentration is smaller upstream, with higher values at the middle station and highly irregular values at the downstream stations. This suggests an anthropogenic contribution coming from agriculture sources located mainly between S1 and S2 (see Fig. 1). In 2007 the concentration of NO 2 decreases from S1 to S3; reduction of quantities of NO 3 and NO 2 ions is probable caused by biological organisms presence who metabolise those ions 7. The comparison between the NO 2 variation (Fig. 3) and flow shows a good correlation between NO 2 and water debit increases especially for stations S2 and S3: May and July 2005, April and June The NO 2 increase in May 2005 is accompanied also by similar increases in TP, PO 4 3, and NO 3 and by ph decreases. The most likely cause of these increases is the fact that heavy rains washed out important quantities of agricultural chemical compounds, animal waste and other animal farm residues along the entire river. Similarly to NO, NO 3 (Fig. 4) has no clear seasonal or spatial variation. When the temperature is low the concentration at station S1 is relatively higher than its counterparts at the other two stations; this is most probable because of the process of growth in warm period and non-growth of biological organism in cold period. Fig. 3. NO 2 variation during for the three stations: S1 continuous line with crosses; S2 dashed line with diamonds; S3 dotted line with x markers Fig. 4. NO 3 variation during for the three stations: S1 continuous line with crosses; S2 dashed line with diamonds; S3 dotted line with x markers 840

5 The two chemical phosphorus parameters (TP, PO 4 3 ) vary almost hand in hand (Fig. 5). Similarly to the previous cases, there is no clear seasonal or upstreamdownstream variation. The concentration at station S1 (continuous line) is, however, clearly different from the other two stations for both chemical components. Besides the event in May 2005 that was discussed previously, there are no clear correlations with other physical parameters or with other pollutants. a b Fig. 5. Total P (a) and PO 4 3 (b) variation during for the three stations: S1 continuous line with crosses; S2 dashed line with diamonds; S3 dotted line with x markers For SO 4 (Fig. 6) the results show some seasonal variations, with slightly higher values of SO 4 concentration in winter than in summer, which is better seen for 2005 and There is an obvious increase in the content of SO 4 from upstream to downstream which is observed each year. Another interesting observation is that the difference between the three stations diminishes in 2007 compared to 2005, especially for S2 and S3. This suggests that anthropogenic contribution from downstream affects a large area. The SO 4 variation in 2006 is different from the neighbouring years. Firstly, the concentration is clearly higher by a factor of about 2 in comparison with the other two years. The decrease in April 2006 is clearly correlated with the significant increase in the water debit. During this particular year there is a strong anticorrelation between the SO 4 concentration and water 841

6 flow, characterised by a correlation coefficient of 0.7 with 0.95 confidence level. This anti-correlation could be based on the fact that for constant quantities of a given chemical compound a higher water debit should, indeed, result in smaller concentrations. However, this is not valid for the other two years. If the anticorrelation between water debit and SO 4 concentration would be a rule, smaller SO 4 concentrations should coincide with the significant flow increases in July 2005, May 2005 and March This is not seen in Fig. 6 for 2005 and We may conclude that the increases of the water flow have no effect on the SO 4 concentration as long as the latter has relatively low (normal) values, but could result in the dilution of the pollutant if the SO 4 concentration is significantly high. a b Fig. 6. SO 4 variation (a) during for the three stations and water debit (b): S1 continuous line with crosses; S2 dashed line with diamonds; S3 dotted line with x markers Taking into account the average value of the SO 4 concentration and the different behaviour in 2006, our interpretation of Fig. 6 is the following: in the end of 2005 and during the first half of 2006 large quantities of SO 4 compounds have been discharged along the Siret river, mostly downstream, where is the highest influence of iron and steel industry. The measured concentration of SO 4 abruptly decreases in April 2006, when the water debit increases, going up again to the previous values when the water debit goes back to normal values. This is followed 842

7 by a similar process in June (SO 4 concentration decline coinciding with debit augmentation). Finally the SO 4 concentration levels down to the average values seen in the other two years. A comparison with the other chemical compounds shows that, in the same period, increases between S2 and S3 were found in NH 4 and in TP and/or PO 4 3. One of the potential common sources could be a major discharge of wastewater somewhere between S2 and S3. For SO 4 another possible explanation are the airborne particles brought by wind to the hydrographic basin of the Siret river from the iron and steel unit area, which is located very close to S3. The pollutant concentration decreases with distance, which would explain the decrease of SO 4 concentration upstream the river. Table 1. Sources of pollution Sources Steel industry Food industry Wastewater Landfill Agriculture Livestock farms Construction materials manufacture Petrochemical industry Pollutants SO 4 NH 4 NO 2 NO 3 TP 3 PO 4 CONCLUSIONS Our results show that the Siret river is strongly affected by anthropogenic activities. Most of the agricultural pollution seems to originate in the upper part of the river from the Galati county. The iron and steel industry, located nearby S3 might also indirectly affect the water quality of the Siret river, through wet deposition processes of gaseous and/or particulate matter originating by emissions of this unit. The study of this possibility is presently under way. Acknowledgements. This study was supported by the Grant SOP HRD/6/1.5/S/15 SIMBAD cofinanced by ESF of EC, Romanian Government and University Dunarea de Jos of Galati. REFERENCES 1. National Administration Romanian Waters (NARW): The Plan for Hydrographic Area of Siret River Ministry of Environment and Water Management (MMGA) and National Administration Romanian Waters (NARW): Management Plans for River Basins of Romania

8 3. J. BARTRAM, R. In. BALANCE, J. BARTRAM, R. BALANCE: Water Quality Monitoring. A Practical Guide to the Design and Implementation of Freshwater Quality Studies and Monitoring Programmes. Chapman and Hall, 1996, p Ministry of Environment and Water Management (MMGA): Plan of Monitoring, Guide for the Modernization and Development of Integrated Water Monitoring System in Romania United Nations Department Programme (UNDP): Freshwater Country Profile. Romania J. J. B. NEVADO R. C. R. MARTIN-DOIMEADIOS, F. J. G. BERNARDO et al.: Integrated Pollution Evaluation of the Tagus River in Central Spain. Environ. Monitoring Assessment, DOI /s , WU SHIKAI, XIE PING, WANG SONGBO, ZHOU QIONG: Changes in the Patterns of Inorganic Nitrogen and TN/TP Ratio and the Associated Mechanism of Biological Regulation in the Shallow Lakes of the Middle and Lower Beaches of the Yangtze River. Science in China: Series D: Earth Sciences, 2006, Vol. 49, Supp. I, Received 7 July 2009 Revised 2 November

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