Polychlorierte Naphthaline

Measurements show that PCN may occur in industrial waste and residues in the mg/kg range. Investigations were carried out with optimized parameters for GC and MS using two different GC/MS-systems. Chromatograms were obtained for a variety of chlorination degrees using capillary columns of different polarities. It is proposed to quantify PCN using relevant single compounds comparable to the analysis of polychlorinated biphenyls.     

PCDD/PCDF-Kontaminationen aus Kieselrot von Sport- und Spielanlagen

Surfaces of many sports fields, playgrounds and paths in Germany are covered with red slag ?Kieselrot”. Kieselrot is extremely high contaminated by polychlorinated dibenzodioxines and dibenzofurans. Mean PCDD/F-concentration in surface layers of 35 locations in Hessen is 45 500 ng I-TE/kg. PCDD/F-contents range from 1 000 to 250 ng I-TE/kg within 10 cm under surface layers and from 6 000 to 600 ng I-TE/kg in top soils of three metres wide peripheral areas. Concentration in subsoils is a function of depth (n=18, r=?0,741), concentration in topsoils of peripheral areas is a function of distance from large sports fields (n=14, r=?0,881) or small sportsfields (n=23, r=?0,742), respectively. A 15 metres wide and 10 centimetres deep peripheral area contains 0,8 g I-TE PCDD/F. The pollution of surroundings and further observations indicate that ?Kieselrot-areas” must be regarded as important dioxin sources.     

Age-structured modeling reveals long-term declines in the natality of western Steller sea lions.

Since the mid-1970s, the western Steller sea lion (Eumetopias jubatus), inhabiting Alaskan waters from Prince William Sound west through the Aleutian Islands, has declined by over 80%. Changing oceanographic conditions, competition from fishing operations, direct human-related mortality, and predators have been suggested as factors driving the decline, but the indirect and interactive nature of their effects on sea lions have made it difficult to attribute changes in abundance to specific factors. In part, this is because only changes in abundance, not changes in vital rates, are known. To determine how vital rates of the western Steller sea lion have changed during its 28-year decline, we first estimated the changes in Steller sea lion age structure using measurements of animals in aerial photographs taken during population surveys since 1985 in the central Gulf of Alaska (CGOA). We then fit an age-structured model with temporally varying vital rates to the age-structure data and to total population and pup counts. The model fits indicate that birth rate in the CGOA steadily declined from 1976 to 2004. Over the same period, survivorship first dropped severely in the early 1980s, when the population collapsed, and then survivorship steadily recovered. The best-fitting model indicates that in 2004, the birth rate in the central Gulf of Alaska was 36% lower than in the 1970s, while adult and juvenile survivorship were close to or slightly above 1970s levels. These predictions and other model predictions concerning population structure match independent field data from mark-recapture studies and photometric analyses. The dominant eigenvalue for the estimated 2004 Leslie matrix is 1.0014, indicating a stable population. The stability, however, depends on very high adult survival, and the shift in vital rates results in a population that is more sensitive to changes in adult survivorship. Although our modeling analysis focused exclusively on the central Gulf of Alaska, the western Gulf of Alaska and eastern Aleutians show a similar pattern of declining pup fraction with no increase in the juvenile, or pre-breeding, fraction. This suggests that declining birth rate may be a problem for western Steller sea lions across the Gulf of Alaska and into the Aleutian Islands.     

Setting of the American oyster Crassostrea virginica in the James River,Virginia, USA: temporal and spatial distribution

Setting of larvae of the oyster Crassostrea virginica was monitored in the James River, Virginia, USA from 1963 to 1980. Setting patterns were similar in two ways to those described prior to 1960 (before the onset of the oyster pathogen Haplosporidium nelsoni (MSX) in Chesapeake Bay): (1) setting intensity (average number of spat per shell) was greater at stations in the lower than upper estuary, and (2) on the average, 60 to 80% of the total annual set at each station occurred during a 6-week period from mid-August through September. However, annual setting intensity from 1963–1980 was lower than previously recorded, and annual sets occurred as a series of discrete pulses rather than continuously throughout the season. Pulses were each approximately 1 to 2 weeks in duration and separated by a period of diminished or no setting. Cross-correlation analysis of annual setting patterns among stations revealed three zones in the James River: the upper estuary and entire southwest side, the lower estuary, and a mid-estuary transition zone. Setting pulses tended to be synchronous at stations within each zone, but occurred 1 to 2 weeks later at stations in downriver than in upriver zones. The location of zones is related to known aspects of water circulation in the James River estuary. Moreover, pulse setting itself may be related to the absence of strong vertical salinity gradients accompanying the fortnightly stratification-destratification process.Contribution No. 1213 from the Virginia Institute of Marine Science, School of Marine Science, The College of William and Mary