Eggshell thinning of osprey (Pandion haliaetus) breeding in Sweden and its significance for egg breakage and breeding outcome.

In the middle of the 1960s low reproductive rate was found in several osprey (Pandion haliaetus) nests in Sweden. Therefore a project was started to investigate the production and to collect unhatched eggs and shell fragments in different regions of Sweden during 1971-2008. Measurements of osprey eggs from museum collections from 1840 to 1970 were included to study long-term changes in shell thickness. In total, eggshell thickness of whole eggs from 666 clutches and of shell fragments from 693 nests was measured. The thinnest shell fragments were recorded in 1973 (mean for 71 clutches: 0.438 mm), minus 15.0% compared to thickness of unaffected eggs before 1946 (0.515 mm). After 1973, shell thickness increased to reach background levels in 2003 (0.515 mm). Thus, it took 30 years to reach full thickness again. From the start of the decrease it took more than 50 years to reach unaffected conditions. The number of whole eggs remaining intact in the nest throughout incubation was reduced when shell thickness decreased. Great loss of eggs due to breakage seems to occur when the mean shell thickness in the clutch was below 0.40 mm. In 1971-1973, when shell thinning was most pronounced, the average thickness of shell fragments was 0.366 mm in nests with 0 intact eggs (minus 29% compared to the pre-1946 background value); 0.393 mm (minus 24%) in nests with 1 intact egg; 0.431 mm (minus 16%) in nests with 2 intact eggs and 0.450 mm (minus 12%) in nests with 3 intact eggs. Differences in thickness were significant for 1 versus 2 intact eggs, 2 vs. 3 intact eggs and for 0+1 vs. 2+3 intact eggs. Actual data from the period 1971-73 shows a decline in the production of young (4-5 weeks) of some 15% (0.25 young per nest).

Temporal trends of polybrominated diphenyl ethers and hexabromocyclododecane in milk from Stockholm mothers, 1980-2004.

Environmental and human exposures to brominated flame retardants (BFR) have been of emerging concern since some BFR are persistent and bioaccumulative compounds. Among those, polybrominated diphenyl ethers (PBDE) have frequently been reported in low to high ng/g concentrations in human blood around the world while hexabromocyclododecane (HBCDD) only occasionally has been reported and then in the low ppb concentrations in human blood. The present study concerns PBDE congener and HBCDD concentrations in human milk from Stockholm from 1980 to 2004. HBCDD concentrations has increased four to five times since 1980 until 2002 but seems to have stabilized at this concentration in the last years (2003/04). Similarly, BDE-153 has continued to increase at least to 2001, after which it has stabilized in the mother's milk. Other PBDE congeners with four to five bromine substituents peaked 5 years earlier (1995) and are all decreasing. DecaBDE (BDE-209) is not a suitable biomarker for time trend studies according to the present results, showing no changes over time. This is likely due to its short apparent half-life in humans and poor transfer from blood to milk.

Decreasing lead levels in Swedish biota revealed by 36 years (1969-2004) of environmental monitoring.

Since the 1980s, lead levels decreased significantly in most marine biota from the Baltic Sea, the Kattegatt and the Skagerrack and in terrestrial biota from south and central Sweden, analysed in the National Swedish Environmental Monitoring Programme. In herring and cod liver, the decrease was 4.2-7.1% annually 1981-2003 and in perch liver and guillemot eggs analysed since the middle of the 1990s the decrease was 10-13%. In kidneys of young starlings from south and central Sweden, lead levels decreased 6.2-12% annually and the annual decrease in liver and kidney from young moose was 8.8% and 6.5%, respectively. In northern Sweden, lead levels decreased in pike liver by 2.8% between 1969 and 1994 and in reindeer liver by 3.5% annually while a significant increase (5% annually 1981-1994) has been detected in arctic char. In some marine biota, there were indications of a larger decrease during the last ten years compared to the whole period. The large decline in lead emission to the atmosphere during the last twenty years, mainly because of decreasing use of leaded gasoline has obviously resulted in decreasing lead levels in biota.

A statistical resampling method to calculate biomagnification factors exemplified with organochlorine data from herring (Clupea harengus) muscle and guillemot (Uria aalge) egg from the Baltic sea.

A novel method for calculating biomagnification factors is presented and demonstrated using contaminant concentration data from the Swedish national monitoring program regarding organochlorine contaminants (OCs) in herring (Clupea harengus) muscle and guillemot (Uria aalge) egg, sampled from 1996 to 1999 from the Baltic Sea. With this randomly sampled ratios (RSR) method, biomagnification factors (BMF(RSR)) were generated and denoted with standard deviation (SD) as a measure of the variation. The BMFRsR were calculated by randomly selecting one guillemot egg out of a total of 29 and one herring out of a total of 74, and the ratio was determined between the concentration of a given OC in that egg and the concentration of the same OC in that herring. With the resampling technique, this was performed 50 000 times for any given OC, and from this new distribution of ratios, BMF(RSR) for each OC were calculated and given as geometric mean (GM) with GM standard deviation (GMSD) range, arithmetic mean (AM) with AMSD range, and minimum (BMF(MIN)) as well as maximum (BMF(MAX)) biomagnification factors. The 14 analyzed OCs were p,p'DDT and its metabolites p,p'DDE and p,p'DDD, polychlorinated biphenyls (PCB congeners: CB28, CB52, CB101, CB118, CB138, CB153, and CB180), hexachlorocyclohexane isomers (alpha-, beta-, and gammaHCH), and hexachlorobenzene (HCB). Multivariate data analysis (MVDA) methods, including principal components analysis (PCA), partial least squares regression (PLS), and PLS discriminant analyses (PLS-DA), were first used to extract information from the complex biological and chemical data generated from each individual animal. MVDA were used to model similarities/dissimilarities regarding species (PCA, PLS-DA), sample years (PLS), and sample location (PLS-DA) to give a deeper understanding of the data that the BMF modeling was based upon. Contaminants that biomagnify, that had BMF(RSR) significantly higher than one, were p,p'DDE, CB118, HCB, CB138, CB180, CB153, ,betaHCH, and CB28. The contaminants that did not biomagnifywere p,p'DDT, p,p'DDD, alphaHCH, CB101, and CB52. Eventual biomagnification for gammaHCH could not be determined. The BMF(RSR) for OCs present in herring muscle and guillemot egg showed a broad span with large variations for each contaminant. To be able to make reliable calculations of BMFs for different contaminants, we emphasize the importance of using data based upon large numbers of, as well as well-defined, individuals.

The tail feathers of osprey nestlings (Pandion haliaetus L.) as indicators of change in mercury load in the environment of southern Sweden (1969-1998): a case study with a note on the simultaneous intake of selenium.

The tail feathers of 104 osprey nestlings (Pandion haliaetus) from Lake Asnen, southern Sweden, were analyzed for total mercury and selenium content. Concentrations of mercury in feathers from the western part of the lake fell during the period 1969-1998, when pollution from industrial mercury had decreased and a paper mill upstream of the lake was closed down in 1979. Nestlings from the eastern part of the lake had initially lower levels of mercury, predominantly from atmospheric fallout. The levels did not decrease during the period. The reason for the differences seems to be the limited water flow between the western and the eastern part of the lake. The selenium concentrations were constant over time and approximately the same in both parts of the lake. The total-Hg/Se ratio in the western part of the lake was 2.94, which is somewhat higher than the 1:1 molar ratio constant (2.54). This indicates that the bioaccumulated quantity of selenium which is thought to be protective for the organisms against the toxic effects of mercury, is somewhat insufficient to bind all body mercury.