Ewa Jurkiewicz-Karnkowska* Kumulacja metali ciężkich w wybranych gatunkach ślmaków dolny Bug i zbiorniki jego terenów zalewowych

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1 Ochrona Środowiska i Zasobów Naturalnych nr 48, 2011 r. Ewa Jurkiewicz-Karnkowska* Accumulation of heavy metals in selected gastropod species lower Bug River and its floodplain water bodies Kumulacja metali ciężkich w wybranych gatunkach ślmaków dolny Bug i zbiorniki jego terenów zalewowych Słowa kluczowe: metale ciężkie, ślimaki, zbiorniki terenów zalewowych. Key words: heavy metals, gastropods, floodplain water bodies. Analizowano stężenia metali ciężkich (Cu, Zn, Mn, Fe, Pb, Cd) w tkankach miękkich i muszlach trzech gatunków ślimaków: Lymnaea stagnalis L., Viviparus viviparus (L.) i Viviparus contectus (Millet). L. stagnalis i V. viviparus występowały zarówno w korycie rzeki, jak i w zbiornikach jej terenów zalewowych, stąd możliwe było porównanie stężenia metali ciężkich w tych 2 gatunkach zebranych w dwu wymienionych typach siedlisk. Stężenia metali w mięczakach były na ogół charakterystyczne dla niezanieczyszczonych środowisk wodnych. Ich wartości były większe w mięczakach ze zbiorników terenów zalewowych lub podobne z obu typów siedlisk. Mogło to wynikać z większej kumulacji metali ciężkich w siedliskach stagnujących (tj. zbiornikach terenów zalewowych) w porównaniu z korytem rzeki. W obrębie zbiorników wodnych terenów zalewowych stwierdzono liczne istotne różnice między stężeniem metali ciężkich w L. stagnalis i Viviparus spp., nie znaleziono natomiast takich różnic między dwoma gatunkami z rodzaju Viviparus V. viviparus i V. contectus. Porównanie stężenia metali ciężkich w V. viviparus i L. stagnalis z tych samych czterech zbiorników wykazało brak istotnych różnic zarówno wewnątrzgatunkowych, jak i międzygatunkowych. * Dr hab. Ewa Jurkiewicz-Karnkowska, prof. nadzw. UPH Wydział Przyrodniczy, Uniwersytet Przyrodniczo-Humanistyczny w Siedlcach, ul. B. Prusa 12, Siedlce; tel.: ; karnkowska@uph.edu.pl 316

2 Accumulation of heavy metals in selected gastropod species: lower Bug River and Introduction The river Bug is the biggest tributary of the Narew River and one of the largest rivers in Poland (4 th as concerns the length). It is 755 km long with a basin area of 39,420.2 km 2. The Bug River is one of few rivers in Europe, which in its whole course preserved not only natural channel, but also experienced relatively minor transformation of its valley. The fluvial processes are still the major shaping and diversifying factor affecting habitats in the river s bed and floodplain. Water quality of the lower Bug River is relatively low [Woyciechowska, Dojlido 2003, Stan 2010], in spite of its improvement during last years. Coli index, concentrations of phosphorus compounds, suspended matter and chlorophyll a, as well as BOD 5 significantly lowered water quality, whereas heavy metal levels generally didn t exceed values characteristic for pure or slightly contaminated waters. Molluscs are an important component of bottom macrofauna both in the Bug River channel and in floodplain water bodies, where gastropods dominate [Jurkiewicz-Karnkowska 2004, 2006, 2008, 2009]. They are known as good bioindicators of heavy metal contamination [Jurkiewicz-Karnkowska 1998], however gastropods have been less frequently considered as bioindicators than bivalves [Królak 1998, Oertel 1998, Jurkiewicz-Karnkowska and Królak 1999, 2003, Flessas et al. 2000]. The present study aimed at a comparison of heavy metal concentrations (Cu, Zn, Mn, Fe, Cd and Pb) in the soft tissues and shells of selected gastropod species from the river channel and floodplain water bodies, as well as among different water bodies (intraspecific differences). Interspecific differences in heavy metal concentrations were also analyzed. 2. Materials and methods Heavy metal concentrations (Cu, Zn, Mn, Fe, Pb, Cd) were analysed in the soft tissues and shells of three gastropod species: Lymnaea stagnalis, Viviparus viviparus and Viviparus contectus. Molluscs were collected in summer 2007and 2009 in 18 floodplain water bodies within the lower Bug River valley, as well as in the river channel. The selected water bodies differed in distance from the river channel, hydrological connectivity with the river, size, successional stage. Molluscs of standardized size (L. stagnalis mm, V. viviparus mm, V. contectus mm) were used for analyses. Samples of individuals were dried after separation of the soft tissues from the shells and than homogenized. Subsamples of the soft tissues (0.5 g) and shells (1 g) were mineralized in concentrated nitric acid and 30 % perhydrol (Merck suprapur). Heavy metal concentrations were determined with AAS technique: Cu, Zn, Mn and Fe with flame method, Pb and Cd in graphite cuvette (Carl Zeiss Jena, AAS 30). Interspecific and intraspecific differences in heavy metal concentrations were analysed. The comparison of heavy metal concentrations was possible for all the three gastropod species among floodplain water bodies, whereas 317

3 Ewa Jurkiewicz-Karnkowska in the river channel only L. stagnalis and V. viviparus were found. To test for statistically significant intra- and interspecies differences in heavy metal concentrations in L. stagnalis and V. viviparus from floodplain water bodies four habitats were selected where these two species co-occurred. The results were statistically elaborated using STATISTICA 6.0 software. Non-parametric Kruskal-Wallis ANOVA was used to compare heavy metal concentrations in different species and in individual species from different habitats. 3. Results and discussion The analysis of heavy metal concentrations in the soft tissues and shells of L. stagnalis, V. viviparus and V. contectus showed considerable ranges of values for individual species (Fig. 1). This might result from both interspecific differences (i.e. between different species from the same habitat) and intraspecific variability (i.e. concerning one species from different habitats). Significantly higher Mn and Cd concentrations and lower Zn concentration in the soft tissues were found in L. stagnalis as compared to Viviparus spp. (Kruskal-Wallis ANOVA, p<0.05). Similar trend was observed in the case of shells. Differences in heavy metal concentrations in the soft tissues and shells between V. viviparus and V. contectus were not statistically significant. This might result from a similar mode of life and feeding of these closely related prosobranch species. No significant influence of hydrological connectivity of water body with the river channel on heavy metal levels in molluscs was observed. Generally concentrations of the analysed metals found in the studied molluscs were characteristic of uncontaminated or only slightly contaminated aquatic environments [e.g. Manly and George 1977, Willis 1983, Bias and Karbe 1985, Van Hattum et al. 1991, Smith et al. 1996]. Comparison of heavy metal levels in L. stagnalis and V. viviparus from floodplain water bodies and the river channel revealed that they were mostly similar in these two habitat types or higher in the former one (Fig. 2). Statistically significant differences were found in the concentrations of Fe in V. viviparus, Mn in both species and Cd in L. stagnalis. Higher concentrations of some metals in molluscs collected from floodplain water bodies as compared to the specimens from the river might result from more intense accumulation of heavy metals in lentic habitats (i.e. floodplain water bodies) than in the river channel. This tendency is relatively weak, because no sources of heavy metal contamination are present within the study area. The lower Bug River valley is an area of extensive farming forms and generally low degree of human impact and river water is generally not contaminated with heavy metals [Woyciechowska and Dojlido 2003]. Concentrations of the studied metals were lower in molluscs from the terminal section of the Bug River than mean values reported for the representatives of the same species collected in the Zegrzyński Reservoir [Jurkiewicz- Karnkowska 2004]. 318

4 Accumulation of heavy metals in selected gastropod species: lower Bug River and... Fig. 1. Heavy metal concentrations [μg/g dry wt] in the soft tissues (A) and shells (B) of three gastropod species from floodplain water bodies: Viviparus viviparus (V.v.), Lymnaea stagnalis (L.s.) and Viviparus contectus (V.c.) Rys. 1. Stężenia metali ciężkich [μg/g s.m.] w tkankach miękkich (A) i muszlach (B) trzech gatunków ślimaków ze zbiorników terenów zalewowych: Viviparus viviparus (V.v.), Lymnaea stagnalis (L.s.) i Viviparus contectus (V.c.) 319

5 Ewa Jurkiewicz-Karnkowska Fig. 2. Heavy metal concentrations [μg/g dry wt] in the soft tissues (A) and shells (B) of two gastropod species: Viviparus viviparus and Lymnaea stagnalis comparison of values in floodplain water bodies (FWB) and the river channel (R) Rys. 2. Stężenia metali ciężkich [μg/g s.m.] w tkankach miękkich (A) i muszlach (B) w dwóch gatunkach ślimaków: Viviparus viviparus i Lymnaea stagnalis porównanie wartości w zbiornikach terenów zalewowych (FWB) i w korycie rzeki (R) 320

6 Accumulation of heavy metals in selected gastropod species: lower Bug River and... Heavy metal concentrations in V. viviparus and L. stagnalis from four selected water bodies where these species co-occurred are presented in Table 1. Comparison of these values haven t reveal any significant interspecific differences. In the case of intraspecific variation within the same four water bodies (Table 2) many marginally significant differences were found (Kruskal-Wallis test, p ~ 0.1 or less), and the other p values were also relatively low. In the case of the soft tissues such differences were found for Fe, Mn, Pb and Cd, whereas in the shells for Cu, Zn and Mn. Table 1. Mean concentrations of heavy metals (±SD) in the soft tissues and shells of two gastropods Viviparus viviparus and Lymnaea stagnalis collected in four selected floodplain water bodies, where these species co-occurred Tabela 1. Średnie stężenia metali ciężkich (±SD) w tkankach miękkich i muszlach dwóch gatunków ślimaków Viviparus viviparus i Lymnaea stagnalis zebranych w czterech wybranych zbiornikach terenów zalewowych, w których te gatunki współwystępowały Species V. viviparus L. stagnalis V. viviparus L. stagnalis Heavy metal concentrations, μg/g dry wt Cu Zn Mn Fe Pb Cd Soft tissues 19.5± ± ± ± ± ± ± ± ± ±392.4 Shells 297.1± ± ± ± ± ± ± ± ± ± ± ± ± ±0.002 Table 2. Mean heavy metal accumulation in gastropods from four selected floodplain water bodies. Marginally significant differences (Kruskal-Wallis test, p ~ 0.1) in bold Tabela 2. Średnia kumulacja metali w ślimakach z czterech wybranych zbiorników terenów zalewowych. Znaczne różnice (test Kruskala-Wallisa, p ~ 0.1) zaznaczono pogrubioną czcionką Water body Heavy metal concentrations, μg/g dry wt Cu Zn Mn Fe Pb Cd Soft tissues 19.9± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±185.5 Shells 197.0± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±0.003 Relatively more pronounced differences in metal concentrations in one species from four water bodies as compared to two species from the same habitat may show that the 321

7 Ewa Jurkiewicz-Karnkowska studied molluscs reflect bioavailable concentrations of metals, but they are less sensible bioindicators in slightly contaminated waters. 4. Conclusions 1. Concentrations of heavy metals analysed in gastropods were relatively low and characteristic for uncontaminated or slightly contaminated environments. 2. Heavy metal level was in some cases higher in molluscs from floodplain water bodies as compared to the same species from the river channel. This difference may indicate more intense accumulation of at least some metals in floodplain habitats. 3. Intraspecific differences in heavy metal concentrations in analysed gastropods were better pronounced than interspecific ones indicating that the studied molluscs may reflect bioavailable heavy metal concentrations in the environment, however their sensibility is relatively low in uncontaminated habitats. Acknowledgements: This study was realized within the confines of the research project No N /3934 financed by the Ministry of Science and Higher Education. References Bias R., Karbe L Bioaccumulation and partitioning of cadmium within the freshwater mussel Dreissena polymorpha Pallas. Int. Rev. Ges. Hydrobiol. 70: Dojlido J., Kowalczewski W., Miłaszewski R., Ostrowski J. (eds) Rzeka Bug, zasoby wodne i przyrodnicze. IMGW, Warszawa. Flessass C., couillard y., pinel-alloul b., st-cyr l., campbell p. g. c Metal concentrations n two freshwater gastropods (Mollusca) in the St. Lawrence River and relationships with environmental contamination. Can. J. Fish. Aquat. Sci. 57 (Suppl. 1): Jurkiewicz-Karnkowska E Reakcje mięczaków na zanieczyszczenie środowisk wodnych metalami ciężkimi i możliwości ich wykorzystania w bioindykacji. Wiadomości Ekologiczne 44(3): Jurkiewicz-Karnkowska E Application possibilities of snails from the genus Lymnaea as bioindicators of heavy metals. Ekologija 2: Jurkiewicz-Karnkowska E Malacocoenoses of large lowland dam reservoirs of the Vistula River basin and selected aspects of their function. Folia Malacologica 12: Jurkiewicz-Karnkowska E Communities of aquatic molluscs in floodplain water bodies of lowland river (Bug River, East Poland). Polish Journal of Ecology 54: Jurkiewicz-Karnkowska E Aquatic mollusc communities in riparian sites of different size, hydrological connectivity and succession stage. Pol. J. Ecol. 56:

8 Accumulation of heavy metals in selected gastropod species: lower Bug River and... Jurkiewicz-Karnkowska E Diversity of aquatic malacofauna within a floodplain of a large lowland river (lower Bug River eastern Poland). J. Moll. Studies 75: Jurkiewicz-Karnkowska E., Królak E Poziom koncentracji miedzi (Cu), cynku (Zn), manganu (Mn), żelaza (Fe), ołowiu (Pb) i kadmu (Cd) w wybranych elementach środowiska (osady denne, wyższa roślinność wodna, ślimaki) dwóch zbiorników zaporowych. Ochrona Środowiska i Zasobów Naturalnych 18: Królak E Concentration of heavy metals in the snails Lymnaea (Radix) peregra (O. F. Müll.) and Lymnaea stagnalis (L.) occurring in rivers near Siedlce town. Pol. Arch. Hydrobiol. 45: Manly R., George W. O The occurrence of some heavy metals in populations of the freshwater mussel Anodonta anatina (L.) from the River Thames. Environ. Pollut. 14: Oertel N Molluscs as bioindicators of heavy metals in a side-arm system of the River Danube disturbed by engineering activity. Verh. Internat. Verein. Limnol. 26: Smith S., Chen M. H., Bailey R. G., Williams W. P Concentration and distribution of copper and cadmium in water, sediments, detritus, plants and animals in a hardwater lowland river. Hydrobiologia 341: Stan środowiska w województwie mazowieckim w 2009 roku Wojewódzki Inspektorat Ochrony Środowiska w Warszawie, Warszawa. Van Hattum B., Timmermans K. R., Govers H. A Abiotic and biotic factors influencing in situ trace metal levels in macroinvertebrates in freshwater ecosystems. Environ. Toxicol. Chem. 10: Willis M A comparative survey of Ancylus fluviatilis (Müller) population in the Afon Craftnant, N. Wales, above and below an input of zinc from mine-waste. Arch. Hydrobiol. 98: Woyciechowska J., Dojlido J Klasyfikacja jakości wód rzek. W: Dojlido J., Kowalczewski W., Miłaszewski R., Ostrowski J. (red) Rzeka Bug, zasoby wodne i przyrodnicze. IMGW, Warszawa: