Study of Heavy Metals Existing in the Danube Wa- Ters in Turnu Severin – Bechet Section

South Western Journal of Vol.2, No.1, 2011 Horticulture, Biology and Environment pp.47-55 P-Issn: 2067- 9874, E-Issn: 2068-7958

STUDY OF HEAVY METALS EXISTING IN THE DANUBE WA- TERS IN TURNU SEVERIN – BECHET SECTION

Elena GAVRILESCU

University of Craiova, Horticulture Faculty, A.I.Cuza Street, no. 13, Craiova, Romania E-mail: [email protected]

Abstract. The Danube River Protection Convention and the Environment Programme of the Danube River Basin aim to the complex assessment of water quality at the national level and of its development trends in order to substantiate the measures and policies to reduce pollution, plus other priority objectives as the quantification of the heavy metals content (Lack 1997). The monitored sections in the study, respectively Turnu Severin - Calafat - Bechet were part of the TNMN network for tracking the Danube water quality (Harmancioglu et al. 1997).The heavy metals are from both the upstream of Turnu Severin and from the Jiu River. After the study conducted in 2007-2009 there were found in some metals significant amounts of nickel, copper, chromium, arsenic and lead in particular.

Key words: monitoring, heavy metals, aquatic ecosystem, water pollution, the Danube

INTRODUCTION

Danube represents the biggest water resource for Romania being more than double (85x109 cm/year) in comparison with the inland water (river and lakes), which represents about 40x109 cm/year, but the possibilities of their use in natural regime are limited because of different technical reasons (Botterweg & Rodda 1999). Even so the importance of the Danube health is of major concern for Romania as well as for other countries. The Danube is properly named "the river of life" having a major political and economical importance for the countries in its hydrographic basin, each of them using it in different ways. Its protection represents a crucial objec- tive, the river being a natural support for many species of flora and fauna, some of them being endangered (Barth et al. 2009). No matter how regrettable is the fact, we must admit that the activities taking place in this space have a significant impact on the environmental status of the region, threatening the drinking water supply in the case of ac- cidental pollution (Turnu Severin), and the security of fishery and tourism.

The Danube waters come already polluted in our country, from upstream. An example is the pollution from the former Yugoslavia which during the civil war led to the destruction of chemical plants on the Danube bank. In those days it began the great heavy metals pollution, namely with zinc, nickel, iron, lead, cadmium and aluminium (Teodorovic et al. 2009, Mi- lacic et al. 2010). The enhancement of navigation caused the water pollution with oil tail- ings and heavy metals, being detected significant concentrations of harmful pollutants which are on the list of priority substances (Gavrilescu 2006). The heavy metals form part of this list. Some undertaken studies have re- vealed serious contamination of the Danube River with heavy metals, including copper and nickel. The tributary streams with the highest concentrations of these substances are the Rusenski Lom, the Iskar and the Timok (Bird et al 2010). The lack of water supply systems and sewages in the rural areas con- tributes to the worsening of the Danube pollution. In addition, the moderni- zation and intensification of the agricultural practices and animal produc- tions in some years are non-stationary sources of water pollution. The ob- solete technologies, the lack of wastewater treatment and industrial waters pre- treatment plants contribute to the deterioration of water quality (Benciu 2007, Cârţână 2005). The Danube water contamination with heavy metals may come from mining, energy, food, metallurgy and chemical industry. An important issue is the waste storage sites, which are located on the banks of the water, only 23% of industrial storage sites having an environmental permit (Velea et al. 2009). The EU Water Framework Directive (WFD) specifies 33 priority substances, from which 11 pesticides. Some parts of the Danube may have 47% organic pollution, 55% nutrient pollution, 73% priority substances. The objectives of this study were: i) the qualitative and quantitative determination of heavy metals in Turnu Severin – Bechet section; ii.) the impact on the aquatic ecosystem. iii.) the comprehensive assessment of water quality in the studied section and its development trends in order to substantiate its measures and policies to reduce pollution.

MATERIALS AND METHODS

The study was conducted in the 2007-2009 period and aimed at monitoring the specific indicators, namely the heavy metals in Turnu Severin- Bechet section.

South west J Hortic Biol Environ (2011) Study of heavy metals existing in the Danube waters 49

These indicators were determined differently in relation to the particular conditions of each section under control. Thus, due to the very large width and depth it results a number of phenomena such as diffusion, dispersion and dilution of pollutants in relation to their temporal variations. The adaptation and interpretation of the basic equations of these phenomena are due to Phels. The monitoring was performed in slow flow with a monthly frequency, with em- phasis on the determination of heavy metals. The following devices were used: ADCP – a device for the assessment of velocity in profile based on Dopler effect; Echosounder – a device for measuring the water level. In each section of control there were collected samples from two locations, namely: the left bank and the centre. They were held monthly, and the average values are presented in this pa- per. The water samples were collected with samplers, forming an average sample which was stabilized with the hydrochloric acid. The heavy metals from the samples were analyzed by atomic absorption spectrometry (AAS) using AAnalyst 700 spectrometer (Literathy & Laszlo 1999).

RESULTS AND DISCUTIONS

The heavy metals present in normal concentrations in the water are not dangerous for the environment because they are found in very small quantities. In contrast, in larger quantities become pollutant mainly due to storm water enriched with heavy metals from chemical plants, power plants and nuclear plants. Another part may come from the materials from the Danube tributaries and groundwater rich in substances at different stages of biodeg- radation (insecticides, pesticides, organic substances). The heavy metals may derive also from wastewater, partially treated water, sewage or acci- dental pollution resulted from explosions, such as the chemical plants located on the Serbian bank of the Danube (Vandijk et al. 1994). To these, there are added the water of tributaries where there are discharged both water from technological processes and water from the discharge of sew- ers. In the reservoir area of the Iron Gates I, the Danube becomes a centre of collection and concentration of the pollutant wastes with heavy metals due to the reduced water flow which results in slowing down the dispersion and dilution of pollutants velocity. The cadmium is one of the elements which are present in the environment as dissolved ions. It comes from anthropogenic sources due to the industrial activities (Sakan et al. 2010). In 2007, 2008, the average values of the cadmium concentrations (0.26 μg/l and 0.23 μg/l) situate the Danube waters in the second category of quality, while in 2009 the average content of cadmium was of 0.17 μ g / l corresponding to the first category of quality. In Turnu Severin and Bechet (Figure 1) there were recorded both in the

South west J Hortic Biol Environ (2011) 50 Gavrilescu, E. studied years and at the monthly level, significant values compared with Calafat. The copper is present in water both in an ionic form or in organo-mineral complexes. The years 2007, 2008 were characterized in the three sections, in terms of copper content, by an average annual quantity of 2.16 μg / l and 2.08 μg / l, the Danube waters being in the second category of quality. It is notable an increase in the copper content in Turnu Severin and Bechet, significant amounts being recorded in March, April, May (3.86- 4.12 μ g / l) (Figure. 2).

0.45 0.4 0.35 0.3 0.25

g/l Cd g/l 0.2 0.15 0.1 0.05 0 I II III IV V V I V II V III IX X XI XII

Turnu Severin Calaf at Bechet

Figure 1. The average concentration of cadmium.

4.5 4 3.5 3 2.5

g/l Cu 2 1.5 1 0.5 0 I II III IV V V I V II V III IX X XI XII Turnu Severin Calaf at Bechet

Figure 2. The average concentration of copper.

The main sources of chromium in water are due to the untreated or partially treated wastewater, resulted from the processes of leather tanning

South west J Hortic Biol Environ (2011) Study of heavy metals existing in the Danube waters 51 and chromium metal coating. The hexavalent chromium, at levels above 0.05 ppm, can become cancerous (Varduca, 2000). The monitoring of the Turnu Severin - Bechet sections situates the Da- nube waters in the second category of quality in all the studied years. The average values are between 1.58-1.99 μg / l. Significant amounts were recorded in the three locations during spring (2.92-3.26 μg / l) (Figure 3).

3.5 3 2.5 2

g/l Cr g/l 1.5 1 0.5 0 I II III IV V V I V II V III IX X XI XII Turnu Severin Calaf at Bechet

Figure 3. The average concentration of chromium.

The nickel has an anthropogenic origin, being present in the surface waters from rainfalls and discharges of wastewater collected from various industrial units. The nickel content from the Danube waters situates them in the first and second category of quality (1.42 μg/l in 2007, 1.47 μg/l in 2008, and 1.25 μg/l in 2009). Large amounts of nickel have been reported in Bechet and Calafat in October, namely 1.46-1.56 μg/l (Figure 4). There is notable the seasonal pollutant effect of some waters reaching the Danube in various ways. A major source of lead in the aquatic environment is due to the wastewater discharge from industrial activity. Being strongly absorbed / bound by sediments and soil particles, the lead is available to plants and animals in a small amount. However, some of it is soluble, being conditioned by tem- perature, salinity, pH (Moriarty 1999). The lead content of the Danube waters is less variable in the studied sections, the average of the three years ranging between 1.26-1.31 μg/l. In terms of locations, a considerable amount of lead is reported in the area of Turnu Severin, Calafat, both in April and October. The Danube waters fall under the second category of quality (Figure 5). The pollutant effect of the lead content is increasing from

South west J Hortic Biol Environ (2011) 52 Gavrilescu, E.

Turnu-Severin to Bechet due to the cumulative effect and poor dilution because of the lack of a significant quantity of water intake (there are no tributaries with high flow in the Turnu Severin – Calafat section).

2.5

1.5

g/l Ni g/l 1

0.5

0 I II III IV V V I V II V III IX X XI XII Turnu Severin Calaf at Bechet

Figure 4. The average concentration of nickel.

1.5

1 g/l Pb g/l

0.5

0 I II III IV V V I V II V III IX X XI XII Turnu Severin Calaf at Bechet

Figure 5. The average concentration of lead.

The arsenic is the most important non- metallic element of waters being highly toxic. It is found in compounds entering into the composition of insecticides. It may come from atmosphere, in the form of powders reaching the surface waters (Haiduc 2006). The average values of the studied years are insignificant, ranging between 1.70-1.87 μg/l. The waters fall under the second category of quality. The annual variation of the arsenic content has significant net values in May and June (4.8 μg/l at Bechet, respectively 5.6 μg/l at Turnu Severin) (Figure 6).

South west J Hortic Biol Environ (2011) Study of heavy metals existing in the Danube waters 53

3 g/l As 2

0 I II III IV V V I V II V III IX X XI XII Turnu Severin Calaf at Bechet

Figure 6. The average concentration of arsenic.

The heavy metals content has an impact both in terms of water quality and from the biological point of view. The quality of the aquatic ecosystem is regarded as a whole, including not only the watercourse but also the aquatic system correlated to the riparian and terrestrial areas, to the flora and fauna as well (Teodorof et al. 2009). The heavy metals have adverse effects leading to secondary pollutions through the bioconversion carried out by the aquatic organisms (Pajevic et al. 2008). In this respect, there was assessed the saprobic index, namely the degree of water contamination (Costache & Modrogan 2006). Thus, in Turnu Severin, the saprobic index S = 2.21 shows a moderately contaminated water, situating the section in the b-mezosaprobic area – second class of quality. The representative species belong to the subkingdom Cyanophyceae (Oscillatoria subtilissima, Oscilatoria limosa), Euglenophyta (Trachelomonas rugulosa), Xanthophy- ceae. In Calafat section the saprobic index is S = 1.89, corresponding to the b- mezosaprobic area, the water being moderately contaminated. As representative taxa there were identified the species: Bacillariophyta (Pinnularia viridis, Cymbella lanceolata), Chlorophyta (Oscillatoria subtillisima) and Cyanophyceae (Chlorhormidium rivularae, Ulothrix zonata), Zygaemato- phyceae. In Bechet section the saprobic index is S = 2.08, the water is moderately contaminated, in the b-mezosaprobic area, second class of quality. As representative taxa there were identified the species: Bacillario- phyta (Navicula viridila, Cyclotella comta, Synedra actinastroides), Chloro- phyta (Chlorella vulgaris, Chlorhormidium rivularae), Cyanophyta (Micro- cystis aeruginosa), Ciliata (Paramecium bursaria). After the undertaken study it is recommended:

South west J Hortic Biol Environ (2011) 54 Gavrilescu, E.

- the monitoring of heavy metals from suspensions, excluding the dissolved phase; -the sampling points for the biological determinations should be done also in the downstream of the monitored location and on lower distances (approx. 10 km). Adding these sampling points will determine the extension of the list of taxa, which should be as complete as possible to enable the environmental assessments.

CONCLUSIONS

The heavy metals content of the Danube waters in the studied sections situates the waters within the second category of quality. Based on the ana- lytical results there was noted an annual decrease in the heavy metals content, thus in the year 2007 being recorded the highest values. The heavy metals pollution occurs over the Danube river as follows: (on the Serbian sector, from the Moldova Nouă iron ore plant and the unpre- served dumps located on the shore; on the Bulgarian bank, from the Poreca river which discharge mining residues, the nuclear plant from Kozlodui ; Severnav and Celrom companies, The Drobeta Turnu Severin Heavy Water Plant, The Calafat Thermal Power Plant (TPP), the food and textile industry, Roquette Calafat, the Jiu river– Craiova TPP I and II, Dol- jchim, Olpo Podari, The Sewer from Craiova etc.), the river traffic and agri- culture, through agricultural practices that use fertilizers and pesticides which are taken by rainwater that carries them into the river. The oil pollutions are also greatly affecting the Danube waters.

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