HEAVY METALS CONCENTRATIONS IN AQUATIC ENVIRONMENT AND LIVING ORGANISMS IN THE DANUBE DELTA, ROMANIA

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1 HEAVY METALS CONCENTRATIONS IN AQUATIC ENVIRONMENT AND LIVING ORGANISMS IN THE DANUBE DELTA, ROMANIA MIHAELA-IULIANA TUDOR, MARIAN TUDOR, CRISTINA DAVID, LILIANA TEODOROF, DANA TUDOR AND ORHAN IBRAM Department of Limnology Danube Delta National Institute for Research and Development 165 Babadag Str, Tulcea, Romania *To whom correspondence should be addressed: Abstract. A major role in terms of danger to the aquatic ecosystem is played by heavy metals, which stand out by their persistence and accumulability. In this study an overview on recent monitoring ( ) of some heavy metals (Cu, Zn, Cd, Pb) analyzed in fish species, plants and benthic macro invertebrates from Danube Delta Biosphere Reserve.In the system of contamination classes elaborated by (Wachs B. 2000), for the grading of the situation of ecosystems in term of heavy metal content, of all the various compartments, fish constitute the only critical part. The fish organs - in particular the muscles show a very wide spread of concentration. Fish are very sensitive to cadmium and lead poisoning, but certain species, for example roach, perch and gibbel carp in aquatic ecosystem from Danube Delta was found with high concentration of cadmium and lead. The accumulation of contaminants in aquatic organisms can prove harmful to a number of fish species during sensitive stages within the lifecycle. Concentrations in aquatic plants was higher special in Ceratophyllum demersum Cd (1.89 mg/kg wet substance) and Pb (23,2 mg/kg w.s.).variations of heavy metal concentrations from different sampling stations are discussed. Results indicate that the levels of lead and cadmium were highest concentration Keywords: heavy metals; fish species; aquatic vegetation; macroinvertebrates; bioconcentration 435 L. Simeonov and E. Chirila (eds.), Chemicals as Intentional and Accidental Global Environmental Threats, Springer.

2 Introduction In the paper there are analyzed the heavy metals concentrations in aquatic environment and living organisms in the Danube Delta, during the last three years. The effects of heavy metals on freshwater ecosystems heave been investigated by examining a number of organisms including fish, invertebrates, and aquatic macrophytes. Fish have been widely studied because of their economic and regression value. Monitoring programs and research for metals in the environmental samples have become widely established because of concerns over accumulation and toxic effects, particularly in aquatic organisms and to humans consuming these organisms. Factors known to influence metal concentrations and accumulation in aquatic organisms include metal bioavailability, season of sampling, hydrodynamics of the environmental, size, sex, changes in tissue composition and reproductive cycle (Boyden 1981). Element concentrations (Cd, Pb) in fish muscle at the same location (lake) differ between different species and individuals due to speciesspecific capacity to regulate of accumulate trace metals (Otchere 2003). Different individuals in the same community at the same trophic level could accumulate heavy metals differently due to differences in habitat/niche s physical and chemical properties. 2. Methods Previous investigations concerning freshwater contamination, aquatic macrophytes, inveretebrates and fish. In the field there were 9 sampling points represented by fish collecting points Figure 1, so the fish samples were representative for and area of the Danube Delta Biosphere Reserve. There are three categories of areas in the Danube Delta Biosphere Reserve: first are the core areas strictly protected areas, were no humans activities are allowed, except research. The second category are the buffer areas, were are allowed traditional activities and the third category are the economic areas were economic activities are allowed, including commercial fishing. In each sampling point were collected 6 adults individuals for each of sixteen fish species, monitored. For all the species were determined the concentrations of four heavy metals: zinc, copper, cadmium and lead. Fish samples were chosen from different ages and weights to be analyzed along with samples of the aquatic plant, macroinvertebrate and lake water.

3 437 `Metal concentrations in fish were compared using guidelines established by the Romanian Council of Ministers of the Environment (Ordin No. 356/2001): Maximum limits for metals accumulated in fish tissues (fillet): Lead (Pb) 0.2mg/kg Cadmium (Cd) 0.05 mg/kg Zinc and Cupper is not includes in this guidelines. Mean concentrations were calculated (Figures 4, 5.) and compared to consumption values established for the protection of human health. LEGEND Fish sampling points 1. Caraorman 2. Crisan 3. Gorgova 4. Matita 5. Mila Razelm 7. Rosulet 8. Somova 9. Sfântu Gheorghe FIGURE 1. Sampling points collection in Danube Delta Biosphere Reserve. 3. Discussion and Conclusion The result of this activity is the main purpose of the research due to the potential risk for human health represented by the heavy metals accumulated in fish. The concentrations of all 4 metals increased in macrophytes and fish.

4 438 The highest levels of Cd in muscle tissue were found in fish Carassius auratus gibelio (0.19mg/kg-0.06 mg/kg), Perca fluviatilis (0.20 mg/kg-0.08 mg/kg) and were high the upper limit recommended for human consumption (0.05 mg/kg) (Figure 2) mg/kg wet tissue Cd mg/kg 2003 Cd mg/kg 2004 Cd mg/kg zander perch roach wels silver carp pike rudd gibel carp bream tench carp white bream asp ziege mackerel FIGURE 2. Content of cadmium in fish muscle (Danube Delta) The highest lead concentrations were determined in pike (2,4 mg/kg w.t.), gibbel carp (2.6 mg/kg w.t.), perch (3,9 mg/kg w.t.) and roach (1.3 mg/kg w.t.), (Figure 3). mg/kg wet tissue Pb mg/kg 2003 Pb mg/kg 2004 Pb mg/kg 2005 perch gibel carp rudd pike bream tench roach wels white bream carp zander silver carp mackerel ziege asp FIGURE 3. Content of lead in fish muscle (Danube Delta)

5 439 Levels of cadmium acumulation in the muscles of perch, zander, pike, caught in lakes 2003 was very high. TABLE 1. A comparison of the bioconcentration factors for fish with those for the faunal species fish feed on. bioconcentration factors (BCF) Heavy metal Fish muscle (Wachs B. 2000) // RBDD* (constricted range) zoobenthos(wachs B. 2000) // RBDD (constricted range) Cd (-200) // ,000-50,000 // 1,121-4,387 Cu (-200) // ,000 // 2,810-2,934 Pb // ,000 // 5,058-8,608 Zn (-700) // ,000 // 9,662-27,202 leech (Wachs B. 2000) // RBDD (constricted range) 1,400 // 0,336 1,700 // 2,330 1,400 // 0,474 (RBDD*-Constricted range of heavy metals analysed in Danube Delta Biosfere Reserve) 6,000 // 72,187 In the ecosistem of flowing waters suspended matter and the periphyton mass exhibit the highest of heavy metal concetration. A mean level of acumulation can be observed in the bentic fauna and in the aquatic macrophites, whereas the smallest concentration factors are found in fish muscle(wachs B. 2000). Based on the results of this study cadmium and lead concentration in whole fish in 2003 to 2005 are high. The concentration factors listed in Table 1 serve to indicate the topological sequence of specific element enrichment in the muscles of fish: Zn>Cu>Pb>Cd = sequence of the heavy metal accumulation in the fish (muscles) in the Danube Delta lakes. Sence fish in their natural environment do not accumulate the persistent contaminating group of heavy metals on the parth of biomagnification, they therefore exibit relatively low bioconcentration factors based on wet weight. Biomagnification is a phenomenon which is to date not fully understood. It is imperative to understand biomagnification if the protection of organism of all trophic levels is to be considered. An understanding of the metal content of food source of higher trophic levels, and the environment in which they live, must be assessed (Timmermans 1992; Goodyear 1999).

6 440 Concentrations of heavy metals (Cd, Pb, Zn and Cu) were measured in three species of aquatic macrophytes collected from the lakes (Fortuna, Nebunu, Razelm, Sinoe, Somova) Ceratophyllum sp., Myriophyllum sp., Potamogeton sp., and aquatic macro-invertebrates Chironomidae, Gammarus sp. Analyses of water, and plant samples indicated that the lakes (Figures 4, 5) were polluted with Pb, Cd, and partly with Cu and Zn. mg/kg w.s. 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Fortuna Nebunu Razelm Sinoe Somova Cu mg/kg w.s. Pb mg/kg w.s. Cd mg/kg w.s. Zn mg/kg w.s. lakes FIGURE 4. Metal concentration in aquatic macrophytes. In macroinvertes and aquatic macrophytes, levels for toxic metals, such as lead and cadmium is more than in water. A generalised concentration gradient of metal concentrations in aquatic plants and macroinvertebrates follows thus: Cd<Pb<Cu<Zn. As a result, relationships between environmental metal concentrations and those in organisms are not well understood. In conclusion, the metals Cu, Zn in lakes water and fish are within permitted levels, except Pb and Cd which are more higher than maximum limits admited established by the Romanian Council of Ministers of the Environment (Ordin No. 356/2001). According to national guidelines, the high concentration of lead and cadmium in fish was find in fish species like: zander, perch and gibel carp. In general, however, piscivorous fish show lower contents than non predatory fish; depending on the species of adult fish selected and compared. The mean values reported for each species may be useful as indicators of metal concentrations in tissue of fish from Danube Delta lakes and be considered possible danger for human health.

7 441 mg/kg w.s. 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Fortuna Nebunu Razelm Sinoe Somova Cu mg/kg w.s. Pb mg/kg w.s. Cd mg/kg w.s. Zn mg/kg w.s. lakes FIGURE 5. Concentration in aquatic macroinvertebrates. Further investigation of more species, for more metals, and over greater concentration ranges are needed to develop the understanding of bioacumulation in fish in Danube Delta lakes. ACKNOWLEDGEMENTS The authors would like to thank to all the technical staff involved in collecting and preparing of the samples and to the commercial companies which allowed this research activities in their fishing areas. References Boyden, C.R., Phillips D.J.H., (1981). "Seasonal variation and inherent variability of trace elements in oysters and their implications for indicator studies." Mar. Ecol. Prog. 5: Goodyear, K.L., McNeill S., (1999). "Bioaccumulation of heavy metals by aquatic macroinvertebrates of different feeding guilds: a review." Science of the Total Environment 229: Maletin S., D.N. (1992). "Heavy metal content in fish from Backwater Tisza (Biser island)." Tiscia 26: Otchere, F.A. (2003). "Heavy metals concentrations and burden in the bivalves (Anadara (Senilia) senilis, Crassostea tulipa and Perna perna) from lagoons in Ghana: Model to describe mechanism of accumulation/excretion." African Journa l of Biotechnology Vol. 2(9)( ):

8 442 Timmermans, K.R., Spijkerman E., Tonkes M., (1992). "Cadmium and zinc uptake by two species of aquatic invertebrate predators from dietary and aqueous sources." Can J. Fish Aquatic Science 49: Wachs B. (2000). "Heavy metal content in Danubian fish." Arch. Hydrobiol. Suppl. 115/4: