HEAVY METALS IN THE MARINE ENVIRONMENT Mercury Levels in Great Cormorant's Feathers from the Vistula Lagoon Ecosystem in Poland M. Misztal - Szkudlińska 1, P. Konieczka 2, J. Namieśnik 3, P. Szefer 4 1Department of Food Sciences, Medical University of Gdańsk, Gen. J. Hallera 107, PL 80-416 Gdańsk, POLAND, [email protected] 2Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology, G. Narutowicza 11/12, PL 80-233 Gdańsk, POLAND, [email protected] 3Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology, G. Narutowicza 11/12, PL 80-233 Gdańsk, POLAND, [email protected] 4Department of Food Sciences, Medical University of Gdańsk, Gen. J. Hallera 107, PL 80-416 Gdańsk, POLAND, [email protected] Abstract Monitoring of Hg in the marine environment is a priority. Some tissues of aquatic birds, as top predators, may exhibit high mercury levels due to food chain biomagnification. Birds are able to eliminate a substantial portion of their body burden of certain heavy metals via their plumage during the moulting period. During the moult, levels of some heavy met- als in internal tissues drop as they are sequestered in the feathers. The contour and tail feathers were collected from adult birds of Great Cormorant (n=44) from the Vistula Lagoon ecosystem in Poland. Feathers samples were rinsed three times with distilled water, deter- gent, Milli-Q water and with acetone. After drying at room temperature for one night, the total Hg concentration was determined by cold-vapor AAS technique (MA - 2000 Mercury Analyzer). In order to estimate trueness of the analytical measurements, the certified refer- ence materials such as DORM-2 and BCR-463 were used. The total Hg concentrations in contour feathers (9.73±5.63 µg/g d.w) were higher than in tail feathers (6.43±4.21 µg/g d.w) (p<0.005, U-test). Since feathers have been used as possible monitoring tissues for the exposure of birds to Hg, further studies are needed to support this finding. Key words: Mercury, Great Cormorant, feathers, biomonitoring, CV-AAS Introduction Material and Methods In aquatic environments Hg is convert- The birds were collected by shotgun at ed to methylmercury, and in this form is rap- the Vistula Lagoon (by permission of the idly incorporated into the food chain. Aquat- local environment protection authorities). ic birds, which are the top predators of food Contour and tail feathers were chosen for chain, may be exposed to significant concen- analyses. Samples were rinsed three times trations of Hg. They might serve as good by water with detergent, distilled water with monitors of spatial and temporal patterns of acetone (1:1) and next Mili-Q water (Saeki et Hg contamination in water ecosystems al. 2000). Then feathers were dried at room (Ochoa-acuna et al. 2002, Monteneiro and temperature by the one night to a constant Furness 1995). Feathers serve as a useful weight (Burger and Gochfeld 1997). Samples indicator of inorganic pollutants because were homogenized and the total Hg concen- metal concentration correlate well with their tration was determined by cold-vapor AAS internal levels during the time of feathers technique (MA - 2000 Mercury Analyzer). formation. Mercury level is also stable in Samples were thermally decomposed at feathers (Burger and Gochfeld 1997) and can 800°C under clean air flow and Hg was be bound to the sulphydryl groups of the ker- determined by CV-AAS at 253.65 nm. atin as feathers grow. Birds can excrete con- Three analytical subsamples were prepared tamination during the moult period as the from each sample. Each sample was consist- most important pathway elimination of Hg ed of 5-10 contour or tail feathers taken from (Dauve et al. 2003, Ochoa-acuna et al. one specimen. Quality control was assured 2002). by analyses of CRMs, i.e. DORM-2 (Nation- The aim of this study was to analyze al Research Council, Canada) and BCR-463 the total Hg level in feathers of Great Cor- (IRMM, Belgium). The respective recoveries morants from the Vistula Lagoon and its of the total Hg were 101.0 and 97.1%; the comparison to that in the other aquatic birds' respective standard deviations amounted to feathers. 15 th ICHMET 615 HEAVY METALS IN THE MARINE ENVIRONMENT 0.09 and 0.09%. Other validation parame- µg/g d.w.). Inverse tendency was observed in ters for the analytical method were described the case of tail feathers; smaller Hg concen- by Misztal-Szkudlińska et al. (2008). The tration was observed in females (5.57±4.20 concentration data were processed statisti- µg/g d.w.) than in males (7.01±4.22 µg/g cally by STATISTICA 8.0 for Windows d.w.) Variations of Hg concentrations in the (Copyright© StatSoft, Inc. 1984-2008). The two kinds of feathers are shown in Figure 2. nonparametric Mann-Withney U test Feathers of cormorant from the Vistula (p<0.005) was used for checking statistical- Lagoon ecosystems are characterized by sig- ly significant dependence of Hg concentra- nificantly higher level of Hg as compared to tions on different kinds of feathers. cormorants from Japan. According to Saeki et al. (2000) and Nam et al. (2005) Great Results and Discussion Cormorant's feathers contained ca. 3 µg Hg/g Concentration of Hg in contour feath- d.w. Phalacrocorax auritius from two reser- ers (9.73±5.63 µg/g d.w.) was significantly voirs in New Mexico concentrated Hg at lev- higher than that in tail feathers (6.43±4.21 els of 4.01 and 2.34 µg/g w.w. in tail feathers µg/g d.w.) (Mann-Withney U test; p<0.005) (Caldwell et al. 1999). (Figure 1). Female contour feathers con- tained 10.6±6.69 µg Hg/g d.w. while male ones had somewhat lower levels (8.98±4.55 Figure 1. Concentrations of total Hg (µg/g d.w.) in Great Cormorants feathers. Figure 2. Concentrations of total Hg (µg/g d.w.) in feathers from male and female Great Cormorants. 616 15 th ICHMET HEAVY METALS IN THE MARINE ENVIRONMENT Very low level of Hg (0.251 µg/g d.w.) Africa. Environ Monit Assess 2001;69:196- has been observed by Burger and Gochfeld 203. (2001) in the feathers of Cape Cormorant Burger J, Gochfeld M. Risk, mercury (Phalacrocorax capensis) from Namibia in levels and birds: relating adverse laboratory southern Africa. Great cormorants analysed effects to field biomonitoring. Environ Res in our studies contained in feathers similar 1997;75:160-172. concentration of Hg to that in royal albatross Caldwell CA, Arnold MA, Gould WR. (6.8 µg/g d.w.) and black-footed albatross (7.2 Mercury distribution in blood, tissues, and µg/g d.w.) from Japan as well as in herring gull feathers of Double-Creased Cormorant (6.06 µg/g d.w.) and glaucous gull (5.96 µg/g nestlings from Arid-lands reservoirs in south d.w.) from Siberia (Kim et al. 1996 a, b). central New Mexico. Arch Environ Contam Ochoa-acuna et al. (2002) found differ- Toxicol 1999,36:456-461. ences in Hg concentrations in contour feath- Dauwe T, Bervoets L, Pinxten R, Blust ers across taxonomic bird groups. They R, Eens M. Variation of heavy metals within assumed that correlation depends on feeding and among feathers of birds of prey: effects of strategy and to a less extent on differences in molt and external contamination. Environ the metabolism and excretion of Hg. The Pollut 2003,124:429-436. highest levels of Hg were observed in Procel- Kim EY, Ichihashi H, Saeki K, lariide, Sulidae, Laridae and Phalacrocoraci- Atrashkevich G, Tanabe S, Tatsukawa R. dae whilst Charadriidae, Threskiornithidae Metal accumulation in tissues of seabirds and Anatidae contained the lowest its levels. from Chaun, northeast Siberia, Russia. Env- Birds from genus Phalacrocorax are iron Pollut 1996b,92:247-252. mainly fish-eating, so they have been able to Kim EY, Murakami T, Seaki K, Tat- accumulate contamination like Hg. sukawa R. Mercury levels and its chemical Limited data for Hg levels in feathers form in tissues and organs of seabirds. Arch indicate a range of 5 to 40 µg/g d.w. as being Environ Contam Toxicol 1996a,30:259- associated with adverse effects connected 266. with lower reproduction and survival (Burger Misztal-Szkudlińska M, Konieczka P, and Gochfeld 1997, 2000). Feathers of Great Namieśnik J, Szefer P. Total mercury in Cormorants from Vistula Lagoon are charac- Great Cormorant (Phalacrocorax carbo) and terized by generally higher levels of Hg as fish in Polish sector of Vistula Lagoon. 14th compared to those from other regions world- International Conference on Heavy Metals wide. Since feathers have been used as possi- in the Environment, Taipei, Taiwan, 23 - ble monitoring tissues for the exposure of 30.11.2008 birds to Hg, further studies are needed to Monteiro LR, Furness RW. Seabirds as support this finding. monitors of mercury in the marine environ- ment. Water Air Soil Pollut 1995;80:851- Acknowledgements 870. The authors gratefully acknowledge Nam DH, Anan Y, Ikemoto T, Okabe the financial support received from grant no. Y, Kim E-Y, Subramanian A. Specific accu- N305 049336 of the Polish Ministry of mulation of 20 trace elements in Great Cor- Science and Higher Education. We are morants (Phalacrocorax carbo) from Japan. indebted to Dr. Gerard Kanarek who assisted Environ Pollut 2005,134:503-514. with collecting the biological material. Ochoa-acuna H, Sepúlveda MS, Gross TS. Mercury in feathers from Chilean birds: References influence of location, feeding strategy, and Burger J, Gochfeld M. Metal levels in taxonomic affiliation.